magnetrol displacer control valves

[barry1982]

We use a magnitrol level controller on one of our hydrocarbon knock out vessels. It seems when the ambiant temperature gets lower than 0C the valve won't operate properly. The displacer float cage is clean, so does the cold ambiant temperature have an effect on the magnet itself causing it not work?

 

[Ashereng]

Have you checked the dew point of your instrument air? I am guessing that you are freezing in your I/A line, regulator, actuator?

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[barry1982]

The rest of our control valves work fine so I dont think thats the problem.

 

[25362]

Is there a possibility of a rubbing interaction between the float and the chamber at lower temperatures ? Rubbing might bring about the transferring of magnetic properties to the non-magnetic metal of the chamber guide resulting in wrong level signals.

 

[instrument1717]

Hope You have a displacer type level instrument ,a level controller at DCS for level control and a control valve on line.

It can be a problem at low ampient Temperature ( It happenes very rarely )
1. with electronics circutry of level controller or
2. with electronic circuite of i/p convertor(or
Electropneumatic positioner.)
Is there any control scripts (Related to other Plant variables )are assosciated with this controller in System ?.

Instrument1717