Check valves are mainly divided into the following three types according to their structure:
- Lift check valve
The valve disc slides up and down along the vertical center line of the valve body. The forward fluid pushes the valve disc to open, and it closes by its own weight or spring force in the reverse direction. It has good sealing performance and is suitable for high-pressure small-diameter pipelines (DN≤200mm), but it needs to be installed on horizontal pipelines.
The valve disc is disc-shaped and rotates around the outer pin shaft of the valve seat. It opens when flowing in the forward direction and closes by fluid pressure and self-weight in the reverse direction. It has low flow resistance and is suitable for large-diameter pipelines (DN≥50mm). It can be installed horizontally, vertically or tilted (the medium needs to be installed from bottom to top when installed vertically).
Subcategories: single-disc type (medium diameter), double-disc type (DN≤600mm), multi-disc type (DN>600mm, to reduce water hammer).
- Butterfly check valve
The valve disc is disc-shaped and rotates around the center axis (similar to a butterfly valve). It has a compact structure and light weight, and is suitable for large-caliber and low-pressure scenarios (such as circulating water systems), but its sealing performance is relatively weak.
