Method and composition for generating nitrogen gas
First Claim
1. A solid composition for generating nitrogen gas substantially free of noxious and toxic impurities, comprising essentially a mixture of alkali metal azide and at least a stoichiometric amount of a metal oxide selected from the group consisting of iron, titanium and copper oxides aNd mixtures thereof, said metal oxide being capable of reacting exothermically with the alkali metal azide and wherein the metal of the oxide is lower in the electromotive series than the alkali metal of the azide and is a metal other than the alkali.
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Abstract
A gas generating composition is disclosed wherein the combustible reactants are an alkali metal azide and a metal oxide which upon thermal initiation react to produce alkali metal oxide, metal and pure nitrogen gas which can be used to inflate an impact protection air cushion of an automotive restraint system.
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Citations
9 Claims
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1. A solid composition for generating nitrogen gas substantially free of noxious and toxic impurities, comprising essentially a mixture of alkali metal azide and at least a stoichiometric amount of a metal oxide selected from the group consisting of iron, titanium and copper oxides aNd mixtures thereof, said metal oxide being capable of reacting exothermically with the alkali metal azide and wherein the metal of the oxide is lower in the electromotive series than the alkali metal of the azide and is a metal other than the alkali.
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2. The composition according to claim 1 wherein:
- a. the alkali metal azide is sodium azide.
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3. The composition according to claim 2 wherein:
- a. the alkali metal azide is sodium azide forming about 62 parts per hundred by weight of the total composition; and
b. the metal oxide is copper oxide forming the remainder of the composition.
- a. the alkali metal azide is sodium azide forming about 62 parts per hundred by weight of the total composition; and
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4. The composition according to claim 2 wherein:
- a. the alkali metal azide is sodium azide forming about 70.9 parts per hundred by weight of the total composition; and
b. the metal oxide is iron oxide forming the remainder of the composition.
- a. the alkali metal azide is sodium azide forming about 70.9 parts per hundred by weight of the total composition; and
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5. The composition according to claim 2 wherein:
- a. the alkali metal azide is sodium azide forming about 76.5 parts per hundred by weight of the total composition; and
b. the metal oxide is titanium dioxide forming the remainder of the composition.
- a. the alkali metal azide is sodium azide forming about 76.5 parts per hundred by weight of the total composition; and
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6. A METHOD FOR RAPIDLY GENERATING PURE NITROGEN GAS COMPRISING:
- A. PROVIDING A HOMOGENEOUS MIXTURE COMPRISING ESSENTIALLY SOLID GRANULAR ALKALI METAL AZIDE AND AT LEAST A STOICHIOMETRIC AMOUNT OF A METAL OXIDE IN SOLID GRANULAR FROM SELECTED FROM THE GROUP CONSISTING OF IRON, TITANIUM, AND COPPER OXIDES AND MIXTURE THEREOF, SAID METAL OXIDE BEING CAPABLE OF REACTING EXOTHERMICALLY WITH THE ALKALI METAL AZIDE, THE METAL OF THE OXIDE BEING LOWER IN THE ELECTROMOTIVE SERIES THAN THE ALKALI METAL OF THE AZIDE AND THE METAL OF THE OXIDE BEING OTHER THAN AN ALKALI METAL, AND B. RAISING THE TEMPERATURE OF THE MIXTURE SUFFICIENTLY TO IGNITE IT.
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7. The method according to claim 6 wherein the alkali metal azide is sodium azide.
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8. The method according to claim 7 wherein the metal oxide is copper oxide.
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9. The method according to claim 8 wherein the particle size of the sodium azide is less than about 50 microns.
Specification