JPS63293417A - Gas flow measuring method and device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for measuring the flow rate of gas passing through an opening in a conduit and an apparatus therefor.

(Prior Art and Problems) Gas flow rate measurement is performed in various ways. For example, mechanical flow meters are used.

In this flow meter method, a measured flow rate of gas is passed through a set of movable bellows through a set of slide valves. Together with the valves, these bellows also drive mechanical counters.

However, the drawbacks of the conventional measuring methods and devices described above are that the measurement errors vary from time to time as a result of variations in the operating conditions of the bellows, and that mechanical parts may wear out. As a result, the error variation far exceeds the allowable value. Also, another drawback is that the pressure and temperature variations of the gas are completely ignored, and the supplied gravimetric flow values do not match the respective supplied volumetric flow values when measuring the energy values. .

(Means, Actions, and Effects for Solving the Problems) An object of the present invention is to provide a measuring method and device that do not have the drawbacks of the conventional methods and devices described above.

In order to achieve the above object, the present invention relates to a gas flow rate measuring method, and in a method for measuring the flow rate of gas passing through an opening, a series of binary crack valves having mutually different maximum passage capacities are arranged in parallel. and a pressure sensor controlling the regulating system with a signal corresponding to the deviation between the overall pressure drop of the gas as it passes through the valve device and a set value. The pressure drop is maintained at a set value by constantly and continuously detecting the deviation, the crack in the valve device is opened and closed by the signal, and the volumetric flow rate is read by the position of the valve device.

A binary system is installed in the gas passage.
A series of on-off crack valves arranged in parallel as tem) is known per se. However, the application of a binary crack valve such as the present invention for flow measurement is not known.

In a preferred embodiment of the present invention, the fine adjustment of the pressure drop at small gas flow rates is achieved by cracking a binary crack valve with a minimum maximum throughput capacity, which is continuously adjustable between open and closed positions. It is best to do this by adjusting. Also, by measuring these small gas flow rates, the overall range of measurement is expanded without affecting measurement accuracy.

In order to make it possible to measure the weight flow rate of gas, corrections must be made based on the pressure and temperature of the gas inside the pipe. A preferred form for this is that the temperature and pressure of the gas in the line are determined by means of a sensor to correct the volumetric flow rate in order to determine the gravimetric flow rate of the gas passing through the opening. It is better. Sensors can measure gas temperature, differential pressure across the valve, and overpressure directly on the binary crack valve. Pressure measurements are extended by making absolute pressure measurements, increasing accuracy in determining gas gravimetric flow rates.

In particular, it is advantageous to carry out the modification using a microprocessor. The microprocessor may also include a measurement error determined during the calibration of the metering device, which may be stored in a built-in memory during said calibration in determining the weight flow rate.
ry). As a result, each meteor of gas measured under the monitoring of the individual deviation characteristics of each device is measured and calculated with high precision as a weight flow rate.

If it is desired to measure the amount of heat for a specific flow rate of gas, the microprocessor may be configured based on the composition of the gas. When measuring pressure and temperature, the properties of the gas may change slightly. Therefore, it is better not only to store the characteristics as fixed data in memory, but also to make them dependent on changes in pressure and temperature. By including the actual characteristics of the gas at the time of measurement, the measurement accuracy will be improved when determining the amount of heat.

The present invention relates to a device for carrying out the above measurement method, and a device for measuring the flow rate of gas passing through an opening, which includes a valve device comprising a series of binary crack valves having mutually different maximum passage capacities arranged in parallel. arranged at the back of said opening to measure the difference occurring in the pressure drop of the gas as it passes through said valve arrangement, adjusting the position of the crack in said binary crack valve by being controlled by the difference in said pressure drop; The pressure sensor is connected to the system.

Here, it is preferable that the crack of the binary crack valve having the minimum maximum passing capacity can be adjusted continuously by 8 Pi between the open and closed positions.

If it is desired to measure the weight flow rate of gas, the conduit may be provided with a temperature sensor and a pressure sensor, both of which may be connected to the gas flow rate measuring section.

