Valve Controller for API Plan 54 Skid

[calgarymech]

Hello Everyone,

We have a Mallard 5450 control valves C/W Mallard 3300 pressure controller on an API plan 54 skid. The skid is used to flush the mechanical seal of a centrifugal pump. The controller senses the upstream pressure of the control valve and the control valve holds the pressure which is preset on the controller.

Our client wants this control valves to hold the pressure which is calculated by:
The centrifugal pump suction pressure + 375 kpa. (The suction pressure will change from time to time and we can take a line off the PIT at the centrifugal pump suction).

Our client doesn't want the DCS to do the calculation and send a signal to the controller. It excludes the solution to use a I/P for the control valve. We have to find a controller to get the control valve to hold a pressure 375 Kpa pressure higher than the centrifugal pump suction pressure.

It is ok to replace the control valve and controller with another device if it can perform the same function.


If anyone has thoughts on this, please let me know.

 

[pmover]

Sorry, but your question is best answer by your client. substituting equipment may not comply with the stds or specs you have been given. also, substituting equipment should be proven equipment and not experimental.

good luck!
-pmover