Note: Descriptions are shown in the official language in which they were submitted.
WO n~/067~R ~ Q ~ ~, PCT/US91/0749'~
1-- .
: LOW PRESS~RE CHECK VALVE FOR
ARTIFICIAL RESPIRATION DEVICES
Cross-Reference to Related ~plications
This application is a continuatio~ of Sexial No.
599,316, filed October 17, 1990, which is a continuation-in-
part of application Serial No. 468,424, filed January 2~,
1990.
Backqround of_the Invention
The present invention relates generally to a flow
regulation apparatus, and more particularly, to a one-way
check valve which will open at ~ery low pre~sures to allow
high flow rates in a first direction and which will close to
prevent flow in a second direction.
One requirement of one-way flow valves, such as
the type used as check valves in positive crankcase
ventilation systems for internal combustion engines, is that
the valves must offer little resistance to fluid flow in one
direction but will completely stop fluid flow in the
opposite direction. A valve which is commonly used for this
purpose is a poppet valve which comprises an axially movable
? valve member which is typically biased toward a valve seat
by a helical spring. This type of valve suffers from the
problem of requiring numerous structural elements to
maintain the alignment of the movable valve member and to
provide the biasing force to close the valve. In addition,
the weight of the movable valve member results in thi~
member having too much inertia to respond quickly to sudden
changes in direction of the fluid flow at low pressures~
Another valve which is known in the art for
limiting flow in one direction and providing a high flow
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WO 92/067~ r~ ) PCr/US91/S~7499 .
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rate is the umbrella valve. In the umbrella valve, the
movable valve member is formed of a flexible material and
ha~ a generally curved cross-section. Hoop stre~se~ in the
radially outer portions of the valve member produce the
S spring force biasing the valve closed which must be overco~e
to open the valve. Thus, umbrella valves are designed to
initially open at a small predetermined pressure and
subsequently open further to provide a large flow rate with
an increase in pressure.
In other applications, such as valves u~ed in
artificial respiration devices, a duckbill check valve may
be used in co~bination with a diaphragm member to forcibly
convey air to a patient from an air bag, while preventing
exhaled air from ~eing returned to the bag. In such an
application, the valve must also be capable of preventing
back flow of fluids such as vomit. Known respirator val~es
typically produce too much resistance to the flow from the
bag to the patient, which in turn creates excessive back
pre~sure within the bag such that attending personnel
applying squeezing force to the bag will tire quickly. In
addition, respiration devices incorporating duckbill valves
often produce an o~jectionable honking noise.
While known checlc valves axe satisfactory for many
applications, the ability of known valves to respond at low
pressures typically decreases as the size of the valve and
the volume of fluid flow conducted by the valve i5
increased. Thus, there exists a need for a valve which is
capable of permitting high fluid flo~ rates at very low
pres~ures. In addition, there exists a need for a valve
which will open and close q~ickly in response to changes in
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direction of the fluid flow and which will not collapse when
subjected to high pressures in a reverse flow condit1on.
Further, there is a need for a valve which ie
capable of quiet operation while providing high flo~ rates
at very low pressures and which may be incorporated into
conventional structure for artificial respiration devices.
Summary of the Invention
The present invention is a valve assembly for
allowing high fluid flow rates at a low pressure in a first
direction and for preventing fluid flow at high pres~ures in
a second opposite direction.
The valve as~embly comprises a housing which ~ay
have a tubular shape having inlet and outlet portions. The
inlet and outlet portions are adapted to telescopingly fit
within each other for enclosing a flow regulator assembly
within the housing.
The flow regulator assembly lncludes a ~lexible
elastic element having a rim portion, a hub portion, and
connecting members extending rom the hub portion to the rim
portion such that the rim, hub and connecting members define
apertures through the elastic element.
