Improvements in or relating to liquid level measuring and indicating devices

摘要

533,074. Indicating liquid levels. LANG, C. H. April 25, 1939, No. 15295/40. Convention date, April 25, 1938. Divided out of 532,380. [Class 123 (i)] [Also in Group XIX] A device for indicating the level of a body of liquid includes a displacement member coupled to a flexible suspension means and freely suspended therefrom in the liquid, and indicator means directly actuated by winding means for the suspension means, said indicator means including a pointer and dial with a rack and pinion mechanism for moving the pointer radially across the dial from a position near the centre to the edge of the dial. In the general layout Fig. 1, the liquid level gauge 10 is mounted adjacent an oil tank 30. A boat-shaped or otherwise formed displacement member 15 with a specific gravity greater than that of the liquid is suspended by a wire 13 which passes over idler pulleys 14 and is attached at its other end to a drum 60 Fig 2, carrying an indicator dial 12. A cable 64 attached to a drum 65 supports a counter-weight 17 provided with a loop chain 18 attached at one end to the counterweight casing 21. The weight of the chain 18 supported by the counter-weight balances that of the chain 13 between low and high level. Instead of a chain to maintain a constant torque, a fusee or a tape which winds upon itself may be employed. A counter-weight 171 may also be attached to the suspension wire 13 and the weights 17, 171 may be supported by springs. The indicating dial 12 and drum 60 are secured on a spindle 66 supported on cross bars in the casing. The spindle 66 is formed with a pinion 71 which co-operates with a rack 72 Fig. 3 carried in a frame 74 ... 76 slidable in grooves in a block 80 attached to the front cross bar. The top of the frame carries a pointer 82 and a screen 83 to co-operate with the spirally arranged graduations 85 on the dial. The movement of the rack bar is limited by providing upper and lower blank spaces 84 in the rack. A fractional scale 86 on the periphery of the dial co-operates with a fixed pointer 87. In instances where the liquid is maintained under pressure or where corrosive fumes are evolved the indicating part of the instrument is housed in a separate part of the casing, the rotation of the drum 60 being transmitted by a magnetic coupling 90, Fig. 5, to the pointer and dial 12. The shaft of the drum carries a block 107 of permanently magnetized material to which is attached soft iron pole pieces 108 with toothed edges. A cylindrical shell 102 of non-magnetic material surrounds the pole pieces and outside the shell the indicator shaft 110 carries a block of magnetic material 115 with similarly toothed pole pieces 116. In a modification the magnetic coupling type of instrument may be combined with a telemetric system to indicate on a receiving instrument at a distance or central station. A horizontally arranged indicator may be provided for use with underground tanks.