The purpose of vent lines in dual seals?

[david6245]

Hello, I am not familiar with mechanical seals, so I apologize for my simple question.

What is the purpose of the vent lines in dual seals and gas seals? Must these seals vent continuously to flare? How much flow would be expected for a typical vent design?
Thank you,

 

[GPRnD]

API 682 will give you more information, but in general vents are there in liquid seals (for example Plan 11/53A), to allow venting and removal of gas pockets that could cause seal face damage.

Some plans such as plan 52 would be connected to a vapor recovery system and in that sense they would vent continuously. Most seal plans would only be vented prior to startup then the vents would be closed.

If you can be more specific about which seal plan you are thinking of using, it would help.