The high-temperature isolation valve behind the coke tower feed four-way valve will not close – please help!
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While preparing to shut off the high-temperature isolation feed water at the old tower, it was found that the isolation valve could not be closed any further once it reached 50% closure. The gears of the electric actuator were worn out, so in the end the actuator was disassembled and the shaft was forced to be closed using a clamp. I would like to ask the experienced folks if they have any other good methods for dealing with this
We have also encountered situations where even by using a clamping mechanism on the shaft, it wasn’t possible to secure it, forcing the device to enter a closed-loop cycle； The valve has to be removed for maintenance; there is no other option. The problem is usually either coking of the bellows or friction between the valve body and the valve housing.
We have also encountered this situation. When it happens, don’t panic; first reduce the amount of processing to give enough time to deal with the valve. Do not try to force the valve open or closed using external force. Instead, open and close the valve repeatedly at the location where it is stuck (patience is required). This is usually caused by coking on the sealing surface or the presence of carbon particles, and it should be quite effective.
Generally, electric drives are equipped with torque overload protection – so how could the gears get damaged?