RU2783916C1 - Method and device for measuring flow and quantity of liquids and gases using reducing devices - Google Patents

Abstract

FIELD: flow rate accounting measurement.

SUBSTANCE: invention is intended to provide measurement and accounting of the flow rate and quantity of liquid and gaseous media, supply and consumption of thermal energy and coolant, gas, steam, water and other similar media and expand the range of measured flow rates in a wide range of measured media densities. In the method for measuring the flow rate and the amount of liquids and gases, the calibration function of the dependence of the identification parametric coefficient on the volumetric flow rate for the reference volumetric flow meter and the pressure drop across the restrictive device is preliminarily determined for the constriction device by calibrating (verifying) the constriction device with a volumetric exemplary flow meter for each point of the normalized range volume flow and pressure drop across the narrowing device from the minimum to the maximum range of the measured flow rate at a known, constant and controlled density of the working medium, and the measurements of the flow rate and the amount of liquids and gases are carried out with the simultaneous determination of the density of each normalized volume unit of the measured working medium, and the mass flow rate of each normalized volume unit of the measured working medium is determined taking into account the readings of a volume flow meter installed in series with a narrowing device on one measuring line, measuring volume and volume flow, which are read by the controller, which determines the identification coefficient of the narrowing device at each point of volume flow using a pre-calibrated restrictive device using the calibration function, and determines the density and mass flow rate of each normalized unit of volume from the pressure drop and volume flow. In addition, the volume flow meter is assembled in the body of the constriction device.

EFFECT: reduction of the relative error in measuring the flow rate and the amount of the medium due to a more accurate determination of the identification parametric coefficient of the narrowing device, determining the density of each normalized unit of volume, expanding the range of measured flow rates in terms of density.

3 cl, 5 dwg

Description

The method and device for measuring the flow and quantity of liquids and gases using constricting devices relates to the field of measuring and accounting for the flow and quantity of liquid and gaseous media passed through the pipeline during commercial and / or technological accounting of thermal energy, liquid and gaseous fuels, natural gas, water steam, water and other similar media, in metering units built on the basis of narrowing devices and pressure drop converters.

The invention is intended to provide measurement and accounting of the flow rate and quantity of liquid and gaseous media, supply and consumption of thermal energy and coolant, gas, steam, water and other similar media and expand the range of measured flow rates in a wide range of measured media densities.

Known "Narrowing device for measuring gas flow" (RF patent 2366899 C1 10.09.2009 Bull. No. 25).

This constriction device for measuring gas flow includes a cylindrical body with a slot in which the measuring diaphragm is located, a stepped flange with a cylindrical groove included in a cylindrical bore made on one side of the body to form a detachable connection with the body, the gap in the body is closed from the outside by an overlay, and from below - a cover with a seal placed inside the body with the ability to move around the circumference, limited by a stop rigidly installed inside the body, the flange end is equipped with a lodgment made in the form of two axisymmetrically placed semi-rings centering the measuring diaphragm pressed against the flange by studs, while the cover with a seal and an overlay are centered with the help of a spacer installed in the slot and having the shape of a half ring and tightened with studs and nuts.

The calculation of this narrowing device is carried out in accordance with the requirements of GOST 8.586.1 ... 5-2005 "Measurement of the flow rate and quantity of liquids and gases by the method of variable pressure drop", in particular, for the specific density of the intended medium being measured.

In a real situation, the density of the measured medium can change for various reasons, and this change in density is not reflected in any way and is not taken into account in the measurement results, which introduces a significant inaccuracy, an error in the measurement results, which is a significant drawback of this measurement method and limits its use in a wide range measured environments.

The device "Venturi flow meter with vacuum insulation for the exhaust gas recirculation system" is known (RF patent 2605489 C2 20.12.2016 Bull. No. 35).

Venturi flow meter for placement in a cooled exhaust gas recirculation (EGR) system that includes an exhaust gas recirculation pipeline. The exhaust gas recirculation pipe is connected to the exhaust pipe of the internal combustion engine. The exhaust gas recirculation system includes an EGR system cooler, which is connected to the exhaust gas recirculation pipeline. A Venturi flow meter is connected in the exhaust gas recirculation pipeline to receive exhaust gases from the EGR system cooler. In this case, the Venturi flow meter has an inner wall that forms the inner space. The interior space includes a tapering inlet, a tapered portion and a widening outlet. The outer wall surrounds and is attached to the inner wall. Moreover, the outer wall is spaced apart from the inner wall with the formation of an insulating space between the inner and outer walls. Also disclosed is an exhaust gas system for an internal combustion engine containing a Venturi flow meter.

