GB811129A - Improvements in or relating to devices for measuring the liquid contents of containers - Google Patents

Abstract

811,129. Magnetic couplings. FLIGHT REFUELLING Ltd., and JONES, E. C. March 28, 1957 [April 24, 1956], No. 12553/56. Class 35. [Also in Group XVIII] In a device for measuring the level of liquid in a container 10 an annular float 47 is mounted slidably on a non-ferrous metal tube 15 projecting vertically upwards within the container and an annular permanent magnet 49 carried by the float forms one member of a magnetic coupling having diametrically opposed N and S poles; the other member 22 of the magnetic coupling is carried by a slider 19 to which is attached a tubular measuring rod 29, the slider being slidably disposed within the tube 15. When not in use, the measuring rod 29, together with the slider 19, is pushed up into the tube 15 (see Fig. 4) and held in this position by means of a spring 43 which engages a groove 46 in a disc 32 carried by the measuring rod 29. The end 44 of the spring 43 is bent down and formed into a handle and, when the spring 43 is pulled clear of the groove 46, the rod 29, together with the slider 19, is free to fall until the magnetic coupling member 22 reaches a position within the other member 49 of the magnetic coupling, the level of liquid being indicated by markings 55 on the rod 29. The tube 15 is fitted within a hollow boss 13 of a disc 12 which is bolted to the container 10, the interior of the tube being sealed from the inside of the container by means of a cap 17 and packing rings 16, 18. Mounted in the lower part of the tube 15 around the measuring rod 29 is a cylindrical shell 35 provided with washers 38, 39 respectively engaging the tube and the rod, the shell being urged downwardly by a tapered-coil spring 41 which is compressed when the rod is held by the spring 43 in the unused position. The float 47 and the slider 19 are provided respectively with ball bearings 52, 52 and 26, 26, and a very small clearance is provided between the magnetic coupling member 22 and the tube 15 so that, when the measuring rod 29 and the slider are free to fall, the resistance caused by this small clearance to the passage of air from one side of the slider to the other controls the rate of downward movement. In modifications, the tube may extend into the container from the container upper wall, or the measuring rod may be mounted externally of the container against a side wall thereof.