US1882190A - Explosive - Google Patents

Description

Patented Get. H, 1932 STTE GLENN ALBERT PRITCHETT, OF RENO, NEVADA.

EXPLOSIVE Application filed January 29, 1932. Serial No. 589,704.

My invention relates to explosives, and contemplates the production of a series of explosive mixtures or compounds of mutually difierent characteristics and uses. all of which however possess in common certain novel features and properties. The invention also contemplates a novel method of compounding explosives.

Principal objects of the invention are to provide a superior and inexpensive explosive product which will be free from certain serious disadvantages of explosives of the prior art hereinafter briefly indicated.

The invention includes the use of dinitrotoluene of approximately a freezing point which has not been used in the manufacture of explosives prior to my present invention. The novelty of my invention also resides principally in the elimination of certain ingredients heretofore regarded as necessary to the production of explosives of comparable grade. and in certain novel features of the processing of the ingredients. all of which will hereinafter be more particularly described and claimed.

The invention contemplates several varying formulae. each formula providing an explosive of differentgrade and influence. Dinitrotoluene is used in each formula. Th s material is commercially obtainable in various grades characterized b difi'erentfreezing points ranging from about C. to 65 C. I have found it necessary to use DYT having a freezing point not lower than C. in order that the material may exist in a crystalline condition in the product.

The lowest grade explosive contemnlated by mv invention contains the following ingredients:

Formula A Per cent Dmitrotoluene 10 Sodium nitrate 90 The sodium nitrate is sized between 8 and 18 mesh and thus introduced into the composition in relatively granular form. as distinguished from the pulverulent state in which this material has been used heretofore. The nitrate grains used in Formula A are such as pass an 8 mesh sieve and are retained on an 18 mesh sieve. Consequently, none of the grains are larger than S mesh and none are smaller than 18 mesh. The curve on the accompanying raph, hereinafter referred to, indicates the average size. I consider the proper sizing of the nitrate important and conducive to the improved efficiency of the resulting product.

The DXT is warmed to a temperature above its melting point, say C. for average material. and mixed with the nit-rate. The mixture is maintained above the melting temperature of the DXT during the mixing operation to prevent crystallization of the liquid until an intimate mixture is obtained.

Upon cooling. the D'ST adheres as an oily coating to the nitrate grains, protecting the nitrate from moisture. and minimizing friction. Each grain of the product is an independent explosive agent, combustion being transmitted from one grain to another when the mixture is set off. The relatively coarse character of the granular product prevents the explosive becoming dense and insensitive to the influence of detonators when packed tightly in machine loaded cartridges or tamped in blast holes.

The explosive product is solid at ordinary atmospheric temperatures. Disintegration and separation of constituents cannot therefore occur, and the efficacy and safety of the productare not affected by ordinary climatic changes. The explosive composition is superior in strength to ordinary black blasting powder and is comparable thereto in cost of production and safety in handling.

My product is equal in all respects to prior art explosives including relatively expensive sodium chlorate, which it has heretofore been thought' 'ne'cessary to use in an amount equal to atleast 25% of the total weight of all ingredients in order to produce complete combustion when even the best detonator is employed.

An important object of the invention 15 produce an explosive compound which will not pack densely, and to this end DNT is selected having a freezing point directly related to the size of the nitrate grains. The larger the annexed drawing, which formsv part of this application for Letters Patent, there is plotted a curve showing the ratio of grain size to DNT freezing points between 8 and 50 mesh and 65 and 25 C. The thickness of the curve indicates the amount of variation in the ratio of grain size and freezing point which may be practiced without materially sacrificing the benefits obtained by strictly observing the ideal ratios. -Thus, it will be noted that the ratio of DNT freezing point and nitrate grain size given for Formula A by way of example may be more or less departed from, especially by using DNT of a higher freezing point, since the nitrate grains in Formula A are large enough to prevent density of pack in the product. It may, however, be stated that with nitrate grains of the size prescribed for Formula A, the freezing point of. the DNT should not be lower than 40 C. It is important that the DNT be in the frozen state in the product, and the smaller the grains the less solidly frozen must be the DNT. Otherwise the product packs densely and becomes relatively insensitive to the action of ordinary fuse caps or electric exploders.

\Vhen substantially the ratio prescribed is followed a satisfactory low grade explosive compound is produced which is slightly higher in percentage of strength than ordinary black blasting powder, which will detonate consistently with No. 6 fuse caps or electric exploders, and which possesses resistance to friction, fire and impact superior to any other comparable explosive of which I am aware.

