GB1002826A - Improvements in or relating to liquid level detectors - Google Patents

Abstract

1,002,826. Liquid level control and Indication. J. FAIRHURST. May 13,1963 [May 14, 1962], No. 18389/62. Heading G1H. In a device for detection, the level of a liquid, a vertical tube 3 is secured in a container 1 containing an inflammable liquid 2 on which liquid 2 is disposed an annular float 4 supporting an annular magnet 5 which moves a cylindrical magnet 6 within the tube 3 to close an orifice 8 from an air supply line 9, when the container is full, and thus allowing the air pressure in the line 9 to build up to give an indication on gauges 11 and 12 and to operate a pneumatic relay 13 which actuates through high pressure air supply pipes 14, 15, an audible alarm or a shut-off valve. Additionally or alternatively the air pressure rise in pipe 9 deflects a diaphragm 17 connected to an electric microswitch 19. In an alternative arrangement, Fig. 2 (not shown) pipes similar to pipe 7, are provided at the top and bottom ends of the tube 3 to give a high or low level indication. In a further alternative arrangement, Figs. 3 and 3a (not shown), for providing indications at a number of intermediate levels a number of tubes terminate at different levels within the tube 3 and are closed at their exit ends by spring loaded balls which are depressed by an annular magnet within the tube 3 to allow air to escape from a particular tube and so actuate an indicator for that particular level.