Unit and method for discharging loose material from a dispensing device

A unit for discharging loose material from a dispensing device to a user unit, comprising a tube leading to the user unit, a valve element connecting the dispensing device to the tube infeed end, having an axis extending in a defined direction, the valve element comprising a first annular element, coaxial with the infeed end and comprising shutter means equipped with a first shutoff element and a second shutoff element connected to each other by releasable means and being mobile from a position in which the infeed end of the tube is closed by an airtight seal to a position where it is open, wherein the valve element comprises a second annular element coaxial with the first annular element and forming the infeed end of the tube, the first shutoff element consisting of a disc-shaped element for closing the first annular element, and the second shutoff element consisting of a screen for closing the second annular element, the valve element further comprising sealing means positioned between the first and second annular elements, separation means mobile between a first rest position where the first annular element and the related first shutoff element are respectively in contact with the second annular element and the related second shutoff element and a working position where the first and second annular elements are separated respectively from the related first and second shutoff elements in such a way as to form at least between the shutoff elements a gap that is delimited by the sealing means, and means for cleaning the gap also being provided.