2 replies to this topic

[ogpprocessing]

Dear CHE Experts,

I have seen at some AFC P&IDs that ball valve has been used for nitrogen generation packages and distribution lines.

Is there any specific reason for that? Can we use other cheaper valves such as gate valve for nitrogen service?

[Art Montemayor]

You can use what ever type of valve that you so desire. There is nothing to prevent you with the exception of your supervisors, company standards, local regulations, and safety concerns.

I would expect a gate valve to be more expensive than a ball valve. Even my local hardware store no longer stocks gate valves. Every water and gas valve in my home (and in my neighborhood, I believe) is a ball valve type. And that is so because they are cheaper - not because I am forced to use them.

A specific reason for using a ball in a process (over a gate valve) is because of bubble-tightness - especially in any gas service. Ease of opening and closing with a quarter turn and attaching a simple actuator are other important reasons. Ball valves do not require the head room that gates do. Besides all of the above, I like them.

[GS81Process]

Quarter turn ball valves have a potential of being inadvertently opened or closed if they are in a high traffic area. This can occur either by bumping, catching on loose coveralls, etc.

It is wise to evalulate their location and have them locked in position if there is a hazard resulting from their being accidentally opened or closed.

Edited by GS81Process, 04 September 2012 - 05:53 PM.