SU387260A1 - ac ^: UNION li '^ ~ imm-wm ^ E, m - Google Patents

Description

RADIO ISIZABLE COMPENSATION DENSITY

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The invention relates to the field of measuring the density of liquid media using radioisotope density meters.

Known densitometer on the author. St. No. 160352, containing two radiation sources, a fluid-controlled cuvette, a reference movable wedge and a receiving device made in the form of an asynchronous rotor with circumferential radiation receivers connected to the input of the signal comparison unit through a switch and integrating whose Q).

In the known densitometer, the contacts of a polarized relay, used as an input element of the comparator unit, are worn out and misaligned during operation, which leads to a simultaneous short circuit within a certain period of time of both relay contacts and, consequently, to an additional error of the device due to equalization voltage on the integrating cells in the period of simultaneous closing of contacts.

The purpose of the invention is to increase the stability of the device.

This is achieved by connecting a valve to the circuit between the integrating cell and the corresponding input of the comparison unit.

The drawing shows the block diagram of the proposed densitometer.

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The densitometer contains a working radiation source 1, a cuvette 2 with a controlled fluid, a reference movable wedge 3, a compensation radiation source 4, a receiving device 5 made in the form of an asynchronous rotor with circumferential radiation meters counters 6 connected to the input of the comparison unit 7 as which, for example, a polarized relay or a vibration converter is used, through the switch 8 and the integrating cell 9. A circuit between the integrating cell 9 and the corresponding input of the comparison unit 7 includes n gate 10. The output of block 7 is compared with the amplifier 11, the load of which is the winding of the reversing motor 12. The shaft of the motor 12 is connected to the reference moving wedge 3 via a reducer.

The effect of the radioisotope density meter is based on the dependence of the degree of absorption of gamma radiation on the density of the absorbing medium. Gamma-radiation from working source 1 passes through a cuvette with a measured track and gets to counters 6. With

the switch 8, the signal is removed only by the three counters. The voltage on the integrating cell 9 of the compensation channel is proportional to the number of gamma-quantoB that fall on these counters per unit time.

Constant voltage with integrating

3

The main channel cells 9 are periodically compared with the voltage of the compensation channel by the comparator unit 7. When these voltages are equal, the difference AC signal at the output of the comparison unit 7 is zero.

When the density of the measured medium changes, the number of gamma quanta falling on the main channel counters 6 changes, and consequently, the voltage on the integrating cell 9 of the main channel changes, which leads to the appearance of a differential variable signal at the output of the comparison unit 7, which is amplified amplifier 11 k is applied to the winding of the reversing motor 12. The engine turns the reference wedge 3 until (4,

the absorption of gamma radiation in it will not become equal to the absorption of the measured medium. The angle of rotation of the wedge is proportional to the change in the density of the medium.

In the case of a misalignment of the comparison unit 7, the valves 10 exclude the flow of the equalizing current by the integrating cells 9 of the main and compensation channels.

Subject invention

Radio isotope Komi-sensational densitometer on the author. St. No. 160352, characterized in that, in order to increase the reliability of the instrument, a valve is connected to the circuit between the integrating cell and the corresponding input of the comparison unit.

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