GB959042A - Filter coils and methods of making them - Google Patents

Abstract

959,042. Filtering fluids. MINE SAFETY APPLIANCES CO. Aug. 1, 1961, No. 27957/61. Headings B1D and BIT. A filter coil comprises a single strip of filtering material and a pair of corrugated separator strips, the strip of filtering material having been folded about at least one separator strip and the strips having been rolled into a coil with adjacent edges of the strip of filtering material sealed together so that in radial cross-section the strip of filtering material forms a continuous zig-zag, with the adjacent lengths of the filtering material constituting the zig-zag spaced by one or other of the separator strips. As described with reference to Figs. 3 and 6 a strip 2 of filtering material extends laterally from between adjacent faces of two corrugated separator strips 1, 3 partly around the latter which may be made of metal or paperboard, the strips in combination being rolled into a coil around a core member 4 and the overlapping edges of the strip 2 preferably being sealed together by adhesive 5. The coil is held together by an impervious band 6 and may be cylindrical, elliptical, triangular, or square. In a second embodiment, Figs. 8 and 10, a strip 12 of filtering material extends laterally around a corrugated separator strip 11, both edges of the strip 12 projecting from one edge of the strip 11; a second separator strip 13 is added and the strips are then rolled into a coil and the marginal portions of the strip 12 at opposite sides of the strip 13 are sealed together at 15. U.S.A. Specification 2,889,932 is referred to.