SU1534323A1 - Method of determining consumption of gas and liquid flows - Google Patents

Abstract

The invention relates to a measuring technique and can be used to measure the flow rate in industries that use gas or vapor-liquid flows in technological processes. The aim of the invention is to simplify the measurement process. The density converter 1 converts the density fluctuations of the gas-liquid mixture into an electrical signal by scanning the mixture with a stream of gamma rays from the radiation source 2 and registering them with the detecting unit 3. Since the average length of the liquid plug in flows with a scraper structure does not depend on the regime parameters of the flow, but only on the diameter of the pipeline, the average duration of the passage of the liquid plug characterizes the velocity of the gas-liquid flow. The number of pulses corresponding to the number of liquid plugs allocated by the threshold device 5 is counted by counter 6, the signal duration is determined by counter 9. The signal at the output of divider 10 corresponds to the average duration of the passage of the liquid plug. 1 il.

Description

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On the other hand, the average length of the fluid tube does not depend on the regime parameters of the flow, but only on the diameter of the pipeline; the average duration of the passage time of the fluid tube characterizes the velocity of the gas-liquid flow. The number of pulses, according to the Invention, relates to a measurement technique, in particular, to methods and means of measuring flow, and can be used in power engineering, hydraulic engineering, petroleum, chemical and other industries that use gas or vapor-liquid flows in technological processes. 2

The purpose of the invention is to simplify the measurement process.

The essence of the method is as follows.

The gas-liquid flow with a projectile structure is an alternation of liquid plugs and gas projectiles, and this structure is stable in a wide range of para-3 meter flow.

It has been established that the average length of the fluid block does not depend on the regime parameters of the flow and in the range of variation of the true volumetric gas content from 0.1 to 0.75 fractions is determined only by the diameter of the pipeline. It was found that, up to a static spread, the ratio

Tnp / D 10, where 1 „is the average fluid length

traffic jams;

D is the internal diameter of the pipeline.

The indicated property of the constant length of the liquid tube in a wide range of variations in the conditions of air and steam flows makes it possible to determine the volume flow rate by the length of time the liquid tube passes through a controlled flow section, and the change in the gas content in the flow only changes the length of the gas projectiles during the passage of the liquid tube controlled cross-section.

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The number of liquid plugs allocated by the threshold device 5 is counted by counter 6, the duration of the signal is determined by counter 9. The output signal of the divider 10 corresponds to the average duration of the passage of the liquid plug. 1 il.

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The drawing shows a device illustrating the proposed method.

The device contains a primary density converter for gas-liquid mixture 1, for example, radioisotope, comprising a radiation source unit 2 and a detecting unit 3 located on opposite sides of the pipeline 4. The output of the detecting unit through threshold devices 5 is connected to a counter of 6 pulses and the first input of the And 7 circuit , the second input of which is connected to the output of the reference frequency generator 8. The output of the circuit And 7 is connected to the counter 9 pulses. The outputs of the counters 6 and 9 pulses are connected to the inputs of the separating device 10.

The device works as follows.

The primary density converter 1 converts the density fluctuations of the gas-liquid mixture into an electrical signal by scanning the mixture with a flux of gamma rays from the radiation source unit 2 and detecting the gamma rays passed through the controlled medium using the detection unit 3. From the output of the detecting unit, a signal, functionally related to the density of the mixture, enters the input of the threshold device 5, where its part is allocated corresponding to the passage time of the liquid plugs through the controlled section. The number of pulses corresponding to the number of liquid plugs is determined with the help of counter 6, the duration of the signal corresponding to the transit time of the liquid tube through the controlled section is determined with the help of counter 9, which is filled through the AND 7 circuit with standard pulses from the reference frequency generator 8 passing the liquid tube through a controlled section. Signal

at the outlet of the dividing device 10 corresponds to the average duration of the passage time of the fluid tube, which is judged on the speed and volumetric flow rate of the gas-liquid flow.

Thus, the proposed method makes it possible to control the volumetric flow rate of gas-liquid flows of the pipeline cross section, and the flow rate Q is determined by the projectile structure in a wide range of variation of the flow parameters of the mixture with a fairly simple implementation of the method using a single primary converter.

divide by addiction

K-10D-S

4t 15 where K is the non-uniformity coefficient

phase speeds; D is the diameter of the pipeline; S is the cross-sectional area

Claims (1)

Invention Formula The method of determining the flow rate of gas-liquid flows with a projectile structure, which consists in determining the rate of fluctuations of structural inhomogeneities in a controlled flow cross section, according to which flow is judged, characterized in that, in order to simplify the measurement process, determine the average rate of passage of the liquid plug through given section of the pipeline, and the flow rate Q is determined by divide by addiction K-10D-S 4t where K - coefficient of non-uniformity phase speeds; D is the diameter of the pipeline; S is the cross-sectional area  pipeline; The average duration of the fluid tube signal.