Series with double eccentricity butterfly valves are designed for operation in very harsh environments that require high safety, trouble-free operation and minimal maintenance. The double eccentricity design ensures safe operation and tightness even with sudden changes in temperature or pressure. The purpose of the second eccentricity is to quickly relieve the seal of compression between the closing disc and the valve seat, which extends seal life and reduces torques. As the flapper closes, the rotational motion of the disc changes to linear, effectively pushing the disc into the seal space. This design also prevents unwanted accumulation of e.g. suspended solids in contact between the disc and the sealing surfaces.
Body of valves is designed to WAFER type with through holes, LUG type with threaded holes and double-flange body type with through holes. Material of disc and body consists of low carbon steel 1.1156 (A352 LCC), carbon steel 1.0625 (A216 WCB), stainless steel 1.4408 (A351 CF8M), ATEX version and TA-luft seal on request. Sealing is made by R-PTFE (PTFE reinforced by 25 % glass fibre), FIRE SAFE (R-PTFE + INCONEL), INCONEL 718 2.4668 or lamellar - stainless steel 1.4401 (AISI 316) + graphite / stainless steel 1.4462 + graphite.
