Connection apparatus for side connection to fluid collection bag

A front entry, flexible urinary collection bag with an inlet opening at a front wall thereof is connected with a fluid source through a rigid header attached to the flexible bag adjacent the inlet opening at the front of the bag and a fluid conductive connector held in coupling engagement by the header and having an elongate portion which makes fluid connection with the front of the bag through the inlet opening. The portion extends at an acute angle relative to the back of the bag when empty and makes connection with the front of the bag at a location laterally offset from the plane of symmetry, so that the back wall will not asymmetrically bulge away from the central plane of symmetry relative to the front of the bag. A front entry urinary collection bag adapted for automated urinary output monitoring is made by attaching a relatively rigid header to the top of the bag, attaching the inlet coupler to the front of the bag adjacent the top, inserting a male fluid conductive connector into mating relationship with a female connector carried by the header at the top of the bag and coupling a downwardly extending portion of the male connector to the inlet coupler.

BACKGROUND OF THE INVENTION 
This invention relates to apparatus for making connection between a fluid 
source, such as a catheter, and a flexible collection bag, and a method of 
making a urinary collection bag incorporating such apparatus. 
A difficulty in making fluid connection with the front of a flexible bag, 
such as a urinary collection bag, through means of a relatively rigid 
connector is that as the bag fills with fluid, it tends to expand. In a 
symmetrical bag with a relatively rigid header at the top of the bag at a 
center plane of symmetry between a front and back wall of the bag, the bag 
expands symmetrically relative to this center plane in the absence of any 
interference. In such case, the front and back walls bow out away from one 
another and the center plane of symmetry as the bag fills. 
However, if a rigid connector is attached to the front of the bag at the 
plane of symmetry when the bag is empty and the walls collapsed adjacent 
the center plane, the front wall will be restrained against lateral 
movement away from the plane of symmetry. Accordingly, as such a bag fills 
with fluid, the back wall will bulge asymmetrically away from the center 
plane of symmetry and away from the front wall. If the bag is suspended 
from a weighing apparatus of an automated urinary output monitor, or the 
like, such asymmetrical bulging could result in the bag brushing against 
the frame or other parts of the monitor unless additional clearance for 
such bulging is provided. Touching of the bag against any part of the 
monitor would introduce unacceptable error to the weight measurement. 
Adding additional clearance, on the other hand, requires a greater overall 
dimension for the monitor. 
While such a problem can be avoided by making connection at the top of the 
bag, such a top connection may unacceptably result in a greater overall 
length for the bag and connector combination. 
Accordingly, a need exists for apparatus for making connection of a fluid 
source to the front of a flexible bag but which will not result in such 
undesirable asymmetrical bulging. Likewise, a need exists for a method of 
making a front entry urinary collection bag which overcomes this defect in 
known collection bags. 
SUMMARY OF THE INVENTION 
It is therefore the principal object of the present invention to provide an 
apparatus for making connection between the front of a flexible bag and a 
fluid source and a method for making such a urinary collection bag that 
does not asymmetrically bulge as the bag is filled. 
The first part of this objective is achieved through provision of an 
apparatus for connection of a fluid source to a flexible bag having front 
and back walls on opposite sides of a plane of symmetry of the bag, 
comprising, a relatively rigid header attached to a flexible bag adjacent 
an inlet opening at the front of the bag and a fluid conductive connector 
held in coupling engagement by the header and having an elongate portion 
for making fluid connection with the front of the flexible bag through the 
inlet opening thereof. This portion extends at an acute angle relative to 
the back of the bag when empty and makes connection with the front of the 
bag at a location laterally offset from the plane of symmetry. 
In a preferred embodiment, the header also includes means for suspending 
the bag from a support and in which the connector has a portion which 
functions as part of a force isolation system for the flexible bag. 
