O-ring seal

[gale]

Does anyone have any real data on the improvement in reliablity(if any) of a static gland seal that uses 2 o-ring seals instead of one in a low pressure (500 psi max) application

 

[troppo]

In the marine/underwater enviroment most manufactures use two o'rings in critical areas eg end caps which are opened often and single o'rings in static locations only to be replaced during regular service.
through my own experience the second o'ring has saved the day.
only my opinion know data to prove it.

 

[CM]

I have used a 2 seal design for high vacuum applications, where I otherwise would get a very tiny leak through the seal upon moving it. The space in between the two seals is pumped to a rough vacuum, thus tiny leaks past the first are pumped away before going though the secound.
You could perhaps do something similar by either having the intermeadiary space pumped, or simply to provide a small "reservoir" volume to take up any leaks before they get by the secondary seal.