Patent GB-766288-A (GB)
Title: Filtering cartridge for liquids and gases and methods for executing same
IPC: B01D29/11
Filed: 1954-11-10
Abstract: 766,288. Filters. GEWISS, L. V. Nov. 10, 1954 [Nov. 28, 1953], No. 32593/54. Class 46. [Also in Group XXVIII] A strip of paper or fabric 1, Fig. 1, of breadth equal to the difference between the outer diameter of the intended cartridge and the diameter of the axial space and of length equal to that of the cartridge perimeter, is folded lengthwise and pleated, the breadth of the pleats being a submultiple of the length of the strip. The strip is then bent in its own plane with the open edges (now lying flat) on the outside and the folded edge, chevron-pleated, at the centre. The ends of the strip are then glued together. A number of identical elements are stacked, with pleats nesting, and adjacent free edges of adjacent elements are glued together. Flat circular covers of cardboard or metal are then secured over the unglued free edges of the lowermost and uppermost elements of the completed stack, one cover at least being provided with a central opening. Spaces 3, Fig. 4, between adjacent pleats enable filtrate to flow into the axial space. Instead of glue, axial pressure may be sufficient to seal the elements together, in which case the two edges of each element are kept apart by cardboard or paper shims cut at intervals to provide a passage for the liquid. The strip 1 may be coiled with its open edge inward. In Fig. 5 a strip of indefinite length is folded lengthwise, pleated, and helically coiled edgewise with the free edges outward. The strip is compressed during winding and adhesive or staples 6 are applied to secure in a continuous manner the lower free edge of any convolution to the upper free edge of the convolution below it. As before, the free edges may be on the inside instead of the outside of the completed cartridge. In Fig. 7, the strip after folding and pleating is wound upon itself so as to provide the first convolution with a number of pleats corresponding to the length of the perimeter of the cartridge and the free outer edge of each convolution is then glued to the free inner edge of the following convolution, the pleats being nested. Before the central turns are compressed to a tooconsiderable extent the winding is stopped. One axial end of the coil is then urged towards the axis, the other end thus expanding to form the periphery of the now disc-shaped element. A unit is thereafter obtained by superposing, a number of such elements endwise and securing them between covers. To produce the unit of Fig. 8 a sheet is first folded along a number of parallel lines parallel to the intended axis of the unit, to produce zig-zag pleats each having a breadth equal to the intended radial thickness (approximately) of the unit. The sheet is then further folded along lines perpendicular to the first ones to produce small transverse pleats 8. The pleated sheet is then shaped into hollow tubular form and the two terminal edges glued together lengthwise of the unit, the adjacent pleats nesting. Covers 9 and 10 then complete the cartridge as shown in Fig. 8. It is then compressed axially. In Fig. 5 the original strip may be folded longitudinally to provide four, six or more layers instead of the two shown. A perforated tube may be provided, in all cases, either inside the axial opening or over the outer periphery of the cartridge.