3 replies to this topic

[vibhs]

Can anybody tell me the reason for providing the back to back dissimilar type check valves in a pipeline?

[kkala]

Can anybody tell me the reason for providing the back to back dissimilar type check valves in a pipeline?

I can admit "back to back" term is not quite clear to me. Moreover we place a pair of different type check valves on the pipeline to increase their (global) reliability. A pair of similar type check valves has generally higher probability of (global) failure compared to a pair of dissimilar type check valves.
Above has been found to be applicable to following cases (according to local practices):
-When eliminating backflow is critical, e.g. http://www.cheresour...__fromsearch__1, post of 24 Apr 2011 (by kkala).
-When a check valve pair exists upstream a PSV, whose discharge flow is considered reduced due to these check valves (e.g. back flow 100 m3/h without check valves, 10 m3/h with check valves installed).

Edited by kkala, 22 September 2011 - 08:07 AM.

[ankur2061]

vibhs,

Suggest you view the link below and then again look at the links in the post provided as a link to understand the the philosophy and application of two dissimiar check valves:

http://www.cheresour...__fromsearch__1

Regards,
Ankur.

[vibhs]

Thank you very much kkala and Ankur Srivastava.....Your posts have cleared my doubts and has given me insight beyond that.....