Issues with the loop valves of pigging devices
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This post was last edited by qren on 2010-8-13 at 11:58. I have a few questions regarding the connection of the pigging circuit for those who are experts: 1. If the diameter of the pipe ahead of the pig reaches 800, cannot gate valves be used? Must ball valves be used instead? 2. Are gate valves of the same diameter cheaper than ball valves? For example, by how much can 800 be reduced in price? 3. Can’t gate valves withstand pressure? The pipeline before the pig needs to be able to handle pressure, so is a ball valve the only option? If a gate valve is used for connection, the entire circuit becomes much simpler, and it seems that this can also result in cost savings. If a ball valve is used, a bypass circuit must be added next to it in order to balance the pressure. But as for whether it’s actually feasible, I would appreciate some guidance from those who are more experienced. If there are anyone who is currently using it, any practical experience they could share would be greatly appreciated
The ball valve in front of the pig should be fully open to facilitate the passage of the pig. Please consider it, OP! !
Reply to 2# lycdds: Thank you, but what I’m asking about here relates mainly to another set of pipelines and valves (the valves after the pig)
1. When the pipe diameter ahead of the pig reaches 800, gate valves can definitely be used, and they are certainly cheaper. 2. Gate valves can certainly withstand pressure without any issues. 3. There is no need in current processes to add a bypass loop alongside to balance the pressure. Because after the pig is installed, the gate valve on the pigging pipeline should be opened a few notches first; once oil fills the pigging pipeline, the pig can then be sent out.
Ball valves are not recommended when the pipe diameter reaches 800