The rim of the elastic element includes a raised
bead portion on one surface thereof on the outlet side of
the valve assembly. The outer edge of the rim is rigidly
supported by the housing. A thin disk made of an inelastic
relatively inflexible material such as plastic is ~pported
by the hub portion of the elastic element and has a diameter
which is slightly greater than the diameter defined by the
raised bead portion on the rim of the elastic element. In
addition, the housing includes a raised lip portion located
W~9~/067~ PCr/US9l/$)74~9
--4--
on the inlet side of the elastic element such th~t when a
- pressure is applied from the outlet portion toward the inlet
portion of the housing, the disk, which normally rest~ upon
the bead portion at the outlet side of the elastic element,
will be forced firmly onto the bead portion and the raised
lip will support the elastic element and prevent it from
moving.
When a fluid flow o~curs from the inlet to the
outlet side of the housing, the disk is lifted away frorn the
bead portion of the elastic element, thereby flexing the
connecting members such that the fluid flows through the
apertures in the elastic element and around the edges of -the
disk to pass out through the outlet portion of the housing.
In an alternative embodiment, the raised bead
portion may be located on the disk for engaging an opposing
surface on the rim of the elastic element and thereby
forming a seal for preventing fluid flow as described above.
Thus, the valve of the present invention provides ~
a light movable disk element which presents a large surface S
area to pressure differentials occurring on opposite ~ides
of the valve, such that small pressure differentials within
the valve result in quick opening and closing movements of
the disk.
In addition, the conne~ting members supporting the
disk provide a flexible support means for the disk while
presenting a minimum restriction to the flow through the
elastic elemen-t such that large fluid flows may be obtained
when the valve is open.
In another embodiment of ~he invention, the above-
described flow regulator assembly 7 S incorporated into the
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W092/06728 .~1Q,~'~ PCT/~S91/1~7~99
: -5-
diaphragm structure of an artif.icial respiration device. In
this embodiment of the invention, the regulator assembly is
provided for preventing back f low of gases to an air supply
bag, whilP also being movable with the diaphragm to permit
exhaled gases to escape through vent holes in the housing of
the artificial respiration device.
; Other objects and advantages of the invention will
be apparent from the following descripti.on, the accompanying
drawings and the appended claims.
Description_of the Drawinqs
: Fig. 1 is a perspective exploded view of a
preferred embodiment of the one-way check valve of the
present invention;
Fig. 2 is an elevational view of a cross sect.ion
15 - along line 2--2 in Fig. 1;
Fig. 3 is an elevational view similar to Fig. 2 in
which the valve is shown open for moderate flow;
~ig. 4 is an elevational Yiew similar to Fig. 2
showing an alternative embodiment of the present invention;
20 and
Fig. 5 is an elevational view in croqs-section of
an alternative embodiment in which the one-way check valve
is incorporated into an artificial respiration device.
Description of the Preferred Embodiment
The valve assembly of the present invention,
generally designated 10, includes a housing formed of an
inlet portion 12 and an outlet portion 14. The inlet and
outlet portions 12, 14 may be formed as tubular members and
are joined together to house a substantially circular
regulator assembly 16. The inlet portion 12, outlet portion
WO'~/067~8 ` ``. "~ rCT/US91/0749~
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14 and regulator assembly 16 are formed as substantially
symmetrical elements about the longitudinal axis 18.
Referring to Figs. 1-3, the regulator assembly 16
include~ a flexible element 20 formed of an elastic material
and is preferably formed of an elastomeric material such as
rubber. The flexible element 20 has a substantially
circular rim portion 22, a hub portion 24, and connecting
- ~embers 26 extending radially from the hub portion 24 to the
rim portion 22. The rim, hub and connecting members 22, 24, :
26 define apertures 27 in the flexib~e element 20 for
pa3~age of fluids therethrough. The ri~ portion 22 is
formed with a first substantially planar side 28 facing
: toward the outlet portion 14 and an opposing second
substantially planar side 30 and radially spaced inner and
outer surfaces 32 and 34, respectively~
The rim 22 further includes a bead portion 36
which extends axially from the first ~ide 28. The bead
portion 36 is a continuous substantially circular raised
element and is positioned between the inner and outer
: 20 surfaces 32, 34 and defines an outer diameter 38 where the
bead 36 joins the rim 22 at a point on the bead 36 which is
;; radially distal from the hub 24.
