US2495868A

US2495868A - Detonator

Info

Publication number: US2495868A
Application number: US644264A
Authority: US
Inventors: James T Power
Original assignee: Atlas Powder Co
Current assignee: Atlas Powder Co
Priority date: 1946-01-30
Filing date: 1946-01-30
Publication date: 1950-01-31
Anticipated expiration: 1967-01-31

Description

Jan. 311, 1950 T POWER 2,495,868

DETONATOR Filed Jan. so, 1946 Fi yl Fi .2

James 1% INVENTOR 'A-TTORNEY Patented Jan. 31, 1950 UNITED "STATES 7 'nE'roNA'roit James. T, Power, Wilmington, DcL, aSSlgnor to Atlas Powder. Company, Wilmington, Del., a

corporation of Delaware Application anuary 30, 1946;"Serial'No. 644,2'dd

. 6 Claims.

- The P nt application relates to detonators.

, An object of the present invention is the pro-:

vision of a new detonator employing a new explosive charge.

Another object of the present inventionis the provision of .a detonator containing a base charge of nitrated dextrose polymer.

As is well known, detonators are employed to initiate explosive materials. Customarily a detonator comprises a cylindrical tubular shell into which is charged a detonating explosive; In the fuse cap type of detonator, the shell is open ended to provide a place for insertion of a fuse for initiation.

r The electric blasting cap type of detonator is. 1- initiated by means of an electric current/tin addition to a detonating explosive charge, an. electric detonator contains an ignition element such as a bridge wire, spark gap, or electric match head. Leg wires lead out of the shell from the electric ignition means, and the top of the shell around the leg wires is usually sealed with a fusible sealing composition. 7 3

Most modern detonators are compound. That is to say, they contain a plurality of different explosive charges superimposed one on another. The charges which produce the main explosive force in a detonator are called base charges and are charged into the bottom of the detonator. A single base charge or a number of different base charges superimposed one on-anothen; may be employed. Materials, which make good base charges are themselves quite often diflicult to initiate, and to permit proper initiation a primer charge is usually superimposed upon the top base 1 charge. Primer charge materials are usually rel-'.-. atively more sensitive and lesspowerful than base charge materials. They often may be initiated by the spit of a fuse or by an electric ignition element. Sometimes, however, an additional flash charge composed of highly inflammable material is superimposed over a primer charge to reinforce and supplement ignition by a fuse or electric ignition element.

According to the present invention nitrated dextrose polymer is employed as a charge material in detonators. Nitrated dextrose polymer has properties of sensitivity, power, and stability which make it particularly well suited for use as a base charge material.

Dextrose polymer is a synthetically prepared glucose poly-anhydride. Linkages between glucose units are chiefly glucosidic, but there is also some non-glucosidic etheriflcation.

Dextrose polymer may be prepared according 55 to the methods set forth in Patent 2,375,564 issued May 8, 19451in'the name of Gerald J. Leuck.

' Dextrose polymer may be obtained with varying average numbers of glucose units per molecule. It is usually found that the number of hydroxyl groups per unit and the water solubility decrease as the average number of units per molecule increases. The nitrated dextrose polymer used in the present invention should usually be-prepared' from dextrose polymer containing an average of at least three glucose units per molecule, and nitrated dextrose polymer prepared from dextrose polymer having an average of as many as about 35 glucose units per molecule may be employed. It has been found that very desirable results are obtained when there are an average of from about! to about 10 glucose units in the molecule.

The drawing shows generally two detonators prepared according to the presentinvention.

Figure lis a longitudinal section of a fuse cap embodiment of thepresent invention.

Figure 2 is a longitudinal section of an electric blasting cap embodiment in the present invention. 'In both figures. 5 represents a detonator shell,

IBrepresents a base charge of nitrated dextrose polymer charged into the bottom of shell 5, and

9 represents a primer charge superimposed on base charge [3."

In Figure 1, showing a fuse cap, it! represents I a1flash charge superimposed'on primer charge 9.

