Errors and causes of correction of orifice flowmeters

During the use phase of the orifice flow meter, the process pipeline should be purged several times, and the orifice flow meter should be frequently disassembled. If the size of the orifice plate is the same, there will be an error if you do not pay attention to it, and the normal phenomenon will appear when the orifice plate flow meter is replaced. The upstream and downstream sides of the orifice flowmeter are installed upside down. During installation, it is necessary to determine the direction of fluid flow in the pipeline and the direction of the orifice flow meter, otherwise the measured value will be low. It is caused by negligence. When installing the orifice plate, place the surface marked with \"+\" on the orifice flow meter on the upstream side of the flow direction. The primary function of the pressure guide line is to transmit the differential pressure signal generated by the orifice flow meter. The laying length of the guide tube ofpressure must be between 3 and 20 meters. If the pressure guide tube is too short, the flow meter flow measurement fluctuation will become large; if it is too long, a measurement hysteresis will occur.

In the industrial production process, most gas measurements are used with the standard throttle orifice flow meter and differential pressure transmitter, although the accuracy of the differential pressure transmitter can reach 0.075 , however, for various reasons, the measurement error is also very large. When the differential pressure transmitter is used in industrial measurement, this problem will be more obvious. Therefore, it is very important to find the cause of the measurement error and the method to overcome it. The orifice flow meter is mainly composed of a pressure guide tube, an orifice plate and a differential pressure transmitter. THEorifice flow meter The throttling device component will convert the fluid flow into differential pressure, and the differential pressure will be sent to the positive and negative pressure chambers of the differential pressure transmitter diaphragm box through the guide pipeline of pressure, and the insulation diaphragm of the positive and negative pressure chambers will pass through the silicone oil The filling fluid transmits the differential pressure to the measuring diaphragm, which can cause the measuring diaphragm to shift left and right .

Surfaces upstream and downstream of the orifice flowmeter will be damaged or the orifice flange gasket will protrude into the pipeline. Damage to the upstream and downstream surfaces or the flange gasket protruding from the pipe will cause measurement errors in the flowmeter. Construction personnel should carefully check the orifice plate before installing floworifice plate meter. If the upstream and downstream surfaces of the orifice plate are damaged, they should be replaced in time. The design of the standard orifice flowmeter is achieved through a large number of experimental elements. It can be used directly without actual calibration. During the installation process, the orifice flow meter may be irregular or even wrong, which will cause flow loss. generation of measurement errors. The front and rear straight pipe sections of the orifice flow meter do not meet the requirements. The front and rear straight pipe sections must ensure the stability of the fluid flow in the pipeline. The phenomenon becomes a disturbance, which leads to an error in its measurement. The installation position of the throttle device can be reasonably designed with the front and rear straight pipe sections.

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