| 摘要 |
796,942. Travelling band filters. EIMCO CORPORATION. July 13, 1956 [Aug. 11, 1955], No. 21695/56. Class 46. A filtration apparatus of the pressure or vacuum type comprises an endless web filter 22 extending over a filter medium supporting device 10, a discharge roller 24, a wash roller 26 and a web-centering roller 28. The roller 28 is supported by pivotal means so that its axis of rotation is angularly displaceable. A device 50, comprising two photo-electric cells, senses deviations of the filtering medium from its central position on the support 10 and controls a servo-valve 72 in response to these deviations which causes movement of a piston rod 44 to displace the roller 28 which restores the filter medium to its central position on the support 10. In modifications the photo-electric cells may be replaced by a fluid pressure sensitive device comprising a tube, having a plurality of openings, connected to a source of vacuum. As the filter web deviates from its central position it closes or opens holes in the tube which feeds a signal to the servo-mechanism as above. The web centering roller may be mounted in universal bearings on a fixed support at one end and to the piston rod at the other. |
