Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~Z~65Z~ :
:` - .
--1-
~D~
This invention relate~ to apparatus for weighing collected
fluid during the collection process andt more particularly, to
means for isolating the weighing mechanism from coupling forces
of the fluid collection system and a method of uslng same to
obtain improved accuracy in weight measurements.
Varlous apparatus are known for determining the urinary
output of a patient which is med~u~ed in units of volume. In
U,S. Patent 4,448,207 of Parrish, the height of fluid in a
collection container is determined through ultrasonic echo
sensing, and then the volume is calculated by a computer based
upon a stored volumetric profile of the collection container
and the determined height. Similarly, in U.S. Patent 4,051~431 of
Wur ter, the level o a fluid in a container is determined by
means of capacitive sensing from which the volume can be
determined in a rigid container. In U.S. Patent 4,314,484 of
Bowman, an optical drop count apparatus first forms dcops from
the collected fluid of approximately a known uniform volume and
then counts the drops to determine the total volume accumulated.
A similar apparatus is also shown in U.S. Patent 4,291,692 of
Bowman~et al., U.S. Patent 4,347,316 of JesperSon and U.S.
Patent 4,286i590 of ~urase
Other techniques of measurement are also known. In U.S.
.
Patent 4,417,585 of Fran~k, moveable measurement containers are
alternately filled and dumped in a collection container, and the
volume is calculated by measuring the number of fill and dump
cycles. Similarly, in U.S. Patent 4,206,767 of Winegrovej a
plurality of measurement tubes are successively filled and sensed
to determine volume.
It has also been known to weigh the collected fluid and to
determine the volume froM-the weight. The weight and thus volume
is determinecl in U.S. Patent 3,583,400 of Menhardt by means foc
moving the collection fl~lid and determinlng the momentum of the
....
~.~." `
S2~
.~
- 2 - 71237-7
fluid from which the mass of collected fluid is calculated. In
an article by N. J. Randall, entitled "A New URO Flowmeter for
Routine Clinical Use" in the January, 1975, issue of Biomedical
Engineering (~ondon), a simple strain gauge transducer system
associated with a cantilever beam is employed to make direct
weight measurements. A special tube is provided to absorb and
redistribute urine flow into the container to prevent momentum
during flow from effecting the weight measurement.
It is also known to use the weight measurements of
collected fluid to control the fluid collection process itself.
For instance, in United States Patent 3,583,400 of Menhardt, a
switch controls fluid flow in a collection container in response
to measurement of collected fluid. Weight is used to stop a
blood co]lection proceqs when the amount collected exceeds a
preselected weight in an apparatus shown in United States Patent
3,977,567 of Rudd. In United States Patent 4,390,073 of Rosen,
blood in a collection bag is weighed to control collection.
~ hile other approaches for work, the measurement of
weight to determine volume is preferred. However, volumetric
measurements based on weighing the collected fluid chamber can be
no more accurate than the accuracy of the weight measurement
itself. Therefore, it is important to make sure that it is only
the weight of the fluid being measured and not the weight of the
container or the forces associated with the collection system
connected with the container which can affect the weight
measurment. One of the advantages that weighing has over other
methods of volume measurement is that the measurement does not
require a special rigid container for level sensing and can be
used after collection has commenced or after it is complete. In
known systems which measure volume, however, because of the
~2~S~I~
2a - 71237-7
accuracy problem caused by variable forces applied by the
upstream collection systems attached to the container, initial
amounts of fluid collected in a bag upon catherization and
before the bag is attached to the wei~hin~ apparatus are not
measured in order to zero the weighing apparatus. This is done
to partially offset some of the error introduced by the error
producing forces
21~
-- 3 --
applied by the force isolation system against the container.
SUMM~RY OF T~IE INVENTION
_ _
It is therefore the primary objec~ of the present in-
vention to provide apparatus with a forced isolation system
that overcomes the aforementioned problems with known weighing
: apparatus and a method of using same to measure all collected
: ~ fluid including the fluid collected before attachment of the
collected fluid container to the weighing apparatus.
According to one aspect of the present invention there
is provided apparatus for measuring the weight of fluid entering
a container of a system obtained from the downstream end of a
fluid drainage tube, comprising: a weighing apparatus having a
frame and a weighing mechanism which moves relative to the frame
during changes of the weight being weighed thereby; means for
connecting the container to the weighing mechanism to be weighed
thereby, said container moving with the weighing mechanism
relative to the frame as increasing amounts of fluid are intro-
: duced into the container; means for holding the downstream end
of the tube against movement relative to the frame; and means
for coupling the drainage tube with the container for relativefluid communication therewith including means for substantially
mechanically isolating the end of the tube from application of
significant force to the container whereby the accuracy of the
measurement of the weight of -the container and its contents is
not significantly affected by the coupling means.
