US1963622A - Gelatin dynamite composition - Google Patents

Description

lid

till) Patented June 19, 1934 Ul sr P OFFICE GELATIN DYNAMITE COMPOSITION No Drawing. Application May 19, 1932,

l Serial No, 612,384

10 Claims.

This invention relates, in general, to gelatin dynamltes having improved explosive properties and, more particularly, to gelatin dynamites which exhibit superior sensitiveness and propagating ability after long, periods of storage and with nitroglycerin, nitroglycol, and the like, or-

with mixtures of such nitrated aliphatic alcohols with nitrated aromatic hydrocarbons such as trinitrotolueneor dinitrotoluene, in such proportions as to produce a viscous, plastic, and cohesive mass. Explosive properties such as strength and gaseous products of combustion are modified and adjusted by addition of suitable oxidizing agents and carbonaceous combustibles to the above-mentioned plastic mass.

The usual commercial gelatin dynamites vary in grade strength from 20% to depending on the explosive content. These grades also vary in density, for example, from 1.70 for the low grades to as low as 1.50 for the high grades.

The sensitiveness, or propagating power, of gelatin dynamites varies notably depending on the composition and grade, but also to a marked degree on the density of the explosive; the higher the density, the lower the propagating power, other things being equal. The propagating power of gelatin dynamites decreases with age because of a gradual increase in density, this increase being due to loss of small air bubbles entrapped in the gelatins at the time of manufacture. Furthermore, in deep oil wells and in submarine blasting, where the explosive is subjected to considerable external pressure, the density of the gelatin explosive is increased and its propagating power materially decreased.

It is quite common in the case of relatively deep submarine blasting for the gelatin to be so adversely afiected by the water pressure that it fails to propagate completely, or that a portion of the charge burns, thereby failing to properly blast the rock, thus making it necessary to re-shoot after the dredge has cleaned up the area blasted.

This invention has as an object the production of gelatin dynamites having substantially lower initial densities than have heretofore been practicable. A further object is the production of gelatin dynamites which will maintain 10w densities and satisfactory sensitiveness and propagating power, over long periods of time, under either atmospheric or greater than atmospheric pressures, and dynamites which are superior to gelatins heretofore manufactured for use in oil or gas wells, and in general submarine blasting. Other objects will present themselves as the invention is more fully described hereinafter.

We have found that expanded, and in particular flaked, cereal grains are exceptionally capable of lowering the density of gelatin dynamites. Most low density carbonaceous materials such as wood pulp, vegetable fibres, and the like are highly absorbent, and if an attempt is made to use relatively high percentages of such materials in order to lower the density, the resulting explosives are dry and lacking in plasticity. Them qualities greatly interfere with the cartridging of the gelatin with existing types of machines and impart undesirable physical properties to the explosives. Furthermore the lack of plasticity of such gelatin works against obtaining low density because of the excessive pressure necessary in. order to extrude the gelatin into cartridge form.

We have found that, apparently, because of relatively low absorption value and lack of fibrous character, expanded cereal products can be used to lower the density without adversely afiectlng the plasticity and that higher percentages of such materials can be used than is true of the absorbents now used and yet obtain explosives which are well suited for cartridging on the existing types of machines.

For example, our low density, expanded cereal product may be popped corn, prepared by the 1 application of heat to any of the several varieties of maize commonly known as pop-corn (Zea everta) For the purposes of our invention, it is desirable to reduce the size of the popped kernels and this may be accomplished by any suitable 5- method of grinding. While the ground popped corn, as used, may be of any desired degree of fineness, we prefer to use material the major portion of which passes a S-mesh screen and is re tained on a SO-mesh screen. All of the mateused with satisfaction or, if so desired, the unpopped or partially popped kernels appearing with the product of ordinary popping operations, and the high density material comprising the hull of the corn, may be separated and discarded, in which case a superior product of extremely low density is obtained. The ground popped corn may be used with the normal proportion of moisture remaining after popping or, as is sometimes desirable, may be further dried.

