Microcomputer‐controlled furnace for obtaining dynamic thermogravimetric measurements

• Published in: Review of scientific instruments 1984-08, Vol.55 (8), p.1336-1342
• Main Authors: Gleixner, R. A., Green, M. J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Metering, regulation, automation in energy; Physics; Theoretical studies. Data and constants. Metering; Thermal instruments, apparatus and techniques
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.1137936

A cyclic thermogravimetric apparatus has been developed for reliable measurement of the equilibrium decomposition pressures of metal carbonates. The measurement technique involves suspending a sample from a microbalance inside a reaction vessel which in turn is supported vertically inside a furnace. An atmosphere of argon and carbon dioxide flows through the reaction vessel and the furnace temperature is varied periodically about a preset temperature, while the mass and temperature of the sample are monitored. The equilibrium decomposition temperature for a given partial pressure of CO2 is the mean temperature of that temperature cycle which produces a symmetrical mass variation with no net mass change. The method for controlling the furnace using a Rockwell AIM‐65 microcomputer is described in detail. The equilibrium pressure of calcium carbonate, which has been studied extensively by other workers, was measured to test the performance of the system.