APPARATUS FOR MEASURING HEAT DIFFUSIVITY

摘要

PURPOSE:To accurately measure the heat diffusivity of a specimen plate in the surface direction thereof, by providing a freely movable shield member for shielding the light from a light source. CONSTITUTION:A specimen plate 1 is arranged in a heating furnace 2 and intermittent light with constant amplitude is emitted from a light source 4 through a light pervious window 3. A freely movable shield member 51 and a fixed shield member 52 form an opening part 6 and the shield member 51 is freely moved by a DC motor 8. The light passing through the opening part 6 from the light source 4 is converged to the specimen plate 1 and the actual image of the shield member 51 is formed onto the specimen plate 1. When the motor 8 is rotated and the shield member 51 are moved, the distance from the end edge of the actual image of the shield member 51 formed to the specimen plate 1 to the position of a thermocouple 11 changes and is obtained from the output of an encoder 9. The AC temp. of the specimen plate 1 at that time is obtained from the output of a lock-in amplifier 12 amplifying the output of the thermocouple 11.