SWING CHECK VALVE
1.The swing check valve shall be opreated in a manner to avoid the following troubles;
1)Formation of excessive high surge pressure as a result of valve closing, and
2)Rapid fluctuating movement of valve closing member. The excessively high surge pressure by valve closing is prevented by closing the valve fast enough not to develop a significant reverse flow on a sudden shutoff which is a source of the surge pressure. Thus, the closing speed of valve should match closely with the speed of forward flow retard.
The rapid fluctuating movement of valve closing member must be avoided to prevent the moving valve parts from excessive wear which may result in early failure of valve.
Such movements can be precluded by sizing the valve to a flow rate which forces the closure member not to move.
2.The swing check valve can also be mounted to the vertical position, provied the disc should not reach the valve position. However, the closing moment of disc by weight is very low in fully-opened position, so the valve tends to close late.
In order to overcome such slow response to flow retardation, the disc may be supplied with a lever-mounted weight or with spring loaded.