US2074032A - Cartridge for blasting - Google Patents

Description

March 16, 1937.

J. TAYLOR El AL CARTRIDGE FOR BLASTING Filed Feb. 18, 1955 James 722 [or ATTORNEY.

Patented Mar. 16, 1937 UNITED STATES PATENT or ies 2,614,032 7 canrmrocn FOR spasms James Taylor and William Young, Saltcoats,

Scotland, assignors to Imperial Chemical Indust tries Limited, a corporation of Great Britain ApplicationFebi-uary 18, 1935, Serial No. 7,083 In Great Britain February 20, 1934 4 Claims. (01. 102-40) This invention relates to blasting devices of products within the apparatus, the cooling and the kind comprising a charge adapted, on initiaquenching effect of the water persists after the tion, to generate gas, and a pressure resistant venting, and sufllcient is used to fill a substantial metal vessel containing the said charge together portion of the second compartment, so that the 5 with suitable initiating means, the said vessel desirable quenching effect may be obtained. Be- 5 being adapted to release the generated gases at a sides cooling the combustion products the water suiiicient pressure to cause a blasting efiect in has a hydraulic eflect which is effective in blastthe borehole. The gas release means preferably ing. The quantity of the non-detonating e iploconsists of a rupturable and replaceable bursting sive required for the-first compartment W111 in disc, but may also take the form of a. suitably adgeneral be greater than that which is employed 10 justed valve. as the heating medium when an exothermic gas More particularly the invention relates to an producing liquid is employed, but can best be de improved device of the above character which is termined by trial and error, it being advantaapplicable for use in fiery mines or in mines geous to use at least from 12-25% more than the 15 where a large yield of lump coal is desired. minimum amount. 15

In the particular forms of device with which The device is charged and assembled shortly the present invention is concerned there are probefore use and is loaded into the borehole as a vided two rigid containers which are screwed towhole. The two containers and the cap are made gether before use, one of these containers being strong enough to withstand the iorce of the excharged with a non-detonating explosive and plosion and can be recovered and used repeatedly. 2 being provided with a means for igniting it, the One form of our invention is illustrated in the other container being wholly or partly filled with attached drawing, which represents a central aliquid, the two being separated, when the device longitudinal section of the device. is assembled, by a water-proof disc adapted to A rigid steel container I is closed at one end withstand only very low pressures. A device of by a screw-in plug 2 through which passes an 25 this character is described in the specification of insulated electrode 3 which is so constructed as our pending application Serial No. 712,051. to be gas-tight at pressures up to 25 tons per sq.

According to the above specification there was in. Near the other end of the container is proemployed a quantity of a solution or suspension vided a shoulder 6 against which rests a fibre of a quantity of exothermically reacting gas waterproof disc 5. The disc is held firmlyun 30 evolving material together with heating means place by means of a second container 4 which inadequate in themselves to determine the ventscrews into the open end of the first container. ing of the contents from the device, a charge of The disc serves to close the passage between cona non-detonating explosive as heating means tainers l and 4, but is not strong enough to with- 5 being included in one compartment of a. device of stand any but very low pressures- The Other 5 the kind described, and a charge of a solution end of container 4 is provided with a shoulder 1 or suspension of the exothermically reacting gas and a steel bursting disc 8. A fibre sealing washevolving material being included in the other or IE, is interposed between the disc 8 and the compartment. The quantities of the charges shoulder I. The bursting disc is held firmly in were so arranged that the venting of the appaposition by means of the hollow screw-in cap 9 40 ratus as a whole would not take place when the which is pierced by one or more channels in liquid was replaced by an equal quantity of water. through which the blasting force is directed and It is also possible, however, to achieve a blast distributed. The terminals i3 and it of the elecadvantageously in an apparatus of the character trodes are covered by a screwed on cap l5 prodescribed, without the use of the exothermically vided with an aperture l6 for the insulated leads 45 gas evolving liquid, and according to the present from the exploder or other suitable source of invention water is used in an apparatus of the current. above character for the purpose of quenching The container I is loaded with a charge of a and/or cooling the products of combustion of non-detonating explosive which is ignited by the non-detonating explosive contained in the -mea.ns of an appropriate fuse ll, one lead of 50 first compartment provided the charge of nonwhich is connected to the electrode 3 and the cirdetonating explosive in the first compartment is cuit is completed via the metal container by the suflicient to cause venting as the result of preselectrode ll. As suitable explosives we may mensure built up in the free space available for its tion blackpowder, N. D. cordite flake, and mixcombustion. Besides cooling the combustion tures containing charcoal and ammonium ni- 55 trate. If desired this may be made up in cartridge form with or without the igniter. Container t is wholly or partly filled with water.

When the device is fired, the charge l8 in container 1 begins to burn, bursting the disc 5. The combustion products are then cooled progressively by the water IS in container 4 and by expansion, so that by the time the bursting disc 8 has burst and the water has been ejected they are incapable of igniting firedamp or coal dust. The duration and degree 01 cooling may be regulated by choosing a powder with a suitable rate of burning and by selecting a sealing disc adapted to burst at an appropriate pressure. Besides cooling the combustion products the water exerts a hydraulic effect which is effective in blasting. The cartridge is loaded into the borehole with the cap 9 inmost. If desired it may be tamped.

The weight of the charge will depend on the size of the device used. A device of the example illustrated, with a powder chamber of 230 c.c. capacity, is loaded with 90 gm. cordite in flake form and a 5 grain powder fuse connected electrically' to the electrodes. The water chamber of capacity 440 0.0. is completely filled with water and the cartridge is screwed up. The cartridge so prepared will not ignite to a 9% methane-air mixture when fired in it.

We claim:

1. A blasting device comprising a pressure-resistant container, means for venting the gases radially from the container at a predetermined and considerable pressure, means for initiating the decomposition of a non-detonating. gas -genl crating explosive composition contained therein, and a pressure-responsive waterproof means separating said container into two compartments, the compartment adjacent to said venting means containing water in an amount suflicient to cool 1 and quench the products of combustion oisaid explosive charge, and the other said compartment containing a non-detonating explosive, said means for initiating the decomposition oi said explosive and a volume of compressible gas 1 suflicient to cause the commingling between the products of combustion of the explosive and the water in the adjacent compartment before said venting means is actuated.

2. The blasting device of claim Lin which 2 said non-detonating explosive comprises black powder.

3. The blasting device of claim 1, in which said non-detonating explosive comprises ammonium nitrate and charcoal. 2i

4. The blasting device of claim 1, in which said non-'detonating explosive comprises cordlte.

JAMES TAYLOR. WILHAM YOUNG.

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