Note: Descriptions are shown in the official language in which they were submitted.
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VENTILATOR SYSTEM
Cross-references to related applications
[0001] This application is a continuation-in-part application of U.S. patent
application
13/931,465, entitled "LOW-NOISE BLOWER," filed June 28, 2013, attorney docket
number
080625-0422, U.S. patent application 13/931,486, entitled "FLOW SENSOR," filed
June 28,
2013, attorney docket number 080625-0423, U.S. patent application 13/931,566,
entitled
"MODULAR FLOW CASSETTE," filed June 28, 2013, attorney docket number 080625-
0424,
U.S. patent application 13/931,418, entitled "VENTILATOR EXHALATION FLOW
VALVE,"
filed June 28, 2013, attorney docket number 080625-0425, and U.S. patent
application
13/931,496, entitled "FLUID INLET ADAPTER," filed June 28, 2013, attorney
docket number
080625-0427. The entire content of these applications are incorporated herein
by reference.
[0002] This application is related to co-pending application U.S. patent
application 14/318,285,
entitled "FLUID INLET ADAPTER," attorney docket number 080625-0657, and U.S.
patent
application 14/318,274, entitled "VENTILATOR FLOW VALVE," attorney docket
number
080625-0658. The entire content of these applications are incorporated herein
by reference.
BACKGROUND
Field
[0003] The present disclosure generally relates to ventilation systems and, in
particular, to a
modular ventilation system.
Description of the Related Art
[0004] Patients with respiratory injury, such as chronic respiratory failure,
may be provided with
a ventilator or respirator to assist with their breathing or, in severe cases,
take over the breathing
function entirely. Ventilators typically provide a flow of air, or other
breathing gases, at an
elevated pressure during an inhalation interval, followed by an exhalation
interval where the
pressurized air is diverted so that the air within the patient's lungs can be
naturally expelled. The
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inhalation interval may be initiated upon detection of a patient's natural
inhalation or by the
ventilator.
[0005] Ventilators are available in a variety of sizes with different ranges
of air flows and
pressures that can be provided. For example, a neonatal patient will require a
much lower
pressure and volume of air per breath than an adult.
[0006] In some respirators that use a blower to pressurize the gas provided to
the patient, the
blowers that are used are loud and the noise level in the patient's room is
commonly 65 dB or
more. This level of noise may disrupt the patient's rest and sleep as well as
cause fatigue for the
caregiver and may further obstruct diagnosis and monitoring of the patient by
masking the
natural breathing noises that provide an indication of the patient's
condition.
[0007] Some respirators may be configured to accept one or more breathing
gases, for example
"pure oxygen" or "heliox 80/20" (a mixture of 80% helium with 20% oxygen) from
external
sources. The exact gas mixture delivered to the patient, however, may be a
mixture of various
breathing gases since the specific percentage required for a particular
patient may not be
commercially available and must be custom mixed in the respirator. It is
important to provide
precisely the specified flow rate of gas to the patient, particularly for
neonatal patients whose
lungs are small and very susceptible to damage from overinflation.
SUMMARY
[0008] Described herein are ventilators and ventilator components. The
ventilator components
may be modular such that ventilators may comprise various combinations of
ventilator
components described herein. The modular ventilator components may be
removable or
otherwise interchangeable.
[0009] In certain embodiments, a ventilator is disclosed comprising a blower
and a flow control
device, wherein the blower is in fluid communication with the flow control
device. The blower
comprises a housing defining an impeller cavity, an impeller plate disposed
within the impeller
cavity and comprising an outside edge and one or more vanes disposed on the
impeller plate and
comprising a leading surface and a trailing surface connecting at a tip,
wherein the leading
surface comprises a first portion abutting a second portion, the first portion
extends from the tip
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with a first radius, the second portion extends from the tip with a second
radius, the first radius is
smaller than the second radius. The flow control device comprises a fixed
magnetic field, a drive
coil configured to move within the fixed magnetic field in response to a low
frequency signal and
configured to receive a high frequency signal, a detection coil adjacent the
drive coil and
configured to detect the high frequency signal in the drive coil, the detected
high frequency
signal corresponding to a position of the drive coil, a processor coupled to
the high frequency
source and the low frequency source and configured to receive the detected
high frequency
signal form the detection coil, a seal configured to move based on the
position of the drive coil,
and a valve orifice defining a valve seat and a variable opening, the variable
opening being
adjustable based on a position of the seal relative to the valve seat.
[0010] In certain embodiments, a ventilator is disclosed comprising a flow
cassette and a fluid
inlet adapter. The flow cassette comprises a fluid passage terminating at an
inlet and an outlet, a
temperature sensor disposed within the fluid passage and configured to detect
a temperature, a
flow rate sensor disposed within the fluid passage and configured to detect a
flow rate, and a
processor configured to determine a compensated flow rate based on the
temperature and the
flow rate. The fluid inlet adapter comprises a first inlet end configured to
connect to a fluid
source, a second inlet end configured to removably connect to the inlet of the
flow cassette, a
latching component configured to secure the fluid inlet adapter to the flow
cassette, and a
machine-readable indicator for identifying the fluid source.
[0011] In certain embodiments, a ventilator is disclosed comprising a flow
sensor comprising a
fluid passage, a flow restriction disposed within the fluid passage such that
a fluid passing
through the fluid passage must pass through the flow restriction, a first
pressure sensor coupled
to a first end of the fluid passage and configured to detect a first pressure,
a second pressure
sensor coupled to a second end of the fluid passage and configured to detect a
second pressure,
such that the flow restriction is between the first and second pressure
sensors, a temperature
sensor coupled to the fluid passage and configured to detect a temperature,
and a flow sensor
processor configured to determine a compensated flow rate based at least on
the first pressure,
the second pressure, and the temperature.
[0012] In certain embodiments, a blower is disclosed that has an impeller
comprising an impeller
plate and a plurality of blades each attached to the impeller plate. Each
blade has a tip and a
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leading surface that comprises a first portion proximate to the tip. The first
portion has a first
radius that is within a range of 0.03-0.20 inch.
[0013] In certain embodiments, an impeller is disclosed that has an impeller
plate having an
outside edge with a first radius and a plurality of blades attached to the
impeller plate. Each of
the plurality of blades comprises a tip at the outside edge and a leading
surface with a first
portion extending from the tip and a second portion that extends from the
first portion with a
second radius that is within the range of 0.14-0.16 inch.
[0014] Described herein are ventilators having a valve that is a software-
controlled valve used to
adjust the flow of gas passing through a port of the ventilator. The valve is
controlled by a
software control signal and works in conjunction with a ventilator's gas
delivery subsystems to
maintain user set pressure control levels. In continuous positive airway
pressure ("CPAP")
therapy, the valve preferably helps maintain a set pressure.
[0015] Described herein are ventilators having an exhalation valve that is a
software-controlled
valve used to adjust the flow of gas passing through an expiratory port of the
ventilator to the
outside environment. The exhalation valve is controlled by a software control
signal and works
in conjunction with a ventilator's gas delivery subsystems to maintain user
set pressure control
levels. In CPAP therapy, the exhalation valve preferably maintains a set
pressure, and outlet
flow is controlled at a specified target bias flow rate. Additional (demand)
flow is provided to
maintain the pressure in the event of patient inspiratory flow exceeding the
bias flow.
[0016] Some implementations described herein relate to a flow control device
comprising a high
frequency source configured to generate a high frequency signal, a low
frequency source
configured to generate a low frequency signal, and a fixed magnetic field. The
flow control
device further comprises a drive coil configured to move within the fixed
magnetic field in
response to the low frequency signal and configured to receive the high
frequency signal, and a
detection coil adjacent the drive coil and configured to detect the high
frequency signal in the
drive coil. The detected high frequency signal corresponds to a position of
the drive coil. The
flow control device further comprises a processor coupled to the high
frequency source and the
low frequency source and configured to receive the detected high frequency
signal from the
detection coil. The flow control device further comprises a seal configured to
move based on the
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position of the drive coil, and a valve orifice defining a valve seat and a
variable opening. The
variable opening is adjustable based on a position of the seal relative to the
valve seat.
[0017] Described herein are ventilator systems that include, for example, a
first valve connected
to a supply channel. The first valve comprises a first high frequency source
configured to
generate a first high frequency signal, a first low frequency source
configured to generate a first
low frequency signal, and a first fixed magnetic field. The first valve
further comprises a first
drive coil configured to move within the first fixed magnetic field in
response to the first low
frequency signal and configured to receive the first high frequency signal,
and a first detection
coil adjacent the first drive coil and configured to detect the first high
frequency signal in the
drive coil. The detected first high frequency signal corresponds to a position
of the first drive
coil. The first valve further comprises a first processor coupled to the first
high frequency source
and the first low frequency source and configured to receive the detected
first high frequency
signal from the first detection coil. The first valve further comprises a
first seal configured to
move based on the position of the first drive coil, and a variable first valve
orifice defining a first
valve seat. The first valve orifice is adjustable based on a position of the
first seal relative to the
first valve seat.
[0018] Described herein are also methods for adjusting pressure in a
ventilator line. Some
methods include sending a high frequency signal and a low frequency signal to
a drive coil. The
low frequency signal causes the drive coil to move within a fixed magnetic
field, and the drive
coil causes a seal to adjust a variable valve orifice of the valve. The
methods also include
detecting the high frequency signal in the drive coil, determining a velocity
of the drive coil
based on the detected high frequency signal, and modifying the low frequency
signal based on
the determined velocity of the drive coil.
[0019] Some embodiments described herein relate to a valve that includes a
valve orifice with an
adjustable opening; a fixed magnetic field; a force coil configured to be
moved within the fixed
magnetic field in response to a low frequency current; a current amplifier
configured to direct a
summed low frequency current and a high frequency current into the force coil;
a feedback coil
configured to detect the high frequency current in the force coil, the
detected high frequency
current having a magnitude that is proportional to a force coil position
within the fixed magnetic
field. The valve can also include a processor configured (i) to receive data
relating to the
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position of the force coil and (ii) to send instructions to the current
amplifier; and a diaphragm
configured to adjust the valve orifice opening based on the position of the
force coil.
[0020] Described herein are ventilator systems that include, for example, a
gas source configured
to provide a gas to a patient via a supply channel; an exhaust channel
configured to direct
exhaust gas from the patient; and an exhaust valve. The exhaust valve may
include a force coil
configured to be moved within a fixed magnetic field in response to a low
frequency current; a
current amplifier configured to direct a summed low frequency current and a
high frequency
current into the force coil; a feedback coil configured to detect the high
frequency current in the
force coil; a processor configured (i) to receive data relating to the
position of the force coil, (ii)
to receive data relating to pressure within the exhaust channel, and (iii) to
send instructions to the
current amplifier based on the position of the coil and the pressure; and a
diaphragm configured
to adjust opening of a valve orifice based on the instructions from the
processor.
[0021] Described herein are also methods for adjusting pressure in a
ventilator line. Some
methods include the following steps: directing a summed low frequency current
and a high
frequency current from a current amplifier into a force coil that is
configured (i) to be moved
within a fixed magnetic field in response to the low frequency current and
(ii) to control a
diaphragm to adjust opening of a valve orifice; detecting the high frequency
current in the force
coil, the detected high frequency current having a magnitude that is
proportional to a position of
the force coil within the fixed magnetic field; detecting the pressure in the
ventilator line; and
changing the low frequency current to move the force coil within the fixed
magnetic field,
thereby adjusting the opening of a valve orifice, in response to the detected
pressure.
[0022] The disclosed fluid inlet adapter provides a fluid inlet that can be
configured to accept
only one of two possible fluids at a time and provide a machine-readable
indication as to which
fluid is currently being accepted.
[0023] In certain embodiments, an adapter for providing fluid from a fluid
source to a device is
disclosed. The adapter comprises a housing and an inlet extending through the
housing for
connecting the fluid source to the device. The inlet comprises a first end for
connecting to the
fluid source and a second end for connecting to the device. The adapter
further comprises a
latching component configured to secure the adapter to the device, and a
machine-readable
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indicator for identifying the fluid source. The machine-readable indicator
extends away from the
first end of the inlet and beyond the second end of the inlet.
[0024] In certain embodiments, a flow sensor is disclosed that comprises a
flow restriction
disposed within a passage such that a fluid passing through the passage must
pass through the
flow restriction, an upstream pressure sensor coupled to the passage at a
point upstream of the
flow restriction and configured to measure and provide an upstream pressure of
the fluid within
the passage, a downstream pressure sensor coupled to the passage at a point
downstream of the
flow restriction and configured to measure and provide a downstream pressure
of the fluid within
the passage, a temperature sensor coupled to the passage and configured to
measure and provide
a temperature of the fluid within the passage, and a flow sensor processor
coupled to the
upstream and downstream pressure sensors and the temperature sensor and
configured to accept
measurements therefrom and calculate a compensated flow rate based at least in
part on the
measured pressures and temperature.
[0025] It is advantageous to provide a modular flow cassette that provides
accurate flow
measurements of a variety of gases and gas mixtures over a range of
temperatures and flow rates.
[0026] In certain embodiments, a flow cassette is disclosed that has a housing
with an inlet and
an outlet and a passage therebetween. The flow cassette also has a temperature
sensor disposed
within the passage and configured to measure the temperature of a fluid
flowing through the
passage, a flow rate sensor disposed within the passage and configured to
measure a flow rate of
the fluid flowing through the passage, and a processor coupled to the
temperature sensor and
flow rate sensor. The processor is configured to accept measurements of
temperature and flow
rate from the temperature sensor and flow rate sensor, respectively, and
provide a compensated
flow rate.
[0027] For purposes of summarizing the disclosure, certain aspects,
advantages, and novel
features of the disclosure have been described. It is to be understood that
not necessarily all such
advantages may be achieved in accordance with any particular embodiment of the
disclosure.
