Device for electrochemical generation of gas

• US 5,593,552 A
• Filed: 03/30/1995
• Issued: 01/14/1997
• Est. Priority Date: 05/07/1993
• Status: Expired due to Fees

• Current Assignee: Microlin LLC
• Original Assignee: Ceramatec, Inc.
• Inventors: Joshi, Ashok V., Gordon, John H.
• Primary Examiner(s): Valentine, Donald R.
• Application Number:
  US08/413,635
• Time in Patent Office: 656 Days
• Field of Search: 204/228, 204/265, 204/266
• US Class Current: 204/230.5
• CPC Class Codes: A61M 2005/14204 with gas-producing electrochemical cell
• CPC Class Codes: B01J 19/2475 Membrane reactors
• CPC Class Codes: B01J 2219/00135 Electric resistance heaters
• CPC Class Codes: B01J 2219/00164 controlling the flow
• CPC Class Codes: B01J 2219/0018 controlling the conductivity
• CPC Class Codes: B01J 7/00 Apparatus for generating gases production of inert gas mixtures B01J19/14; for generating specific gases, see the relevant subclasses, e.g. C01B, C10J ; in "air bags" on vehicles B60R21/26; for starter gas F02C7/26; blasting cartridges for producing gas under pressure F42B3/04
• CPC Class Codes: B67D 7/0255 squeezing collapsible or flexible storage containers for dispensing beverages on draught B67D1/0462
• CPC Class Codes: F03G 7/005 Electro-chemical actuators; Actuators having a material for absorbing or desorbing gas, e.g. a metal hydride; Actuators using the difference in osmotic pressure between fluids; Actuators with elements stretchable when contacted with liquid rich in ions, with UV light, with a salt solution
• CPC Class Codes: F16N 11/10 by pressure of another fluid

Abstract

A device for generating controlled quantities of gas at predictable rates from an electrochemical cell containing a decomposable metal carbonate, bicarbonate or basic carbonate is disclosed. The cell provides more than one molecule of gas from the anode per 4 electrons passing through the cell circuit. The generated gas is comprised of carbon dioxide or a mixture of carbon dioxide and oxygen.

Claims

1. A device for electrochemically generating carbon dioxide gas or a mixture of carbon dioxide and oxygen gases in an adjustable quantity proportional to the cell current, comprising:

an electrochemical cell having a corrosion resistant container or housing;

a cathode chamber containing an electronically conductive current collector and adapted to contain a reducible material;

an anode chamber containing an electronically conductive current collector and adapted to contain an oxidizable material wherein said oxidizable material is a metal carbonate, metal bicarbonate, or combination thereof, and wherein the anode chamber structure has perforations or diffusion pores to permit gas to be released;

an ionically conductive separator between the anode chamber and cathode chamber structured to maintain physical separation of the materials in each chamber; and

optionally a switch and variable or fixed resistor forming a circuit with said power source and electrochemical cell.

2. The device of claim 1, wherein said anode and cathode are connected through an external circuit to a D.C. power supply.

3. The device of claim 2, wherein said external circuit contains a resistor.

4. The device of claim 3, wherein said resistor is a variable resistor.

5. The device of claim 2, wherein said external circuit contains a switch.

6. A device for dispensing fluids or semi-fluids where the rate of dispensing is proportional to the electrochemical generation of gas which in turn is proportional to a D.C. current passing through a gas-generating electrochemical cell, and where the gas generating cell utilized is the device claimed in claim 1, comprising:

two adjacent chambers which combined have fixed volume but which share a flexible diaphragm or movable member between them such that as the volume of one chamber increases, the volume of the second chamber decreases;

where gas generated from said electrochemical cell enters and pressurizes the first chamber;

where the second chamber is adapted to be filled with the fluid or semi-fluid to be dispensed; and

where the second chamber has an opening through which the fluid or semi-fluid will flow as gas enters the first chamber.

7. A device defined in claim 1 where the separator is a solid polymer electrolyte capable of selectively transporting monovalent metal cations.

