China Double Eccentric Flange Butterfly Valve

Double eccentric sealed butterfly valve
The rotation center of disc (namely the center of valve shaft) and thecenterline ofbody form up a 'b' eccentric on the base of single eccentric butterfly valve. Makingthe sealing face of disc disengaged from seat sealing face more quickly than singleeccentric seal butterfly valves during the process of open and close. once disc turnsto8° -12°. the disc sealing face will be completely disengaged from the seat sealingface. once fully opened, a gap 'Y' will be formed up between the two sealing faces.This type of butterfly Valves are designed to have greatly lowered the mechanicalwear and extrusion deformation between the two sealing faces, making the sealingperformance of butterfly valve much better.
The characteristic of this structure is to make stem axis not only deviated from thecenter of disc. But also the center of the body. The effect of double eccentric is that,when valve has been opened, disc can be quickly disengaged from seat, thus togreatly eliminate the unnecessary excessive extrusion and scratch between the discand seat, reduce opening resistance, lower the abrasion and improve the service lifeof seat. As scratch has been greatly lowered, metal seat can be used for double eccentricbutterfly valve, so that butterfly valves are able to be used in high temperature fields.However, as its seal is positioned sealing construction ,i.e. The sealing faces discand seat is lineal contact, disc extruding seat to produce elastic deformation, thusto effect the sealing performance especially seat to produce elastic position, especiallyfor those with metal seat, and is given poor pressure endurance. This is why butterfly valves are, conventionally, not resistant to high temperature and leakage.

NoPart NameMaterialsOptional Materials1CoverCarbon Steel/Cast IronSS,Monel2BoltAlloy SteelSS,Monel3BushingPTFE+BronzeLuberized Bronze4BodyDuctile Iron/Gray Iron/Cast SteelSS,Monel5Stem2Cr13SS,Monel6DiscCast steelSS,Monel7Seal ringNBR/EPDMMBR/SS+MBR/SS+Graphite7aSeatCarbon Steel+13CrSS,Monel8PackingGraphitePTFE9BoltAlloy SteelSS,Monel10GlandCarbon SteelSS

Design StandardGB/T12238API609Pressure-Temperature RatingGB/T12224API609,ASME B16.34Face-FaceGB/T12221API609.ISO5752.ASME B16.10Flange EndsGB/T9113,JB/T79ASMEB16.5B16.47Inspection&TestJB/T9092,GB/T13927API598NorminalPressure(MPa)0.250.61.01.62.5Class150Class150Class300(MPa)
Test PressureShell Test0.3750.91.52.43.752.937.5815.0High Pressure Seat Test0.2750.661.11.762.752.075.5211.03Low Pressure Seat Test0.60.60.60.60.60.60.60.6Applicable Temperature-196ºC-550ºC
Different raw material for different work temperatureApplicable MediumWater,oil,gas and other non-causticity medium(Different raw material for different medium)