According to another aspect of the invention there is
provided a container assembly for biological fluids, comprising:
a hollow container body having an inlet openlng for receipt of
fluids therewithin, an inlet connector for connection with the
end of a drainage tube, and means for substantially mechanically
i5Z~
-- 4
isolatiny the container body at the inlet opening from relative
movement of the inlet connector, said isolating means including
a flexible conduit for interconnecting the inlet connector and
the inlet opening, said conduit having a flexibility sufficient
to prevent it from mechanically conveying significant force in a
direction along the conduit.
According to a further aspect of the invention there
is provided a method of weighing a volume of fluid, comprising
the steps of: predetermining the weight of a fluid container;
offsetting the determined weight of the container from a weigh-
ing apparatus to zero the weighiny apparatus; connectiny the
downstream end of a drainage tube to an inlet opening of the
1uid container by means for substantially mechanically isolating
the container and the weiyhing apparatus from forces due to the
; interconnection of the container and the end of the tube; attach-
ing the container to the weighing apparatus to be weighed there-
by; enteriny the fluid to be weiyhed into the con-tainer through
the drainage tube and said isolation means; and weighing the
container and fluid therein.
~46~i~0
~ .. . . .. ... ~ . ~
~ ") ' .. )
--5--
; ~, ' .
: ''
'
:
L i~f De~ oe~ -eb~
. ~ .
The foregoing objects, featurea and advantage~ of the
present inventlon will be described ~n greater detail and further
objects and advantageous ~eatures will be made apparent in the
following detailed descrlption o the preferred embodiment which
is given with reference to the several figures of the drawing, in
which:
: Fig. lA is a perspective view of an automated urine output
monitor, or AUOM, for weighing and making other measurement~ of
urine collected in a flexible urinary collecti~n bag
:relea~ibly attached thereto and with respect to which a preferred
embodiment of the present invention is employed;
Fig. lB is another perspective view of the A~OM of Fig. lA
but wi~h the urinary collection bag and a front panel removed to
facilitate a better view of the inner workings of the A~OM;
Fig. 2 is a plan view of the AUOM of Fig~. lk and lB showing
the AUOM display and control panel;
Fig. 3 is an enlarged front view of a header assembly and
force isolatlon and sampling apparatus connected with the urinary
collection;
Fig. 4 is a plan view of the header assembly of Fig. 3
Fig, 5A is a sectional side view taken along section ~ine `
A of Fig. 3;
Fig. 5B is a sectional side view identical to that of Fig.
5A but with the header assembly in a relatively lowe~ position
due to increased wéight of the collected urine;
Fig. 6 is an enlarged perspective view of the force
isolation and sampling chamber assembly of ~igs. lA, 4, 5A and
5B;
Fig. 7 is a plan view of the header mounting mechanism of
~2~i5~
.
Figure lB;
Figures 8A and 8B a.re schematic illustrations of an
: alternate embodiment of the force isolation system of Figures 5A
and 5B under relatively unloaded and loaded conditions, respec-
tively;
Figures 9A and 9B are schematic illustrations of an-
;~ other alternate embodiment of the force isolation system under
relatively unloaded and loaded conditions, respectively;
: Figures 10A and 10B are schematic illustrations of ~
further alternate embodiment of the force isolation system underrelatively unloaded and loaded conditions, respectively;
Figures llA and llB are cross sectional and perspec-
tive illustrations of still another alternate embodiment of the
force isolation system; and
Figure 12, which appears on the same sheet as Figures
3 and 4, is a sectional side view of an alternate embodiment of
the force isolation system.
Detailed Description
Referring now to the several figures of the drawing,
. 20 particularly Figures lA, lB and 2, an automated urine output
monitor, or AUOM, 20 is seen with a flexible, plastic urinary
collection bag mounted thereto by means of a sampling chamber
assembly 24 and a force isolation system 26. As will be explain-
ed in greater detail, the sampling chamber assembly 24 and force
isolation system 26 interconnect to form a closed fluid collec-
tion system between a patient (not shown) connected to the distal
end of a Foley catheter 28 and the interior of the urinary
collection bag 22. The catheter 28 is connectable by means of a
catheter connector 29 and connector 31 with flexible, plastic
- 6a -
drainage tube 30. The other end of the drainage tube 30 is in
fluid communication with the sampling chamber assembly 24 by
means of a suitable tube connector located atop sampling cham-
ber assembly 24. Fluid from sampling chamber 24 flows through
a flexible conduit of the force isolation system 26 and through
an angular conduit 32 of a front entry connector assembly 34.
