Method and device for regulating fluid pump pressures

Patent metadata

Field	Value
Publication number	US-8989906-B2
Application number	US-201414279496-A
Country	US
Kind code	B2
Filing date	May 16, 2014
Priority date	Jul 10, 2000
Publication date	Mar 24, 2015
Grant date	Mar 24, 2015

Abstract

A method is provided for regulating fluid pump pressures by detecting an elevation differential between a fluid flow control device and the distal end of a fluid line in communication with the fluid flow control device. A fluid flow control device, for instance a peritoneal dialysis device, is at a first height, a distal end of a fluid line is at a second height, and a valved outlet, when open, affords communication between the fluid flow control device and the distal end of the fluid line. The elevation differential is correlatable with a pressure measurable during a calibration procedure provided as a part of the methodology.

First claim

What is claimed is:

1. A system for controlling pressure of a liquid at a distal end of a fluid line connected to a liquid pumping apparatus comprising;
a first chamber comprising a first control region separated from a first liquid region by a first flexible membrane, the first control region having a pre-determined minimum volume when the first liquid region has a pre-determined maximum volume when filled with the liquid;
a first pressure transducer configured to measure a pressure of the first control region when the first chamber is filled with the liquid;
a second chamber comprising a second control region separated from a second liquid region by a second flexible membrane, the second control region configured for connection to an actuation system comprising a controllable source of positive pressure, negative pressure, or a vent for the delivery of pressure to or venting of the second control region;
a first valve interposed between a first port of the first liquid region and a first flowpath connected to a source of the liquid, a second valve interposed between a first port of the second liquid region and the first flowpath, a third valve interposed between a second port of the first liquid region and a second flowpath connected to the distal end of the fluid line, and a fourth valve interposed between a second port of the second liquid region and the second flowpath; and
a controller configured to receive pressure information from the pressure transducer, to control the valves, and to control the actuation system and pumping of the liquid by the second chamber,
wherein the controller is configured to:
control the opening of the first and second valves, the closing of the third and fourth valves, and control the actuation system to fill the first and second liquid regions with the liquid from the liquid source;
record a first pressure measurement from the first pressure transducer when said liquid regions are filled with the liquid;
control the closing of the first and second valves, the opening of the third and fourth valves, and record a second pressure measurement from the first pressure transducer when said liquid regions are in fluid communication with the distal end of the fluid line; and
adjust the delivery of pressure by the actuation system to the second control region based on a difference between the first and second pressure measurements.

2. The system of claim 1 , wherein the controller is configured to decrease a magnitude of pressure delivered to the second control region if the second pressure measurement is less than the first pressure measurement, and to increase a magnitude of pressure delivered to the second control region if the second pressure measurement is greater than the first pressure measurement, so as to maintain a pressure of the liquid at the distal end of the fluid line within a pre-determined range of a pre-determined value.

3. The system of claim 1 , wherein the controller is configured to control the valves and actuation system to allow filling of the first and second liquid regions by gravity flow.

4. The system of claim 1 , wherein the positive or negative pressure source comprises a gas or liquid under positive or negative pressure.

5. The system of claim 1 , wherein the positive or negative pressure source comprises air under positive or negative pressure.

6. The system of claim 1 , wherein the controller is configured to record a plurality of pressure measurements by the first pressure transducer during emptying or filling of the second liquid region and to regulate pressure delivered to the second control region by the actuation system based on said plurality of pressure measurements.

7. The system of claim 1 , further comprising a second pressure transducer configured to measure a pressure of the second control region when the second liquid chamber is filling with or emptying the liquid, wherein the first control region is configured for connection to the actuation system to allow pumping of the liquid by the first chamber, and wherein the controller is configured to regulate pressure delivered to the first control region based on the pressure measurement by the second pressure transducer.

8. A method for controlling pressure of a liquid at a distal end of a fluid line connected to a liquid pumping apparatus, the liquid pumping apparatus comprising:
a first chamber comprising a first control region separated from a first liquid region by a first flexible membrane, the first control region having a pre-determined minimum volume when the first liquid region has a pre-determined maximum volume when filled with the liquid;
a first pressure transducer configured to measure a pressure of the first control region when the first chamber is filled with the liquid;
a second chamber comprising a second control region separated from a second liquid region by a second flexible membrane, the second control region configured for connection to an actuation system comprising a controllable source of positive pressure, negative pressure, or a vent for the delivery of pressure to or venting of the second control; and
a first valve interposed between a first port of the first liquid region and a first flowpath connected to a source of the liquid, a second valve interposed between a first port of the second liquid region and the first flowpath, a third valve interposed between a second port of the first liquid region and a second flowpath connected to the distal end of the fluid line, and a fourth valve interposed between a second port of the second liquid region and the second flowpath;
the method comprising:
opening the first and second valves, closing the third and fourth valves, and controlling the actuation system to fill the first and second liquid regions with the liquid from the liquid source;
recording a first pressure measurement from the first pressure transducer when said liquid regions are filled with the liquid;
closing the first and second valves, opening the third and fourth valves and recording a second pressure measurement from the first pressure transducer when said liquid regions are in fluid communication with the distal end of the fluid line; and
adjusting the delivery of pressure by the actuation system to the second control region based on a difference between the first and second pressure measurements.

9. The method of claim 8 , wherein adjusting the delivery of pressure to the second control region comprises decreasing a magnitude of pressure delivered to the second control region if the second pressure measurement is less than the first pressure measurement, and increasing a magnitude of pressure delivered to the second control region if the second pressure measurement is greater than the first pressure measurement, so as to maintain a pressure of the liquid at the distal end of the fluid line within a pre-determined range of a pre-determined value.

10. The method of claim 8 , wherein controlling the actuation system to fill the first and second liquid regions with the liquid from the liquid source comprises allowing filling of the first and second control regions by gravity flow.

11. The method of claim 8 , wherein the positive or negative pressure source comprises a gas or liquid under positive or negative pressure.

12. The method of claim 8 , wherein the positive or negative pressure source comprises air under positive or negative pressure.

13. The method of claim 8 , further comprising recording a plurality of pressure measurements taken by the first pressure transducer during emptying or filling of the second liquid region, and regulating pressure delivered to the second control region ba

Assignees

• Deka Products Lp

Inventors

• Gray Larry B
• Bryant Jr Robert J

Classifications

• A61M2205/3331

  Pressure; Flow · CPC title

• F04B43/06 Primary

  Pumps having fluid drive · CPC title

• A61M5/16809

  by repeated filling and emptying of an intermediate volume (pressure infusion using positive displacement pumps A61M5/142) · CPC title

• F04B43/043

  Micropumps · CPC title

• A61M1/282

  Operational modes · CPC title