Thus, the disclosure may be embodied or carried out in a manner that achieves
or optimizes one
advantage or group of advantages as taught herein without necessarily
achieving other
advantages taught or suggested.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings, which are included to provide further
understanding and
are incorporated in and constitute a part of this specification, illustrate
disclosed embodiments
and together with the description serve to explain the principles of the
disclosed embodiments.
In the drawings:
[0029] FIGS. 1-2 are top and bottom perspective views of an exemplary blower
according to
certain aspects of the present disclosure.
[0030] FIG. 3 is an exploded view of the blower of FIG. 1 according to certain
aspects of the
present disclosure.
[0031] FIG. 4 is a perspective view of an exemplary impeller according to
certain aspects of the
present disclosure.
[0032] FIG. 5 is a perspective view of an exemplary impeller according to
certain aspects of the
present disclosure.
[0033] FIG. 6 is a close-up plan view of a vane tip of the impeller according
to certain aspects of
the present disclosure.
[0034] FIG. 7 is a cross-section of a blower according to certain aspects of
the present
disclosure.
[0035] FIG. 8 is an enlarged view of a portion of FIG. 7 according to certain
aspects of the
present disclosure.
[0036] FIGS. 9A-9C are perspective views of the overmolded top housing
according to certain
aspects of the present disclosure.
[0037] FIG. 10 depicts a patient using an exemplary ventilation system
according to certain
aspects of the present disclosure.
[0038] FIGS. 11A and 11B are front and rear views of an exemplary ventilator
according to
certain aspects of the present disclosure.
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[0039] FIG. 12 is a schematic representation of a ventilator according to
certain aspects of the
present disclosure.
[0040] FIGS. 13A-13B are schematic depictions of feedback systems according to
certain
aspects of the present disclosure.
[0041] FIG. 14 illustrates an exemplary schematic arrangement of a control
system according to
certain aspects of the present disclosure.
[0042] FIG. 15A is a cross sectional view of a flow valve according to certain
aspects of the
present disclosure.
[0043] FIG. 15B is a cross sectional view of a flow valve according to certain
aspects of the
present disclosure.
[0044] FIG. 16 is a schematic representation of a ventilator according to
certain aspects of the
present disclosure.
[0045] FIG. 17 shows a flowchart of a process for controlling a flow valve
according to certain
aspects of the present disclosure.
[0046] FIG. 18 illustrates high frequency signals according to certain aspects
of the present
disclosure.
[0047] FIGS. 19-20 are front and back perspective views of exemplary fluid
inlet adapters
according to certain aspects of the present disclosure.
[0048] FIG. 21A is a cross-sectional side view of an exemplary fluid inlet
adapter and a device
according to certain aspects of the present disclosure.
[0049] FIG. 21B is a cross-sectional side view of the exemplary fluid inlet
adapter mated with
the docking location of the housing according to certain aspects of the
present disclosure.
[0050] FIGS. 22A-22B depict the position of the handle in exemplary unlatched
and latched
positions according to certain aspects of the present disclosure.
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[0051] FIGS. 23 and 24 depict an exemplary inlet adapter configured to accept
fluid from two
different sources according to certain aspects of the present disclosure.
[0052] FIGS. 25-28 depict example connector configurations according to
certain aspects of the
present disclosure.
[0053] FIG. 29 depicts an adapter with one inlet according to certain aspects
of the present
disclosure.
[0054] FIG. 30 depicts adapters with different machine-readable indicators and
a flow control
device according to certain aspects of the present disclosure.
[0055] FIG. 31 depicts an adapter coupled to a flow control device according
to certain aspects
of the present disclosure.
[0056] FIG. 32 depicts frontal views of an adapter and a connector according
to certain aspects
of the present disclosure.
[0057] FIG. 33 depicts front views of an adapter and a flow control device
according to certain
aspects of the present disclosure.
[0058] FIG. 34 is a block diagram of an exemplary flow sensor according to
certain aspects of
the present disclosure.
[0059] FIG. 35A depicts an exemplary flow cassette according to certain
aspects of the present
disclosure.
[0060] FIG. 35B is a cross-section of the flow cassette of FIG. 35A according
to certain aspects
of the present disclosure.
[0061] FIG. 35C is an enlarged view of a portion of FIG. 35B showing an
exemplary flow sensor
according to certain aspects of the present disclosure.
[0062] FIG. 36 is a flow chart of an exemplary flow measurement process
according to certain
aspects of the present disclosure.
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[0063] FIG. 37 is a block diagram of an exemplary flow cassette according to
certain aspects of
the present disclosure.
[0064] FIGS. 38A-38B depict an exemplary flow cassette according to certain
aspects of the
present disclosure.
[0065] FIG. 39A is a cross-section of the flow cassette of FIGS. 38A-38B
according to certain
aspects of the present disclosure.
[0066] FIG. 39B is an enlarged view of a portion of FIG. 39A according to
certain aspects of the
present disclosure.
[0067] FIG. 40 is a flow chart of an exemplary configuration process according
to certain
aspects of the present disclosure.
[0068] FIG. 41 is an illustration of a ventilator according to certain aspects
of the present
disclosure.
DETAILED DESCRIPTION
[0069] In the following detailed description, numerous specific details are
set forth to provide a
full understanding of the present disclosure. It will be apparent, however, to
one ordinarily
skilled in the art that embodiments of the present disclosure may be practiced
without some of
the specific details. In other instances, well-known structures and techniques
have not been
shown in detail so as not to obscure the disclosure. In the referenced
drawings, like numbered
elements are the same or essentially similar. Reference numbers may have
letter suffixes
appended to indicate separate instances of a common element while being
referred to generically
by the same number without a suffix letter.
[0070] While the discussion herein is directed to a ventilator for use in a
hospital, the disclosed
concepts and methods may be applied to environments, such as a home or long-
term care
facility, and other fields, such as deep-sea diving, that would benefit from
accurate flow
measurement of a variety of gas mixtures. Those of skill in the art will
recognize that these same
features and aspects may also be applied to the sensing and control of other
fluids besides
medical gases.
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[0071] Within this document, the term "gas" shall be interpreted to mean both
a single material
in gaseous form, for example oxygen, and a mixture of two or more gases, for
example air or
heliox (a mixture of oxygen and helium). A gas may include water or other
liquids in the form
of vapor or suspended droplets. A gas may also include solid particulates
suspended in the gas.
[0072] Within this document, the term "pure," when used with reference to a
gas, means that the
gas meets commonly accepted medical standards for purity and content.
[0073] Within this document, the term "temperature sensor" means a device
configured to
measure temperature and to provide a signal that is related to the measured
temperature. A
temperature sensor may include electronics to provide a drive current or
voltage and/or measure
a current or voltage. The electronics may further include conditioning and
conversion circuitry
and/or a processor to convert the measured value to a signal that may be in
analog or digital
form.
[0074] Within this document, the term "pressure sensor" means a device
configured to measure a
gas pressure and provide a signal that is related to the measured pressure. A
pressure sensor may
include electronics to provide a drive current or voltage and/or measure a
current or voltage. The
electronics may further include conditioning and conversion circuitry and/or a
processor to
convert the measured value to a signal that may be in analog or digital form.
The pressure may
be provided in absolute terms or "gauge" pressure, i.e., relative to ambient
atmospheric pressure.
[0075] While the discussion herein is directed to the provision of compressed
air as part of a
medical respirator, the disclosed concepts and methods may be applied to other
fields that would
also benefit from a quiet, portable source of compressed air. For example,
conventional leaf
blowers that are commonly used to blow leaves and small garden debris into
piles are quite loud
and a blower of this type may be advantageous in place of the current blowers.
[0076] Described herein are ventilators having one or more valves that are
software-controlled
valves. These valves may be used to adjust the flow of gas passing through a
port of the
ventilator and can be configured to be positioned on the exhalation side of a
ventilation system
(meaning in connection with system components that receive exhaled air from a
patient) or on an
inhalation side of a ventilation system (meaning in connection with system
components that
provide air to a patient). The valves can be controlled by a software control
signal and work in
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conjunction with a ventilator's gas delivery subsystems to maintain user set
pressure control
levels. In CPAP therapy, an exhalation valve preferably maintains a set
pressure, and outlet flow
is controlled at a specified target bias flow rate. Additional (demand) flow
may be provided
through an inhalation valve to control the pressure.
[0077] An exhalation subsystem of a ventilator comprises an exhalation valve,
an exhalation
flow sensor, and a heated filter and water trap. As explained herein, the
exhalation valve is a
software-controlled valve that is used to adjust the flow of gas passing
through the expiratory
port of the ventilator to the outside environment. The exhalation valve is
controlled by a software
control signal and works in conjunction with a ventilator's gas delivery
subsystems to maintain
user set pressure control levels.
[0078] As explained herein, the exhalation valve operates on the principle of
a force balance
across a control diaphragm, which may be a disposable valve membrane. In some
embodiments,
a linear magneto-mechanical actuator controls a force on the diaphragm, which
in turn controls
the circuit or ventilator line pressure. The force generated by the actuator
is based on a command
from the software closed-loop controller.
[0079] FIGS. 1-2 are top and bottom perspective views of an exemplary blower
100 according to
certain aspects of the present disclosure. In the configuration of FIG. 1, the
blower 100 draws in
ambient air, or other gases if connected to a source of gas, through inlet 119
of housing 112.
Impeller 160 may rotate at a variable speed up to 30,000 rotations per minute
(rpm), for example,
to centrifugally accelerate the air and provide a flow of pressurized air at
outlet 118. In this
embodiment, the housing 112 comprises two parts, 112T and 1I2B (see FIG. 3)
held together
with multiple clips 114. The section line A-A indicates the cross-sectional
view of FIG. 7.
[0080] FIG. 2 is a perspective view of the blower 100 of FIG. 1 with the
blower 100 rotated so
as to make the bottom housing portion 1I2B visible. A motor 120 is attached to
the housing 112
and the shaft of the motor (not visible in FIG. 2) passes through the housing
112 and connects to
the impeller 160.
[0081] FIG. 3 is an exploded view of the blower 100 of FIG. 1 according to
certain aspects of the
present disclosure. The top housing portion 112T has an impeller cavity 119.
The impeller 160
is at least partially disposed within the impeller cavity 119 when the blower
100 is assembled.
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The housing 112 comprises a collector 116 formed when the top and bottom
housing portions
112T, 112B are mated. In this example, the collector 116 is shaped as a volute
having a circular
cross-sectional profile along a radial plane of the housing 112, wherein the
area of the profile
monotonically increases as the distance around the volute from the outlet 118
decreases. In
certain embodiments, the volute may have a non-circular profile. In certain
embodiments, the
area of the profile may be constant over a portion of the volute.
[0082] The top and bottom housing portions 112T, 112B also respectively
include edges 124U,
124L that are proximate to each other when the blower 100 is assembled and
surround the
impeller cavity so as to cooperatively define a slot (not visible in FIG. 3)
that connects the
impeller cavity 119 to the collector 116. The lower housing portion 112B also
includes a wall
120 and a shelf 122 adjacent to the edge I24L. This region of the blower 100
is described in
greater detail with respect to FIG. 7.
[0083] FIG. 4 is a perspective view of a conventional impeller 10. This
impeller 10 has a
plurality of vanes 12, 20 each having a leading edge 14 and a trailing edge
16, although vanes 20
are shorter than vanes 12 and are commonly referred to as "splitters."
Conventional vanes 12, 20
have a three-dimensional curvature with a generally uniform thickness from
leading edge 14 to
trailing edge 16, with some rounding of the outside corners and filleting of
the inside corners.
[0084] FIG. 5 is a perspective view of an exemplary impeller 160 according to
certain aspects of
the present disclosure. The impeller 160 comprises an impeller plate 162
having a shaped
surface 166 and a circular outside edge 164 that are centered about an axis of
rotation 161. In
this embodiment, there is a set of long vanes 170 that alternate with a set of
splitter vanes 171.
The portion of the long vanes 170 that is not present in the splitter vanes
171 is referred to as the
"inducer" 173. Each vane 170, 171 has an inlet edge 172, a tip 174 that is
proximate to the
outside edge 164, and a top surface 176 that is, in this example, flat in a
generally circumferential
direction about axis 161 while being curved in a generally radial direction.
The region indicated
by the dashed-line oval labeled "B" is shown in FIG. 6.
[0085] FIG. 6 is a close-up plan view of a vane tip 174 of the impeller 160 of
FIG. 5 according
to certain aspects of the present disclosure. The example vane 170 has a
leading surface 180 and
a trailing surface 182 that meet at the tip 174. The leading surface 180
comprises a first portion
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177 and a second portion 175. In this example, the second portion 175 extends
from the tip 174
with a radius R2 that is the same radius as the outside edge 164. The first
portion 177 abuts the
second portion 175 and continues with a radius RI that is smaller than R2 and
larger than the
radii conventionally used to round outside edges. In certain embodiments, the
radius RI may be
within the range of 0.03-0.20 inch. In certain embodiments, the radius RI may
be within the
range of 0.12-0.18 inch. In certain embodiments, the radius R1 may be within
the range of 0.14-
0.16 inch. In certain embodiments, the radius R1 may be approximately 0.15
inch.
[0086] Without being bound by theory, it is believed that the effect of the
radius R1 may be to
control the turbulence of the air at the tip 174 and reduce the velocity
gradient in the air flow as
the air leaves the impeller 160, compared to a conventional vane that abruptly
ends at the outside
edge with a sizable angle between the leading surface and the outside edge, as
is visible in the
impeller 10 of FIG. 4. By smoothing this transition over a larger area, e.g.
the length of the first
portion 177 and possible the second portion 175, and redirecting the air flow
direction, the
velocity gradient is reduced and the air flow may be less turbulent as the air
leaves the impeller
160 and passes through the slot 126.
