Concentric Resilient-Seated Wafer Butterfly Valve

Service conditions

A butterfly valve changes the available flow area as its disc rotates about the stem. Its compact rotary arrangement is widely used for pipeline isolation. Flow-control duty also requires assessment of disc position, differential pressure, flow response and actuator control capability.

Construction and description

In a concentric butterfly valve the disc axis passes through the flow-passage center and the disc edge engages a resilient seat. Consider seat deformation, edge contact and pipe bore, with enough clearance for the disc to rotate fully.

Service conditions

A resilient seat seals through contact and deformation where it meets the disc. Match the seat material to the fluid, temperature and cleaning conditions. Aging, swelling and trapped particles can affect operating torque and the sealing surface.

Construction and description

Match the operator to the valve load and site operating method. Manual operation needs accessible clearance. Frequent cycling or remote control also calls for assessment of output capability, duty and position feedback.

Wafer installation places the valve between mating flanges. Check flange standard, pipe bore, bolt arrangement and clearance for moving internal parts. Additional gasket requirements depend on the seat and connection design.

Define fluid composition and continuous and start-stop operating conditions, then assess body, internals and seals as a combination. Particles, deposits and cleaning affect sealing surfaces and mechanisms; plan maintenance for the actual service.