EA040371B1 - SEISMOMETER - Google Patents

Description

The invention relates to measuring technology, in particular to seismometry, and can be used for seismic monitoring.

Known seismometer [1], containing a pendulum with a displacement transducer, a compensating magnetoelectric device, an RC circuit connecting the output of the main amplifier with one output of the coil of the compensating device and an inverting amplifier that connects the output of the main amplifier with the second output of the coil of the compensating magnetoelectric device.

In this seismometer, there is no protection against pendulum withdrawal in the event of an unbalance of the displacement sensor, which does not provide the required accuracy.

The closest technical solution to the proposed one is a three-component borehole seismometer KS-2000BH [2], [3], Geotech Instruments LLC. The seismometer contains in a sealed housing a caging block, a generator, the first, second and third channels for receiving signals, each channel including a spring-loaded pendulum on an elastic support, an integrator, an amplifier, a calibrator, a capacitive displacement sensor connected in series, an amplifier-demodulator, a feedback unit and a magnetoelectric the transducer, and in each channel the pendulum is mechanically connected to the capacitive displacement sensor, to the magnetoelectric transducer and the caging block, the integrator is connected by input to the output of the demodulator amplifier, and the output is connected to the analog output, and the capacitive displacement sensor and the demodulator amplifier are connected to the generator.

The disadvantage of the prototype is the lack of accuracy in measuring seismic vibrations.

The technical result is to increase the accuracy of measuring seismic vibrations.

The technical result is achieved by the fact that the seismometer, containing the body, the pendulum, the first spring, the first elastic support, the generator, the first analog output, the first capacitive displacement sensor, the first amplifier, the first demodulator, the first feedback unit and the first magnetoelectric transducer, connected in series, and the pendulum mechanically connected with the first spring, with the elastic first support, with the first capacitive displacement sensor and with the first magnetoelectric transducer, the first capacitive displacement sensor, the first spring, the elastic first support and the first magnetoelectric transducer are mechanically connected to the housing, and the first capacitive displacement sensor and the first demodulator connected to the generator, additionally contains a series-connected DC filter, the first comparator with an inverse input, the first OR circuit and a timer, the second comparator connected in series with an inverse input and the second OR circuit, as well as the first, second, third th, fourth and fifth inputs, third comparator, fourth comparator, differential amplifier, first two-channel switch connected by inputs to the outputs of the differential amplifier, inverting amplifier connected by input and output, respectively, to the first and second inputs of the differential amplifier, second two-channel switch connected by inputs to the outputs of the differential amplifier, outputs of the first two-channel switch, a micromotor with a drive, a second spring, an elastic second support, a second capacitive displacement sensor connected in series, a second amplifier, a second demodulator, a second feedback unit and a second magnetoelectric converter, as well as a base and a second analog output, moreover, an elastic second support , the second capacitive displacement sensor and the second magnetoelectric transducer are mechanically connected to the body and the base, the second spring is mechanically connected to the body and the micromotor with a drive fixed on the base and connected to the outputs of the second two-channel switch, you the moves of the second OR circuit and the timer are connected to the control inputs of the second and first two-channel switches, respectively, the third comparator is connected to the DC filter by the input, and the output is connected to the second input of the first OR circuit, the fourth comparator is connected to the DC filter by the input, and the output is connected to the second to the input of the second OR circuit, the DC filter is connected to the input of the first demodulator, and the output is connected to the first input of the differential amplifier and to the input of the second comparator, the second capacitive displacement sensor and the second demodulator are connected to the generator, the first, second, fourth and fifth inputs are connected to the inputs control of the first, second, fourth and third comparators, respectively, the third input is connected to the control input of the timer, the first and second analog outputs are connected to the first and second demodulators, respectively, the first, second, third and fourth comparators are controlled by thresholds i, the first and second feedback blocks are made in the form of a filter and an amplifier connected in series, and the timer is made with control over the duration of the output signal.

This embodiment of the seismometer improves the accuracy of measuring seismic vibrations.

The drawing shows a functional diagram of a seismometer. To improve the tracking of connections and blocks, the drawing does not show calibration elements, elements of caging and centering of the pendulum and body.

