Fluid flow control apparatus

A reservoir outlet control device for controlling fluid flow from a reservoir. The device is particularly suitable for controlling fluid outflow from a blood collecting and blood delivery reservoir.

BACKGROUND OF THE INVENTION 
The present invention relates generally to fluid flow control and, more 
particularly it relates to a device for controlling the flow of fluid out 
of a fluid collection reservoir. The device is especially suitable for use 
in the control of the outflow of blood from a blood collection and 
transfer reservoir. 
There have been introduced into the marketplace a number of direct whole 
blood cardiotomy reservoirs and methods for using reservoirs during the 
recovery and collection of blood for subsequent return to a patient. 
Typically, a system might utilize a negative pressure source for blood 
delivery and collection in a reservoir and use the force of gravity for 
return of the collected blood to the patient. Alternatively, instead of 
using gravity for blood return, for example, a roller pump or an 
intravenous pump might be used for reinfusion of collected blood to 
increase the rate of blood return to the patient. Another technique might 
be the delivery (under positive pressure) to the patient of blood 
previously collected from the patient or delivery (also under positive 
pressure) to the patient of donor blood. In each system, extreme caution 
must be exercised to prevent the inroduction of air into the patient 
return or delivery line, the presence of which could create an air 
embolism endangering the patient. 
Disclosure of a blood collection and delivery apparatus can be found in 
U.S. Pat. No. 3,896,733. In this device, there is employed in each of two 
blood collection chambers a float valve which moves with the level of 
blood fluid in the chamber. The operation of the float valve is governed 
solely by the rise and fall of the level of blood in the chamber. 
Specifically, when the fluid in the chamber drops to the level of the 
valve seat at the bottom of the chamber, the valve sinks into sealing 
engagement with the valve seat to close off the fluid outlet from the 
chamber. The valve, which takes the form of a floating disc, is designed 
to prevent air from entering the chamber outlet. When fluid is again 
introduced into the chamber, the float valve is designed to rise with the 
rising fluid level. 
A primary disadvantage of the aforementioned fluid outflow control system 
is that, should the floating disc not be properly seated, then air could 
enter the chamber outlet line leading to the patient. Improper seating 
could result should the floating disc become tilted or askew, for example, 
perhaps resulting from material buildup on the valve seat, material 
buildup on the blood surface or material buildup along the chamber wall. 
Coagulating blood could also cause disc tilting and result in an improper 
outlet seal. Due to the complex nature and makeup of blood, one or more of 
these undesirable situations could occur and result in air passage into 
the patient line, particularly when the floating valve depends solely upon 
the fluid level and incorporates no additional feature to positively urge 
the valve into sealing engagement with the valve seat. 
The primary objective of the present invention is to advance the art field 
by providing a reliable reservoir fluid outlet control device, 
particularly a device suitable for controlling blood outflow from a blood 
collection reservoir, for releasably sealing the reservoir outlet against 
fluid passage therethrough. Accordingly, herein disclosed is a reservoir 
outlet control device which is especially designed and configured to 
provide a positive force for urging the outlet control device into a fluid 
sealing position at a predetermined fluid level in the reservoir and for 
preventing air entry into the patient delivery line. 
SUMMARY OF THE INVENTION 
The present invention is directed toward a reservoir outlet control device 
for controlling fluid flow from a reservoir outlet port comprising a 
member being movable responsive to a level of fluid in the reservoir, 
means for releasably sealing the outlet port against fluid flow, means for 
releasing the outlet port seal, and means for first maintaining an open 
outlet port above a predetermined level of fluid in the reservoir and then 
for reestablishing the outlet port seal. The device might further include 
biasing means for urging the sealing means toward a reservoir outlet port 
sealing position. The reservoir fluid might be blood, might at least be 
partially blood, or might be any liquid for delivery to a living body. 
