GB1260132A - Improvements in apparatus for indicating liquid level - Google Patents

Abstract

1,260,132. Valves. G.K.N. SCREWS & FASTENERS Ltd. 24 June, 1969 [3 May, 1968; 19 July, 1968], Nos. 21001/68 and 34448/68. Heading F2V. [Also in Divisions G1 and H1] A device for indicating the level of oil in the oil sump of a motor vehicle engine comprises a float 21 movable in a chamber 10 connected via a conduit 14 with the inlet manifold, the float closing a valve arrangement when the oil is at the desired level 27 such that a vacuum is created above the float 21 so that it is suddenly urged upwardly causing its end 26 to actuate an electric switch, by separating contact spring blades 15 thereof, in an indicating circuit. Float 21 has a projection 22 of cylindrical stepped configuration, the portion 24 being a clearance fit in a passage 12 whilst the portion 23 sealingly engages the passage to provide closure of the valve arrangement when the oil is at the desired level. With oil below level 27, the portion 23 never reaches such sealing engagement. Inclined portion 28 moves into fluid-tight engagement with a countersunk part of passage 12, when the float is moved fully upwardly, to prevent oil passing through the passage into extension chamber 13. Chamber 10 communicates with the oil via a large diameter passage 19, Fig. 1, or by a conduit 34, Fig. 6, adapted to be inserted through the normal dipstick aperture in the vehicle engine cylinder block. To prevent unwanted operation of the sensing device during acceleration, an expansion chamber 29, Fig. 4 (not shown), is provided in conduit 14 and includes a ball valve 32 with a small bleed controlling fluid flow. Oil level is sensed only when the engine is started in the Fig. 6 embodiment. A further embodiment, preventing splashing oil from operating the sensing device, includes a time delay valve 35 at the bottom of chamber 10. With oil at the normal level 27, the delay valve piston 37 does not move appreciably to close passages 39, 41, because its movement is retarded by the restricted rate at which atmospheric air passes through the bleed aperture 40 into the cylinder 36, and accordingly oil is drawn up conduit 34 as in Fig. 6. With oil below the level of conduit 34 however, no oil rises up the conduit 34 to move float 21, but the suction in chamber 10 causes spring-loaded piston 37 to close the apertures 39, 41. This movement is retarded by bleed passage 40 and a dashpot (not shown). The indicating circuit gives a visible or audible warning on opening or closing of contact blades 15.