Wide application of turbine flowmeters at home and abroad
Turbine flowmeters are widely used in the measurement of petroleum, organic liquids, inorganic liquids, liquefied gas, natural gas and cryogenic fluids. In Europe and the United States, turbine flow meters are second only to orifice flow meters in terms of usage.
The turbine flowmeter first converts the flow rate to the rotation speed of the turbine, and then converts the rotation speed into an electrical signal proportional to the flow rate. This kind of flowmeter is used to detect instantaneous flow and total integrated flow, and its output signal is frequency, which is easy to digitize. The coil and the permanent magnet are fixed on the housing together. When the turbine blade passes the magnet, the magnetic resistance of the magnetic circuit changes, thereby generating an induction signal. The signal is amplified and shaped by the amplifier and sent to a counter or frequency meter to display the total integrated flow. At the same time, the pulse frequency is converted from frequency to voltage to indicate the instantaneous flow. The speed of the impeller is proportional to the flow rate, and the number of revolutions of the impeller is proportional to the total amount of flow. The output of the turbine flowmeter is a frequency modulated signal, which not only improves the anti-interference of the detection circuit, but also simplifies the flow detection system. Its range ratio can reach 10:1, and the accuracy is within ±0.2%. The time constant of the turbine flowmeter with small inertia and small size can reach 0.01 seconds.
In Europe and the United States, the turbine flowmeter is the second legal natural gas flowmeter after the orifice plate flowmeter. It has developed into a variety of natural gas flowmeters with a full range of specifications and mass production. The standard specifications are also very complete, but there are also shortcomings: the cleanliness of the measurement medium is high, and the use period is limited.
However, according to foreign use departments: 240 flowmeters that have been used for 8 to 15 years have been periodically verified and found that the accuracy of the instrument is still within the specified range. In addition, a high-efficiency rectifier rectifier is coupled with the turbine flow sensor to form a gas turbine flow meter with an integrated structure. Only 2D straight pipe length is required when the upstream side flow block is an elbow or a half-open stop valve. For the narrow installation space for urban use, it has outstanding characteristics.