| 摘要 |
A contaminated air stream from a textile operation which includes lint, short fibers, dust and other small particles is subjected to a progressive or multi-stage filter system, in which a first stage includes a rotary drum filter covered with a fine mesh screen covering which separates the lint and long fibers from the short fibers and dust which are carried on to a second stage. At the second stage filter, which is also a rotary drum filter but covered with a media type filter material, the short fibers are separated. The remaining dust and very small particles are passed on to a third stage, which is also a rotary drum filter covered with a media of even greater density than the second stage. Each of the rotary drum filters are provided with suction nozzles or other vacuum cleaning apparatus some of which are selectively moveable radially of the drum into close proximity to the surface of the filter for the purposes of periodic cleaning thereof and to a removed position in situations of non-cleaning. Others are stationary. Only one set of the nozzles are cleaning at any one particular time, which cleaning sequence is controlled by a control circuit which utilizes a differential pressure switch. The control circuit provides suction as required resulting from both movement of the first stage nozzle toward and away from the surface of the filter, and the operation of a damper downstream from all nozzles which is slowly opened and closed by the control circuit. Finally, the diametrical upstream ends of the second and third stage filters are covered with media also to provide an increased filtering area in addition to the conventional peripheral filter surfaces.
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