Check valve, also known as check valve or check valve, its role is to prevent the medium in the pipeline back. Water pump off the end of the valve also belong to the check valve class. The opening and closing of the medium by the medium flow and power to open or close itself to prevent the media back to the valve called the check valve. Belonging to the automatic valve class, mainly for the one-way flow of media on the pipeline, only to allow the media to flow in one direction to prevent accidents.
Check valve structure can be divided into:
First, lift check valve:
The check valve can be mounted on a horizontal pipe along the vertical centerline of the valve body. The ball valve can be used on the high pressure small diameter check valve. The shape of the valve body of the lift check valve is the same as that of the globe valve (which can be used with the globe valve), so its fluid resistance coefficient is large.
Second, the swing check valve:
The check valve for the spool around the spool of the valve seat is more common.
Third, disc check valve:
A check valve that rotates around a pin in a seat. Disc-type check valve structure is simple, can only be installed in the horizontal pipe, the seal is poor.
Fourth, the pipeline check valve:The valve that slides along the centerline of the valve body. Pipeline check valve is a new type of valve, its small size, light weight, processing technology is good, is one of the direction of development of the check valve. But the fluid resistance coefficient is slightly larger than the swivel check valve.
Installation should note the following:
1, in the pipeline do not make the check valve to bear the weight, large check valve should be independent support, so that the pressure generated by the control 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.
Check valve working principle analysis:
The role of this type of valve is to allow only the medium to flow in one direction, and to prevent the direction of flow.Usually the valve is automatically working, in a direction of the flow of fluid pressure, the valve flap open; fluid flow in the opposite direction, by the fluid pressure and the valve flap from the valve seat in the valve seat, thus cutting the flow. The check valve belongs to this type of valve, which includes a swivel check valve and a lift check valve. The swivel check valve has a hinge mechanism, and a valve-like valve flap free to rest on the inclined seat surface.In order to ensure that the valve flap reaches the proper position of the valve seat every time, the valve flap is designed in the hinge so that the flap has sufficient swivel space and the flap is truly and fully accessible to the valve seat. The flap can be made entirely of metal, or it can be embedded in metal, leather, rubber, or synthetic coverage, depending on the performance requirements. Swing check valve in the fully open condition, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively small.
The flap of the lift check valve is located on the valve seat sealing surface of the valve body. This valve in addition to the valve can be free to lift, the rest as the same as the valve, the fluid pressure so that the valve from the valve seat sealing surface lift, the media back to the valve back to the valve seat, and cut off the flow. Depending on the conditions of use, the flap may be of the all-metal structure or in the form of a rubber pad or rubber ring in the flap frame.
Like the shut-off valve, the passage of the fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is larger than the swivel check valve and the flow of the swivel check valve is limited Very few
Check valve, also known as the counter valve, check valve, back pressure valve, check valve. Such valves are automatically opened and closed by the force generated by the flow of the medium itself in the pipeline and are of an automatic valve.
Check valve for the pipeline system, its main role is to prevent the media back to prevent the pump and its drive motor reversal, and the container medium discharge. The check valve can also be used on piping where the pressure may rise to the auxiliary system that exceeds the main system pressure.
Check valve according to the different materials, can be applied to a variety of media on the pipeline. The check valve is mounted on the pipe and becomes one of the fluid parts of this complete line. The valve opening and closing process is affected by the transient flow of the system. In turn, the closing characteristics of the valve The flow of fluid to produce a role.