Non contacting pump seals

[ghoshtathagata2000]

Hi,

Just received an offer for Eagle Burgmann seal applied in an API VS4 pump (vapour sealing - H2S). Selected seal plan is 74/61 (with N2 gas).
So far, I knew the groove patterns are always made on the mating ring which are rotating. But to my surprise, the one selected by EB is having a static mating ring.
(

https://www.eagleburgmann.com/en/pr.../gas-lubricated-seals/cgsh-k?set_language=en)

Just wondering how does the face lift off during operation if the aerodynamic element itself is fixed in place. Could anyone please explain.

 

[JJPellin]

It is common in many gas seal designs for the grooved face to be the stationary face. This lift off is accomplished by the shear of the gas between the faces. It lifts off exactly the same as it would if the grooved face was rotating. It is relative motion that drives the gas, not centrifugal force. In fact, since most of our gas seals pump the gas from the outside diameter toward the inside, any centrifugal effect would be counter to the desired flow of gas.

Johnny Pellin