RU2112917C1 - Device for attenuation of underwater explosion shock waves - Google Patents

Abstract

FIELD: safety engineering at underwater explosions. SUBSTANCE: device is made in the form of a screen located around and above an explosive charge. The screen is made of sealed water-proof flexible hoses accommodating cords of elastic material. Freely hanging vertical hoses are arranged around edges of hoses positioned above explosion charge. Vertical hoses are staggered with a density growing in direction of passage of shock waves. Screen is furnished with a float. Screen closely localizes underwater explosion by simple means. EFFECT: enhanced efficiency. 2 cl, 5 dwg

Description

 The invention relates to blasting and is intended to attenuate shock waves (HC) during underwater explosions.

 Known protection of engineering structures and ichthyofauna by a curtain of air bubbles created by sparging of air from perforated pipes.

 Disadvantages of bubble curtains: bubbles rising from the perforated surface of horizontal pipes placed at the bottom of a reservoir form only vertical screens from a gas-liquid medium, which excludes the possibility of protection against shock objects placed above a charge or under an explosive charge; uneven distribution of air bubbles in space and time, as well as the need to use batteries from perforated pipes and a compressor with an energy source.

 The aim of the invention is to increase the efficiency of attenuation of hydrocarbons and comprehensive localization of the focus of an underwater explosion with screens with constant characteristics in space and time created by technically simple means.

 To achieve this goal, a device for attenuating shock waves of an underwater explosion containing a screen is characterized in that the screen is made of sealed waterproof elastic hoses, in which cords of porous elastic material are placed, and consists of horizontal hoses placed above the charge and freely fixed around their perimeter hanging vertical hoses staggered with a density increasing in the direction of passage of the shock wave, while the screen is connected to the float.

 Hoses with porous cords forming a vertical screen are made with negative buoyancy, and those forming a horizontal screen with zero or positive buoyancy.

 In FIG. 1 shows an element for a horizontal screen with zero or positive buoyancy; in FIG. 2 - an element for a vertical screen with negative buoyancy achieved by the weights at the ends of the hoses forming the lower (bottom) part of the vertical screen; in FIG. 3 - a hose with a porous cord in plan; in FIG. 4 is a diagram of the localization of a concentrated charge explosion for seismic exploration of oil and gas offshore; in FIG. 5 is a layout of hoses forming a vertical screen; in the plan, the arrow indicates the direction of hydrocarbon passage through screen elements placed in a checkerboard pattern and with a variable density.

 The following notation is used in the drawings: 1 - a hose made of rubber or rubberized material, 2 - a cord made of microporous rubber, porous rubber or foam, 3 - a tube for sealing the hose, 4 - roller bearings that can be replaced by steel rods without burrs (so as not to break tightness of the hose shell), with lead or cast iron shot and other cargo, 5 — explosive charge, 6 — vertical screen of hoses shown in FIG. 2, 7 is a horizontal screen of a hose with a cord, shown in FIG. 1, 8 - float, 9 - surface for fastening vertical hoses and connecting the vertical screen to the perimeter of the horizontal screen.

 The surface of the fastening 9 can serve as a segment of the conveyor belt with stiffeners made of metal or fiberglass.

 Preparing the device. Cords of porous or microporous elastic rubber or flexible foam (rubber is preferable to being more wear-resistant) with a diameter that allows them to be freely, without difficulty, placed in hoses obtained like hoses in the form of coils, cut at the place of their application into pieces of dimensions required by the depths places of work, the conditions of the explosion and the nature of the protected objects. Plugs for sealing the ends of the hoses can be supplied on adhesive compounds. Ballast for imparting negative buoyancy to vertical screens is created from improvised materials - up to quartz sand, which is poured into the lower end of the hose. Elements of the vertical screen are fixed in the openings of a section of the conveyor belt according to the circuit shown in FIG. 5. Each assembly schematically depicted in FIG. 5 serves as a module. The vertical screens are made up of modules, fixing them along the perimeter of the horizontal screen 7, connecting the elements of FIG. 1. Shields with cables are connected to the float 8. If necessary, fix them with anchors.

 An important advantage of the device is the use of generally available products commercially available from the industry — general-purpose hoses made of rubberized material and elastic porous cords made for gaskets.

 Device action. Cords of porous or microporous rubber, placed in the hoses, exclude compression of the hoses before the passage of the shock wave when the screen is immersed to depths exceeding the compressive strength of the elastic walls of the hose.

 During the interaction of HC with screens along with compression of air inside the hoses, as well as in pores and micropores of elastic cords, accompanied by adiabatic heating of air, additional energy losses of HC occur due to compression deformation of elastic porous cords and mechanical deformation of the hoses when they are compressed with the transition from cylindrical sections to ellipsoidal.

 In addition to energy costs for air compression and elastic deformation of porous cords and walls of hoses, hoses of horizontal and vertical screens act as a series of rods - mechanical dividers of the front of a falling shock wave. Placed in a staggered manner and with a density increasing in the direction of passage of the shock wave, the hoses form a labyrinth system of dividers of the shock wave front.

 In the well-known bubble curtain, the greatest energy loss occurs during dynamic compression of air bubbles. With the complete collapse of the bubbles (their optimal diameter is 2 mm with an outlet diameter of 1 mm), further passage of the shock wave occurs without hindrance.

 Unlike a bubble curtain, a screen made of elastic hoses with elastic porous rods does not lose its ability to absorb HC energy after passing through the screen, which is especially important for localizing a series of explosions in slow and short-blown explosions.

 Bubble curtains create a heterogeneous environment of two water-air phases with a limited volumetric air content, unevenly distributed in time and space.

 Screens from elastic hoses with porous elastic cords create a multiphase medium from materials alternating in the following sequence on the path of the HC: water-elastic wall of the hose-air of the annular gap between the hose and the porous cord — elastic porous cord and air in its micropores — the second wall of the elastic water hose.

 Having passed successively through six materials with different physicomechanical and acoustic properties, hydrocarbons will reduce energy much more intensively than when interacting with a two-phase water-air medium.

 In a screen of hoses with porous rods, the air is evenly distributed in space and constantly in time. By composing screens from modules, it is possible to create a considerable series of screens in depth for attenuation and complete extinction of hydrocarbons, and without limiting the depth and length of the screen with compressors, as is limited in the well-known bubble curtain.

Claims (2)

 1. Device for attenuating shock waves of an underwater explosion, comprising a screen, characterized in that the screen is made of sealed waterproof elastic hoses, in which cords of porous elastic material are placed, and consists of horizontal hoses placed above the charge and vertically freely hanging over their perimeter hoses placed in a checkerboard pattern with a density increasing in the direction of passage of shock waves, while the screen is connected to the float.  2. The device according to claim 1, characterized in that the horizontal hoses with cords are made with zero or positive buoyancy, and the vertical ones with negative buoyancy.

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