The disadvantage of this analog is that the measurements of the amount of exhaust gases are made at a given calculated density, which can change during the measurement process for various reasons, and the measurement results are not expected to be corrected due to changes in density.

An analogue of this invention, selected as a prototype, is GOST 8.586.1...5-2005. "Measuring the flow and quantity of liquids and gases by the method of variable pressure drop".

In the aspect of the present invention, along with a method for measuring the flow and quantity of liquids and gases using constriction devices, a device for measuring the flow and quantity of liquids and gases is also proposed.

According to this method of measurement, the design contains a narrowing device located on the measuring pipeline. The pressure drop across the restrictor is measured with a pressure drop transducer. The temperature of the medium in the pipeline is measured by a temperature sensor. The pressure of the medium in the pipeline is measured by a pressure sensor. According to the measured pressure drop across the orifice, the temperature and pressure of the medium in the pipeline, the predetermined parameters of the orifice, the measuring pipeline and the thermophysical parameters of the medium (density, viscosity, enthalpy, etc.), the calculator calculates the flow rate and amount of the medium using known methods given in GOST 8.586.5-2005 “Measuring the flow and quantity of liquids and gases by the method of variable pressure drop. Measurement technique”.

According to this method, the mass flow rate of the medium is calculated by the formula:

qm =K( _2ρΔρ ) ^0.5 _,

where

K=(πd ² /4) C E ε,

where parameters:

K - identification parametric coefficient of the narrowing device;

d - diameter of the opening of the narrowing device;

C - coefficient of flow of the narrowing device;

E - speed coefficient of the entry of the narrowing device;

C * E - consumption coefficient;

Δρ - pressure drop across the narrowing device;

ε - expansion coefficient;

π - mathematical constant;

ρ is the density of the measured medium;

q _m - mass flow rate of the medium;

q _ν - volumetric flow rate of the medium under operating conditions.

In this case, these parameters are measured directly, or calculated from the results of measurements of other parameters, and the pipe expiration coefficient depends on a number that depends on the flow rate of the medium, the Reynolds number, and therefore the equation for calculating the flow rate may be implicit, which is a significant disadvantage of this analog.

Along with this, another significant disadvantage of the analog is the use of a narrowing device for a specific density of the measured medium. This also limits the range of application of the narrowing device.

The objective of the invention is to improve the accuracy of measuring the flow rate and quantity of liquids and gases using constriction devices.

The technical result of the claimed invention is expressed in a decrease in the relative error in measuring the flow rate and the amount of the medium due to a more accurate determination of the identification parametric coefficient of the narrowing device, determining the density of each normalized unit of volume, expanding the range of measured flow rates by density.

The problem is solved and the technical result of the method for measuring the flow rate and quantity of liquids and gases using constriction devices is achieved by the fact that, according to the invention, for measuring the flow rate and quantity of liquids and gases, the calibration function of the dependence of the identification parametric coefficient on the volumetric flow rate is preliminarily determined for the constriction device according to the reference volume flow meter and pressure drop across the restrictor according to the formula

K=q _ν [ρ/(2Δρ)] ^0.5

by calibrating (verifying) the narrowing device with a volumetric exemplary flow meter for each point of the normalized range of volume flow and pressure drop on the narrowing device from the minimum to the maximum range of the measured flow rate at a known, constant and controlled density of the working medium, and the flow and quantity of liquids and gases are measured with simultaneous determination of the density of each normalized volume unit of the measured working medium according to the formula

with an identification parametric coefficient K corresponding to the flow rate q _ν according to the calibration function from the indication of a working volumetric flow meter located on the same measuring line with the constriction device, taking into account the pressure drop Δρ on the constriction device, and the mass flow rate of each normalized volume unit of the measured working medium is determined by the formula

