The check valve works to allow the medium to flow in one direction and prevent reverse flow. Usually the valve is operated automatically, and the disc opens under the action of the fluid pressure flowing in one direction; the disc and the disc of the disc to cut off the flow.

① Domestic design standard: GB / T12236 NB / T47044 GB / T28776
Diameter and corresponding pressure range: DN15-1000 (PN16-PN100)
DN15-600 (PN16-42MPa, P54, P57 series)
② Foreign design standard: ASME B16.34 BS1868 API602
Diameter and the corresponding pressure range:
NPS½ - 40（CLASS150-600）
NPS½ - 24（CLASS900-2500）
Main materials: carbon steel, stainless steel, alloy steel
Connection type: butt welding end and flange end