Keystone API 6D Swing Check Valve 4" 150 Class

Engineer's Selection Guide: Check Valves

Check valves permit flow in one direction only and protect systems from backflow. Selection balances the type (swing, lift, dual-plate, tilting-disc) against pressure, flow velocity, and space. Sizing to avoid chatter and confirming the cracking pressure are essential for reliable operation.

• On pump discharge a swing check with a counterweight or dashpot damper reduces slam and water hammer; where space or vertical-up flow prohibits a swing check, use a spring-loaded dual-plate or silent check.
• For steam and condensate use a tilted-disc or piston check to resist chatter at low flow better than a standard swing check, and always confirm the minimum cracking pressure against the system backpressure.

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