Turbine flow meter principle

What is the principle of the turbine flow meter? What constitutes it and how it should be selected? Many people consult the relevant knowledge about the turbine flow meter. We have made relevant explanations and explanations on these issues.

Turbine flowmeter consists of turbine, bearing, preamplifier and display instrument

The measured fluid impinges on the turbine blades and causes the turbine to rotate. The rotational speed of the turbine changes with the flow rate, that is, the flow rate is large, and the rotational speed of the turbine is also large. Then, the rotational speed of the turbine is converted into the electrical pulse of the corresponding frequency by the magnetoelectric conversion device. After the preamplifier is amplified, it is sent to the display meter for counting and display. The instantaneous flow rate and the accumulated flow rate can be calculated based on the pulse number and the accumulated pulse number in the unit time.

The working principle of the turbine flow meter is that when the fluid flows along the axis of the pipeline and strikes the turbine blades, a force proportional to the product of the flow qv, the flow velocity V, and the fluid density ρ acts on the blades to rotate the turbine. While the turbine is rotating, the blades periodically cut the magnetic lines of force generated by the electromagnets and change the magnetic flux of the coils. According to the principle of electromagnetic induction, a pulsed potential signal will be induced in the coil. The frequency of this pulse signal is proportional to the flow of the fluid being measured.

The pulse signal output by the turbine flowmeter is amplified by the amplifier and sent to the display meter to measure the flow rate.

Turbine flow meter selection

(1) The flow meter body is preferably treated with 316 stainless steel for corrosion protection in the selected area. If it is an explosion-proof area, it must also be an explosion-proof result.

(2) Bearings usually have carbonized tungsten, polytetrafluoroethylene, carbon graphite three kinds of specifications: the highest accuracy of tungsten carbide, it is used as a standard part of industrial control; PTFE, carbon graphite can be anti-corrosion, generally preferred in chemical industry places . The square of the bearing life flow rate is positive and negative, so the best flow rate is 1/3 of the maximum flow rate.

(3) The sensing probe detects the movement of the rotating body and converts it into a pulsed digital electrical signal. Its output voltage of the electromagnetic coil is close to a sinusoidal curve. The frequency range of the pulse signal varies linearly with the measured flow rate. The typical range is 10 : 1,25:1 and 100:1 three specifications. The resistance of the solenoid coil is generally less than 2000Ω, and if it is larger than this value, it may be damaged.