PP Check Valve: according to the structure division, can be divided into lift check valve, swing check valve and butterfly check valve three kinds. Lift type check valve can be divided into vertical type and horizontal type two kinds. The PPH Swing Check Valve is divided into single valve, double valve and multiple valve. PPH Ball Check Valve is a straight-through type, the above several check valve in the connection form can be divided into thread connection, flange connection, welding and pair clip connection four kinds.
PP check valve installation should be paid attention to the following matters: 1, in the pipeline do not bear the weight, large check valve should be independently supported, so that it is not affected by the pressure produced by the pipe line.2. During installation, the direction of the medium flow should be the direction of the arrow marked by the valve body.3. The lifting vertical valve check valve shall be installed on the vertical pipe.4. The lifting horizontal valve check valve shall be installed on the horizontal pipe.
PPH Check Valve refers to the valve that relies on the flow of the medium itself to automatically open and close the valve valve to prevent the medium backflow, also known as reverse check valve, check valve, reverse current valve, and back pressure valve. Check valve is an automatic valve, its main function is to prevent the backflow of the medium, prevent the pump and drive motor reversal, and the discharge of the vessel medium. Check valves can also be used to supply lines in which pressure may rise to exceed the auxiliary system pressure. Check valve can be mainly divided into rotary start type check valve (rotating according to the center of gravity) and lifting type check valve (moving along the axis).
The PP check valve functions to allow the medium to flow in one direction and in the opposite direction. Usually the valve works automatically, opening it under the fluid pressure flowing in the opposite direction, and the fluid pressure and the valve disc act to stop the valve seat to cut off the flow.
Characteristic of Wafer Check Valve:
1. The valve of the Wafer Check Valve is disc and rotates around the rotating shaft of the valve seat channel. Because the valve channel is streamlined, the flow resistance is smaller than the butterfly check valve, which is suitable for large caliber occasions with low flow rate and variable flow, but it should not be used for pulsatile flow, and its sealing performance is less than that of the lifting type. Wafer Check Valve is divided into single valve, double valve and multiple valve three, these three forms are mainly divided by the valve diameter, the purpose is to prevent the medium to stop flowing or backflow, weaken the hydraulic impact.
2. For the check valve where the butterfly-type check valve flap slides along the vertical centerline of the valve body, the internal threaded check valve can only be installed on the horizontal pipe, and the valve flap can be used on the high-pressure low-diameter check valve. The valve body of the butterfly check valve is the same in shape as the stop valve (in common with the stop valve), so its fluid resistance coefficient is large. The structure is similar to the stop valve, the body and valve are the same as the stop valve. The upper part of the valve flap and the lower part of the valve cover processing guide sleeve simple, the valve flap guide simple can be freely lifted in the valve flap guide simple, when the medium is along the current, the valve disc opens by the thrust of the medium, when the medium stops the flow, the valve disc falls on the valve seat, to prevent the reverse flow of the medium. The inlet and outlet channel of the direct through Wafer Check Valve is perpendicular to the valve seat channel; the vertical lift check valve has the same direction as the valve seat channel, and the flow resistance is smaller than that of the straight through channel.
3. For Swing Check Valve: the check valve where the valve rotates around the pin shaft in the seat. Disc-type check valve structure is simple, can only be installed on the horizontal pipe, good sealing.
4. Plastic Check Valve: the valve valve sliding along the centerline of the valve body. Pipe type check valve is a new kind of valve, its small volume, light weight, good processing technology, is one of the development direction of check valve. However, the fluid resistance coefficient is slightly larger than the rotary start check valve.
5. Compression check valve: this valve is used as a boiler feed water and steam cut-off valve, which has the comprehensive function of lifting and lift check valve and stop valve or corner valve.
In addition, there are some check valves unsuitable for pump outlet installation, such as PVC Foot Valve, spring type, Y type of check valves.