Referring to Figure lB, the AUOM is seen to have a
housing,
2a~
. ~. . . . . .
7-
comprised of a housing frame 36 with a removable front housing
panel 38. This housing protectively encloses an electronlc
control a~d measurement module 40 which includes a computer and
interface circuitry. The computer receive~ signals through ~he
interface circuitry from suitable transaucer~ associated with
sensor probe assemb}ie~ 42 and 44 connectlble with the sampling
chamber a~embly 24 for noninvasively determining both speclf~c
gravity and temperature of a urine sample contained within the
chamber assembly 24. The computer is also responsive to
electronic signals received through other interface circuitry
from transducers associated with a pair of mountlng arms 46 and
48 of a bag mounting assembly S0 to determine the weight of the
urlne collected within urinary collection bag 22. The computer
also determines core temperature based on signals from a
temperature tran~ducer associated with a core temperature probe
within catheter 28 and connected thereto by means of an
electrical cord 52. The computsr also receives signals through
suitable transducers indicative of the ambient temperature, the
status of it~ D.C. portable battery supply (not shown) and
signals fro~ a control section 54 of a control and display panel
56, Fig. 2. These controls include a manually actuatable reset
switch 58, a start switch 60, a temperature scale selection
switch 62 and a display light actuation switch 64.
Referring to Fig. 2, the computer automatically,
periodically calculates specific gravity, temperature, volume and
time based upon these transducers and control input signals and
causes them to be visually indicated at various electronic
digital display units of a display section 66 of control and
display panel 56. The volume in milliliters of the urine
collected in ba~ 22 for the present hour, the previous hour and
for all collection accumulated is indicated at display units 68,
70 and 72. Based upon appropriate signals received from either
the start switch 60 or reset switch 58, and an internal clock,~
~he computer also indicates the number of minutes elapsed since
the present hour commenced and the cumulative time since the
collection process started at display units 74 ancl 76,
~24~S;2f~
- 8 - 71237-7
respectively. The specific gravity is shown in display unit 78,
and core temperature, either in Fahrenheit or centigrade degrees
depending upon the state of scale selection switch 62, is shown
at display unit 80. A low battery condition for the portable
AUOM is provided by an indicator 82, and various conditions
sensed by the computer are indicated by an alpha numeric message
display unit 84 and an alert indicator lamp 86.
In normal operations, the AUOM unit is releasably
attached to an upright mounting standard 90 by means of a
screw clamp 92 attached to the back of housing 22.
The catheter set, consisting of catheter 28, catheter
drainage tube 30, sampling chamber assembly 24, force isolation
system 26, Eront entry connector assembly 3~ and collection
bag 22 are brought to the patient and the patient is catherized.
; After the AUOM unit has been mounted in a correct location for
the patient and after the catherization procedure, the urinary
collection bag 22 is taken to the AUOM unit 20 which is
located outside of the sterile field of the catherization site
and is mounted to the AUOM unit. ~he force isolation system
26 includes a relatively rigid header assembly 94 having a pair
of spaced
`~ 12~6S20
`: . ... ~ ~ . . .
~.
.
~. ~. ... .. ..
~ ) g
female connectorB 96 and 98 which are adapted for mating receipt
of moun~ing a~ms 46 and 4a, respectively, to suspend the
collection bag 22 therefrom. As will be explained in ~reater
detail below with reference to Fig. 7, means ar~ provided for
caùsing arms 46 and 48 to in~erloc~ with female connectors 96 and
98.
After a pair o protective ~ensor caps 102, only one of
which i8 shown in Fig~ 3, are removed from a pair of probe guide
connectors 104 and 106~ the probe quide connectors 1~4 and 106
are enabled for mating receipt o~ ~ensor probe assemblies 42 and
44, re~pectively. Once caps 10~ are removed, the sa~pling
chamber as~embly 24 i~ enabled for receipt within a sensing
locatlon 108 with sensor probe guide connectors 104 and 106
located respectively opposite sensor probe~ 42 and 440 The
collection bag 22 i5 then locked onto arm~ 46 and 48.
