Temperature gradients in horizontal tube furnaces

✍ Scribed by Joseph H. Flynn; Lee A. Dunlap

• Publisher: Elsevier Science
• Year: 1986
• Tongue: English
• Weight: 250 KB
• Volume: 105
• Category: Article
• ISSN: 0040-6031
• DOI: 10.1016/0040-6031(86)85238-8

✦ Synopsis

Radial temperature differences in a 1 in. diameter horizontal tube furnace similar to those used in thermogravimetry were measured as a function of purge gas flow rate and pressure at temperatures from 25 to 525°C. The temperature difference between a thermocouple at the tube axis and one 0.8 cm off center was 45°C at 4OO"C, 1 atm pressure of nitrogen and 25 ml min-' flow rate. This large temperature difference was attributed to laminar flow conditions.

Effects of these large radial variations on temperature measurement and calibration are discussed. Several methods for minimizing these temperature differences by insertion of in-line preheaters and mixers are suggested.