Gas generator for inflatable life raft

• US 4,066,415 A
• Filed: 02/02/1976
• Issued: 01/03/1978
• Est. Priority Date: 02/03/1975
• Status: Expired due to Term

• Current Assignee: Nippon Oil and Fats Co., Ltd.
• Original Assignee: Nippon Oil and Fats Co., Ltd.
• Inventors: Wada, Makoto, Tsuji, Shinzo, Kasama, Tsuneo, Sano, Masakatu
• Primary Examiner(s): Scovronek, Joseph
• Application Number:
  US05/654,347
• Time in Patent Office: 701 Days
• Field of Search: 23/281, 280/741, 149/35, 9/11 A, 9/321, 9/322, 9/324, 431/267, 431/273, 431/274, 431/275, 102/39
• US Class Current: 422/165
• 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: B63C 9/18 Inflatable equipment characterised by the gas-generating or inflation device

Abstract

A gas generator for an inflatable life raft having a gas-generating chamber filled with a gas-generating composition which generates gas by chemical reaction, either a chemical cooling chamber or a physical cooling-and-filtering chamber or both, a gas passage in communication with a safety valve, and an ignition device which provides rotational friction between a friction means and a frictional igniting agent. The gas generator has the advantages that it is not influenced by the environmental temperature, a gas temperature drop due to adiabatic gas expansion accompanying the gas discharge does not occur and therefore the generated gas can very reliably be discharged, the gas is fully cleaned, troubles due to abnormality of the gas-generating composition can be avoided, and it can be made light and small.

Claims

1. A gas generator for inflating inflatable objects, comprising:

an elongated casing having a gas outlet at one longitudinal end thereof and adapted to be connected to an inflatable object, means in said casing defining an elongated central gas-generating chamber containing a gas-generating composition which generates gas by combustion or thermal decomposition and an igniter for igniting said gas-generating composition, means in said casing defining an elongated annular second chamber encircling said gas-generating chamber and connected in series gas flow relationship between said gas-generating chamber and said gas outlet, said second chamber being in radial gas flow communication with said gas-generating chamber and containing either a bed of an endothermically decomposable substance adapted to chemically cool the gas generated in said gas-generating chamber or a bed of a solid physically cooling and filtering substance for physically cooling and filtering said gas or serially arranged beds of both of said substances, said casing having means defining an elongated annular gas flow passage surrounding said second chamber and connected in series gas flow relationship between said second chamber and said gas outlet, and pressure relief valve means mounted on said casing and connected in said gas flow passage and adapted to be opened to place the gas flow passage in communication with the ambient atmosphere when the pressure of the cooled gas flowing through said gas flow passage into said gas outlet exceeds a predetermined value, said gas outlet being a converging nozzle mounted on said casing adjacent one axial end of said gas flow passage.

2. A gas generator as claimed in claim 1 wherein the second chamber contains physical cooling and filtering substance selected from the group consisting of silica, alumina, silica-alumina, glass wool, metallic wool and wire gauze.

3. A gas generator as claimed in claim 1 wherein the second chamber contains endothermically decomposable substance selected from the group consisting of zinc carbonate, calcium carbonate, magnesium carbonate, sodium carbonate, calcium bicarbonate and sodium bicarbonate.

4. A gas generator as claimed in claim 1 in which said gas-generating composition consists essentially of a mixture of sodium azide and manganese oxide (IV).

5. A gas generator as claimed in claim 1 wherein said substance in said second chamber is confined between and is supported by wire gauze layers.

6. A gas generator as claimed in claim 1 wherein said second chamber contains a bed of said endothermically decomposable substance and a bed of said physical cooling and filtering substance arranged in series between said gas-generating chamber and said gas flow passage.

7. A gas generator as claimed in claim 6 in which said endothermically decomposable substance is selected from the group consisting of zinc carbonate, calcium carbonate, magnesium carbonate, sodium carbonate, calcium bicarbonate and sodium bicarbonate and said physical cooling and filtering substance is selected from the group consisting of silica, alumina, silica-alumina, glass wool, metallic wool and wire gauze.