The two sensor probe as~emblies 42 and 44 are then caused to
move together through manual actuation of a probe actuator 110.
When the actuator 110 is movqd from its position as shown in Fig.
lB to the operative position shown in Fig. lA, the two sensor
probes move together and respectively matingly engage the sensor
probe guide connectors 104 and 106. Since the drainage tube 30
is mounted to sampling chamber assembly 24, both it and the
downstream end of the drainage tube 30 are held~against any
movement relative to the housing frame 36. After this is done,
the start switch 60 is actuated and the AUOM unit 20 begins
operations to provide the monitor information described above~
The details of the force isolation system 26 and the
sampling chamb~r assembly 24 are described with reference to
Figs, 3, 4, 5A, 5B, 6 and 7.
Referring particularly to Figs. 3 and 4, the header assembly
94 is seen to comprise a central body 111 with a central force
isolation header connector 112 located between the pair of female
connectors 96 and 98 together with a pair of opposed header.
mounting arms 114 and 116. The header is secured to the flexible
bag 22 by means of a pair o header mounting pockets 118 and 120
within which are held mounting arms 114 and 116, respectively.
12~S~
.
.
. .
:~ -` . ;
--1 o--
These poc~ets are formed from extensions of the back and front
walls 130 and 128 o ur~nary collection bag 22 Wh~ch are secured
together along a common seam 122 and a pair of upp~r seams 124
and 126 respectively as~ociated with header mounti~g pockets 118
and 120. During manufacture, the header assembly 94 is placed in
position with it~ header mounting arms 114 and 116 between the
front and back walls of collection bag 22 prior t~ the formation
o seam~ 124 and 126. Alternately, if sufficient clearance is
provided or the relatively rigid header assembly arms 114 and 116
are su~ficiently flexible, the arms 114 and 116 aee inserted into
pocket~.ll8 and 120 after all the seams are formed.
Referrlng also to Figs~ 5A and 5B, a front wall 128,
~pposite a back wall 130 of urinary collection bag 22, is seen to
ha~ve an inlet opening 132 in fluid communication with a coupler
134. Coupler 134 is sealed to the front wall 128 of flexible bag
22, by means of a flexible peripheral mounting collar 135 which
is sealed to the front wall 128 around the periphery of inlet
132. A fluid conductive connector a~sembly, which forms part of
the force isolation system 26, includes a dow~turned, elongate
portion, or angular conduitl 138 for making fluid connection with
the front 128 of the flexible bag 22 through coupler 134 and
inlet 132. This angular conduit 138 is in fluid communication
with a hopper por~ ion 140 of rela.tivaly larger diameter, a
shoulder 142, a flexible diaphragm mounting portion 144 and a
movement restraint portion 146.
As seen, the angular conduit 138 e~tends at an acute angle
relative to the back wall 130 of:-the collection bag 122. This
enables it to ma~e connection with the coupler 134 at a location
offset from the central vertical plane of symmetry of the bag.
This is the location that the portion adjacent coupler 134 of the
walI 128 would move to as the bag 22 became full i there were
not restraint on it~ movement. Otherwise during filling
asymmetrical backward bulging of the collection bag 22 would;
result because of wall 128 being held at the vertical plane by
the conduit 138
Thi~ bulging would undesirably require more clearance
- ~2~iS~
..
between the A~OM housing panel 38 and the collec~ion bag 22.
The coupler 134 has a coupler axis 148 which extend~ in a
directlon sub~ta~tially parallel to the front of the bag a~ the
peripheral collar 135. A fir~t member 150 hax an axis 1$2 which
extend~ at a right angle relative to the front of the bag at
mounting collar 135~ The connector portion 154 associated with
axis 148, on the other handr extends in a direction ~ub~tantially
transverse to that of the fir~t portion 150 to form a right angle
connection. As best seen in Fig. 5B, the axis 148 also forms an
obtuse angl~ with the central axis of hopper portion 140 and
connector 112.
During assembly, the angular conduit 138 and hopper portion
140 are received through the central force isolation connector
112~ The header connector 112 is a cylindrical female
connector for mating receipt of ~he.cylindrical wall of the
hopper portion 140. In order to prevent rela.tive rotary
movement, howe~er, the cylindrical wall of header connector 112
has an interlock notch 156, as best seen in Fig. 4, which is
adapted for mating receipt of a mating interlock member 158 seen
in Figs. SA and 5B. The mating interlock member 158 is carried
on the side wall of hopper portion 140 and is snugly received
therein to prevent relative rotary movement between the hopper
portion 140 and the central force isolation connector of header
assembly 94. In addition, ~ince only a single asymmetrically
located interlock notch 156 and interlock member 158 are
provided, the hopper po~tion 140 and the central force isolation
header connector 112 are thereby keyed to require theie
intercoupling in a preselected orientation relative to the inlet
132.