"In Figure 2,. showing an electric blasting cap, 8 represents a conventional match head assembly, II and 'IZrepresent sealing compositions, and

6 and I represent leg wires for connection to" a' source of electric current."

The following example describes the. prepare-- tion'of nitrated dextrose polymer.

Example I grams of a solution of mixed acids having the following composition were prepared:

Per cent Nitric acid 35.0 Sulfuric acid 58.0 Water 7.0

The resulting mixture was drowned by pouring it into one liter of water. The product was filtered and given three one-hour washes at 70 to 80 C. using one liter of water for each wash. The washed product was air dried at room temperature. A yield of 14.9 grams of crude product resulted. This crude product was dissolved in 25 cc. of acetone. The acetone solution, which was acid to litmus, was agitated with one gram of hydrated lime to remove the acidity. After filtering the solution, the clear filtrate was fed with vigorous agitation into 20 times its volume of water at 25 C. The nitrated dextrose polymer was filtered off and dried. 12.6 grams'of product.

were obtained.

The following examples show the preparation of blasting caps containing ,base charges of nitrated dextrose polymer.

Example II Gilding metal fuse cap shells 0.222 inch in diameter were eachncharged with 0.23 gram of nitrated dextrose polymer prepared as described above. These base charges were pressed at 150 pounds pin pressure, and over each of them were charged 0.175 gram of nitromannite primer charge and 0.06 gram of flash charge composed of a mixture of 75% diazodinitrophenol and 25% nitromanm'te. The flash charges and primer charges were pressed together at 30 pounds pin pressure. detonators produced A lead plates.

Example III A number of gilding metal electric blasting cap shells 0.260 inch in diameter were each. charged with 0.29 gram of nitrated dextrose polymer and 0.16 gram of nitromannite. These two charges were pressed together, under an inner capsule, at 125 pounds pin pressure, and a conventional electric match head assembly was then sealed into the tops of the shells to complete the detonators. These detonators gave sand test results of 53 grams- The nitrated dextrose polymer of this invention may be used with or without confining capsules and it may be used with other base charges as, for example, tetryl, TNT, pentaerythritoltetranitrate, and cyclonite. These other base charge materials may be mixed with the nitrated dextrose polymer or they may be used .as separate charges superimposed upon or charged under the nitrated dextrose polymer. Nitrated dextrose polymer base charges may be initiated by any of.

the conventional primer charges such as nitromannite, diazodinitrophenol, mercury fulminate and lead 'azide.

Single charge detonators may be prepared from On firing in lead plate tests, these a about 35 glucose units per molecule, and a primer charge.

2; A fuse cap comprising a shell, a base charge comprising completely nitrated dextrose catalytic polymer, said polymer containing an average of from about 7 to about 10 glucose units per molecule, and a primer charge.

a. 3; An electric blasting cap comprising a shell,

.abase charge comprising completely nitrated dextrose catalytic polymer containing an average of no more than about glucose units per mole- ;cule", a primer charge and an electric ignition element. 1 1 4. An electric blasting cap comprising a shell,"

a base charge comprising, completely nitrated dextrose catalytic polymer, said polymer containing an average of from about '7 to about 10 glu.- cose units per molecule, a primer charge, and an electric ignition element.

5. A detonator comprising a shell and a base charge comprising completel nitrated dextrose catalytic polymer containing an average of .no;

' more than about 35 glucose units per molecule.

6. A detonator comprising a shell and a base,

- charge comprising completely nitrated dextrose -catalytic polymer containing an average of at; -least 3 and no more than about 35 glucose units per molecule.

, JAMES T. POWER.

REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date Moran May 11, 1926' De Crater Nov. 8, 19322 Crater Aug. 15, 1933* Lewis Feb. 20,19342 FOREIGN PATENTS Number Country Date eosyss Snelling Aug. 12, 1924' Wrightsm-an Dec. 15, 1931' Large Mar. 26, 1940" Germany Nov. 17, 1934