Patent GB-917510-A (GB)
Title: Improvements in or relating to membrane filter presses
IPC: B01D25/172
Filed: 1960-12-29
Abstract: 917,510. Filters; presses for separating liquids from solids. BORSIG A.G., and SVENSK TORVFOERAEDLING A.B. Dec. 29, 1960 [Dec. 31, 1959; Nov. 15, 1960], No. 44540/60. Class 46. Suspension which is to be both filtered and pressed is admitted under pressure at 4a, Fig. 1, to a space 4 on the right of circular elastic membrane 1a located in a membrane support 1 Filtrate passes through a filter element 2a, located in a filter support 2, into a filtrate space 5, and is discharged at 5a. Feeding is stopped at a certain limiting filter resistance A pressure medium, e.g. water, is next introduced at 3a to squeeze the filter cake by means of the membrane la, Fig. 2. Next, the pressure medium is drained at 3b, and then one or other of the supports 1, 2, is moved outwards to provide a gap 6, Fig. 3, which is wider than the cake thickness. The cake detaches itself or is detached by a pneumatic impulse in space 5 and falls through gap 6. In Fig. 4, (not shown), the supports 1, 2 are fixed and the gap 6 is bridged when necessary by an annular piston which may be reciprocated in a complementary opening in the membrance support by a pressure medium. In the remaining embodiments a number of filtering and pressing units are arranged in parallel. Fig. 7 (not shown) is a development of Fig. 4 but in which the cylindrical wall of the filter support 2 is extended beyond the end wall 49 (which remains as a partition) to form a fixed cylinder in which an open-ended membrane support is reciprocated when necessary by external piston and cylinder mechanisms. This arrangement is repeated indefinitely. In Fig. 5 (not shown) conversely, the filter supports are reciprocated in the membrane supports by pin-and-internally-grooved-ring devices. In Fig. 6 (not shown) two filter supports each similar to the right hand side of Fig. 3 and located back-to-back with filtering elements facing outwards are movable simultaneously, in a fixed cylindrical support, away from each other by pressure fluid to make contact with adjacent fixed membrane supports for the filtering and pressing stages. Each membrane frame accommodates two membranes with a single pressure space between them. The filter frames are drawn towards each other by vacuum to produce the gaps necessary for dropping the filter cakes. Fig. 9 shows a complete filter apparatus in which fixed cylindrical guides 68 alternate with fixed filter supports 62 each provided with a pair of filter elements 62a. Within each guide 68 slides a pair of inter-engaging membrane supports 61. Closure is by pressure medium admitted to spaces 90, and opening is by negative pressure in spaces 90 or by springs 70 between partitions 69. Fig. 8 (not shown) is similar to Fig. 9 but the partitions 69 are omitted. Figs. 10 and 11 show one of a number of units arranged on three rods 101 and clamped together by means (not shown). The filter support 102 is mounted in three bearing supports 109 to 111 and the membrane support 104 is movable within it. Pipes 114- 119 fixed in bearing support 111 communicate with passages 114a &c., in the unit. Each unit may be unscrewed from its bearing supports and lowered by eyelets 113.