Check valve Wafer type double disc

The innovative dual plate design employs two spring loaded plates (disc halves) suspended on a central hinge pin. As flow begins, the plates open in response to a resultant force (F) which acts at the center of the sealed surface area. The contact point of the reacting spring leg's force (Fs) acts beyond the center of the plate area, causing the heel to open first. This prevents rubbing of the seal surface prior to normal plate opening.
As the velocity of flow decreases, torsion spring action reacts automatically. This moves the plates closer to the body seats, reducing the distance and time of travel for closure, by having greatly enhanced. This dramatically reduces the water hammer effect.
At closing, the point of spring force causes the toe of the plates to close first, this prevents dragging of the heels of the plates and maintains seal integrity for much longer periods

Valve design: API 594
Valve pressure testing & inspection: API 598
Flange connections: ANSI Class 125/150 or DIN PN16