SU1062524A1 - Method of measuring consumption of gas having dariable parameters - Google Patents

Abstract

A METHOD FOR MEASURING A GAS FLOW WITH VARIABLE PARAMETERS g includes measurements of pressure drop across a constricting element, temperature and pressure in front of it and the introduction of a corrective action, characterized in that, in order to ensure an accuracy of measurement in the range of temperature and gas pressure, corrective action is to a controlled flow at the inlet of the flow meter, at V this product j ---- is kept constant, where Рд, Рр are the actual and calculated values of pressure, respectively; Td, Tp are the actual and calculated values of the temperature, respectively.

Description

The invention relates to a measurement technique and can be used in automated monitoring and control systems. In known gas flow monitoring and control systems, methods for determining the true gas flow rate as a function of the galling gradient and the actual values of the gas parameters are widely used to improve measurement accuracy. A known method for automatically determining the gas flow rate is based on measuring the actual value of the gas pressure and the subsequent correction of the flow rate by pressure using the means of computer technology 1. The disadvantage of this method is the unsatisfactory accuracy of measuring the true flow rate under conditions of varying gas temperature. A known method of automatically controlling the true flow rate of gas, according to which the actual parameters are taken into account by changing the area of the orifice of the restriction device in accordance with the current values of the gas parameters. The flow area is regulated by a profile plug, peremettsya bellows device, sealed {the cavity of which is filled with the measured gas. The cork profile is selected. So that the area of the orifice of the idmfragm is proportional to the value -, t where Rd, T. - respectively, the actual value, pressure and temperature of the gas flow. The differential pressure occurring in the diaphragm is proportional to the square of residual 2. The disadvantage of this method is a relatively narrow range of changes in the actual values of pressure and temperature. indications of the secondary device 3 A disadvantage of the known method is the low accuracy of the measurement of the gas flow in the range of temperature variation and pressure . The purpose of the invention is to improve the measurement accuracy in the range of changes in temperature and gas pressure. The goal is achieved by the fact that a corrective action is made on the controlled flow at the inlet A of the R domer, whereby the product A maintains its value, where Pd, Pd is the actual and calculated pressure value; T, Tp are the actual and calculated temperatures respectively. The drawing shows a diagram of the device that implements the proposed method. The device contains sensors 1-3 of pressure, temperature and flow, respectively, with the corresponding converters 4, 5 and b of the measured parameter into a unified signal, software converter .7 by parameter, controller 8, secondary device 9, valve 10 and heat exchanger 11, c the case when the driving parameter is the gas pressure, and its temperature is adjustable. A variant of this device is a device in which the setting parameter — the gas temperature (A) and adjustable — the gas pressure at the heat exchanger outlet. The method is carried out as follows. The actual gas temperature is monitored by sensor 2 and converted by the converter 5 into a pneumatic signal, which is fed to the input of software converter 7 according to the parameter at the output of which a pneumatic signal is generated that determines the setting of the regulator 8. Depending on the actual pressure value monitored by sensor 1, the converter is 4, the pneumatic signal of the corresponding value arrives at the input of the variable regulator B, In the case of the unbalance of the pneumatic signals of the variable task on you (during the regulator 8, a control is formed the TRANSFER signal to the valve 10, which determines the gas pressure. In this case, the software converter 7 according to the parameter generates a signal for the value of the gas pressure so that if the pneumatic signals coming to the regulator 8 are equal, to ensure the conditions of the constant values of pressure to the temperature of the calculated, the temperature of the temperature to the advance lg-. in this Case, the actual gas flow measured by sensor 3 and converter 6 and controlled by the secondary device 9 corresponds to the true value of uw E.llP.T. To de E, Ed. a correction factor for the expansion of the measured medium, calculated SNG and real, respectively;

K, is the compressibility factor of the gas, calculated and real, respectively. onpefleJjeHHii. gas consumption priit

what "yes

and it is understood.

value.

Using the proposed method expands the range of variation.

gas parameters (Р, Т) when measuring gas consumption in various technological processes,

The use of the proposed device, for example, in the production of 1 ml of a slitter allows you to get an economic effect of 20 thousand rubles. per year when measuring the flow rate of gaseous ammonia at the entrance to the neutralization apparatus.

Claims (1)

METHOD FOR MEASURING A GAS CONSUMPTION WITH VARIABLE PARAMETERS, including measuring the pressure drop across the constricting element, the temperature and pressure in front of it and introducing a corrective action, characterized in that, in order to ensure measurement accuracy in the range of gas temperature and pressure changes, the corrective effect is produced on the controlled flow at the inlet of the flow meter, with ^R A ^T 7 this product ——— A ^p p are constant, where P, P _p are the actual and calculated pressure values, respectively; TD, T _p - respectively, the actual and calculation - § supported temperature values.