Pyrotechnic air bag inflator with unitary filter

• US 5,547,638 A
• Filed: 07/26/1994
• Issued: 08/20/1996
• Est. Priority Date: 08/30/1993
• Status: Expired due to Fees

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Morton International Incorporated (Autoliv Incorporated)
• Inventors: Rink, Linda M., Hock, Christopher
• Primary Examiner(s): McMahon, Timothy M.
• Application Number:
  US08/280,485
• Time in Patent Office: 756 Days
• Field of Search: 422/164-167, 280/736, 280/740, 280/742
• US Class Current: 422/164
• CPC Class Codes: B01D 2273/20 High temperature filtration
• CPC Class Codes: B01D 2279/10 for air bags, e.g. inflators therefor
• CPC Class Codes: B01D 39/2051 Metallic foam
• CPC Class Codes: B01D 39/2093 Ceramic foam
• CPC Class Codes: B01D 46/24 Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
• CPC Class Codes: B01D 46/4218 Influencing the heat transfer which act passively, e.g. isolations, heat sinks, cooling ribs
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

A pyrotechnic air bag inflator utilizing non-azide gas generating material such as mixtures of copper oxide and amino tetrazol includes a unitary, rigid, drop-in type, filter for cooling and filtering high temperature, high pressure corrosive gas generated when the air bag inflator is activated to inflate an associated air bag. The filter comprises a reticulated structure formed of strong, porous, metal, metal alloy or ceramic material having a high thermal diffusivity and surface area for absorbing heat from the gas and defining a plurality of tortuous passages for entrapping contaminants from the gas passing through the filter.

Claims

1. An air bag inflator comprising:

a housing for containing gas generator means, said housing including a plurality of diffuser ports in an outer wall for directing gas to inflate an air bag; and

a unitary, filter element mounted in said housing for entrapping contaminants from generated gas moving from said gas generator means toward said diffuser ports;

said filter element including a rigid, porous body of ceramic foam, having a reticulated structure forming a plurality of tortuous paths for gas flow therethrough for entrapment of contaminants from said gas.

2. The air bag inflator of claim 1, wherein:

said reticulated structure is formed by chemical vapor deposition of a ceramic on a base of open-celled foam material.

3. The air bag inflator of claim 2, wherein:

said reticulated structure is sintered and said foam material is burned out.

4. The air bag inflator of claim 1, wherein:

said reticulated structure is coated with a metal alloy containing at least one element from the group consisting of;

aluminum, copper, iron, molybdenum, nickel, zirconium and tungsten.

5. The air bag inflator of claim 1, wherein:

said reticulated structure is coated with a ceramic material containing at least one of the materials from the group consisting of;

silicon carbide, silicon dioxide, alumina-silica, mullite and alumina.

6. The air bag inflator of claim 1, wherein:

said reticulated structure is formed of an open-celled foam material soaked in a ceramic mixture and sintered.

7. The air bag inflator of claim 1, wherein:

said porous body has a pores per square inch rating range of 20 to 65 PPI.

8. A filter for an air bag inflator comprising:

a unitary, filter element for entrapping contaminants from generated gas, said filter element including a rigid, porous body of ceramic foam, having a reticulated structure forming a plurality of tortuous paths for gas flow therethrough for entrapment of contaminants from said gas, said filter element being so dimensioned as to at least partially encompass a quantity of gas generating material.

9. The filter of claim 8, wherein:

said reticulated structure is formed by chemical vapor deposition of a ceramic on a base of open-celled foam material.

10. The filter of claim 9, wherein:

said reticulated structure is sintered and said foam material is burned out.

11. The filter of claim 8, wherein:

said reticulated structure is coated with a metal alloy containing at least one element from the group consisting of;

aluminum, copper, iron, molybdenum, nickel, zirconium and tungsten.

12. The filter of claim 8, wherein:

said reticulated structure is coated with a ceramic material containing at least one of the materials from the group consisting of;

silicon carbide, silicon dioxide, alumina-silica, mullite and alumina.

13. The filter of claim 8, wherein:

said reticulated structure os formed of an open-celled foam material soaked in a ceramic mixture an sintered.

14. The filter of claim 8, wherein:

said porous body has a pores per square inch rating range of 20 to 80 PPI.