Service conditions
A ball valve opens or closes the pipeline by rotating a ported ball. Port geometry, seats and stem sealing determine its operating behavior. Selection should consider differential pressure, fluid cleanliness and cycling duty together.
A pointer or scale assists position identification; the relation between position and flow still depends on internal geometry and system differential pressure. Check indicator-to-shaft correspondence, control duty and repeatability requirements.
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.