Does all the eccentric butterfly valve is double direction seal?

[findfpso]

Dear Sir:
I have meet the problem about double eccentric valve leakage because the same pressure on outlet side of valve, so i want to know if all the eccentric butterfly valve is double side seal or not!

Thanks!

findfpso

 

[moboinc]

Hello finsfpso,

I don't know if all double-eccentric butterfly valves are tight, but i know that we produce them! We (at PCCEurovalve, Losser, The Netherlands) produce metal sealing double eccentric butterfly valves for high-pressures (up to CL600, for now) and high temperatures (up to 240 degrees centigrade). They are used in offshore-, oil-, chemical-, and watertreatment industries. They are tight-shut in both directions, and have zero-leakage.

For more info: info@pcceurovalve.nl

Regards,

Bob Schulten

 

[Cockroach]

I believe the dual eccentric butterfly valves are water tight. Your problem may be more seat related than the design issue. Check the bead on the face seal ID, she may exhibit a surface blemish causing bypass.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[ApC2Kp]

To findfpso,
Almost all of the double eccentric disk butterfly valves are capable of bubble tight shutoff in both directions for soft seats (PTFE). The maximum design shutoff pressure might be different for the direction with load on shaft/stem due to strength of shaft, compared to opposite direction with load of the disk into the body / seat retainer. This applies to wafer or lugged body valves bolted between flanges.
The seat retainer is now a weak point in the design of many lugged body butterfly valves where the user intends valve to serve in dead end shutoff. Valve seat retainers have been modified to comply with API 609, 5th edition for a gasket surface without retainer screws. This is not a problem when the valve is in flanged joint, but has only one direction full-pressure shutoff if the piping is disconnected on one side leaving valve seat against bolted flange. If the piping must be removed on the seat retainer side of valve, then the seat retainer will blow out with low pressure.
Some valve vendors offer an optional seat retained with socket head screws (old design) for full pressure dead end shutoff in both directions, but you will need to check for gasket area versus the locations of the seat restainer screws, especially when using spiral wound gaskets. The socket screws are a leak path on the gasket face of valve.