A
wafer butterfly check valve has the valve clack opened and closed automatically by the fluid of media for preventing backflow of media, which is also known as a backflow
valve, non-return
valve, reflux
valve and pressure relief
valve. With simple structures, this kind of
valve can only be mounted on the horizontal pipe.
The
wafer butterfly check valve is one kind of
check valves, ideal for industrial pipes to prevent backflow of media. The valve is divided into three categories according to the operation mode of the valve clack: swing check valves (rotating around their centers of gravity), lift check valves (moving along with the axis),
butterfly check valves (rotating around the valve's center).
A check valve can run automatically to prevent the backflow of media, the inversion of pumps, the inversion of drive motors as well as the leak of media within the container. Moreover, the check valve is also used for the pipeline which may have an internal pressure higher than the pressure of the auxiliary pipeline.
The
butterfly check valve regulates the fluid by making media flow in one direction. In general, the valve runs automatically and the valve clack is opened under the pressure's effects of the fluid flowing in one direction. In the opposite direction, the effects of the valve clack act on the seat due to the fluid pressure and the weight of the valve clack so as to block the flowing fluid.
Since the
butterfly check valve has the similar shape of the valve body to the globe valve's, the
butterfly check valve has big flow resistance coefficient. Valve structures of the
butterfly check valve and globe valve are also similar and their valve body are the same.
The top of the valve clack and the bottom of the valve bonnet have the pilot sleeve, and the pilot sleeve of the valve clack moves up and down freely inside that of the valve bonnet. When media flow downstream, the valve clack is forced to open by the media. When media stop flowing, the valve clack drops to the valve seat by its weight, which cuts off the media flowing back.
The discoid valve clack of the
butterfly check valve rotates around the shaft inside the passageway of the valve seat. The streamlined passageway inside the
butterfly check valve makes the butterfly check valve suitable for working conditions with the large caliber, low velocity and steady flow instead of working conditions with the pulsating flow due to its worse sealing performance compared with the lift check valve's.
According to calibers of valve, the
butterfly check valve is divided into three categories: the flap check valve, the double-flap check valve and the multi-flap check valve. The flap's design is ideal for reducing the impact of the water power when the valve media flows back or stop flowing.
