US2275569A - Loading pasty solids - Google Patents

Description

Patented Mar. 10, 1942 LOADING PASTY SOLIDS Walter 0. Sneliing, Allentown, Pa., asslgnor to Trojan Powder Company, Allentown, Pa.

No Drawing. Application April Serial No. 391,213

6 Claims.

This invention relates to loading of pasty solids and has for its principal object the provision of a method of so loading such material as to in-- crease its loaded density. A specific object of the invention is to charge 80-20 amatol into a shell or bomb to a density as great as is possible with a 5050 amatol which may be poured or cast into the shell cavity.

Amatol is the general name for an explosive consisting of ammonium nitrate and trinitrotoluene in various percentages, frequently in equal parts, this explosive then being known as so -o amatol. Since an amatol containing as little as one-filth of trlnitrotoluene can be detonated full eilectiveness it would be highly desirable to substitute such till-20 amatol tor the more common till-5o amatoi except for the appreciable differences in gravity.

When. amatol is formed oi equal parts of the two ingredients it can be poured into a shell in just the same way that the straight TNT can be loaded and therefore can have a high density whereas amatol containing a greater proportion oi ammonium nitrate must always be extruded, tamped or packed into the cavity as a hot pasty solid rather than as a flowing liquid because it does not become a liquid at temperatures or to" above the melting point of TNT at 302 C. id therefore must be into the shell oi oi eque ,"ts oi" lnlmonium nitrate and, triniltrotoiuene as high as 1.55 whereas the amatol having tour parts oi ammonium nitrate to one of lll'l can be given a loading density of me only with difitlculty. This of course means that the total weight of the 80-20 explosive that can be loaded into a shell is almost a tenth less than is possible with the Evil-50 amatol. The bulk or loading density of titamatol is lower because the ammonium nitrate crystals do not melt at this temperature range, and there is not enough fluid TNT to flow into the porous spaces and fill them. When the density of the solid crystals is considered, that the particular cavity to be filled. I have found it very convenient to form the particles or grains into small round spheres or pellets particularly since these pellets can readily be made in available pellet presses, using a pressure of say two tons per square inch. By using pellets of relatively small size the charge can more readily be loaded and the transfer of heat from the pellets which may be at room temperature or may be H chilled to any desired degree will not take up all of ammonium nitrate (1.72) is slightly more favorable than that of TNT (1.65), hence the basic soundness of the idea of highly compressing the material into pellets.

My method contemplates treating any material the heat of the hotter matrix material until loaded in place.

In the form of my invention in which I am most interested the material to be loaded is an amatoi in which the major portion of the mixture is ammonium nitrate. When four parts of ammonium nitrate to one part of trinitrotoluene are heated together at a temperature about equal to the boiling point of water or somewhat less, an amatol. is termed having an apparent density or apparent specific gravity of 115, The amatol thus made is divided into a chosen proportion, using a major portion as a matrix without luv ther treatme t and treatind the minor portion. whleh may he little as one iourthz but is prefierezloly from one-third to one-hall the total mix, so as to increase its density to or higher, preferably by pelleting the amatol in a pellet press, using pressure which may couveiuently vary as desired from as little as 5,669 pounds per square inch to as much as 30,000 pounds per square inch, these figures giving pellets having a density which may vary from 1.50 to 1.65 or even slightly higher. The compressed pieces may be of other shapes, such as cubes, lozenges, etc., but I prefer the ball shape.

When the shells are ready to be loaded the major portion of the amatol running halt to twothirds of the total mix is warmed to a point at which the trinitrotoluene will melt and the mixture becomes a pasty solid. The compressed blocks or pellets are now mixed with a hot -20 amatol in its pasty condition, providing a charg- -ing mixture in which the high density pellets are each su'rrounded by a matrix of the untreated but hot 80-20 amatol which has a. density of about 1.40. The shells may be loaded in any desired manner with the mixture or by alternate layers of matrix and compressed lozenges separately tamped in place. Densities running from 1.45 to 1.50 maybe obtained with. care, and a shell may be loaded to adensity of 1.55 or even higher under specially favorable conditions.

As an example of effectiveness ofthis manner of loading, the normal load which can be charged into a hundred pound demolition bomb is 50 pounds of 50-50 amatol; with untreated 80-20 amatol the best loading is about four pounds short of this weight because of the difierence in density, while with the present invention a charge of nearly if not fully 50 pounds of 80-20 amatol may be loaded.

Up to the date of the present invention it was never known to be possible to load 80-20 amatol to any density equal to or even substantially equal to the density of the poured 50-50 amatol. By the use of this invention one can load 80-20 amatol not only to a higher density than was possible before my invention, but it is possible to materially facilitate the loading operation as the time of loading is reduced by the use of compressed blocks or pellets of high density amatol in the matrix of 80-20 amatol of ordinary density. In general the admixture of the pellets not only tends to increase the density of the mass of amatol, but by the sharing of the heat present in the freshly-made 80-20 amatol with the earlier made pellets of highly compressed 80-20 amatol, the cooling of the bomb charge is facilitated, and the length of time that the bomb must remain on the loading fioor in process 01 being loaded is considerably shortened. The length of time can still further be shortened by chilling the pellets before mixing with the hot amatol orby increasing the size of e the pellets or both.

What I claim is: i

1. The method of increasing the density of a charge of amatol in which the percentage of the TNT is less than required to make the amatol a flowing liquid at a temperature within ten or twenty degrees above the melting point of the TNT; which comprises compressing a minor por- 2 amuse tion of the amatol into pieces-oi a density in excess of 1.50 at a pressure from five to thirty thousand pounds per square inch, mixing such pieces with a major portion of the uncompressed amatol ata temperature well above 80.2 C., and charging theemixture while still hot into the cavity to be filled.

2. The method of charging a shell with amatol in which the percentage of the ammonium nitrate is appreciably greater than that of the TNT; which comprises compressing from about onefourth to about two-thirds of the charge to pieces of a density of at least 1.50, heating the uncompressed portion of the charge to a pasty condition to form a matrix, mixing the compressed pieces with the hot matrix and charging the shell with the mixture, whereby to obtain a charge of greater density than if the amatol were loaded into the 'shell entirely as a pasty solid.

3. The process of claim 2 in which the amatol is -20, the compressed portion is from onethird to one-half the charge and is in pellets with a density of at least 1.50 and the final density of the filled charge is above 1.45.

4. The method of filling a cavity with a material which is pasty at ordinary filling temperatures, which comprises compressing a portion of the charge into pieces of solid form with a density above 1.42, warming a portion of the untreated material to form a matrix, mixing the solid compressed material with the pasty matrix,

and loading the cavity with the mixture while the matrix is still pasty.

5. The method of claim-4 in which the pieces are pellets compressed at a pressure greater than two tons per square inch and comprising at least one-fourth of the filling charge, and. the cooling of the charge is facilitated by the transfer of heat from the hot matrix to the relatively cool pellets.

6. An ainatol charge comprising a body of amatol, with a density below 1.45 having embedded therein a proportion, exceeding onefourth, of particles of amatol compressed to a density above 1.45.

WALTER O. SNELLING.