Patent GB-736054-A (GB)
Title: Apparatus for separating liquid from mashes and solid-liquid mixtures of similar consistency
IPC: B30B9/04
Filed: 1953-06-14
Abstract: 736,054. Presses for separating liquids from solids. FILTERPRESS AKT.-GES. June 15, 1953 [June 16, 1952], No. 16412/53. Addition to 695,605. Class 46. The spaces behind the filter plates of the apparatus of the parent Specification are permanently connected by piping for the purpose of pressure equalization. Preferably the spaces behind the filter plates are completely filled with the working-medium in any position of them. The working-medium dischargepiping of the main and auxiliary cylinders may be directly connected with a hydraulic accumulator, preferably air-loaded; the latter may be connected to the suction piping of the hydraulic pump or pumps. The mixture to be filtered is introduced at 13 into a jacket 12 and thence by slits 9 into a filter chamber 11, the filter plates 4, 5 being then in the position shown. In the preliminary filtration stage part of the liquid is withdrawn by suction from the mixture and discharged through pipes 6 to a tank 19. In the next stage a pipe 3 connecting the spaces behind plates 4, 5 is connected through a valve 38 and a non-return valve 37 to a pipe 39 fed from the intermediate pressure stage of a hydraulic pump, not shown, so that the plate 5 approaches the plate 4. During this stage valves 38<SP>1</SP> and 15 and an adjustable relief-valve 16 are closed, the righthand chamber of the auxiliary cylinder 24 and the left-hand chamber of the auxiliary cylinder 28 are connected, by three-way valves 27 and 36 respectively, to a discharge pipe 181 leading to the hydraulic accumulator 18<SP>11</SP> (delivering, at 18, to the suction side of the pump), and the right-hand chamber of the auxiliary cylinder 28 is connected by three-way valve 35 and pipe 18<SP>111</SP> with the pipe 3 so that the pressure in this chamber is the same as that behind the filter plate 4; the effective pressure on the plunger 29 added to that on the filter plate 4 ensures that the force acting on the latter is greater than that on the filter plate 5, the difference serving to hold a packing-collar 10 in place. The valve 38<SP>1</SP> is now opened admitting liquid at high pressure from the hydraulic pump through a pipe 17 to the pipe 3, the non- return valve 37 preventing escape of this liquid to the intermediate-pressure pipe 39. At the end of this stage compressed air is admitted from pipes 7 to the filter chamber 11 to remove remaining liquid adhering to the plates. Valves 38, 38<SP>1</SP> are then closed and discharge valves 15 and 16 opened, so that pressure liquid additionally pumped in during the compression stage is able to escape until equilibrium with the pressure in discharge pipe 18<SP>1</SP> is attained. The left-hand chamber of the auxiliary cylinder 28 is now connected to the high pressure pipe 17 through valve 36 while the right-hand chambers of cylinders 24 and 28 are connected by valves 27 and 35 respectively with pipes 18<SP>1</SP> and 18<SP>111</SP> respectively (the latter communicating with 18<SP>1</SP> via pipe 3 and valves 15 and 16). The plunger 29 is thus moved to the right taking with it the filter plate 4 and thus opening the press chamber 11, the plate 5 likewise being forced to the right by liquid displaced along the pipe 3, and the filter cake being forced out into a discharge device (not shown). The position shown in the Figure is finally re-attained by connecting the righthand chamber of cylinder 24 through the valve 27 with the high-pressure pipe 17 and the chambers of cylinder 28 to pipes 181 and 18<SP>111</SP> respectively through valves 36 and 35 respectively.