Turbine flowmeter is the main type of velocity flowmeter. When the measured fluid flows through the turbine flowmeter sensor, the impeller is forced to rotate under the action of the fluid, and its speed is proportional to the average flow rate of the pipe. At the same time, the blade periodically cuts the magnetic line of force generated by the electromagnet, changing the magnetic flux of the coil. According to the principle of electromagnetic induction, a pulsating potential signal, that is, an electric pulse signal, will be induced in the coil, The frequency of this electric pulsation signal is proportional to the flow rate of the measured fluid.

characteristic

Turbine flowmeter has the advantages of high precision, good repeatability, zero drift free, high range ratio, etc. The turbine flowmeter has high-quality bearings and specially designed deflectors, so it greatly reduces wear, is insensitive to peak values, and can provide reliable measurement variables even under harsh conditions. The output signal of turbine flowmeter is pulse, which is easy to digitize. The turbine flowmeter has small pressure loss, its blades can be anti-corrosion, and it can measure viscous and corrosive media.

type

1. Axial type, the center of impeller shaft coincides with the pipe axis, which is the main product of turbine flowmeter.

2. Tangential type, the impeller shaft is perpendicular to the pipeline axis, and the incidence angle of fluid flow to the blade plane is about 90 degrees. It is suitable for small diameter micro flow measurement, and plug-in tangential turbine flowmeter is also used for large diameter flow measurement.

3. Mechanical type. The rotation of the impeller directly or through magnetic coupling drives the mechanical counting mechanism to indicate the total amount of integration. The measurement accuracy is slightly lower than that of the electrical signal detection sensor. The turbine flowmeter and display device are integrated.

4. The downhole special type is applicable to the downhole operation of oil exploitation. The measuring medium includes mud, oil and gas flow, etc. The volume is limited, and it needs to be resistant to high pressure, high temperature and fluid impact.

5. Self correcting twin turbine type, which can be used for gas flow measurement such as natural gas. The sensor is composed of main and auxiliary double impellers, and the change of flow characteristics can be automatically corrected by the speed difference between the two impellers.

6. Wide viscosity type, based on the Porter type floating rotor pressure balance structure, the diameter of the upper cone and the lower cone is expanded, and structural measures such as viscosity compensation wing and pressure bearing blade are added to make the sensor suitable for high viscosity liquids.

7. Plug in turbine flowmeter consists of measuring head, insertion rod, insertion mechanism, converter, instrument, etc.

In a word, turbine flowmeter can be divided into axial turbine flowmeter and tangential turbine flowmeter according to its structure. At present, axial turbine flowmeter is widely used, while tangential turbine flowmeter is rarely used. However, tangential turbine flowmeter has some characteristics that axial turbine flowmeter does not have, such as lower measurement limit, higher measurement sensitivity and faster dynamic response.