Another means of obtaining our expanded cereal products consists in the process commonly known as pufing, whereby the cereal grains are subjected to high external and internal pressures, with the subsequent sudden release of said pressures. We have found that various grains which lend themselves to the above treatment will accomplish our purpose, such as, for example, wheat, rice, etc. In such treatment, the pressure applied from without (usually steam) permeates the material of the grain and, when the external pressure is released, the pressure within the grain walls causes the explosion or pumng of the grain kernel, thus resulting in a light, fluffy material. Inasmuch as the pufied grains resulting from this treatment remain substantially intact, our purposes are best suited by grinding or crushing the material so as to make it more readily combustible in explosive compositions. We prefer, however, to cut the material to obtain the proper form, in order not to destroy the low density properties existing in the original puffed grain. What has been said previously in regard to the preferred fineness and moisture contents of ground popped corn applies equally in the case of the puffed grains.

In addition to the above, there exist several methods whereby cereals and cereal products such as corn, wheat, rye, rice, starch, hominy grits, and like materials may be converted into the form of low density flakes. The one most commonly used, which will be described in detail hereinafter, is known as the dry process of milling,- as distinguished from the preparation of .starch, which involves what is known as the wet proces.

In the'dry process of milling, as applied generally to maize, the hulls and germs are removed and the grains broken into pieces, cooked by steam or other suitable means, and pressed to form flakes. by first tempering the grains; which consists in softening them by means of a small amount of water, this treatmentrequiring usually from 3 to 4 hours. At the end of the soaking period, live steam is injected into the material. The product is then passed to a degerminator, which breaks up the grain, releasing the germ, the hull, and the softer portion of the'starch which surrounds the germ. In this degerminating process, the horny portion of the maize kernel is usually .cracked or broken into several pieces. It is this horny portion that is most suitable for producing low density flakes. Other starchy portions, of course, may be flaked by themselves or in combination with the horny portion properly reduced to uniform size. The germ of the cereal grain contains a substantial amount of oil, and for this reason, it is desirable to remove this from the horny material before flaking.

The resulting material, which at this point may be termed crude hominy, is then subjected to a cooking process which is intended primarily to slightly soften and preheat the grain before This dry process is accomplishedrial obtained by popping and grinding may be entering the next step in the process. In this cooking process, the temperature of the crude hominy is usually raised to approximately 200 to 250 F. The hot, moist material is then subjected to high pressure, for example by passing through heavy rolls. relatively high temperature and the thus treated grains, in passing through the rolls, are converted into a stifi cohesive flake or sheet.

If the product from the hot rolls is in the form of flakes or sheets, then, in order to convert these flakes or sheets into proper form for our purpose, it is necessary to subject themto a rough grinding process in order to reduce the flakes or sheets to smaller particles suitable for mixing with other explosive ingredients. Flakes of a size suitable for direct use in explosives can be produced, provided the grain particles known as grits are sufficiently small in size. We have found that a suitable materiai is of such a size that a major portion will pass a 6-mesh screen and at the same time be held on a (SO-mesh screen.

There are many variations in the process described in the foregoing; both in the preliminary preparation of the grain and in the handling of the material from the rolls. The essential features of the process, however, lie in passing a treated cereal or cereal product through hot rolls in order to convert it into flakes. There are other processes for producing flaked cereal products. For example, another type of process comprises delivering the moist cereal product to a hot roll provided with a scraper, where the product is dried and gelatinized and removed from the drum by the scraper. Such processes are well known in the art.

While we have found that all materials resulting from the processess describedin the foregoing are substantially lower in density than similar untreated materials, we prefer to use those having These rolls operate at a liiii a density less than 0.3, preferably between 0.1 and Our invention is applicable to all types of gelatinous dynamites and semi-gelatinous amites. The three main classes of the gelatin dynamites are commonly known as straight gelatins, am-

monia gelatins, and permissible gelatins. The straight gelatins range in strength, accordingrto the usual terminology, from 20% to 100%. The

latter is commonly known as blasting gelatin.

The ammonia gelatins usually contain be of either the straight or the ammonia. type,

with the addition of a safety ingredient which permits their safe use in coal mines, where there is danger of explosion from mine gas and coal I dust. The semi-gelatins usually contain a relatively small proportion of gelatinized liquid explosive ingredient and a relatively large proportion of ammonium nitrate, and their densities are generally substantially lower than those of either the straight or ammonia gelatins.