[0087] Each vane 170, 171 has a centerline 179 that is coincident with and
bisects the top
surface 176 between the leading and trailing surfaces 180, 182. The vanes 170,
171 have a
common width W taken perpendicular to the centerline 179, wherein W varies
along the
centerline 179. At a common distance from the tip 174 along the centerline
179, the width W of
each vane 170, 171 will be the same, for at least the length of the splitter
vanes 171.
[0088] The shape and width of the vanes 170, 171 proximate to the second
portion 177 may be
selected to simply enable the radius to be as large as RI, compared to the
constant-thickness
vanes of a conventional impeller. In certain embodiments, the trailing surface
182 has a
minimum radius that is greater than the radius of the first portion of the
leading surface 180. In
certain embodiments, the shape and location of the trailing surface 182 may be
chosen to
cooperate with the leading surface of the adjacent vane 170, 171 to control
the pressure and/or
velocity of the air flowing between the leading and trailing surfaces 180,182.
[0089] The height of the vanes 170, 171, i.e. the distance from the shaped
surface 166 to the top
surface 176, varies from the inlet edge 172 and tip 174. In certain
embodiments, the height is
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constant from the tip 174 over the first and second portions 177, 175 of the
leading surface 180.
In certain embodiments, the shaped surface 166 has an outside portion 163 that
is proximate to
the first and second portions 177, 175 of the leading surface 180. In certain
embodiments, the
shaped surface 166 is flat and perpendicular to the axis 16 in the outside
portion 163.
[0090] FIG. 7 is a cross-section taken along section line A-A of the blower
100 of FIG. 1
according to certain aspects of the present disclosure. The arrows 101 and 102
respectively
indicate how air is drawn in through the inlet 119 and directed by the
impeller 160 into the
collector 116. The motor 120 is shown in schematic form and, in this
embodiment, the rotor (not
shown in FIG. 7) of the motor 120 is directly connected to the impeller 160.
The area indicated
by the dashed-line box "C" is discussed in greater detail with respect to FIG.
8.
[00911 FIG. 8 is an enlarged view of the area C of FIG. 7 according to certain
aspects of the
present disclosure. The cross-section of impeller 160 shows the top surface
166, a bottom
surface 167, and the outside edge 162. The upper edge 124U of the top housing
portion 112T
and the lower edge 124L of the bottom housing portion 11213 are proximate to
each other and
separated by a slot 126. In this embodiment, the edges 124U and 124L both have
a radius R4 on
an inside corner nearest to the impeller 160, with angled surfaces that extend
outward at an
included angle 174 toward the collector 116. The radius R4 improves the
efficiency of the
nozzle formed by slot 126. The radius R4 of edges 124U and 124L induces the
"Coanda effect,"
wherein a flowing gas will tend to follow a curved surface more readily than a
sharp edge, in the
gas flowing through the slot 126. This redirection of the gas flowing through
the slot 126
produces a smoother transition of flow and pressure with lower loss and
reduced audible noise.
In certain embodiments, R4 may be within the range of 0.01-0.30 inch. In
certain embodiments,
R4 may be approximately 0.020 inch.
100921 In this example, the reference line 170 is aligned with the peak of the
radius R4 of lower
edge 124L and the reference line 172 is aligned with the peak of the radius R4
of upper edge
124U. Thus, the slot 126 is defined by the reference lines 170, 172. In this
example, the shaped
surface 166 at the outside edge 162 is aligned with reference line 170, i.e.
the lower edge 124L
of the slot 126, and the top surfaces 176 of the plurality of blades 170, 171
are each aligned with
the reference line 172, i.e. the upper edge 124U of the slot 126.
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[0093] The gap between the top surface 176 and the upper inner surface 123 of
the upper
housing 112T is a path of potential backflow from the edge 162 of the impeller
160 toward the
center. Minimizing the gap 183 between top surface 176 and the upper inner
surface 123
reduces this backflow and thereby improves the pressure recovery of the blower
100. In certain
embodiments, the gap 183 may be in the range of 0.002-0.150 inch when the
impeller 160 is
stationary relative to the housing 112. In certain embodiments, the gap 183
may be in the range
of 0.005-0.050 inch. In certain embodiments, the gap 180 may be approximately
0.010 inch.
[0094] The lower edge 124L has an adjacent wall 120 with a gap 180 between the
outside edge
162 and the wall 120. In certain embodiments, the gap 180 may be in the range
of
0.0035-0.110 inch when the impeller 160 is stationary relative to the housing
112. In certain
embodiments, the gap 180 may be in the range of 0.005-0.050 inch. In certain
embodiments, the
gap 180 may be approximately 0.0073 inch. In certain embodiments, the radius
R2 of the
outside edge 162 of the impeller 160 may increase as the rotational velocity
of the impeller 160
increases and, therefore, the gap 180 may be reduced when the impeller 160 is
rotating relative to
the housing 112. In certain embodiments, the impeller 160 may rotate at a
rotational velocity of
up to 60,000 rotations per minute (rpm) relative to the housing 112 and the
gap may be reduced
to as little as 0.003 inch. As there will be a boundary layer (not visible in
FIG. 8) attached to
each of the wall 120 and the outside edge 162, reducing this gap may decrease
the portion of the
gap wherein airflow may go turbulent, e.g. the portion between the two
boundary layers, thereby
reducing the acoustic energy generated by the turbulent air.
[0095] The wall 120 connects to a shelf 122. There is a gap 182 between the
bottom surface 167
of the impeller 160 and the shelf 122 of the bottom housing portion 112B. In
certain
embodiments, the gap 182 may be less than or equal to 0.020 inch when the
impeller 160 is
stationary or moving relative to the housing 112B. In certain embodiments, the
gap 182 may be
less than or equal to 0.050 inch. In certain embodiments, the gap 182 may be
less than or equal
to 0.020 inch.
[0096] FIGS. 9A-9C are perspective views of the overmolded top housing 112T
according to
certain aspects of the present disclosure. FIG. 9A depicts a translucent view
of a layer 200 of a
sound-damping material formed so as to match the external profile of a housing
shell 210 shown
in FIG. 9B. In this example, the sound-damping layer 200 covers most of the
external surface of
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the housing shell 210 with the exception of the attachment points 212 for the
clips 114 (not
shown in FIGS. 9A-9C). FIG. 9C shows combined top housing portion 112T with
the sound-
damping layer 200 on the external surface of the housing shell 210.
[0097] In certain embodiments, the sound-damping layer 200 comprises an
elastomer, e.g. a
silicone or rubber, having poor acoustic transmissibility. In certain
embodiments, the
sound-damping layer 200 may be overmolded on the housing shell 210. In certain
embodiments,
the sound-damping layer 200 may be applied to the housing shell 210 by one or
more of the
processes of transfer molding, spraying, dipping, brushing, curtain coating,
or other manual or
automated coating application process. In certain embodiments, the sound-
damping layer 200
may comprise high-density particles, e.g. steel, that may further reduce the
transmissibility of the
sound-damping layer 200.
[0098] It can be seen that the disclosed embodiments of the blower may provide
advantages in
size, cost, performance, and reduced noise during operation. The shaping of
the leading and
trailing surfaces of the vanes near the outside edge of the impeller may
reduce the turbulence and
velocity gradient in the air flow around the tip of the vanes, thereby
reducing the acoustic noise
generated by the air flow. The small clearances between portions of the
impeller and portions of
the housing may further reduce the acoustic noise by decreasing the gaps
compared to the depth
of the boundary layers, thereby reducing the portion of the gap susceptible to
noisy, turbulent
flow.
[0099] FIG. 10 depicts a patient 1010 using an exemplary ventilation system
with a
ventilator 1100 according to certain aspects of the present disclosure. The
ventilator 1100 may
include a blower, such as the blower 100 described herein. The ventilator 1100
operates as a gas
source for providing gas to a patient (e.g., for respiration). In this
example, the ventilator system
includes a supply channel, tube, or "limb" 1104, a return or exhaust channel,
tube, or limb 1106,
a conditioning module 1108 that may, for example, warm or humidify the air
passing through the
supply limb 1104. The supply and exhaust limbs 1104, 1106 are both coupled to
a patient
interface device 1102 that, in this example, is a mask that fits over the
mouth of the patient 1010.
In other embodiments (not shown in FIG. 10), the patient interface device 1102
may include a
nasal mask, an intubation device, or any other breathing interface device as
known to those of
skill in the art.
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[00100] FIGS. 11A and 11B are front and rear views of the ventilator 1100
according to
certain aspects of the present disclosure. The ventilator 1100 has a housing
1110 with an
attached user interface 1115 that, in certain embodiments, comprises a display
and a touchscreen.
In FIG. 11A, it can be seen that the front of the housing 1110 includes a
supply port 1155 for a
supply limb, such as supply limb 1104 in FIG. 10, and a return port 1150 for
an exhaust, such as
exhaust limb 1106 in FIG. 10. The return port 1150 may be mounted over an
access door 1152
that provides access to a filter (not visible in FIG. 11A) that filters and
absorbs moisture from the
exhaled breath of the patient 1010. In certain embodiments, there may also be
a front connection
panel 1160 for connection to external instruments or a network interface
cable.
[00101] FIG. 11B shows a rear view of the ventilator 1100 with a gas inlet
adapter 1120,
an air intake port 1140, and a power interface 1130 that may include a power
plug connector and
a circuit breaker reset switch. There may also be a rear interface panel 1165
for connection to
external instruments or a network interface cable. A flow control device, such
as a flow cassette
described herein or a flow control valve described herein, may be installed
within the housing
1110 behind the gas inlet adapter 1120 and in fluid communication between an
inlet connector
1126 shown in FIG. 11B and the supply port 1155 shown in FIG. I IA.
[00102] FIG. 12 illustrates a schematic depiction of the ventilator 1100
having a control
system 305, system hardware 310, user input 315, output 320, and feedback 325.
The control
system 305 includes a ventilation control system 330 that receives user input
315. The control
system 305 includes hardware control systems that control respective hardware
components of
the ventilator 1100. For example, the hardware control systems may include a
blower control
system 335, a flow cassette control system 340, and an exhalation valve
control system 345. The
blower control system 335 controls a respective blower 350, the flow cassette
control system 340
controls a respective flow cassette 355, and the exhalation valve control
system 345 controls a
respective exhalation valve 360. The blower 350 may correspond to the blower
100 described
herein, and may be in fluid communication with the flow cassette 355 and/or
the exhalation
valve 360. For example, the blower 350 may be before or after the flow
cassette 355 or the
exhalation valve 360 in a fluid path of the ventilator 1100.
[00103] The system hardware 310 includes sensors 365 that detect
information from the
system hardware 310, for example, the blower 350, the flow cassette 355, and
the exhalation
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valve 360. The sensors 365 produce one or more feedback signals 325 that are
received by the
ventilation control system 330. The ventilation control system 330 receives
the feedback control
signals 325 and the user input 315 and sends information to an output 320. The
output 320 can
include, for example, monitoring information and alarms. The feedback control
signals 325
may also be used to provide inputs to the blower control system 335, the flow
cassette control
system 340, and the exhalation valve control system 345.
[00104] One example of feedback and control of the ventilator 1100 is
depicted in FIG.
13A, which illustrates a schematic depiction of an exhalation control feedback
system 400 that
determines an amount of gas flow 405 that is permitted to pass through an
exhalation valve 410.
The illustrated embodiment of the feedback system 400 is based on a target
pressure 420 and an
actual circuit pressure 425 (or a pressure within a line of the ventilator
1100).
[00105] As illustrated in FIG. 13A, a processor 430 receives an input
signal relating to the
actual circuit pressure 425 and compares the actual circuit pressure 425 to
the target pressure
420. Based on this comparison, the processor 430 sends a command signal 435 to
an exhalation
valve driver 440. The exhalation valve driver 440 is configured to control a
position of the
exhalation valve 410 to regulate the gas flow 405 through the exhalation valve
410. In the
illustrated embodiment, the exhalation valve driver 440 sends a control
current 445 to the
exhalation valve 410 to maintain or adjust the exhalation valve 410 to modify
or adjust the
pressure within the ventilator line.
[00106] For example, if the actual circuit pressure 425 was found to be too
high, the
processor 430 sends a command 435 to the exhalation valve driver 440 to open
the exhalation
valve 410 to reduce pressure within the ventilator line. The exhalation valve
driver 440, upon
receiving the command 435 to relieve pressure, adjusts the control current 445
to the exhalation
valve 410 to increase the opening of the exhalation valve 410 and relieve
pressure within the
ventilator line. As the control current 445 increases the opening of the
exhalation valve 410, the
processor 430 receives position feedback 450 of the exhalation valve 410 via
the exhalation
valve driver 440, such that the processor 430 is able to determine the degree
to which the
exhalation valve 410 is open.
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[00107] If the actual circuit pressure 425 input to the processor 430 was
found to be too
low, the processor 430 directs the driver 440 to adjust the control current
445 to the exhalation
valve 410 to decrease the opening of the exhalation valve 410 such that
pressure within the
ventilator line is increased. If the actual circuit pressure 425 input to the
processor 430 was
found to be at an acceptable level or within an acceptable range, the
processor 430 directs the
driver 440 to maintain the control current 445 to the exhalation valve 410 to
maintain the
position of the exhalation valve 410.
[00108] Another example of feedback and control of the ventilator 1100 is
depicted in
FIG. 13B, which illustrates a schematic depiction of an inhalation control
feedback system 401
that determines an amount of gas flow 406 that is permitted to pass through an
inhalation
valve 411. The illustrated embodiment of the feedback system 401 is based on a
target flow 421
and an actual flow 426 (or a flow within a line of the ventilator 1100). The
position feedback
may be used to determine flow, using the orifice characteristics of the valve
and generally
understood principles of fluid flow. Multiple gas types may be controlled
based on the identified
gas type (or gas id). The primary advantage of this flow measurement method is
that the need
for a separate flow sensor is eliminated and the resulting package provides
for a compact flow
delivery system.