Accepted designations:

- frame,

- pendulum,

- first spring

- 1 040371 - elastic first support,

- generator,

- the first analog output,

- the first capacitive displacement sensor,

- the first amplifier,

- first demodulator,

- the first block of feedback,

- the first magnetoelectric converter,

- DC filter,

- the first comparator with inverted input,

- the first OR scheme,

- timer,

- second comparator with inverted input,

- the second OR circuit,

- first entry

- second entrance

- the third entrance,

- the fourth entrance,

- the fifth entry,

- the third comparator,

- the fourth comparator,

- differential amplifier,

- the first two-channel key,

- inverting amplifier,

- the second two-channel key,

- micromotor,

- second spring, 31 - elastic second support, 32 - second capacitive displacement sensor, 33 - second amplifier,

- second demodulator,

- the second block of feedback,

- the second magnetoelectric transducer,

- base,

- second analog output.

The seismometer comprises a body 1, a pendulum 2, a first spring 3, an elastic first support 4, a generator 5, a first analog output 6, a first capacitive displacement sensor 7, a first amplifier 8, a first demodulator 9, a first feedback unit 10, and a first magnetoelectric transducer connected in series. 11, and the pendulum 2 is mechanically connected with the first spring 3, with the elastic first support 4, with the first capacitive displacement sensor 7 and with the first magnetoelectric transducer 11, the first capacitive displacement sensor 7, the first spring 3, the elastic first support 4 and the first magnetoelectric transducer 11 mechanically connected to the housing 1, and the first capacitive displacement sensor 7 and the first demodulator 9 are connected to the generator 5, additionally contains a series-connected filter 12 of the constant component, the first comparator 13 with an inverted input, the first OR circuit 14 and timer 15, the second comparator 16 connected in series with an inverted input and a second OR circuit 17, as well as the first, second, third, fourth and fifth inputs 18, 19, 20, 21, 22, the third comparator 23, the fourth comparator 24, the differential amplifier 25, the first two-channel switch 26, connected by the inputs to the outputs of the differential amplifier 25, the inverting amplifier 27, connected by input and output, respectively, to the first and second inputs of the differential amplifier 25, the second two-channel switch 28, connected by inputs to the outputs of the first two-channel switch 26, the micromotor 29 with a drive, the second spring 30, the second elastic support 31, the second capacitive displacement sensor 32 connected in series, the second amplifier 33, the second demodulator 34, the second feedback unit 35 and the second magnetoelectric transducer 36, as well as the base 37 and the second analog output 38, and the elastic second support 31, the second capacitive displacement sensor 32 and the second magnetoelectric transducer 36 are mechanically connected to the housing 1 and base 37, the second spring 30 is mechanically connected to the body som 1 and a micromotor 29 with a drive fixed on the base 37 and connected to the outputs of the second two-channel switch 28, the outputs of the second OR circuit 17 and timer 15 are connected to the control inputs of the second and first two-channel switches 28, 26, respectively, the third comparator 23 is connected to the input to the filter 12, and the output is connected to the second input of the first circuit OR 14, the fourth comparator 24 is connected to the input to the filter 12 of the DC, and the output is connected to the second input of the second circuit OR 17, the filter 12 of the DC is connected to the input to the first demodulator 9, and the output is connected to the first input of the differential amplifier 25 and to the input of the second comparator 16, the second capacitive displacement sensor 32 and the second demodulator 34 are connected to the generator 5, the first, second, fourth and fifth inputs 18, 19, 21, 22 are connected to the inputs control of the first, second, fourth and third comparators 13, 16, 24, 23, respectively, the third input 20 connected with the control input of the timer 15, the first and second analog outputs 6, 38 are connected respectively to the first and second demodulators 9, 34, the first, second, third and fourth comparators 13, 16, 23, 24 are controlled by thresholds, the first and the second feedback blocks 10, 35 are made in the form of a filter and an amplifier connected in series, and the timer 15 is made with control over the duration of the output signal.

The seismometer works as follows.

