SU951081A1 - Radio isotope level indicator - Google Patents

Description

This invention relates to radioisotope instrumentation and is intended to measure the level of a substance in a vessel.

Radioisotope level gauges are known, consisting of a radiation source placed in a float, a detector and an electronic unit. The principle of operation of these devices is based on the detection of radiation, which changes with a change in the distance between the stationary detector and moving together with the level of the substance - the float Cl3.

The disadvantages of these devices include a limited measuring range, a high activity of the radiation source with a large measuring range, the dependence of the instrument readings on the stability of the detection channel, and non-linearity of the scale over the entire measuring range.

The closest to the essence of the offer is a radioisotope level gauge designed to monitor the level of the substance in the vessel. The level gauge consists of a radiation source mounted on the float, detectors mounted on the outer wall of the vessel and

an electronic unit containing drivers and an output stage. The accuracy of the level measurement depends on the number of detectors (as the number of detectors increases, the number of individual levels at which the measurement is made increases, which, with a fixed vessel height, increases the measurement accuracy) and their geometrical dimensions (the smaller the transverse dimensions of the detector, the more accurate determine the estimated location of its location on the vessel wall). The level gauge has an unlimited measuring range of 2.

The disadvantage of this level gauge is the low level measurement accuracy with a limited number of detectors.

The purpose of the invention is to improve the accuracy of level measurement.

