RU2163348C1 - Method for localization of underwater burst - Google Patents

Abstract

FIELD: means for absorption or damping of blast waves at underwater bursts of explosives. SUBSTANCE: the method for localization of an underwater burst by a bubble screen rising from the basin bottom to the water surface consists in the fact that chemical gas generators are placed on the basin bottom, actuated and after formation of a bubble screen an explosive charge is blasted. Used as gas generators are charges of artillery and rocket powders, powder and pyrotechnic compounds for pressure or fire-suppression agent accumulators, that are capable of self-sustained burning with liberation of heat and gases. Use may be also made of calcium carbide. EFFECT: enhanced reliability of protection of underwater engineering structures. 3 cl, 2 dwg

Description

 The invention relates to blasting and is intended to localize and attenuate hydraulic shock waves of an underwater explosion.

 Known protection of engineering structures and ichthyofauna with a bubble curtain (PZ) created by bubbling air from perforated pipes [1].

At an air flow of 0.008 m ³ / s, the pressure from the explosion of 0.45 kg of explosive at a distance of 10 m from the charge decreases by a bubble by 70 times [2].

The disadvantage of the prototype [1] is the necessity of using a compressor with an energy source and placing perforated pipes in a strictly horizontal position at the bottom of the reservoir, since when the deviation from the horizontal is more than 3-5 ^o, all air leaves the raised end of the pipe [1, p. 82]. The diameter of the holes should not exceed 1 mm, which limits the flow rate of the supplied air and its volumetric content in the PP, in addition, small holes with soft soil are easily silted.

 The technical task of this invention is to create a PZ technically simple means without the use of a compressor with a power source and battery tubes perforated with small holes.

 The technical result is achieved by the fact that chemical gas generators are placed at the bottom of the reservoir, they are activated and, after the formation of a bubble curtain, an explosive charge is exploded.

 The chemical gas generators use charges of artillery and rocket propellants, powder and pyrotechnic compositions for pressure accumulators or fire extinguishing agents and equivalent materials capable of a self-sustaining combustion reaction with the release of heat and gases, ignite them and create a bubble curtain with gaseous products of combustion.

 Calcium carbide, which releases acetylene during a chemical reaction with water, is also used as a chemical gas generator.

 The scheme of the method is presented in two projections in figures 1 and 2, where the following notation is used: 1 - explosive charges in holes or wells, 2 - chemical gas generators, 3 - gas distributor in the form of a half cylinder with slotted slots, 4 - bubble curtain.

 When creating a closed space around a localized explosion, it is necessary to assemble chemical gas generators on a common basis - for immersion on the ground in one go by simultaneously detaching from the craft or using ship mechanisms and cranes with the exception of diving operations. The assembly of gas-generating charges is lowered together with perforated half-cylinders.

 Gunpowder and pyrotechnic gas generators are ignited by multipoint ignition from a series of electric igniters connected in a single circuit for the almost simultaneous start of their combustion, uniform formation and action of PZs around the perimeter of a localized explosion. Charges with an electric igniter before immersion are surrounded by a waterproofing film, which, after ignition of the charges, burns out and does not interfere with the further evolution of gases.

 When using quick-burning charges from tape, tubular and grained pyroxylin powders, characterized by a large combustion surface, in the center of the powder contour, creating a PZ around a localized explosion, a continuous chain of powder elements with electric igniters is formed to simultaneously ignite the charges along the entire length of the circuit, which together with electric igniters waterproof film material. Close to the resulting assembly of dry pyroxylin powders with electric igniters, powder charges are attached without waterproofing. The latter ignite from dry powder, but will burn in parallel layers in slow motion without ignition covering the entire surface of the powder elements, since this surface is blocked by water. Without the measures outlined, the perforated half-cylinders will be discarded by the gases of quick-burning powders with a highly developed surface for ignition and a bubble curtain will not be created.

 When using slow-burning gunpowder or large-sized pieces of ballistic gunpowder with a limited combustion surface, the above methods of combining dry and submerged powder charges are not required.