When seismic influences occur, movement occurs relative to the base 37 of the housing 1 on the second elastic support 31 suspended on the second spring 30, which causes a signal to appear at the output of the second capacitive sensor 32 of the displacement of the housing 1, which is fed to the input of the second amplifier 33, then to the input of the second demodulator 34 is amplified and rectified using the reference signals of the oscillator 5 supplied to the second capacitive displacement sensor 32 and the additional input of the second demodulator 34. The output signal of the second demodulator 34 is fed to the second analog output 38 and through the second feedback unit 35 to the second magnetoelectric converter (MET ) 36, mechanically connected to the body 1. The second MEP 36 implements a negative feedback that forms a mechanical filter that passes to the body 1 and extracts seismic vibrations from the spatial seismic background in the operating frequency range of the seismometer, the direction of which corresponds only to the direction yu swing of the second elastic support 31 and dampens the rest, not matching in frequency or direction, seismic vibrations. The pre-filtered vibrations of the body 1 cause the pendulum 2 to move on the first elastic support 4, suspended on the first spring 3, which causes the appearance of a signal at the output of the first capacitive displacement sensor 7, which is fed to the input of the first amplifier 8, then to the input of the first demodulator 9, is amplified and is rectified using the reference signals of the generator 5 supplied to the first capacitive displacement sensor 7 and the additional input of the first demodulator 9. The output signal of the first demodulator 9 is fed to the input of the filter 12 of the constant component and to the first analog output 6 for further processing.

In addition, the output signal of the first demodulator 9 is fed through the first feedback unit 10 to the first magnetoelectric transducer (MEC) 11, which is mechanically connected to the pendulum 2 and implements negative feedback in the seismometer. When the seismometer is operated in wells, shelters at a constant temperature or on a surface protected by special thermal insulation, the efforts of the first MEP 11 are sufficient to keep the pendulum 2 within the allowable imbalance of the first capacitive displacement sensor 7, causing the appearance of a minimum of a positive or negative constant component of the signal at the output of the first demodulator 9. If it is necessary to operate the seismometer in the field on open areas, large temperature drops cause a displacement of the pendulum 2, an unacceptable imbalance of the first capacitive displacement sensor 7 and the appearance at the first analog output 6 of a positive or negative constant component of the output signal of the first demodulator 9, leading to distortion or absence signal. Usually, in this case, the operator by moving the pendulum 2 manually restores the balance of the first capacitive displacement sensor 7 (it is assumed that the operator monitors the value of the DC component of the signal of the first demodulator 9). In the proposed technical solution, the unbalance of the first capacitive sensor 7 is eliminated as follows. Preliminarily, by applying signals to the first, second, fourth and fifth inputs 18, 19, 21, 22, the response thresholds are set corresponding to the permissible imbalance of the first capacitive sensor 7 for the second and fourth comparators 16, 24 and the response thresholds corresponding to the unacceptable imbalance of the first capacitive sensor 7 for of the first and third comparators 13, 23. When the DC component of the positive or negative signal of the first demodulator 9 appears at the output of the filter 12, which goes beyond the specified thresholds, the second or fourth comparators 16, 24 are triggered, depending on the sign of the DC component of the signal of the first demodulator 9, and through the second OR circuit 17, the second two-channel key 28 is opened. With a further increase in the imbalance of the first capacitive sensor 7, the first or third comparators 13, 23 are triggered, depending on the sign of the constant component of the signal of the first demodulator 9, and timer 15 is started through the first OR circuit 14. Output signal l timer 15 opens the first two-channel key 26, which through the second two-channel key 28 connects the micromotor 29 to the outputs of the differential amplifier 25. and on the other through the inverting amplifier 27. Depending on the sign of the DC component of the signal of the first demodulator 9, the polarity of the voltage at the outputs of the differential amplifier 25, the polarity of the voltage on the micromotor 29 and the direction of rotation of the micromotor 29 change, and the speed of rotation of the micromotor 29 decreases as the value of the DC component decreases.

