Dual Plate vs Swing Check Valve
Dual-plate check valves use spring-assisted plates with shorter travel, while swing check valves use a hinged disc that moves through a larger arc.
Those mechanisms create different pressure loss, closing response, installation length, orientation sensitivity and transient behavior in the piping system.
The comparison should use actual flow velocity, line size, fluid density, orientation, available straight pipe and water-hammer risk rather than choosing only on face-to-face length.