US2173271A - Ignition composition - Google Patents

Description

Sepit. 19, 1939. BURROWS 2,173,271

IGNITION COMPOSITION Filed July 50, 1957 u 'l i l I I l I I x 1 I I I Lawzon A. Burrows INVENTOR.

A TTORNEYS.

Reiterates! gept. 119, 3%39 2,2732%1 myrrh snares enter @FFHE 2,l'i3;2'ill roNlI'rroN oosmosmoa Lawton A, Burrows, Wenonah, N. 3., asslgnor to IE. ll. du lPont de Nemo & (Company, Wilgton, Del a corporation oil Delaware Application 30, 1937, Serial No. 156,483 12 Claims. (on. 52 -2) The p t invention e tes to blasting initiunderstood, however, that the compositions indiators, and in particular to new and improved i cated constitute merely preferred embodiments nition compositions for use in various types of of my invention for the purpose of more adequate said initiators. illustration, and that the scope of the invention 5 As is well known, ignition compositions for use is not to be limited by the details set forth in these in blasting initiators generally, must be highly examples.

sensitive to heat in order to give effective per- Example I formance. Unfortunately, the materials known to the art which possess this required sensitive- Per cent ness to heat, likewise tend to be sensitive to shock, Ptflsium chlorate w friction or static charges. Consequently, such calcmm hmphmme 30 materials are hazardous and present serious Pym smokeless powder problems, not only during the course of manufac- This composition is desirably employed as a ture, b in the ha of the finished product loose ignition charge in the various types of blast- 35 thereafter. ing'initiators. It may be grained according to 35 Furthermore, the ignition compositions known any of the well known procedures in order to fato the art are frequently unsatisfactory for the cllitate loading into theinitiator shell.

reason that they are incompatible with certain of Example H the metals and alloys commonly employed for l Per cent so. ini iator shells, and have a corrosive efiect on Calcium hypophospmte so said shells Potassium nitrate 45 The object of my invention is to provide a new sulfur 10 and improved ignition composition which is relatively insensitive to shock, friction and static composit o is ew s highly desirable as electricity. A further object is to provide such a a loose charge i blasting initiators generally- 25 composition whichis satisfactory for use with the Example 11 nzetasllslalnd alloys coonly employed for initi- Per cent a or e s. A still further object is to provide an ignition composition which is readily ignited and gfimfigi ggg I y possesses uniform and rapid burning properties. calcium suicide 20 3 Other objects will be discussed as the invention is Nitmstamh further described hereinafter. I

I have found that these objects are accomme foregoing compwmonis especially suitable plished according to the'present invention, by the $8 an ignition cflmposition r initiators h preparation of ignition compositions comprising concave plug type. An inappreciable amount of 35 v calcium hypophosphite and an omdizing agent, nitrostarch is employed as a binder and to accom- While I find that satisfactory ignition oomposip sh the parti selatlnization 0f the compositiontions are formed from calcium hypophosphite and Any 0f the solvents commonly p y f r Such an oxidizing agent alone, I prefer to employ compurpose may be used to assist in this gelatlnizapositions comprising calcium hy o ho hit an tion. The resulting compositions show no tend- 4o oxidizing agent, and at least one readily ignltible ency to become friable or to disintegrate on storfuel. Many different types of fuels are suitable age, but remain in position in the concave plug, as including both organic and inorganic fuels. As compact coherent massexamples of organic fuels, I may employ ground In the manu actu e of electric q l I prefer smokeless powder and the like. As inorganic o e p y apre e charge consisting of c fuels, I prefer to employ finely divided atmos- 0 1ml hypoph flh t Potassium chlorate, and at pherically stable metals such as magnesium, zirleast one of the metallic or alloy fuels mentioned conium, and aluminum, atmospherically stable in the foregoing, such as magnesium, calcium silialloys such as antimony-iron, ferro-silicon, silicide or the like. This base-charge is preferably con-manganese carbon, calcium silicide, and ignited by means of a loose superposed charge metalloids of group VI of the periodic table. consisting of calcium hypoph phi e and p Preferred ignition compositions according to sium chlorate. my invention and prefered adaptations of the By way of more exact description, reference is same to the various types of blasting initiators, made to the accompanying drawing. in which are set forth in the following examples. It is Fig. 1 shows an ordinary fuse type blasting cap.

Fig. 2 shows an electric blasting cap of the concave plug type, while Fig. 3 shows an electric squib of the closed type. Similar numerals refer to similar parts throughout the several views.

Referring to Fig. 1, I designates the shell of the initiator which is made of gliding metal or other suitable material, 5 the base charge preferably tetryl, t a primary charge, e. g. mercuryfulminate enclosed in the capsule 3, said primary charge being superimposed on the base charge. 2 representsthe ignition composition of my invention, which composition is to be fired by the flame from a fuse. Referring to Fig. 2, the ignition composition 2 of the present invention is shown in a concave plug 9, in close relationship with the primary charge 4, which is superimposed on the secondary charge 5. The ignition composition 2 is fired by means of an electric current passing through the leading wires 6. bringing to incandescence the bridge wire it] which passes thru the ignition composition. The leading wires are held in place by means of the conical bridge plug 9, with the waterproofing composition 8 above the bridge plug and the sulfur composition 1 at the top Fig. 3 shows anelectric squib having the loose ignition composition 2, superimposed on a pressed base charge I I, which preferably includes calcium hypophosphite, a fuel and an oxidizing agent. The ignition composition 2 is fired by electrically heating the bridge wire III, to incandescence.

It is apparent from the foregoing that the calcium hypophosphite-containing compositions according to the present invention are satisfactorily adapted for use as ignition compositions in the various types of blasting initiators. The presence of the calcium hypophosphite as a chief ingredient imparts to the resulting composition the highly desirable properties of low sensitiveness to 'shock and friction, but without any diminution ing devices in which said compcsitiom are cmployed.

It is understood that the various examples cited herein are given by way of illustration. Many variations may be made without departing from the spirit and scope of my invention. For example, the composition recited for use in a concave plug is suitable not only as the ignition composition of a blasting initiator, but also as the ignition composition of a delay squib. I therefore, intend to be bound only by the following claims.

I claim:

1. An ignition composition comprising calcium hypophosphite and an oxidizing agent.

2. An ignition composition comprising calcium hypophosphite, an oxidizing agent and a fuel.

3. An ignition composition comprising calcium hypophosphite, an oxidizing agent and an inorganic fuel.

4. An'ignition composition comprising calcium hypophosphite, an oxidizing agent and an atmospherically stable metal.

5. The ignition composition of claim 4 wherein the atmospherically stable metal comprises magnesium.

6. An ignition composition comprising calcium hypophosphite, an oxidizing agent and an atmospherically stable alloy.

'7. The ignition composition of claim 6 wherein the alloy comprises calcium silicide.

8. An ignition composition comprising calcium hypophosphite, an oxidizing agent and a metalloid of group VI of the periodic table.

9. The ignition composition of claim 8 wherein the metalloid comprises sulfur.

10. An ignition composition comprising calcium hypophosphite, an oxidizing agent and an organic fuel.

11. The ignition composition of claim 10 wherein the organic fuel comprises ground smokeless powder.

12. An electric squib which includes a base charge comprising calcium hypophosphite, an oxidizing agent and a readily ignitible inorganic fuel, and a superposed ignition charge comprising calcium hypophosphite and an oxidizing agent.

LA'WTON A. fEiiiTFtH-QWS.

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