Patent GB-984145-A (GB)
Title: Filter unit
IPC: B01D29/46
Filed: 1963-01-31
Abstract: 984,145. Filter units. BENDIX CORPORATION. Jan. 31, 1963 [May 14, 1962], No. 4046/63. Heading BID. A filter unit comprises a tubular housing 30 having a plurality of ports 32 (Fig. 5) therein, a porous tubular edge-type filter element 34 formed from a plurality of washers 35 in registered face-to-face contact, a movable end plate 36 and endcap 38 fixedly connected to the housing 30 and a spring 40 for placing the edge-type filter element 34 under a suitable calibrated compression. Washers 35 may be formed from paper, cellulose or other suitable fibrous or non-fibrous material and are arranged so that flow through the filter element 34 will be via the radially extending pores formed between the washers, from outside the filter element to inside. Housing 30, which may be of polyethylene, has a plurality of axially extending ribs 42 formed on its internal surface for centring and maintaining the washers in proper alignment. Nipple-like extension 44, integral with housing 30, has a bead 46 located on the outer periphery to effect a seal with the opening 48 (Fig. 1) in portion 16 of the tank 10 in which a plurality of the units 22 may be fitted, liquid, e.g. fuel, entering at 12 and filtrate leaving at 14. Endplate 36 and extension 44 are formed with conical surfaces 50, 52 which abut the ends of the filter element 34 thus ensuring that the outer edges So of the washers 35 are compressed more tightly than the inner edges Si (Fig. 4). One or more collars 54 formed with opposed conical surfaces 56, 58 are located intermediate the ends of the filter element to assist this compressing and to prevent angular misalignment of the adjacent portions of the filter element 34. In order to direct a substantially perpendicular load against the washer stack, spring 40 is centred by the recess 60 in endcap 38 and is prevented from cocking by the elongated extension 62 formed on end plate 36. Figs. 6 and 7 show an alternative embodiment. Filter unit 122 includes a metal tubular housing 130 having a number of inlet ports 132, a filter element 134 formed from a stack of washers 135, a movable end plate 136, an end closure 138 and a spring 140. Housing 130 has four axially extending ribs 142 for centring and aligning the washers and is connected to nipple-like ferrule 144, made of polyethylene which has a curved bead-like outer surface 146 for effecting a seal with the opening 148 of partition 116. Sealing is assisted by the provision of a face-type seal at 149. Throat 145 of the ferrule diverges at its outlet surface so that turbulent flow therethrough is eliminated. Collar 154 has an axial length greater than the difference between the internal and external diameters of the washers 135, to provide an adequate bearing surface and prevent the collar from cocking. Aligning collar 155, Fig. 8, may replace collar 154 if the length of the element is to be restricted. This collar has an axial length less than the difference between the internal and external diameters of the washers, but includes an annular flange 157 to provide an adequate bearing surface and prevent cocking. Fig. 9 shows a collar with concentric or spiral grooves 165 which may be used to prevent leakage. In order to direct a substantially perpendicular load against the washer stack, end plate 136 of Fig. 6 is formed so that the elongated extension 162 is located within the coil spring 140 to prevent cocking of the spring and the endplate. Fig. 10 shows an alternative endplate 137 for the same purpose which utilizes a skirt-type elongated extension 163 surrounding the coil spring. Specification 922,322 is referred to.