1: the indicated value reaches the maximum
When the indication value of the flow control instrument system reaches the minimum, the on-site detection instrument must be checked first. If it is normal, the failure is to display the instrument. When the on-site detection instrument indication is also the smallest, you need to check the opening degree of the regulating valve. If the opening degree of the regulating valve is zero, the regulating valve and the regulator may be faulty. When the on-site detection instrument indication is also the smallest, and the opening degree of the regulating valve is normal, the cause of the failure may be: insufficient system pressure, blocked system pipelines, unavailable pumps, medium crystallization, and improper operation. If it is a fault in the instrument, it may be that the positive pressure induced pressure conduit of the orifice plate differential pressure flowmeter is blocked; the positive pressure chamber of the differential pressure transmitter is leaking; the mechanical flowmeter is caused by a blocked gear or a blocked filter.
2: The indicated value reaches the minimum
When the indication value of the flow control instrument system reaches the maximum, usually the detection instrument also indicates the maximum. At this time, the remote control valve can be manually opened or closed. If the flow rate can be reduced, the reason may be caused by process operation. If the flow value cannot be lowered, it is the cause of the instrument system. You must check whether the control valve of the flow control instrument system is moving; whether the metering pressure measurement system is normal; whether the instrument signal transmission system is normal.
3: The indicated value fluctuates more frequently
If the indication value of the flow control instrument system fluctuates more frequently, the automatic control can be changed to manual. If the fluctuation is reduced, it may be caused by the instrument or the PID of the instrument control parameter is not suitable. If the fluctuation is still frequent, it is caused by the process operation. Cause.