SU1339392A1 - Contactless strain-measuring device - Google Patents

Abstract

The invention can be used, for example, in measuring the deformation of rotating turbine blades. The purpose of the invention is to improve the accuracy and noise immunity of the device. The device contains a transmitting part, including a power supply unit 1, N strain gauges 2.1 - 2.N, transmitters 3.1 - 3.N and a receiving part, including an amplifier 5, a master oscillator 6, N blocks 7.T - 7.N registration, N receivers 8.1 - 8.N. Communication between the transmitting and receiving parts is carried out using communication elements 10 and 11. A control block 4 and a switch 9 are inserted into the device. This eliminates errors associated with unequal conditions for the transmission of strain gauge signals and calibration. Close signal and calibration frequencies are provided, and the frequency range occupied by the primary signal and calibration spectrum is also reduced. The description provides examples of the specific implementation of the control unit 4. and the transmitting part of the device. 3 hp f-ly. 3 il. i (L with with

Description

113393922

The invention relates to a control unit 7.1 - 7.N registration. In addition to the measuring technique, in particular, the control unit 4 (Fig. 2), to the means for measuring the deformation, holds the series-connected rotating turbine blades with the help of a band-pass filter 12, an amplitude detector 13, a threshold unit 14 and a stabilizer 15 voltage, the output of which is the output of the control unit 4.

resistance strain gages

The aim of the invention is to improve the accuracy and noise immunity by eliminating errors associated with unequal conditions of transmission by the first input of control unit 4, and of the strain gauge signals and calibration second inputs, respectively, the threshold input of the band-pass filter 12

ki, ensuring close signal and calibration frequencies, as well as reducing the frequency range occupied by the primary signal spectrum and calibration.

Figure 1 shows the structural diagram of the device; Fig. 2 shows the transmitting part of the device; on fig.Z - receiver of the receiving part.

The transmitting part of the contactless strain gauge device (Fig. 1) contains a power supply unit 1, N strain gauges 2.1 - 2.N by the number of measurement channels, N transmitters 3.1 - 3.N, a control unit 4. The receiving part of the contactless strain-gauge device contains an amplifier 5, a master oscillator 6, N blocks 7.1 - 7.N registration, N receivers 8.1 - 8.N, a switch 9 frequency. The communication between the transmitting and receiving parts is carried out using the first 10 and second 11 communication elements.

Each of the strain gauges 2.1-.2.N

The first unit 14 and the voltage regulator 15 are the second input of the control unit 4.

15 In addition, each of the transmitters 3.1-3.N (FIG. 2) contains a series-connected stabilized voltage source 16 and a current stabilizer 17, the output of which is 20 the first input of the transmitter and connected to the first input of the key 18, the second input which is connected to the output of the generator 19 calibration. The input of generator 19 is connected to the third input of key 18, the output of which is connected through serially connected low frequency amplifier 20, frequency modulator 21 is connected to the input of high frequency amplifier 22, the output of which

30 is above the transmitter. The corresponding output of the stabilized voltage source 16 is connected to the fourth input of the key 18 and to the parallel inputs of the amplifier 20.

connected to the corresponding frequency information, frequency modulator 21 and

amplifier 22 high frequency. The input of the stabilized voltage source 16 and the input of the calibration generator 19 are respectively the second 40 and the third inputs of the transmitter.

In addition, each of the receivers 8.1-8, N (Fig. 3) contains a high-frequency amplifier 23 connected in series, a frequency detector 24, 11 of the communication supplying power to the low-pass filter 25 and an amplifier of the transmitting part of the system. The first input is 26 low frequency. Amplifier input 23

the high frequency and low frequency amplifier output 26 are respectively the input and output of the receiver.

