DE947143C - Method and device for firing explosive cartridges producing pressurized gas - Google Patents

Description

ISSUED AUGUST 9, 1956

15845 IVa J 78 e

Explosive cartridges

The invention relates to an improvement in explosive cartridges known per se, in which the actual explosive charge, consisting of a mixture of an alkali nitrite with an ammonium salt an inorganic acid and small amounts of an alkaline stabilizer in one Flameproof housing is enclosed, in which there is also an external electrical Electricity circuit ignitable detonator to trigger the chemical reaction of the explosive charge is located and which is provided with a blow-out head that extends from the actual housing body an element is separated which yields under a predetermined pressure.

Such known cartridges are particularly used for blasting coal in firedamp and Coal dust-endangered mines applied because the decomposition of the cargo completely without Flame development takes place.

The detonator usually contains a small charge of black powder and it will go off with it known cartridges take a considerable time to decompose after ignition through the entire Has propagated an explosive charge. This ver

delay can be up to ι second and at successive blasts vary somewhat. Although this is only minor in some cases or has no meaning, there is a strong one if serial explosions are to be carried out at the same time Need, the variability of the length of time required for the decomposition to proceed to decrease considerably. It has now been found that the known explosive cartridges in this ίο. Can improve regard if in the detonator a second load of black powder near the other end of the container and also Instant detonators of a certain length and a fire-proof impregnated textile covering is provided, which connects the two ignition charges.

The length of the instant detonator between the two gunpowder charges becomes appropriate sized so that the length of the detonator housing is about the same as that of the main charge. so The igniter according to the invention consists of an electrical ignition head with power supply organs, a primary charge of black powder that is ignited by the electric ignition head, a momentary detonator of a certain length, the textile covering of which is impregnated in a fire-proof manner and which is also ignited by the electric ignition head, and a second black powder charge at the opposite end of the detonator, which is ignited by the instant detonator. The two black powder charges each consist of about 5 to 8 g of granular black powder, and the Burning speed of the second gunpowder charge should preferably be slightly larger than that of the first charge, so that the two Charges have burned down practically at the same time.

In the drawing is an example of an embodiment of an explosive charge according to the invention shown with the novel detonator. Fig. Ι shows a longitudinal section through a Explosive cartridge according to the invention, and

FIG. 2 shows a longitudinal section through the igniter used in the cartridge according to FIG.

In the drawing, 1 represents a steel sleeve of high tensile strength, 2 is a blow head, 3 is a soft-iron disk that yields under a predetermined pressure of the order of 2300 kg / cm ² , 4 is an igniter end with a positive insulated lead wire 5 and a corresponding positive connection 6. 7 is a spacer washer, 8 is a connection for the negative pole of the electric current, 9 is a positive spherical contact piece, 10 is a copper ring provided with a flange, 11 is a fire-proof impregnated cardboard cylinder that holds the first black powder charge 18 contains, which consists of 5.9 g of granular black powder. 12 is a wooden stopper, 13 a copper sleeve, on which a tab 14 is punched out, which is bent inwards and thus forms a hole 15. 16 is an electric ignition head, 17 a plug made of polymerized chloroprene, 19 is a positive lead wire connected to a spring 31, this spring being connected to the positive ball contact 9 of the electric ignition head 16. A negative lead 20 leads from the copper ring 17 to the electrical ignition head 16. 21 is a wooden plug and 22 is the instant igniter, which is made from jute yarn which has been impregnated in a fire-proof manner before the igniter is completed. The end of this instant igniter is pressed into the end of the copper sleeve 13 at 30. 23, 23 'are washers or spacers, 24 denotes a fire-proof, impregnated cardboard container for the second black powder charge 27, which consists of 5.8 g of granular black powder, which has a slightly higher burn rate than the black powder of charge 18. 25 and 26 are wooden stoppers, and 28 denotes the actual explosive charge, which consists of 460 g of a mixture of sodium nitrite, ammonium chloride and magnesium oxide in a weight ratio of 55.25: 43.25: 1.5. When using the explosive charge shown in the drawing, it is inserted into the borehole in the usual way and a power source is connected to the connections 6 and 8. When the current is closed, the ignition head 16 is ignited, which in turn ignites the black powder charge 18 and the instant igniter 22, which at the same time ignites the second black powder charge 27, which burns down somewhat faster. This ■ has the consequence that the two black powder charges 18 and 27 are used up practically at the same time and at the same time initiate the beginning of the decomposition of the main charge at two points that are far apart. When using such a detonator, the time between the closing of the ignition current and the rupture of the washer is reduced to 20 to 50 thousandths of a second, while with the detonators used up to now this time period was of the order of 0.1 to 1 second. This reduction in the delay time makes it possible that the detonators according to the invention can be used to fire a number of shots simultaneously, for example by laying a number of explosive charges of the type shown electrically in series or in parallel and applying a single ignition current . On the other hand, the variability of the period between the closing of the ignition current and the breaking of the washer when using the previously known detonators is such that simultaneous explosions cannot be expected.

Claims (5)

PATENT CLAIMS: i. Process for igniting explosive cartridges which generate pressurized gas and which stabilize a Mix of. an alkali nitrate and an ammonium salt of an inorganic acid and contain an electrically detonable black powder charge, characterized in that; that through the electric ignition head a black powder ignition compound and at the same time a momentary igniter is ignited, which in turn housed one at the other end of the main charge second gunpowder charge ignites. 2. igniter for performing the method according to claim i, characterized in that the ignition charge from a black powder charge that can be ignited by the ignition head at one end the detonator, a second gunpowder charge on the other end of the detonator, and one that connects the two black powder charges and can also be ignited by the fuse head Moment igniter with a fire-proof impregnated textile covering. 3. Detonator according to claim 2, characterized in that the two black powder charges each consist of about 5 to 8 g of granular powder. 4. igniter according to claim 2 and 3, characterized in that the burning rate the second charge is slightly larger than that of the first. 5. igniter according to claim 2 to 4, characterized in that the total length of the two Black powder charges together with the momentary detonator roughly correspond to the length of the main charge generating compressed gas. 1 sheet of drawings © 509 658/474 2.56 (609 575 8.56)