How to determine if the valve spool of a control valve has fallen off?
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How to determine if the valve spool of a control valve has fallen off?
This requires taking into account the changes in the instrument parameters throughout the process; it’s a complex issue. It would be best to disassemble it when there is no load, but if it’s operating online, one can only rely on changes in the instrument parameters to make judgments. It is still difficult to judge for those processes with gas-liquid changes.
The control valve can be switched on and off manually; if it moves through its full range of motion without any change in the adjustment parameters, it can be preliminarily determined that the valve core of the control valve has fallen off.
Uncontrollable; excessive flow fluctuations and abnormal noises from the valve body
Adjust the valve position and check whether flow, pressure, and temperature fluctuate in sync
It’s very simple; there are two criteria to determine if the valve core has fallen off: 1. When fluid is flowing through the valve, metal-on-metal knocking sounds can be heard at the valve seat, which indicates this issue. Secondly, when there is a pressure gauge on the pipe section downstream of the valve, it is possible to check whether the value indicated by the gauge fluctuates, or whether it is lower than the normal pressure in the pipeline. 2. Whether the valve core has fallen off can be determined by examining the travel distance of the valve stem; generally, this travel distance is fixed and usually does not exceed 8 to 10 centimeters. If the valve stem’s travel distance exceeds the normal range, it can be assumed that the valve core has fallen off