Chemical oxygen generator

• US 5,198,147 A
• Filed: 04/10/1991
• Issued: 03/30/1993
• Est. Priority Date: 04/10/1991
• Status: Expired

• Current Assignee: BE Intellectual Property, Inc. (Rtx Corporation)
• Original Assignee: Puritan Bennett Corp. (Medtronic Plc)
• Inventors: Cannon, James C., Zhang, Yunchang
• Primary Examiner(s): Lovering, Richard D.
• Assistant Examiner(s): ANTHONY, JOSEPH DAVID
• Application Number:
  US07/683,276
• Time in Patent Office: 720 Days
• Field of Search: 252/187.31, 252/187.1
• US Class Current: 252/187.31
• CPC Class Codes: A62B 21/00 Devices for producing oxygen from chemical substances for respiratory apparatus
• CPC Class Codes: C01B 13/0218 Chlorate
• CPC Class Codes: C01B 13/0296 Generators releasing in a self-sustaining way pure oxygen from a solid charge, without interaction of it with a fluid nor external heating, e.g. chlorate candles or canisters containing them charges per se C01B13/02

Abstract

An improved chemical oxygen generator (10) includes an oxygen generating candle (12) having an oxygen source, which upon decomposition will yield oxygen, and a nontoxic additive to smooth decomposition and suppress formation of toxic free chlorine gas. The nontoxic additive may be taken from the group consisting of: (1) the oxides, hydroxides and carbonates of calcium and the rare earth elements; (2) the hydroxides and carbonates of magnesium; and (3) mixtures of the foregoing. A complete chemical oxygen generator utilizes the candle (12) of the invention. The oxygen generator preferably includes a canister (14), oxygen-generating candle (12), and an ignition device (16). Triggering of the ignition device ignites an ignition pellet (52) which initiates decomposition of the candle body (50). Once initiated, the candle will sustain decomposition to release breathable oxygen until the candle is completely reacted.

Claims

1. In an oxygen-generating candle for producing a breathable gas and including therein an amount of an oxygen source which upon ignition and decomposition thereof will yield oxygen and residual chlorine, the improvement which comprises from about 0.5-15% by weight of a metal powder fuel, from about 20-99% by weight of an oxygen source selected from the group consisting of sodium chlorate, potassium chlorate, lithium chlorate, sodium perchlorate, potassium perchlorate and lithium perchlorate and from about 0.05-10% by weight of a nontoxic additive incorporated into said candle for suppression of said residual chlorine and smoothing the decomposition of said candle, said additive being selected from the group consisting of:

(1) the oxides, hydroxides and carbonates of calcium and the rare earth elements;

(2) the hydroxides and carbonates of magnesium; and

(3) mixtures of the foregoing, said additive being in intimate admixture with said fuel and oxygen source for suppressing the formation of free chlorine and smoothing the decomposition of said candle upon said ignition thereof, said candle being operable for producing said breathable gas over a period of several minutes.

2. The oxygen-generating candle of claim 1, said additive comprising calcium hydroxide.

3. The oxygen-generating candle of claim 1, said additive comprising from about 0.05 to 10% by weight of calcium hydroxide.

4. The oxygen-generating candle of claim 3, said calcium hydroxide being present at a level of from about 0.2 to 2.0% by weight.

5. The oxygen-generating candle of claim 1, said oxygen source being sodium chlorate.

6. The oxygen-generating candle of claim 1, said oxygen source being potassium perchlorate.

7. The oxygen-generating candle of claim 1, further including a catalyst, and a binder.

8. The oxygen-generating candle of claim 7, said catalyst comprising a cobalt oxide.

9. The oxygen-generating candle of claim 7, said binder selected from the group consisting of glass powder, glass fiber, ceramic fiber, steel wool, and mixtures thereof.

10. The oxygen-generating candle of claim 8, said cobalt oxide selected from the group consisting of CoO, Co₃ O₄, Co₂ O₃, and CoO_x wherein x ranges from about 1.0 to 1.5, and mixtures thereof.

11. The oxygen-generating candle of claim 1, said metal powder fuel being selected from the group consisting of iron, manganese, cobalt, nickel, tungsten, titanium, magnesium, aluminum, niobium, zirconium and mixtures thereof.

12. The oxygen-generating candle of claim 11, said metal powder fuel being iron powder having high purity and high surface area.

13. The oxygen-generating candle of claim 1, said candle further including ignition means, wherein said candle is further comprised of a first composition layer in contact with said ignition means and at least one additional composition layer, said additive being incorporated into said additional layer.