Methods for controlling a pump's flow rate by pulsed discharge

• US 6,749,403 B2
• Filed: 05/20/2003
• Issued: 06/15/2004
• Est. Priority Date: 07/20/1999
• Status: Expired due to Term

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Bryant, Robert J., Spencer, Geoff P., Gray, Lawrence B.
• Primary Examiner(s): Yu, Justine R.
• Assistant Examiner(s): Solak, Timothy P.
• Application Number:
  US10/441,462
• Publication Number:
  US 20030194328A1
• Time in Patent Office: 392 Days
• Field of Search: 417/53, 417/392, 417/395, 417/214, 417/297, 417/302, 417/413.1, 417/521
• US Class Current: 417/53
• CPC Class Codes: A61M 1/36225 with blood pumping means or components thereof
• CPC Class Codes: A61M 1/362261 at least one cassette surface or portion thereof being flexible, e.g. the cassette having a rigid base portion with preformed channels and being covered with a foil
• CPC Class Codes: A61M 1/362264 the filter being a blood filter
• CPC Class Codes: A61M 1/362265 Details of valves
• CPC Class Codes: A61M 1/362266 Means for adding solutions or substances to the blood
• CPC Class Codes: A61M 1/367 Circuit parts not covered by the preceding subgroups of group A61M1/3621
• CPC Class Codes: A61M 1/3696 with means for adding or withdrawing liquid substances during the centrifugation, e.g. continuous centrifugation
• CPC Class Codes: A61M 2205/053 ultraviolet
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2205/123 with incorporated reservoirs
• CPC Class Codes: A61M 2205/125 with incorporated filters
• CPC Class Codes: A61M 2205/128 with incorporated valves
• CPC Class Codes: A61M 2205/14 Detection of the presence or absence of a tube, a connector or a container in an apparatus
• CPC Class Codes: A61M 2205/17 with redundant control systems
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3396 Reservoirs being alternately filled and emptied for measuring flow rate or delivered volume
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 39/22 Valves or arrangement of valves A61M39/02, A61M39/0247, A61M39/16 take precedence; regulating valves in infusion systems A61M5/16881; in devices worn by the patient for the reception of urine, faeces, catamenial or other discharge, or in colostomy devices A61F5/4405
• CPC Class Codes: A61M 39/281 Automatic tube cut-off devices, e.g. squeezing tube on detection of air
• CPC Class Codes: A61M 5/14224 Diaphragm type
• CPC Class Codes: A61M 5/14593 : the diaphragm being actuated by fluid pressure
• CPC Class Codes: A61M 5/16809 : by repeated filling and emptying of an intermediate volume pressure infusion using positive displacement pumps A61M5/142
• CPC Class Codes: A61M 5/16813 : by controlling the degree of opening of the flow line
• CPC Class Codes: A61M 5/16859 : Evaluation of pressure response, e.g. to an applied pulse
• CPC Class Codes: A61M 5/365 : Air detectors A61M5/1684 takes precedence; in extracorporeal blood circuits A61M1/3626
• CPC Class Codes: A61M 60/109 : incorporated within extracorporeal blood circuits or systems
• CPC Class Codes: A61M 60/113 : in other functional devices, e.g. dialysers or heart-lung machines
• CPC Class Codes: A61M 60/43 : using vacuum at the blood pump, e.g. to accelerate filling
• CPC Class Codes: A61M 60/546 : of blood flow, e.g. by adapting rotor speed
• CPC Class Codes: A61M 60/847 : arranged in a cassette
• CPC Class Codes: A61M 60/851 : Valves
• CPC Class Codes: A61M 60/892 : Active valves, i.e. actuated by an external force
• CPC Class Codes: A61M 60/894 : Passive valves, i.e. valves actuated by the blood
• CPC Class Codes: F04B 13/00 : Pumps specially modified to deliver fixed or variable measured quantities
• CPC Class Codes: F04B 43/0081 : systems, control, safety measures
• CPC Class Codes: F04B 43/067 : the fluid being actuated directly by a piston
• CPC Class Codes: F04B 43/073 : the actuating fluid being controlled by at least one valve
• CPC Class Codes: F04B 43/107 : the fluid being actuated directly by a piston
• CPC Class Codes: F04B 43/113 : the actuating fluid being controlled by at least one valve
• CPC Class Codes: F04B 49/065 : and making use of computers
• CPC Class Codes: F04B 49/24 : Bypassing
• CPC Class Codes: F04B 53/06 : Venting

Abstract

Methods and systems are disclosed for pumping fluids at desired average flow rates by applying a predetermined force to a pump chamber and pulsing an outlet valve of the pump chamber to deliver a fluid therefrom. In some embodiments, pump chambers are provided within removable pumping cartridges that are constructed and configured to be coupled to a reusable pump drive component. In other embodiments, the pumping cartridges include multiple pump chambers, which pump chambers are operated so that a pump flow rate of one pump chamber is a predetermined fraction of the pump flow rate of another pump chamber within the pumping cartridge.

