Butterfly non-return valves
Of the flanged non-return valves, the models fitted with flaps are the simplest in terms of their operation. The closing flap is supported by an axle on one side, and the valve is installed with the axle upwards. Gravitational force holds the flap in the closed position, but it will open when the flow from the correct flow direction reaches the valve. The flow from the opposite side will not open the non-return valve.
The closed position of the GESTRA CB butterfly non-return valves has been secured with a special closing spring. The structure of these valves is very robust.
Relatively low flow resistance
The butterfly non-return valve is a typical non-return valve for water systems. In size classes greater than DN 100, the flow resistance is clearly lower than in the case of the RK model. However, if a small flow resistance is a selection criterion, the resistance is clearly higher in butterfly non-return valves than in dual-butterfly non-return valves.