Pump For Blood Plasma And The Like

Abstract

A pump for plasma and the like is provided suitable for use with but not confined to available plasma containers and with the rate of discharge maintained constant but adjustable over a wide range, the pump being portable and self-contained, with accessibility to the components, and having a fluid transferring spring-impelled piston driving a pressure plate which is manually reset by a handle for each operation. The pump is independent in operation, of temperature, weather conditions, altitude, orientation, and whether it is in motion or at rest.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to pumps for fluids which are particularly suited for blood plasma and the like and more particularly to such pumps having an adjustable predetermined delivery rate.

2. Description of the Prior Art

It has heretofore been proposed to provide self-contained pumps for blood plasma and the like, the patents to Kralsauer et al., U.S. Pat. No. 3,375,824 and Tomlinson U.S. Pat. No. 2,703,084 being illustrative.

The devices heretofore proposed had various shortcomings, including complexity of construction, difficulty of access to components and lack of reliability over a wide range of conditions encountered in use in the field.

SUMMARY OF THE INVENTION

In accordance with the invention a pump for plasma and the like is provided suitable for use with but not confined to available plasma containers and with the rate of discharge maintained constant but variable over a wide range, the pump being portable and self-contained with accessibility to the components, and having a fluid transferring spring-impelled piston driving a pressure plate which is manually reset by a handle for each operation. The pump is independent, in operation, of temperature, weather conditions, altitude, orientation, and whether it is in motion or at rest.

It is the principal object of the present invention to provide an improved pump for plasma and the like which can utilize but is not limited to presently available plasma containers and with which a constant delivery at a selected flow rate is attained.

It is a further object of the invention to provide a pump for plasma and the like which is portable and does not require any outside source of power so that it can be used and reused in the field.

It is a further object of the present invention to provide a pump for plasma and the like which will be free from operating difficulties and which can be operated by relatively unskilled persons.

It is a further object of the present invention to provide a pump for plasma and the like which can be easily started and stopped and which can be easily adjusted for the desired rate of delivery.

Other objects and advantageous features of the invention will be apparent from the description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The nature and characteristic features of the invention will be more readily understood from the following description taken in connection with the accompanying drawings forming part thereof, in which:

FIG. 1 is an external side elevational view of a pump in accordance with the invention;

FIG. 2 is a vertical sectional view taken approximately on the line 2--2 of FIG. 3;

FIG. 3 is a horizontal sectional view taken approximately on the line 3--3 of FIG. 2;

FIG. 4 is a fragmentary sectional view, enlarged, showing one end of the piston rod and the guide therefor;

FIG. 5 is a detail sectional view of the piston rod and guide assembly, and

FIG. 6 is a schematic view showing the fluid connections for the pump.

It should, of course, be understood that the description and drawings herein are illustrative merely, and that various modifications and changes can be made in the structure disclosed without departing from the spirit of the invention.

Like numerals refer to like parts throughout the several views.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now more particularly to the drawings in which a preferred embodiment of the invention is illustrated a casing 10 is provided which includes a longitudinal bottom support plate 11, to which a one piece housing having vertical sidewalls 12 and 13, a stationary vertical end wall 14 and a vertical end closure plate 15 is removably secured by stud bolts (not shown).

An interior transverse vertical support plate 16 affixed to support plate 11 is provided, in spaced relation to the end closure plate 15. An interior transverse vertical support plate 14a is affixed to support plate 11 in spaced relation to end closure plate 14.

A U-shaped handle 20 is provided extending through the sidewalls 12 and 13 and connected to a drum 21 carried by brackets 22 secured to the support plate 11. The handle 20 is effective for rotating the drum 21 through a predetermined angle as hereinafter explained.

The support plate 16 has a horizontal cylinder 25 secured thereto with a piston 26 therein carried on a piston rod 27. The periphery of the piston 26 in contact with the interior wall of the cylinder 25 is preferably provided with a packing 28 which may be an O-ring.

The piston rod 27 extends through a packing 29 in an end wall 30 of the cylinder 25 and is connected to a vertical pressure plate 31 which is movable within the casing 10 toward and away from the end plate 14a. A sling 32 of elastic material is provided connecting the pressure plate 31 and the wall 14a to provide a compartment 33 variable in size as determined by the movement of the piston rod 27 and confined by the sidewalls 12 and 13.

For the purpose of delivering plasma, a flexible plasma container 35 of any desired type and of adequate strength is provided, the structure being particularly suitable for use with the well known "Fenwal Blood Pak." The container 35 has a delivery tube 36.

The pressure plate 31 on a bottom side has flexible cable 37 secured thereto and extending to and secured to the drum 21 and flexible cable 38 secured thereto on a top side and extending over guide pulley 39 to the drum 21 to which they are secured. Rotation of the drum 21 by the handle 20 tends to retract the pressure plate 31 and move it away from the wall 14a. Braces 32 may be provided connecting the wall 14a and the support plate 16.

A compression spring 40 within the cylinder 25 and bearing on the piston 26 and an end wall 41 of the cylinder 25 urges the piston rod 27 and the pressure plate 31 in a direction to compress the plasma container 35.

In order to control the movement of the piston 26 a fluid system is provided which includes a fluid connection 43 to the cylinder 25 which is connected through a manually adjustable control valve 44, through a flow controller 45, and a manually operable stop valve 46 in a fluid connection 47 extending to the other end of the cylinder 25. The control valve 44 has an exteriorly accessible manual operating handle 48 and the stop valve 46 has an exteriorly accessible manual operating handle 49.

