| 摘要 |
494,854. Filters. FILTRATION & WATER SOFTENING PROPRIETARY, Ltd. July 19, 1937, No. 19958. Convention date, July 23, 1936. [Class 46] In cleaning a filter bed by upward flow of water therethrough while water is also directed under high pressure upon the sur. face of the bed, the upward flow being continued after the flow of surface wash water has been stopped, the valves are operated so as to secure a constant flow of surface wash water and a constant rate of discharge of the combined surface and upward flow wash water. The Figures show an arrangement comprising twelve filter chambers in two groups 10, 11, of six with a common supply pipe 15, a common filtrate discharge pipe 21 with valve 22 and a common wash water discharge pipe 32 with valve 33. The flow of water to be filtered to the chambers of each group is controlled by a valve arrangement as described in Specification 346,376 comprising a chamber 23 to which water from the pipe 15 passes through a branch 16 and from which it is delivered to the several chambers through ports 25 and pipes 18. When it is desired to cleanse one of the filter chambers, the valve 22 is closed and the spindle 27 of a valve member 26 is rotated manually or by an electric motor 35 through gearing so that the member 26 cuts off communication of the corresponding pipe 18 with the chamber 23 and opens it to a waste pipe 31. Filtered water from the remaining chambers then passes upward through the chamber so cut off. At the same time, jets of water are directed on to the surface of the bed from rotary distributing pipes 49 to which water is supplied through a pipe 48 from a valve device with chamber 39 and ports 40 normally closed by a valve member 41 on a spindle 37 coupled to the spindle 27. Rotation of the spindle 37 brings an aperture in the valve member 41 over the port 40 corresponding to the filter chamber which is being washed. The arrangement is such that as the spindles rotate together the filter chambers of each group are successively cleansed and that for each chamber the reverse flow of water and the flow of surface wash water start simultaneously, while the flow of surface wash water terminates before the reverse flow. The spindles 27, 37 may be coupled together in such manner as to permit adjustment of the phase relationship of the valves. The surface wash water may be under pressure of a centrifugal pump 47 and under control of a valve 45. The pipes 49 rotate on the Barker's Mill principle, and means, for example, a friction device 53, may be provided for ensuring that the rotation is such that the jets of water have a sufficiently high velocity. Each pipe 49 may be provided with two sets of nozzles 50, 51, Fig. 8. |