[00109] As illustrated in FIG. 13B, a processor 431 receives an input
signal relating to the
actual flow 426 and compares the actual flow 426 to the target flow 421. Based
on this
comparison, the processor 431 sends a command signal 436 to an inhalation
valve driver 441.
The inhalation valve driver 441 is configured to control a position of the
inhalation valve 411 to
regulate the gas flow 406 through the inhalation valve 411. In the illustrated
embodiment, the
inhalation valve driver 441 sends a control current 446 to the inhalation
valve 411 to maintain or
adjust the inhalation valve 411 to modify or adjust the flow rate through the
ventilator line.
[00110] For example, if the actual flow 426 was found to be too high, the
processor 431
sends a command 436 to the inhalation valve driver 441 to close the inhalation
valve 411 to
reduce the flow rate through the ventilator line. The inhalation valve driver
441, upon receiving
the command 436 to reduce the flow rate, adjusts the control current 446 to
the inhalation valve
411 to decrease the opening of the inhalation valve 411 and reduce the flow
rate within the
ventilator line. As the control current 446 decreases the opening of the
inhalation valve 411, the
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processor 431 receives position feedback 451 of the inhalation valve 411 via
the inhalation valve
driver 441, such that the processor 431 is able to determine the degree to
which the inhalation
valve 411 is open.
[00111] If the actual flow 426 input to the processor 431 was found to be
too low, the
processor 431 directs the inhalation driver 441 to adjust the control current
446 to the inhalation
valve 411 to increase the opening of the inhalation valve 411 such that the
flow rate through the
ventilator line is increased. If the actual flow 426 input to the processor
431 was found to be at
an acceptable level or within an acceptable range, the processor 431 directs
the driver 441 to
maintain the control current 446 to the inhalation valve 411 to maintain the
position of the
inhalation valve 411.
[00112] FIG. 14 illustrates an exemplary schematic arrangement of a current
control
system 500 that illustrates some embodiments of a driver (e.g., the exhalation
valve driver 440 of
FIG. 13A or the inhalation valve driver 441 of FIG. 13B) operating to adjust a
valve 503 (e.g.,
the exhalation valve 410 or the inhalation valve 411). In the illustrated
system 500, a high
frequency source 505 generates a signal having a high frequency, and a low
frequency source
510 generates a signal having a low frequency. The high frequency signal and
the low frequency
signal are summed together, and the signal is amplified by a current amplifier
515. In some
embodiments, the current amplifier 515 is a linear current output amplifier.
The signal is then
directed to a coil 520 (e.g., a force coil) that is configured to move at
least partly within a fixed
magnetic field 525. The fixed magnetic field 525 is produced by a magnetic
field generator, e.g.,
at least one permanent magnet 530 or a separate coil (not shown).
[00113] The natural frequency of the coil 520 is such that the coil 520
responds to the low
frequency component of the combined signal by movement within or in relation
to the magnetic
field, as illustrated by arrows 535. In some embodiments, the low frequency
component is less
than about 90% of the natural frequency of the coil 520. In some embodiments,
the low
frequency component is less than about 80% of the natural frequency of the
coil 520, and in yet
further embodiments, the low frequency component is less than about 50% of the
natural
frequency of the coil 520.
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[00114] The high frequency component of the combined signal preferably has
a negligible
effect on the position of the coil 520 such that the position of the coil 520
within the magnetic
field is controlled substantially by the low frequency component. For example,
in some
embodiments, the high frequency component is more than 50% greater than the
natural
frequency of the coil 520. In some embodiments, the high frequency component
can be between
50% and about 200% greater than the natural frequency of the coil 520. In yet
additional
embodiments, the high frequency can be more than 200% greater than the natural
frequency of
the coil 520.
[00115] A detection coil 540, or a feedback coil, detects the high
frequency component of
the signal passing through the coil 520, and the detection coil 540 sends a
signal to a high
frequency feedback processor 545 that determines, based on the detection coil
540 signal, a
position of the coil 520 within the magnetic field 525. In some embodiments, a
magnitude of the
high frequency signal detected by the detection coil 540 is used to determine
the position of the
coil 520 within the magnetic field 525. In some instances, the high frequency
feedback
processor 545 also determines a velocity of the coil 520 within the magnetic
field 525 and the
high frequency feedback processor 545 sends a signal to the low frequency
source 510 for
providing feedback on the position and/or velocity of the coil 520. In some
embodiments, the
high frequency feedback processor 545 includes a position circuit 547 and a
velocity circuit 548.
[00116] The low frequency source 510 also receives input from a sensor (not
shown)
within a ventilator line relating to how an actual condition 550 (e.g.,
pressure or flow rate) within
the ventilator line compares to a target condition 555 of the ventilator line.
Based on (i) the input
relating to the comparison of actual condition 550 and the target condition
555 and (ii) the input
from the high frequency feedback processor 545 relating to the position of the
coil 520 in
relation to the magnetic field 525, the low frequency source 510 determines
whether the low
frequency signal should be modified to change the position of the coil 520 in
relation to the
magnetic field 525.
[00117] For example, if the actual condition 550 were determined to be
outside of an
acceptable range of values set by the target condition 555, the low frequency
source 510 changes
the low frequency signal to move the coil 520 within the magnetic field 525.
The coil 520 is
preferably coupled, directly (e.g., mechanically) or indirectly (e.g.,
magnetically), to a portion of
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the valve 503 that regulates flow through the valve 503. Accordingly, movement
of the coil 520
moves the portion of the valve 503 and changes an amount of gas passing
through the valve 503.
As the amount of gas passing through the valve 503 changes, the detected
condition within the
ventilator line changes, and the actual condition 550 is detected and compared
with the target
condition 555.
[00118] In some embodiments, it is advantageous to maintain a positive
pressure within
the ventilator line. For example, when the ventilator line is an exhalation
line, or exhalation
pathway, from a patient, and it is desirable to maintain a positive pressure
within the patient's
lungs relative to a local atmospheric pressure (or ambient pressure), the
target condition 555 may
include a minimum threshold pressure. When the actual condition 550 is
determined to drop
below the threshold pressure, the low frequency source 510 may be configured
to close the valve
503, such that substantially no gas from the exhalation line passes through
the valve 503. The
valve 503, in such instances, may remain closed until the actual condition 550
within the
exhalation line increases above the threshold pressure, at which time, the low
frequency source
510 receives inputs reflecting that the valve 503 should be opened, and the
source 510 changes
the low frequency signal to move the coil 520 to a position in relation to the
magnetic field 525
that corresponds to an opening of the valve 503. In some instances, upon
receiving a signal that
the actual condition 550 is above the threshold pressure, the low frequency
source 510 may
produce a signal that maintains position of the coil 520, and therefore the
valve 503, to further
increase the actual pressure within the exhalation line.
[00119] In some embodiments, it is advantageous to regulate a flow rate
within the
ventilator line. For example, when the ventilator line is an inhalation line,
or inhalation pathway,
to a patient, and it is desirable to regulate the flow rate to reach a target
volume of gas, the target
condition 555 may include a threshold time of flow rate. When the actual
condition 550 is
determined to reach the threshold time of flow rate, the low frequency source
510 may be
configured to close the valve 503, such that substantially no gas from the
inhalation line passes
through the valve 503. The valve 503, in such instances, may remain closed
until the next cycle,
at which time, the low frequency source 510 receives inputs reflecting that
the valve 503 should
be opened, and the source 510 changes the low frequency signal to move the
coil 520 to a
position in relation to the magnetic field 525 that corresponds to an opening
of the valve 503. In
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some instances, upon receiving a signal that the actual condition 550 has not
reached the
threshold time of flow rate, the low frequency source 510 may produce a signal
that maintains
position of the coil 520, and therefore the valve 503, to maintain the flow
rate through the
inhalation line.
[00120] FIG. 15A is an exemplary cross sectional view of the a valve 600A,
which may be
the exhalation valve 410 or the inhalation valve 411, and operates under the
same or similar
principles described above with respect to valve 503 depicted in FIG. 14. The
illustrated valve
600A includes a housing 605 that defines an internal chamber 610. Disposed
within the internal
chamber 610 is a coil 615 that is positioned and axially movable within or in
relation to a fixed
magnetic field generator 620. An armature 650 has a pole piece and may include
or be attached
to the coil 615. Positioned about at least a portion of the magnetic field
generator 620 is a sensor
625. In some embodiments, the sensor 625 is a detection coil that is
configured to detect high
frequency signals passing through the coil 615. The high frequency signals
detected by the
sensor 625 are used to determine a position of the coil 615 within or in
relation to the magnetic
field generator 620.
[00121] A signal is communicated from the sensor 625 regarding a position
of the coil
615, and signals are directed to the coil 615 via a flexible communication
cable 630. As the
signals directed to the coil 615 cause the coil 615 to move within the
internal chamber 610 in
relation to the magnetic field, movement of the coil 615 affects positioning
of a convoluted
diaphragm 635 and poppet 647 or seal. The poppet 647 operates as a variable
orifice of the
valve 600. Positioning of the poppet 647 with respect to the seat 645 affects
the amount of fluid
that passes through a valve having an opening 640.
[00122] Movement of the coil 615 can change a position of the sensor 625 by
being
directly coupled to the poppet 647 and moving the poppet 647 toward or away
from a seat 645,
which defines the valve orifice as the gap between the poppet 647 and seat
645. For example,
the armature 650 may be directly connected to the diaphragm 635 and/or the
poppet 647. In
some embodiments, movement of the coil 615 can change a position of the poppet
647 by being
indirectly coupled to the poppet 647. For example, a portion of the coil 615
and a portion of the
poppet 647 may be magnetically opposed or attracted to each other. In such
embodiments,
movement of the coil 615 thereby opposes or attracts the portion of the poppet
647. In a similar
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configuration to direct coupling, this indirect coupling can affect
positioning of the poppet 647 in
connection with the seat 645 of the valve without contact between the coil 615
and the poppet
647.
[00123] Although a diaphragm with a poppet are illustrated in FIG. 15A,
other types of
valve configurations may be used in connection with the described embodiments.
For example,
other valves that can be used include, but are not limited to, a flap valve, a
rotating disk valve, a
duck-billed valve, etc.
[00124] The valve 600A can also provide increased stability by damping the
moving
components of the valve 600A. As explained above, a velocity of the coil 615
can be determined
by a processor (e.g., processor 430 or 431 or high frequency feedback
processor 545), which can
include a velocity circuit that calculates a change of position with respect
to time. The velocity
can then be used to determine the desired damping. With the assumption that
the valve 600A
functions as a second order system, the damped frequency response is greater
than or equal to
about 40 Hz, and the damping coefficient that yields an under-damped or
critically damped valve
assembly. In other embodiments, additional damping such as pneumatic viscous
damping can be
incorporated into the valve 600A to further tune the valve 600 to the specific
application.
[00125] The valve 600A can include a "fail-safe" open feature in case of
loss of electrical
power, software control, or loss of all inlet gases. The valve 600A can also
be configured to
switch to the "fail-safe" open configuration when the ventilator 1100 is
turned off. On
successful completion of power on checks, the ventilator 1100 will close the
valve 600A and
normal ventilation can commence. During a ventilator 1100 "fail-safe" open
condition, the valve
600A, and other valves or ports will work in conjunction to (i) relieve
pressure from the circuit
down to ambient pressure conditions, (ii) allow ambient air to be available to
the patient for
breathing, and (iii) minimize re-breathing of gases.
[00126] FIG. 15B illustrates a valve 600B, which may be another
implementation of the
valve 600A. The valve 600B may comprise similar components as the valve 600A.
In addition,
the valve 600B comprises a front flat spring 652, and a rear flat spring 654.
The front flat spring
652 and the rear flat spring 654 provide mechanical or structural support for
the armature 650.
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In other implementations, the armature 650 may be supported by other
structures, such as
bearings.
[00127] FIG. 16 illustrates a schematic depiction of another implementation
of the
ventilator 1100 having a control system 705, system hardware 710, user input
715, output 720,
and feedback 725. The control system 705 includes a ventilation control system
730 that
receives user input 715. The control system 705 includes hardware control
systems that control
respective hardware components of the ventilator 100. For example, the
hardware control
systems may include a blower control system 735, an inflow valve control
system 740, and an
exhalation valve control system 745. The blower control system 735 controls a
respective
blower 750, the inflow valve control system 740 controls a respective inflow
valve 755, and the
exhalation valve control system 745 controls a respective exhalation valve
760. The blower 750
may correspond to the blower 100 described herein and may be in fluid
communication with the
inflow valve 755 and/or the exhalation valve 760. For example, the blower 750
may be before or
after the inflow valve 755 or the exhalation valve 760 in a fluid path of the
ventilator 1100.
[00128] The system hardware 710 includes sensors 765 that detect
information from the
system hardware 710, for example, the blower 750, the inflow valve 755, and
the exhalation
valve 760. The sensors 765 produce one or more feedback signals 725 that are
received by the
ventilation control system 730. The ventilation control system 730 receives
the feedback control
signals 725 and the user input 715 and sends information to an output 720. The
output 720 can
include, for example, monitoring information and alarms. The feedback control
signals 725 may
also be used to provide inputs to the blower control system 735, the flow
cassette control system
740, and the exhalation valve control system 745.
[00129] The inflow valve control system 740 may be similar to and operate
similarly to
the exhalation valve control system 745, which may correspond to the feedback
system 400 in
FIG. 13 or the current control system 500 in FIG. 14. The inflow valve 755 may
also be similar
to and operate similarly to the exhalation valve 760, which may correspond to
the exhalation
valve 410 in FIGS. 13 and 15, or the valve 503 in FIG. 14. Although labeled as
inflow valve
755, the inflow valve 755 may be any front end valve before the patient in a
gas flow. The
exhalation valve 760 may be any back end valve behind the patient in a gas
flow.
