GAS-DISABLED LIQUID-PUMPING APPARATUS

• US 3,620,650 A
• Filed: 12/05/1969
• Issued: 11/16/1971
• Est. Priority Date: 12/05/1969
• Status: Expired due to Term

• Current Assignee: Abbott Laboratories Incorporated
• Original Assignee: 94117,, Robert F. Shaw, 350 Parnassus Heights
• Inventors: Robert F. Shaw, 350 Parnassus Heights, 94117,
• Primary Examiner(s): Robert M. Walker
• Application Number:
  US04/882,489
• Time in Patent Office: 711 Days
• Field of Search: 417/417,435,476,559,443,478,490,392,393,394,395 184/29 222/334,249
• US Class Current: 417/417
• CPC Class Codes: A61M 5/14216 Reciprocating piston type
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: A61M 5/36 with means for eliminating or preventing injection or infusion of air into body dialysis systems, blood oxygenators A61M1/14; haemofiltration equipment A61M1/34; automatic tube cut-off A61M39/281
• CPC Class Codes: F04B 17/048 the fluid flowing around the moving part of the motor
• CPC Class Codes: F04B 43/08 having tubular flexible members F04B43/12 takes precedence
• CPC Class Codes: F04B 7/04 in which the valving is performed by pistons and cylinders coacting to open and close intake or outlet ports
• CPC Class Codes: Y10S 128/13 Infusion monitoring

Abstract

Improved liquid-pumping apparatus uses a pumping chamber having a residual volume many times larger than the displacement volume and includes an outlet valve which is disposed within the lowermost region of the residual volume and which is biased against outflow of fluid therethrough for fluid pressures below a selected value.

Claims

1. Liquid infusion apparatus for selectively pumping a system in which gas may be present, the apparatus comprising:

a pumping chamber for enclosing a volume of fluid, and having an outlet valve which is biased against outflow of fluid therethrough for fluid pressures below a selected value, said outlet valve being disposed to remain in communication only with liquid in the chamber in the presence of gas therein;

means communicating with said chamber for decreasing the volume thereof by a selected displacement volume during a liquiddisplacement period which preserves a residual volume of the chamber that is greater than said selected displacement volume; and

inlet means communicating with said chamber and adapted to receive a supply of liquid at an ambient pressure which is below said selected value, said inlet means permitting bidirectional fluid passage therethrough into said chamber between liquid-displacement periods for substantially equalizing fluid pressure within the chamber to ambient pressure prior to a liquid-displacement period and preventing outflow therethrough from said chamber during the liquiddisplacement period.

2. Liquid infusion apparatus as in claim 1 wherein:

the ratio of volume of said pumping chamber to volume of said displacement volume is greater than the ratio of the value of said fluid pressure bias provided by said outlet valve plus atmospheric pressure to the value of said fluid bias pressure.

3. Liquid infusion apparatus as in claim 2 wherein:

the selected value of fluid pressure bias provided by said outlet valve is greater than 3 pounds per square inch gauge pressure.

4. Liquid infusion apparatus as in claim 2 wherein:

said selected value of fluid pressure bias provided by said outlet valve is approximately 5 pounds per said inch gauge pressure; and

manipulatable outlEt said residual volume of the chamber is at least approximately four times greater than said selected displacement volume.

5. Liquid infusion apparatus as in claim 1 comprising:

means coupled to said chamber in the lowermost region of the residual volume thereof adjacent to said outlet valve for releasing gas from said chamber to establish communication between liquid in said chamber and said outlet valve.

6. Liquid infusion apparatus as in claim 5 wherein:

said means coupled to said chamber includes a manually manipulatable element which is manually movable from a normally operational position to a position which disables the outlet valve from establishing said selected value of fluid pressure bias; and

resilient biasing means coupled to said element for urging said element into said normally operational position following release thereof from manually applied forces to provide fail safe reestablishment of said selected value of fluid pressure.

7. Liquid infusion apparatus as in claim 5 wherein:

said means coupled to said chamber includes a manually manipulatable element which is manually movable from a normally operational position to a position which disables the outlet valve from establishing said selected value of fluid pressure bias, and further includes means cooperating with said element for preventing normal operational communication between the chamber and said means for decreasing the volume thereof in response to said element being improperly positioned to establish said selected value of fluid pressure bias.

8. Liquid infusion apparatus as in claim 1 wherein:

said inlet means includes a reserve chamber having a port passing between said chamber and said reserve chamber and having a volume greater than said residual volume, said port blocking outflow of fluid therethrough from said chamber during said liquid-displacement period.

9. Liquid infusion apparatus as in claim 1 wherein:

said means communicating with said chamber includes a piston which forms a fluid-confining boundary of said chamber and which is longitudinally movable within said chamber; and

said inlet means includes a fluid channel within the wall of the chamber positioned with respect to said piston for passing fluid therethrough into said chamber while said piston is disposed at a position along the path of longitudinal movement prior to said liquid-displacement period and for blocking fluid flow out of said chamber in response to movement of said piston along said path during said liquid-dsiplacement period.

10. Liquid infusion apparatus as in claim 9 wherein:

said means communicating with said chamber includes an element of magnetic material coupled to said piston and a source of magnetic flux disposed with respect to said element for repetitively altering the position thereof and of the piston coupled thereto.

11. Liquid infusion apparatus as in claim 1 wherein:

said means communicating with said chamber includes extensible boundary walls which define said chamber;

said inlet means includes an aperture through the upper wall into the chamber, valve means disposed about said aperture for permitting fluid flow therethrough into said chamber for a selected longitudinal extension of said sidewalls, and for preventing fluid flow therethrough during decrease of the volume of said chamber in response to movement of the extensible sidewalls; and

actuating means coupled to said sidewalls for cyclically moving the extensible boundary walls between selected dimensions at a predetermined repetition rate.

12. Liquid infusion apparatus as in claim 1 wherein:

said chamber includes a selected length of resilient flexible tubing having an internal fluid-confining passage therethrough of substantially uniform cross section along the length thereof;

said means communicating with said chamber includes a rotatable actuator having at least one element which is disposed with respect to said tubing for squeezing the saMe to close the passage therethrough, and which is responsive to rotation of said rotatable actuator for altering the location of the squeeze of the tubing over a selected portion of the length of said tubing between a first limit near a fluid inlet end to said internal passage and a second limit remote from the first limit; and

said outlet valve includes another actuator resiliently biased to squeeze said tubing to close the passage therethrough at a location along the tubing remote from the fluid inlet end thereof and spaced from said second limit by a distance greater than the distance along said selected portion of the tubing between the first and second limits, said other actuator squeezing said tubing thereby establishing said selected value of fluid pressure bias.

13. Liquid infusion apparatus as in claim 12 wherein:

said rotatable actuator being disposed with respect to said tubing to provide during a portion of the rotational cycle thereof an unclosed internal passage through said tubing from the fluid-inlet end thereof to said other actuator, and thereafter to provide during another portion of the rotational cycle thereof a closure of the internal passage through the tubing at a location therealong with advances over said selected portion of length from said first limit to said second limit in response to rotation of said rotatable actuator.