The goal is achieved by the fact that in a radioisotope level gauge containing a radiation source with a collimator mounted on the float, detectors located evenly along the height of the level gauge, an electronic unit including shapers connected to the outputs of the corresponding detectors and an output stage, the detectors are completed arranged parallel to the axis of movement of the radiation source and displaced relative to each other by an amount corresponding to the measurement accuracy, and the electronic unit is designed as a divider frequencies equal to the number of detectors, a memory register, a decoder, a converter, a generator, a binary counter, and a delay circuit, the outputs of the formers are connected through frequency dividers to the corresponding bits of the memory register, the outputs of which are connected via a decoder with the converter inputs, the converter output is connected to the output stage input, the generator output is binary connected to the control register input of the memory register, which through the delay circuit is connected to the installation inputs Itel frequency. The drawing shows a structural diagram of the proposed level gauge. The level meter contains a radiation source with a collimator 1, mounted on the float, detectors 2, an electronic unit 3 consisting of frequency formers of frequency dividers 5, memory register b, decoder 7, converter 8, output stage 9, frequency generator 10, binary counter 11 and delay circuits 12. The outputs of the detectors 2 are connected to the inputs of the drivers 4 that are included in the electronic unit 3. The outputs of the drivers through frequency dividers 5 are connected to the corresponding bits of the memory register b, the outputs of which are through the decoder 7, zovatel 8 are connected to the output stage 9, a constant frequency generator 10 via the binary counter 11 is connected to a control input of the register and the memory 6 via the delay circuit 12 - by setting the frequency dividers 5. inputs / rovnemer operates as follows. The radiation source with collimator 1 emits a flux of jp radiation into a small solid angle depending on the required level measurement accuracy. The flux of 1p radiation is sensed by the detectors 2, the output of which is an output signal whose value is proportional to the intensity of the radiation detected by this detector. These signals are fed to the input of the electronic unit 5, which converts them into the desired output signal. Since the detectors 2 are located in two or several rows and each detector is shifted relative to the other, then at a certain position of the radiation source 1, i.e. at a given level of a substance in a vessel, one or several detectors 2 enter the beam of radiation. Therefore, the outputs of one or several detectors have a large output signal, and the outputs of the remaining detectors are 2 ma. These signals in the electronic unit 3 are used to determine the level of the substance in the vessel and obtain the required output signal. The output signals from detectors 2 to :: blunt to the drivers 4 and from them to you; soda to frequency dividers 5. SigHa .i is high if the detector enters the radiation beam of source 1 and low if the detector is outside the beam radiation. At the specified location of the detectors 2, a high signal level comes from one or more detectors. After the end of the measurement interval, the signal from the outputs of frequency dividers 5 is written to memory register b by a signal from binary counter 11, which is fed to the control input of memory register b. After the delay in the delay circuit 12, the same signal sets the frequency dividers 5 to the initial state, then the next measurement interval begins, the output signals from the bits of the memory register b are sent to the decoder 7, where they are converted into a position code, i.e. the signal on one of the outputs of the decoder 7 has one logical level, for example 1, and on the others, another logical level, for example O. The output at which the signal (1) appears is determined by the position of the level of the substance in the vessel. The output signal from the decoder 7 is fed to the converter 8, in which the input-to-transformation is carried out. go position code to desired output: binary code, constant voltage, etc. The signal from converter 8 is provided to output stage 9. Example. Detectors 2 are located in three rows, their length is 2 RE and each detector is shifted relative to the other by the value of d, i.e. to one third of its length, with three detectors distinguishing between five sections of width U. In the first area, only the first detector enters the radiation beam, the first and second detectors fall on II, all three detectors on III, the second and third detectors on IV, only the third detector on V. The following five sections of D are overlapped by the other three detectors. Pos. Since each time the memory register register B records a signal from one of the detectors 2, then the code recorded in memory register b is on section I 100-0, on section II it is 110-0, on section III it is 1110-0 and etc. In the proposed radonoisotope level gauge, detectors are 2 extended, i.e. their length is greater than the measurement error two or more times. Geiger-Müller SBM-18, SBM-20 and others can be taken as such detectors. You can also use other detectors that meet the above requirement. The digital part of the proposed device can be performed on integrated circuits of the 133, 134, 155, 164 series and so on. Frequency dividers 5 and binary counters 11 jMoryT can be performed by any known scheme. The delay circuit 12 is a standby multivibrator. Memory register 6 can be built on triggers. The decoder 7 can be executed on the IS-NOT circuits, whose inputs are connected to the corresponding bits of memory register 6, the number of inputs of the IS-NOT circuits is determined by the number of detectors 2 that fall into the radiation beam at a given level of matter in the vessel, B in the considered example, when three rows of shifted detectors 2 were used, it is necessary to have three-input AND-NOT schemes. Direct and inverse outputs of memory register 6 bits are connected to the inputs of the AND-NIC circuits, for example for the second section it is necessary to connect the direct output of the first and second bits, as well as the inverse output of the third bit. At the output of the decoder 7, a position code is obtained. Such a code can be inconvenient for use, therefore, a converter is included in the device that transforms the input code into the required output signal: constant voltage, binary code, binary-decimal code. Depending on the desired output signal, the converter 8 is executed in the appropriate manner. For example, when the output signal is a constant voltage, converter 8 consists of an encoder that converts the position code into a binary-decimal and digital-to-analog converter. The circuits of these devices are known. The invention of a radioisotope level gauge containing a collimator radiation source reinforced with a float, detectors located at the height of the level gauge, drivers connected to the Outputs of the respective detectors, and an electronic unit, characterized in that, in order to improve the level measurement accuracy, the detectors are long and arranged is parallel to the axis of movement of the radiation source and offset relative to each other by an amount corresponding to the measurement accuracy, and the electronic unit is designed as frequency in an amount equal to the number of detectors, memory register, lender, converter, oscillator, binary counter and delay circuit, the outputs of the drivers are connected via frequency dividers to the corresponding bits of the memory register, the outputs of which are connected via the decoder to the converter inputs , the output of the converter is connected to the input of the output stage, the generator output is connected via a binary counter to the control input of the memory register, which through the delay circuit is connected to the inputs of anovki frequency dividers. Sources of information taken into account during the examination 1. Rudanovsky A.D., Krez D.P. Radioisotope methods for monitoring and measuring levels, M., Atomizdat, 1967, p. 19. 2. Pugachev A.V., Sakharov E.V. A Handbook of Radioisotope Automatics. M., Energie, 1974, p. 174 (prototype).

Claims (1)

Claim A radioisotope level gauge containing a radiation source with a collimator mounted on a float, detectors located along the height of the level gauge, shapers connected to the outputs of the respective detectors, and an electronic unit, characterized in that, in order to improve the accuracy of level measurement, the detectors are long and are arranged parallel to the axis of movement of the radiation source and are offset relative to each other by an amount corresponding to the accuracy of the measurement, and the electronic unit is made in the form of frequency dividers s are in an amount equal to the number of detectors, a memory register, an encoder, a converter, a generator, a binary counter and a delay circuit, and the outputs of the formers through frequency dividers are connected to the corresponding bits of the memory register, the outputs of which through a decoder are connected to the inputs of the converter, the output of the converter is connected to the input output stage, the output of the generator through a binary counter is connected to the control input of the memory register, which through a delay circuit is connected to the inputs of the installation of dividers stota.