A substantially circular foot portion 40 extends
axially from the ~econd side 30 of the rim 22 and i~ located
adjacent to the outer sur~ace 34 thereof. The foot portion
40 includes an inner wall 42 which define~ an inner diameter
thereof where the foot portion 40 joins the rim portion 22.
~he inner diameter of the foot portion i~ sub~tantially
equal to the outer diameter 38 of the bead portion 36. The
fo~t portion 40 further includes a flange portion 44 whl~h
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extends radially beyond the outer surface 34 of the rim 22
to define an outer foot ~urface 460
The regulator assembly 16 further includes a
substantially circular relatively inflexible or ri~id disk
: 5 48 which i5 preferably formed of a thin lightweight and
inelastic material such as plastic. The disk 48 includes
first and second substantially planar surfaces 50 and 52 and
has a diameter slightly greater than the outer diameter 38
of the bead portion 36 such that the second surface 52 ~ay
engage the bead portion 36 in spaced relation to the first
surface 28 of the rim 22 and thereby form a seal between the
- disk 48 and the flexible element 20.
: The hub 24 of the flexible element 20 include~
means defining a hole 54 therethrough for receiving a rod
li member 56 which projects from the second surface 52 of the
;/ disk 48 and which is located substantially centrally on the
disk 48. TAe rod member 56 includes a generally conically
shaped enlarged portion 58 which is formed with a diameter
larger than that of the rod member 56 and the hole 54 such
that the member 58 acts to hold the rod 56 in place within
the hub 24~ In addition, a substantially circular ramp
portion 60 surrounds the rod 56 ad~acent to the disk 48 and
extends from the hole 54 in the hub 24 to the second surface
52 of the disk 48. The height of the ramp 60 in the axial
direction is preferably equal to the height of the bead
portion 36 and acts to space the hub 24 from contacting the
second surface 52 of the disk 48.
The inlet portion 12 of the housing includes a
side wall 61 and a flange 62 which extends radially
outwardly from the wall 61. A first substantially circular
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092~0~72~ AJ 1 ~J ~ P~ r/~S~1 /n749? -
lip 64 extends axially from a radially outer edge of the
flange 62 and a second substant.ially circular lip 66 extends
axially from the flange 62 at a location between the wall 61
and the firi~t lip 64. The second lip 66 extends from the
flange 62 a lesser distance than the first lip 64 and a
radially outer surface 68 of the second lip 66 defineq an
outer diameter which is substantially equal to the inner
diameter defined by the surface 42 of the foot portion 40.
In addition, the first lip 64 includes an inner surface 70
which defines an inner diameter substantially equal to the
diameter defined by the outer surface 46 of the foot 40 such
that a groove is formed between the first and i~econd lip~
64, 66 for receiving the foot portion 40 of the flexible
element 20 and wherein the second lip 66 acts as a i~upport
for the se;cond surface 30 of the rim portion 22.
The outlet portion 14 of the housing includes a
wall 72 and a flange 7~ which extends radially outwardly
from the wall 7~. A substantially circular lip 76 extends
axially from a radially outer edge of the flange 74 and
includes an outer wall 78 which defines a diameter which is
slightly smaller than the diameter defined by the wall 70 of
the lip 64 such that the lip 76 of the outlet portion 14 may
be received in telescoping relation within the first lip 64
of the inlet portion 12.
