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There are many types of check valves: including swing check valves, lift check valves, spherical check valves, piston check valves and disc-type separation check valves. In this case, the fully open swing check valve is suitable for most non-fluctuation situations. Rotary start check valves are also used in vertical pipelines (flow direction upwards). And at this time, there is a stop block in the valve to prevent the valve flap from opening beyond the top dead center.

In vertical pipelines, the swing check valve cannot be used for downward flow. If used under low fluctuations and low flow rates, the swing check valve will vibrate and eventually damage the sealing surface. In order to improve its service life, the valve disc can be coated with stellite. In order to reduce the leakage of 2-position 3-port solenoid valve seat, elastic seal should be adopted. The detachable valve seat should be preferred because they are easy to maintain and can easily replace the valve seal.

Swing check valve should choose screw or bolt connection bonnet to check and repair the disc and valve seat. The high-pressure swing check valve can be repaired in the pipeline. In many cases, its minimum diameter can be DN65 (2.5NPS) or DN80 (3NPS)

A thin rotary check valve (space saving), suitable for installation between the two flanges of the solenoid valve manufacturer. This type of check valve is not fully opened under normal conditions and needs to be removed from the pipeline during maintenance.

The double-disc single-plate check valve occupies a small space and is light in weight, and is often used in offshore oil. The double-disc thin check valve cannot be used for pulse operation because fatigue can cause the spring to fail. However, consider the use of non-impact or rotary check valves.