Swing check valve. In swing check valves, the disc is unguided when it moves to fully open position or to fully closed position. Many different disc and seat designs are available to satisfy requirements of varying applications. Soft-seated– swing check valves provide improved leak tightness compared to metal-to metal seating surfaces. Combination seats consisting of a metal seat ring with resilient insert also offer better leak tight characteristics. The seating angle, the angle between the seat and the vertical plane, may vary from 0 to 45 degrees. Vertical seats have a 0 angle. Larger seat angles reduce the disc travel, resulting in quick closing, thus minimizing the possibility of water hammer. Usually the seat angles are in the range of 5 to 7 degrees.
- They are self-actuated and require no external means to actuate the valve either to open or close. They are fast acting.
The following are some of the disadvantages that are attributed to check valves:
- Since all moving parts are enclosed, it is difficult to determine whether the valve is open or closed. Furthermore, the condition of internal parts cannot be assessed
- Each type of check valve has limitations on its installation configurations
- Valve disc can stick in open position
- Process
- Mining
- Food & Beverage
- Oil & Gas
- Pharmaceutical
- Power
The specific use of a check valve depends on the configuration of the component. For example, lift and ball check valves must always be placed so the direction of the lift is vertical. However, swing check valves must be placed to ensure the disc is always closed freely and positively by gravity.