Semigelatins containing no ammonium nitrate, and

having a relatively high density, are also in some use and, while no example of thistype will be given, it is to be understood that such compositions also fall within the scope of our invention.

While our invention is applicable to many different forms Straight Ammonia Permis- Semi- Type gelatin ingredient sible gelatin Nitroglyeerin 4'1. 0 e0. 0 so. a 22. o Dinitrotoluene- 3. 0 3. 5 2. 0 1. 5 Nitrocotton- 1. 3 2. 3 0. 7 0. 2 Sodium mtrate- 36. 1 2. 2 44. 8 9. 0 Ammonium nitrate 24. 0 60. O Ammonium chloride. l5. 0 Expanded cereal product. 9. 0 6. 0 2. 0 6. 9 Starch 2. 7 l. 0 4. 5 Chalk 0. 9 l. 0 1. 0 0. 4

As further illustrative of the value of our invention, we show below a comparison of the formulas and properties of a standard 60% straight gelatin (A) and those of representative 60% straight gelatins (B and C), containing one of our low density cereal products.

A B C Nitroglyoerin 47. 0 47. 0 47. 0 Dinitrotoluene 3. 0 3. 0 3. 0 Nitrocotton 1. 3 1. 3 1. 3 Sodium nitrate 41. 7 36. l 36. 1 Wood pulp (density 0.22) 6. 1 Flaked maize product (density 0.10) (7) g: 2 Calcium carbonate 0. 9 0. 9 0. 9 Density after 1 days storage l. 65 l. 52 1. 47 Sensitivenesu after 1 day's storage--. 12 20 20' Velocity, meters/sec. alter 1 week of mmersion in water at 15 lbs./sq.

.and 10% of these materials as most satisfactory.

It will be understood, of course, that the percentage of ingredients given in the foregoing examples may be varied within wide limits, and that additional ingredients may be introduced without departure from the spirit of our invention. It is also to be understood that we do not limit ourselves to the use of expanded cereal products as the sole combustible material, either high or low density, inasmuch as certain properties of other combustibles may cause their use to be of advantage. We may also use in place of all or part of the nitroglycerin, for example, nitroglycol, nitrated polymerized glycerin, nitrated sugars, nitrated aromatic hydrocarbons, and like compounds.

It is to be understood that we intend to be limited in our invention only as indicated in the following patent claims.

We claim:

1. An explosive composition comprising a gelatinized liquid explosure and an expanded cereal product.

2. An explosive composition comprising a gelatinized liquid explosive and ground popped corn.

3. An explosive composition comprising a gelatinized liquid explosive and a disintegrated puffed cereal grain.

4. An explosive composition comprising a gelatinized liquid explosive and a flaked cereal product.

5. An explosive composition comprising as ingredients a gelatinized liquid explosive and an expanded cereal product, which, when ground to pass a 6-mesh screen, has a density not greater than 0.3.

6. A gelatinous explosive comprising a liquid explosive ingredient, nitrocellulose, and from 0.5 to 15.0% of an expanded cereal product.

7. A gelatinous explosive, characterized by its relatively low density, comprising nitroglycerin, nitrocotton, and from 0.5 to 15.0% of a flaked cereal product.

8. A gelatine dynamite, characterized by its relatively low density, containing as ingredients nitroglycerin, nitrocotton, and a flaked maize product, from which the germ and hull portions have been removed, said flaked product having a densitybetween 0.1 and 0.2.

9. A gelatinous explosive, characterized by its relatively low density, containing as ingredients nitroglycerin, nitrocotton, one or more inorganic oxidizing materials, carbonaceous combustible materials, and a flaked maize product, in the amount of 0.5 to 15.0.

10. An explosive composition comprising a gelatinized liquid explosive and cereal grains having an artificial gelatinized dry outer layer, resistant to theescape of fluid under pressure from the interior of the grain.

NORMAN G. JOHNSON. CLIFFORD A. WOODBURY.