Long neck type short neck type and neckless type are available for versatile applications. Optionally available NECK Mounting Kits enable easy change of valve necks to other type, depending on service conditions: (Valves need to be dismantled from pipelines for neck replacement.)

Light weight of die-cast aluminum valve body (which is only one-thirds of KITZ's conventional cast iron butterfly valves) eases valve-to-flange centering work on mounting valves on pipelines.

Austenitic stainless steel discs and EPDM rubber seats can handle many different kinds of line fluid without concern of corrosion.

A pair of stem bearing assembled around the top and bottom stems prevents stem galling, and stabilizes valve operating torque for smooth and trouble-free disc rotation.

The actuator mounting pads of all necks are designed in conformity with ISO 5211 requirements for direct on-site mounting of actuators which are provided with ISO 5211 valve mounting flanges.

Along stainless steel neck blocks transfer of the fluid heat to a valve operating device, which thus needs no insulation. Dew condensation is minimized also in case of cold water service.

Main parts such as stems, discs, necks, neck connectors and boltings are all made of stainless steel for highly graded rust prevention.

KITZ's original cross-sectionally S-shaped valve discs with spherical surface evenly make tight contact with rubber liners for excellent sealing performance with reduced operating torque. Thorough 360° shut-off mechanism helps extend service life of rubber liners.

* The structural drawing shows a size 100A valve.

The disc uses a globe-shaped face developed by KITZ and an S-shaped disc. When the valve is closed with light torque, the entire face contacts the seat evenly, providing a superior seal. The simultaneous full circumference shutting feature has also contributed to significant improvement in seat durability.

Molded-in (bonded) seat structure is employed for size 2" to 12". Larger sized valves are provided with replaceable seat. This non-peeling seat-to-body construction assures maintenance-free application for high fluid velocity service*1, vacuum service*2 and handling surging fluid velocity. It also guarantees peel-free valve mounting on pipelines.

Rubber seats are spherically designed where they contact top and bottom stems. This protects widely designed rubber seats from peeling or deformation for prolonged service life of valves. Thinly streamlined metal discs are the results of elaborate laboratory study to ultimately minimize the pressure loss.

Choice among 4 disc and 2 seat materials and manual, pneumatic or electric valve operating devices makes service applications highly versatile.

Any pneumatic or electric valve actuators provided with ISO 5211 valve mounting flanges can be easily mounted for actuation of valves in the field.

Low operating torques are designed low for extension of valve service life and economic consideration in selection of valve operating devices.

Designed much lighter than our conventional series for operation efficiency in piping.

Prevention of external fluid leakage is maximized with a rubber O-ring assembled around the top stem and tight contact between spherically designed rubber seat and spherically designed top and bottom end of the disc.

Dew condenstation prevention type is optionally available with heat.

The valves stem is designed eccentric to both the center of the seat ring (by X) and the center of the valve body (by Y), which makes the clearance C between the seat ring and the disc seat surface on its fully open position (Fig.1). Disc seating surface is spherically machined and contacts PTFE seat tightly thorough 360�Ž for leak-free service. All these help minimize frictional wear of seat rings and reduce the valve operating torque considerably.

Seat rings are made of PTFE with stainless steel supporter. Furthermore, double-eccentric kinematics relieve seat ring from damage or wear which is a rather usual problem of conventional butterfly valves, This makes the service life twice as long as rubber seated butterfly valves.

There is a room between the gland and the lever or gear to allow retightening of gland boltings without trouble of disassembly of the lever or gear during plant operation. Another feature of KITZ Type UB butterfly valves (Fig.2).