8. A gas generator as claimed in claim 1 wherein said gas-generating composition consists essentially of 60 parts by weight of sodium azide and 40 parts by weight of manganese oxide (IV).

9. A gas generator for inflating inflatable objects, comprising:

a casing having a gas outlet adapted to be connected to an inflatable object, means in said casing defining a gas-generating chamber containing a gas-generating composition which generates gas by combustion or thermal decomposition and an igniter for igniting said gas-generating composition, said igniter comprising a rotary body mounted on a rotatable shaft and having friction means on its surface, means for rotating said shaft, a frictional ignition agent associated with said gas-generating composition and being positioned to contact said friction means and having a recessed portion for accommodating said friction means so that said friction means does not contact said frictional ignition agent until said friction means is rotated, means in said casing defining a second chamber connected in series between said gas-generating chamber and said gas outlet, said second chamber being in gas flow communication with said gas-generating chamber and containing either a bed of an endothermically decomposable substance adapted to chemically cool the gas generated in said gas-generating chamber or a bed of a solid physical cooling and filtering substance for physically cooling and filtering said gas or serially arranged beds of both of said substances, said casing having means defining a gas flow passage connected in series between said second chamber and said gas outlet.

10. A gas generator for inflating inflatable objects, comprising:

an elongated casing having a gas outlet at one longitudinal end thereof and adapted to be connected to an inflatable object, means in said casing defining an outer elongated annular gas-generating chamber containing a gas-generating composition which generates gas by combustion or thermal decomposition and an igniter for igniting said gas-generating composition, means in said casing defining an inner elongated annular second chamber disposed within and encircled by said gas-generating chamber and connected in series gas flow relationship between said gas-generating chamber and said gas outlet, said second chamber being in radial gas flow communication with said gas-generating chamber and containing either a bed of an endothermically decomposable substance adapted to chemically cool the gas generated in said gas-generating chamber or a bed of a solid physical cooling and filtering substance for physically cooling and filtering said gas or serially arranged beds of both of said substances, the central opening of said second chamber defining an elongated gas flow passage connected in series between said second chamber and said gas outlet, and pressure relief valve means mounted on said casing at the opposite end thereof from said gas outlet and connected in said gas flow passage and adapted to be opened to place the gas flow passage in communication with the ambient atmosphere when the pressure of the cooled gas flowing through said gas flow passage into said gas outlet exceeds a predetermined value.

11. A gas generator as claimed in claim 10 wherein the second chamber contains physical cooling and filtering substance selected from the group consisting of silica, alumina, silica-alumina, glass wool, metallic wool and wire gauze.

12. A gas generator as claimed in claim 10 wherein the second chamber contains endothermically decomposable substance selected from the group consisting of zinc carbonate, calcium carbonate, magnesium carbonate, sodium carbonate, calcium bicarbonate and sodium bicarbonate.

13. A gas generator as claimed in claim 10 in which said gas-generating composition consists essentially of a mixture of sodium azide and manganese oxide (IV).

14. A gas generator as claimed in claim 10 wherein said substance in said second chamber is confined between and is supported by wire gauze layers.

15. A gas generator as claimed in claim 10 wherein said second chamber contains a bed of said endothermically decomposable substance and a bed of said physical cooling and filtering substance arranged in series between said gas-generating chamber and said gas flow passage.

16. A gas generator as claimed in claim 15 in which said endothermically decomposable substance is selected from the group consisting of zinc carbonate, calcium carbonate, magnesium carbonate, sodium carbonate, calcium bicarbonate and sodium bicarbonate and said physical cooling and filtering substance is selected from the group consisting of silica, alumina, silica-alumina, glass wool, metallic wool and wire gauze.

17. A gas generator as claimed in claim 10 wherein said gas-generating composition consists essentially of 60 parts by weight of sodium azide and 40 parts by weight of manganese oxide (IV).