8. A device defined in claim 1, wherein the separator is a cation conductive ceramic.

9. A device defined in claim 1 where the cathode includes a reducible metal salt.

10. A device defined in claim 1 where the cathode contains a halogen, chalcogen and mixtures thereof.

11. A device defined in claim 1 where the cathode is gas permeable and reduces oxygen.

12. A device defined in claim 1 where the cathode is gas permeable to evolved hydrogen.

13. A device defined in claim 12 where the oxygen absorber is adapted to release carbon dioxide as oxygen is absorbed so that the net gas stream from the anode is substantially carbon dioxide in larger volume than if only an oxygen absorber were utilized.

14. A device defined in claim 13 where the cathode includes as a constituent NiCO₃, CuCO₃ •

Cu(OH)₂ (malachite), or 2CUCO₃ •

Cu(OH)₂ (azurite).

15. A device defined in claim 1 additionally containing an oxygen absorber in communication with said anode chamber, said absorber adapted to absorb oxygen from the gas evolved from the anode so that the net gas stream from the anode is substantially carbon dioxide.

16. A device defined in claim 1 where the D.C. power source is a battery, capacitor, or solar cell, or combination thereof.

17. A device defined in claim 1 where the anodic current collector is nickel, nickel alloy, nickel oxide, or oxide of nickel alloy or nickel plated steel.

18. A device for electrochemically generating carbon dioxide gas or a mixture of carbon dioxide and oxygen gases in an adjustable quantity proportional to the cell current, comprising:

an electrochemical cell having a corrosion-resistant container or housing;

a cathode which includes as a constituent a reducible metal carbonate or basic carbonate and an electronically conductive current collector;

an anode with hydrophilic and hydrophobic zones with an electronically conductive current collector therebetween, and where the anode structure has perforations to permit gas to be released;

an ionically conductive, microporous, separator between the anode and cathode; and

a direct current (D.C) power source.

19. A substantially sealed device for electrochemically generating carbon dioxide gas or a mixture of carbon dioxide and oxygen gases in an adjustable quantity proportional to the cell current, comprising:

an electrochetnical cell having a corrosion resistant container or housing;

a sealed cathode chamber containing a reducible material and an electronically conductive current collector;

a substantially sealed anode chamber containing an oxidizable material and an electronically conductive current collector wherein said oxidizable material is a metal carbonate, metal bicarbonate, or combination thereof, and wherein the anode chamber structure has perforations or diffusion pores to permit gas to be released;

an ionically conductive separator between the anode chamber and cathode chamber structured to maintain physical separation of the materials in each chamber; and

optionally a switch and variable or fixed resistor forming a circuit with said power source and electrochemical cell.

20. A device as defined in claim 19, wherein the metal carbonate is a carbonate of a monovalent metal from the class consisting of sodium, lithium, potassium, rubidium, cesium, silver, and copper and mixtures thereof.

21. A device as defined in claim 19, wherein the metal bicarbonate is a carbonate of a monovalent metal selected from the class consisting of sodium, lithium, rubidium, potassium, cesium, silver, and copper and mixtures thereof.

22. A device defined in claim 21, wherein the solid polymer electrolyte is a laminated composite having a preference for the transport of cations.

23. A device defined in claim 22 where the ceramic is selected from the class consisting of beta-alumina or beta"-alumina ionic conductors in which cations such as sodium, lithium, potassium, rubidium, cesium, silver, or copper ions conduct under the influence of applied potential.

24. A device defined in claim 23 where the ceramic has the formula Na_1+x Zr_x P_3-x Si_x O₁₂ where x has a value of from zero to three.

25. A device defined in claim 22 where the ceramic is a metal ion super conductor electrolyte.

26. A device defined in claim 19 where the cathode includes a reducible metal salt selected from the class consisting of silver sulfate, copper sulfate, copper chloride and copper fluoride.

27. A device defined in claim 26 where the cathode contains iodine, sulfur and mixtures thereof.