Same as KM200 type, the drive shaft of the disc is double eccentric (double off-center). The disc and the seat do not contact until just before they are fully closed, so the seat has a long service life with little wear.

The sealing surface of the disc has a spherical surface centered around the point “O” of the figure and the seat has a clearance of the “C” on its outside. Therefore, the valve is fully closed and a uniform contact with sealing surface is obtained by simply placing the seat. In addition, the seat has a self-sealing mechanism that generates surface pressure on the seal surface of the disc by the fluid pressure, enabling a good seal from vacuum to high pressure.