| 摘要 |
1294353 Porous refractories SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 25 June 1970 [27 June 1969] 32546/69 Heading C1J A radiant heating porous ceramic element comprises a permeable core of one or more gradings of a refractory having a complete lateral casing of a dense grading of the same refractory, the core and casing being integrated after sintering. Alumina and a zirconium compound are stated refractories. The core is formed first by mixing the refractory with cement and water, casting, air curing, sintering and cooling. The same steps are then applied to the dense refractory mix which is cast around the core. |
