Double flap valve is continuous material discharge equipment. Double Flap Valve has a two door flap plate which open and close alternatively.
As the material falls on the top plate, during continuous operation the plate opens and discharges the material on the bottom plate. After discharging the material the top plate closes. This ensures that the DFV is sealed to prevent air leakage.
The bottom plate then opens after the top plate is closed and allows material to fall onto onward collecting equipment.
The cycle time is precisely adjusted such that after the bottom plate closes the top plate opens. Thus ensuring continuous air sealing across the DFV. The time for which both flap are in closed condition, is known as dwell time.