Patent GB-532380-A (GB)
Title: Improvements in liquid level indicators
IPC: G01F23/42
Filed: 1939-04-21
Abstract: 532,380. Indicating liquid levels. LANG, C. A. April 21, 1939, No. 12033. Convention date, April 25, 1938. [Class 123 (i)] [Also in Group XIX] In apparatus for indicating small changes of level, e.g. in oil storage reservoirs, a heavy body 15 which remains on the liquid surface, is suspended by a wire 13 passing over pulleys and through conduits 6, 2 to an indicator 10. A counterweight 17 is provided with a loop chain 18 attached to a fixed point 21 which compensates for the variable weight of the wire 13 as the body 15 moves. The indicator casing is provided with a glass window covering a sectorshaped opening 48 through which part of the dial 12 is visible. The mechanism is supported by a rectangular frame 53, 54, 55, 56 resting on lugs 51, and comprises a drum 60 over which the wire 13 is wound, and a spindle 65 over which the counterweight wire 64 passes. The drum is supported in ball bearings and the shaft passes through the front cross bar 54 and carries a pinion 71 gearing with a rack 72 within a frame 74 with pointer 82 and a flag 83 which hangs vertically. The dial 12 is provided with a spiral marking 85 which is the line defined by the pointer 82 as the liquid level changes. A circle 86 carries fractional indicia adjacent to a fixed pointer 87. The flag 83 gives a general indication of liquid level, and the pointers 82, 87 give accurate readings in units and tenths of a unit respectively. The body 15 may be boat-shaped, Fig. 6, and of metal of a specific gravity greater than the liquid. The body 15 is pivoted at 9 to the wire 13 and is formed with a keel 8 to minimize resistance to liquid movement, so that guides within the tank are unnecessary. In a modification, Fig. 7, not shown, the variable weight of the wire 13 is compensated by suspending the counterweight 17 by a wire passing over a conical spindle, Fig. 7, not shown, or by a tape winding upon itself, Fig. 8, not shown. If the weight of the wire 13 is negligible, the compensating arrangements may be omitted. Part of the counter-weight may be placed at 17<SP>1</SP>, Fig. 1, so that the bearings of the indicating mechanism are not overloaded. The Specification as open to inspection under Sect. 91 describes modifications of the indicating mechanism. In a modification, Fig. 5 (Cancelled), adapted for liquids under pressure, or corrosive or volatile liquids, the drum 60 and indicating dial 12 are in separate compartments 92, 91, separated by a non-magnetic shell 102 which houses a magnet 107 carrying soft iron pole pieces 108 provided with teeth, Fig. 8 (Cancelled). The dial shaft 110 is mounted in ball bearings and carries a similar flag and pointer mechanism 73 to that of Fig. 3. A magnet 115 with toothed pole pieces 116 is mounted between flanges 114 carried by the shaft 110. Another modification, Figs. 9 (Cancelled), and 10 (Cancelled), not shown, employs a telemetric transmission in which the angular movements of a magnet such as 115 are transmitted electrically by known means to a distant receiver having a dial and pointers similar to those of Fig. 3. A modification is described, Figs. 12 (Cancelled) and 13 (Cancelled), not shown, which is applicable to underground tanks and in which the indicating dial is horizontal. This subject-matter does not appear in the Specification as accepted.