SU696292A1

SU696292A1 - Rate-of-flow meter

Info

Publication number: SU696292A1
Application number: SU782619246A
Authority: SU
Inventors: Азиз Шахрийяр Киясбейли; Марк Ефремович Перельштейн; Давид Александрович Непорент
Original assignee: Специальное Конструкторское Бюро "Нефтехимприбор"
Priority date: 1978-05-24
Filing date: 1978-05-24
Publication date: 1979-11-05

Description

1one

Изобретение относитс к приборостроению , предназначено дл измерени расходов жидкостей или газов.The invention relates to instrumentation, intended to measure the flow of liquids or gases.

В р де известных расходомеров (например , вихревых, турбинных с индуктивным преобразованием и т. п.) выходной сигнал представлен в виде напр жени переменного тока, частота и амплитуда которого пропорциональны значени м расхода 1.In a number of known flow meters (e.g., vortex, turbine with inductive conversion, etc.), the output signal is presented in the form of an alternating current voltage, the frequency and amplitude of which is proportional to the flow rate 1.

Сигнал выпр мл ют линейным выпр мителем и нормируют по напр жению посто нного тока в единицах расхода.The signal is rectified with a linear rectifier and normalized to the DC voltage in units of flow.

Расходомеры с использованием линейного выпр мител дл получени выходного напр жени посто нного тока, пропорционального значению расхода, имеют низкие метрологические характеристики в диапазоне устойчивой работы.Flowmeters using a linear rectifier to obtain an output DC voltage proportional to the flow rate have low metrological characteristics in the range of stable operation.

Известны также расходомеры, содержащие первичный преобразователь, усилительформирователь , частотомер и выходной блок 2.Also known flow meters containing a primary transducer, amplifier, frequency counter and output unit 2.

Сигнал усиливаетс , подаетс на автоматический регул тор усилени , управл емый напр жением, пропорциональным частоте сигнала. Регул тор автоматически поддерживаст посто нство амплитуды сигнала независимо от значений расхода. Затем сигнал подают на след щий фильтр, полоса пропускани которого зависит от напр жени , пропорционального значению расхода, формируют по длительности и преобразуют частотомером в нор п1рованную величину посто нного тока. В этих расходомерах нижний участок диапазона измер емых расходов отсекаетс пороговым устройством. Измер емый диапазон расходов ограничен и зависит от уровн помех.The signal is amplified, fed to an automatic gain control that is controlled by a voltage proportional to the frequency of the signal. The controller automatically maintains a constant amplitude of the signal regardless of the flow rate values. Then the signal is fed to the next filter, the bandwidth of which depends on the voltage proportional to the flow rate, is formed over the duration and is converted by a frequency meter into a norm, a constant current value. In these flow meters, the lower portion of the range of measured flow rates is clipped by a threshold device. The measurable flow range is limited and depends on the level of interference.

Цель изобретени - расширение диапазона измер емых расходов с сохранением хорощих метрологических характеристик расходомера .The purpose of the invention is to expand the range of measurable flow rates while maintaining the good metrological characteristics of the flow meter.

Claims

This goal is achieved by simultaneously sending a signal to the inputs of a linear rectifier and frequency meter, the output voltages of these circuits are simultaneously fed to a comparison unit, which with the help of keys connects the frequency meter voltage to the output unit of the device, if it is greater than a predetermined reference voltage, or the application of a linear rectifier, if the voltage of the frequency meter is less than the reference voltage; 1I :(, lip / go:; x ;; ra d) -Sgik; u: - / ieHOHODOUT VYHS) DP (G (;; i L 11): / KL .: I; H I C i.) TOM C I15-. It is 11 cp) to; ,, and the mapping of characteristics is performed with overlap. The existence of the listed signs allowed () to divide the range of the measured flow rates, by 1 in the range: the initial section in which the measurement is performed using a linear rectifier, and the second half of the range where the measurement is performed by a frequency meter. The automatics subband switching allows to significantly spread out the range of my expenses with the preservation of a given value of the relative reduced crossover network over the entire range of measured flow rates. In the figure, a flowmeter flow diagram is presented. The flow meter contains a transducer 1 of the flow rate of the measured flow in the Electric signal, the amplifier-driver 2, the linear synchronizer 3, the frequency meter 4, the source of the reference voltage 5, the equation block 6, the keys 7, 8 the output block 9. The measured medium 1 goes through The flow transducer I, where an alternating current signal is formed, is proportional to the flow rate. The signal is amplified and formed by inserting. 1m 2 and rectifying with a linear rectifier 3 to a DC voltage proportional to the flow rate. At the same time, rectangular i.nulses, normalized by duration and amplitude by a shaper, whose frequency is proportional to the flow rate, are supplied to a frequency of mrp 4, which converts them into a current HOSTOYNN01-0 voltage, proportional to the flow rate. The characteristics of both transducers have the same inclination to the axis of abpess. The output voltage of the frequency meter | 4 is equalized in the comparison unit 6 with the reference voltage of the net voltage 5. With the values of voltage on the output of the frequency meter, which exceed the value of the reference voltage, the output of the frequency meter is connected via the key 7 to the common speed switch. b this is the case when the voltage of the frequency meter is less than the reference one, the output unit 9 is connected via key 8 to linear switch 1 1 square meter 3, frequency 4 to: 1 by switch 7 is turned off. The magnitude of the reference voltage is chosen such that the frequency meter 4 or linear rectifier / t 3 is connected to the output unit 9 in the most favorable for them operating conditions. In the upper part of the range of measured flow rates, where the signal's amplitude is sufficiently large, which ensures its reliable formation, which is necessary for accurate operation of the frequency meter, it is connected to meter 4. At a small flow rate section, where the signal amplitude is insufficient for unambiguous formation of impulses , b.yuk of comparison 6 connects to output unit 9 via key 8 linear winding device 3. Increasing the absolute error in this part of the flow range does not increase the relative reduced flow rate as a whole. Claims of the invention Rahedra meter comprising a primary converter, an amplifier-driver, a frequency meter and an output unit, characterized in that, in order to expand the measurement range, it is provided with a linear array connected to the output of the amplifier of the imager, and a block. Compared with two switching elements at the output, the input of which is connected to the output of the frequency meter, and the output - to the output unit, and the input of one of the switching elements is connected to the output of the linear rectifier, and the other to the output of the frequency meter. Sources of information taken into account in the examination 1. US patent number 3473377. CL. 73-194, 1969.

2. US patent number 3709034, class. 73-194, 1973 (prototype).