US2071710A - Ignition composition - Google Patents

Description

UNITED STATE "10, main Patented Feb. 23, 1931 PATENT. OFFICE Alfred Schmid, Berlin-Dahlem, Germany; asslguor to Oswald F. wysspzurlch, Switzerland No iii-swing. Original application August .27, I

1982, sel'lalNo. 630,702. Divided and this application November 28, 1933, .In Germany August 28. 1931 Serial No. 100,141.

I have inven'ted certain new and useful improvementsin ignition compositio this forming a division from U. S. application 630,702, filed August 27, 1932 and for whichI have filed appli- 5 cations in Germany, August 28, 1931 and Switzerland, February 8, 1932, and of which thetollowing is a specification. invention relates tures and to theirmanuiacture and has for its ture, the combustion of which takes place without flameand without} the production of poisonous andbad smelling gases. l

The known ignition mixtures used for "start- 7 l6 ingcombustionprocessesgenerally consistoi the i following constituents:

(a) Easily decomposable substances yielding oxygen by decomposition, such as chlorates nitrates, chromates, vperoxides, and the like. I

:(b). Substances easily inflammable at low temperatures such as phosphorus, sulfur, carbon or compoundsoi the same.

(c) Additions of ,hard and chemicallyine'rt' substances increasing friction, such-as; quartz. clay, pumice stone and'the like.

i (d) Binding agents such as glue, starch, gum arabic and the like. 7 A

e (e) Substancespreventing an explosive combustion such as zinc oxide, iron oxide and the Due to the presence it object to provide for a safety ignition mixof the subst nces men to safety ignition mix-- on combustion do not furnish volatile combustion products but solid oxides in form of a pow (let. The main feature or the new ignition mix-1 tures is the absence of phosphorus, sulfur, carbon or their compounds, the inflammability of '6 the mixture being solely due to the combination of oxygen yielding substances with easily ignitable metals. e he For many purposes ordinary metals would yield ignition mixtures, the ignition of whichwould '10 be too diflicult for the purpose in question. The invention provides for means to bring these metals into a form, inwhich their rapid oxidation or combustion is facilitated. a

It is known, that certainmetals such as iron or cobalt maybe obtained in the pyrophoric form by reducing at relatively low temperatures suitable compounds of these metals with streaming hydrogen. These pyrophoric metals are, however, ignited and combusted by contact with oxy- 2o genor air at room temperature. This pyrophoric form of metals is not suitable for the purpose oi the invention 'and the invention therefore has for its further object, to provide for a method, which enables the manufacture of metals in such a form, that they may be ignited with air at temi peratures above atmospheric temperature, preftioned under (b) all known ignition mixtures are combusted with flames and evolution of poisonous and evil smelling-gases. Their use is thereflames oi the evolved gasesare dangerous or noxious. 1

' The present invention provides for a safety ignition'mixture which may easily be ignited on 40 the usual iriction surfaces for safety matches and are combusted without flame and without.

50 ages for the cigars, cigarettes or matches.

35 tore impossible in alithose cases, where open 'erably above 50C., but below 300' C. I have named this form of metals, whichis an intermediate form between pyrophoric and normal form, semi-pyrophoric. This. method for making semipyrophoric metals consists in a reduction of metal compounds suitable for the manufacture of pyrophoric metals under such modified reducing conditions that neither the pyrophoric nor the normal form is obtained or in treatment of pyrophoric metal which makes them more difliculty ignitable. The reduction or the metal compounds may be carried out by thermal decomposition in presence 01 inert. gases or by treatment with 40 hydrogen at raised temperatures. Temperature 'and duration of these treatments must be kept within limits, outside 0! which pyrophorlc or normal metals are obtained. Starting materials for the method according to the invention-are inorganic or organic metal compounds such as According to the invention Rthe phosphorus,

sulfur orthe. like present in the known ignition mixtures is replaced by metals with a'suiiiciently low ignition temperature such as magnesium,

to aluminium, zinc, iron, cobalt and the like, which oxides, nitrates, carbonates, sulfates, oxalates,

tartrates or the like. Pyrophoric metals may be converted into semipyrophoric metals by a shorter or longer heat treatment in presence of inert gases, such as nitrogen, hydrogen and the like or by mixing or combining them with substancegnot self-ignitable by contact with air, such as oxides.

In both cases for the manufacture or semi- 5 the expert in finding the semi-pyrophoric metals other than iron or'semi-.

starting materials] pyrophoric metals the duration 01' the treatment is a function of the temperature. Moreover temperature and duration of the treatment are difl-' erent for different metals, gases and pressures employed. It is therefore not possible to give generaldata for temperature and duration of the treatment, but the following example may lead conditions for making pyrophoric iron from other or by a modified method. 10 gr. of ferrous oxalate are heated to about 400? C. instreaming hydrogen, which has been dried by passing it through concentrated sulfuric acid before entering the reaction zone and which passes this zone at a moderate rate corresponding to about two gas bubbles leaving the sulfuric.

acid perrsecond.

When the amount of gases leaving thereaction zone decrease,.which is the case after aboutv one'ho'uryth'e reaction is finished. The heating i'sstopped and a rapid cooling is eflected by pass- ,ing hydrogen through the reaction zone. When room temperature has been reached a black pw-- by contact with der is obtained 'not ignitable air, at room temperature, but igni table,. when contacting it with air at about 180 C. v 1 r 28 parts of the semi-pyrophoric iron; produced in the manner described are mixed with 25.parts of potassium chlorat -18 parts of powdered burnt clay. The mixture is powdered and mixed while stirring with 80 parts of a 4% solution of collodion in volatile organic solvents, some ether and alcohol being added to the peppy mixture if necessary. The mixture is 1 part of pyrolusite and:

placed on the top of a cigar or cigarette in any convenient manner, thus obtaining a firmly adhering ignition head on the article after evaporation of the volatile solvent at the air.

The igniting mixture described above may contain other substances, such as fillers and the like, or may becombined with other protechnic mix tures. It may be arranged on any inflammable carrier and thus serve to light any combustible substance.

The solution of collodion employed as binding agent in the above example may be replaced by solutions of other binders, such as acetyl cellulose and the like,.in volatile organic solvents, such as alcohol, ether, acetone, amyl acetate and the like.

'Also aqueous solutions of glue, starch, gum arable and the like may be employed, although binders containing volatile organic solvents are preferred, as the solidification of the ignition mixtures on their carriers is accelerated, when the binder contains volatileliquids as solvent. The amount of binder usedis kept as low as possible and preferably such binders are employed, which are easily and completely combusted without the evolution of noxious and bad smelling gases.

I claim:

1. Safety ignition mixture ignitable by friction on friction surfaces, consisting of aimixture of substances yielding oxygen, semi-pyrophoric iron, abrasive substances and binding agents.

I 2. Safety ignition mixture ignitable by friction on friction surfaces, consisting of a mixture of substances yielding oxygen, semi-pyrophoric iron, zinc dust,abrasive-substances and binding agents.

ALFRED SCHMID.