Turbine flowmeter is used to detect instantaneous flow and total integrated flow. Its output signal is frequency, which is easy to digitize. The induction coil and the permanent magnet are fixed on the housing together. When the ferromagnetic turbine blade passes the magnet, the reluctance of the magnetic circuit changes, thereby generating an induction signal. The signal is amplified and shaped by the amplifier, and sent to the counter or frequency meter to display the total accumulated flow. At the same time, the pulse frequency undergoes frequency-voltage conversion to indicate instantaneous flow. The speed of the impeller is proportional to the flow, 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 turndown 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 second.
Turbine flowmeter is the main type of velocity flowmeter. When the measured fluid flows through the turbine flowmeter sensor, under the action of the fluid, the impeller is rotated by force, and its speed is proportional to the average flow velocity of the pipe. At the same time, the blades are periodic Ground cutting of the magnetic field lines generated by the electromagnet changes the magnetic flux of the coil. According to the principle of electromagnetic induction, a pulsating electric potential signal, that is, an electric pulse signal, will be induced in the coil. The frequency of this electric pulse signal is proportional to the flow rate of the fluid being measured.
Among the various flow meters, turbine flow meters, positive displacement flow meters and Coriolis mass flow meters are the three types of products with the best repeatability and accuracy. Turbine flow meters have their own characteristics, such as simple structure and few processing parts. , Light weight, convenient maintenance, large flow capacity (large flow through the same caliber) and adaptable to high parameters (high temperature, high pressure and low temperature), etc. So far, this type of flowmeter products can reach technical parameters: caliber 4-750mm, pressure up to 250MPa, temperature -240-700℃, technical parameters like this are difficult to reach the other two types of flowmeters.
Turbine flowmeters are widely used in the following measurement objects: petroleum, organic liquids, inorganic liquids, liquefied gas, natural gas, coal gas, and cryogenic fluids. It is widely used in the transfer and gathering stations of foreign liquefied petroleum gas, refined oil and light crude oil, and the first and last stations of large crude oil pipelines for trade settlement. In Europe and the United States, turbine flow meters are second only to orifice plate flow meters for natural gas measurement. In the Netherlands alone, more than 2,600 gas turbine flow meters of various sizes and pressures ranging from 0.8 MPa to 6.5 MPa are used in natural gas pipelines.
Has become an excellent natural gas flow meter. Although the excellent metering characteristics of turbine flowmeters are favored by people, it gives people the impression that they are made of movable parts and have a short service life. They can't help but hesitate when choosing them. After people's unremitting efforts, it should be said that the situation has changed a lot. Turbine flowmeter, as the most common flowmeter, has developed into a multi-variety, full-series, and multi-specification mass production scale.