Patent GB-952235-A (GB)
Title: Improvements in or relating to filter presses and methods for separating solids from liquids
IPC: B01D25/00
Filed: 1961-12-07
Abstract: 952,235. Filter presses ; presses for separating liquids from solids. ALMASFUZITOI TIMFOLDGYAR. Dec. 7, 1961 [Dec. 12, 1960], No. 43890/61. Heading B1D. In a filter press, consisting of hollow filter frames and filter plates (the latter being intended to carry filter cloths) and wherein any two neighbouring plates and an intermediate filter frame define between them a filter chamber, a hollow resilient chamber is provided in the filter chamber and occupies at least the major portion of the volume of the latter; the material to be filtered enters the filter chamber between the filter cloths and the resilient chamber (thereby diminishing its volume) and forming a filter cake ; on opening the press the resilient chamber returns to its original volume to expel the filter cake. Positive pressure may be applied in the resilient chamber to express liquid from the cake or to expel the cake, or both. Each frame, e.g. 37, Figs. 3, 5 and 10 ; 37 and 39, Fig. 3, incorporates two elastic partitions 48, 49, in the positions shown in Fig. 3 prior to admission of pre-filt. On admission of pre-filt to cake chambers 41, 42 the size of the "resilient" chamber 46 is reduced. Next, fluid pressure greater than the pre-filt pressure is applied at 54 to the "resilient" chamber 46, to compress the cakes, and is then discontinued. Next the press members in the relevant group are separated, the cakes being left adhering to the partitions 48, 49. Finally, the "resilient" chamber 46 is slightly pressurised to cause bulging and consequent cake removal, Fig. 10. Filter plates 36, 38 have a cloth at each side. Alternatively, each filter plate may have around it an endless filter belt 94, Fig. 13, the cakes 88, 89 being left thereon and finally removed by traversing the belt by a handle at the top. The partitions 48, 49 may be replaced by a closed bag providing a "resilient" chamber of approximately the same dimensions as before, and incorporating a reinforcing frame. Alternatively, the bag may be flush with the frame surface, at least over most of its area. In Fig. 19 such a (circular) bag in a (circular) frame has a tapered portion 100a at the top to permit unobstructed entry of pre-filt at 107, 108. Where press members of the kind shown in Figs. 3, 5 and 10 are provided, the pressure applied in chamber 46 may be such that the cakes adhere to the filter cloths (somewhat as in Fig. 13) rather than to the elastic partitions. In all cases, chamber 46 may be entirely closed. Press-opening mechanism The filter press member on the extreme left of each of the groups above-mentioned has its supporting lugs (on each side of the press) extended upwards above the remainder (80, Fig. 5). A reciprocatable bar 70 having four protuberances (72 &c.) spaced along it, and projecting mutually at right angles, is provided at each side of the press. The bar also has a "control cylinder" 81 with grooves 83. The bar is moved hydraulically to the right, being rotated through 45 degrees by engagement of cylinder 81 with a pin 84 near the end of its stroke. It is rotated in the same sense a further 45 degrees near the beginning of its return stroke, the final result being separation of the members of the group as shown in Fig. 5. The three remaining groups of members are successively manipulated in the same way.