SU1377619A1 - Method of contactless measurement of temperature of conducting body surface - Google Patents

Abstract

This invention relates to thermometry. The purpose of the invention is to increase the sensitivity. The method is implemented by the device. In the measurement mode, the part whose temperature is determined is placed in the eddy current transducer 1. A change in the surface temperature of the part will result in a change in the voltage phase at the output of the eddy current transducer 1, which is measured by a phase meter 8. The output voltage of the eddy current transducer 1 is 0.3-0.9 the no-load voltage. Temperature is judged by the phase difference of the voltage. 2 Il. with f

Description

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The invention relates to thermometry and can be used in non-contact measurement of the surface temperature of a conductive body.

The purpose of the invention is to increase the sensitivity.

The method is carried out by placing the body, whose surface temperature is measured, in a uniform electromagnetic field created by an eddy current transducer. The output voltage of the eddy current transducer is determined, and then a compensating voltage is subtracted from it, the value of which is O, 3-0.9 the no-load voltage coinciding in phase with the no-load voltage. The temperature is judged by the phase difference of the voltage.

Figure 1 shows a diagram of the device for implementing the proposed method; Fig. 2 shows the dependence of sensitivity on a generalizing parameter for different values of the compensating voltage.

The device (Fig.) Contains a eddy current transducer 1, a generator 2, a phase shifter 3, an amplifier 4 with an adjustable gain factor, a multiple detector 5, a phase detector. 6, differential amplifier

7 and meter 8 phase

The eddy current transducer, which detects changes in the temperature of the surface of the body, can be made in the form of a known device.

The generator 2, generating harmonic oscillations of constant amplitude and frequency, can also be pea jm30BaH, for example, in the form of a known device.

The phase shifter 3, which changes the phase of the compensating voltage until its voltage equals the phase of the no-load voltage, can be implemented using the example of a known device.

A variable-gain amplifier 4, designed to set a compensating voltage of 0.1-0.9 no-load voltage, can also be implemented using a known device as an example. As a phase detector .6, which finds the phase difference between the compensating and idling voltages and serves to adjust the circuit, as well as a phase meter 8, the output voltage of which

corresponds to the phase shift angle between the reference voltage and the difference, and hence measured temperature, a known device can be used, for example. Amplitude detector 5, which determines the difference between the amplitude values of the no-load voltage and the compensating voltage, can be implemented as follows: voltages from the VTP 1 and amplifier 4 outputs are fed to the inputs of peak detectors that find the maximum voltage amplitudes, and voltage differences from peak detector outputs are on a differential amplifier. For example, a known device can be used as a peak detector.

The essence of the method is as follows.

In the device adjustment mode, the spin converter 1 is outside the part whose temperature is determined, and the voltage at its output is equal to the idle voltage. Using the setting of the phase shifter 3 (adjusted once), the phase matching of the compensating and no-load voltages is achieved, which corresponds to zero at the output of the phase detector 6 and is monitored with a voltmeter. By adjusting the gain of the amplifier 4, a compensating voltage is selected to be 0.3-0.9 the no-load voltage, which is determined by the amplitude detector 5 and is at the output of the voltmeter (voltmeters not shown).

In the measurement mode, the part whose temperature is determined is placed in the eddy current transducer 1. A change in the surface temperature of the part leads to a change in the phase of the voltage drop at the output of the eddy current transducer 1, which is measured by a phase meter 8.

Figure 2 shows the experimentally obtained dependence of sensitivity S (el.grad / ° C) on the generalizing parameter X L1- (5, where R is resistance, with frequency; | U is magnetic permeability; (o is conductivity. Curves in the drawing correspond to the following values of compensating voltage: 1 - 2 - Ux Uy (where U | is the compensating voltage; Uxx is the voltage of the idle cob

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Claims (1)

Claim The method of non-contact measurement of the surface temperature of a conductive body by placing the body in a uniform electromagnetic field created by an eddy current transducer, determining the output voltage of the eddy. hail. ° ^C L