GB955830A - Improvements relating to demonstration and display devices - Google Patents

Abstract

955, 830. Temperature indicators. A. STRICKLER. June 25, 1960, No. 22339/60 Heading G1D. [Also in Divisions G2 and G5] In a device for demonstrating various heating effects a thin support layer 33 has spaced members 35, 38, 40, secured to its rear surface to define a pattern and inject heat into the support layer, and a layer 34 on its front surface which changes colour reversibly with temperature to show visibly the heating provided by members 35, 38, 40. The layer 33 may be not thicker than 0. 001 inch and of highly porous, low density material such as paper, cellular polystyrene, pith, or cork. The members 35, 38, 40 may have different reflection characteristics and be partially coated with paint 36 or aluminium foil 39 and co-operate with a radiant heat source. Alternatively the spaced members may be of different thermal conductivities and be associated with a source of direct heat. In further forms, the spaced members may be resistors in an electrical circuit. To prevent darkening of the thermosensitive layer 34 due to prolonged exposure to bright light, a filter, (see Division G2) may be provided either associated with the light source or deposited on, or laminated to, the layer 34. The device may be provided with struts Fig. 4, (not shown) forming a parallelogram construction so that with base and supporting rear member it may be folded flat or stood upright.