Pyrotechnic igniter with radio frequency filter

• US 6,357,355 B1
• Filed: 02/10/2000
• Issued: 03/19/2002
• Est. Priority Date: 02/10/2000
• Status: Expired due to Fees

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Fogle, Homer W. Jr.
• Primary Examiner(s): Carone, Michael J.
• Assistant Examiner(s): Semunegus, Lulit
• Application Number:
  US09/501,946
• Time in Patent Office: 768 Days
• Field of Search: 102/202.2, 102/202.4, 102/202.7, 102/202.9
• US Class Current: 102/202.2
• CPC Class Codes: F42B 3/188 having radio-frequency filters , e.g. containing ferrite cores or inductances F42B3/185 takes precedence

Abstract

A pyrotechnic device comprises a body of ignitable material (66). A pair of electrodes (44) and (52) provide electrical energy to heat and ignite the body of pyrotechnic material (66). The electrodes (44) and (52) extend through an electrical insulation housing (78). The electrical insulation housing (78) has surfaces defining a chamber (92) through which the electrodes (44) and (52) pass. A body (94) of a solid electromagnetically lossy, substantially gas impermeable material is positioned within the chamber (92). The lossy material comprises a vitreous ceramic matrix consisting essentially of about 5% to about 50% by weight of a multi-component glass binder and about 50% to about 95% by weight of an electromagnetically lossy ferromagnetic and/or ferroelectric filler. The body (94) of lossy material is fused to the surfaces defining the chamber (92) in the electrical insulation housing (78) and to the electrodes (44) and (52).

Claims

1. A pyrotechnic device comprising:

a body of ignitable pyrotechnic material;

a pair of electrodes for providing electrical energy to heat and ignite the body of pyrotechnic material;

an electrical insulation housing through which the electrodes extend, the electrical insulation housing comprising a molded thermoplastic and having surfaces defining a chamber through which the electrodes pass;

a body of a solid electromagnetically lossy substantially gas impermeable material in the chamber, the lossy material comprising a vitreous ceramic matrix consisting essentially of (a) about 5-50% by weight of a multi-component glass binder and (b) about 50-95% by weight of a electromagnetically lossy ferromagnetic and/or ferroelectric filler interspersed throughout;

the body of lossy material forming a gas-tight seal with the surfaces defining the chamber and the electrodes.

2. The pyrotechnic igniter of claim 1, wherein the binder is lead borosilicate glass.

3. The pyrotechnic igniter of claim 1, wherein the binder is lead aluminoborosilicate glass.

4. The pyrotechnic igniter of claim 1, wherein the lossy ferromagnetic filler comprises a spinal ferrite having the general formula (AaO)₁₋

x(BbO)_xFe₂O₃ where Aa and Bb are divalent metal cations of Ba, Cd, Co, Cu, Fe, Mg, Mn, Ni, Sr, or Zn, and x is a fractional number in the semi-open interval [0,1).

5. The pyrotechnic igniter of claim 1, wherein the lossy ferroelectric filler is selected from the group consisting of perovskite titanates having the general formula (XxO)TiO₂ and perovskite zirconates having the general formula (XxO)ZrO₂ where Xx denotes divalent metal cations of Ba, La, Sr, or Pb.

6. The pyrotechnic igniter of claim 1, wherein the lossy ferroelectric filler comprises a La-modified lead zirconium titanate perovskite ceramic.

7. A method of making a pyrotechnic igniter comprising the following steps:

providing a body of a solid electromagnetically lossy substantially gas impermeable material, the lossy material comprising a vitreous ceramic matrix consisting essentially of (a) about 5-50% by weight of a multi-component glass binder and (b) about 50-95% by weight of a electromagnetically lossy ferromagnetic and/or ferroelectric filler interspersed throughout;

extending a pair of electrodes through the body of lossy material, the electrodes providing electrical energy to heat and ignite a body of pyrotechnic material;

forming a gas-tight seal with the body of lossy material and the electrodes;

molding a thermoplastic material around the body of lossy material, a gas-tight seal being formed between the molded thermoplastic material and the body of lossy material; and

positioning the body of pyrotechnic material in heat transferring relationship with the electrodes.

8. A pyrotechnic device comprising:

a body of ignitable pyrotechnic material;

a pair of electrodes for providing electrical energy to heat and ignite the body of pyrotechnic material;

an electrical insulation housing through which the electrodes extend, the electrical insulation housing comprising a molded thermoplastic and having a sidewall with a cylindrical surface defining a chamber through which the electrodes pass;

a body of a solid electromagnetically lossy substantially gas impermeable material in the chamber, the lossy material comprising a vitreous ceramic matrix consisting essentially of (a) about 5-50% by weight of a multi-component glass binder and (b) about 50-95% by weight of a electromagnetically lossy ferromagnetic and/or ferroelectric filler interspersed throughout; and

the body of lossy material forming a gas-tight seal with the cylindrical surface defining the chamber in the electrical insulation housing and the electrodes.