two kinds of butterfly valves
The double-offset Butterfly Valve is a valve that has 2 offset compare with the concentric butterfly valve. The first offset is the shaft that located not in the center of the disk but located on slightly behind the disc. This offset will make the valve has a continuous sealing surface on the disc. The second offset is the shaft that located not in the pipe center line but located on slightly in the right side of the center. This offset will make the valve didn’t touch the seat at all when it is fully opens (see illustration below). This arrangement will make the seat experience a less friction than the concentric type butterfly valve and thus will prolong its lifetime. In typical application, this double-offset butterfly valve is limited to class 600 only.
The triple-offset Butterfly Valve is a valve that has 3 offset compare with the concentric butterfly valve. Just like the double-offset butterfly valve that has 2 offset, this triple offset also has the same offset except it has one additional offset which is a conical shape seat. This conical shape seat will match with the disc that also fabricated to match the seat. This arrangement will make the seat has no friction or rubbing while closing or opening. This arrangement will also make the valve has a bubble tight in high pressure application and much longer lifetime rather than double-offset butterfly valve. In typical application just like the double-offset Butterfly Valves, this triple-offset butterfly valve is limited to class 600 only.
More products of valves
