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Pig launcher and receiver valve selection?
- Thread starter antoil
- Start date
Yes, a full-bore ball valve is considerably better than a gate valve for the barrel isolation valve on a launcher or receiver. These valves are operated frequently (hopefully) and the 80 or so turns required to operate an 8-inch gate valve will not make you popular with the operations guys.
Further, I always specify trunnion ball valves for the barrel-isolation valves (over floating ball valves) because they give you two seating surfaces between the line pressure and the trap - it can be a real pain if the barrel-isolation valve leaks through while you are trying to launch a pig.
David Simpson, PE
MuleShoe Engineering
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
The Plural of "anecdote" is not "data"
Further, I always specify trunnion ball valves for the barrel-isolation valves (over floating ball valves) because they give you two seating surfaces between the line pressure and the trap - it can be a real pain if the barrel-isolation valve leaks through while you are trying to launch a pig.
David Simpson, PE
MuleShoe Engineering
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
The Plural of "anecdote" is not "data"
- Thread starter
- #3
I've used actuated and gear-operated both and below 16-inch I find the actuators to be a pain (leaks, freezes, difficulty dealing with low pressures if you pull the system pressure down, etc.).
The sequence I require for launching valves is (starting with the trap isolated and blown down, see my web page under "Samples" "Rules of Thumb for Gathering Equipment" for a description of what I think should go into a launcher design):
1. Load pig
2. Open kicker
3. Open barrel-isolation valve
4. Shut side valve
5. Re-open side valve after pig has left
6. Shut barrel-isolation valve
7. Shut kicker and blow barrel down.
With that sequence you never have any dP across the big valves so I think an actuator is a waste of money and an addition of unnecessary complexity.
David Simpson, PE
MuleShoe Engineering
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
The Plural of "anecdote" is not "data"
The sequence I require for launching valves is (starting with the trap isolated and blown down, see my web page under "Samples" "Rules of Thumb for Gathering Equipment" for a description of what I think should go into a launcher design):
1. Load pig
2. Open kicker
3. Open barrel-isolation valve
4. Shut side valve
5. Re-open side valve after pig has left
6. Shut barrel-isolation valve
7. Shut kicker and blow barrel down.
With that sequence you never have any dP across the big valves so I think an actuator is a waste of money and an addition of unnecessary complexity.
David Simpson, PE
MuleShoe Engineering
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
The Plural of "anecdote" is not "data"
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