Gas flow measuring device and method based on ultrasonic bypass flow principle

Abstract

The invention relates to the field of gas flow detection, in particular to a gas flow measuring device and method based on an ultrasonic bypass flow principle and belongs to the field of novel metering instrument measurement. The device comprises a main pipeline and a bypass flow pipeline. The main pipeline is communicated with the bypass flow pipeline, the bypass flow pipeline is located on the side face of the main pipeline, a current blocking part is arranged in the main pipeline, a current limiting channel is formed, and an ultrasonic sensor is arranged in the bypass flow pipeline. A detection gas way is formed by the main pipeline, the bypass flow pipeline and the current blocking part jointly. By means of the method of flow division on the main pipeline, the current blocking part is arranged in the main pipeline, the monotone increasing relationship between the time difference value and the standard flow in the bypass flow pipeline is determined, the gas flow is tested, water and corrosion problems can be effectively solved, and accurate measurement of large-pipe-diameter gas flow can be achieved.

Description

technical field [0001] The invention relates to the field of gas flow detection, in particular to a gas flow detection device and method based on the principle of ultrasonic side flow, and belongs to the field of new metering instrument measurement. Background technique [0002] At present, in the measurement of gas flow, the corrosion of gas, the interference of moisture condensation, the inhomogeneity of gas flow field with large diameter, and the adaptability of gas over-range are different challenges faced by different gas flow measurement principles. Differential pressure gas flowmeter: The measurement accuracy is generally low, the measurement range is narrow, the requirements for the straight pipe section on site are high, the pressure loss is too large, and the over-range may even damage the measuring element, and the corrosive gas also has the risk of corroding the differential pressure element; Vortex street gas flowmeter: the range is relatively small, greatly aff...

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Problems solved by technology

In addition, while measuring the gas flow, the ultrasonic flowmeter can also measure the composition at the same time for some occasions. For example, the document CN103454344A first proposed the application of the ultrasonic principle in China, which can solve the simultaneous measurement of gas composition and flow. However, the current ultrasonic Several challenges faced by gas flowmeters are: (1) In gases with high ultrasonic absorption, such as biogas with high concentration of CO2 and natural gas with high concentration of CO2, the ultrasonic signal is very small due to the energy absorption signal, which is easy to cause errors or even errors , the larger the pipe diameter, the more serious the problem

(2) When used in large pipe diameters, the uniformity of cross-sectional flow field distribution cannot be guaranteed, resulting in measurement errors. (3) When there is moisture condensation in the measurement pipeline, such as in the field of biogas, when measuring the biogas coming out of the fermentation tank, due to moisture condensation If the problem cannot be eliminated in time, it will cause waterlogging of the ultrasonic probe, resulting in a decrease in measurement accuracy or even test failure.

[0003] Through the analysis of the existing technology, it is found that the advantages of using ultrasonic technology to measure gas flow are obvious (wide range ratio, small pressure resistance, and can also measure components, etc.), but there is an urgent need to solve the application of ultrasonic gas measurement technology in high-moisture gases such as biogas components. Measurement field, as well as gas flow test problems in the field of large pipe diameter, high ultrasonic energy absorption gas, etc.

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