Here, it is more preferable that the gas flow rate measuring section is a microprocessor.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings. FIG. 1 is a schematic diagram showing each part of the apparatus of this embodiment, and FIG. 2 is a diagram showing the relationship between the measured value of the gas flow rate and the permissible error percentage.

In FIG. 1, gas flows into the valve device 2 in the direction indicated by the arrow.
It flows through conduit 1 through . In the valve device 2, a plurality of binary crack valves (binary crack valves) are arranged.
es) are arranged in parallel. Measuring pipes are connected to both sides of the valve device 2, and pressure sensors 3 are provided therein, so that the pressure difference on both sides of the valve device 2 is measured via the measuring pipes.

The measured value is then transmitted to the microprocessor.

A microprocessor with memory and a drive unit for controlling the cracking of the binary crack valve are housed in the section 4 of the flow metering section which houses all the electronic circuits and the control unit 5. The temperature of the gas is determined by a temperature sensor 6 connected to the microprocessor.
It is measured by. The electronic circuit is connected to a power source as indicated by 7.

In FIG. 2, the vertical axis shows the deviation percentage, and the horizontal axis shows the weight flow rate of gas flowing per unit time.

Curve 8 shows the accuracy of the gas gravimetric flow rate as determined by the present invention. The other two curves 9 and 10 show the deviation range when the weight flow rate of gas per unit time is determined based on the pressure and temperature of the gas supplied into the pipe in a mechanical measuring device. .

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing each part of the embodiment device of the present invention, and FIG.
The figure is a diagram showing the relationship between the measured value of gas flow rate and the permissible error percentage. ■・・・・・・・・・Opening (pipe line) 2・・・・・・・・・Valve device 3・・・・・・・・・Pressure sensor 4・・・・・・Adjustment System 6...Temperature sensor patent applicant EM Niss Holland P.V.

Claims (9)

[Claims] (1) In a method of measuring the flow rate of gas passing through the opening 1, the gas is passed through a valve device 2 formed by a series of binary crack valves having mutually different maximum passing capacities arranged in parallel; 2 by constantly and continuously detecting said deviation with a pressure sensor 3 which controls a regulating system 4 with a signal corresponding to the deviation between the overall pressure drop of the gas as it passes through the gas and the set point. A method for measuring a gas flow rate, comprising: maintaining a gas flow rate at a set value, opening and closing a crack in a valve device according to the signal, and reading the volumetric flow rate based on the position of the valve device. (2) Fine adjustment of the pressure drop at small gas flow rates is achieved by adjusting the above capacity by cracking a binary crack valve with a minimum maximum throughput capacity, which is continuously adjustable between open and closed positions. A gas flow rate measuring method according to claim (1). (3) A patent characterized in that, in order to determine the gravimetric flow rate of the gas passing through the opening 1, the temperature and pressure of the gas in the conduit are determined by correcting the volumetric flow rate using a sensor. A gas flow rate measuring method according to claim (1) or (2). (4) The gas flow rate measuring method according to claim (3), wherein the correction is performed by a microprocessor. (5) To determine the amount of heat of the gas passing through opening 1,
4. The gas flow rate measuring method according to claim 4, wherein the microprocessor is adjusted depending on the gas component. (6) In a device for measuring the flow rate of gas passing through an opening 1, a valve device 2 comprising a series of binary crack valves arranged in parallel with mutually different maximum passing capacities is provided at the back of the opening 1, In order to measure the difference occurring in the pressure drop of the gas as it passes through the valve arrangement 2, a pressure sensor 3 is provided in the system 4 which adjusts the position of the crack in the binary crack valve by being controlled by the difference in said pressure drop. A gas flow measuring device characterized in that: (7) The gas flow rate measuring device according to claim (6), characterized in that the crack of the binary crack valve with the minimum maximum passing capacity can be adjusted continuously between both open and closed positions. . (8) The gas flow rate according to claim (6) or (7), wherein the pipe line is provided with a temperature sensor and a pressure sensor, both of which are connected to a gas flow rate measuring section. Measuring device. (9) The gas flow rate measuring device according to claim (8), wherein the gas flow rate measuring section is a microprocessor.