 Checkers of ballistic gunpowder with axial channels must be cut along the axis into two halves in order to exclude the scatter of the pieces from the place of their placement on the ground under the influence of a reactive impulse arising from combustion from the side of the cylindrical channel.

 After ignition of the gas-generating charges and the rise of the SC to the surface of the water, which is clearly determined visually by the appearance of a "hump" on its surface, they produce an explosion.

 Slotted slots of half cylinders 3 with a width of 2-4 mm, unlike the prototype, do not clog.

 When creating bubble curtains with acetylene released during the reaction of calcium carbide with water, calcium carbide is used in the form of pressed briquettes or large granules with a complete absence of small particles.

 Calcium carbide is placed on a tape, which, after lowering to the ground, forms a closed loop around a localized explosion, similar to immersion of powder charges, accelerating immersion with ballast to reduce the loss of calcium carbide due to its premature interaction with water. Perforated half cylinders 3 are not used, since acetylene is released evenly from the entire open surface of calcium carbide.

Example 1. The creation of PZ gaseous products of combustion. The width of the PZ at its base at the bottom of the pond is 0.2 m, the volume of one linear meter of PZ of this thickness with a pond depth of 6 and 10 m is 1.2 and 2.0 m ^3, respectively.

The volume of gases during the combustion of pyroxylin powders is 940 l / kg, nitroglycerin - 830 l / kg - at 0 ^o C and 760 mm Hg. With a volumetric content in the PZ of 40% of gases in volumes of 1.2 and 2.0 m ^{3 there} should be 0.48 and 0.8 m ^{3 of} gases. To create 1 line. m of such a curtain will require 0.5 and 0.85 kg of pyroxylin powders or 0.58 and 1.0 kg of nitroglycerin powders - for water depths of 6 and 10 m. The actual gas content in the PP will be higher (or: the consumption of gunpowder may be less), since the combustion temperature of pyroxylin powders reaches 2800 K, and nitroglycerin powders - 3500 K, when rising in water, they will not cool to 0 ^o C, as calculated.

Example 2. The creation of PZ acetylene. 1 kg of calcium carbide releases 0.346 m ^{3 of} acetylene (at 0 ^o C and 760 mm Hg). When the volumetric content in the PZ of 40% acetylene, the consumption of calcium carbide per 1 line. meter PZ with a width of 0.2 m and a depth of 6 and 10 m will be 1.4 and 2.3 kg, respectively. Due to the solubility of acetylene in water, 0.15 g per 100 g of water, the consumption of calcium carbide should be increased by 20% and taking into account losses it will be 1.7 and 2.8 kg per 1 running meter. m PZ with a reservoir depth of 6 and 10 m

 The creation of PZ by acetylene is achieved without the use of any equipment; therefore, support strips with calcium carbide can be placed around the charge at an extremely close distance of two to three charge radii. With a borehole diameter of 100 mm, this distance will be 100-150 mm, which will significantly reduce the consumption of calcium carbide for the entire process of localizing an underwater explosion with its relatively high specific flow rate per meter of bubble curtain.

Sources of information
1. Galkin VV and others. Blasting under water. M .: Nedra, 1987 .-- p. 74-93.

 2. Langefors U., Kilstrom B. Modern technology of explosive rock breaking. M .: Nedra, 1968 .-- p. 271.

Claims (3)

 1. A method of localizing an underwater explosion with a bubble curtain rising from the bottom of the reservoir to the surface of the water, characterized in that chemical gas generators are placed at the bottom of the reservoir, bring them into action and, after the formation of the bubble curtain, detonate an explosive charge.  2. The method according to claim 1, characterized in that at the bottom of the reservoir, charges of artillery and rocket propellants, powder and pyrotechnic compositions for pressure or fire extinguishing agents and equivalent materials capable of a self-sustaining combustion reaction with heat and gases, ignite them and gaseous products of combustion create a bubble curtain.  3. The method according to claim 1, characterized in that at the bottom of the reservoir, calcium carbide is used as a gas generator and a bubble curtain is created by acetylene released during the reaction of calcium carbide with water.

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