The transmitting part of the contactless strain gauge system is placed on a rotating object, for example, in a central drilling of a turbine rotor. The first 10 and second 11 elements of the communication are the home of the second element 11 of the communication. There are two parts of information - the rotor and the main entrance of each of the stator receivers. The rotor part is located 8.1 - 8.N is connected to the output of the first "rotating part of the object and connection element 10 of the connection, and the output is connected to the corresponding a transmission part of the system, and the corresponding input of the corresponding stator is attached to fixed

The input of the corresponding transmitter 3.1 - 3.N. The second inputs of each of the transmitters 3.1-3.N are connected to the output of the power supply unit 1, and the information outputs to the input of the first communication element 10 providing information transfer from the rotating object. The input of the power supply unit 1 is connected to the output of the second element

the control unit 4 is connected to the output of the second communication element 11, the second input is connected to the output of the power supply unit 1, and the output is connected to the control input of each of the transmitters 3.1 - 3.N. The output of the switch 9 frequency through serially connected master oscillator 6 and the amplifier 5 is connected to input 50

the first input of control unit 4, and the second inputs, respectively, of the threshold

The input of bandpass filter 12 is

The first unit 14 and the voltage regulator 15 are the second input of the control unit 4.

In addition, each of the transmitters 3.1-3.N (Fig. 2) contains a series-connected stabilized voltage source 16 and a current stabilizer 17, the output of which is the first input of the transmitter and connected to the first input of the switch 18, the second input of which is connected with an output of calibration generator 19. The input of the generator 19 is connected to the third input of the key 18, the output of which is connected through the serially connected low-frequency amplifier 20, the frequency modulator 21 is connected to the input of the high-frequency amplifier 22, the output of which

is the transmitter's one. The corresponding output of the stabilized voltage source 16 is connected to the fourth input of the key 18 and to the parallel inputs of the amplifier 20.

parts of the object and connected to the receiving part of the system. Rotating transformers can be used as the specified communication elements. The non-contact strain gauge device operates in the following manner.

In the Signal mode using the switch 9 frequency set, for example, the frequency of the master oscillator 6, equal to 10-13 kHz. The voltage of a given frequency is amplified by the amplifier 5 and through the coupling element 11 enters the power supply unit 1, which supplies power to the rectified stabilized voltage of the transmitter part of the system. The voltage from the output of the second coupling element 11 is also fed to the input of the bandpass filter 12 of the control unit 4 However, these frequencies are not included in the bandwidth of the band-pass filter 12, whose tuning frequency is 15 kHz, therefore the voltage at its output is low, the threshold unit 14 does not trigger and does not turn on the voltage stabilizer 15. Therefore the generator

19 calibration does not work, and the key 18 is in the position that provides the connection to the input of the amplifier

20 low frequency outputs of the current stabilizer 17 loaded onto one of the strain gauges 2.1 - 2.N. The vibration damping of the blades with frequencies of 100-5000 Hz is fed to the input of the low-frequency amplifier 20, frequency-modulated by the frequency modulator 21 and amplified by the amplifier 22, is applied to the coupling element 10, on which the signals from all N transmitters are summed.

From the output of the communication element 10, the signals are fed to the inputs of N receivers 8.1-8.N, loaded respectively on N blocks 7.1-7.N registration, the signal of a certain channel is extracted from the common spectrum by the input circuit, amplified by a high-frequency amplifier 10 communications signals are fed to the input of N receivers 8.1-8.N, connected respectively with blocks 7.1-7.N registration. At the same time, the corresponding signal is extracted from the total spectral bandwidth to narrow the bandwidth of the receiver, amplified by amplifier 23, de. emnikov.

Claims (3)

