SEED AND APPARATUS FOR DETECTING TEMPERATURE VARIATIONS OVER OR UNDER A PREVIOUS WORLD

摘要

1526726 Detecting temperature changes SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV 13 Oct 1975 [15 Oct 1974] 44614/74 Heading G1D A temperature variation above or below a predetermined value is detected by means of a toroidal shaped element of magnetic material having a Curie Point approximating the predetermined value and two mutually inductive electrical conductors, whereby with varying current passed along one conductor the induced current in the other changes on a temperature variation. Four toroidal pieces of ferrite 20, 30, 40, 50 are each traversed by two of a network conductors 21, 25, 41, 45. A connection means (not shown) enables a varying-current to be applied selectively to the conductors and a monitoring means, e.g. a lamp, to be connected selectively to the conductors to detect induced current. As shown a cold region 55 is holding piece 50 below its Curie Point while pieces 20, 30 and 40 are above the Curie Point, so that varying-current applied to conductor 41 causes an induced current in conductor 25, but not in conductor 45.