The check valve refers to a valve that actively opens and closes the valve flap by means of the mediums own activity, and is used to prevent the medium from flowing backward, and is also called a check valve, a check valve, a reverse flow valve, and a back pressure valve. The check valve is attributed to an active valve whose primary effect is to avoid backflow of the medium, to avoid reverse rotation of the pump and drive motor, and to vent the container media.
The check valve can also be used to supply a line in which the pressure may rise to an auxiliary system that exceeds the system pressure. The check valve can be divided into a swing-type check valve (rotation according to the center of gravity) and a lift check valve (moving along the axis). Check Valves The effect of this type of valve is to only allow the media to move in one direction and obstruct the opposite direction. Usually, the valve is actively operated, and the valve flap is opened under the action of the fluid pressure in one direction; when the fluid moves in the opposite direction, the valve pressure is applied to the valve seat by the fluid pressure and the valve disc, and then the activity is cut off. The check valve is attributed to this type of valve, which includes a swing check valve and a lift check valve. The swing check valve has a hinge mechanism and a valve flap of the same door freely rests on the surface of the skewed seat. In order to ensure that the valve flap can reach the proper orientation of the valve seat surface each time, the valve flap is designed in the hinge mechanism, so that the valve flap has a swinging space and the valve flap is truly and comprehensively touched with the valve seat. The disc can be made entirely of metal, or it can be inlaid with leather, rubber, or a component covering, depending on the performance requirements. With the swing-open check valve fully open, the fluid pressure is simply unobstructed and the pressure drop across the valve is relatively small. The valve flap of the lift check valve is located on the valve seat sealing surface of the valve body. In addition to the valve flap being free to lift and lower, the valve is similar to the same as the shut-off valve. The fluid pressure causes the valve flap to lift from the valve seat sealing surface. The return of the medium causes the valve flap to fall back to the valve seat and cut off the activity. Depending on the application conditions, the valve flap can be an all-metal construction or a rubber or rubber ring on the valve disc holder. Like the stop valve, the passage of fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is greater than that of the swing check valve, and the flow of the swing check valve is constrained. Very few.
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Resin sand casting, etc.
Check valve test condition: the lift check valve disc axis is in a straight position with the horizontal; the swing check valve passage axis and the flap axis are in an orientation approximately parallel to the horizontal line.
In the strength test, the experimental medium is introduced from the inlet end to the specified value, and the other end is closed, and the valve body and the valve cover are not leaked.
The sealing test was carried out from the outlet end, and the sealing surface was inspected at the inlet end. No leakage at the packing and gasket was qualified.