Claims

1. A method for pumping a liquid at a desired average flow rate with a pumping cartridge, the cartridge including at least one pump chamber, at least a portion of which pump chamber includes a movable surface, the method comprising the steps of:

a. at least partially filling said pump chamber with a liquid;

b. isolating said pump chamber;

c. applying a force to said movable surface;

d. regulating the flow of liquid from the pump chamber while maintaining said force on the surface.

2. The method of claim 1, wherein said movable surface comprises a flexible membrane.

3. The method of claim 2, further comprising a step of coupling the pumping cartridge to a reusable component so that the membrane, upon coupling to the reusable component, forms a fluid-tight seal between the pump chamber and a depression within a portion of the reusable component in contact with the pumping cartridge, which depression forms a control chamber in contact with and adjacent to the pump chamber.

4. The method of claim 3, wherein said control chamber is in fluid communication with a fluid supply system included in the reusable component, which fluid supply system is constructed and arranged to pressurize the control chamber thereby applying a force to the membrane.

5. The method of claim 1, wherein said movable surface comprises an elastic membrane.

6. The method of claim 1, wherein step (d) comprises pulsing a valve.

7. The method of claim 6, wherein step (a) comprises a step of closing a valve positioned on an outlet line of the pump chamber and applying a force to the movable surface such that an internal volume of the pump chamber is increased.

8. The method of claim 7, wherein step (b) comprises a step of closing a valve positioned on an inlet line of the pump chamber.

9. The method of claim 8, wherein step (c) comprises a step of maintaining the valve on the inlet line of the pump chamber in a closed position and applying a fluid having a positive pressure in contact with the movable surface, said fluid creating a force on said surface tending to decrease an internal volume of the pump chamber.

10. The method of claim 9, wherein step (d) comprises maintaining the valve on the inlet line of the pump chamber in a closed position and opening the outlet valve for selected time periods at selected intervals while continuously applying a positive pressure in contact with the movable surface;

said selected time periods and intervals being chosen to yield at least one of a desired volume of liquid delivered and a desired average liquid flow rate.

11. The method of claim 10, wherein the positive pressure applied in contact with the movable surface is adjusted and controlled to yield a desired volume of liquid delivered and a desired average liquid flow rate to a pumping destination, where a pressure at said pumping destination varies during pumping of the liquid to the destination.

12. The method of claim 1, further comprising after step (b) the step of determining a first measured parameter related to a volume of the pump chamber.

13. The method of claim 12, further comprising after step (d) the steps of isolating the pump chamber and determining a second measured parameter related to a second volume of the pump chamber.

14. The method of claim 13, further comprising the step of determining at least one of a volume of liquid delivered and an average liquid flow rate at least in part from the first and second measured parameters.

15. A method for pumping at least one liquid utilizing a pumping cartridge including at least a first pump chamber and a second pump chamber comprising:

operating the first pump chamber at conditions selected to yield a first flow rate of liquid delivered from or to the first pump chamber;

operating the second pump chamber according to the method of claim 1 to yield a second average flow rate of liquid from the second pump chamber, said second average flow rate being a selected fraction of said first flow rate.

16. The method of claim 15, wherein the first pump chamber and the second pump chamber are operated simultaneously.

17. The method of claim 15, wherein the first pump chamber delivers a first liquid and the second pump chamber delivers a second liquid, said first liquid and said second liquid being different in composition.

18. The method of claim 15, wherein the first pump chamber delivers liquid to a first downstream destination and the second pump chamber delivers liquid to a second downstream destination different from said first downstream destination.

19. A method for pumping a liquid at a desired average flow rate with a pumping cartridge including at least one pump chamber, at least a portion of which pump chamber comprises a movable surface, comprising:

a. closing a valve positioned on an outlet line of said pump chamber;

b. at least partially filling said pump chamber with a liquid;

c. closing a valve positioned on an inlet line of said pump chamber, thereby isolating said pump chamber; and

, while maintaining said inlet valve in a closed position,

d. applying a force to said movable surface; and

e. opening the outlet valve for selected time periods at selected intervals while maintaining the force on the movable surface, said selected time periods and intervals being chosen to yield a desired average flow rate.

20. A method as in claim 19, wherein said movable surface comprises a flexible membrane.

21. A method as in claim 19, wherein said movable surface comprises an elastic membrane.