Flow Orifice in Parallel of Pressure Control Valve

S

Thread Starter

safaq

Hi,

I work in a EPC company and came across a P&ID of Nuovo Pignone Gas Turbine (not in our scope of project but was in supporting documents) and in this I found a PCV in lube oil circuit with a Flow Orifice in parallel to PCV.

A brief explanation on oil circuit. Oil from Main Lube Oil Pump get regulated (pressure not shown) then it goes through Oil Coolers and Oil Filters; and then it gets regulated again with PCV set at 1.72 barg with Flow Orifice in parallel; and then goes to Lube Oil Header.
I worked in Oil&Gas (Solar Gas Turbines) and fertilizer industry as mechanical engineer in maintenance department before this company, and this is the first time I came across this scenario. I have seen bypass valves across PCV or Two PCVs in parallel but never one with Flow Orifice in parallel. I tried searching internet before posting here but to no avail.

The only reason I can come up with is that its there to provide a minimum oil flow in case PCV gets stuck. If there is a specific reason which I am overlooking then please guide me.

Also I found same logic at Nitrogen Supply to Dry Gas Seal. PCV with Flow Orifice in parallel after filters.

Since it was in supplementary documents I do not have any other information on GT like model, make etc.

Thank you
 
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