One or more stop members 80 in the form of rod
shaped projections extend from the flange 74 of the outlet
portion 14 at a location between the wall 72 and the lip 76
and are located on a diameter whic~ is smaller than that of
the ~isk 43. The stops 80 are equally spaced from one
another and extend from the flange 74 a lesser distance than -
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~'On2/067'~ ,~., PCT/IJS9t/0749
that of the lip 76. Alternatively, a single ~top may be
located centrally of the outlet portion 14 and supported by
thin supporting members extending radially inwardly from the
wall 72, such that the single stop is directed toward the
disk 48.
The lip 76 of the outlet portion 14 engages the
flange 44 of the foot portion 40 such that the foot portion
40 is held in position between the outlet portion lip 76 and
the inlet portion flange 62, thereb~ form7ng a seal between
the rim and the housing.
In operation, as may be best seen in Figs. 2 and
3, the disk 48 and hub 24 form a lightweight unit supported
for movement by the connecting members 26 wherein the disk
48 is normally in engagement with the bead portion 36 of the :,
flexible element 20 to form a seal therebetween. In
:addition, when a greater fluid pressure is applied through
the outlet portion 14 than through the inlet portion 12, -the
disk 48 is further forced into engagement with the bead 36
such that a strong seal preventing fluid flow is formed
; 20 between the disk and bead portions.
When a greater fluid pressure is applied through ~'
the inlet portion 12 than through the outlet portion 14, the
fluid forces the disk 48 to move toward the outlet portion ,
14 and out of engagement with the bead portion 36 along a
line substantially parallel to the longitudinal axis 18 such
that the fluid may flow through the apertures 27 bet~een the
connecting members 26 and around the outer edge of the disk
48 and then through the pas~age defined by the tubular wall
72.
WO 9~/Ot~7~ 7 P~r/us()l/n749~
1 o -
As may be seen in Fig. 3, the flexible element 20
deflects primarily at the connect:ing members 26 when the
disk 48 and the hub 24 to which i.t is connected are forced
toward the outlet portion 14. As the disk 48 i5 moved
toward the outlet portion 14, it approaches the stops 80
which act to space the disk 48 from the flange 74 to
po~itively limit the movement of the disk 48 and thereby
prevent damage to the flexi.ble element 20 resulting from
overstretching the connecting members 26, as well as ensure
that fluid flow will continue around the edges of the disk
48 and the upper surface 5~ thereof.
It should be apparent that by using a disk as the
actuating member for the valve of the present invention, a
large surface area is presented to pressure differentials
occurring on opposite sides of the valve, such that the disk
is capable of being actuated by very low forward flow
pressures.
In addition, it should be apparent that as a
result of the disk 48 seating on the bead 36 at the outer
~upported edge of the flexible element 20, such that check - --
pressures are transmitted from the disk 48 to the supporting
lip 66 along a~line which is substantlally parallel to the
longitudinal axis 18, a positive ~eal is provided while
enabling the regulator assembly to withstand e~tre~ely high ~;
check pressures without danger of the valve elements
collapsing and thereby allowing reverse fluid flows through
the valve.
Further, by constructing the disk 4a as a thin
member formed of a lightweigh:t ~aterial, the weight of the
moving element of the valve is kept to a minimum, thereby
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~'~9~/067~ PCT/~'S~/07~99
ensuring that the valve may be actuated quickly upon changes
in direction of the fluid flow and that the valve will
function properly regardless of the orientation of the valve
assembly.
In a practical application of the valve, such as
within a positive crank case ventilation system for an
internal combustion engine, the regulator assembly portion
of the valve may be constructed having approximately an inch
diameter and the stops may be positioned such that the disk
undergoes a movement of approximately 40 thouRandths o an
inch to open the valve. The pre~sure at which the valve
will open may be controlled by altering the height of the
bead portion 36 or alternatively, changing the length of the
rod member 56 to vary the amount of preload present for
biasing the disk 48 into contact with the bead portion 36.
