Vertical type porous membrane hydrogen generator

• US 4,261,955 A
• Filed: 09/01/1978
• Issued: 04/14/1981
• Est. Priority Date: 09/01/1978
• Status: Expired due to Term

• Current Assignee: The United States Of America As Represented By The Secretary Of The Army
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Bailey, Cornelius E. Jr., Taschek, Walter G.
• Primary Examiner(s): Scovronek, Joseph
• Application Number:
  US05/939,028
• Time in Patent Office: 956 Days
• Field of Search: 422/239, 422/238, 422/117, 422/129, 422/305, 422/120, 422/236, 429/17, 429/19, 423/657, 48/61, 48/4 (U.S. only)
• US Class Current: 422/239
• CPC Class Codes: B01J 7/02 by wet methods
• CPC Class Codes: C01B 13/0207 Water
• CPC Class Codes: C01B 3/065 from a hydride
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis

Abstract

The disclosure concerns an apparatus for generating gas by the reaction of water reactive gas producing fuel with water vapor. A chamber houses the metal hydride fuel and a water vapor is introduced into the fuel chamber through a pair of spaced porous hydrophobic membranes. Reaction of the water vapor with the fuel produces a gas such as hydrogen (if calcium hydride fuel is used) or oxygen for use in a fuel cell. A "dead space" is positioned between the porous hydrophobic membranes which provides a safety feature that is unique in its use. If, during operation, an excessive sudden demand is made for the generated gas, i.e. hydrogen, and in turn for water vapor, with this invention, unvaporized water which might be pulled through the outer membrane or membranes will then pass through the hydrogen outlet rather than accidently directly contacting the fuel.

Claims

1. A demand responsive gas generator for producing gas by chemical reaction of a solid fuel upon controlled exposure to a liquid vapor, said generator comprising:

(1) a fuel compartment for storing solid fuel;

(b) a separate liquid compartment adjacently spaced apart from said fuel compartment and having means to receive liquid water supplied thereto under a suitable pressure from an external reservoir in a controlled manner;

(c) wall means between said fuel and water compartments to maintain said compartments in spaced apart relation;

(d) said wall means comprising at least one pair of spaced apart porous hydrophobic membranes adapted to pass gaseous and vaporous mediums while simultaneously adapted to restrict free passage of liquid water under normal demand operation, said membranes designated as a first membrane closest to and forming part of said liquid compartment, and a second membrane closest to and forming part of said fuel compartment;

(e) spacer means for maintaining said membranes in spaced apart relation so as to form a gas passageway therebetween; and

(f) outlet means connected with said gas passageway for conducting produced gas away from the generator to an external gas utilization means, and for also conducting away any excess liquid water collecting therein,

(g) whereby an abnormal demand for gas utilization may cause a substantial sudden decrease in gas pressure in the gas passageway tending to cause liquid water to pass through said first membrane, and which liquid water is also directable away from said generator through said outlet means before it can permeate the second membrane into said fuel compartment.

2. The gas generator as defined in claim 1, wherein said membranes are formed of porous Teflon sheet material.

3. In a demand responsive hydrogen generator for producing hydrogen gas by chemical reaction of a solid fuel upon controlled exposure to a water vapor, wherein the generator includes a separate solid fuel compartment and liquid compartment means to receive controlled amounts of liquid water, and further includes a gas discharge outlet, wall means separating said fuel and liquid compartments, with the wall means having a hydrophobic porous membrane area adapted to pass gaseous and vaporous mediums while also restricting free passage of liquid water therethrough, the improvement wherein

(a) said wall means comprises a pair of spaced apart hydrophobic membranes;

and

(b) said generator further includes suitable spacer means for maintaining said membranes in spaced-apart relation to form a gas passageway therebetween, said spacers being of a character so as to permit gas produced in said fuel compartment to freely pass by said spacer means enroute to said gas discharge outlet.

4. The gas generator as defined in claim 3, wherein said fuel compartment is bounded on two sides with said water compartment means and with interposed wall means comprising said spaced apart hydrophobic membranes to provide increased gas generation capabilities, said wall means being interposed between said fuel compartment and liquid water introducable into said water compartment means.

5. The gas generator as defined in claim 3, wherein said fuel compartment is bounded on a major part of its periphery with said water compartment means and said fuel compartment being separated along said major part of its periphery from the aforesaid water compartment means by said wall means comprising said spaced apart hydrophobic membranes.