SU1633286A1 - Method for determining instant flow - Google Patents

Abstract

The proposed method can be used in the chemical, fuel industry, in particular, for measuring the instantaneous consumption in cryogenic engineering. The aim of the invention is to improve the accuracy of determining the instantaneous flow rate of a user’s fluid in installations in which the flow meter is located at a distance from the consumer, and the change in the density of the liquid is due to its temperature heterogeneity. The essence of the method is as follows. during the measurement of the flow rate, the density differs from that measured by the flow meter located at a certain distance from the consumer. temperature and pressure at the site of installation of the flowmeter and the consumer and determine the time of setting the fluid motion flowmeter to the consumer area. The instantaneous volume flow rate is determined by the formula QT Qm.LЈl Where QT is the instantaneous volume pp, the flow rate of the liquid for the consumer; Qpr is the instantaneous volume flow measured by the flow meter, pp is the fluid density in the flow meter installation area at the time of flow measurement QPT, pni is the fluid density calculated from the pressure of the consumer and the temperature Tp, (T ,,,), where Glt is the fluid temperature the consumer at the time of flow measurement; T ,,, is the temperature in the installation area of the flow meter at the point in time preceding the measurement of QPT flow rate at 6t, ГР1 is the liquid temperature at the flow meter. The essence of the method in the case of measuring the mass flow rate is as follows. The instantaneous mass flow rate calculated from the volume flow rate and density is not the same due to the difference in the density of the liquid at the installation site of the flow meter and that of the consumer. It is proposed to determine the instantaneous mass flow rate at the input to the consumer MT by the formula or Mr QPTpp (). where Ppp MP1 is the instantaneous mass flow rate of the fluid in the installation area of the flow meter at the time of measurement t, pp () is the density of the liquid calculated by temperature, in the installation area of the flowmeter at the time point, prior to the flow measurement at the consumer and the pressure in the pipeline. 2 h. p f-ly Ј (L o & O GO o 00 O5

Description

The invention relates to a measurement technique and is intended for use in the chemical, fuel industry, in particular for measuring consumption in a cryogenic technique.

The aim of the invention is to improve the accuracy of determining the instantaneous fluid flow rate at a consumer in installations in which the flow meter is located at some distance from the consumer, and the change

fluid density due to its temperature heterogeneity

When determining the instantaneous volumetric ITI of the mass flow rate of fluid in the pipeline at some distance from the consumer, there is an error caused by the pressure drop and the temperature difference of the fluid in the line between the flow meter stop zone and the entrance to the consumer

To determine the instantaneous volumetric flow rate of the fluid at the inlet to the consumer, the instantaneous volumetric flow rate of the fluid in the installation zone of the flow meter Qp is measured, as well as in the flow meter installation unit, the temperature is measured and the pressure is Gy and the pressure Pgt at the time of measuring the flow rate determine the totality of the liquid pt. Additionally, appropriate transformations with seams are measured and 5 measures the temperature Tf and the pressure Pf of the fluid at the inlet to the consumer and the same time instant t

With the help of a chronometer started, for example, by a source of a flow label, installed in the area of the flow meter and stopped by the indicator of the label located at the entrance to the consumer, the time is measured

1) the movement of liquid bt from the flow meter to the consumer. Using a memory device, the temperature is measured) at the instant of time preceding the time of the consumption of the flow rate on the interval bt.

1ention P „t and temperature G„ | T, found by formula

 Fri Fri (p i - 6t) I PTJI

and the value of the instantaneous volumetric flow rate of the fluid at the inlet to the consumer Q, is determined by

p-p

VTVPT

() PT

The thickness of the method in the case of measuring the mass flow rate is included in the following

When placing the volume flow converter, which measures the instantaneous flow rate of the fluid, as well as the pressure transducers Prt, the temperatures TP1, which determine the fluid to full ppm, at some distance from the consumer at the location of the flow meter for more accurate measurement of the mass flow rate of the fluid at the inlet to the consumer at the moment of time t is measured by the chronometer started by the source and stopped by the indicator, or the time interval τ of the movement of fluid from the flow meter to the consumer is determined, and also, using memory devices, the temperature is measured at the moment of time preceding the moment of measurement of the flow rate for the interval of time BT, over which

Rtr determine the density of the liquid) The value of the instantaneous mass flow rate at the entrance to the consumer / VfT is determined by the formula

,

RR (t-w)

t Rt

or

0

five

0

Mt rt-pp (t-6t),

where Mrt and (2tr are, respectively, instantaneous mass and volumetric flow rates of fluid in the flow meter installation area

Claims (3)

Invention Formula 1 Method for determining the instantaneous flow rate of a fluid, which consists in determining the flow rate and density of the fluid according to its temperature and pressure in the installation area of the flow meter in the pipeline, characterized in that, in order to improve the accuracy of determining the instantaneous flow rate of the consumer in installations in which the flow meter is located at some distance from the consumer, and the change in the density of the medium due to its temperature heterogeneity, additionally measure the time interval for the movement of fluid from the flow meter to the consumption and temperature of the fluid in the meter setting zone at a time preceding the time of measuring the flow of fluid at a time interval of movement of the meter to the consumer, and determining an instantaneous flow rate value from the measured values of the consumer 2. Method according to claim 1, characterized in that, in determining the instantaneous volume flow, the pressure and temperature of the fluid at the inlet to the consumer are additionally measured, the density of the fluid at the consumer is determined by the pressure of the consumer and the temperature  n 1: fr {p (t -6t) rt) where is the temperature of the fluid in the pot, 7 rgt-gsh - the temperature of the liquid in the zone of installation of the flow meter at the point in time preceding the measurement for the time interval of the movement of the liquid from the flow meter to the consumer, Gy - the temperature of the liquid in the installation area of the flow meter, and the value of instantaneous flow rate QT is determined by the formula f) D) RRT VTC / RT, Ppt 5 where frt is the instantaneous volumetric flow rate of the fluid in the installation zone of the flow meter, RPT is the density of the fluid at the consumer. five 0 five 0 1633286 56 3. The method according to claim 1, characterized in that Prg irr (T bt | - the density of the fluid in place the determination of the instantaneous mass flow rate of the flow meter, consumer M, is made according to the formulas determined at the time of measurement at the time, М1 Мрт-Рр (t-6t or MT Qpt-pp (5) PPTmeasurement of the ing-meter Mr-, and Qp, - respectively, instantaneous time interval of movement mass and volume flow of the flow meter dy of fluid in the installation-to-consumer zone;