RU2153686C2 - Device for excitation of vibrations - Google Patents

Abstract

FIELD: seismology, in particular, seismic prospecting in those regions, where use of the existing sources of seismic signals is difficult, impossible or undesirable. SUBSTANCE: the signal source is arranged inside the pipe attached to a transmitting plate, it represents a solid-propellant rocket engine with a nozzle unit directed upwards specially modified conformably to seismic prospecting. To reduce the sound waves at engine operation preventing the processing of seismograms, provision is made for a damper installed on the pipe. To ensure the device operation in the pulse and vibration modes and their control in the engine, use is made of charges of ballistite fuel in the form of a bank of thin-arched pipes. The surface modification of the device may be used for excitation of longitudinal and transverse waves in the low-speed zone; the characteristics of radiated monopulse signals are similar to the respective characteristics of the known high-power sources. For the underwater modification of the device provision is made for a cylindrical probe with holes fastened on the cylindrical unit. At operation it may remain in a relatively fixed state. EFFECT: reduced mass, easily and quickly assembled, relatively safe, has no negative influence on environment. 3 dwg

Description

 The invention relates to seismology, in particular to seismic exploration in transition zones of land-water and inaccessible areas of land. It can be successfully used in engineering and geological surveys.

 The prior art devices for the excitation of elastic vibrations containing a solid fuel engine mounted on a transmission pipe and using the energy of impact on it, obtained due to the reactive force caused by the combustion of the charge and the expiration of combustion products through the nozzle.

 A device for exciting elastic vibrations according to SU 1292475 A2, G 01 V 1/104, 1994 is a prototype. It contains a plate with a jet engine rigidly fixed on it having a powder charge. To reduce the level of noise from the sound wave, there is a perforated absorber pipe located coaxially with the engine chamber.

 The device in question is cumbersome. It does not allow to fully realize the energy from the combustion of a charge to excite elastic waves in the soil and significantly reduce the sound effect during engine operation.

 The objective of the invention is to increase the efficiency of the device for exciting vibrations during seismic surveys and geological surveys, comprising a rocket engine with a solid propellant charge inside the chamber and a nozzle block, a sound absorber having a nozzle for the exit of combustion products, and a transmission plate.

 Improving the efficiency is achieved by the fact that the rocket engine is placed inside the pipe mounted on the transmitting plate, at the open end of the pipe there is a sound absorber with a nozzle for the exit of combustion products, the charge is made in the form of tubes with a arch thickness of 0.8-3 mm, fixed in the chamber combustion, from the side opposite the nozzle block.

 In FIG. 1 shows the proposed device, where 1 is the engine, 2 is the stove, 3 is the pipe, 4 is the damper.

 The principle of operation of the device is as follows. When the electric fuse is triggered by an electric pulse, the igniter (smoke powder) begins to burn, followed by the burning of the main charge. The output of the combustion products through the engine nozzle is accompanied by a return to the ground through the engine head and the transfer plate. Accordingly, elastic wave radiation occurs.

 The combustion products from the engine enter first into the pipe, then into the sound absorber, followed by radiation through its nozzle. In the quencher, collisions and mixing of gas flows occur and the combustion of gaseous products that do not have time to react in the engine.

 When using the device, the following technical results are achieved: a decrease in the level of sound waves generated into the atmosphere during engine operation and an increase in return to the ground while simplifying the design of the device.

 The device can operate in pulsed and pulsating modes. Operation time in the first case is up to 16-30 ms, in the second - up to 1-2 s. The released energy and momentum of the force range from 1000-3000 kJ and 600-1400 H • s, respectively.

 In FIG. 2 shows a general view of the engine, section. It contains a charge 1 made of separate elements in the form of tubes rigidly connected to the cover 2, and the body with the nozzle block 3. On the cover there is an electric valve 4, in the nozzle block there is an igniter 5. Between them there is a tube 6. Holes are made in the nozzle block 7 arranged in a circle. On the inside of the camera they are closed with plugs 8.

 After the operation of the electric igniter, the force of the flame is transmitted through the tube to the igniter. Upon reaching a certain threshold pressure in the chamber, the plugs are destroyed and the combustion products exit the engine. The engine design provides a sharper impact into the ground compared to the prototype, which is necessary for seismic studies.

 In FIG. 3 shows an underwater sample of the same engine. It contains a charge 1, a cover 2, a replaceable nozzle block with holes 3, an electric fuse 4, an igniter 5, a tube 6, nozzles 7, a plug 8 and a cable 9.

When it is triggered, the combustion products from the engine chamber fall into the volume between the cylindrical nozzle and the nozzle block. Then the combustion products are bent by 90 ^o due to the presence of peripheral holes in the nozzle and enter the water, exciting seismic signals.

 The possibilities of practical use of devices on the ground and under water are confirmed as a result of experimental and methodological seismic studies.

 They have a small mass, easily assembled during seismic surveys, are simple, reliable and environmentally friendly. Perhaps a quick and massive adjustment of their manufacture.

Claims (1)

 A device for generating elastic vibrations during seismic surveys and geological surveys, comprising a rocket engine with a solid fuel charge inside the combustion chamber and a nozzle block, a sound absorber having a nozzle for the exit of combustion products, a transmission plate, characterized in that the rocket engine is located inside the pipe mounted on the transfer plate, at the open end of the pipe there is a sound absorber with a nozzle for the exit of combustion products, the charge is made in the form of tubes with a thickness of the arch 0.8-3 mm, fastened to the combustion chamber from the side opposite to the nozzle unit.

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