Dear Sir,

Why we Use Solenoid in Control Valves? In Our Thermal Power Plant We Have Bypassed the SOV in Control Valves which are used in HP-LP Heater's Drain System and are operated through Positioner. Is there any Condition where both Sov and Positioners are used in Control Valve?

 

Hi you all,

I supposed the SOV's have been removed or rendered inoperative.
The use of positioners and sov are common in SIS systems for boiler
controls and boiler pressure loops. Please browse on Fisher 6200 digital valve controller and functional safety assessment to the requirements of IEC61508: ed2,2010, SIL3 and SIL2.

Peter B. Macalua
Port Arthur Texas

 

> Is there any Condition where both Sov and Positioners are used in Control Valve?

Yes; there can be separate interlocks or trips that open, close or lock a control valve separately from the analogue control system using solenoid valves operated by different logic.

I have seen a solenoid valve used to position a burner control valve to a pre-light off position. After ignition the solenoid valve de-energises and releases the control valve to DCS control.