The second part of this object is achieved through provision of a method of 
making a front entry urinary collection bag adapted for automated urinary 
output monitoring comprising the steps of fixedly attaching a relatively 
rigid header to the top of the bag, fixedly attaching an inlet coupler to 
the front of the bag adjacent the top of the bag, inserting a male fluid 
conductive connector into mating relationship with a female connector 
carried by the header at the top of the bag and coupling a downwardly 
extending portion of the male connector to the inlet coupler. Preferably, 
after the connections are made, the connection between the inlet connector 
and the downwardly extending portion is rendered permanent and after this 
connection is made permanent, the bag is sterilized. In a preferred 
embodiment, a catheter drainage tube is also connected to the male 
connector to form a closed urinary collection system.

DETAILED DESCRIPTION 
Referring now to the several figures of the drawing, particularly FIGS. 1A, 
1B 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 
explained in greater detail, the sampling chamber assembly 24 and force 
isolation system 26 interconnect to form a closed fluid collection 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 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 
chamber 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 FIG. 1B, the AUOM is seen to have a housing, comprised of a 
housing frame 36 with a removable front housing panel 38. This housing 
protectively encloses an electronic control and measurement module 40 
which includes a computer and interface circuitry. The computer receives 
signals through the interface circuitry from suitable transducers 
associated with sensor probe assemblies 42 and 44 connectible with the 
sampling chamber assembly 24 for noninvasively determining both specific 
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 mounting arms 46 and 48 of a bag mounting assembly 50 to 
determine the weight of the urine collected within urinary collection bag 
22. The computer also determines core temperature based on signals from a 
temperature transducer associated with a core temperature probe within 
catheter 28 and connected thereto by means of an electrical cord 52. The 
computer also receives signals through suitable transducers indicative of 
the ambient temperature, the status of its D.C. portable battery supply 
(not shown) and signals from 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 bag 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, the 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 and 76, 
respectively. The specific gravity is shown on 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. 
Further information concerning the operation of the computer, transducers 
and other aspects of the AUOM unit 20 may be obtained by reference to the 
U.S. patent application No. 684,235 of Brian H. Silver entitled 
"Electronic Biological Fluid Output Monitoring With Noninvasive Sensing", 
U.S. patent application Ser. No. 683,980 of Frank W. Ingle and Alan R. 
Selfridge entitled "Biological Fluid Specific Gravity Monitor with 
Ultrasonic Sensor Circuit", and U.S. patent application Ser. No. 683,981 
of Fred Rasmussen entitled "Ultrasonic Sensor", all filed 
contemporaneously herewith and assigned to the assignee of this 
application. 
In normal operations, the AUOM unit is releasibly attached to an upright 
mounting standard 90 by means of a screw clamp 92 attached to the back of 
housing 22. Although standard 90 may be mounted to its own floor supported 
base member 93, as shown, preferably standard 90 is releasibly mounted to 
the patient's bed in a manner shown in U.S. patent application No. 
06/684,238 filed Dec. 20, 1984, of James R. Gross, entitled "Medical 
Equipment Mounting Apparatus" filed contemporaneously herewith and 
assigned to the assignee of this application. 
The catheter set, consisting of catheter 28, catheter drainage tube 30, 
sampling chamber assembly 24, force isolation system 26, front entry 
connector assembly 34 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. The force isolation system 26 includes a 
relatively rigid header assembly 94 having a pair of spaced female 
connectors 96 and 98 which are adapted for mating receipt of mounting arms 
46 and 48, respectively, to suspend the collection bag 22 therefrom. As 
will be explained in greater detail below with reference to FIG. 7, means 
are provided for causing arms 46 and 48 to interlock with female 
connectors 96 and 98. 
After a pair of protective sensor caps 102, only one of which is shown in 
FIG. 3, are removed from a pair of probe guide connectors 104 and 106, the 
probe quide connectors 104 and 106 are enabled for mating receipt of 
sensor probe assemblies 42 and 44, respectively. Once caps 102 are 
removed, the sampling chamber assembly 24 is enabled for receipt within a 
sensing location 108 with sensor probe guide connectors 104 and 106 
located respectively opposite sensor probes 42 and 44. The collection bag 
22 is then locked onto arms 46 and 48. 