Furthermore, the fluid leaving the reservoir might be pressurized. The 
member might be a float and the sealing means might further include an 
arm. The sealing means might comprise a self aligning seal which could 
take the form of a cup-shaped suction disc. In one embodiment, the arm 
might be a resilient member. In another embodiment, the arm might further 
include means for preventing movement of the arm when the fluid in the 
reservoir is below a predetermined level. 
Also included to be within the scope of the invention, in one embodiment, 
is an outlet control device for controlling the flow of blood from a blood 
collecting and delivery reservoir comprising float means being movable 
responsive to a level of blood in the reservoir, lever means including 
means for sealing the reservoir outlet against blood flow therethrough, 
means for displacing the lever means to a position releasing the reservoir 
outlet seal, and means for holding the lever means in the seal releasing 
position until a predetermined level of blood remains in the reservoir and 
thereafter freeing the lever means for reestablishing the outlet seal. The 
lever means might be a resilient member. The float means and the lever 
means cooperatively engage one another until the predetermined level of 
blood remains in the reservoir, below which level, the float means and the 
lever means disengage to restore the seal. The device might further 
include means for preventing displacement of the lever means when the 
blood is below the predetermined level. The device further includes means 
for activating the lever displacing means and means for returning the 
lever displacing means to a preactivating position. The lever displacing 
means might be a pawl adapted to engage a tab on the lever means. 
Additionally, there might be included means for guiding the movement of 
the pawl and means for disengaging the pawl and the tab. The blood leaving 
the reservoir might be pressurized and the sealing means might comprise a 
self aligning seal, such as a cup-shaped suction disc. Lastly, the device 
might further include biasing means for urging the lever means toward a 
reservoir outlet sealing position. 
The invention further embodies a blood collection reservoir comprising a 
housing having an inlet, a collection chamber and an outlet, and means for 
controlling the flow of blood through the outlet, the flow control means 
comprising float means being movable responsive to a level of blood in the 
reservoir, lever means including means for sealing the reservoir outlet 
against blood flow therethrough, means for displacing the lever means to a 
position releasing the reservoir outlet seal, and means for holding the 
lever means in the seal releasing position until a predetermined level of 
blood remains in the reservoir and thereafter freeing the lever means for 
reestablishing the outlet seal. The lever means might preferably be a 
resilient member. The reservoir might further include biasing means for 
urging the lever means toward a reservoir outlet sealing position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The description herein presented refers to the accompanying drawings in 
which like reference numerals refer to like parts throughout the several 
views. First, turning to FIG. 1, there is illustrated a partial sectional 
view of a multicompartmental blood collection reservoir 10 having housing 
wall 12, blood transfer chamber 14 and an outlet control device generally 
designated as 16. Reservoir 10 is shown as it would appear prior to usage. 
There is a compartment above chamber 14 from whence collected blood is 
transferred to chamber 14. It should be understood that, while the term 
blood is herein used, the collected fluid could, for example, be 
substantially whole blood or at least partially whole blood. Furthermore, 
the fluid could include saline, irrigation fluid, heparin or other fluids 
associated with surgical procedures. The fluids which leave the reservoir 
are suitable for ultimate delivery to a living body. It should be 
understood that, while a multicompartmental blood collection reservoir 
will be described, a reservoir having one compartment would be suitable 
for the collection of blood and other fluids. Likewise, reservoir 10 is 
suitable for handling fluids other than blood. Reservoir 10 further 
includes outlet 18, valve 20, seal ring 22, rod 24, blood filter 26, 
trigger 28, spring 30 and handle 32. Trigger 28 is pivotally connected to 
reservoir 10 by pin 29 and further engages rod 24 at a location not herein 
shown. A compression spring or the like (not shown) could be used in place 
of the spring configuration designated 30. The spring is designed to 
return trigger 28 to its preactivation position. 
