ACCURATE FLOW CONTROL IN DRUG PUMP DEVICES

• US 20130178826A1
• Filed: 11/19/2012
• Published: 07/11/2013
• Est. Priority Date: 11/18/2011
• Status: Abandoned Application

• Current Assignee: MiniPumps, LLC
• Original Assignee: MiniPumps, LLC
• Inventors: LI, PO-YING
• Application Number:
  US13/680,869
• Publication Number:
  US 20130178826A1
• Time in Patent Office: Days
• US Class Current: 604/506
• CPC Class Codes: A61M 2005/14252 with needle insertion means
• CPC Class Codes: A61M 2039/1072 with a septum present in the connector
• 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 5/14248 of the skin patch type
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/155 pressurised by gas introduced into the reservoir
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence

Abstract

The accuracy of drug delivery with drug pump devices may be improved by a combination of pump operation at high flow resistances and pump pressures, pressure-relief mechanisms, and sensor-based feedback for pump control.

Claims

1. A pump device comprising:

an electrolysis pump comprising

a pump chamber and contained therein a pair of electrodes in contact with a liquid electrolyte for generating an electrolysis gas from the electrolyte upon application of a voltage between the electrodes; and

a pressure-relief mechanism for causing recombination of the electrolysis gas into the liquid electrolyte.

2. The device of claim 1, wherein the pressure-relief mechanism comprises a spark-ignition circuit including a spark gap disposed within the pump chamber, generation of a spark at the spark gap causing the recombination of at least a portion of the electrolysis gas.

3. The device of claim 2, wherein the spark-ignition circuit is configured to facilitate interrupting the spark before recombination of the electrolysis gas is complete.

4. The device of claim 2, wherein the pump chamber comprises first and second compartments and a gas-permeable separation therebetween, the spark plug being disposed in the first compartment to thereby limit the recombination of the electrolysis gas to the first compartment.

5. The device of claim 4, wherein the separation comprises at least one of a membrane, a porous material, a solid wall with holes, or a valve.

6. The device of claim 1, wherein the pressure-relief mechanism comprises an electrically conductive filament disposed within the pump chamber, heating of the filament upon application of a current thereto causing the recombination of the electrolysis gas.

7. The device of claim 1, wherein the pressure-relief mechanism comprises a catalyst that continuously causes recombination of electrolysis gas.

8. The device of claim 7, wherein the catalyst comprises a material selected from the group consisting of platinum, palladium, nickel, iridium, or nickel-cadmium.

9. The device of claim 7, wherein the catalyst comprises a nano-catalytic material.

10. The device of claim 9, wherein the nano-catalytic material comprises at least one of a nano-porous material, nanowires, or nanoparticles.

11. The device of claim 7, wherein the catalyst causes recombination of at least 99% by volume of the electrolysis gas within no more than two minutes upon cessation of the application of a voltage between the electrodes.

12. The device of claim 1, wherein the pressure-relief mechanism comprises an active pressure-relief valve fluidically connecting an interior of the pump chamber with an exterior of the pump chamber.

13. The device of claim 12, wherein the valve comprises at least one of a solenoid valve, a diaphragm valve, a ball valve, or a duckbill valve.

14. The device of claim 12, wherein the liquid electrolyte is absorbed within a hydrophilic material in contact with the electrodes to thereby prevent release of the liquid electrolyte through the valve.

15. The device of claim 1, wherein the pressure-relief mechanism comprises a gas-permeable, liquid-impermeable material forming a portion of an enclosure of the pump chamber.

16. The device of claim 15, wherein the gas-permeable, liquid-impermeable material comprises at least one of porous Teflon, porous sol-gel ceramic, or a sintered porous metal.

17. The device of claim 16, wherein the enclosure portion formed of the gas-permeable, liquid-impermeable material has at least one of a size or porosity corresponding to a predetermined permeability rate at an operating pressure.

18. The device of claim 1, further comprising a control mechanism for variably controlling the pressure-relief mechanism.

19. The device of claim 1, further comprising:

a drug reservoir in mechanical communication with the pump chamber via an intervening displacement member; and

an exit member for fluidically connecting the reservoir with a drug injection site,

whereby gas generated in the pump chamber exerts a pressure to drive the displacement member toward the exit member and thereby force therethrough fluid in the drug reservoir.

20. The device of claim 19, further comprising:

a flow sensor for measuring a flow rate of fluid flow through the exit member; and

a control circuit for (i) integrating the flow rate to determine a dosage of fluid and (ii) upon reaching a specified dosage, interrupting application of the voltage between the electrodes.

21. The device of claim 19, wherein the control circuit is further configured to trigger the pressure-relief mechanism upon reaching the specified dosage.

22. The device of claim 19, wherein the control circuit is further configured to variably control the pressure-release mechanism to facilitate partial pressure relief.

23. A drug pump device comprising:

a drug reservoir;

an exit member for fluidically connecting the reservoir with a drug injection site;

an electrolysis pump comprising

(i) a pump chamber in mechanical communication with the drug reservoir via an intervening displacement member, the pump chamber containing a pair of electrodes in contact with a liquid electrolyte for generating an electrolysis gas from the electrolyte upon application of a voltage between the electrodes, gas generated in the pump chamber exerting a pressure to drive the displacement member toward the exit member and thereby force therethrough fluid in the drug reservoir, and

(ii) a pressure-relief mechanism for causing recombination of the electrolysis gas into the liquid electrolyte;

a flow sensor for measuring fluid flow through the exit member; and

a control circuit for integrating the flow rate to determine a dosage of fluid and, upon reaching a specified dosage, interrupting application of the voltage between the electrodes.

24. The device of claim 23, wherein the pressure-relief mechanism is controllable and the control circuit is configured to trigger the pressure-relief mechanism upon reaching the specified dosage.

25. The device of claim 23, wherein the pressure-relief mechanism is continuous.

26. In a drug pump device comprising a drug reservoir, an exit member for fluidically connecting the reservoir with a drug injection site, an electrolysis pump operable to generate electrolysis gas exerting a pressure on the reservoir to thereby force fluid from the reservoir into the exit member, a flow sensor disposed within the exit member, and a pressure-relief mechanism for causing recombination of the electrolysis gas, a method of controlling a dosage of fluid delivered to the injection site, the method comprising:

using the flow sensor, measuring fluid flow through the exit member;

integrating the flow rate to determine a dosage of fluid and, upon reaching a specified dosage, interrupting generation of the electrolysis gas.

27. The device of claim 26, further comprising, upon reaching the specified dosage, triggering the pressure-relief mechanism.