| 摘要 |
Apparatus for passing a feed of particulate material into a pneumatic conveyor conduit includes a charging chamber communicating with the material feed and a closure arrangement having a closure cone axially movable between a position of communicating the charging chamber with the material feed and a closure position of closing off the chamber from the feed. The closure cone is formed by the base portion of a hollow operating member extending substantially axially in the direction of flow of the material from the feed into the chamber. The operating member is generally tubular and has at least one opening outside the material flow path into the charging chamber. A closure element within the operating member is movable between first and second positions of closing and opening the opening in the operating member, in dependence on the phase of the conveying operation. When the closure element is in the position of closing the opening in the operating member, movement of the closure element also causes axial movement of the latter to displace the base portion thereof which forms the closure cone between its closed and open positions. When the closure cone is in a closed position and the closure element is in an open position, air can be vented from the chamber upwardly through the operating member and through the opening therein, around the closure element.
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