Outlet control device 16 has a number of interrelated components. A first 
component is float 34 which is pivotally connected to the reservoir by pin 
36. The next component is lever 38 which is pivotally connected to the 
reservoir by pin 40, with lever 38 including valve 42 configured to engage 
outlet 18 to seal the outlet at a valve seat generally designated as 44. 
Lever 38 further includes projecting post or tab 46. Another component 
includes actuator 48, which is connected to rod 24, with the actuator 
further engaging pawl 50 via pin 51. A pin 52 connects pawl 50, with pin 
52 shown as being located in member 53 having slot 54, and it is the 
cooperative action of pin 52 and slot 54 which guides the movement of the 
pawl. Lastly, there is spring 56 which engages lever 38 to bias the lever 
toward a reservoir outlet sealing position. Float 34 further includes a 
surface 49 which, in FIG. 1, is shown positioned to stop the downward 
movement of actuator 48. Surface 49 is designed to obstruct a continued 
movement of actuator 48 when the surface and actuator engage one another. 
Thus, without a predetermined level of fluid in reservoir chamber 14, the 
outlet seal cannot be inadvertently broken. 
Turning now to FIGS. 2 through 5, there are shown, sequentially, views of 
the reservoir and outlet control device in operation. A person, placing 
handle 32 in the palm of a hand and with fingers extending around trigger 
28, could exert a force F on trigger 28 and cause displacement of the 
trigger as shown in FIG. 2. This displacement of trigger 28, pivoting 
about pin 29, causes compression of spring 30 (not shown in this view) and 
the downward movement of rod 24, valve 20, actuator 48 and pawl 50. As the 
seal between valve 20 and seal ring 22 is broken, blood B (or other fluid) 
is allowed to enter chamber 14 from a compartment above chamber 14 where 
blood had previously been collected. The blood being collected in chamber 
14 rises and causes float 34 to rotate and rise accordingly. The rotation 
of float 34 causes surface 49 to rotate to a position wherein surface 49 
will no longer obstruct the downward movement of actuator 48. There is now 
a clearance between the rightmost end portion of actuator 48 and surface 
49. Pawl 50 engages tab 46 on lever 38 but, in this view, as yet the lever 
remains stationary. Outlet 18 remains sealed as valve 42 remains seated on 
valve seat 44. Spring 56 biases lever 38 and valve 42 toward an outlet 
closing position. No blood flows through outlet 18. Valve 42 is herein 
shown as a stopper but, preferably, it could take the configuration of a 
cup-shaped suction disc which would present a seal having a self aligning 
feature. 
Turning next to FIG. 3, upon release of force F compressed spring 30 (not 
shown) urges trigger 28, rod 24, valve 20, actuator 38 and pawl 50 to 
return their original positions shown in FIG. 1. The seal between valve 20 
and seal ring 22 has been reestablished to block the further inflow of 
blood into chamber 14. Float 34 has further risen as the level of blood in 
chamber 14 has increased. Also the seal between valve 42 and seat 44 has 
been broken to allow blood to flow out of chamber 14 through outlet 18 for 
delivery to a patient or to another storage compartment. The upward 
movement of actuator 48 and pawl 50, the pawl having been engaged with tab 
46 as shown in FIG. 2, first causes the upward displacement of lever 38, 
as the lever pivots about pin 40, resulting in the unsealing of outlet 18. 
Thereafter, pawl 50 and tab 46 disengage and lever 38, being biased by 
spring 56, attempts to return valve 42 to seat 44 to close outlet 18. (The 
operation of pawl 50 and lever 38 is shown in greater detail in FIGS. 
8-11). However, float 34 and lever 38, at end location generally 
designated as 58, cooperatively engage one another to prevent lever 38 
from returning to its outlet sealing position. Float 34, being bouyed by 
the level of blood in chamber 14, resists the counterclockwise movement of 
lever 38 at contact location 58 and the outlet remains open allowing 
passage of blood therethrough. Although not shown in these views, transfer 
chamber 14 could be pressurized so that the fluid leaving outlet port 18 
is under a pressure above atmospheric. A port could be established in wall 
12 and, for example, a sphygmomanometer bulb, a pressure gauge and tubing 
communicating with the port could be used to establish desired pressure 
levels. 