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[00130] In FIG. 12, a flow cassette is used, whereas in FIG. 16, a valve
control system is
used instead. A flow cassette may include a pressure measurement device for an
inlet gas, which
measures pressure differential to determine flow measurement. The flow
cassette may also
include another valve tracker that drives the flow control valve of the flow
cassette. Thus, a flow
cassette provides flow measurement and flow control.
[00131] The valve control systems described herein provide flow control
through the
variable valve opening, but also provide flow measurement. The flow
measurement can be
derived from the position of the force coil or drive coil. Thus, the valve
control systems also
provide flow measurement and flow control, similar to flow cassettes. However,
flow cassettes
may be cost prohibitive for certain applications. For example, in certain
applications, a
ventilator system with valve control systems may be less expensive to produce
than a ventilator
system with one or more flow cassettes. The valve control systems may be
different sizes, for
example one quarter of the size of the other, as needed. The two valve control
systems can work
together, with one for inspiration and one for exhalation. For example, the
inflow valve 755 may
be open and regulated until an appropriate volume of gas has flowed to the
patient. The inflow
valve 755 will then close, and the exhalation valve 760 will open, and
regulated until an
appropriate volume of gas has been exhaled by the patient.
[00132] More particularly, gas is connected to the inflow valve 755 which
starts closed,
building up high pressure. The inflow valve control system 740 commands the
inflow valve 755
to open, allowing the flow through to the patient. When inspiration starts,
the exhalation valve
760 is closed. The inflow valve control system 740 determines when to close
the inflow valve
755 based on a flow control or a pressure control. When the inflow valve 755
is closed, the
exhalation valve control system 745 commands the exhalation valve 760 to open,
allowing the
patient to breathe out. The inflow valve 755 is directed to open, and the
cycle repeats. Flow
control may be calculated by sampling, for instance, the pressure every
millisecond to make
adjustments. Based on the position of the drive coil, the pressure can be
calculated. The
pressure is continuously monitored to adjust the position of the drive coil
until a target flow is
reached. The calculations may factor in ambient pressure, gas composition, gas
temperature
changes, downstream pressure changes, inlet pressure changes, etc. The
calculations may further
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correct for standard conditions. By continuously monitoring pressure and
adjusting the position
of the drive coil, the exhalation valve 760 allows the patient to exhale
without difficulty.
[00133] Although the flow control devices described herein may be used in
connection
CPAP therapy, other embodiments, particularly embodiments used on the front
end of the
ventilator, are not limited to CPAP therapy. The flow control devices
described herein may be
utilized at any point along a flow path of a ventilator, respirator, or other
similar device. In
addition, the flow control devices may be used in other fluid devices,
particularly fluid devices
which measure and/or regulate fluid flow, and are not limited to respiration.
[00134] FIG. 17 shows a flowchart 800 of controlling a flow valve, such as
the valve 503.
At block 810, a high frequency signal and a low frequency signal is sent to a
drive coil, such as
the coil 615. The low frequency signal causes the drive coil to move within a
fixed magnetic
field, such as the fixed magnetic field generator 620. The moved drive coil
causes a movable
part, such as the poppet 647 or seal, to adjust a valve orifice of the valve,
such as the opening
640. At block 820, the high frequency signal in the moved drive coil is
detected. At block 830,
a velocity of the drive coil is determined based on the detected high
frequency signal. At block
840, the low frequency signal is modified based on the determined velocity of
the drive coil. For
example, the velocity signal may be injected into the low frequency source for
the purpose of
dampening.
[00135] The block 830 may be expanded into several operations, denoted by
the dotted
lines in FIG. 17. At block 832, a delay between the high frequency signal and
the detected high
frequency signal may be determined. FIG. 18 shows a sample space 900. A high
frequency
signal 910, which may be a high frequency current from the high frequency
source 505, is
compared to a detected high frequency signal 920, which may be a high
frequency current
detected in the drive coil after the drive coil moves. A delay 930 between the
signals may be
proportional to the position of the drive coil. Thus, at block 834, the
position of the drive coil is
determined based on the delay. At block 836, the velocity of the drive coil is
determined based
on the position of the drive coil. With the velocity determined at block 836,
at block 840, the
low frequency signal may be modified based on the determined velocity of the
drive coil to, for
example, control dampening of the drive coil.
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[00136] A ventilator such as the ventilator 1100 may utilize an adapter
described herein to
facilitate connections.
[00137] FIGS. 19-20 are front and back perspective views of an exemplary
fluid inlet
adapter 2100 according to certain aspects of the present disclosure. In FIG.
19, the fluid inlet
adapter 2100, also referred to herein as "the adapter 2100," comprises a body
2110 with two
inlets 2120, 2130 that are configured to respectively mate with connectors
2020, 2030 that are
connected to two different fluid sources. In certain embodiments, the two
connectors 2020 and
2030 may comprise different configurations comprising attributes such as
shape, the presence or
absence of thread, keys, etc. Example connector configurations are shown in
FIGS. 25-28. A
handle 2140 is movably coupled to the body 2110 and comprising an access
control
element 2142. In certain embodiments, the access control element 2142 is a
paddle extending
from a shaft 2141 that is, in this example, perpendicular to the body 2110.
The handle 2140 is
shown in FIG. 19 in a latched position, wherein the access control element
2142 is positioned in
front of inlet 2130, thereby preventing a user from connecting a connector
2030 to the inlet 2130.
In certain embodiments, the access control element 2142 is disposed in front
of the inlet 2130.
In certain embodiments, the access control element 2142 is disposed proximate
to the inlet 2130,
e.g. adjacent to the side of the inlet 2130, so as to interfere with the
attachment of a
connector 2030 to the inlet 2130 and substantially prevents connection to the
inlet 2130 when the
adapter 2100 is in the position shown in FIG. 19. The inlet 2120 is fully
accessible in this
position of the adapter 2100 and a user may connect a connector 2020 to the
inlet 2120. The
body 2110 may include one or more keying holes 2111 that engage pins, posts,
or other keying
features (not shown in FIG. 19) of the connectors 2020, 2030.
[00138] FIG. 20 depicts the back of the adapter 2100. A center plane 2101
is defined
relative to the body 2110 and bisects the body 2110. There is an alignment
feature 2112
extending from the body 2110 that is centered on the center plane 2101. There
are two ports
2116 that are identical in form that are coupled to the body 2110 and
symmetrically disposed on
opposite sides of the center plane 2101. The adapter 2100 has a first
position, as shown in FIG.
20, and a second position that is rotated 180'from the first position with
respect to the plane of
symmetry. Positions of the adapter 2100 are discussed in greater detail with
respect to FIGS. 23
and 24. The adapter 2100 also comprises first and second coupling ports 2116
that are
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symmetrically located on opposite sides of the center plane 2101 on a back
side of the
body 2110. The first and second coupling ports 2116 are in respective fluid
communication with
the first and second inlets 2120, 2130. In certain embodiments, the coupling
ports 2116 may be
respectively aligned with the first and second inlets 2120, 2130. In certain
embodiments, the
coupling ports 2116 may be respectively offset from the first and second
inlets 2120, 2130.
[00139] It
can be seen in FIG. 20 that the handle 2140 comprises a latching pin 2144 that
is disposed within a securing feature, for example slot 2114 formed in the
alignment feature
2112. The latching pin 2144, in this example, extends outward from the portion
of the shaft 2141
that extends beyond the bottom of the body 2110. The function of the pin
latching 2144 and the
method by which the handle 2140 secures the adapter 2100 to a device, for
example a ventilator
(not shown), is discussed in greater detail with respect to FIGS. 22A-22B.
[00140] FIG.
21A is a cross-sectional side view of the exemplary fluid inlet adapter 2100
and a device 2010 according to certain aspects of the present disclosure. The
device 2010 has a
housing 2052 with, in this example, a docking station 2050 having an alignment
slot 2066 that is
configured to accept the alignment feature 2112. In this example, there is a
recess 2062 adjacent
to the alignment slot 2066 that is configured to accept an end of the handle
2140. A latching
slot 2064 extends laterally from the recess 2062 and is configured to engage
the pin 2144 when
the handle 2140 is rotated such that the pin extends from the alignment
feature 2112, as is
discussed in greater detail with respect to FIGS. 22A-22B.
[00141] The
housing 2052 comprises a fluid passage 2080 is configured to accept a flow
of a fluid. In certain embodiments, the device 2010 is a ventilator and the
fluid passage 2080
connects to a blower (not shown) that pumps the fluid from fluid passage 2080
to a patient as is
generally known to those of skill in the art and not repeated herein. The
fluid passage 2080 is
positioned relative to the alignment slot 2066 such that one of the coupling
ports 2116 will be at
least partially disposed within the fluid passage 2080 when the adapter 2100
is secured to the
device 2010 in either a first or second position. FIG. 21A depicts the example
adapter 2100
secured to the docking station 2050 in the first position, wherein the
coupling port 2116 that is in
fluid communication with inlet 2120 is also at least partially disposed within
and in fluid
communication with the fluid passage 2080. In the second position (not shown
in FIG. 21A), the
adapter 2100 is upside down from the position shown in FIG. 21A such that the
coupling
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port 2116 that is in fluid communication with inlet 2130 is also at least
partially disposed within
and in fluid communication with the fluid passage 2080. In certain
embodiments, the coupling
ports 2116 may have a sealing feature 2118, for example an 0-ring, which is
configured to
detachably and sealingly mate with the fluid passage 2080. The housing also
comprises a blind
recess 2054 that accepts the un-used coupling port 2116. The docking location
2050 may have a
recess 2056 configured to accept the body 2110 such that the front of the body
2110 is flush with
the surface of the housing 2052. In certain embodiments, the docking location
2050 may also
have a recess 2070 position under a keying hole 2111. The recess 2070 may
provide clearance
for a keying feature of a mating connector or may provide a retention
function.
[00142] FIG. 21B is a cross-sectional side view of the exemplary adapter
2100 of FIG.
21A mated with the docking location 2050 of the housing 2052 according to
certain aspects of
the present disclosure. It can be seen that the lower coupling port 2116 is
partially disposed
within the fluid passage 2080 and the upper coupling port 2116 is partially
disposed within the
blind recess 2054.
[00143] FIGS. 22A-22B depict the position of the handle 2140 in exemplary
unlatched
and latched positions according to certain aspects of the present disclosure.
FIG. 22A depicts the
position of the handle 2140 while in an "unlatched" position suitable for
insertion of the
alignment feature 2112 into the alignment slot 2066 of the docking station
2050. The pin 2144 is
positioned completely within the slot 2114 so as not to interfere with the
alignment slot 2066.
Once the adapter 2100 is fully seated in the docking station 2050, the handle
2140 can be turned
to the position shown in FIG. 22B.
[00144] FIG. 22B depicts a "latched" position with handle 2140 rotated so
as to engage
pin 2144 in latching slot 2064. In this position of handle 2140, the access
control element 2142
is disposed in front of the inlet 2130 thereby obstructing access to the inlet
2130 so as to
discourage connection of a connector 2030 to the inlet 2130 while the adapter
2100 is secured to
the device 2010 in this position.
[00145] FIGS. 23 and 24 depict an exemplary inlet adapter 2100 configured
to accept fluid
from two different sources 2020, 2030 according to certain aspects of the
present disclosure.
FIG. 23 depicts the adapter 2100 configured to enable inlet 2120 to allow a
connector 2020 (not
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shown in FIG. 23) while blocking connection to the inlet 2130. It can be seen
that the machine-
detectable indicator 2150 is positioned in a first position, e.g. on the near
side of alignment
feature 2112.
[00146] FIG. 24 depicts the adapter 2100 reversed in orientation and
configured to allow
inlet 2130 to accept a connector 2030 (not shown in FIG. 24) while blocking
connection to the
inlet 2120. It can be seen that when the adapter 2100 is disposed in this
position, which is the
reverse of the position of FIG. 23, that the machine-detectable indicator 2150
is positioned in a
second position, e.g. on the far side of alignment feature 2112, that is also
the reverse of FIG. 23.
[00147] With respect to the positions of the machine-detectable indicators
2150 in FIGS.
23 and 24, the device 2050 may have a first sensor (not shown in FIG. 23)
positioned so as to
detect the presence of the sensor in the position of FIG. 23 and a second
sensor positioned so as
to detect the presence of the sensor in the position of FIG. 24. The use of
two sensors may
provide a positive indication of the position of the adapter 2100 and,
therefore, a positive
indication of which gas is being provided.
[00148] FIGS. 25-28 depict example connector configurations according to
certain aspects
of the present disclosure. The adapter 2100 may comprise inlets that are
configured to accept
one of these types of connectors. FIG. 25 depicts an "Ohmeda style" gas
connection 2200
wherein the gas-specific configuration of the connector is accomplished by one
or more notches
2220 on the outlet face 2210 and a pin 2230 on the adaptor. The notches 2220
and pins 2230 may
vary in position and/or size based on the gas required.
[00149] FIG. 26 depicts a "Chemetron style" gas connection 2300 wherein the
gas-specific configuration of the connector is accomplished by the position
and shape of the
latching hole 2320 on the outlet face and alignment tabs 2330 that mate with
recesses 2340. The
latching hole 2320 will vary in position and shape based on the gas required.
[00150] FIG. 27 depicts a "Diameter Index Safety System (DISS) style" gas
connection
2400 wherein the gas-specific configuration of the connector is accomplished
by gas-specific
threads disposed on a barrel 2410. The thread diameter and adaptor nipple size
may vary based
on the gas required.
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[00151] FIG. 28 depicts a "Schrader style" gas connection 2500 wherein the
gas-specific
configuration of the connector is accomplished by geometric indexing, i.e.
each gas has a unique
shape and size of the barrel 2510.