After full insertion, the coupler 134 is pivoted
upwardly ~or mating receipt of the open end o~ the angular
conduit 138. After this connection is made, the interconnections
between the connector 112 and hopper portion 140, connector 112
and shoulder 142 and connector portion 154 and the distal end of
angular conduit 138, are rendered permanent by the application o~
adhesive, by setting of previously applied adheslve or by heat
~24~
.
.
,~
-12-
fuslon or solvent bond.
Thu~, the fluid conductive connector assembly 32 i5
permanently and fixedly attached to the urinary collection bag
22. It thereby form3 a first rela~ively rigid connector ~or
connecting one end of a highly flexible diaphragm, or condui~,
164 to form part of the force isolation system 26. As will be
explaine~, the other part of the forc~ ~solation sy tem comprises
means for holding and interconnecting a down9tream open end 166
of drainage tube 30 to the other end o flexible diaphragm 164
and for holding the drainage tube end 166 flxed relative to the
housing frame 36.
In the instant case of the preferred embodimentt the
relatively rigid connector for connecting the distal end 166 to
~the end 168 of the flexible diaphragm 164 includes a sampling
chamber as~embly 24 and means associated therewith. However, it
should be appreciated that the sampling chamber function is not
necessary to achieve force isolation and in the absence of such a
chamber, a simpler connector may be employed for connection of
the drainage tube downstream open end 166 to the upstream end of
the flexible diaphragm.
Since the end 166 of drainage tube 30 is held firmly, the
collection ~ag ~s isolated from force applied thereto. The high
degree of flexibilit~ of the diaphragm 164 prevents the
connection thereof with the collection bag 22 from applying any
significant restraint or other force thereto or to the welghing
apparatus to which it i~ attached. Briefly, sampling chamber
assembly 24, as seenf has a sampling çhamber 17~ contained within
a sampling chamber housing 172 intermediate a housing inlet 174
and an outlet 176~ The inlet 174 is connected in fluid
communication with the open end 166 of drainage tube 30 by means
of an annular inlet connector 178. After the flexible drainage
tube 30 is inser~ed into mating relationship wi~h connector 178,
the connection is rendered permanent by means Oe applying
adhesive, causing preapplied adhesive to set, by solvent bond or
the like. Urine dripping out of the inlet 174 falls into a
combined inlet and outlet opening 180 of sampling chamber 170.
5;2~
- ' ~ -.
- ,
-13-
After th~ sampling chamber 180 is filled, additional urine
fallin~ into the open top 180 will both mix with the prev~ously
collected urine i~ the sampling chamber and will cau~e other
urine ~o overflow and fall through the ou~let 176 and into hopper
portion 140 of connector 136.
The outlet 176 is connected through an elongate conduit 182
interconnected at its distal end wlth a diaphrag~ co~nector 184.
The flexible diaphragm 164 comprises a thin, flexlble moisture
impervious material, such as thin rubber, animal membrane, or the
like, which forms part of a closed fluid collection system
between the end 166 of drainage tube 30 and the aollection bag
22. It has a relatively large ~nlet opening at the ends of a
mounting collar 186 which is re~iliently secured around the
annular diaphragm mounting portion }44 of the connection assembly
32. ~t it~ other end, it has another annular collar 188,
opening~in a direction opposite to that of collar 185 and having
a relatively smaller diameter to re~iliently fit around the end
of a diaphragm connector 184. A concave flexible wall
interconnects collars 186 and 188.
The force isolation system 26 operates as follows. When the
collection bag 22 is mounted to the header assembly 94f it is
fixed}y held to arms 46 and 48 which, in tur~, are connected with
a weight tr~nsducer which responds to the total force imposed
upon arms 46 and 48~ Ideal.ly, this total force corresponds only
to the weight of the fluid contained in the urinary collection
bag 22 and the weight of the collection bag 22 itself which is
known and can be offset to precisely calculate the weight of the
urine alone. However, the urinary collection bag 22 must be
connectéd to the end 166 of the drainage tube for receipt of the
uri~e, and in the absence of a force isola~ion system, forces are
imposed through the drainaqe tube 3~ which a~e t~ansmitted to
arms 46 and 48 and thereby introduce error into the weight
calculation.
