Improvements in or relating to liquid level devices for tilt detection

665,628. Electric indicating systems. SQUIRE, A. M., and SPERRY GYROSCOPE CO., Ltd. March 3, 1950. [Feb. 2, 1949] No. 2872/49. Class 40 (i); [Also in Groups XX and XXXVI] In a device for detecting the tilt of a platform and controlling an electrical circuit energizing a tilt indicator or a torque device for nullifying the tilt, a circular container 1 (Figs. 1, 2) contains a resistive liquid e.g. picric acid in an alcoholic solvent surmounted by a bubble 2 of e.g. air, nitrogen, or a nonconductive immiscible liquid. Four symmetrical electrodes 4, 6, 7, 8 and a central electrode 5 protrude into the liquid, and the bubble and electrodes are dimensioned so that the latter do not touch the bubble within the operational limits of the device, and the bubble deflection varies the cross sections of the paths in dependence on the degree and direction of tilt while the path lengths remain constant. The consequent resistance variations between the electrodes operate known circuitry (e.g. balanced bridges) to operate a tilt indicator or torque devices maintaining the platform vertical. The device may control the erecting torques of a gyrovertical used as a stabilising reference for the platform. In a modification, Figs. 3, 4 (not shown), the liquid and bubble are contained in a bent tube having a central electrode and symmetrical side electrodes, and sensitive to a single direction of tilt.