316L Lift Check Valve H41W

Working Principle

Check valves are designed to allow fluid to flow in only one direction and automatically block reverse flow. Normally an automatic valve: under forward fluid pressure, the disc opens; when fluid flows backward, the combined force of fluid pressure and the disc’s own weight presses it firmly against the seat to shut off circulation.

It mainly falls into two categories: swing check valves and lift check valves.

- Swing check valves adopt a hinge structure. The disc swings freely like a door against the inclined seat surface. The hinge mechanism ensures the disc can fully open and achieve complete, tight sealing every time it closes. Discs can be all-metal construction, or fitted with leather, rubber or composite overlay sealing, customized to different service requirements. When fully open, fluid resistance is minimal with low pressure loss.

- Lift check valves have their disc seated directly on the valve body sealing surface. When inlet pressure rises, the disc lifts to allow medium passage; when flow reverses, the disc drops back onto the seat to cut off backflow. Available in all-metal design or with resilient sealing faces. Compared with swing check valves, lift type valves have a narrower flow path, larger pressure drop, and their flow capacity is relatively limited.

 Installation Types

1. Swing Check Valve

The disc is disc-shaped and rotates around a pin at the channel inlet. The internal flow path is streamlined, with lower resistance than lift check valves. Ideal for large-diameter pipelines with stable low-speed flow; not suitable for pulsating working conditions or applications requiring ultra-tight sealing. Available in single-disc, double-disc and multi-disc designs, mainly used to prevent medium backflow and reduce water hammer impact.

2. Lift Check Valve

The disc slides vertically along the centerline of the valve body. Female threaded lift check valves can only be installed on horizontal pipelines; wafer type can be used on both horizontal and vertical mounting. The valve body shares a universal design with globe valves, resulting in higher fluid resistance. When medium flows forward, pressure pushes the disc upward; upon reverse flow, the disc reseats by its own weight to block backflow. Outlet flow direction is perpendicular to the pipeline axis for lift check valves, while parallel to pipeline for swing check valves, with slightly larger flow resistance.

3. Butterfly Check Valve

Rotates around a fixed spindle at the channel center. Simple structure, can only be installed on horizontal pipelines with reliable sealing performance.

4. Wafer Lift Check Valve

Moves along the central axis of the valve body. As a new-generation product, it features compact size, light weight and optimized manufacturing craftsmanship, and is one of the fastest developing check valve types. Its fluid resistance is slightly higher than swing check valves.

5. Pressure Seal Check Valve

Specially engineered for boiler feedwater and steam turbine cut-off service. Combines the dual advantages of lift check valves and globe/angle stop valves.

In addition, there are special-purpose check valves not applicable for conventional pump outlet installation, including foot valves, spring check valves, Y-type check valves, etc.