Vacuum formed, ceramic fibre furnace modules: process improvement and product properties

The vacuum forming of ceramic fibre composites is a cost effective method o f producing modular furnace linings. A typical industrial process is descri bed and the results for the density, thermal conductivity, and fibre struct ure as affected by process variables are presented. A statistically designe d experiment to determine which of 15 process variables significantly affec ted important product properties is described. This showed that vacuum form ing time and oven drying temperature significantly affect product mass, as anticipated and that the vacuum forming pressure, vacuum drying time, and m ould mesh size significantly affect in-service volume shrinkage at 1200 deg rees C. Tentatively, the results indicate that mould mesh size affects ther mal conductivity at 1200 degrees C on initial thermal exposure and that vac uum forming pressure effects thermal conductivity after exposure at 1200 de grees C for 3 weeks. A strategy to determine optimum values for these signi ficant variables is suggested, the remaining variables being set at values for minimum production cost. BCT/188. (C) 1998 The Institute of Materials.