Check valve can be divided according to its structure and installation method:
1. Swing check valve
Swing back valve is in a disk shape, and the channel around the seat of the shaft for rotation, because the valve channel into a streamlined, flow resistance than check lift back valve used in low flow rate and flow does not often changes in large caliber occasions, but not for the pulsating flow, the sealing performance is less than lift. Swing check valve sub unicuspid type, double valve type, and most of type three, three by the valve diameter to form the main points to in order to prevent the media to stop the flow, or reflux, the weakening of the hydraulic shock.
2. Lift check valve
Valve flap along the vertical centerline of the valve body sliding check valve, lift check back valve can only be installed in horizontal pipelines, ball of small-diameter high-pressure check valve on the valve flap can be used. Lift check valve body shape and the same cut-off valve (can be common with the cut-off valve), so it is a larger coefficient of fluid resistance. Its structure is similar to the cut-off valve, the valve body and the valve flap are the same as the cut-off valve. The upper part of the valve and the valve cover the lower part of the processing of a simple guide sleeve, valve guide Jane can the free valve simple light driven movements, when the medium downstream, the valve flap by the media thrust open, when the media stopped flow, the valve by self - vertical landing on the seat, to prevent the media from the upstream role. Straight lift check valve media import and export channel perpendicular to the direction of channel direction and the valve seat; vertical lift check valve, the media import and export channel channel direction and the valve seat in the same direction, the flow resistance is smaller than the straight through.
3. Disc type check valve
Valve flap around the valve seat of the shaft rotation of the check valve. Disc check valve structure is simple, can only be installed in the horizontal pipe, poor sealing performance.
4. Pipe type check valve
Valve to slide along the center line of the valve body. Pipe type check valve is a new type of valve, it has a small size, light weight, good processing technology, is one of the development direction of the check valve. But the fluid drag coefficient is slightly larger than the swing check valve.
