GB865908A - Improvements in liquid level gauges and ships' draught gauges - Google Patents

Abstract

865,908. Indicating liquid levels. DOBBIE McINNES Ltd. Aug. 12, 1957 [May 10, 1956], No. 14510/56. Class 123(1) In liquid level indicating apparatus wherein air-bells 15, 16 are respectively disposed at the bottoms of tanks 10, 11 the level in which is to be measured and a pump 14 is connected through a tank selector valve to charge one of the dip pipes and its bell with air the pressure of which is read in terms of level on a manometer gauge 12, for example of the form described in Specification 522,816, a control valve 13 is provided to allow the selected dip pipe to be placed under pressure whilst the gauge is opened to atmosphere for a zero check and the pressure source to be sealed off whilst the gauge is opened to the selected dip pipe for a level reading. Fig. 4 shows the tank selector valve 21 and control valve 20. Each consists of a casting having a through-bore, the bores being connected by ports 32. The bores contain respective piston valves 25, 22, the bore of the tank selector valve having ports 34, 35 from which connections 34A, 35A lead to respective tank air-bells whilst the control valve bore has ports 29, 30 from which connections 29A, 30A lead respectively to an air pressure source and to the reservoir R (Fig. 1) of the manometer. The pistons have waisted portions 33, the lateral ports being disposed so that movement of the piston of the tank selector valve to one of two positions connects one or other of the tanks to the ports 32. The control valve can be placed in one of three positions, a position A in which air pressure is admitted to the selected dip-pipe whilst the port 30 is open to atmosphere to allow the gauge to be checked for zero, a neutral position B with the air supply closed and the gauge connected to atmosphere and a " read " position C in which the gauge is connected to the aircharged dip pipe to indicate the liquid level. In a modification, the apparatus indicates the level in tanks operating at pressures other than atmospheric, the valve connecting the overflow cup C, Fig. 1, of the gauge to the air space in the tank in the " read " position. In a further modification the manometer gauge is replaced by a dial type pressure gauge, for example, a Bourdon tube gauge.