GB794508A - Improvements relating to variable liquid-resistor devices - Google Patents

Abstract

794,508. Levels; gyroscopic apparatus. FERRANTI, Ltd. June 8, 1956 [March 10, 1955], No. 7005/55. Classes 97(2) and 97(3) [Also in Groups XXXVI and XXXVIII] In a transducer for tilt detection.a quantity of highly resistive liquid 15 (Fig. 2), e.g. a mixture of alcohol and lithium nitrate, is located in a glass envelope comprising a watch-glass shaped dish 11 (Fig. 3) on the uniformly concave surface of which is painted a platinum electrode having four symmetrically spaced strips 20 extending radially from a central portion 21, passing over the edge 13 of the dish 11 and continuing on the convex: surface thereof as strips 20<SP>1</SP> which combine to form a central conductive disc 22, and a watch-glass shaped lid 12 (Fig. 2) on the concave surface of which are painted four symmetrically spaced platinum electrodes 16 (two only shown) which extend over the edge 14 of the lid 12, continuing as strips 16<SP>1</SP> on the convex surface thereof..The dish 11 and the cap 12 are sealed together at their peripheral edges 13, 14, by a comparatively low-temperature sealing process, e.g. glass soldering or cementing. A coating of silver paste is baked on to the outer conductors 16<SP>1</SP>, 20<SP>1</SP>. 22, before the liquid 15 is inserted through a hole 23 (Fig. 3) between the edges 13, 14 which is subsequently sealed. A departure of the device, which may be mounted on a gyro, from the horizontal will cause an inequality in the resistances of at least two of the four paths between the liquid and the electrodes 16 which may be used to produce an error signal proportional to the slope of the device. When the detection of tilt in only one vertical plane is required the envelope may be oval or oblong with one or two electrodes 16.