SU1728656A2 - X-ray gauge of thickness of rolled products - Google Patents

Abstract

This invention relates to a measurement technique. The aim of the invention is to expand the range of measured thicknesses by correcting the magnitude of the measurement signal by the dependence of the effective linear x-ray attenuation coefficient in the material being monitored on the thickness of the material. The deviation of the thickness of the monitored tape from the optimal one, which is set by the reference sample, causes a change in the supply voltage of the photomultiplier diodes, optically coupled to the sciencillator, which records the x-ray fluxes transmitted through the reference sample and controlled by the tape. The supply voltage is varied so that the resistive divider power supply of the PMT diodes remains constant. The voltage change signal, corrected depending on the thickness of the tape to be monitored, is the measuring signal that is reflected on the recording device. 1 il.

Description

The invention relates to a measuring technique, in particular to X-ray thickness gauges, and can be used to measure the thickness of metal strips on rolling mills, as well as the thickness of paper, cardboard and rubber tapes and is an improvement of the invention according to the authors. St. No. 1458704,

The purpose of the invention is to expand the range of measured thicknesses by introducing a correction of the magnitude of the measuring signal to the dependence of the effective linear attenuation coefficient of x-rays in the material being monitored on the thickness of the material.

The drawing shows a structural diagram of the X-ray thickness gauge rolled.

The X-ray meter contains a working source 1 and a compensating ionizing radiation source 2, a scintillator 3, optically coupled to a photomultiplier tube (PMT) 4, a resistive divider supplying 5 diodes, the output of which is connected to the anode of the PM and the input of amplifier 6, output connected to the unit 7 of the current regulator divider 5 PMT. The output of block 7 is connected to the first input of the high-voltage power source 8 of the PMT and the inputs of the processing and generating unit 9 of the control signal, the outputs of which are connected to the inputs of the registering device 10 and the indicating device 11, as well as to the second input of the high-frequency power source 8, whose output is connected to resistive divider 5 and

h N3 00

Io

ate

ON

Yu

PMC cathode. The processing and shaping control signal unit 9 comprises a maximal signal extraction unit 12 sequentially interconnected, a signal integral value extracting unit 13, a differential comparison signal unit 14, a comparison signal amplifier 15 and a reference voltage block 16, the output of which is connected to the second differential input a comparison signal unit 14, as well as a control signal extraction unit 17, the inputs of the control signal extraction unit 17 being the first and second outputs respectively 9, processing and generating the control signal. In addition, a controlled rolled strip 18 and a standard sample 19 are also shown.

X-ray thickness gauge works as follows.

The X-ray tube radiates alternately in different half-periods of the mains voltage pulses with a frequency of 50 Hz. The scintillus torz receives radiation pulses with the following frequency of 100 Hz, and their intensity follows the law

l lo -G-K

where I is the intensity of the radiation passing through the controlled band;

/, 1 is the effective linear attenuation coefficient;

1o is the radiation intensity in the absence of an absorber;

d is the absorber thickness.

Consequently, a current arises at the anode of the PMT, which is written as Isio-P

Further, the photomultiplier current passed through the amplifier 6 enters the block 7 of the current regulator of the photomultiplier of the photomultiplier, which changes the current of the resistive divider 5 of the photomultiplier diodes, and hence the voltage of the photomultiplier, so that the anode current of the photomultiplier remains constant did not depend on the thickness of the absorber. Then, since the anode

the photomultiplier current and the power supply voltage of the photomultiplier are interconnected

I | xu

1fec - i i

where A is the coefficient of proportionality, and under the condition that the coefficient of proportionality A is identical and the effective attenuation coefficient and, the voltage at the output of block 7 of the current regulator of the PMT divider 5 is proportional to the thickness of the absorber, i.e. u d.

The integral value selection unit 13 automatically selects the signal size at the output of the maximum signal extraction unit 12, i.e., the integral value of the control signal varies depending on the thickness of the rolled stock, and the larger the effective linear attenuation coefficient, the larger the value of the output signal of the pulse duration. The value of the integral signal is compared with the reference voltage, and the signals are automatically aligned in the differential block 14. The signal passing through the amplifier 15 is fed to the power supply 8, through which the signal goes to the PMT divider current regulator 7, which selects output signal proportional to the thickness of the rental. F o rm u l a i z o b e te n i X-ray thickness gauge of rolled products for ed. St. No. 1458704, characterized in that, in order to expand the range of measured thicknesses, it is provided with an integral value selection unit installed in the processing unit and generating a control signal connected between the output of the maximum signal extractor unit and the first differential input unit of the comparison signal unit and performed in the form of an active five-element Chebyshev low-pass filter.

l

Claims (1)

Claim X-ray meter of thickness of hire according to ed. cs. Ns 1458704, characterized in that, in order to expand the range of measured thicknesses, it is equipped with a signal integral value extraction unit installed in the processing and generation of a control signal, connected between the output of the maximum signal extraction unit and the first input of the differential signal comparison unit and made in the form Chebyshev active five-link low-pass filter.