[00152] It can be seen that the disclosed embodiments of the inlet adapter
provide a
reliable means of configuring a device, such as a ventilator, to accept only
one of a possible
variety of gases. While the disclosed embodiment of the adapter has two inlets
and accepts gas
through one inlet while blocking the other inlet, other embodiments of the
adapter may have
three or more inlets and may be configured to accept gas through more than one
of the three or
more inlets. In addition, the machine-detectable indicator that is disclosed
as a magnet herein
may be any machine-readable element, for example a barcode or 2D matrix
positioned to be read
by a camera or scanner when the adapter is configured in a certain position.
[00153] FIGS. 29-33 show implementations of adapters having one inlet. FIG.
29 shows
an adapter 3100. The adapter 3100 has a housing 3105, an inlet 3101 extending
through the
housing 3105, a machine-detectable or machine-readable indicator 3120, and a
latching
component 3110. The inlet 3101 has a first end 3102 for connecting to a
particular fluid source,
and a connector 3103 for connecting to a flow control device 3200 (see in FIG.
30), which may
be a flow cassette or other valve system. The latching component 3110, which
may be a
threaded nut that can be screwed by hand, is configured to interface with a
threaded connector
3210 of the flow control device 3200. The latching component 3110 includes a
groove 3112.
The machine-readable indicator 3120 may be a tab which includes magnet
positions 3122A,
3122B, 3122C, and 3122D, which may hold one or more magnets in a magnet
configuration
3125. In some embodiments, one or more magnet positions 3122A, 3I22B, 3122C,
and 3122D
may not hold any magnet. Although the magnet positions 3122A-D may be in a
linear
arrangement, in other implementations, other arrangements may be used.
[00154] FIG. 30 shows another adapter 3300. The adapter 3101 has a magnet
configuration 3126, which may have magnets in magnet positions 3122B and
3122C. The
magnets may be embedded within the machine-readable indicator 3120. Also seen
in FIG. 30,
an adapter 3400 has a magnet configuration 3127, which may have magnets in
magnet positions
3122B and 3122D.
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[00155] The magnet configurations may be detected by a sensor 3220 of the
flow control
device 3200. The sensor 3220 may include magnet sensors 3222A, 3222B, 3222C,
and 3222D,
which may correspond to the magnet positions 3122A-D. FIG. 31 shows the
adapter 3100
connected to the flow control device 3200, which may be secured by tightening
the latching
component 3110. The sensor 3220 aligns with the machine-readable indicator
3120. The sensor
3220 is configured to detect the magnet configurations of adapters. The magnet
configurations
correspond to specific fluid sources. For example, the magnet configuration
3126 may
correspond to heliox, and the magnet configuration 3127 may correspond to
oxygen. The inlet
3101 may be configured for connection to the corresponding fluid source. By
detecting the
magnet configuration, the flow control device 3200 can identify the fluid
passing through the
flow control device 3200. After identifying the fluid, the various processors
of the ventilator
1100 may use parameters corresponding to the identified fluid for further
calculations as
described herein.
[00156] FIG. 32 shows the adapter 3100 without the latching component 3110.
The
housing 3105 includes a first protrusion 3106, and a second protrusion 3107.
The housing 3105
also includes a first pin 3116, and a second pin 3118. The first and second
pins 3116 and 3118
are configured to interface with the groove 3112 of the latching component
3110, allowing the
latching component 3110 to rotate freely without being separated from the
housing 3105. The
threaded connector 3210 includes a first notch 3212 and a second notch 3214.
[00157] FIG. 33 further shows the adapter 3100 and the flow control device
3200. A first
width 3108 of the first protrusion 3106 corresponds to a first width 3213 of
the first notch 3212.
A second width 3109 of the second protrusion 3107 corresponds to a second
width 3215 of the
second notch 3214. The first protrusion 3106 is configured to fit into the
first notch 3212, and
the second protrusion 3107 is configured to fit into the second notch 3214.
Because the first and
second widths are different, the adapter 3100 can only fit into the threaded
connector 3210 in one
orientation, to mitigate incorrect insertions. In addition, a distance 3104
between the inlet 3101
and the machine-readable indicator 3120 corresponds to a distance 3221 between
the threaded
connector 3210 and the sensor 3220 such that the sensor 3220 can detect the
machine-readable
indicator 3120. The machine-readable indicator 3120 may be properly aligned
with the sensor
3220 when the latching component 3110 is fully tightened. When the machine-
readable
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indicator 3120 is not properly detected by the sensor 3220, or the magnet
configuration is
unknown (e.g., a magnet is missing or in the wrong magnet position), an alarm
condition may
occur. In addition, when the adapter 3100 is not properly or fully connected,
pressurized gas
may leak, causing an audible notification to the operator.
[00158] For example, the connector 3103 may be configured to have a length
such that the
connector 3103 provides fluid communication with the flow control device 3200
at an
intermediate portion along the threaded connector 3210's path when being
connected. The
length of the connector 3103 extends such that there may be fluid
communication even when the
latching component 3110 is not fully engaged. Upon removal of the adapter
3100, for instance
by disengaging the latching component 3110, an audible hissing sound may
inform the operator
that the supply must be turned off and/or that the adapter 3100 should be
fully removed from the
source to limit complications associated with improper removal procedures.
[00159] The use of multiple adapters 3100 allow a single flow control
device 3200 to
connect to various fluid sources, rather than having a flow control device for
each possible fluid
source. Reducing the number of flow control devices may reduce the size of the
ventilator. The
multiple adapters may be tethered to the ventilator in order to prevent
misplacement of the
adapters.
[00160] The systems and methods described herein for measuring flow rates
and
compensating for the composition of the gas or gas mixture as well as the
temperature of the
measured gas provides increased accuracy compared to flow measurements made
within
conventional ventilators.
[00161] Turning to FIGS. 11A-B, a flow cassette 4200 may be installed
within the
housing 1110 behind the gas inlet adapter 1120 and in fluid communication
between the inlet
connector 1126 shown in FIG. 11B and the supply port 1155 shown in FIG. 11A.
[00162] FIG. 34 is a block diagram of an exemplary flow cassette 4200
according to
certain aspects of the present disclosure. The flow cassette 4200 may
correspond to the flow
cassette control system 340 described above. The flow cassette 4200 includes
an inlet 4222 that
is configured to sealingly mate with an input flow channel, for example a
coupler 4122 of the gas
inlet adapter 4120. The gas inlet adapter 4120 also has an inlet connector
(not shown in FIG. 34)
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that is fluidly connected to the coupler 4122. Various breathing gases and gas
mixtures are
associated with individually unique connector types, sizes, and
configurations, wherein the
association is generally recognized in the medical industry. Each gas inlet
adapter 4120 has one
or more inlet connectors that are adapted to respectively accept a connector
that is unique to a
certain type of gas or gas mixture. The number and placement of magnets 4124
are uniquely
associated with the inlet connector that will be coupled to the inlet of the
flow cassette 4200
when that gas inlet adapter 4120 is installed in a ventilator and thereby
mated with the flow
cassette 4200. In certain embodiments, the gas inlet adapter 4120 may be
configured to accept
one or more of a standard composition of ambient air, a pure oxygen, and a
heliox gas mixture.
[00163] The inlet 4222 is fluidly connected to a passage 4223 that runs
through the flow
cassette 4200 to an outlet 4232 that is configured to sealingly mate with an
output flow channel
of the ventilator 4100 that, for example, leads to the supply limb 4104. In
this example
embodiment, there are several elements disposed along the passage 4223,
including a check
valve 4260, a filter 4264, a porous disk 4410 and a valve 4300. In certain
embodiments, some of
these elements may be omitted or arranged in a different order along the
passage 4223. In this
embodiment, the flow cassette 4200 also includes a Hall effect sensor 4258
configured to detect
the number and placement of the magnets 4124 of the gas inlet adapter 4120. By
comparing the
detected number and placement of the magnets 4124 to stored information
associating the
number and placement of the magnets 4124 with gases that will be accepted by
the inlet
connector that is coupled to the inlet of the flow cassette 4200, the
processor 4252 can
automatically determine what gas will be provided through the gas inlet
adapter 4120 as installed
in the ventilator 4100. In other embodiments, the gas inlet adapter 4120 may
include another
type of indicator, for example a machine-readable element, that is associated
with the
configuration of the gas inlet adapter 4120 and the flow cassette 4200 may
include a sensor that
is capable of reading the machine-readable element and thereby automatically
detecting the
configuration of the gas inlet adapter 4120.
[00164] The flow cassette 4200 includes a flow sensor 4400 that has a flow
restriction
4410 that, in this example, is a porous disk disposed in passage 4223 such
that all gas flowing
through the passage 4223 must pass through the porous disk 4410. The flow
sensor 4400 also
includes an upstream pressure sensor 4420A and downstream pressure sensor
4420B with gas
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passages 4424 from the sensors to sensing ports 4421A and 4421B disposed in
the passage 4223
on upstream and downstream sides, respectively, of the porous disk 4410. There
is also a
temperature sensor 4270 that has a temperature sensing element 4271 disposed
in the passage
4223. In conjunction with the knowledge of which gas is flowing through the
porous disk 4410,
derived from the configuration of the gas inlet adapter 4120 as indicated by
the magnet 4128 and
sensed by the Hall effect sensor 4258, and the knowledge of the temperature of
the gas, as
measured by the temperature sensor 4270, the pressure drop can be used to
determine the true
flow rate, sometimes referred to as "the compensated flow rate," of the gas
that is passing
through the porous disk 4410.
[00165] The pressure drop across the porous disk 4410 is related in a
monotonic way to
the rate of gas passing through the porous disk 4410. The porous disk 4410 is
characterized as to
its flow resistance characteristics with a selection of gases and gas mixtures
at a standard
temperature. Without being bound by theory, certain gases, such as helium,
have a smaller
molecular size and pass more easily through the thickness of the porous disk
4410 compared to a
gas, such as nitrogen, with a larger molecule. Thus, a certain pressure drop
will indicate a first
flow rate for a small-molecule gas and a second, lower flow rate for a large-
molecule gas. Gas
mixtures will tend to have flow rates that reflect the percentage composition
of the gases that
make up the gas mixture. In certain embodiments, the pressure drops of certain
predetermined
medical gases and gas mixtures are specifically characterized for the porous
disk 4410 and stored
in a look-up table contained in the memory 4254 of the electronics module
4250. The
temperature of a gas also affects the pressure drop for a given flow rate of
that gas flowing
through the porous disk 4410. In certain embodiments, the effect of the gas
temperature is also
characterized for the porous disk 4410 and stored in the memory 4254. In
certain embodiments,
the characterization of the flow characteristics of the porous disk 4410, also
referred to herein as
"compensation parameters," are combined for gas type and temperature in a
single look-up table.
Those of skill in the art will recognize that such compensation parameters may
be stored in other
forms, for example equations that include scaling parameters, to enable
conversion of a raw
pressure drop measurement into an accurate flow rate.
[00166] The flow cassette 4200 includes an electronics module 4250. In
certain
embodiments, the conversion of the raw pressure measurements by pressure
sensors 4420A,
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4420B into a pressure drop measurement is accomplished in a separate pressure
sensing
electronics 4422 and provided to a flow sensor processor 4252. In certain
embodiments, the
pressure sensing electronics 4422 may provide the processor 4252 with
individual pressure
signals for pressures that are upstream and downstream of the porous disk
4410. In certain
embodiments, there may also be a front connection panel 4160 for connection
to, for example,
external instruments, sensors, or sensor modules. In certain embodiments, the
pressure sensors
4420A, 4420B may provide the raw signals directly to the processor 4252. In
certain
embodiments, the pressure sensors 4420A, 4420B may include conversion
circuitry such that
each sensor 4420A, 4420B provides a pressure signal directly to the processor
4252.
[00167] In certain embodiments, the temperature sensor 4270 provides a
signal that
includes a temperature to the pressure sensing electronics 4422. In certain
embodiments, the
temperature sensor 4270 provides this temperature signal directly to the
processor 4252. In
certain embodiments, the temperature sensing element 4271 may be connected
directly to the
pressure sensing electronics 4422 or to the processor 4252. In certain
embodiments, the
temperature sensor 4270 may be configured to sense the gas temperature over a
range of
temperatures of at least 5-50 C. In certain embodiments, the temperature
sensor 4270 may be
configured to sense the gas temperature over a range of temperatures of at
least 5-50 C.
[00168] The processor 4252 is connected to the memory 4254 and an interface
module
4256 as well as the sensors 4270, 4420A, and 4420B. The various drive,
sensing, and processing
functions of these sensors 4270, 4420A, and 4420B may be accomplished in
various different
modules, such as the processor 4252 and pressure sensing electronics 4422,
depending on the
particular design and layout of the flow cassette 4250 without departing from
the scope of this
disclosure. For example, a processor 4252 may be configured to provide a
supply an electrical
current directly to the temperature sensing element 4271 and to directly
measure a voltage drop
across the temperature sensing element 4271 without the need for intervening
electronics. All
functions disclosed herein may be accomplished in the block elements of FIG.
34 as described or
in alternate blocks and the blocks depicted in Fig. 34 may be combined or
divided without
departing from the scope of this disclosure.
[00169] The memory 4254 is configured to store operating instructions for
the processor
4252 and data that may include calibration data for the sensors 4258, 4270,
4420A, and 4420B.
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The data may also include information, as discussed above, such as equations
or look-up tables
to use the two pressure measurements from pressure sensors 4420A and 4420B and
the
temperature measurement from the temperature sensor 4270 to determine a flow
rate through the
porous disk 4410. In certain embodiments, the memory comprises non-volatile
memory such as
magnetic disk, a solid-state memory, a flash memory, or other non-transient,
non-volatile storage
device as known to those of skill in the art.
[00170] The processor 4252 is also operatively coupled to the valve 4300
and is capable of
actuating the valve 4300. The interconnection of the processor 4252 with the
other elements as
shown in FIG. 34 may be accomplished by direct connection via any technology
known to those
of skill in the art, for example twisted-pair wires or fiber-optic cables, or
via a network
connection with microprocessors embedded in the other elements. The interface
module 4256
may include signal transceivers for wired or wireless communication with other
devices within
the ventilator 4100 or may connector to an external interface, such as the
rear interface panel
1165 shown in FIG. 11B, to communicate with devices external to the ventilator
1100.
