Patent GB-640151-A (GB)
Title: Improvements relating to liquid or oil filtration systems
IPC: B01D35/14
Filed: 1946-11-11
Abstract: 640,151. Lubricating. TECALEMIT, Ltd., and LE CLAIR, C. C. S. Nov. 11, 1946, No. 33527. [Class 12 (iii)] [Also in Group I] An oil filter includes a control valve member provided with a deformable member, for example a diaphragm, capsule or bellows, by means of which the valve is unseated and unfiltered oil is allowed to return to the sump through a subsidiary outlet when the pressure of the filtered oil in the main outlet passage exceeds a predetermined value. In the embodiment shown in Figs. 3 and 4 the valve mechanism is enclosed in a casing 4 within a filter head 1 provided with a filtered oil inlet 3a, an unfiltered oil inlet 2a, and a subsidiary outlet 10, all of which register with corresponding apertures in the wall of the engine or the like to which the filter is attached. A valve head 35, Fig. 4, co-operating with a valve seat member 20 is fitted to a valve spindle 34 in part guided by a felt plug 54 which serves also to filter the oil passing through it to the interior of a bellows 40. The open end of the bellows is attached to an extension 39 of the valve seat member, and the closed end to a flange 41 on the valve spindle 34. The other end of the spindle 34 is housed in a piston member 44 sliding in a closure plug 25 and having a shouldered flange 43 engaged by a spring 42. The whole of the region round the bellows 40 and a space 46a in the closure plug 25 are filled with filtered oil, which has access through ports 11, annular groove 52, ports 53, and groove 47. In operation, the pressure of the filtered oil acting on the bellows 40 against the action of the spring 42 causes the valve member to move to the left and the head 35 to leave its seating on the member 20a permitting unfiltered oil to flow through the bore 13 to the subsidiary outlet 10 when that pressure exceeds the predetermined value, as shown in Fig. 4. In the embodiment shown in Fig. 5, the filtered oil pressure communicates through a closure-member 25a and ferrule 56 with the inside of a bellows 40a, unfiltered oil being admitted to the space surrounding the bellows through ports 65. The bellows 40a has its open end attached to the ferrule 56, and its closed end to a flange 58 on a valve spindle 34a, a valve head 35a being guided by a flexible diaphragm member 35b sliding or flexing in the bore 13. A spring 42a at its movable end presses against a flange 62 on a hollow sleeve member 61 attached to the flange 58. In a modification (not shown), of the construction of Fig. 5, the ferrule 56 extends into the bellows 40a, and a hollow extension of the valve spindle slides within the ferrule, the filtered oil reaching the inside of the bellows through cross-ports in the spindle extension. Where the bellows 40a of the device in Fig. 5 is sufficiently rigid laterally, the valve head 35a may be of frusto-conical form, closing on the valve seating member 20b with a self-centring action, the guide member 35b being dispensed with. In the construction shown in Fig. 8 a casing 70 is in the form of a pressing attached to a flange 83 of a closure member 84, which also houses a control spring 118 between a shoulder 119 and a neck-piece 123 held on a spindle 97 by a spring 120. The open end of a bellows 107 is attached in a counterbore 92 of the closuremember 84, and its closed end to a flange 101 on the valve spindle 97. The assembly is guided by diaphragm members 114 and 102, a frustoconical valve head 98 making dirt-cutting engagement with the edge of the aperture 106. Filtered oil reaches the interior of the closuremember 84 and a closure cap 111 through a port 80, duct 78, ports 97, annular groove 95 and ports 96, and the interior of the bellows through a bore 91. Unfiltered oil reaches the remainder of the casing through inlet 79, duct 77, and ports 77a. In modifications of this arrangement (not shown), the bellows are replaced by a flexible diaphragm, and by a flexible capsule, respectively. Specifications 556,304 and 621,053 are referred to. The Provisional Specification also refers to Specification 640,150.