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
Lugged interfaces use body lugs and fasteners for installation. Match hole positions, threaded or through-hole form and mating flanges. End-of-line isolation or removal of one pipe side requires confirmation of the arrangement and loading conditions.
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.
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.