GB281817A - Improvements in apparatus for indicating or recording the level of a liquid - Google Patents

Abstract

281,817. Wollaston, H. J. Buchanan-. Oct. 12, 1926. Indicators actuated by pressure of head of liquid.-Apparatus for indicating liquid level or depth comprises a horizontal conduit which may be in the form of a coil, maintained charged with the liquid at one end, and with air at the other end which is connected to a pressure or vacuum gauge. A lamp 2, Fig. 1, is connected by a siphon 4 to one end of a pipe coil a arranged horizontally, and of such a bore that the liquid moves in it as a complete column. A pipe 5 containing air is connected to the other end of the coil a and to a similar coil b having a transparent indicating tube 3, or to an ordinary pressure gauge. The liquid fills only part of the tubes a and b. The indicator tube b may be at a distance, and if the liquid employed is the same as that in the tank, the height in the tube 3 will be the same as that of the liquid level 1 above the tube a. In a modification, the tube a may be above the tank, in which case the air pipe 5 is connected to the upper end of the tube 3, and a suction pump is employed. Any other indicating liquid may be employed in the tube 3. In another modification, Fig. 4, for indicating the draught of a ship, the horizontal pipe a is carried by a frame 10 which is supported in gimbals 11 to keep it horizontal. In another modification (Fig. 5, not shown) the liquid flows into the tube a by gravity. To avoid an inconvenient length of the tube 3, several horizontal pipes b and indicating tubes 3 may be connected in series by air pipes 5, the indications in all the tubes 3 being added together. Alternatively (Fig. 7, not shown) a constant positive or negative head may be superposed on the readings by a vertical column of liquid. Slight level variations far above or below the level of the tube a may thus be indicated on a sensitive instrument. In all the modifications, an air trap 17 may be provided to collect any air bubbles which may rise from the tube 4. Small liquid columns 'which may be formed in the tube a may pass through an extension 20, Fig. 4, into a liquid trap 21. In the application of the invention to a depth indicator (Fig. 8, not shown) the tube a is arranged above the liquid and a pipe carrying a collapsable bag is lowered into the liquid. The pipe contains liquid of a lower specific gravity, which passes through a branch of the dip pipe to the horizontal pipe coil, and its pressure is indicated as before. The apparatus may be applied to the indication of level in a petrol tank. Specification 249,653 is referred to.