The arms 46 and 4~ are caused to move downwarclly by the
weight of the urine being collectedr but the end 16~ of drainage
tube 30 is held stationary relative to the housing frame 36 of
- ~L2~ 0
,
14-
the AUO~ unit 20 by means of the mating insertion of sen~or probe
guides 42 and 44 within guide con~ectors 104 and 106 Thus,
forces applied to the end 166 of ~he drainage tube 30 are borne
by the AUOM unit 20 and they are not transmitted ~o the header
assQmbly 94. The flexible diaphragm 164 is then the only element
which can ~ransmit extraneous forces through the weighing
mechanism. However, the flexible diaphragm is purpo9ely selected
to be so fl~xible that i~ is not capable of sustaining or
supportlng any significant force~ either in a dlrection along its
principal axi9 of movement coincident with the elongate axis of
conduit 182. It can be maintained in a relatively stable state
in any of several relative positions without transmitting any
significant force along its length. Accordingly, the mounting
arms 46 and 48 and collectlon bag 22 are free to move~relative to
the frame 36 in substantial isolation from any forces from the
urinary delivery sys~em from the patient to the collection bag
~2.
Referring particularly to Figs. SA and 5B, when the
collection bag 22 is first attached, the relative location of the
mounting arms 46 and 48 relative to the sampling chamber assembly
is as shown in Fig. 5A. As seen, the underside surface 192 of
sampling chamber housing 172 rests atop restraint portion 146 of
connection assembly 32. However, after the sensor probe
~assemblies 42 and 44 are engaged with the sampling chamber
assembly 24, the underside surface 192 is held the~eby slightly
above restrain~ portion 146. However, as urine is added to the
collection bag 22 and its weight increases, the mounting arms 46
and 48 and thus connector assembly 136 attached thereto, move
downwardly away from an underside surface 192 o~ sampling chamber
housing 172, causing the inlet opening at diaphragm collar 186 to
move clo~er to the outlet opening at diaphragm collar 188. This
relative movement is not signi~icantly resisted by the concave
wall 190 which forms a downwardly facing cuff within the space
l9S between shoulder 142 and restraint portion 146, as shown in
Fig. 5B, in response to this relative movement.~ This cuff moves
along the length of the concave wall 190 of flexible diaphragm
- .
': . :` . ` -
- `) ` ..
164 as the connectors 144 and lB4 are moved relative to one
another.
eferring still to Fig3. 5A and 5B, particularly Fig. SA,
~he diaphragm c~nnector 184 carrie~ a stop member 194 which $s
engayeable ~n block~ng relat~onship with the underside 196 o
~estraint po tion 146 to re~train relative moYement between the
inlet and outlet connectors of the flexible diaphragm 164 beyond
a pre~elected limit. Movement beyond this limit would cause the
transmis~ion of force to the header assembly 94 through means of
the connector a~sembly 136 or which would qtretch or otherwise
damage the ~lexible cliaphragm 164.
As ~est seen in ~lg. 6, the force isolation system 26 also
include3 means for restralning relative rotary movement between
the ends of the fléxible diaphragm which would twist it beyond a
preselected limit. The rotary restraint is provided by means o~
a pair of radial blocking members l9B and 200 fixedly attached to
the elongate conduit 182 of sampling chamber assembly 24 and
received within a pair of slots 202 and 204. Slots 202 and 204
are formed by a pair of opposed arcuate sections 206 and 208 of
restraint portion 146. Each of arcuate sections 206 and 208
define a pair of rotary blocking surfaces 210 and ~12 at opposite
sides of slots 204 and 202 which are spaced from one another by a
preselected amount corresponding to the preselected limit. The
blocking surfaces prevent the radial blocking members 198 and 200
associated therewith and thus the flexible diaphragm 164 from
rotary movement beyond the preselected limit.
Referring now to Fig. 7, the detailed features of mating
relationship between the female connectors 96 and 98 of header
assembly 94 with the mounting arms 46 and 48 and other features
of the bag mounting assembly 50 will be describecl. Each of the
arms 46 and 48 are mirror images of one another ancl have a
manually engageable portion 220 which extend through the
a~sociated female connector 96 and g8 or access at the front of
the eollection bag 2~. ~oth of arms 46 and 48 are made of
relatively resilient material and the distance d between a pair
of outwardly facing planar cam surfaces 238 and 240 of arms 46
.
