Differential pressure liquid level gauge fault judgment
The device that uses the liquid column to generate pressure to measure the height of the liquid level is called a differential pressure liquid level gauge, a differential pressure transmitter, a double flange differential pressure transmitter, a single flange liquid level transmitter and an input liquid level transmitter. Transmitters are common differential pressure liquid levels, and this article focuses on them. The change speed of the liquid level parameter is closely related to the volume of the container, so it should be judged according to the actual situation whether the change speed of the liquid level is normal. For example, the water level of the boiler drum (a differential pressure transmitter is commonly used to measure the water level of the drum) changes quickly, but the liquid level of the liquid storage tank changes slowly. There are sudden large changes and fluctuations in the liquid level display, such as indicating the maximum or minimum, the possibility of failure of the differential pressure liquid level gauge is very high.
When the display value of the liquid level reaches the maximum or minimum, the differential pressure liquid level gauge should be checked first. If the transmitter is normal, most of the display instruments are faulty. If the output of the transmitter is consistent with the display of the display instrument, the liquid level control system can be changed to manual operation, that is, the opening of the regulating valve can be manually changed to observe whether the liquid level has changed. The change of the liquid level is generally caused by the process. If there is no change, the differential pressure level gauge is faulty.
When the liquid level record curve fluctuates greatly and quickly, it may be that the PID parameters of the regulator are not set properly, or the parameters have changed. The damping of the differential pressure liquid level gauge is not adjusted properly, and the leakage of the pressure guiding pipeline may cause fluctuations in the liquid level recording curve.
The most feared thing about measuring liquid level is false liquid level. If you suspect false liquid level, you must judge calmly. The control system can be switched to manual operation, and then the differential pressure liquid level gauge and the system can be checked or corrected, and all pressure guiding pipelines and valves can be checked for problems, so as to find out the problem directly.