q _m =q _ν ρ

The problem is solved and the technical result of the device for measuring the flow and quantity of liquids and gases using constriction devices, consisting of a constriction device on the measuring line, a differential pressure converter connected by impulse tubes to the pressure sampling holes of the constriction device, a pressure sensor, a temperature sensor, a controller, which reads signals from differential pressure transducers, a pressure sensor, a temperature sensor, and calculates the flow rate and quantity of the medium, according to the invention, a flow meter is installed in series with the narrowing device on the same measuring line, which measures the volume and volume flow, which are read by the controller, which determines at each point the volume flow according to to a pre-calibrated orifice, from the calibration function, the identification coefficient of the orifice, and from the pressure drop and volume flow determines the density and mass flow of each normalized volume unit a.

In addition, according to the invention, the volume flow meter is assembled in the body of the constriction device.

The essence of the invention is illustrated in Fig. 1, 2, 3, 4, 5.

In FIG. 1 is a diagram of a device with a volume flow meter installed in series, measuring volume and volume flow.

In FIG. 2 is a diagram of a device with a flow meter installed in the body of the narrowing device, which measures volume and volume flow.

In FIG. 3 is a diagram of a device with an ERVIP.NT.M.Zh.-050/025 vortex flowmeter installed in the body of the constriction device, which measures volume and volumetric flow.

In FIG. 4 is a graph of the dependence of the identification parametric coefficient of the device with the vortex flowmeter ERVIP.NT.M.Zh.-050/025 installed in the body of the constriction device.

In FIG. 5 table of calibration (verification) of the device with the vortex flowmeter ERVIP.NT.M.Zh.-050/025 installed in the body of the narrowing device.

The device for measuring the flow and quantity of liquids and gases using constriction devices contains a constriction device 1 on the measuring line 2, a differential pressure converter 3 connected by impulse tubes 4 with pressure sampling holes 5 of the constriction device 1, a pressure sensor 6, a temperature sensor 7, a controller 8 and in series with the constriction device 1 on the same measuring line 2, a working flow meter 9 is installed, which measures the volume of the measured medium and the volume flow q _ν , which are read by the controller 8, which determines at each point of the volume flow q _ν according to the pre-calibrated constriction device 1 on the calibration function the identification coefficient K narrowing device 1, and the pressure drop Δρ and volume flow q _ν calculates the density ρ and mass flow q _m of each normalized volume unit of the measured medium.

The device is brought into working condition as follows.

On the calibration bench, the calibration function of the dependence of the identification parametric coefficient K on the volume flow q _ν is preliminarily determined for the constriction device 1 according to the exemplary volumetric flow meter (not shown in Fig.) and the pressure drop Δρ on the constriction device 1 according to the formula

by calibrating (verifying) the constriction device 1 with a volumetric exemplary flow meter for each point of the normalized range of volume flow q _ν and the pressure drop Δρ on the constriction device 1 from the minimum to the maximum range of the measured flow rate at a known, constant and controlled density ρ of the working medium, the identification parametric coefficient K is determined The calibration function of the dependence of the identification parametric coefficient K on the volume flow q _ν according to the reference volumetric flow meter and the pressure drop at a known, constant and controlled density ρ on the constriction device 1, obtained as a result of calibration (verification) of the constriction device 1, is recorded in the memory of the controller 8.

The operation of the device is as follows.

The controller 8 from the working volume flow meter 9 reads the flow of normalizing units of volume, determines the current volume flow q _ν and, using the calibration function of the dependence of the identification parametric coefficient K, finds the current identification parametric coefficient K and, simultaneously reading the current pressure drop Δρ, calculates the density according to the formula

and the mass flow rate of each normalized volume unit of the measured working medium is determined by the formula

q _m =q _ν ρ

According to the measured temperature and pressure of the medium by sensors 5 and 6, the temperature and pressure in the measuring line 2, and the thermophysical parameters of the measured medium by the controller 8, the flow rate and amount of the medium are brought to standard conditions by known methods.

An example of a specific implementation of the method.

To implement the method and device for measuring the flow and quantity of liquids and gases using constriction devices, a certified vortex flowmeter for measuring liquid volume ERVIP.NT.M.Zh.-050/025 with a body length of 200 mm, with an inlet diameter of 50 mm passing to narrowing device with a hole of 25 mm (Fig. 3).

