Patent GB-829944-A (GB)
Title: Process and apparatus for desiccating moist material
IPC: B01D25/12
Filed: 1956-03-27
Abstract: 829,944. Filters; presses for separating liquids from solids. EMELE, O. March 27, 1956 [March 29, 1955; Aug. 3, 1955], No. 9514/56. Class 46. Material to be filtered and pressed, e.g. moist peat or sedimentary sludge, is introduced into a number of compartments 9, Fig. 1, each bounded by a filter cloth 12 covering a pressure plate 6 and by a flexible impermeable membrane 7 of rubber or the like secured to a frame 8 which is secured in turn to a pressure plate 5 by an elastic spacer 10 of foam rubber or the like, Fig. 1. The membranes 7 are bulged by the filling operation into contact with the pressure plates 5, as shown, and filtrate produced at this stage flows down elevations 11 on the plates 6 past deflectors 23 into troughs 24. When filling is complete the compartments 9 are reduced in width by a pressing piston 29, the solids being thereby forced into the form of Fig. 2. In the next stage, Fig. 3, the several plates 5 and 6 are separated to their fullest extent by the piston 29, whereupon the membranes 7 resume their normal shapes and the cakes part from them by reason of corrugations (not shown) on the membrane surfaces. The cakes are loosened from the filter cloths by the mechanism shown in Fig. 5. Each filter cloth 12 encircles a pressure plate 6 and a movable bar 16 above it, being held in place by pins 18. The bar 16 is suspended from a fixed bar 15 (secured at 17 to the plate 6) by springs 14, and when the cloth is distorted in its own plane (as shown) by movement of the bar 16 the cakes fall. Thereafter the assembly is returned to the position of Fig. 1 for the next filling operation. The membranes 7 may be secured to movable bars 16 in the same way as filter cloths 12. In the embodiment of Fig. 9 the piston 29 is dispensed with and shafts 4 (see Fig. 1) are rotatable through a small angle. Pressure plates 5 alternate with frames 33, all supported in axially fixed positions in grooves (not shown), in the shafts 4. Each frame 33 contains a bladder 54, pneumatically or hydraulically inflatable, which may be divided by a central plate, the bladders providing, when inflated, the necessary compression. Frames 8 bearing membranes 7 are provided as before, and these are moved axially against the spacers 10 into pressemptying position, Fig. 9, by movement of lugs on their edges, in curved guides on the shafts 4 when the latter are rotated. Each pair of pressure compartments 9, Fig. 9, is bounded by an outer filter cloth 52 extending from the foot of one frame 8, over a movable bar 38 suspended by springs 14a from extensions of the fixed bar 15, and down to the foot of the next frame 8, and by an inner filter cloth 12 spanning the frame 33 and, as before, a movable bar 16. In Fig. 13 the frames 8 are moved to " compartment-closed " position by hydraulic or pneumatic inflation of hoses 64 and are moved back upon deflation of them by springs 65 as shown. Each compartment 9 is divided into two by a filter cloth 67 secured at the bottom to a fixed bar 68 and at the top to movable clamping apparatus 69. Membranes 70 are provided on either side of the bladder frame 33 and these membranes together with the membranes 7 are also secured at the top to clamping apparatus 69.