Research Of Insertable Differential Pressure Flowmeter

As the most applied gas flowmeter, differential pressure flowmeter mainly consists of two parts: differential pressure generating device and differential pressure measuring device. The differential pressure generating devices used frequently are orifice plate, nozzle and venturi type, etc. Velocity-averaging tube flowmeter also belongs to a sort of differential pressure flowmeter. It can effectively avoid these problems and get more and more applications in the market. In order to overcome the limit that the traditional velocity-equalizing tube flowmeter ’s test-probe have to match the fluid pipe and improve the generality of velocity-equalizing tube flowmeter, this dissertation plans to design a new type of insertable differential pressure flowmeter base on structure design of the traditional velocity-equalizing tube.Through numerical simulation for the movement of fluid flow around and comparing with the traditional velocity-equalizing tube generator, this dissertation devised a new differential pressure generator called probe head. According to working principle of the velocity-equalizing tube flowmeter, put forward a insertable differential pressure flowmeter’s complete structure design. Differential pressure measuring device was the piezo-resistive differential pressure sensor of high precision. Through zero calibration and temperature drift compensation for the differential pressure sensor, improved the measurement precision of the differential pressure sensor. At the same time chose gas absolute pressure sensor and temperature sensor, mak ing insertable differential pressure flowmeter have the function of pressure and temperature measurement. Then this dissertation designed flowmeter’s hardware circuit and software part, making flowmeter more intelligent.This dissertation designed a new type of detector with good performance and developed a half- tube type insertable differential pressure flowmeter. Through the actual measurement and comparing with the traditional velocity-equalizing tube flowmeter, concluded that the new insertable differential pressure flowmeter has better versatility and can achieve high precision at the same time. This dissertation also has a certain reference value for the study of related project.