GB907485A - Apparatus for reducing the liquid content of liquid-containing fine-grained solid material, such as coal slurry - Google Patents

Abstract

907,485. Presses for separating liquids from solids. STAMICARBON N.V. Dec. 14, 1960 [Dec. 18, 1959; May 14, 1960], No. 43116/60. Class 46. The pressure chamber is located between an elastic membrane and a pervious wall; the other side of the membrane forms, with an impervious wall, another chamber which can be evacuated prior to introduction of charge to the pressure chamber, and subsequently be filled with fluid to force the membrane against the charge for the compressing phase. In Fig. 1 the pressure chamber 2a is located between a central cylindrical pervious structure 7, 10 and a membrane 2, and the other (operating) chamber, 3a, between the membrane 2 and an outer impervious cylinder 16. First, chamber 3a is connected to a pump cistern 31 placed about 10 metres below the main apparatus so that when water already present in chamber 3a has run back into the cistern a vacuum is created in the chamber, drawing membrane 2 against cylinder 16 (see right-hand side of Fig. 1). Valve 28 is then opened to admit e.g. coal slurry from a stirrer tank 29 through a set of open valves 15 to the pressure chamber 2a. In the next (compression) phase liquid is conveyed to chamber 3a, first by a low pressure pump 34 and later by a high pressure pump 35. Filtrate is expelled through a pipe 12. Next, valve 38 is closed and valve 39 is re-opened to re-create vacuum in chamber 3a. A piston 44 is next raised by compressed air so as to lower the central filter assembly 7, 8, 10, 20 a short distance. Then compressed air is admitted to a tank 23 and thence directly to a cylinder 53 to close filtrate valve 13. Thereafter a valve 22 is opened suddenly to discharge the compressed air into cylinder 7 to dislodge the filter cake, which drops to the exterior between a lower end member 8 on the filter cylinder 7 and a lower cover 5 on the outer cylinder 16. The apparatus is then reset for the next cycle. In Fig. 3 (not shown) the filter assembly is fixed and the apparatus has a lower hinged door to close the pressure chamber. In Fig. 7 the membrane 2 is located between a central triangular member 74, providing three separate operating chambers 3a, and an outer cylindrical filter assembly 10, 7. In Fig. 5 (not shown) the locations of the chambers are reversed as compared with Fig. 7. In Fig. 9 a central triangular filter assembly 74 is surrounded by a cylinder 16. In contradistinction to Fig. 1, the valves 15 are provided in association with the fixed part of the apparatus, namely in an extension 87 incorporating a feed chamber 88. The end members 78 on the filter assembly are hollow, and the lower one provides communication between the underside of filter gauze 10 (via grooves and ridges 9) and the interior of member 7 (via openings 84). Before slurry can be admitted to the pressure chamber the filter assembly must be raised to the dotted line position. In Fig. 6, (not shown), the openings 84 are omitted, and a filtrate pipe is connected to the interior of the lower end member 78. In Fig. 11 the inlet valves 15 are provided on the central filter assembly, which must be lowered before charging can take place. The end clamping rings 5 on the outer fixed assembly are provided with scraper edges 72 for removing the cake during relative axial movement. Fig. 12 (not shown) combines certain features of embodiments previously described and has a recessed outer filter member.