Wafer check valves are divided into three structural forms: lifting type, swing type and butterfly type. The swing type is divided into two types: single-flap swing type and double-flap swing type. Implementation standard: JB/T 8937-2010 Wafer check valve. American Petroleum Institute API594-2022
Wafer lift check valve models include H71 and H72.
- H71 wafer lift check valve consists of valve body, valve disc, spring and positioning plate. It is supported by a spring, but the valve disc is unilaterally guided. It is best installed on vertical pipelines, but can also be used on horizontal pipelines. Diameter≤DN350.
- H71X pumpkin type wafer silencer check valve. For use on low pressure water systems. The structural length is shorter than the H41X flange type silencer check valve. It looks like a pumpkin. Also called pumpkin-shaped wafer check valve. The valve body material is ductile iron. Can be installed on vertical or horizontal pipelines.
- The HT2H high-pressure counter valve has the advantages of compact structure, convenient manufacturing and maintenance, and reliable operation. It is widely used in high-pressure systems of synthetic nitrogen plants. It is after the threaded flange is connected to the pipe. Seal the valve with a lens gasket. Clamp the check valves in the two flanges with bolts. Nominal pressures are PN160 and PN320.
H76 wafer double-disc swing check valve.
It is mainly composed of valve body, valve disc, valve seat, torsion spring, rotating shaft, and other parts. The valve disc is composed of two semicircular valve discs. When opening, the two valve discs fold together, and when closing, the valve discs form a full circle. Closes more quickly than a single-disc swing check valve. The diameter can reach DN2000.
H74 wafer single-disc swing check valve (short series)
H74 wafer single-disc swing check valve is divided into short series and long series. The valve body length of the short series is very short, and the valve disc and pin are integrated into one body, which can just accommodate the thickness of the valve disc. It is also called a wafer thin check valve.
Compared with the flange check valve H44 of the same diameter, the weight of the valve body is greatly reduced and the size of the valve is reduced. The valve disc can be equipped with a return spring, which is used in pipelines with large pressure fluctuations to reduce water hammer.
It has two forms: hard seal and soft seal. The soft seal has a dovetail groove at the seal and an O-ring installed, making it easy to replace. The valve body flange seal can also be sealed with an O-ring to replace the flange sealing gasket, which is very convenient. Due to the product structure, the runner opening has a reduced diameter.
H74 wafer single-disc swing check valve (long series)
Compared with the H74 short series swing check valve, the long series wafer single-disc swing check valve inherits most of the features of the H44 flange check valve, such as disc, rocker arm, pin, etc. The valve body length is longer than (short series). The spring-loaded valve disc can close more quickly and strengthen the valve disc sealing.
H77 wafer butterfly check valve
The butterfly check valve rotates the valve disc around the inner pin of the valve seat, while the swing check valve rotates the valve disc around the outer pin of the valve seat. This is the main structural difference between the two.
H77 wafer butterfly check valve, the valve disc is either vertical or tilted, similar to the triple eccentric butterfly valve structure. Flange butterfly check valves are mostly used in large-diameter pipelines, up to DN2000 or above, and adopt a slow-closing structure.