Why are two flanges added to the bypass of the safety valve?
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This post was last edited by ningjingwei on 2017-4-7 at 11:05. As shown in the figure below, let’s discuss why two flanges are installed on the bypass of the safety valve – what is the purpose of that? The English explanation goes like this: In particular, a valve with a flange may not be used if the diameter of the safety valve bypass piping is less than 2 inches. It is necessary to consider installing a flange on the upstream side of the bypass valve. I’m not quite sure about this; could someone please explain it? Thank you!
It means that when the diameter of the bypass pipe for the safety valve is less than 2\", (generally, valves used for pipes with a diameter of less than 2\" are socket-type gate valves rather than flanged valves), it is necessary to install such a pair of flanges upstream of the socket-welded valve in the bypass. “Original translation: When the bypass pipe diameter of the safety valve is less than 2\", flanged valves cannot be used; it is necessary to consider installing a pair of flanges upstream of the bypass valve.” I hope the original poster can provide the best answer. Thank you!
You mean it is generally socket welding, then why are two flanges added in front of the socket-welded valve?
Easy to disassemble for maintenance. Give it a best rating** ya?:)
What do you mean? To facilitate disassembly and maintenance? Could you please explain it in detail? I heard a sound that seemed to be a seal preventing air from the safety valve from entering the flare system; I don’t understand it.
Are they project regulations, or standards? I’m not quite sure why; first of all, why not just choose valves with flange connections? Secondly, why is a live connection needed here? If it’s a blind plate or an orifice plate, it’s understandable.
This is an internal company policy; valves with flanges are not used directly, as those under 2 inches in size generally do not come equipped with flanges. Can this live connection be understood as a way to insert partitions inside in the future?
Is it used for installing blind flanges? A pair of flanges are installed upstream; when the pipe diameter is less than 2\", flanged valves are not necessary. Therefore, it is essential to consider installing such a pair of flanges upstream of the bypass – I assume they are used for installing blind flanges.
There is a sentence before this passage that says, “There is a possibility that air might be introduced into the flare system through the safety valve; therefore, temporary BPVs are installed at the safety valve and upstream of the bypass valve to prevent air contamination.””