Patent GB-504413-A (GB)
Title: Improvements relating to filter apparatus
IPC: B30B9/02
Filed: 1938-01-20
Abstract: 504,413. Filters. ROFFMANN, J. Jan. 20, 1938, No. 1908. [A Specification was laid open to inspection under Sect. 91 of the Acts, July 21, 1938.] [Class 46] An automatic filter in which a filter chamber is combined with a hydraulic press and preliminary filtering, hydraulic press filtering, and emptying of the residue takes place in sequence, is characterized by adjustable control means for adjusting the duration of the operations, the control means being operated by the rotation of a drive shaft. In the construction shown, a press cylinder 1 is fitted with a cover 2 surrounding which is an endless band of filtering medium 66 guided over rollers 67 ... 70. The roller 70 is adapted to be driven intermittently so that a pre-cleaned portion of the band 66 is placed between the cover 2 and cylinder 1 after each filtering operation. The cover 2 is drawn tightly against the cylinder 1 by means of claws 4 operated from a control shaft 14. This shaft carries cams by which valves are actuated for effecting in sequence the operations of the filter. The shaft 14 performs at intervals a complete revolution, this being effected by a coupling connecting it to a driving shaft 26 provided with a reversing gear 27. The shaft 26 is screw-threaded to engage a nut 29 connected to a rod 30. The rod has arms 30<1> slidably engaging a thrust rod 31 provided with adjustable abutments 32 whereby the reversing gear is operated. A ramp 34, adjustably positioned on the rod 30, is adapted, as the rod is reciprocated, to engage a roller 361 on the end of a lever 36, whereby valves 37<1>, 38<1> arc operated which control the flow of pressure . fluid to and from the cylinder 1 behind the piston 12. The ramp 34 is associated with an adjustable arm 33 which has a rack for engagement with a gear-wheel 51 whereby a hood 46 can be raised or lowered. The hood has a cam 47 which, on being raised, permits a spring- pressed bolt 44 on a drive block 43 to engage in a recess in a gear-wheel 41 loosely mounted on the shaft 14. The wheel 41 driven from the shaft 26 then drives the shaft 14 through one revolution, the cam 47 preventing further rotation. Similar means are provided for producing a complete revolution of the roller 70. In operation, liquid to be filtered is forced by a pump through line 54 into the space between the cover 2 and the piston 12. The pressure of this liquid is resisted by hydraulic pressure applied to a plunger 7 in an auxiliary cylinder 6. Preliminary filtering commences and is ended when valves 37<1>, 38<1> are operated, whereupon hydraulic press filtering takes place. As this is being completed the control shaft 14 is given one revolution, whereby the cover 2 is opened, a control 24 on the shaft 14 operates a stripper to remove press residue from the piston 12, and the roller 70 is engaged to bring a clean part of the filtering band 66 into position for the next filtration. Further movement of the shaft 14 restores the apparatus to position for commencing a fresh cycle of operations. The filtering band 66 is cleaned by means of an endless brush band 80 or a reciprocating suction nozzle 81, with or without water. swilling at 82.