D971X/D973H

Engineer's Selection Guide: Butterfly Valves

Butterfly valves are quarter-turn valves valued for compact, lightweight construction and economy at large diameters. Selection considers disc/liner material compatibility, seating type (concentric, double-offset, triple-offset), pressure class, and face-to-face standard. They suit moderate-pressure on/off and some throttling duties.

• For large-diameter water and cooling lines a concentric, resilient-seated butterfly valve is the economical default; for tight shutoff at higher pressure or temperature move to double- or triple-offset designs with a metal seat.
• In slurry or abrasive service specify a lined body with a replaceable seat — and recognize that a knife gate often fits better than a butterfly where the line must cut through settled solids.

Guidance reflects general engineering practice for butterfly valves; confirm against the project specification and applicable standards before procurement.