The two sensor probe assemblies 42 and 44 are then caused to move together 
through manual actuation of a probe actuator 110. When the actuator 110 is 
moved from its position as shown in FIG. 1B to the operative position 
shown in FIG. 1A, 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 chamber 
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 of header 
mounting pockets 118 and 120 within which are held mounting arms 114 and 
116, respectively. These pockets are formed from extensions of the back 
and front walls 130 and 128 of urinary collection bag 22 which are secured 
together along a common seam 122 and a pair of upper seams 124 and 126 
respectively associated with header mounting pockets 118 and 120. During 
manufacture, the header assembly 94 is placed in position with its header 
mounting arms 114 and 116 between the front and back walls of collection 
bag 22 prior to the formation of seams 124 and 126. Alternately, if 
sufficient clearance is provided or the relatively rigid header assembly 
arms 114 and 116 are sufficiently flexible, the arms 114 and 116 are 
inserted into pockets 118 and 120 after all the seams are formed. 
Referring also to FIGS. 5A and 5B, a front wall 128, opposite a back wall 
130 of urinary collection bag 22, is seen to have 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 assembly, which forms part of the 
force isolation system 26, includes a downturned, elongate portion, or 
angular conduit, 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 portion 140 of relatively 
larger diameter, a shoulder 142, a flexible diaphragm mounting portion 144 
and a movement restraint portion 146. 
As seen, the angular conduit 138 extends at an acute angle relative to the 
back wall 130 of the collection bag 122. This enables it to make 
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 wall 128 would move to as the bag 22 
became full if there were not restraint on its 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. 
This bulging would undesirably require more clearance between the AUOM 
housing panel 38 and the collection bag 22. The coupler 134 has a coupler 
axis 148 which extends in a direction substantially parallel to the front 
of the bag at the peripheral collar 135. A first member 150 has an axis 
152 which extends 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 hand, extends in a direction substantially transverse to that 
of the first portion 150 to form a right angle connection. As best seen in 
FIG. 5B, the axis 148 also forms an obtuse angle 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 the 
cylindrical wall of the hopper portion 140. In order to prevent relative 
rotary movement, however, 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. 5A 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, since only a single 
asymmetrically located interlock notch 156 and interlock member 158 are 
provided, the hopper portion 140 and the central force isolation header 
connector 112 are thereby keyed to require their intercoupling in a 
preselected orientation relative to the inlet 132. 
After full insertion, the coupler 134 is pivoted upwardly for mating 
receipt of the open end of 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 of adhesive, by setting of previously applied adhesive or by 
heat fusion or solvent bond. 
Thus, the fluid conductive connector assembly 32 is permanently and fixedly 
attached to the urinary collection bag 22. It thereby forms a first 
relatively rigid connector for connecting one end of a highly flexible 
diaphragm, or conduit, 164 to form part of the force isolation system 26. 
As will be explained, the other part of the force isolation system 
comprises means for holding and interconnecting a downstream open end 166 
of drainage tube 30 to the other end of flexible diaphragm 164 and for 
holding the drainage tube end 166 fixed relative to the housing frame 36. 
In the instant case of the preferred embodiment, the relatively rigid 
connector for connecting the distal end 166 to the end 168 of the flexible 
diaphragm 164 includes a sampling chamber assembly 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 bag is 
isolated from force applied thereto. The high degree of flexibility 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 
weighing apparatus to which it is attached. Briefly, sampling chamber 
assembly 24, as seen, has a sampling chamber 170 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 inserted into mating 
relationship with connector 178, the connection is rendered permanent by 
means of 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. After the 
sampling chamber 180 is filled, additional urine falling into the open top 
180 will both mix with the previously collected urine in the sampling 
chamber and will cause other urine to overflow and fall through the outlet 
176 and into hopper portion 140 of connector 136. 