- ~ lZ4~520 : -
.
.
-16-
and 48, when in a neu~ral~ or unflexed, condition, is greater
than the distance D between a pair of inwardly facing interlock
sur~aces 22S and 228 of femal~ connectors 96 and 98,
respectively. A pair:of shoulders 242 and 244 are formed at the
edge of each of the outwardly facing planar cam surface~ 238 and
240 and a pair of interlock surfaces 222 and 224 of arms 46 and
48, respectively, which mating~y receive the associated
interlocking surfaces 226 and 228. When female connectors 96 and
98 are slid over the manually accessible portions 220 of arms 46
and 48, arcuate caming surfaces 234 and ~36 carried thereby
respectively engage interlock surface~ 222 and 224 and are
thereby gradually, resiliently cammed ~ogether until the distance
between outwardly facing planar cam surfaces 238 and 240 is equal
to the distance D. The planar cam surfaces 238 and 240 then ride.
the interlock surfaces 226 and 228, respectively. When the
lagging edges of interlock surfaces 226 and 228 pass shoulders
242 and 244, the arms 46 and 48 resiliently snap apart with the
mating interlock surfaces joined as shown. The shoulders 242 and
: 244 then abut against the edge of their associated female
: :connector interlock surfaces to prevent removal of the connectors
from the arm. Thus, to mount the header asse.mbly to arms 46 and
48, the female connectors only need to be slid on to their
: : associated arms to automatically move them to an interlock
position from their release position until the arms resiliently
snap into the interlock posi~ion~ as shown in Fig. 7. Once this
occurs, a pusher member 248 resiliently pushes shoulders 243 and
245 of the female connectors against shoulders 242 and 244 o~ the
arms.
The female connectors are automatically- disengaged from the
arms 46 and 48 when the manually engageable portions 220 of arms
46 and 48 are squeezed together sufficiently to move shoulders
242 and 244 out of blocking engagement. These shoulders, or
blocking edges, 242 and 244 resist resilient biasing of the
header assembly and female connectors thereagainst provided by a
coil sprlng 246 associated with a pusher member 248 mounted
within a cylindrical housing 250. This pusher member causes the
~ lZ4~520
! -17- ~
female connectors 96 and 98 to automatically, slideably move off
of interlocking engagement with armR 46 and 48 when the distance
between cam surfaces 238 and 240 i~ less than the dis~ance D
between the interlock surfaces 226 and 228 of the connector
Thus, .the connectors are automatically disengaged from arm~ 46
and 48 simply by manually squeezing the manually accessible
portion~ 220 togeth~r from the interlock posltion to the ~elease
position.
Referring to Figs. 8A through l}B, alternate embodiments of
the flexible diaphragm and associated connec~ors of the ~orce
isolation systems are schematically illustrated. In Figs. 8A and
8~, a ~lexible diaphragm 252 is shown with an inlet 254 and
outlet 25~ of approximately the same diameter and which has
substantially straight walls rather than concave walls, as in the
preferred embodiment of Fig~. 4, 5A and 5s. An inlet connector
258 is held to the frame and connected to the drainage tube 166
and an outlet connector 260 is connected to the collection bag 22
~not shown). In addition, as best seen in Fig. 8A, 258 and 260
when the collection bag is relatively empty, the flexible
diaphragm 252 forms a cuff 262 which ~aces upwardly toward the
inlet connector 258. A~ the collection bag 22 fills, the outlet
connector 260 mo~es downwardly closer to the inlet connector 258,
as shown in Fig. 8B.
Referring to Fig. 9A and ~B, another embodiment of a
flexible diaphragm 264 is shown under circumstances of a relatively
empty and relatively full urinary collection bag 22,
respec~ively~ In this embodiment, the flexible diaphragm 264 has
an upturned mounting cuff 266 which matingly receives an annular
outlet connector 268 and the inlet end of flexible diaphragm 264 has
a collar 270 connected to an inlet connector 272 o~ lesser
diameter than outlet connector 268. A downwardly turned cuff 274
is formed in flexible diaphragm 264 which is gradually removed as
the connectors 272 and 268 separate as shown in Fig. 9B until, at
ull extension, the ~lexible diaphragm 264 has a conical shape,
as shown in Fig. 9B. Unlike the embodiments of Figs. 8A and- 8B~
and ~igs. SA and SB, the inlet is located above the outlet in the
~2~6S~ :
.
.
