Lefoo Turbine Flowmeter

Turbine flowmeter is the main type of velocity flowmeter. It uses a multi-blade rotor (turbine) to sense the average flow rate of the fluid, and derives the flow or total amount of the meter. 

Generally, it is composed of two parts, a sensor and a display instrument, and it can also be made into an integral type. 

Turbine flowmeters, positive displacement flowmeters, and Coriolis mass flowmeters are known as the three types of flowmeters with the best repeatability and accuracy. As one of the ten types of flowmeters, their products have developed into a variety of Scale for serial mass production.

Application overview

Turbine flowmeters are widely used in the following measurement objects: petroleum, organic liquids, inorganic liquids, liquefied gas, natural gas and cryogenic fluid systems. In Europe and the United States, turbine flowmeters are second only to orifice flowmeters in terms of natural measurement. Instruments, the Netherlands alone has used more than 2,600 gas turbine flowmeters of various sizes and pressures from 0.8 to 6.5MPa in natural gas pipelines, and they have become excellent natural gas measurement instruments.

Working principle

The fluid flows through the sensor housing. Since the blades of the impeller have a certain angle with the flow direction, the impeller of the fluid causes the blades to have a rotating torque. After overcoming the friction torque and fluid resistance, the blades rotate. After the torque is balanced, the speed is stable. Under certain conditions, The rotating speed is proportional to the flow rate. Because the blade is magnetically permeable, it is in the magnetic field of the signal detector (composed of permanent magnet steel and coil). The electric pulse signal is induced, and the signal is amplified and shaped by the amplifier to form a continuous rectangular pulse wave with a certain amplitude, which can be transmitted to the display instrument to display the instantaneous flow and accumulated volume of the fluid. Within a certain flow range, the pulse frequency f is proportional to the instantaneous flow rate Q of the fluid flowing through the sensor, and the flow equation is: Q=3600×f/k

where:

f——pulse frequency [Hz];

k——The meter factor of the sensor [1/m], given by the checklist. If the unit is [1/L] Q=3.6×f/k

Q——Instantaneous flow of fluid (under working condition) [m3/h];

3600 - conversion factor.

The instrument coefficient of each sensor is filled in the verification certificate by the manufacturer, and the k value is set in the matching display instrument, which can display the instantaneous flow and cumulative total.

Common faults during operation

When the compressed air measured by the integrated turbine flowmeter is supplied in the bypass pipeline, we do not get any application in the main pipeline of the circuit we installed. I need to assemble the corresponding filter valve and filter the gas accordingly. When it is initially installed, if the valve technical data is missing or cannot be installed correctly, it will also seriously affect the measurement accuracy of the flowmeter. In addition, if we install the flowmeter upside down, so that its accumulative meter head shows downward prevention, the magnetic coupling end synchronizes the gear box, as a place for water storage, its gears and bearings are not Reasonable maintenance, and its gear part is seriously corroded, the bearing is stuck, etc., the rotor will not be able to rotate, the filter valve will appear rust, filter screen adhesion and other impurities, and the cavity of the flowmeter is blocked by residues, etc. It will lead to air supply failure and serious blockage.