It should be noted that other embodiments of this
valve may be formed which function in the same manner as the
above-described valve structure. Fig. 4 shows an
alternative embodiment in which the elements which are
unchanged from the previous embodiment are identified with
the same reference numerals as that embodiment. -
In the embodiment shown in Fig. 4, a disk 82
similar to the disk 48 of the previous embodiment is
provided and includes a lower surface 84 having a
substantially circular raised bead 86 extending therefrom
toward the surface 28 o~ the rim 22 which is now formed
without a bead. The bead 86 o~ the present embodiment is
formed with substantially the same diameter as the bead 36
of the pre~iou6 embodiment.
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WO 9~/06ï'S ~ ; PC~/US91/0749~)
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In addition, the flexible element 20 is provided
with a hub 88 which extends beyond the plane of the surface
28 a distance approxi~ately equal to the axial height of the
bead 86 on the disk 82. An elongated extension 90 extends
S axially from the hub 88 and terminates in a generally
conically-shaped enlarged end 92. The extension 90 extend~
through a hole in the disk 82 and the enlarged end 9~ and
- hub B8 cooperate with opposing surfaces of the disk 82 to
- hold the disk 82 in place on the flexible element 20.
10 The hub 88 and extension include a hole 94
- extending therethrough in a longitudina1 direction. The
hole 94 further lightens the movable portion of the valve as
well as facilitates compression of the extension 90 and
enlarged end 92 for insertion into the disk 82.
Further, other methods of attaching the disk and
the flexible element together have been contemplated. For
example, these elements may be held together by means of a
pop-rivet or other fastener means. Although such attachment
means may add to the weight of the movable member, they may
be satisfactory for certain applications of the valveO
Referr1ng to Fig. 5, the elements forming the
regulator assembly of the check valve are shown incorporated
into an artificial respiration device. In this embodiment,
- a diaphragm asQembly 100 is mounted within a housing 102 for
an artificial respiration de~ice, and the diaphragm assembly
~ 100 and housing 102 are preferably formed symmetrically
;~ about a central axis 103.
The housing 102 includes a first opening 104
formed in a housing half 112 and a ~econd opening 106 formed
in another housing half 110. The housing half 110 includes
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-13-
a radially outwardly extending flange portion 109 and a lip
portion 111 which extends substantially perpendicularly from
the flange portion 109.
Similarly, the housing half 112 includes a
: 5 radially extending flange portion 113 and a lip portion 115
which extends substantially perpendic~larly from the flange
portion 113. The lip portions 111, 115 mate with each other
to hold the diaphragm assembly 100 in position within the
housing 102.
- 10 The flange portion 109 of the hou~ing half 110
includes means defining a plurality of vent pa~a~e~ or
: holes 10~ which are disposed radially inwardly from the lip
portion 111 and radially outwardly from the ~econd opening
. 106.
The diaphragm assembly includes a diaphragm member
~- 114 formed of an elastomeric material and extending around a
peripheral interior portion of the housing 102. A flange
portion 117 extending around an outer peripheral portion of
the diaphragm member 114 provide~ means for po3itively
positioning and holding the diaphragm assembly 100 in place
7 between the two housing halves 110, 112. The diaphra~m
: member 114 includes at least one convolution 116 which
pro~ides increased flexibility for movement of the diaphragm
114. As may be seen in Fig. 5, the flange portion 117 i~
located radially outwardly from the convolution 116, and the
convolution 116 and flange portion 117 are substantially
` aligned with the axial position of the first and second
regulator portions with respect to the central axis 103
The diaphragm assembly 100 furthe~ includes a
regulator assembly attached to the diaphragm member 114 and
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W09~/06728 "` `'''' ~7'' PCr/US91/07~99
~ o ~J
- which is substantially similar l;o the valve structure of the
previous embodiments. The regu,lator assembly includes a
first regulator portion having connecting memb~rs 118
extending radially inwardly toward a hub portion 120 from a
rim portion ha~ing a raised bead portion 126. The first
reglllator portion may be formed of the same material as the
diaphragm member 114 and is preferably formed integrally ' ''
with the diaphragm member 114. As in the previous
e~bodiments, the connecting members 118, rim portion and hub
portion 120 define a plurality of apertures in the first
regulator portion through which fluid m~y flow.
