SU1665235A2 - Device for measuring vibrations and displacements - Google Patents

Abstract

The invention relates to a measurement technique and is an improvement of the known device according to an. N1010470. The purpose of the invention — extending the functionality — is achieved by obtaining information on the magnitude of the vibration displacement, its peaks, beats, as well as their variation over time. When changing due to vibration between the end of the measuring coil 2 and the object under study 3, the inductance of the measuring coil 2 changes and, consequently, the oscillation frequency of the generator 1 changes, which leads to a change in the output signals of both frequency detectors 5 and 7. 9 receive the converted signal with a linear characteristic in the area of 0.5 - 3.0 mm. With a gradual increase in the signal of the amplitude of the vibration displacement, the threshold unit is triggered, and on his command the alarm unit. In the event of a spasmodic increase in the swing signal in the vibration displacement signal, this signal is estimated by the front slope, level and frequency in the vibration displacement peak detector 19. In the peak displacement transducer 13, the variable component of the signal is converted to a constant voltage regardless of the direction of movement of the object. 2 hp ff, 4 ill.

Description

1

The invention relates to a measurement technique and is an improvement of the device according to the authors. St. N 1010470.

The purpose of the invention is to increase the reliability and effectiveness of controlling the vibrostate of a turbine unit during its launch and operation, which is achieved by increasing the number of measured and recorded vibratory displacement parameters: the magnitude and peak values of the vibratory displacement, relative static (linear) movements of the shaft, and signaling that the hazardous level of swing and swing of vibration displacement,

FIG. 1 shows a block diagram of the device; in fig. 2 shows a structural transducer of the range of vibration displacement; in fig. 3 is a block diagram of a frequency detector; in fig. 4 - experimental characteristics: curve 1 - eddy current transducer (sensor), curves 2-7 - frequency detector, curve 8 - output characteristic of the device using the described frequency detector at the output of the main device adder.

All characteristics are obtained on a prototype device with an inductance coil with an outer diameter of 12 mm.

A device for measuring vibration and displacement comprises a generator 1, a measuring coil 2 connected to the oscillatory circuit of generator 1 and located on the installation gap a dust near object 3 connected to the output of generator 1 in series connected first limiting amplifier 4 and first frequency detector 5, connected to the output of the generator 1 are connected in series the second amplifier-limiter 6, the second frequency detector 7, the matching stage 8 and the adder 9, the second input connected to the output of the first frequency th detector 5. The output of the adder 9 is connected to the recorder 10, the normalize unit 11 as the displacement signal U (5 (t)), relative to the transducer 12. static movement, to the converter 13 of the peak values of the vibration displacement, to the converter 14 of the amplitude of the vibration displacement and through one of the inputs of the switch 15 to the block 16 of the digital measurement and display. In this case, one output of the converter 12 is relative. The static displacement is not connected to the normalizing block 1 of the relative static displacement signal as ± and (dst), and its second output and the transducer outputs 13 peak values of the vibration displacement and the transducer 14 of the vibration range are connected to the corresponding inputs of the switch 15. In turn, the output

The converter 14 of the range of the vibration displacement is connected simultaneously to the inputs of the detector 18 of the excess range of the vibration displacement, the indicator 19 of the swing of the range of vibration displacement and

0 of the normalizing unit 20 span of the displacement in the form of U (Smi + Sm2). where Smi, Sm2 are the amplitudes of the half-waves of vibration displacements.

The second (pulse) output of block 16

5, the digital measurement and indication is connected to the second pulse inputs of the transducer 14, the span of the vibration displacements, and the detector 19 of the swing of the vibration displacement.

0 The transducer 14 of the vibration displacement contains two half-wavelength, opposite-polarized peak voltmeters 21 and 22. With their analog outputs, they are connected to an inverting and direct

5 inputs of the adder 23, electronic switches 24 and 25 are connected in parallel to the analog outputs of peak voltmeters 21 and 22, the pulse outputs of which are connected to the outlets of the counter 26 of the pulse 0 and the trigger 27. The counting input of the counter of the pulse 26 is its second input and connected to the pulse output of digital measurement and display unit 16. The elevation detector 18 of the displacement vibrope5 contains a threshold unit 28, a setpoint tolerance setting device 29 and an alarm unit 30. The output of the adder 23 is the output of the transducer 14 of the vibration displacement and

0 is connected (Fig. 3) to the input of the signaling device 19 of the swing of the vibration displacement.

The frequency detector 5 or 7 of the device contains a D-flip-flop 31 connected in series, a pulse shaper 32, a sawtooth voltage generator 33, a peak voltmeter 34, and a reference oscillator 35 connected to the second input of the D flip-flop 31.

