Butterfly Sealing Techniques (Metal Seat Type) 1

[CADTeach2]

I am attempting to find further information concerning the techniques for providing a consistent, repeatable, technique for a metal seat, Triple offset Butterfly valve.
Currently, I am struggling to meet API 598 for Seat Leakage, and "ZERO Leakage" descriptions are misnomers.

Specifically being tested to API 598. There is a great deal of confusing and mis-leading information concerning "ZERO Leakage". As far as design aspects, there is NO such thing as "ZERO Leakage". Every seal has some degree of leakage criteria associated with it. Even a Class VI valve, is designed to meet 12 droplets of liquid and be considered to meet the spec.
(According to FCI-70-2).
The capability of producing the cone-shaped (triple part of the offset) for these butterfly valves is not repeatable.
Perhaps I am misinterpreting the wording ZERO Leakage. Please provide input.

BLW

 

[NGiLuzzu]

CADTeach2,
I'd suggest to ask you questions in the "Valve Engineering Forum" (Forum408) within this site.

In particular, see thread408-150132 about "Zero Leakage" and all the many threads about tripple-offset metal seated valves.


Hope this helps, 'NGL