| 摘要 |
A powder-conveying device (20) has a container (22) with a powder chamber (28) which is bounded by one upper and one lower porous diaphragm (40, 38). The diaphragms (38,40) are permeable to gas but not to powder. Gas under pressure is directed upwards through the lower diaphragm (38), in order to suspend powder particles of a desired size at the level of a delivery pipe (44), the inlet opening (46) of which is connected to the powder chamber (28) between the diaphragms (38,40). The gas flows through the powder chamber (28) in the form of a vortex, in order to propel particles by the action of centrifugal force towards a side wall of the powder chamber (28) at which the particles fall to the lower diaphragm (38) under the force of gravity. Powder collecting on the lower diaphragm (38) is distributed anew by a multi-vane rotor (60) which simultaneously compresses the powder. The inner end of the delivery pipe (44) penetrates into the powder chamber (28) and extends upwards. The feed of gas under pressure to the lower diaphragm (38) takes place out of a gas inlet chamber (27) which is beneath the diaphragm (38) and whose side wall (72) can be heated by heating elements (120) in order to dehumidify the gas before it reaches the powder chamber (28). <IMAGE>
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