[00171] FIG. 35A depicts an exemplary flow cassette 4200 according to
certain aspects of
the present disclosure. The flow cassette 4200 has a body 4210 with an inlet
end 4220 and an
outlet end 4230. At the inlet end 4220, there is the inlet 4222 that is
configured to sealingly mate
with a coupler 4122 (not shown in FIG. 35A) of a gas inlet adapter 4120. The
inlet end 4220
may also include locating features 4226, for example protruding pins, that
align the gas inlet
adapter 4120 to the inlet 4222 and a mating face 4224 that provides a
reference surface for the
mated gas inlet adapter 4120. A solenoid 4240 is attached to the body
proximate to the outlet
end 4230 to drive a pressure control valve (not visible in FIG. 35A) disposed
within the
body 4210. The electronics module 4250 is attached, in this embodiment, to the
top of the
body 4210. The details of the electronics module are discussed in greater
detail with respect to
FIG. 34.
[00172] FIG. 35B is a cross-section of the flow cassette of FIG. 35A
according to certain
aspects of the present disclosure. The dashed-line box 4400 indicates the
elements that make up
the flow sensor 4400, which is discussed in greater detail with respect to
FIGS 34 and 35C. The
passage 4223 that connects the inlet 4222 and outlet 4232 is visible in the
cross-section of
FIG. 35B, with the porous disk 4410 disposed within the passage 4223.
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[00173] FIG. 35C is an enlarged view of a portion of FIG. 35B showing the
exemplary
flow sensor 4400 according to certain aspects of the present disclosure. In
this example, the
pressure sensors 4420A, 4420B are disposed within the package of the pressure
sensing
electronics 4422 and connected to the passage 4223 by gas passages 4424
leading to sensing
ports 4421A and 4421B. The temperature sensing element 4271 is exposed to the
interior of the
passage 4223 and therefore in contact with the gas within the passage 4223.
Seals 4426, in this
example a pair of 0-rings, provide a gas-tight seal between the housing 4210
and the tube
extensions 4428 for the gas passages 4424 and a feed-through 4429 for the
temperature sensing
element 4271.
[00174] FIG. 36 is a flow chart of an exemplary flow measurement process
4500
according to certain aspects of the present disclosure. The process 4500
starts in step 4510 by
determining which gas or gas mixture, for example oxygen or heliox 70/30, will
be flowing
through the flow sensor 4400. In step 4515, the gas pressures upstream and
downstream of the
flow restriction 4410 are measured and a pressure drop across the flow
restriction 4410 is
calculated in step 4520. In step 4525, the processor 4252 calculates an
uncompensated flow rate
based at least partially on the pressure drop. The temperature of the gas
flowing through the
flow sensor 4400 is measured in step 4530 and in step 4535 the processor 4252
loads information
from the memory 4254 that may include compensation parameters related to the
flow sensor
4400. The processor 4252 calculates a compensated flow rate using the
retrieved compensation
parameters in step 4540 and provides this compensated flow rate, for example
to a processor of
the ventilator 1100, in step 4545. Step 4550 is a decision point that checks
whether a "stop"
command has been received, in which case the process 4500 branches along the
"yes" path to the
end and terminates. If a "stop" command has not been received, the process
4500 branches
along the "no" path back to step 4515 and measures the pressures and
temperature. The process
4500 will loop through the steps 4515-4550 until a "stop" command is received.
[00175] In summary, it can be seen that the disclosed embodiments of the
flow sensor
provide an accurate measurement of a gas flow rate in a compact and modular
form. The
accuracy of the flow rate may be improved by compensating for one or more of
the gas
temperature and the gas composition. This compensation may be accomplished
through prior
experimental calibration of the particular flow restriction, e.g. porous disk,
or calculations based
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on gas flow theory. The modular form enables this subsystem to be
independently tested and
calibrated as well as simplifying assembly and replacement.
[00176] It is advantageous to provide a modular flow cassette that provides
accurate flow
measurements of a variety of gases and gas mixtures over a range of
temperatures and flow rates.
[00177] Turning to FIGS. 11A-B, flow cassette 5200, similar to flow
cassette 4200, may
be installed within the housing 1110 behind the gas inlet adapter 1120 and in
fluid
communication between the inlet connector 1126 shown in FIG. 11B and the
supply port 1155
shown in FIG. 11A.
[00178] FIG. 37 is a block diagram of an exemplary flow cassette 5200
according to
certain aspects of the present disclosure. The flow cassette 5200 includes an
inlet 5222 that is
configured to sealingly mate with an input flow channel, for example a coupler
5122 of the gas
inlet adapter 5120. The gas inlet adapter 5120 also has an inlet connector
5126 that is fluidly
connected to the coupler 5122. Various breathing gases and gas mixtures are
associated with
individually unique connector types, sizes, and configurations, wherein the
association is
generally recognized in the medical industry. Each gas inlet adapter 5120 has
one or more inlet
connectors 5126 that are adapted to respectively accept a connector that is
unique to a certain
type of gas or gas mixture. The gas inlet adapter 5120 may include one or more
magnets 5124
wherein the number and placement of magnets 5124 are uniquely associated with
the inlet
connector 5126 that will be coupled to the inlet 5222 of the flow cassette
5200 when that gas
inlet adapter 5120 is installed in a ventilator 1100 and thereby mated with
the flow cassette 5200.
In certain embodiments, the gas inlet adapter 5120 may be configured to accept
one or more of a
standard composition of ambient air, a pure oxygen, and a heliox gas mixture.
[00179] The inlet 5222 is fluidly connected to a passage 5223 that runs
through the flow
cassette 5200 to an outlet 5232 that is configured to sealingly mate with an
output flow channel
of the ventilator 1100 that, for example, leads to the supply limb 1104 in
FIG. 10. In this
example embodiment, there are several elements disposed along the passage
5223, including a
check valve 5260, a filter 5264, a porous disk 5410 and a valve 5300. In
certain embodiments,
some of these elements may be omitted or arranged in a different order along
the passage 5223.
These elements are discussed in greater detail with respect to FIGS. 39A and
398. In this
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embodiment, the flow cassette 5200 also includes a Hall Effect sensor 5258
configured to detect
the number and placement of the magnets 5124 of the gas inlet adapter 5120. By
comparing the
detected number and placement of the magnets 5124 to stored information
associating the
number and placement of the magnets 5124 with gases that will be accepted by
the inlet
connector that is coupled to the inlet of the flow cassette 5200, the
processor 5252 can
automatically determine what gas will be provided through the gas inlet
adapter 5120 as installed
in the ventilator 1100. In other embodiments, the gas inlet adapter 5120 may
include another
type of indicator, for example a machine-readable element, that is associated
with the
configuration of the gas inlet adapter 5120 and the flow cassette 5200 may
include a sensor that
is capable of reading the machine-readable element and thereby automatically
detecting the
configuration of the gas inlet adapter 5120.
[00180] The flow cassette 5200 includes an electronics module 5250. In
certain
embodiments, the electronics module 5250 includes a temperature sensor 5270
that has a
temperature sensing element 5271 disposed in the passage 5223. The electronics
module 5250
also includes pressure sensors 5420A and 5420B that are respectively connected
through
passages to ports 5421A and 5421B in the passage 5223 that are disposed on
opposite sides of
the porous disk 5410.
[00181] The electronics module 5250 also includes a flow cassette processor
5252 that is
connected to a memory 5254 and an interface module 5256. The processor 5252 is
also coupled
to the sensors 5258, 5270, 5420A and 5420B and is configured to receive
signals from each
sensor that are associated with the measured parameter of each respective
sensor. The memory
5254 is configured to store operating instructions for the processor 5252 and
data that may
include calibration data for the sensors 5258, 5270, 5420A, and 5420B. The
data may also
include information such as equations or look-up tables to use the two
pressure measurements
from pressure sensors 5420A and 5420B to determine a flow rate through the
porous disk 5410.
In certain embodiments, additional sensors, e.g., a barometric pressure
transducer, outside the
ventilator 1100 may be used to correct the measured flow for surrounding
conditions. The
processor 5252 is also operatively coupled to the proportional valve 5300 and
is capable of
actuating the valve 5300. The interconnection of the processor 5252 with the
other elements as
shown in FIG. 37 may be accomplished by direct connection via any technology
known to those
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of skill in the art, for example twisted-pair wires or fiber-optic cables, or
via a network
connection with microprocessors embedded in the other elements. The interface
module 5256
may include signal transceivers for wired or wireless communication with other
devices within
the ventilator 1100, for example a central processor (not shown in FIG. 37),
or may connect to an
external interface, such as the rear interface panel 5165 shown in FIG. 11B,
to communicate with
devices external to the ventilator 1100. Interface 5256 may be configured to
accept both power
and communication signals and, in certain embodiments, may include one or more
voltage
converters to provide power to the module.
[00182] FIGS. 38A-38B depict an exemplary flow cassette 5200 according to
certain
aspects of the present disclosure. The flow cassette 5200 has a body 5210 with
an inlet end 5220
and an outlet end 5230. The inlet end 5220 includes an inlet 5222 that is
configured to sealingly
mate with a coupler 5122 (not shown in FIG. 38A) of the gas inlet adapter
5120. The inlet end
5220 may also include locating features 5226, for example protruding pins,
that align the gas
inlet adapter 5120 to the inlet 5222 and a mating face 5224 that provides a
reference surface for
the mated gas inlet adapter 5120. A solenoid 5240 is attached to the body
proximate to the outlet
end 5230 and is discussed in greater detail with respect to FIG. 39A. The
electronics
module 5250 is attached, in this embodiment, to the top of the body 5210. The
details of the
electronics module are discussed in greater detail with respect to FIG. 37.
[00183] FIG. 38B is a reverse-angle view of the flow cassette 5200 that
shows the outlet
5232 and the seal 5234, in this example two 0-rings, that are arranged at the
outlet end 5230.
The outlet end 5230 is configured to sealingly mate with other gas passages
(not shown in FIG.
38B) within the ventilator 1100.
[00184] FIG. 39A is a cross-section of the flow cassette 5200 of FIGS. 38A-
38B
according to certain aspects of the present disclosure. An enlarged view of
the region indicated
by the dashed-line box labeled "A" is shown in FIG. 39B.
[00185] The dashed-line box 5400 indicates elements of the flow sensor
5400, including
the pressure sensors 5420A, 5420B and a flow restriction 5410 that, in this
example, is a porous
disk. The porous disk 5410 provides a known flow resistance that creates a
pressure drop across
the porous disk 5410 that varies with flow rate and may be calibrated for one
or more gases or
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gas mixtures. An actual pressure drop can be determined by measuring the
pressures upstream
and downstream of the porous disk 5410 with the pressure sensors 5420A and
5420B and
determining the pressure difference between the pressure measurements. In
conjunction with the
knowledge of which gas is flowing through the porous disk 5410, derived from
the configuration
of the gas inlet adapter 5120 as indicated by the magnet 5128 and sensed by
the Hall Effect
sensor 5258, and the knowledge of the temperature of the gas, as measured by
the temperature
sensor 5270, the pressure drop can be used to determine the true flow rate,
sometimes referred to
as "the compensated flow rate," of the gas that is passing through the porous
disk 5410. The
flow sensor 5400 may also include pressure sensing electronics 5422 that
filter and condition the
signals from the pressure sensors 5420A, 5420B and may convert the signals to
digital form.
[00186] The dashed-line box 5300 indicates elements of the proportional
valve 5300,
including the solenoid 5240 and a plug 5320 that fits into a bore 5310 of the
passage 5223. In
certain embodiments, the plug 5320 and bore 5310 form an on-off fluid valve
and the solenoid
5240 is configured to either fully retract or fully extend the plug 5320 so as
to open or close the
valve 5300. In certain embodiments, the plug 5320 and bore 5310 form a
variable-flow orifice
and the solenoid 5240 is configured to adjustably position the plug 5320 with
respect to the
bore 5310 through a feedback control loop operative within the flow cassette
processor 5252 that
is operatively coupled to the solenoid 5240. In certain embodiments, the flow
cassette processor
5252 may actuate the solenoid 5240 so as to provide a determined flow rate, as
sensed by the
flow sensor 5400, or a determined pressure at the outlet 5232, as sensed by
pressure sensor
5420B.
[00187] FIG. 39B is an enlarged view of a portion of FIG. 39A according to
certain
aspects of the present disclosure. Gas entering the inlet 5222 passes to a
check valve 5260 that is
configured to allow flow through the passage 5223 toward the outlet 5232 while
resisting flow in
the opposite direction. The check valve 5260 includes, in this embodiment, a
rigid structure 5261
having a plurality of through holes 5263 with a flexible disk 5262 attached to
the rigid structure
5261 at the center. Gas flowing from the inlet towards the outlet 5232 (not
visible in FIG. 39B)
creates a pressure on the upstream side of the flexible disk 5262 that pushes
the flexible disk
5262 away from rigid structure 5261, thereby uncovering the through holes 5263
and allowing
the gas to flow through the check valve 5260. When the pressures on both sides
of the check
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valve 5260 equalize, the flexible disk 5262 returns to sealing contact with
the rigid structure
5261, thereby covering the through holes 5263 and preventing gas from flowing
through the
check valve towards the inlet 5222.
[00188] After passing through the check valve 5260, gas passes through a
filter 5264 that,
in this embodiment, is formed as a hollow cylinder that is held in place by a
cap 5266 having
legs 5267 that contact the rigid structure 5261 of the check valve 5260 so as
to retain the cap
5266 and filter 5264 in place. Gas passes around the outside of the cylinder
and then passes
inward through the filter 5264 to the hollow center and then flows out of the
filter 5264. In
certain embodiments, the filter 5264 comprises a mechanical filter configured
to trap particulates
above a determined size. In certain embodiments, the filter 5264 comprises one
or more
chemical filters, for example an activated charcoal or a desiccant, that are
configured to absorb
certain materials such as water or odors. In this embodiment, the temperature
sensing element
5271 is disposed proximate to the filter 5264 and flush with the wall of the
passage 5223.
