The role of the check valve is only allowed the medium to flow in one direction and prevent the medium from flowing in the opposite direction. Usually this kind of valve is operated automatically. Under the action of fluid pressure flowing in a direction, the valve petals are opened; when the fluid is flowing in the opposite direction, the self -overheating valve flap of the fluid pressure and the valve petals acts on the valve seat, thereby cutting the flow.
The classification of check valve :
According to the structure, it can be divided into three types: lifting valve, swing type valve, and butterfly -type stop valve:
1. The lifting valve of the lift -down type is divided into two types: vertical and horizontal type.
2. The swing type valve is divided into three types: single disc, dual disc and multi disc.
3. The butterfly stop valve is a direct way. The above mentioned stop valve can be divided into four types: threaded connection, flange connection, welded connection, and wafer connection form.
1. Swing type check valve:
The valve petals of the rotation -type check valve are disconnected. The rotation of the rotation of the valve seat channel is used as a rotating movement. Because the inner channel of the valve is into a streamlined type, the flow resistance is smaller than the lifting return valve. Large -caliber occasions, but it is not suitable for pulse flow, and its sealing performance is not as liter. The rotary -opening stop valve is divided into three types: single -petal, double -petal and multi -petal. These three forms are mainly divided according to the valve caliber. The purpose is to prevent the medium from stopping or turning backwards.
2. Lifting type check valve:
The disc slide back to the valve of the vertical line of the valve body. The lifting type valve can only be installed on the horizontal pipe, and the valve flap can be used on the valve flap on the high voltage small caliber to stop the valve. The valve body shape of the lifting type valve is the same as that of the deeper valve (which can be commonly used as the deeper valve), so its fluid resistance coefficient is large. Its structure is similar to the deeper valve, and the valve body and valve flap are the same as the deeper valve. The upper part of the valve petals and the lower part of the valve cover is processed with orientation. The valve petal orientation can be freely lifted in the valve -oriented simplified inner. When the medium is flowing, the valve petals are opened by the medium thrust. The vertical drop is dropped on the valve seat to prevent the aggressive effect of the medium. The direction of the direct -to -low -to -return valve medium inlet and export channels is perpendicular to the direction of the valve seat passage; the vertical lifting -down stop valve, the direction of the medium inlet and export channels of the medium is the same as the direction of the valve seat channel, and its flow resistance is smaller than the direct pass.
3. Discs check valve:
The disc stops the valve rotating the axis in the valve seat. The disc check valve structure is simple and can only be installed on the horizontal pipeline, which is poorly sealing.
1. Do not allow the check valve to withstand weight in the pipeline system. Large -scale check valve should be supported independently so that it is not affected by the pressure generated by the pipe system.
2. Pay attention to the direction of the medium flow during installation.
3. The lifting type valve of the lift vertical disc should be installed on the vertical pipe.
4. The lift horizontal disc valve should be installed on the horizontal pipe.