Next, we turn to FIG. 4 and observe that outlet 18 remains open to blood 
outflow, the level of blood in chamber 14 has dropped, float 34 has 
rotated counterclockwise responsive to the lowered blood level and that 
float 34 and lever 38 remain in contact at location 58 thus preventing the 
return of valve 42 to seat 44. FIG. 5 shows yet the further lowering of 
the blood level in chamber 14 and that float 34 and lever 38 remain in 
engagement at location 58 to keep outlet 18 open. It should be observed 
that contact between the float and lever at location 58 is about to be 
broken. Lastly, we turn to FIG. 6 and observe that there is no longer 
contact between float 34 and lever 38 at location 58 and that lever 38, 
being biased by spring 56, has further rotated to return valve 42 to seat 
44 to thereby seal outlet 18 against further blood outflow. It should be 
observed that a level of blood remains above the closed outlet port to 
insure that no air is allowed to pass through outlet 18. The sequences 
depicted in FIGS. 2 through 6 can now be repeated. 
FIG. 7 shows yet another embodiment of outlet control device 16. Here the 
outlet control device has been designated 16', the float 34', the float 
pivot pin 36', the lever 38', the tab 46', the surface for obstructing 
movement of actuator 48 has been designated 49', and the location wherein 
float 34' and lever 38' engage has been designated 58'. Lever 38' is a 
resilient member, perhaps a leaf spring or the like, connected to the 
reservoir by rivet 60. Operation of outlet control device 16' is 
substantially as hereinbefore described with respect to device 16. 
Movement of actuator 48 and pawl 50 to engage tab 46' and open outlet port 
18 and raise lever 38' has been completed. Here as the level of blood B 
drops, float 34' rotates in a clockwise direction about pivot 36'. At 
location 58', triangulated section 62 of float 34' and triangulated 
section 64 of resilient member 38' are slidingly engaged to maintain 
outlet port 18 open, that is, lever 38' is releasably held in the position 
down. As float 34' continues its clockwise rotation as the blood level 
drops, sections 62 and 64 will slide past one another and lever 38', 
released from its raised position, will move downwardly and valve 42 will 
engage valve seat 44 to seal outlet port 18 against further blood outflow. 
As before, a level of fluid will remain above closed outlet port 18. 
Thereafter, the fill and discharge cycle of transfer chamber 14 can begin 
anew. 
FIGS. 8-11 schematically show the operation of the pawl as it is used to 
engage and displace the lever arm. The line of sight is looking basically 
at the pawl from right to left. FIG. 8 shows pawl 50 substantially in the 
position of FIG. 1, that is, at least prior to activation of the pawl. The 
downward and outward movement of pawl 50 will be governed by movement of 
pin 52 traveling along slot 54. FIG. 9 shows the pawl just prior to 
engagement with tab 46 and shows, in phantom, the pawl in latching 
engagement with tab 46 (as shown in FIG. 2). In FIG. 10, pawl 50 is in 
engagement with tab 46 and is about to move upwardly. Upward movement of 
pawl 50 latched to tab 46 will cause upward displacement of lever arm 38 
and the opening of outlet port 18. FIG. 11 shows the rocking motion of 
pawl 50 and the release of tab 46. Lever 38 will basically be in the 
position shown in FIG. 3. Pawl 50 will continue moving upwardly to return 
to the position shown in any of FIGS. 1 and 3-8. 
The present invention has been described herein with specific reference to 
the preferred embodiments thereof. However, those skilled in the art will 
understand that changes may be made in the form of the invention covered 
by the claims without departing from the scope and spirit thereof, and 
that certain features of the invention may sometimes be used to an 
advantage without corresponding use of the other features.