The opening and closing of the medium by the flow of power to open or close itself to prevent the media back to the valve called the check valve. Check valve is an automatic valve, mainly for the media on the one-way flow of the pipeline, only to allow the media to flow in one direction to prevent accidents. Check valve by structure, can be divided into lift check valve, swivel check valve and butterfly check valve three: 1. Lifting check valve is divided into vertical and horizontal two. 2. Swing check valve is divided into single-valve, double-valve and multi-valve type three. 3. The butterfly check valve is straight type. More than a few check valves in the form of connection can be divided into threaded connection, flange connection, welding connection and folder to connect four.Check Valve
Check valve: According to the structure, can be divided into lift check valve, swivel check valve and butterfly check valve three. Lifting check valve can be divided into vertical and straight type two. Swing check valve is divided into single-valve, double-valve and multi-valve type three. Butterfly check valve is divided into butterfly double petals, butterfly single flap, more than a few check valves in the form of connection can be divided into threaded connection, flange connection, welding and folder to connect four. Check the installation of the check valve should pay attention to the following: 1, in the pipeline system do not let the check valve to bear the weight, large check valve should be independent support, so that the pressure generated by the pipeline system. 2, the installation of attention to the direction of media flow should be consistent with the direction of the valve body arrow. 3, lift vertical valve check valve should be installed in the vertical pipe. 4, lift the level of the valve check valve should be installed in the horizontal pipe.
The structure of the lift check valve is generally similar to the cut-off valve, the valve flap along the middle of the channel for lifting movements, reliable action, but the fluid resistance is large, suitable for smaller caliber occasions. Lifting check valve can be divided into straight and vertical two. Straight-through lift check valves can only be installed in the horizontal pipe, and vertical lift check valve is generally installed in the vertical pipe.
The flap of the swivel check valve is used for rotary motion. Its fluid resistance is generally less than the lift check valve, it is suitable for larger caliber occasions. Swing check valve according to the number of discs can be divided into single-swivel, double-flap and multi-flap open three. Single flap check valve is generally suitable for medium caliber occasions. Large diameter pipe selection single flap check valve, in order to reduce the water hammer pressure, it is best to reduce the water hammer pressure slow closing check valve. Double flap check valve for large and medium diameter pipe. The double-flap-type check valve has a small structure and a light weight. It is a fast-acting check valve. The multi-flap check valve is suitable for large diameter piping.