- 3 040371 signal of the first demodulator 9. As the value of the DC component of the signal of the first demodulator 9 decreases, the first and third comparators 13, 23 remove their output signals, but the timer 15 continues to keep the first two-channel key 26 open. With a further decrease in the value of the constant component of the signal of the first demodulator 9 to an acceptable value, the second and fourth comparators 16, 24 remove their output signals, close the second two-channel switch 28 and stop the micromotor 29 and the movement of the housing 1. After the time specified by the control signal coming from the third input 20, the timer 15 closes the first two-channel switch 26 and turns off the power circuits of the micromotor 29 until the next unacceptable imbalance of the first capacitive sensor 7 appears. Reducing the imbalance of the first capacitive sensor 7 and reducing the level of out-of-band and spatial seismic vibrations by a mechanical filter increases the accuracy of measuring seismic vibrations.

Thus, the claimed result is achieved, and the proposed seismometer improves the accuracy of measuring seismic vibrations.

Information sources.

1. Seismometer (USSR author's certificate No. 577490, MPK7 G01V 1/16, 1976, publ. 10/25/1977) http://patents.su/3-577490-seiismometr.html

2. Broadband Seismometer - Models KS-2000 and KS-2000M, Operation Manual, GEOTECH INSTRUMENTS, LLC, Copyright© 2000-2002, http://www.geoinstr.com/pub/manuals/ks2000m.pdf

3. Broadband Seismometer, Model KS-2000M, Rev. 2, Model KS-2000BH, Datasheets, Reference Data, Geotech instruments, LLC, October 2012, http://www.geoinstr.com/ds-ks2000m.pdf

Claims (1)

CLAIM A seismometer comprising a housing, a pendulum, a first spring, an elastic first support, a generator, a first analog output, a first capacitive displacement sensor connected in series, a first amplifier, a first demodulator, a first feedback unit, and a first magnetoelectric transducer, wherein the pendulum is mechanically connected to the first spring, with an elastic first support, with the first capacitive displacement sensor and with the first magnetoelectric transducer, the first capacitive displacement sensor, the first spring, the elastic first support and the first magnetoelectric transducer are mechanically connected to the housing, and the first capacitive displacement sensor and the first demodulator are connected to the generator, characterized in that , which additionally contains a series-connected DC filter, a first comparator with an inverse input, a first OR circuit and a timer, a second comparator with an inverse input and a second OR circuit connected in series, as well as the first, second, third, fourth and fifth inputs, a third comparator, a fourth comparator, a differential amplifier, the first two-channel switch connected by inputs to the outputs of the differential amplifier, an inverting amplifier connected by input and output, respectively, to the first and second inputs of the differential amplifier, the second two-channel switch, connected by inputs to the outputs of the first two-channel switch, a micromotor with a drive, a second spring, a second elastic support, a second capacitive displacement sensor connected in series, a second amplifier, a second demodulator, a second feedback unit and a second magnetoelectric transducer, as well as a base and a second analog output, wherein the second elastic support, the second capacitive displacement sensor and the second magnetoelectric transducer is mechanically connected to the body and the base, the second spring is mechanically connected to the body and the micromotor with a drive fixed on the base and connected to the outputs of the second two-channel switch, the outputs of the second OR circuit and the timer are connected to the control inputs of the second and first two-channel switches, respectively, the third comparator is connected to the DC filter by the input, and the output is connected to the second input of the first OR circuit, the fourth comparator is connected to the DC filter by the input, and the output is connected to the second input of the second OR circuit , the DC filter is connected to the input to the first demodulator, and the output is connected to the first input of the differential amplifier and to the input of the second comparator, the second capacitive displacement sensor and the second demodulator are connected to the generator, the first, second, fourth and fifth inputs are connected to the control inputs, respectively, of the first, second, fourth and third comparators, the third input is connected to the timer control input, the first and second analog outputs are connected respectively to the first and second demodulators, the first, second, third and fourth comparators are controlled by thresholds, the first and second The feedback loops are made in the form of a filter and an amplifier connected in series, and the timer is made with control over the duration of the output signal. - 4 040371 Eurasian Patent Organization, EAPO Russia, 109012, Moscow, Maly Cherkassky per., 2