Patent GB-545990-A (GB)
Abstract: 545,990. Filters; rotary engines. AKTIEBOLAGET BOLINDER-MUNKTELL. Dec. 17, 1940, No. 17771. Convention date, Nov. 8, 1939. [Class 46] [Also in Group XXVI] An oil filter comprises a filter surface consisting of a coil of wire 29 of a diameter less than .25 mm. wound between perforated and corresponding longitudinally-grooved parts 25, 31- of a rotatable drum with the spacing between adjacent turns less than .025 mm., the chambers formed by the grooves being brought successively into communication with a chamber 40, having an internal pressure less than the oil pressure in the drum, to provide a counterflow for cleaning the wire. The diameter of the wire is preferably of the order of .1 mm. and the spacing of the turns of the order of .01 mm. In filters for combustible oil, the wire convolutions may be in direct contact with one another. The wire is preferably of stainless steel and embedded in a brass part 25. As shown in Figs. 1 and 2, oil flows from an inlet 43 through the drum to an outlet 44 and oil from the drum flows through a conduit 58 to operate a gear wheel motor 50, connected through gearing 55 with the driving spindle 24 of the drum. The chamber 40 is formed by projections 39 on a member 37, which is forced by a spring 38 into engagement with the part 31 and has an outlet 41. As shown in Figs. 6 and 9, the drum is operated intermittently by a vane 61, carried by a vane piston 60 and reciprocated in a space 65 by oil flowing from the drum through pairs of passages 87, 88 brought alternatively into register by an arm 84, which moves with the vane piston and operates a spring- controlled arm 78 to rotate a slide 66. The shaft 24 is secured to a boss 68, which is carried along by locking rollers 73 in one direction and locked by rollers 70 during the return movement of the vane. As shown in Figs. 10 and 11, the spindle 24 is secured to the piston 93, carrying the vane 94, so as to move therewith. Oil is supplied from the drum to the space 98 through a channel 99, one or other of two passages 100 in the piston 93 and one or other of two passages 101 in a slide 97, the oil in the space on the opposite side of the vane escaping through one or other of the passages 100 a passage 102 in the slide and a conduit 104 to a screw-controlled outlet 106. The piston 93 is formed on both sides of the vane 94 with opposed pairs of recesses adapted to receive diametricallyopposed spring-pressed rollers 109 guided by two discs 114, one of which carries a pin engaging an arcuate slot in the cover 63 of a length less than the angular movement of the piston and the other is formed with slots receiving pins on the slide 97. Similar relative angular movement to the latter is provided b:tween the piston and the slide. The rollers 109 move with the piston and the slide until they are stopped by the pin reaching the end of the slot in the cover 63 and, by the continued movement of the piston and slide, are then caused to snap over from one pair of notches to the other and carry along the slide thereby shutting off the oil supply to one side, and opening it to the other side of the vane. The hydraulically-acting driving mechanism may be combined with a mechanically or manually operable rotating device or the filter may be driven solely by a mechanical device.