| 摘要 |
The present invention relates to a device for extracting and proportioning pulverulent products comprising a hopper and coaxial screws with threads of opposite directions, driven in rotation in a cylindrical conduit, which screws are separated from each other by the wall of a tube coaxial to the screws and to the conduit, the screw of smaller diameter rotating inside the tube to convey the product therein in one direction and the screw of larger diameter rotating outside said tube to convey the product in the opposite direction, in the space defined between the tube and the conduit, said latter comprising on its periphery at least one orifice for the flow of the product, wherein said screws are composed of wires helically wound in the manner of a spring, and the tube in which the so-called extraction screw, of smaller diameter, is mounted, comprises on its periphery and on the hopper side an opening for the inlet of the product, in front of which said screws extend at least partially, which product, after having passed through said tube, is taken up by the screw of larger diameter and is transported in opposite direction and to outside the tube, on the hopper side to exert a constant pressure at inlet level, with a view to avoiding the effects of "vault" above the inlet opening and simultaneously to cause the product to pass through an orifice located on the periphery of the conduit.
|
