Check valve is relying on the flow of the medium itself and automatically open and close the valve flap, used to prevent the medium backflow valve. The role of the check valve are: to prevent backflow of media, to prevent the pump and drive motor reversal, as well as the container medium discharge.
1, check valve can prevent the media backflow:
Check valve only a flow direction, that is, only along the direction of the inlet flow, to prevent the water flow in the opposite direction. Flowing medium from the inlet side (lower side) inflow, from the outlet side (upper side) outflow. When the inlet pressure is greater than the weight of the valve flap and the sum of its resistance to flow, the valve is open. Conversely, the valve is closed when the medium flows backwards.
2, check valve can prevent the pump and drive motor reversal:
Check valve is automatic, in a direction of flow under the action of fluid pressure, the valve is open; fluid flow in the opposite direction, by the pressure of the fluid and the valve flap of the weight of the valve flap action on the valve seat, thus cutting off the flow.
3, check valves can also be used to give the pressure of which may rise to more than the system pressure of the auxiliary system to provide supply pipeline. Check valve can be mainly divided into rotary check valve (rotating according to the center of gravity) and lift check valve (moving along the axis). They are both used in one-way flow of media on the pipeline, only allow the medium to flow in one direction to prevent accidents.
Classification of check valves
By structure, it can be divided into three kinds of lift check valves, swing check valves and butterfly check valves:
1. Lift check valves are divided into two kinds: vertical and horizontal.
2, swing check valve is divided into single-valve, double-valve and multi-valve type three.
3, butterfly check valve is straight-through type.
The above types of check valves in the form of connection can be divided into threaded connection, flange connection, welded connection and clamped connection.
The above content reference? Baidu Encyclopedia-Check Valve