Patent GB-674377-A (GB)
Title: Filtering apparatus with trays adapted to be tipped about a horizontal axis
IPC: B01D33/19
Filed: 1950-03-21
Abstract: 674,377. Filters. NAAMLOOZE VENNOOTSCHAP DE BATAAFSCHE PETROLEUM MAATSCHAPPIJ. March 21, 1950 [March 21, 1949], No. 7042/50. Class 46 [Also in Groups- XXVIII and XXIX] A filter particularly intended for separating paraffin wax from a lubricating oil to which a diluent has been added comprises a number of trays 2, Figs. 1 and 2, each capable of being tipped about a horizontal axis 3, 4, but otherwise remaining stationary, and each having an open upper part and a closed lower part separated by a filtering medium 5. The lower part of each tray 2 is connected by a hollow pivot 4 with one of the sectors of a stationary valve box 8, Fig. 4, the bottom of which is provided with four series of part-annular openings, 9 to 9<SP>111</SP>, which are situated at different distances from the vertical axis of the apparatus and can be closed and opened by a disc-shaped valve plate 10. Opposite the openings 9<SP>1</SP> to 9<SP>111</SP> are annular openings 11 to 11<SP>111</SP> in a casing 12, which give access to annular spaces in the casing, each of which is connected with a separate pipe 13, of which only one is shown in Fig. 1. The valve plate 10 is rotated by a shaft 14 which carries at its upper end a tray having five annular open channels 17 to 21 Figs. 1 and 2, channel 17 being fed by a pipe 22 with liquid to be filtered and the remainder by pipes 23 to 2E with washing liquid. A radial channel 27 conveys liquid tc be filtered from channel 17 to discharge channels 28. A radial pipe 29 leads from each of the other channels to a pipe 30 with nozzles for discharg ing the washing fluid. Four series of holes 31 to 31<SP>111</SP> are provided in the valve plate 10, Fig. 5, to permit communication between each of the trays 2 and each of the four pipes 13 in turn during one revolution. In operation, with the valve plate in the position of Fig. 5 and the distributing apparatus in the position of Fig.. 2, tray A is empty and ready for re-charging, tray B is being tipped and supplied with compressed air for removal of thecake from an appropriate pipe 13 through port 31, C is undergoing the fourth and lastwashing-out, D and E the third, F, G and H the second and J, K and L the first washing-out, the washing liquid being conducted to two pipes 13 under vacuum. In trays M to Q the oil is draining from the filter-cake. The tipping of each tray in turn is performed by a pneumatic or hydraulic apparatus operating in synchrony with the valve and distributing means. A chain wheel 37, Fig. 6, over which runs a chain 38 connected between a fixed point 41 and a weight 39, is mounted on the end of each filter tray pivot 3, which projects outside the housing 1, Fig. 1. A cam disc 54 rotated by, or synchonously with, the shaft 14 opens and closes a series of valves 45, Fig. 6, (one for each tray). While a valve 45 is open compressed air :is admitted from a pipe 47 by a camoperated valve 48 to a circular conduit 46 and thence by valve 45 to cylinder 43. A piston 42 is thus forced down to tip the tray by the chain and wheel machanism. While the valve 45 is still open the valve 48 closes and a second cam-operated valve 50 opens to permit the air in the conduit 46 to discharge through a pipe 49, whereupon the weight 39 restores the tray 2 and piston 42 to their former positions, the valve 50 then closing. Finally the valve 45 closes. The filter cake discharged on to the floor 32, Fig. 1, is conveyed by scrapers 35 to a radial trough 33 in which is arranged a conveyer screw 34. The :scrapers may be driven by a separate motor 36 which need not be in synchrony with the shaft 14.