US1706517A - Blasting explosive - Google Patents

Description

Patented Mar. 26 1929.

UNITED STATES PATENT OFFICE.

LEAVIT'J. N. BENT, OF HOLLY OAK, DELAWARE, ASSIGNOR TO HERCULES POWDER COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

BLASTING nxr'iosrvn.

No Drawing.

My invention relates to an improvement in blasting explosives and more particularly to that type of explosives known as permissible explosives and which are used more particularly in coal mines.

Explosives of the type to which my 1nvention relates have heretofore included in their composition explosive ingredients, a carbonaceous ingredient and a sensitizer. For example, such explosives comprise ammonium nitrate, sodium nitrate, nitroglycerine and a carbonaceous material such as, wood meal, sawdust, bagasse and the like.

In selecting the carbonaceous material a material of low density and desirable absorbency has been sought in order to obtain an explosive of maximum low density and one in which the nitroglycerine, or other liquid explosive, used as a sensitizer will not be unduly absorbed, especially in warm weather, in order that the explosive will be of desired sensitivity without the use of an excessive amount of the sensitizer.

Heretofore in explosives of the character indicated, it has been customary to utilize finely divided spruce or white pine wood as the carbonaceous ingredient and it has been suggested to use bagasse, or the waste of sugar mills, and woods having an extremely low density, as for example, balsa wood. Spruce and white pine wood are relatively dense and bagasse and balsa wood are relatively diflicult to obtain and are undesirably absorbent.

Now it is the object of my invention to provide a carbonaceous material for use in explosives which will have desirable low density and absorbency, which will be readily produced and which may be effectively produced from the woods heretofore used and from woods not heretofore usable, such as southern yellow pine, which has not been adaptable for use in explosives because of high density and undesirably low absorbency. Further, it is the object of my invention to produce a material of the character indicated for use in explosives, which will have a low density enabling the produc- Application filed July 26, 1927. Serial No. 208,661.

tion of explosives giving high cartridge count per unit of weight and which W111 have a desirable absorbenc enabling ellicient impregnation with sa ts, components of the explosive, where desirable, and enabling a desirable incorporation in the explosive of nitroglycerine, or other liquid explosive, used as a sensitizer.

In the production of acarbonaceous material for use in explosives in accordance with my invention, wood, which may be spruce, white pine, southern yellow pine, or other wood, and which has been chipped or finely ground, is subjected to treatment, in a closed container, with an elastic fluid at high pressure and temperature and then discharged into an area of low pressure, as atmospheric pressure. The treatment with the elastic fluidis preferably efiected through the use of steam and the treatment continued for such time as may be necessary to efiect e ualization of the pressure within and without the particles of wood, while at the same time avoiding charring or disintegration of the wood. When a very high pressure treatment is used and the temperature of steam at such pressure is injuriously high, the wood ma be given a preliminary short treatment with steam and then subjected to treatment with another fluid, for example, air, under a pressure greater than the steam pressure and which may be desirably high without at the same time being at a temperature which will injure the wood.

The wood, after treatment with an elastic fluid, as indicated, is discharged from the chamber under the pressure therein, into an area of relatively low pressure, as atmospheric, which causes the pressure within the particles of wood to explode the particles, disrupting the fibres thereof and efi'ecting disintegration of the wood. In the discharge of the wood from the closed chamber, the pressure therein is desirably maintained and the discharge is preferably effected progressively through a narrow or re stricted opening, in passing through which cordance with the method disclosed in the U. S. patents to William H. Mason, No. 1,586,159, dated May 25,. 1926, and No. 1,578,609, dated March 30, 1926, the fluid should have a pressure of at least 275 pounds to the square inch and may be as high as from 300 to 600 pounds per square mch. Where the wood is first treated with steam at high pressure and temperature and then with, for example, air, at a higher pressure than that of the steam, the pressure of the steam may be say about 300 pounds per square inch and the air may be under a pressure of from 400 to 600 pounds per square inch, or even as high as 1000 pounds per square inch. The treatment of the wood with an elastic fluid at high temperature should be limited to a short period of time, say a few seconds, in order that the wood shall not be charred or distintegrated by the heat, the subsequent treatment with air, if

such is utilized, may be for a longer period.

The distintegrated fibre obtained by discharge of the wood from the container may be Washed and dried before use, or it may be extracted, or, if it is produced with the use of a resinous wood, it may be extracted with a solvent for rosin, as gasoline or other light hydrocarbon solvent, for the recovery of rosin.

The distintegrated wood may be used in explosive compounds in amount from about 1% to about 18% and may be used in explosives of any well-known compositionas, for example, in a composition containin the following ingredients in amounts within the ranges set forth in the following formula:

Per cent. Ammonium nitrate 25-85 Sodium nitrate 0-25 Nitroglycerine, or other liquid H. E..- 515 Disintegrated wood 1-18 The disintegrated wood may be utilized with other carbonaceous materials if desired and, as has been indicated, the distintegrated Wood may be impregnated with ammonium and/or sodium nitrates and with which other salts may be included.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is 1. -An explosive composition including an explosive ingredient and wood normally of high density, which has been distintegrated by the release of high internal pressure.

2. An explosive composition including ammonium nitrate, a normally liquid high explosive and wood normally of high density Which has been disintegrated bythe release of high internal pressure.

3. An explosive composition including ammonium nitrate, sodium nitrate, nitroglycerine and wood normally of high density which has been disintegrated by the release of high internal pressure.

4. An explosive composition including 25%80% of ammonium nitrate, 0%25% of sodium nitrate, about 10% of nitroglycerine and 1%18%'of wood normally of high density which has been disintegrated by the release of high internal pressure.

In testimony of which invention, I have hereunto set my hand, at Wilmington, Del., on this 19th day of J uly, 1927.

LEAVITT N. BENT.