The hub portion 120 includes an extension 121
having an enlarged portion 122 for holding a second ~`'
regulator portion defined by a disk 124 in place on the hub
120 of the first regulator portion. As in the previous
embodiments, the disk 124 may be formed of a relatively
inflexible plastic and includes a lower surface which
contacts and forms a seal with the bead portion 126 of the
first regulator portion.
,~ 20 The housing 102 is further proYided with a seal
portion 128 which is located radially inwardly from the
'- flange 109 and which extends from the first housing half 110 ' ,
to-~ard the diaphragm member 114 for contacting and forming a
seal with the diaphragm member 114 along a contact 3urface
130. The seal portion 128 extends around the entire
circumference of and is located radially outwardly of the ;-
regulator assembly, and is located radially inwardly from
the convolution 116 of the diaphragm,member 114.
As may be seen in Fig. 5, the contact surfasce 130
positions the diaphragm member 114 in a common plane 131
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n~/o67~ t.~ J
~T/~91/07
-15-
with the flange portion 117. Further, the plane 131 passes
through the hub portion 120 of the regulator assembly below
the enlarged portion 122 at substantially the same location
as the point of intersection between the central axis 103
and the hub portion 120 below the enlarged portion 122.
It should also be noted that the seaI portion 128,
flange 109 and lip portion 111 define a chamber 119
extending around the periphery of the ho~lsing half 110, and
the convolution 116 extends up into the chamber-119 when the
contact surface 130 engages the diaphragm member 114.
In operatio~, a compressible air bag is attached
in fluid communication with the first opening 104 of the
valve housing 102 and the second opening 106 is placed in
fluid communication with a patient's respiratory system. As
the bag is compressed, air is forced from the first opening
104 toward the second opening 106 thus causing the disk 124
to move away from the bead portion 126 such that the air may
flow freely to the patient. During the operation of
; conveying the air from the bag to the patient, the diaphragm
member 114 remains in contact with the contact surface 130
of the seal portion 128 to thereby pre~-ent air from flowing
out of the housing 102 through the vent holes 108.
When pressure on the air bag is released, the
patient~exhales gases which force the disk 124 ~own onto the
bead portion 126 of the first regulator portion to thereby
prevent the exhaled gases from returning to the air bag.
Further, the exhaled ~ases also cause the diaphragm assembly
- 100 to move towa~d the first opening 104 such that the
diaphragm member 114 is moved out of sealing contact with
the seal portion 1~8, and the exhaled gases are discharged
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W~ 92/~6728 ~ r~ ~ PCT/US~)1/074!)9
~ .
-16-
out of the housing through the vent holes 108. It should be
apparent that the convolution 1;L6 facilitates the movement
of the diaphragm assembly 100 dtlring the passage of the
gases from the second opening 1()6 through the v~nt holes
108.
By incorporating the valve of the present
invention into an artificial respiration device, the
re~istance to air flow through the valve is minimized such
that the effort required to squeeze the air supply bag i~
drastically reduced, thus enabling the attending personnel
tn operate the bag for an extended period of time without
undue fatigue. In addition, the present valve provides an
advantage over prior art valve~ in that it does not produce
objectionable noises during operation. Further, the valve
of the pre~ent invention act3 as an effective barrier to
gases and fluids expelled by the patient wherehy ;-
contamination of the air supply bag is prevented.
While the forms of apparatus herein described
constitute preferred embodiments of the invention, it is to
be understood that the invention is not limited to these
precise forms of apparatus, and that changes may be made
therein w1thout departing from the scope of the invention
which is defined in the appended claims.
What is claimed i6:
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