2 replies to this topic

[hemsanjay]

Good Day everyone,

While having a throttling valve, example- a globe valve, the isolation to the globe valve is almost always in the upstream of the globe valve and not in the downstream of it.

 

For example, In most equipment draining case or a control valve bypass case, a globe valve is always followed by a ball/gate valve. what significance does the isolation valve contribute in conrolling the flow rate being in the upstream position? or is it just for the purpose of isolation without having any hard and fast rule on where it should it be located?

 

Thanks in advance.

Sanjay

[fallah]

Sanjay,

 

In drainage configuration of the liquefied petroleum gases and hydrocarbon gases the isolation valves (normally ball type) should be located upstream of the globe valve with a minimum distance of 600 mm to avoid stuck open/close of the isolation valve due to J-T effects; but may be applied to all services for simplification and uniformity.

[christopherchoa]

Here is a supporting document for Fallah's recommendation.

 

https://www.linkedin...d-rahimi-mofrad