Working principle and installation of gas turbine flowmeter

　　The gas turbine flowmeter is a velocity instrument that measures the flow rate of gas media in a closed pipeline. The turbine is placed in the measured gas. When the measured gas flows through the flowmeter, the turbine blades begin to rotate under the action of the gas kinetic energy. When the turbine structure is constant, the gas flow rate is proportional to the turbine speed, that is, the measured turbine speed can reflect the flow rate of the measured gas.

　　Commonly used gas turbine flowmeters generally use electromagnetic conversion devices to convert turbine speed into electrical pulses. When the fluid flows through the impeller, the electromagnetic field in the sensor changes periodically. Within a certain flow range, the speed of the turbine blades is proportional to the fluid volume flow, thereby generating an electrical pulse signal that is basically proportional to the flow. The signal is processed and enters the measurement system. After a series of calculations and corrections, the instantaneous volume flow and cumulative volume flow are displayed on the display. From the measurement principle of the gas turbine flowmeter, it can be seen that when the gas flow is lower than a certain value, the linear relationship between the flow and the speed is destroyed due to the existence of various reaction torques. Therefore, when using a practical gas turbine flowmeter, the minimum applicable flow rate is first determined.

　　Generally, the manufacturer determines the minimum metering flow rate within the accuracy range of the air medium calibration according to the structural design and manufacturing process of the product. Due to its comprehensive characteristics such as large metering flow rate, wide range, high accuracy, high sensitivity, small size, easy installation and maintenance, and low failure rate, it is suitable for accurate measurement of gas flow in gas and other industrial fields. At present, it has been widely used in the metering of urban gas. Since the gas turbine flowmeter is a velocity instrument and the metering medium natural gas is compressible, the change of pressure and temperature will lead to the change of gas density. Therefore, in the metering process, it is necessary to perform corresponding temperature and pressure compensation.

　　The gas turbine flowmeter has high precision and large flow rate. Its operating flow rate can reach over 6000m3/h. However, there is a requirement for a straight pipe section during the installation process. Currently, domestic products can shorten this straight pipe section to 2D in front and 1D in the back, greatly reducing the installation length.

　　The above is the working principle and installation of the gas turbine flowmeter provided by the gas turbine flowmeter manufacturer. You can make some references based on the above content. I hope it can help users understand more maintenance methods during use and reduce measurement errors during the use of the instrument. Regular maintenance and maintenance of the instrument can effectively improve the performance of the instrument.