FinFan Shoulder Plug Gaskets

[rzrbk]

Our refinery has always used solid metal gaskets to seal fin fan shoulder plugs. (threaded plugs in header boxes of air cooled exchangers) Proper preparation of the machined sealing surface has always been a problem when reassembling these exchangers.

I would like to look at going with grooved metal, graphite covered gaskets which may be more forgiving of flaws in the machined sealing surface. These are now available from several companies.
The concern is that these plugs have very little free length or stretch to account for any relaxation that may occur in the graphite, which might cause leaks after start-up.

Does anyone have experience with retrofitting fin fans with GMGC plug gaskets?

Thanks

 

[gasketguru]

I'vs supplied kammprofiles for fin fan header plugs in the past about 29 x 35mm from memory), so rather narrow and thus you only get a few "teeth" on the kamm face. There is the risk of shearing the thin, narrow graphite layers at first, but usually and with a little care it all gets compressed into the teeth of the gasket and seals minor imperfections on the mating faces - better than the old soft iron washers at least.