Quick answer: a check valve opens with forward flow and closes automatically when flow reverses, protecting pumps, compressors and headers from backflow. It is a safety and protection device, not a control device — it cannot isolate a line.
Check valve types
| Type | Flow characteristic | Typical use |
|---|---|---|
| Swing check valve | Low pressure drop, slower closing | Pump discharge, header protection, large lines |
| Lift check valve | Compact, higher pressure drop | Small lines, high pressure service |
| Dual plate / wafer check | Compact, short face-to-face | Space-limited pipework, retrofits |
| Piston check valve | Fast closing | Services where reverse flow must be stopped quickly |
Installation matters more than the valve
- Swing check valves are normally installed in horizontal lines with the cover upwards
- Flow direction must follow the arrow on the body
- Allow enough straight length upstream of the valve for stable flow
- For vertical lines, confirm the design with us before ordering
Water hammer and closing behaviour
A check valve closes when flow reverses, and the speed of that closing decides whether the line sees a pressure surge. Slower closing designs with a longer disc travel or a damped design are chosen where surge is a risk. Tell us the line size, flow rate and pump characteristics and we will advise on the type.
Testing and documentation
- Shell and seat tests before shipment
- Seat tightness confirmed to the agreed acceptance level
- Material certificate and test record shipped with the valves
待补内容位：待补：可生产口径范围、阀瓣与弹簧材质选项、试压标准、批量交期；如做止回阀与截止阀对比内容，可在此页加入内链。