Turbine flowmeter is a kind of flowmeter with high measurement accuracy. Therefore, turbine flowmeter is more sensitive to on-site conditions and has stricter requirements on working conditions and installation conditions. Users must meet its measurement conditions as much as possible during use, and correct the meter readings. When the viscosity of the fluid medium in the working state differs greatly from the viscosity of the calibration fluid, it should be corrected according to the viscosity correction curve provided by our company. Turbine flowmeters have certain requirements on the length of the straight pipe sections upstream and downstream. In this way, we should try to meet its requirements in order to maintain factory accuracy, especially when users require high precision. When the temperature and pressure of the fluid medium differ greatly from the reference conditions, the volume change of the sensor housing can be calculated according to the material and temperature and pressure of the sensor, and the meter displays the volume flow under the working conditions of the medium. To know the standard volume flow or mass flow, density compensation is also required.
The reasons for the decrease in turbine flow meter accuracy are all in common. Specifically, the decrease in accuracy of turbine flowmeters during use may be due to the following reasons:
1. Generally, there are some impurities in the medium, which will wear the bearings and shafts, increase the gap between them, destroy the dynamic balance of moving parts, reduce the rotating speed, increase the resistance of movement, or the dirt enters the gap, and the rotating speed decreases. These reasons all cause the decrease of the displayed value of the instrument and the occurrence of negative error, which is disadvantageous to the fluid supplier.
2. Changes in the fluid temperature and pressure of the flowmeter may cause the liquid in the pipeline to escape the air it contains. Or because the pressure in the pipeline is lower than the saturated vapor pressure of the fluid, part of the liquid becomes vapor. It is also possible that the outside gas is sucked into the pipeline due to the negative pressure of the medium. These gases flow with the measured liquid, causing the indicator value of the meter to increase, and a positive error occurs, which is not good for the demand side of the fluid.
3. The fibrous or viscous impurities in the fluid are attached to the rotating part of the flowmeter, which increases the resistance to rotation and reduces the indication value of the meter, resulting in negative errors, which is unfavorable to the fluid supplier.
4. The working environment is relatively harsh, such as electromagnetic field interference, high temperature, vibration, dust, humidity and so on, which may cause the malfunction or failure of the turbine flow sensor, and directly cause the indication error of the turbine flowmeter. The error is positive or negative, it may not be obvious, or it may be completely invalid. For the above phenomenon, when it is more serious, the problem can be found from the comparison of the working status of the process, so it is easy to take corresponding measures. However, in the early stage of the problem, the problem cannot be found without taking special measures.