Improvements in or relating to resistance thermometer elements

Abstract

Abstract 475,667. Wire resistances. ELLIOTT BROS. (LONDON), Ltd., HARBEN, D. C., and COLLINS, F. G. June 6, 1936, No. 15920. [Class 37] [Also in Group XX] A wire resistance element for a resistance thermometer is wound on a support of consolidated alumina and the support and resistance wire are embedded in a layer of consolidated alumina. Alumina powder is mixed with distilled water to form a paste, which is extruded through an orifice to form a rod. This is cut to the required length to form the support 1, Fig. 1, and two platinum wires 2 are inserted into one end to form leadin connections. The support is then baked or sintered at about 1500‹ C. Platinum resistance wire 3 is wound non-inductively on the support, the ends being welded to the leadin wires 2. The element is then annealed for thirty-six hours at about 1000‹C and gradually cooled. The resistance is then adjusted to the required value and a layer 4 of the alumina paste is applied and dried at about 200‹ C. Glaze 5 is then applied to the outer surface and the element is fired at 900‹ C. for 15 minutes. The lead-in wires may alternatively be bent as shown at 6, Fig. 2.

Inventors

No inventors recorded.

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