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SHUT OFF FOT ON/OFF VALVE

SHUT OFF FOT ON/OFF VALVE

(OP)
How should I determine the shut off for a full port on/off valve?

RE: SHUT OFF FOT ON/OFF VALVE

Which aspect of shutoff are you interested in ?

RE: SHUT OFF FOT ON/OFF VALVE

This is about a vague a question as you could possibly find.

No information, no data, no explanation - nothing. So no answers from me until you give a lot more.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: SHUT OFF FOT ON/OFF VALVE

(OP)
I need to determine Shut off pressure and temperature. Instrument asking for Shut off pressure and temperature.

This valve is a ball on/off valve. I do not have manufacturer data.

RE: SHUT OFF FOT ON/OFF VALVE

Shut off pressure is the pressure developed upstream of the valve if the valve is fully closed during operation. The shut off pressure will depend on what kind of equipment and process you have upstream of the valve.

For centrifugal pump, the shut off pressure is suction pressure + differential head (converted to pressure) at zero flow - see pump curve.
For positive displacement pump, the shut off pressure will be the relieving pressure on the pump discharge PSV - see pump datasheet.
For compressors, similar logic applies except that temperature rises measurably as well. This is not normally the case with liquids.
For a production well, the shut off pressure will be equal to the well shut-in pressure - talk to production operations.

Temperature in liquid service cases should not be significantly different from operating temperature, for gas service it depends on the final discharge pressure and performance of the coolers.

In case of chemical reaction upstram, blocked discharge can lead to a wide variety of scenarios - it all depends on the chemicals and processes involved.
Give us more info = you get better answers, as LittleInch says.

Dejan IVANOVIC
Process Engineer, MSChE

RE: SHUT OFF FOT ON/OFF VALVE

(OP)
The valve is on the steam supply line to turbine.
Utility steam pressure is at 170 psig, 385F.
This is a 2" ball valve at the inlet of turbine driven pumps. I have rated flow requirement but do not know the normal flow requirement. Is this something that can be obtained from the rated flow?

RE: SHUT OFF FOT ON/OFF VALVE

The shut off conditions are then equal to the maximum pressure/temperature of the supply steam.

This is full bore valve and used for isolation purpose only (= either fully open or fully closed), so there is no other flow than the rated flow. Or, put it this way, the normal flow is also the rated flow.

Dejan IVANOVIC
Process Engineer, MSChE

RE: SHUT OFF FOT ON/OFF VALVE

cheme - look at the data you have drip fed into this post and next time just put it all in the first post - makes life much better for all concerned...

EmmanuelTop has been very kind to you to answer you.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

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