GB150349A - Method and apparatus for indicating level of liquids - Google Patents

Abstract

150,349. Merrick, A. A. Aug. 25, 1919, [Concention date]. Draught, indicating.-Liquid-levels are measured by establishing during each individual indicating operation a column of the liquid which is connected to a normally balanced gauge column, the first mentioned column being brought to a pre-determined height by changing the pressure in the connexion between the columns. Primary applications are the sounding of a ship's ballast tanks, and the measurement of a ship's draught. In the general form, shown in Fig. 4, a U-tube mercury gauge 12 fitted with a scale graduated on one side for oil and on the other for water, is connected at the inner limb by a pipe 13 to the top o! a second column member 11, fitted at the bottom with a valve 10 and a pipe 9 common to pipe leads from the ballast tanks, each lead being fitted with a valve 6. The pipe 13 is connected to a vacuum producer or condenser 15 by a pipe 14 having a needle valve 19 and an air valve 21. To measure the level in a tank below the indicator the particular valves 6, 10 and 19 are opened until the liquid rises in column 11 to a mark 0, 0, when the valve 19 is closed. The level in the tank is indicated by the difference of levels in the U-tube. To measure the level in a tank above the indicator, the valves 6, 10 and 21 are opened until the pressure of the air compressed in pipe 13 is reduced sufficiently to allow the liquid in column 11 to rise to the level 0, 0, when valve 21 is closed. By fitting a column 11 to the pipe from each tank, and connecting the tops of these columns by a common pipe 13, the soundings of a. plurality of tanks may be taken at the same time,. the tubes 11 also being calibrated. In another method, the tube 11 is calibrated, and a sufficient vacuum produced in the pipe 13 to draw all the mercury into the inner leg. The mercury gauge may be replaced by a pressure and vacuum gauge, correction being made in this case for atmospheric pressure. To adapt the gauge for measuring the draught of a ship, the pipe 9 is fitted with a sea-connexion at a known vertical distance below the indicator. In every case the vertical distance from the indicator to the bottom of the tank must be known. A correction is applied in the case of a ship with a list by measuring the angle of inclination by a clinometer, &c. The effects of rolling and pitching are obviated by making the pipe 9 of small bore and by throttling the supply to the indicator through the valve 10.