SU1305342A1 - Apparatus for vibroacoustic diagnosis of rock-breaking means - Google Patents

Abstract

The invention relates to the vibroacoustic diagnosis of mountain machines. The purpose of the invention is to increase the accuracy of diagnosing machines with non-stationary load. The device contains a series-connected vibration sensor (VD) 1, a control and processing unit 2 and a wear indication unit 3. Through the band-pass filter 4 and the limiting amplifier 5, VD 1 is connected to the first input of the frequency detector 6. A frequency divider 10 is connected to its second input through the filter 11. The output of the detector 6 through a two-threshold comparator 7 and the logic element And 8 is connected to block 2. A block of 9 time intervals is connected to the second input of the element And 8. The signal taken from HP 1, which is proportional to the level of vibration, goes to block 2. Here it is amplified, detected and processed. The processed signal is recorded only after an enabling impulse is sent from an AND 8 element, which captures the moments of operation of the machine with the same load. This pulse is phased through by comparing, in the detector 6, the frequency of the main harmonic of the engine, extracted by the filter 4, with the synchronous frequency from the divider 10. At the same time, the factor of influence of an unsteady load is completely excluded. 1 il. & (About

Description

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This invention relates to the vibroacoustic diagnosis of mining.

The purpose of the invention is to improve the accuracy of diagnosis of mining machines with non-stationary load.

The drawing shows a block diagram of a device for vibrodiagnostics.

The device contains a vibration sensor 1, a control and processing unit 2, a wear indication block 3, a band-pass filter 4, a limiter amplifier 5, a frequency detector 6, a two-threshold comparator 7, a AND 8 logic element, a time interval block 9, a frequency divider 10, a filter 11 ,

The vibration sensor 1, the control and processing unit 2, the wear indication unit 3 are connected in series. The output of the vibration sensor 1 through a band-pass filter 4 and the amplifier-limiter 5 is connected to the first input of the frequency detector 6, the output of which is connected to the control and processing unit 2 via a two-threshold comparator 7 and logic element 8. The second input of the logic element And 8 is connected to the block 9 time intervals, the second input of the frequency detector 6 is connected through a filter 11 to the divider 10 frequency.

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The device works as follows.

The signal taken from the vibration sensor 1, which is proportional to the level of vibration, enters the control and processing unit 2, where it is amplified, detected and processed. The processed signal is recorded only after an enabling impulse is sent from an AND 8 logic element, which captures the moments of operation of the machine with the same load.

This impulse is generated as follows. Simultaneously from the vibration sensor 1, the signal passes through the band-pass filter 4 and the limiting amplifier 5 to the first input of the frequency detector 6. The band-pass filter 4 selects the fundamental frequency harmonic of the motor, amplifies and provides for comparison with the synchronous frequency to the frequency detector 6. The synchronous frequency is formed from mains frequency divided by the number of pole pairs in frequency 10, then through filter 11, which cuts off the higher harmonics to the second input of frequency detector 6, where the comparison takes place

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frequency of the main harmonic of the engine with a synchronous frequency. At the output of frequency detector 6, a constant value is obtained proportional to the difference of these frequencies. The signal is then fed to a two-threshold comparator 7, which outputs to the input of the logic element AND 8 a signal only when the input voltage is between two levels, which corresponds to the operation of the engine in the interval of certain loads, for example, 0.95-1.05. From a two-threshold comparator, the signal is fed to one input of an AND 8 logic element, and the second input is supplied with a signal from a block of 9 time slots. At the output of the logic element I, when signals appear at both inputs, a pulse appears that triggers the latching and final signal processing circuit in control and processing unit 2.

The control and processing unit 2 contains an analog-to-digital converter, registers, subtractive devices, a comparison device and a register control circuit and operates as follows.

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The vibroacoustic signal from the vibration sensor 1 is fed to the input of an analog-digital converter. Then, the digital signal is entered into the input register at equal intervals of time by the command of the registration control circuit, after which information is copied into the following registers (from each previous one to the next). The signals from the outputs of the registers are fed to the inputs of subtractors, the difference of which is fed to a comparison device, the output of which is fed to the input of the wear indication unit 3.

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The output of the AND gate 8 is input to the registration control circuit. Such an implementation of the control and processing unit 2 allows the calculation of the rate of increase in the wear process of the machine elements at approximately equal time intervals. The values of the vibration signals at the time of measurement depend only on the degree of wear of the machine. The dependence of the vibration signals on the load is absent in this case, since the signals are measured at the moments of equal loads.

This provides the possibility of processing informative vibroacoustic signals, captured at moments with the same fixed load, i.e. the device allows to completely eliminate the influence of non-stationary load during vibro-acoustic diagnostics of mining machines and, thereby, to improve the accuracy of diagnostics.

Claims (1)

Invention Formula A device for vibroacoustic diagnostics of rock-destroying means, containing a vibration sensor, a control and treatment unit, the output of which is connected to a wear indication unit and a block of time intervals, in order to improve the accuracy of diagnostics mining machines with non-stationary load, the device is equipped with a bandpass filter, amplifier-limiter, frequency divider, element I, filter, frequency detector and two-threshold comparator, with the output of the vibration sensor connected to the first input of the control unit and through series-connected band-pass filter and amplifier-limiter to the first input of the frequency detector, the output of which, through a two-threshold comparator, is connected to the first input of the element I, to the second input of which a block of time intervals is connected, you the element stroke AND is connected to the second input of the control and processing unit, and the output of the frequency divider is connected via a filter to the second input of the frequency detector.