The outlet 176 is connected through an elongate conduit 182 interconnected 
at its distal end with a diaphragm connector 184. The flexible diaphragm 
164 comprises a thin, flexible 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 
collection bag 22. It has a relatively large inlet opening at the ends of 
a mounting collar 186 which is resiliently secured around the annular 
diaphragm mounting portion 144 of the connection assembly 32. At its other 
end, it has another annular collar 188, opening in a direction opposite to 
that of collar 186 and having a relatively smaller diameter to resiliently 
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 94, it is fixedly held to arms 46 and 
48 which, in turn, are connected with a weight transducer which responds 
to the total force imposed upon arms 46 and 48. Ideally, 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 connected to the end 
166 of the drainage tube for receipt of the urine, and in the absence of a 
force isolation system, forces are imposed through the drainage tube 30 
which are transmitted to arms 46 and 48 and thereby introduce error into 
the weight calculation. 
The arms 46 and 48 are caused to move downwardly by the weight of the urine 
being collected, but the end 166 of drainage tube 30 is held stationary 
relative to the housing frame 36 of the AUOM unit 20 by means of the 
mating insertion of sensor probe guides 42 and 44 within guide connectors 
104 and 106. Thus, forces applied to the end 166 of the drainage tube 30 
are borne by the AUOM unit 20 and they are not transmitted to the header 
assembly 94. The flexible diaphragm 164 is then the only element which can 
transmit extraneous forces through the weighing mechanism. However, the 
flexible diaphragm is purposely selected to be so flexible that it is not 
capable of sustaining or supporting any significant forces either in a 
direction along its principal axis 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 collection bag 22 are free to move relative to the frame 36 in 
substantial isolation from any forces from the urinary delivery system 
from the patient to the collection bag 22. 
Referring particularly to FIGS. 5A 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 thereby slightly above restraint 
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 
of sampling chamber housing 172, causing the inlet opening at diaphragm 
collar 186 to move closer to the outlet opening at diaphragm collar 188. 
This relative movement is not significantly resisted by the concave wall 
190 which forms a downwardly facing cuff within the space 195 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 184 are moved 
relative to one another. 
Referring still to FIGS. 5A and 5B, particularly FIG. 5A, the diaphragm 
connector 184 carries a stop member 194 which is engageable in blocking 
relationship with the underside 196 of restraint portion 146 to restrain 
relative movement between the inlet and outlet connectors of the flexible 
diaphragm 164 beyond a preselected limit. Movement beyond this limit would 
cause the transmission of force to the header assembly 94 through means of 
the connector assembly 136 or which would stretch or otherwise damage the 
flexible diaphragm 164. 
As best seen in FIG. 6, the force isolation system 26 also includes means 
for restraining relative rotary movement between the ends of the flexible 
diaphragm which would twist it beyond a preselected limit. The rotary 
restraint is provided by means of a pair of radial blocking members 198 
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 212 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 described. Each of the arms 46 and 48 are mirror images of one 
another and have a manually engageable portion 220 which extend through 
the associated female connector 96 and 98 for access at the front of the 
collection bag 22. Both 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 and 48, when in a neutral, or unflexed, 
condition, is greater than the distance D between a pair of inwardly 
facing interlock surfaces 226 and 228 of female 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 surfaces 238 and 240 and a pair of 
interlock surfaces 222 and 224 of arms 46 and 48, respectively, which 
matingly 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 236 carried thereby 
respectively engage interlock surfaces 222 and 224 and are thereby 
gradually, resiliently cammed together 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 assembly 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 position, 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 of 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 spring 246 associated with a pusher member 
248 mounted within a cylindrical housing 250. This pusher member causes 
the female connectors 96 and 98 to automatically, slideably move off of 
interlocking engagement with arms 46 and 48 when the distance between cam 
surfaces 238 and 240 is less than the distance D between the interlock 
surfaces 226 and 228 of the connectors. Thus, the connectors are 
automatically disengaged from arms 46 and 48 simply by manually squeezing 
the manually accessible portions 220 together from the interlock position 
to the release position. 
