Patent GB-970409-A (GB)
Title: Improvements in and relating to filters and a method for the production thereof
Inventor: BASSETT NORMAN EDGAR
IPC: B01D29/00
Filed: 1961-11-29
Abstract: 970,409. Filters. AUTOMOTIVE PRODUCTS CO. Ltd. Nov. 29, 1962 [Nov. 29, 1961], No. 42700/61. Heading BID. [Also in Division B3] A filter, Figs. 1 and 2, comprises an annular filter element 1 of wire cloth having each of its opposite ends disposed between the outer periphery 9 of an end cap 5 and an outer surrounding member 3, each end cap, adjacent annular filter portion and surrounding member being secured together by welding or other process involving heating the filter element surrounding a tubular inner member having a perforated inner wall, opposite end portions of the said inner member providing spigot portions each for location in an annular recess in the end caps, each said end cap having a rim a portion at least of which is locatable in a gap between the spigot portions of the inner member and the surrounding portions of the filter element. Fusion welding using an argon arc is preferred. The annular filter element may be pleated as shown in Fig. 2, the pleats extending radially and the element having its opposite ends formed to provide annular portions 8 of reduced section each of which is disposed between the outer periphery of the end cap 5 and the outer surrounding member 3. Such annular portions of reduced section may be formed by compressing the pleats radially outwards from inside (8, Fig. 2), radially inwards from outside (17, Fig. 4) or in both directions (27, Fig. 7). In Fig. 3 the outer surrounding member is provided by a metal ring 11 at each end of the filter, in place of the member 3. Adjacent portions of the annular filter element, end caps and outer surrounding member may be secured to one another by the same weld (6, Figs. 1, 2 and 3, and 38, Fig. 8) or alternatively adjacent portions of the annular filter element and end caps may be secured together by the same weld, the outer surrounding member being secured to the end caps by a separate weld (19, 20, Fig. 4 and 30, 31, Fig. 7). In Fig. 4, the filter comprises end caps 12, an annular pleated wire cloth filter element 13 and an outer surrounding member 14 at each end of the filter. The end caps 12 are formed integral with and at opposite ends of a sleeve 15 having apertures 16 for the passage of fluid. The outer periphery of the sleeve 15 is formed with an annular recess 39 to receive a further filter element 40 comprising a continuous wire wound round the sleeve, the wire having a tapered cross-section with a flat outer edge and provided at defined intervals with projections of uniform height arranged to space the adjacent convolutions apart, the height of the projections thus determining the degree of filtration. A similar wire wound filtering element 41 is disposed in the annular space 42 of the filter shown in Fig. 6. This filter has an annular pleated filter element 21 of wire cloth, end caps 22, an outer surrounding member 23 at each end of the filter and a perforated tubular member 24 surrounding the filter element and held in position by the members 23. End caps 22 are connected by perforated sleeve 25, to which each end cap is welded as at 26. The filter of Fig. 8 comprises an annular filter element 32 of wire cloth having a plain wall, annular portions 33 of which each end of the filter element are disposed between the outer periphery of an end cap 34 and an outer surrounding member 35 each in the form of a metal ring, the filter element being disposed around an inner tubular member 36 having a perforated wall.