On the flow meter ERVIP.NT.M.Zh.-050/025, at the transition from a diameter of 50 mm to a diameter of 25 mm, a differential pressure transducer of the Piezoelectric company, the city of Rostov-on-Don, type 414-DD-VN model 5434, is installed.

On the verification stand for the vortex flowmeter ERVIP.NT.M.Zh.-050/025, as for the narrowing device 1, the calibration function of the dependence of the identification parametric coefficient K on the volume flow q _ν was determined using the exemplary volumetric flowmeter and the pressure drop Δρ on the narrowing device 1 according to the formula

by calibrating (verifying) the narrowing device 1 with a volumetric reference flow meter according to the characteristic eight points of the normalized range of volume flow q _ν and the pressure drop Δρ on the narrowing device 1 from the minimum to the maximum of the measured flow rate range for this flow meter at a known, constant and controlled density ρ of the working medium, in this case for water, the calibration function of the identification parametric coefficient K was determined in the form of table 1 and graph 1. The calibration function of the dependence of the identification parametric coefficient K on the volume flow q _ν according to the reference volume flow meter and the pressure drop at a known, constant and controlled density ρ at the narrowing device 1, obtained as a result of calibration (verification) of the narrowing device 1, is recorded in the memory of the controller 8.

The operation of the device is as follows.

The controller 8 from the working volume flow meter 9 reads the flow of normalizing units of volume, determines the current volume flow q _ν and, using the calibration function of the dependence of the identification parametric coefficient K, finds the current identification parametric coefficient K and, simultaneously reading the current pressure drop Δρ, calculates the density according to the formula

and the mass flow rate of each normalized volume unit of the ERVIP.NT.M.Zh.-050/025 vortex flowmeter of the measured working medium is determined by the formula

q _m =q _ν ρ

The dependence of the identification parametric coefficient K is shown in Fig. four

After determining the calibration function of the identification parametric coefficient K, the instrument is calibrated using standard means in terms of density, volume and mass.

The verification results are given in Table 1.

The proposed method and device for measuring the flow and quantity of liquids and gases using constriction devices improves the accuracy of measuring the flow and quantity of liquid and gaseous media, the release and consumption of thermal energy and coolant, gas, steam, water and other similar media, expanding the range of measured flow rates.

The use of the invention will make it possible to create a device that is simple and reliable in operation, measuring the flow rate in a wider range of densities of the measured media.

Claims (7)

1. A method for measuring the flow rate and quantity of liquids and gases using constriction devices, which consists in preliminarily determining for the constriction device the calibration function of the dependence of the identification parametric coefficient K on the volume flow according to the exemplary volumetric flow meter and the pressure drop across the constriction device according to the formula

by calibrating the orifice with a volumetric exemplary flow meter for each point of the normalized range of volumetric flow and pressure drop across the orifice from the minimum to the maximum of the measured flow range at a known, constant and controlled density ρ of the working medium, and the flow and quantity of liquids and gases are measured simultaneously determination of the density of each normalized volume unit of the measured working medium according to the formula

with an identification parametric coefficient K corresponding by the calibration function to the flow rate q _v from the indication of a working volumetric flow meter located on the same measuring line with the constriction device, taking into account the pressure drop Δр on the constriction device, and the mass flow rate q _m of each normalized volume unit of the measured working medium is determined by the formula q _m = q _v ρ. 2. A device for measuring the flow and quantity of liquids and gases using constriction devices, consisting of a differential pressure transducer connected by impulse tubes to the pressure sampling holes of the constriction device, a pressure sensor, a temperature sensor, a controller that reads signals from differential pressure transducers, a pressure sensor, a sensor temperature and calculation of the flow rate and quantity of the medium, characterized in that a flow meter is installed in series with the constriction device on the same measuring line, which measures the volume and volume flow, which are read by the controller, which determines at each point of the volume flow according to the pre-calibrated constriction device, according to the calibration function, the identification coefficient of the constriction device and by pressure drop and volume flow determines the density and mass flow of each normalized unit of volume. 3. The device according to claim. 2, characterized in that the volume flow meter is assembled in the body of the narrowing device.

Images