Differential dilatometer system for twin sample evaluation - has independent suspension for transducer coil and core within stabilised enclosure

摘要

The differential dilatometer is an extensometer which provides simultaneous measurement of dimensional changes in two separate samples. One of the samples has known properties and is sued as a control. A linear transducer comprising a coil and core (54) is mounted on a plate (30) clamped to an Invar (RTM) rod (16). The Invar (RTM) rod is fixed to an end plate of an enclosure (116) which can be filled with a thermostatically-controlled liquid or high-pressure gas. The core and coil of the transducer are independently suspended by pairs of Beryllium Bronze leaf springs (38, 44). Both are connected to individual push rods of similar length which extend into the tip of the probe which is inserted into a furnace. The individual bar samples are held against the respective push rods so that their differential thermal expansion is transmitted to the transducer. A micrometer screw provides zero adjustment.