0 The device operates as follows.

When changing due to vibratory displacement or displacement of the value of the initial installation clearance, the dust between

5, the end of the measuring coil 2 and the object (shaft) 3 under study change the inductance of the measuring coil 2 and, as a result, the oscillation frequency of the generator 1 changes, which leads to a change in the output signals of both

frequency detectors 5 and 7, the inputs of which receive a signal through limiting amplifiers 4 and 6, respectively.

In frequency detectors 5 and 7, a pre-modulated signal is fed to one of the inputs of the D-flip-flop 31. The second input of which receives a signal of a fixed frequency FO from the reference oscillator 35. At the output of the D-flip-flop 31 a differential frequency signal is received, which the driver 32 is converted into a sequence of pulses that trigger a sawtooth voltage generator 33, the peak value of this signal is converted by a peak voltmeter 34 into a signal proportional to the change in pd3HOCT: oiTi frequency. As a result, frequency. ,, 5 and 7, the amhrsgo signal is converted; Ozogo dztch / i a in the signal are proportional to /; green / sv-ie displacement and vibratory displacement / g.

Anzlise egslr, lethal x output characteristics of a ca: tichy detector (Fig. A, more crooked ° -7) shows that by choosing the frequency of the FO f rn generator 35 in the range F0 FJ ,,, you can be: enter its output characteristic

By summing up the frequency detectors 5 and with the corresponding settings and the corresponding transmission coefficient of the matching stage 8 in the adder 9, a transformed signal with a linear characteristic is obtained in the 0.5-3.0 mm section (curve 8, FIG. 4), which contributes to dosgserznost / i control vibrostate and expand the functionality of the device.

The signal from the output of summa 9. contains a constant component, proportional to the installation gap and (5уSt) and static movement ± and (5St), as well as a variable U (5 (t)), proportional to the vibration displacement, is fed to the recorder 10, Advanced This signal is fed through the switch 15 to the digital measurement and display unit 16, as well as to the transducer 14 of the vibration displacement, to the transducer 13 of the peak vibration displacement, to the converter 12 of the relative static displacement and to the normalizing block 11 of the signal roperemescheni providing additional normalized output AC voltage, proportional variable component - of the signal (vibration) for connecting the apparatus vibration spectrum analysis, or for computer processing.

In the transducer 14, the magnitude of the vibratory displacement is variable

the signal arrives at peak heterogeneous voltmeters 21 and 22, which record the magnitude of the peak values (half-waves) of the signal of each vibrational wave, and after summing them in adder 23, a signal is obtained that is proportional to the different MSXV vibrations of one polarity that is output to the normalizing unit 20 span of the vibration displacement, having an output for continuous recording of the span signal, for example, a recording device.

If necessary, the level of the amplitude of the vibration displacement is controlled by the unit 16 for digital measurement and indication by applying this signal to its input through a switch 15

To provide measurement and recording of the -1 level of the vibration displacement with a given accuracy and especially on the lower frequency range of the device. For example, starting from 0.5 Hz, the time constant of the peak voltmeters 21 and 22 is chosen such that the difference between the two maxima of the vibratory displacement signal with a constant amplitude does not exceed the permissible measurement and recording error. The disadvantage of such a vibration displacement transducer is that the day of registration of the decrease in amplitude requires a very large period of time, i.e. big lag. In order to reduce the delay time when registering changes in the level of swing to the sides and decreasing, the outputs of the peak voltmeters 21 and 22 are shunted with electronic keys 24 and 25, respectively, according to the control signal from the trigger 27.

In peak voltmeters 21 and 22, the previous and subsequent amplitudes of the measured signal are continuously compared and, at the moment of transition of the maximum (peak), a pulse is charged by recharging their capacitors (not shown) and impulters to the terminals: - the other inputs of the counter 26 of pulses and trigger 27 which brings them back to their original state and keeps the electronic keys 24 and 25 in the closed state.

When the amplitude of the vibration displacement signal decreases, which is subsequent compared to the previous one (when the span level decreases), peak voltmeters 21 and 22 stop producing pulses for charging capacitors and, therefore, no recirculation pulses will arrive at the pulse counter 26 and trigger 27. Frequency pulses f 1 Hz, coming from the second (pulse) output of digital measurement and display unit 16 to the counting input of pulse counter 26, are recorded by it before filling. If during the counting of N pulses before filling the counter of 26 pulses a tamping pulse does not arrive, a command for trigger% 1 will be issued and at its command electronic switches 24 and 25 will be triggered and accelerated discharge circuits of the capacitors of peak voltmeters | and 22. When the level of the capacitor array decreases to the peak value of the vibration displacement signal, an embossing pulse is produced, by which the pulse counter 26 and the trigger 27 drive to the initial state, and the accelerated discharge circuits of the capacitors open. and keys 24 and 25. When the selection control circuit 2 N rapid discharge of capacitors provides registration varying vibro span beginning at frequencies above 0.25 Hz. If the frequency of the measured signal becomes less than 0.25 Hz, then the pulse counter 26 is filled and a command 27 is issued by the trigger 27 to electronic switches 24 and 25, which open and form the discharge circuits of the peak voltmeters 21 and 22, and measure the span signal vibration displacement is stopped.

