Check Valves

Dual plate (double door) check valves are the preferred choice for pump discharge in most applications: spring-loaded plates begin closing before flow reversal occurs - eliminating the water hammer spike (pressure transient) that swing checks can generate when they slam shut after pump trip. Dual plate checks also have a much shorter face-to-face dimension. Swing checks are still used in low-velocity gravity drain and sewer applications, or where the low cracking pressure of a spring-free swing check is needed.

Yes, but orientation matters. Swing check valves require horizontal pipe or vertical upward flow - gravity must assist disc closure; they cannot be installed in vertical downward flow lines. Dual plate check valves (with central spring) can be installed horizontally or in vertical upward flow. Tilting disc check valves and spring-loaded lift check valves can operate in any orientation. When ordering for vertical service, always state flow direction to confirm spring tension selection.

Cracking pressure is the minimum upstream pressure differential (above downstream pressure) required to open the check valve. For standard spring-loaded dual plate check valves: 0.07–0.2 bar. For swing checks without a spring: 0.02–0.05 bar. For spring-loaded piston check valves: 0.1–0.5 bar depending on spring rating. In systems with very low differential pressure - such as gravity-flow lines or low-head pumping - always verify that the available differential exceeds the check valve cracking pressure.

Yes - dual plate check valves, tilting disc check valves, and piston-lift check valves are all available in Carbon Steel, Stainless Steel, and Duplex for gas service at high pressure. For compressor discharge service (pulsating flow), contact us for spring-selection guidance - the spring must be stiff enough to prevent valve flutter (rapid oscillation) but compliant enough to open at the available differential. API 6D compliance and all-position test certificates are provided.