To provide a more quickly burning and stronger explosive, having otherwise all the advantages of the physical property of Formula A, I replace some of the nitrates of the formula with other ingredients, including a. chlorate, as follows:

Formula B Per cent Dinitrotoluene 10 Sodium nitrate 73 Sodium chlorate 15 Lime 5 pulp provides carbon and serves to absorb and retain any excess oil.

A still stronger explosive is provided by further increasing the proportion of chlorate, as follows:

Formula 6' Per cent Dinitrotoluene 11 Sodium nitrate 56. 5 Sodium chlorate 30 Lime .5 Wood pulp 2 In Formula C I prefer to use smaller sized nitrate grains e. g.. such as sieve between 10 and 20 mesh. To illustrate the latitude permissible in the ratio of DNT freezing point and nitrate grain size, it may be stated that with nitrate grains so slightly reduced in size compared with those of Formula A. the DXT may be of the same freezing point as that prescribed for Formula A, since in Formula C the nitrate grains are still large enough to prevent density of pack in tlie product.

A still stronger product is given by the following formulae:

Fm'mula D Percent Dmitrotoluene 10 Sodium nitrate 41 Sodium chlorate 39.5 Lime .5 Wood pulp -Q. 8 Mononitrotoluene 1 v Formula)? Percent Dinitrotoluene 10 Sodium nitrate 44 Sodium chlorate 39. Lime .5 Bagasse. flour 5 Mononitrotoluene 1 These two formulae produce products substantially equal in strength, Formula E being desirable where it is necessary to consider oxygen balance in the product and a lower carbon contentis required. Bagasse flour has almost twice the absorbent qualities of wood pulp. so that a smaller quantity may be used.

In Formulae D and E the nitrate grains are sized at not larger than 20 mesh. Such reduction in grain size necessitates usin DNT of a lower freezing point, to prevent ensity of pack, and to this end a small proportion of mononitrotoluene is added to the DNT. The freezing point of the mixture of the two toluenes in Formulae D and E should be not higher than 37 C.

In each formula the moisture content is less than 1%.

It is to be understood that the five formula set out hereinabove are 'ven merely by way of example of several em iments of the 1nvention. It will be understood of course that an indefinite number of other formulas are contemplated by the invention, when explosives of varying strengths are desired, all ex emplifying the characteristic ratio of toluene freezing pointand nitrate grain size; Furthermore. slight departures from the proportions of ingredients. temperatures, and grain sizes specifically set out in the specification and appended claims are considered within the spirit of the invention and within the scope of the claims.

I claim :7

1. An explosive including DNT and'sodium nitrate in which the DNT has a freez- 5 ing point not lower than 40 6., and the grains of nitrate are sized between Sand 18 mesh. and in which the DNT is carried as a coating on the nitrate grains.

2. An explosive as claimed in claim 1,

20 which contains substantially 10 parts of DNT and 90 parts of sodium nitrate.

S.- An explosive as claimed in claim 1 which contains substantially 10 parts of BN1, 7 3 parts of sodium nitrate and 15 parts of sodium chlorate.

4. An explosive as claimed in claim 1 which contains substantially 10 parts of DNT, 41 parts of sodium nitrate and 39.5 parts of sodium chlorate.

5. An explosive including DNT and sodium nitrate in which the freezing point of the DNT and the grain size of the sodium nitrate are related as follows: for nitrate grain sizes above 50 mesh to approximately 14 mesh the freezing point of the DNT varies directly with the grain size between substantially 25 C. and substantially 41 C., and for nitrate grain sizes above 14 mesh to approximately 8 mesh the freezing point of the DNT varies directly with the grain size between substantially 41 C. and substantially 65 C.

6. The method of compounding an explosive containing DNT and sodium nitrate in- 45 cluding the step of admixing DNT and sodium nitrate having the following relation: for nitrate grain sizes above mesh to approximately 14' mesh the freezing point of the DST varies directly with the grain size 59 between substantially 25 C. and substantially 41 C. and for nitrate grain sizes above 14 mesh to approximately 8 mesh the freez= ing point of the DNT varies directly with the grain size between substantially 41 C. and substantially 65C.

In testimony whereof I aflix my signature.

GLENN ALBERT PBITCHETT.