With a gradual increase in the signal of vibro-displacement at the output of the transducer 14 of the vibro-displacement and reaching the permissible level and exceeding the set permissible level set in the setting unit 29, the threshold unit 28 is triggered, and at its command and the alarm unit 30, and if necessary, a command can be issued to the protection device .

In the case of occurrence in the signal of the amplitude of the vibration displacement of an abrupt increase in the signal of the amplitude, this signal is estimated by the steepness of the front, in terms of the level and duration in the signaling device 19 of the amplitude of the displacement of the vibratory displacement, and then a signal is issued on the presence of such an increase in the amplitude in the alarm system.

In the peak displacement transducer 13, the variable component of the signal is converted into a constant voltage proportional to the peak value of the object vibration displacement, regardless of the direction of movement of the object. For this purpose, a bipolar peak voltmeter can be used as such a converter. The voltage from the output of the peak value converter 13 through the switch 15 is supplied to the digital measurement and display unit 16.

In the converter 12, the relative static displacement from constant

the signal component, proportional to the gap d, coming from the output of the adder 9, is distinguished with its sign by the magnitude of the change in the constant component cw, proportional to the static displacement (beating).

All changes in this signal, proportional to the static displacement relative to the set zero,

are converted, for example by a full-wave rectifier, transmitted with a sign on the sign through the switch 15 to measure the relative static movement, in addition, these signal changes through

normalizing block 17 is fed to the normalized output signal in the form of ± and (5Ct), proportional to the relative static movement of the object 3, for recording, for example, by recording

device.

Thus, the device allows, in addition to measuring the change in the gap, to measure and record the magnitude of the vibratory displacement of the object and its peak

value, by them, estimate the magnitude and symmetry of oscillations, issue commands to the alarm system, as well as to protect the control object when the level exceeds the allowable range with smooth and

a jump-like change in the magnitude of the vibration displacement, monitor and record changes in the relative static displacement, for example, of the shaft in the bearing of the turbine unit, and, if necessary, analyze the vibration displacement along the harmonic composition for the purpose of vibration diagnostics.

Claims (2)

1. A device for measuring vibration and movement along the ed. St. No. 1010470, which is characterized by the fact that, in order to expand the functionality by obtaining information on the magnitude of the vibration displacement, its peak values, beats, as well as their change over time, it is equipped with a normalizing unit connected to the output of the adder vibration displacement signal, transducer of relative static displacement, peak displacement transducer of vibration displacement by transducer of vibration displacement and a switch connected to output of vibration transceiver of displacement by a vibration displacement transducer of excess vibration range, by a vibration transceiver jump detector and a restraining pulse, and by a reclosing control element of a vibrating displacement amplitude sensor and an overhaul of a vibration displacement peak transducer the normalizing unit of the relative static movement signal connected to the output of the relative static movement converter, and the digital measurement and indication unit connected to the output of the switch, the second input of which is connected to the output of the amplitude converter and the third to the output of the peak converter of the vibration value, and the fourth to the second output of the converter of relative static movement, the output of the digital measurement and indication unit is connected to the second inputs The transducer of the vibration displacement and the signal transducer of the displacement of the vibration displacement. 2. The device according to claim 1, in which, in order to reduce the error in registering the range of vibration, the converter of the range of vibration displacement is made in the form of two different polarized peak voltmeters, the generalized inputs of which are are the first input of the converter of displacement of the vibration displacement, the adder connected inputs respectively to the analog outputs of the peak voltmeters, two electronic switches connected respectively to the analog outputs of the peak voltmeters, and series-connected pulses and a trigger, which connect the inputs to the generalized HNI-puls outputs of the peak voltmeters, the output of the trigger is connected to the supervoltage inputs electronic keys, the counting input of the pulse counter is the second input, and the output of the adder is the output of the vibration displacement transducer, the second inputs of the electronic switches are - naieny to connect to a common bus 3 The device is pop i characterized by the fact that, in order to increase the range of movement being changed, the frequency detectors are made in the form of serially connected reference oscillator, D-flip-flop driver of the pulse generator of the sawtooth current and peak voltmeter, the second input D-flip-flop is the input of the frequency detector, the output of the peak voltmeter is the output of the frequency detector Fiyo.2 / 1 (5) Fig.Z U, WG1MHz 15 ten 10.75 2.5 2.0 15 1.0 ABOUT M00 5 6 §, mm