US1744693A - Detonator - Google Patents

Description

Patented Jan. 21, 1930 FRANK H. BERGEIM, OF 'WOODBURY, JERSEY, ASSIGNOR TO E. I. DU PONT DE NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELA- WARE .DETONATOR No Drawing.

This invention relates to the production of an improved detonator. More particularly it relates to a composition blasting cap containing erythritol tetranitrate.

Blasting caps are ordinarily made by pressing a base charge into a metallic shell, and on top of this is pressed a priming charge with or without a capsule, depending upon the kind of primer used. Among the explosives which have been used as base charges are trinitrotoluene, tetryl, nitrated ivory nut meal, and smokeless powder. The most commonly used primers are mercury fulminate and lead azide.

While the above mentioned base charges have been used with a certain degree of success, it is desirable that they should possess a greater degree of sensitiveness to detonation by a primer, thus insuring regular performance, a matter of considerable importance in blasting practice. A shot that fails in blasting is a source of danger and expense.

An object of my invention is to provide a detonator that insures more regular performance than has hitherto been possible. Other objects will appear as the description proceeds.

I have found that desirable results can be obtained by incorporating erythritol tetranitrate into the cap composition. The erythritol tertanitrate may be incorporated in various Ways. I may, for example, use any of the usual base charges in admixture with erythritol tetranitrate, or, if I desire a particularly powerful cap, I may use erythritol tetranitrate as the sole base charge. I have found that a cap using erythritol tetranitrate alone as a base charge is more powerful than any of the commercial blasting caps now used. This great strength is of advantage in insuring transmission of the cap explosion to the main bulk of blasting explosive. It has also an economic advantage in that it permits using smaller charges than can be used successfully with the ordinary base charges. A further advantage obtained by using erythritol tetranitrate as a base charge is that successful caps can be made using mercury fulminate without a capsule as 9.

Application filed May 3, 1928. Serial No. 274,966.

primer. This effects a saving both in operation and materials.

In my U. S. Batent 1,691,954, dated Nov. 20, 1928, I have pointed out that erythritol tetranitrate has a melting point of 61 C. This low melting point makes this compound well adapted to casting and I have found that when cast this material can be detonated by means of a primary detonating compound such as mercury fulminate and in this form constitutes a very powerful detonating agent.

From the foregoing it will be seen that my invention is of wide application, and that, whereas I have confined my description of its use to blasting caps, it is understood that erythritol tetranitrate is equally well adapted to use in other detonating devices as, for example, booster charges for high explosive shells, which charges perform the same function with respect to the main charge in the shell as does the base charge in a blasting cap with respect to the dynamite.

The following are by way of illustration examples of blasting caps made in accordance with my invention: For a cap containing no inner capsule I may use a pressed base charge of erythritol tetranitrate ranging from 2 grains to 10 grains, depending on the strength of cap desired, with a superimposed charge of 8 grains of a 90-10 mixture of fulminate and chlorate. For a cap containing an inner capsule, I may use a base charge of 2 to 8 grains of erythritol tetranitrate with a top charge of 5 grains of 9010 fulminate-chlorate mixture.

As many apparently widely different embodiments of this invention may be made without departing from the spirit thereof, it is to be understood that I do not intend to limit myself to the specific embodiments thereof except as indicated in the appended claims.

I claim:

1. A detonator having a main charge comprising erythritol tetranitrate.

2. A detonator compnising erythritol tetranitrate and a primary detonating compound.

3. A blasting cap having a main charge comprising erythritol tetranitrate and a primer comprising fulminate of mercury.

4. A detonator having a main charge comprising cast erythritol tetranitrate.

5 5. A detonator comprising a base charge of cast erythritol tetranltrate and a top charge of a primary detonating compound. I 6. A blasting cap comprising a base charge of cast erythritol tetranitrate anda, priming 1Q charge of fulminate of mercury. p

In testimony whereof, I aflix my signature.

FRANK H. BERGEIM.