A Failure Case of Level Switch/transmitter that controls a solenoid operated valve

Here is a failure case that the level switch tripped and the valve closed when the Level was still above the setted lower level point. The level switch is supposed to trip when level gets lower than the setted point and have the valve close.

This failure would happen when vessel vapor temperature is higher than the minimum ambient. If so, the vapor leg should be remote sealed to prevent saturated vapor from getting into the vapor leg of the level transmitter.

We UTOP have level sensors like ULB7 corrosive proof level transmitter, ULB9 small size level transmitter for you to choose. 

Any interest, feel free to contact Stella Meng.