Technical Requirements for the Measurement Section of a Thermal Expansion Coefficient Tester

A thermal expansion coefficient tester uses computer control, intelligent PID regulation, and a modular architecture to monitor and control displacement and temperature throughout the experiment. It supports offline operation and automated testing when connected to a computer. The instrument is designed to measure the high-temperature thermal expansion coefficients of carbon fibers and their products, metal alloys, glass, ceramics, refractories, and other polymer composites. 1) Base dilatometer system: Available in vertical or horizontal configurations, equipped with an integrated measurement amplifier and an inductive displacement sensor with an alloy probe head. It features a vacuum-sealed structure and a thermostatic water bath to protect the sensor base. The probe head position is adjustable with high-precision contact force control. Measurement range: 5000 μm; resolution: 0.1 μm; contact force of probe head: 15–45 cN. Adjustable sample length: 25–50 mm. Sample size and temperature range depend on the chosen sample holder, furnace, and protective tube; sample diameter: 5–10 mm. Sample holders are available in quartz, alumina (Al2O3), and graphite. 2) High-temperature tube furnace: Includes a heater, S-type control thermocouple, and a fan. Available operating temperature ranges include: -196 ℃ to 200 ℃, -40–600 ℃, room temperature to 1000 ℃, room temperature to 1600 ℃, room temperature to 1700 ℃, and room temperature to 2000 ℃. 3) Furnace and cryogenic configuration: The high-temperature tube furnace includes a protective tube for gas flow with a support flange. For low-temperature operation, a liquid nitrogen cooling Dewar is used. The sample and holder are immersed in the LN2 Dewar; a piston pushrod drives the core of the inductive displacement gauge to move, generating a potential difference. This signal is amplified into a voltage, sent to a data acquisition unit, and then processed by computer. 4) Power supply for the furnace: 2.0 kVA with an enclosure. 5) Sample holder assembly: Supports sample lengths from 0–50 mm and a maximum sample diameter of 10 mm. Includes sleeve, pushrod, and sample thermocouple. Thermocouple types are selected by temperature requirement (K, E, R, S, B, W-Re, etc.). 6) Gas outlet return line: Equipped with corrosion-resistant premium steel valves and gas plugs, including supports. 7) Thermostatic circulating water bath: Includes refrigeration with cooling capacity of 260 W at 20 ℃ (heating power 2000 W). Temperature stability: ±0.01 K. Multi-function display, supplied with 10 m hoses and connection components. Power: 230 V / 50 Hz.

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