SU1267318A1 - Electrodynamic geophone - Google Patents

Abstract

The invention relates to the field of registration of seismic vibrations and may find application in the study of elastic waves of earthquakes and powerful industrial explosions. The purpose of the invention is to improve the quality of recording of seismic signals and the expansion of the amplitude-frequency range. The goal is achieved by performing an inertial mass in the form of a capsule with a magnet and additional weight placed in a thin-walled cylinder that holds a transducer coil with a variable number of turns of Cu along the longitudinal axis of the cylinder x according to the O / C x ratio. This ensures the constancy of the coefficient of the electromechanical coupling of the converter when the capsule φ is displaced along the cylinder when the natural frequency of the seismic receiver is adjusted (L to change the mass of the capsule and the strength of the magnetic field of its suspension. G Il.

Description

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The invention relates to the registration of seismic vibrations and may find application in the study of elastic waves of earthquakes and powerful industrial explosions.

The purpose of the invention is to improve the quality of recording seismic signals and the expansion of the amplitude-frequency range.

The drawing shows a diagram of a geophone.

In the housing 1, made of a non-magnetic material, is placed a thin-walled cylinder 2, on which the transducer coil 3 is rigidly fixed. In the field of the constant reference magnet 4, an inert mass is made in the form of a capsule 5, inside which is fixed rigidly movable magnet 6 and additional weight 7. The contact of the capsule with the walls of the cylinder is sliding, so the capsule and the cylinder are made of a material with a low coefficient of training for example, fluoroplastic. At the upper base of the cylinder there is an astasing rod 8, which by means of the screw 9 is moved along the axis of the cylinder. Capsule restraints are designed as tides 10.

i

The device works as follows.

in a way.

At the moment of arrival of the elastic wave, the capsule 5 is displaced in the direction of the reference magnet 4. As a result, the flux of the magnetic induction changes, the coils of the transducer 3 are spinning, and an emf is generated at the output of the seismic receiver that is proportional to the number of turns of W in the coil section at a distance X from the reference the magnet, the area S of the same cross section of the coil, the flux density of induction B and the speed of displacement of the capsule dx / dt

dUBS dx

E

dx dt

A change in the number and area of the turns of the coil of the converter 3 is inversely proportional to the plane of the flux of the magnetic induction, which ensures the constancy of the coefficient of electromechanical communication (KEMS)

duBS d -: j- const dx dx

673182

and the EMF at the output of the seismic receiver is only dependent on the speed of the capsule.

The magnetic flux through any turn 5 of the converter coil is proportional to the area of this turn S and the magnitude of the magnetic induction B

P SB.

At the distance X, and X between the magnets have

2M

2M

at

v

x, 1

From the condition, it follows that the number of turns of the converter coil varies according to the law

 J

where is the number of turns at a distance

HD from the reference magnet; to; - the same, at distance X; .

Changing the sensitivity and period of natural oscillations of the seismic receiver is carried out by selecting the weight of the additional load 7 and moving the astasizing rod 8 with the screw 9. produced during the assembly of the geophone.

The proposed geophone can be used to record a wide range of wavelengths, while still achieving the best ratio of the decay time to the sensitivity of the instrument. Its much faster attenuation while retaining the same sensitivity allows us to increase the efficiency of modern re-equipment of seismic surveys based on cipher stations. The high resolution of the instrument is used in ore seismic surveys for differentiation of slightly reflecting depth horizons. The weak sensitivity to microseismic vibrations provides the possibility of its use for seismic additional exploration of industrial mining and oil-bearing areas.

55 Formula of invention

Electrodynamic seismic receiver containing inert mass with under

Claims (1)

Claim 1267318 4 the capsule is placed inside a thin-walled cylinder on which the converter coil is rigidly fixed, the number of turns of which increases $ along its axis according to the ratio where & ₀ is the number of turns at a distance IQ X ₀ from the reference magnet; W; - the same, at a distance of X ;. a moving magnet, a support magnet, an astasizing rod, rigidly fixed to the housing, a converter coil, characterized in that, in order to improve the quality of registration of seismic signals and expand the amplitude-frequency range, the inertial mass is made in the form of a capsule inside which a movable magnet is fixed , and at the bottom there is an additional load, at