Referring to FIGS. 8A through 11B, alternate embodiments of the flexible 
diaphragm and associated connectors of the force isolation systems are 
schematically illustrated. In FIGS. 8A and 8B, a flexible diaphragm 252 is 
shown with an inlet 254 and outlet 256 of approximately the same diameter 
and which has substantially straight walls rather than concave walls, as 
in the preferred embodiment of FIGS. 4, 5A and 5B. 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 faces 
upwardly toward the inlet connector 258. As the collection bag 22 fills, 
the outlet connector 260 moves downwardly closer to the inlet connector 
258, as shown in FIG. 8B. 
Referring to FIG. 9A and 9B, another embodiment of a flexible diaphragm 264 
is shown under circumstances of a relatively empty and relatively full 
urinary collection bag 22, respectively. 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 of 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 full extension, the 
flexible diaphragm 264 has a conical shape, as shown in FIG. 9B. Unlike 
the embodiments of FIGS. 8A and 8B and FIGS. 5A and 5B, the inlet is 
located above the outlet in the embodiment of FIGS. 9A and 9B. 
Referring now to FIGS. 10A and 10B, another embodiment of a flexible 
diaphragm 276 is shown in which an inlet end is connected to an inlet 
connector 278 by means of a collar 280, and the outlet end has a collar 
282 which is held between a pair of outlet connector members 284. An 
upturned cuff 286 faces the inlet connector 278, and when the flexible 
diaphragm 276 is extended, as shown in FIG. 10B, the cuff 286 moves 
upwardly until a conical configuration is obtained, as shown. 
Referring now to FIGS. 11A and 11B, yet another embodiment of a flexible 
diaphragm 288 is shown similar to that of FIGS. 10A and 10B but in which 
the body of the flexible diaphragm is bell shaped when extended, as shown 
in FIG. 11B, and which has a laterally extending collar 290 attached to a 
laterally extending outlet connector 292 instead of the vertically 
extending collar and outlet connector of FIG. 10A. Like FIG. 10A, an 
upturned cuff 294 is formed when the inlet connector 292 and an outlet 
connector 296 are spaced from one another as shown in FIG. 11A. 
Referring to FIG. 12, a schematic illustration of yet another embodiment of 
the force isolation system 26 is shown in which the flexible diaphragm 298 
is generally cylindrical and does not form either an upturned or a 
downturned cuff, but merely folds in a random or accordian fashion, as 
shown. The outlet connector 300 directly attaches the outlet of the 
flexible diaphragm 298 to an inlet 302 of the flexible bag 22 located at 
the top 304 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 isolation system, an improved method of weighing urine 
collected from a patient is provided. In prior weighing systems, because 
of the unknown magnitude of extraneous forces applied to the collection 
bag and weighing apparatus by the urine delivery system, urine entered 
into the collection bag upon catherization and before mounting of the 
collection bag to the weighing apparatus, was not accurately weighed. It 
is not accurately weighed in prior devices because of the need of first 
zeroing the weighing apparatus to insure the degree of accuracy needed for 
flow rate and other measurements. Offsetting 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 mounting 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 bag 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 of 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 22 and the end 
166 of tube 30, (d) attaching the bag 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 weighed because the weighing 
apparatus is not zeroed to cancel out the weight of this previously 
collected urine. Accordingly, the AUOM unit weighs it together with the 
urine subsequently collected to give a combined weight or volume 
indication. 
While a particular embodiment has been shown, it should be appreciated that 
variations may be made with regard thereto without departing from the 
scope of the invention. For instance, although a flexible plastic 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 systems for other 
types of biological fluids, such as blood. Thus, the scope of the 
invention is defined by the following claims and not by the foregoing 
detailed description of the preferred embodiment.