GB191129301A - Improvements in or relating to Filtering Apparatus. - Google Patents

Abstract

29,301. Deacon, M., and Gore, W. Dec. 29. Filters; filters, cleansing, filtering - media, charging and discharging.-Filters of the kind described in Specification 14,487/10, in which finely-divided filtering-material is continuously removed from the bottom of the filter and supplied again at the top during the operation of the filter, are arranged so that liquid to be filtered is admitted to the filtering-material at the side as well as at the top and filters inward to a central collector, advantage being taken of filtering-films which form around a practically stationary central cone of the filtering-material. Fig. 1 shows a filter adapted for use below the ground-level. Inside the concrete pit A, the filtering-material is confined within a liner B, which is perforated or built up of short cylinders or rings arranged to leave spaces for the entry of the liquid. At the bottom is a hopper-shaped liner E with a top E<1>. The small pipes J, J<1> pass down to the bottom of the pit through a central tube H which is itself surrounded by a perforated tube F. The lower ends of the pipes J, J' are arranged to form an ejector. Water from the main M passing down the pipe J draws sand continuously up the pipe J' to a washer L from which the clean sand is delivered to the top of the filter by the water in the main. The sand falls to the space beneath the liner E through slots P or through the space between the bottom of the liner B and the hner E. The medium within the broken line O is practically stationary, and one or more filtering- films will be formed in this position in addition to the horizontal films formed in the rest of the medium. The liquid filters across to the tube F and is discharged through the main M<2>. The filter shown in Fig. 3 is adapted for use above the ground-level. The hopper E is not closed in but it is partially filled with concrete. There is an outlet at the bottom of the central cone which is controlled by a valve R operated by a hand-wheel R'. The washer L is at the bottom, the washed sand being carried up the main M. Fig. 6 shows the lower part of another arrangement in which a casting S is provided beneath the conical bottom of the vessel A' and the filtered liquid passes down the central passage and through openings S' to an annular space S<2> and the main. The sand falls downwards through passages in the casting to the outlet S<4>. Instead of using a liner B, the liquid may be supplied to the filtering-material through perforated tubes placed vertically in the filtering-material near the walls of the pit or container.