GB602753A - Improvements in or relating to temperature indicators - Google Patents

Abstract

602,753. Temperature indicators. STEVENS, A. H. (Republic Flow Meters Co.). Aug. 30, 1945, No. 22343. [Class 97 (iii)] The attainment of a predetermined temperature by a transformer or other device is recorded by an indicator comprising a translucent flexible mounting strip 14, temperature-sensitive material 25 carried by the mounting strip and held in intimate association with the surface 10 of the device and melting at the predetermined temperature, an indicating layer 23 of absorbent material, and a shield 26 for preventing false visual indication due to bleeding of said temperature-sensitive material. In the form shown, the temperature-sensitive material 25, on melting, passes through the perforated shield 26 and dissolves the dye 24 which, being absorbed into the layer 23 gives a stain visible through the mounting strip 14. The strip 14 has a sticky inner surface 15 for adhesive engagement with the surface 10 of the device and which is normally protected by a removable guard. The indicating layer 23 may be absorbent paper protected from the sticky surface 15 by a shield 22. The shield 26 may be of suitably treated paper or metal foil and may be perforated or blank. The backing 28 may be of grease-proof paper or metal foil. The discs are fastened together by two adhesive rings 31, 32 of, for example, a viscous solution of sodium silicate. In a modification, the dye is already mixed with the heat-sensitive material. Where the shield is a blank disc, the mixture passes round the edges giving a ring of colour on the indicating disc. Specification 551,783 is referred to.