The flow controller 45 can be of any desired type which will maintain a constant differential pressure across the control valve 44. A suitable flow controller for this purpose, is available from Moore Products Co., Spring House, Pa. and is illustrated in U.S. Pat. No. 2,627,281.

A fluid bypass connection 50 is provided, connecting the fluid connections 43 and 47 with a nonreturn or check valve 51 therein permitting flow of fluid from the fluid connection 43 to the fluid connector 47 but not permitting flow in the opposite direction, such flow in the opposite direction being through the flow controller 45 as determined by the valves 44 and 46.

The handle 48 of the control valve 44 is on a valve stem 53 which carries a pulley 54. The pulley 54 is connected by a cable 55, to a pulley 56 on the shaft 57 of a flow indicator 58.

The piston rod 27, as shown in detail in FIG. 5 has a hollow extension 60 which is engaged in a guide 61, secured to the cylinder wall 41. The guide 61 is provided with an orifice 62 which is of a predetermined size to prevent fluid flow into the interior of the guide at an excessive rate. The rate of flow for plasma pumping in a particular embodiment is not in excess of 103.5 ml. per minute. The guide 61 also carries a check valve 63 which permits more rapid discharge upon movement of the handle 20 for cocking.

The fluid system which includes the cylinder 25, fluid connectors 43, 47 and 50, the flow controller 45 and the valves 44 and 46 is preferably liquid filled, with a liquid such as alcohol, ethyleneglycol or light oil which will not freeze and which will be effective over a wide range of atmospheric temperatures, frigid as well as tropical, as required.

The mode of operation will now be pointed out.

In order to deliver plasma from the plasma container 35 through the delivery tube which in a preferred embodiment is in the range from 1.08 ml. per minute (8 hours per charge) to 103.5 ml. per minute (5 minutes per charge), the handle 20 is moved from the upright solid line position shown in FIG. 1 to the dotted position.

Movement of the handle 20 through the arc indicated is effective to wind the cables 37 and 38 onto the drum 21 and move the pressure plate 31 away from the wall 14a so that a previously emptied container 35 can be removed and full container 35 inserted in the compartment 33.

With stop valve 46 closed, the pressure plate 31 is moved by the cables 37 and 38, the spring 40 is compressed by movement of the piston 26, and fluid at the spring side of the piston 26 is forced through the fluid connection 43, the bypass connection 50 and check valve 51 through the fluid connection 47 to the opposite side of the piston 26. As this occurs fluid in the guide 61 and extension 60 is discharged through the check valve 63.

As the spring 40 now urges the piston 26 and the pressure plate 31 to compress the container 35 in the compartment 33 the stop valve 46 is opened and the control valve 44 is positioned in accordance with the rate of flow desired. This setting of the valve 44 and the rate of flow will be indicated at the flow indicator 58 and will be maintained by the flow controller 45 is as determined by the setting of the control valve.

The size of the orifice 62 provides an upper limit on the movement of the piston 26 and the displacement of fluid by such movement.

Upon completion of the compressing movement of the pressure plate 31, the pressure plate 31 can be retracted by closure of valve 46 and by positive movement of the handle 20, full movement being affected if another plasma container 35 is to be inserted in the compartment 33 for use.

The handle 20, in addition to its purpose of cocking the apparatus for initiation of delivery also serves as a carrying handle if desired. A force of approximately 10 pounds will supply the desired positioning of the piston 26.

The pump in use will maintain the desired constant flow rate of plasma as established by the positioning of valve 44 and without further adjustment even though the pump is relocated to as much as 4 feet below the plasma recipient, or relocated above the recipient, or placed on the same level as the recipient, or if the pump and recipient are in transport at varying barometric pressures.

It will thus be seen that apparatus has been provided for effecting the objects of the invention.

Claims

I claim:

1. Apparatus for delivering fluent materials from a disposable flexible fluid container comprising

a casing having a fixed wall and a pressure applying plate member movable with respect to said wall and providing with said wall a compartment for the retention of a disposable flexible fluid container,

manually operable means for positioning said pressure applying plate member spaced from said wall in a set position for actuation, and

means for controlling the movement of said pressure applying plate member at a predetermined constant rate from its set position toward said wall for affecting delivery of fluid from said container,

said means for controlling said movement including

a cylinder,

a movable member in said cylinder connected to said pressure applying plate member, and

a closed fluid circuit comprising

fluid connections between the opposite ends of said cylinder, and

members for controlling the flow through said fluid connections.

2. Apparatus as defined in claim 1 in which

said last-mentioned members include a fluid flow controller.

3. Apparatus as defined in claim 2 in which

said last-mentioned members include a manually settable valve across which a constant differential pressure is maintained by said flow controller.

4. Apparatus as defined in claim 1 in which

said means for controlling includes a resilient member having force stored therein by movement of said means for positioning.

5. Apparatus as defined in claim 4 in which

said movable member in said cylinder is a piston, and

said resilient member is disposed in said cylinder and in engagement with said piston.

6. Apparatus as defined in claim 1 in which

said flow controlling members have a bypassing fluid circuit therein, permitting movement for positioning.

7. Apparatus as defined in claim 1 in which

said means other than said means for positioning are mounted in casing, and

said means for positioning includes a handle exteriorly accessible for actuation.

8. Apparatus as defined in claim 7 in which

said handle is connected to a drum, and

flexible members are connected to said drum and to said pressure applying member for moving said pressure applying member to said set position.