It is detected by the frequency detector 24 of the claims of the invention and passed through the filter 25 low-frequency 1. Non-contact strain gauge and amplifier 26 low h asttoty, a device containing the first and second. ten 15 20 3393924 enters the corresponding registration block 7. In case the frequency switch 9 is in the Calibration position, the frequency of the master oscillator 6 is 15 kHz. In this case, it falls into the passband of the band-pass filter 12. A voltage appears at the output of the amplitude detector 13, the threshold unit 14 triggers, and the voltage regulator 15 turns on. The voltage from its output starts the calibration generator 19 and switches the key 18. In this case, the input of the low-frequency amplifier 20 is applied to the voltage from the output of the calibration generator 19 with a frequency of 400-500 Hz, close to the values of the vibration frequencies on the blades. Further, the calibration signal passes through the same circuits as in the case of passing the useful signal. Thus, the operator can optionally set 25 in the receiving part of the system either of the two modes of the system Signal or Calibration. When the frequency of the master oscillator 6, which differs from 15 kHz to more than 30 by 1 kHz, the output of the voltage control unit 4 is not present and the transmitters 3.1-3.N operate in the signal transmission mode. If the frequency of the master oscillator 6 is 15 ± 1 kHz, a voltage appears at the output of the control unit 4, as a result of which the system switches to the calibration signal transmission mode. The invention makes it possible to increase the accuracy and noise immunity of a contactless strain gauge device in conditions of long-term operation in a turbomachine with varying temperatures (from 20 to 125 ° C), accelerations of 45 to 5000 g, and the presence of an aggressive steam-oil medium. This is achieved due to the complete elimination of errors associated with unequal conditions for the transmission of strain gauge signals and 5Q calibration; providing close signal and calibration frequencies; significant reduction in the frequency range occupied by the primary spectrum of the signal and calibration, which allows significant 40 a secondary communication unit, a transmitting part located on the rotating part of the test object and containing N-sensors, the output of each of the strain gauges is connected to the corresponding information input of the corresponding transmitter, the second inputs of each of the N transmitters are connected to the output of the power supply unit, the outputs N transmitters are combined and connected to the input of the first communication element, the input of the power supply unit is connected to the output of the second communication element, the receiving part, which contains in series connected 1 1 generator and amplifier, you One of which is connected to the input of the second communication element, as well as to the receivers, the information inputs of which are combined and connected to the input of the first communication element, and the output of each of the N receivers is connected to the descent of the corresponding transmission unit, increase accuracy and noise immunity, a control unit is introduced into the transmitting part, and a frequency switch is inserted into the transmitting part, the first input of the control unit is connected to the output of the second communication element, the second input is connected to the output of the power supply unit, and the output to the control unit the course of each of the N transmitters, the output of the frequency switch is connected to the input of the master oscillator. 2. The device according to claim 1, 1 is that the control unit comprises a series-connected band-pass filter, aMajjUTYAHbiiJ detector, threshold unit and voltage regulator, the output of which is the output of the control unit, output the bandpass filter is the input of the control unit, and the inputs of the threshold unit and the voltage stabilizer respectively are the second and 6jroKa control inputs. 3. The device in accordance with claim 1, 1, and 19, which is one of the N transmitters contains a sequence. directly connected source of stabilized voltage and current stabilizer, the output of which is the first input of the transmitter and is connected to the per input of the key, the second input which is connected to the output of the calibration generator, the input of which is connected to the third input of the key, the output of which is -agm ;: ps. successively connected low frequency gel, frequency module) is connected to the input of the amplifier ;;, of its frequency, the output of which is HBJ -. (; tere11, atchik, corresponding to IGI I; yy; I, and the voltage source is connected to Che pc / otsym key care and with corresponding with 1 ::; kkcimi w11vravl-1dmi-1 amplification inputs; / 4b.; jK: on frequencies, frequency code ;; 1 - | ,; p-1 1 amplification and high frequency, I y.o;:. 1 h: rm (stabilized ika   and the input of g} 1sratora kalibo.noBiJi iii-ijL4 cTCH, respectively, the second ipi ibi-iM transmitter inputs. . (, Y (: tr; 11 With Gvo for If 1, and chl u - h: i 10 C e e with the fact that each of K j pi; irMHHf: oB consists of the following sequence: 1: i connect a high-power amplifier (G1; i, a high-frequency detector, a filter of frequencies and a low lacToTH amplifier; and an input of 1 pp high-precision; and a high-low amplifier 4i CT: i bi в: и1ютс respectively, nkho-; UIM and t-receiver input. ag.1 Fig.z