[00189] FIG. 40 is a flow chart of an exemplary configuration process 5500
according to
certain aspects of the present disclosure. The process 5500 starts in step
5510 by installing a
flow cassette 5200 in a ventilator 1100. In step 5515, the user determines
which gas or gas
mixture, for example oxygen or heliox 70/30, will be provided to the patient,
selects the proper
gas inlet adapter 5120, and attaches the gas inlet adapter 5120 to the
ventilator 1100 in the proper
configuration such that the correct connector of the gas inlet adapter 5120
for the determined gas
or gas mixture is coupled to the flow cassette 5200. As the gas inlet adapter
5120 includes a
magnet 5124 that indicates the type of gas being provided by the specific gas
inlet adapter 5120
as installed in the ventilator 1100, the processor 5252 of the flow cassette
5200 can automatically
determine in step 5520 which gas or gas mixture is being provided by sensing
the magnet 5124
through the Hall Effect sensor 5258, as discussed with respect to FIG. 37. In
step 5525, the
processor 5252 loads information from the memory 5254 that may include
calibration and/or
compensation parameters related to the flow sensor 5400. The ventilator 1100
is now configured
for use. After the user connects a breathing circuit with a patient, generally
as shown in FIG. 10,
the user starts the ventilator 1100 in step 5530.
[00190] During operation of the ventilator 1100, the flow cassette 5200
measures the
pressures on both sides of the porous disk 5410 and the temperature of the gas
passing through
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the flow cassette 5200 in step 5535 using the flow sensor 5400 and temperature
sensor 5270,
respectively, as described with respect to FIGS. 37 and 39A. In step 5540, the
processor 5252
applies the compensation and calibration information downloaded in step 5525
to calculate the
actual flow rate of the gas and provides this flow rate information in step
5545, for example to a
processor in the ventilator 1100. Step 5550 is a decision point that branches
depending on
whether a "stop" command has been received. If the user has provided a "stop"
command, the
process 5500 branches along the "yes" path to the end and terminates. IF the
user has not
provided a "stop" command, the process 5500 branches along the "no" path back
to step 5535
and measures the pressures and temperature. The process 5500 will loop through
the
steps 5535-5550 until a "stop" command is received.
[00191] In summary, it can be seen that the disclosed embodiments of the
flow cassette
consolidate certain mechanical functions, such as backflow prevention and
filtration, and the
sensing of certain parameters, such as flow rate, in a compact and modular
form. In certain
embodiments, the flow cassette includes electronics that process the raw
measurements using
internally stored compensation and calibration data and provide more accurate
values of the
sensed parameters. In certain embodiments, the flow cassette may be configured
to provide
either a determined pressure or a determined flow rate of the supply gas at
the outlet. The
modular form enables this subsystem to be independently tested and calibrated
as well as
simplifying assembly and replacement.
[00192] FIG. 41 illustrates a ventilator 6000, which may correspond to the
ventilator 1100.
The ventilator 600 comprises various component parts, which may each be
removed with a
common tool, such as a Philips screwdriver. The ventilator 600 comprises a
blower 6050, a first
flow valve 6055, a second flow valve 6060, a filter chamber 6070, and
insulated flow path 6075,
and a flow combiner 6080. The component parts may be designed to fit within
specific interior
dimensions of the ventilator 6000. Each of the component parts may be removed
and replaced
with alternative component parts, which may have similar dimensions as the
part being replaced.
[00193] The blower 6050, which may correspond to the blower 350 and/or the
blower
750, may pull in gas. The blower 6050 may include a HEPA filter. The first
flow valve 6055,
which may correspond to the 02 flow cassette 355 and/or the inflow valve 755,
receives another
gas, such as pressurized oxygen from a gas supply. The flow combiner 6080 may
combine the
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gases from the blower 6050 and the first flow valve 6055. The flow combiner
6080 may connect
to the patient for an inspiration phase. The flow combiner 6080 may include a
flow sensor for
detecting flow to the patient, a safety valve which may open to protect the
patient during an
overpressure condition, and an occluder valve which blocks inflow to allow a
clinician to
measure inspiratory effort by the patient.
[00194] For the patient's expiration phase, the patient's expiration flow
may be connected
to the filter chamber 6070. The filter chamber 6070 may include a chamber, and
may also be
configured to accumulate condensation from expiration. The filter chamber 6070
may include or
be connected to a heater for warming the expiration and reducing condensation.
The expiration
flow may continue through the insulated flow path 6075, which includes
insulation to prevent the
expiration from cooling down and causing condensation. The expiration flow
continues to the
second flow valve 6060, which may correspond to the exhalation valve 360
and/or the exhalation
valve 760.
[00195] This description is provided to enable any person skilled in the
art to practice the
various aspects described herein. While the foregoing has described what are
considered to be
the best mode and/or other examples, it is understood that various
modifications to these aspects
will be readily apparent to those skilled in the art, and the generic
principles defined herein may
be applied to other aspects. Thus, the claims are not intended to be limited
to the aspects shown
herein, but is to be accorded the full scope consistent with the language
claims, wherein
reference to an element in the singular is not intended to mean "one and only
one" unless
specifically so stated, but rather "one or more." Unless specifically stated
otherwise, the terms
"a set" and "some" refer to one or more. Pronouns in the masculine (e.g., his)
include the
feminine and neuter gender (e.g., her and its) and vice versa. Headings and
subheadings, if any,
are used for convenience only and do not limit the invention.
[00196] It is understood that the specific order or hierarchy of steps in
the processes
disclosed is an illustration of exemplary approaches. Based upon design
preferences, it is
understood that the specific order or hierarchy of steps in the processes may
be rearranged.
Some of the steps may be performed simultaneously. The accompanying method
claims present
elements of the various steps in a sample order, and are not meant to be
limited to the specific
order or hierarchy presented.
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[00197] Terms such as "top," "bottom," "front," "rear" and the like as used
in this
disclosure should be understood as referring to an arbitrary frame of
reference, rather than to the
ordinary gravitational frame of reference. Thus, a top surface, a bottom
surface, a front surface,
and a rear surface may extend upwardly, downwardly, diagonally, or
horizontally in a
gravitational frame of reference.
[00198] A phrase such as an "aspect" does not imply that such aspect is
essential to the
subject technology or that such aspect applies to all configurations of the
subject technology. A
disclosure relating to an aspect may apply to all configurations, or one or
more configurations. A
phrase such as an aspect may refer to one or more aspects and vice versa. A
phrase such as an
"embodiment" does not imply that such embodiment is essential to the subject
technology or that
such embodiment applies to all configurations of the subject technology. A
disclosure relating to
an embodiment may apply to all embodiments, or one or more embodiments. A
phrase such an
embodiment may refer to one or more embodiments and vice versa.
[00199] The word "exemplary" is used herein to mean "serving as an example
or
illustration." Any aspect or design described herein as "exemplary" is not
necessarily to be
construed as preferred or advantageous over other aspects or designs.
[00200] All structural and functional equivalents to the elements of the
various aspects
described throughout this disclosure that are known or later come to be known
to those of
ordinary skill in the art are expressly incorporated herein by reference and
are intended to be
encompassed by the claims. Moreover, nothing disclosed herein is intended to
be dedicated to
the public regardless of whether such disclosure is explicitly recited in the
claims. No claim
element is to be construed under the provisions of 35 U.S.C. 112, sixth
paragraph, unless the
element is expressly recited using the phrase "means for" or, in the case of a
method claim, the
element is recited using the phrase "step for." Furthermore, to the extent
that the term "include,"
"have," or the like is used in the description or the claims, such term is
intended to be inclusive
in a manner similar to the term "comprise" as "comprise" is interpreted when
employed as a
transitional word in a claim.
[00201] This specification describes example aspects of the subject
technology, which
may include at least the following concepts:
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[00202] Concept 1. A ventilator comprising: a blower comprising: a
housing defining
an impeller cavity; an impeller plate disposed within the impeller cavity and
comprising an
outside edge; and one or more vanes disposed on the impeller plate and
comprising a leading
surface and a trailing surface connecting at a tip; and a flow control device
comprising: a fixed
magnetic field; a drive coil configured to move within the fixed magnetic
field in response to a
low frequency signal and configured to receive a high frequency signal; a
detection coil adjacent
the drive coil and configured to detect the high frequency signal in the drive
coil, the detected
high frequency signal corresponding to a position of the drive coil; and a
processor coupled to
the high frequency source and the low frequency source and configured (i) to
receive the
detected high frequency signal form the detection coil and (ii) to adjust the
low frequency signal
to move the drive coil, wherein the blower is in fluid communication with the
flow control
device.
[00203] Concept 1 may or may not provide that the leading surface comprises
a first
portion abutting a second portion, the first portion extends from the tip with
a first radius, the
second portion extends from the tip with a second radius, the first radius is
smaller than the
second radius.
[00204] Concept 2. The ventilator of Concept 1, wherein the blower is
before the flow
control device in a fluid path of the ventilator.
[00205] Concept 3. The ventilator of Concept 1, wherein the blower is
after the flow
control device in a fluid path of the ventilator.
[00206] Concept 4. The ventilator of Concept 1, further comprising a
sensor
configured to provide sensor information of the blower and the flow control
device, and a
ventilation control system configured to send the sensor information to the
flow control device.
[00207] Concept 5. The ventilator of Concept 1, further comprising a
flow cassette in
fluid communication with the blower.
[00208] Concept 6. The ventilator of Concept 1, further comprising a
fluid inlet
adapter configured to removably connect to the flow control device.
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[00209] Concept 7. The ventilator of Concept 1, wherein the one or more
vanes
comprises a top surface between the leading and trailing surfaces, the one or
more vanes
comprises a centerline bisecting the top surface between, and a width measured
perpendicular to
the centerline varies along the centerline.
[00210] Concept 8. The ventilator of Concept 7, wherein each of the one
or more
vanes have the same width along respective centerlines such that at a distance
from the
respective tip along the respective centerline, the width of each vane is the
same.
[00211] Concept 9. A ventilator comprising: a flow cassette comprising:
a fluid
passage terminating at an inlet and an outlet; a temperature sensor disposed
within the fluid
passage and configured to detect a temperature; a flow rate sensor disposed
within the fluid
passage and configured to detect a flow rate; and a processor configured to
determine a
compensated flow rate based on the temperature and the flow rate; and a fluid
inlet adapter
comprising: a first inlet end configured to connect to a fluid source; a
second inlet end
configured to removably connect to the inlet of the flow cassette; a latching
component
configured to secure the fluid inlet adapter to the flow cassette; and a
machine-readable indicator
for identifying the fluid source.
[00212] Concept 9 may or may not provide that the temperature sensor is
disposed within
the fluid passage, that the flow rate sense is disposed within the fluid
passage, or that the cassette
includes a processor configured to determine a compensated flow rate based on
the temperature
and the flow rate.
[00213] Concept 10. The ventilator of Concept 9, wherein the machine-
readable
indicator comprises one or more magnets.
[00214] Concept 11. The ventilator of Concept 10, wherein the ventilator
comprises a
sensor configured to detect a configuration of the one or more magnets.
[00215] Concept 12. The ventilator of Concept 9, wherein the second inlet
end of the
fluid inlet adapter comprises a threaded nut.
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[00216] Concept 13. The ventilator of Concept 12, wherein the inlet of the
flow cassette
comprises a threaded connector configured to interface with the threaded nut.
[00217] Concept 14. The ventilator of Concept 9, wherein the flow cassette
comprises a
valve disposed within the fluid passage and configured to provide a selectable
flow restriction.
[00218] Concept 15. The ventilator of Concept 9, further comprising a flow
control
device comprising: a drive coil configured to move in response to a low
frequency signal; a
detection coil configured to detect a position of the drive coil based on a
high frequency signal; a
flow control device processor configured to receive the high frequency signal
and modify the
low frequency signal; and a valve orifice defining a variable opening, the
variable opening
adjustable based on the position of the drive coil.
[00219] Concept 16. The ventilator of Concept 15, wherein the fluid inlet
adapter
comprises a threaded nut configured to interface with the threaded connector
of the flow control
device.
[00220] Concept 17. A ventilator comprising: a flow sensor comprising: a
fluid passage;
a flow restriction disposed within the fluid passage such that a fluid passing
through the fluid
passage must pass through the flow restriction; a first pressure sensor
coupled to a first end of the
fluid passage and configured to detect a first pressure; a second pressure
sensor coupled to a
second end of the fluid passage and configured to detect a second pressure,
such that the flow
restriction is between the first and second pressure sensors; a temperature
sensor coupled to the
fluid passage and configured to detect a temperature; and a flow sensor
processor configured to
determine a compensated flow rate based at least on the first pressure, the
second pressure, and
the temperature.
[00221] Concept 18. The ventilator of Concept 17, further comprising a
fluid inlet
adapter comprising a machine-readable indicator for identifying a fluid source
and an inlet in
flow communication with the flow sensor.
[00222] Concept 19. The ventilator of Concept 18, wherein the flow sensor
processor is
further configured to receive an identification of the fluid based on the
machine-readable
indicator and determine the compensated flow rate based at least on the
identified fluid.
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[00223] Concept 20. The ventilator of Concept 17, further comprising a
blower in fluid
communication with the flow sensor, the blower comprising: an impeller plate;
and one or more
vanes disposed on the impeller plate and comprising a leading surface and a
trailing surface
connecting at a tip, wherein the leading surface comprises a first portion
abutting a second
portion, the first portion extends from the tip with a first radius, the
second portion extends from
the tip with a second radius, the first radius is smaller than the second
radius.
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