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Process condition for On/Off valve.

Process condition for On/Off valve.


I have a data sheet of a On/Off valve. The valve is intended to be operated for N2 gas.
The downstream of the valve get mixed with the process liquid.
But the data sheet contains process condition(fluid properties) for liquid instead of gas.
Both fluid process conditions are different at upstream and downstream of the valve.

Is data sheet containing wrong process data?

I really don't have any idea about this type of feature.

Would be very grateful for getting any help.

Many Thanks.

RE: Process condition for On/Off valve.

Is this a data sheet for a valve yet to be purchased or the data sheet for an existing installation? Would the valve contact the downstream liquid?

RE: Process condition for On/Off valve.

Dear jari001,

You are right. The valve is yet to be purchased and it will contact with the downstream liquid.


RE: Process condition for On/Off valve.

If I understood correctly, the valve is specified for liquid service whilst it will actually operate in gas service?

Without knowing any additional information, it appears highly unlikely that the valve will be able to perform its intended function. Please post a sketch and valve parameters and we may be able to provide you with more specific answers.

Process Engineer, MSChE

RE: Process condition for On/Off valve.

Dear EmmanuelTop ,

Thanks for your concern in this matter.
You are right about your concept.
I have added pdf file which contains 2 possible figures and the data sheet for V-2 valve sizing.

For figure-1, V-3 valve data sheet contains inlet N2 fluid properties for valve sizing.
The problem is associated with figure-2.

Many Thanks.

RE: Process condition for On/Off valve.

The query now turned into something different, but I think I understand your question.

The On/Off valve is a part of the Nitrogen system - fluid service is Nitrogen and the valve body material matches with the piping class for Nitrogen service. Datasheet should reflect this information - fluid should be Nitrogen, not "process liquid".

Figure 2 is technically incorrect from the point of view of current design (if SS304/316 is susceptible to process fluid, it can be damaged). With the arrangement as in Figure 1, that possibility is significantly reduced (but not eliminated, due to common leakage of check valves).

Process Engineer, MSChE

RE: Process condition for On/Off valve.

Thanks EmmanuelTop for sharing your view.

The truth is that I have both arrangements in my design.
If SS304/316 is susceptible to process fluid, then should V-2 be sized for CS11 and process liquid despite being the part of N2 system?


RE: Process condition for On/Off valve.

Not really "sized for liquid" because it will pass Nitrogen when opened, but the material selection should be based on compatibility with Nitrogen and liquid phase downstream of the valve.

Process Engineer, MSChE

RE: Process condition for On/Off valve.

I agree with EmmanuelTop's input. I personally would try to include the potential process fluid(s) in the data sheet as a record of acknowledging that even though the valve is intended only for N2 service, some special considerations were taken in specifying the valve; this helps preserve your line of thought for yourself in the future and/or others that will have to work on the system without the benefit of your memory.

RE: Process condition for On/Off valve.

It was a very good consideration from EmmanuelTop for selecting compatible material for both fluids.

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