CN-121994312-A - Flow testing device and method for mixed gas

Abstract

The invention provides a mixed gas flow testing device and a testing method, which can accurately and conveniently measure the total flow of mixed gas and the flow of each component in the mixed gas by adopting the mixed gas flow testing device and the testing method by adopting a flowmeter to be matched with a concentration detector, and the flowmeter does not need to be calibrated again when the concentration of gas changes each time, so that the universality and the use efficiency of equipment are greatly improved.

Inventors

• LIU XIAOHU

Assignees

• 北京科纳理学科技有限公司

Dates

Publication Date

20260508

Application Date

20260227

Claims (2)

1. 1. The flow testing device for the mixed gas comprises a flowmeter (1) and a concentration detector (2), wherein an air inlet of the mixed gas is connected with an air inlet of the flowmeter (1), and the air inlet of the concentration detector (2) is connected with an air outlet of the flowmeter (1) and is used for measuring the concentration of each component of the mixed gas.
2. 2. The flow rate test method of the mixed gas comprises the steps of enabling the mixed gas to sequentially pass through a flowmeter (1) and a concentration detector (2), measuring a test value of the flow rate of the mixed gas by using the flowmeter (1), detecting the concentration of each component of the mixed gas by using the concentration detector (2), calculating a conversion factor of the mixed gas by using the concentration of each gas, and calculating a true value of the total flow rate of the mixed gas and a split flow rate of each component gas by using the conversion factor of the mixed gas, wherein the algorithm is as follows: In the above formula: f Mixed gas is the conversion factor of the mixed gas; f i is the conversion factor of each component in the mixed gas; c i is the concentration of each component in the mixed gas; The actual value of the total flow of the mixed gas and the flow of each component can be calculated by the conversion factor of the mixed gas, and the formula is as follows: In the above formula: F Mixed gas is the true value of the flow rate of the mixed gas; f Test value is a test value of the flow rate of the mixed gas measured by the flow meter; f i is the true flow value of each component in the mixed gas.

Description

Flow testing device and method for mixed gas Technical Field The invention relates to the technical field of fluid flow measurement, in particular to a flow testing device and method for mixed gas. Background The current flow meters mainly comprise vortex shedding flow meters, turbine flow meters, differential pressure flow meters, thermal flow meters, ultrasonic flow meters and the like. Taking a constant temperature differential thermal flowmeter as an example, the first internal sensor measures the temperature T0 of the gas, the second internal sensor is heated by the system, and a higher constant temperature value T1 is maintained, so that the two temperature sensors form a stable temperature difference delta T, and when the gas starts to flow, the heated second sensor is blown away to take away heat, and a cooling effect is generated. The greater the flow, the more heat is carried away, and in order to maintain the heated sensor at a set temperature in order to counteract the cooling effect, the control system must increase the heating current through the sensor, and the gas flow can be measured by measuring the current signal. While the principles of various types of flowmeters differ, the flow rate value is calculated essentially by sensing a change in a particular physical characteristic caused by the flow of gas and converting this change into a processable signal. In practice, the flow meter is typically calibrated with a specific gas, such as nitrogen, and then measured for an unknown flow of gas. Because of the difference in physical properties of different gases, when the measured gas is different from the calibration gas, the flow rate of the obtained test gas is often not the true value of the gas, for example, the flow rate value F t obtained by measuring helium by the flow meter is not the true helium flow rate F r, and the value is multiplied by the helium conversion factor F He to obtain the true helium flow rate, and the conversion factor is a known measured value, and the conversion formula is as follows: Typically, when measuring different kinds of pure gas, the flow meter can accurately measure the flow rate of the pure gas because its conversion factor is known. However, for a mixed gas with an unknown concentration, since the physical properties of the mixed gas strongly depend on the concentration ratios of the components thereof and the conversion factor is a physical function of the mixed gas, the conversion factor cannot be calculated because the concentration of the mixed gas is unknown, and therefore, the flow meter cannot accurately measure the flow rate of the mixed gas with an unknown concentration. Disclosure of Invention In order to solve the technical problems, the invention provides a device for testing the flow of mixed gas, which comprises a flowmeter and a concentration detector; The gas inlet of the mixed gas is connected with the gas inlet of the flowmeter, and the gas inlet of the concentration detector is connected with the gas outlet of the flowmeter and is used for measuring the concentration of each component of the mixed gas. The invention also provides a flow test method of the mixed gas, which comprises the following steps: Sequentially passing the mixed gas through a flowmeter and a concentration detector; obtaining a test value of the flow of the mixed gas through a flowmeter; obtaining concentration values of components of the mixed gas through a concentration detector; calculating the conversion factor of the mixed gas according to the concentration of each component of the mixed gas; The actual value of the total flow of the mixed gas and the flow of each component are calculated through the conversion factor of the mixed gas, and the algorithm is as follows: the conversion factor of the mixed gas is calculated through the concentration of each component in the mixed gas, and the formula is as follows: f Mixed gas is the conversion factor of the mixed gas; f i is the conversion factor of each component in the mixed gas; c i is the concentration of each component in the mixed gas; The actual value of the total flow of the mixed gas and the flow of each component can be calculated by the conversion factor of the mixed gas, and the formula is as follows: In the above formula: F Mixed gas is the true value of the flow rate of the mixed gas; f Test value is a test value of the flow rate of the mixed gas measured by the flow meter; f i is the true flow value of each component in the mixed gas. The mixed gas flow testing device and the mixed gas flow testing method have the beneficial effects that the mixed gas flow testing device and the mixed gas flow testing method which are matched with the concentration detector by adopting the flowmeter can accurately and conveniently measure the total flow of the mixed gas and the flow of each component in the mixed gas, the flowmeter is not required to be calibrated again when the concentration of the gas change