single disc swing check valve

single disc swing check valve

The single disc swing check valve is also called the conventional swing check valve. In terms of the operation, its aim is also to allow the forward flow and prevent the process of reversing flow, which is just like the other types of the check valve. In briefly, the disc of the single disc swing check valve has played an important role during the whole operation. The disc would close through a long 90 degree arc with reverse flow started. Therefore, the shut off of the single disc swing check valve is significant.

The shut off depends on gravity and reverse flow. The pivot point of the swing check is outside the periphery of the disc. Thus, the greater the head, the greater the possibility that the fluid will flow back through the valve before the disc can shut off. And in order to affect complete shut off, the disc of a single disc swing check valve must travel through a 90 angle arc to the valve seat. Without resistance to slow the disc's downward thrust and forced by the reverse flow, the shut off results in slamming and damaging water hammer. Beside, the effect of the shut off can be greatly improved with addition of outside lever spring or weight or air cushion chamber, if it is necessary.