.
embodiment of ~igs. 9A and 9B.
Rcferring now to Figs. lOA and lOB, another embodiment of a
flexible diaphragm 27G is shown in which an inlet end is con~ected
to an inlet connector 278 by means of a collar 280, and the outlet
end ha~ a collar 282 which is held between a pair of outlet
connector members 284. An upturned cuff 286 faces the inlet
connector 273, and when the flexible diaphragm 276 is extended, as
shown in Fiq. lOB, the cuff 286 moves upwardly until a conical
configuration is obtained, as shown.
Referring now to Figs. llA and llB, yet another embodiment
of-a ~lexible diaphragm 288 is shown similar to that of Figs. lOA
and lOB but in which the body of the flexible diaphragm is bell
Rhaped when extended, as shown in Fig. 118, and which has a
laterally ex~ending collar 290 attached to a laterally extending
outlet connector 292 instead of the vertically extending collar
and outlet connector of Fig. lOA. Like Fig. lOA, an upturned
cuff 294 i~ formed when the irilet connector 292 and an outlét
connector 296 are spaced from one another as shown in Fig. llA.
Reerring to Fig. 12, a schematic illustration of yet
another embodiment o the force isolation system 26 is shown in
which the flexible diaphragm 298 is generally cylindrica} and
does no~ form either an upturned or a downturned cuff, but merely
folds in a random or accordian fashion, as shown. The outlet
connector 3bo directly attaches the outlet of the flexible
diaphragm 298 to an inlet 302 of the flexible bag 22 located at
the top 3a4 of the bag 22 rather than at its front wall 128. An
inlet connector 306 is directly connected to the end 166 of the
drainage tube 30. Relative lateral movement of the first and
second connectors beyond a preselected limit is prevented by
means including blocking arms 308, and relative rotary movement
beyond a preselected limit is restrained by means including a
pair of restraint members 310 which cooperate with radial vanes
312.
Advantageously, because of the improvement of
accuracy obtained as a result of the force isolati~n system,-an~
;mproved method of weighing urine collected from a patient is
~2`4~i~i2~ -`-`- ~
--19--
provided. In prior weighing systems, becaus~e of the unknown
magnitude of extraneou forces applied to the collection bag and
weighinq apparatus by the urine delivery system, urine entered
into the collection ~ag upon c~therization and before mounting of
the collection bag to the weighing appara~us, was not accurately
weighed. It is not accurately weighed in prior devices because of
the need of first zeroing the we~ghing apparatus to insure the
degree of accuracy needed ~or flow rate and other measurements.
Of~setting the determined weight before attachment of the bag to
zero the weighing apparatus for empty bag weight is preferred.
However, in the method provided here, the step of zeroing after
mountlng the collection bag is eliminated, so that the urine
collected prior to mounting may be accurately weighed and volume
determined
In particular, a method for weighing a volume of fluid is
provided comprising the steps of (a) predetermining the weight of ~.
the urine collection ba~ 22 based on an average bag weight of a
large sample of substantially identical bags, (b) offsetting the
determinant weight of the bag 22 from the weighing apparatus of
the AUOM unit 20, ~c) connecting the downstream end 166 o~ the
drainage tube 30 to an inlet 132 of bag 22 by means including the
force isolation system 26 to substantially mechanically isolate
the bag 22 and the weighing apparatus to which it is connected
from forces due to the interconnection of the bag 27 and the end
166 of tube 30, ~d) attaching the ba~ 22 to the bag mounting
assembly 50 to be weighed, and ~e~ entering the urine to be
weighed into the bag 22 through tube 30 and the force isolation
system 26.
Thus, the urine which may enter the collection bag 22 before
the bag 22 is attached to the bag mounting assembly 50 is
we~ghed because the weighing apparatus is not zeroed to cancel
out the weight of thi~ previously collected urine. Accordingly,
the AUOM unit weighs it together with the urine subsequently
collected to give a combined weight or volume indicatlon.
While a particular embodiment has been shown, it should- be `
appreciated that variations may be made with regard thereto
` . :
~ - : lZ465?q3:
-20-
without departing from the scope of the invention. For instance~
although a flexible pla~tic bag 22 has been disclosed for
collecting urine, it should be clear that many of the
advantageous features of the invention could be successfully
employed with rigid fluid containers or container and collection
3ystem~ for other types of biological fluids, such a~ blood.
Thus, the scope of the invention is defined by the following
~laims and not by the foregoing detailed description of the
preferred embodimen~.
