| 摘要 |
1422689 Firing ceramic products BOC INTERNATIONAL Ltd 13 June 1974 [13 June 1973] 28243/73 Heading F4B The heat treatment of ceramic or clay products comprises introducing the products into a kiln, burning fuel in the kiln and supporting the combustion by supplying pure oxygen or a nitrogen/oxygen or like mixture containing more oxygen than does the atmosphere. The kiln may be continuous or of the batch type and the fuel solid, liquid or gaseous, suitable fuels including fuel oils, natural gas or liquefied gases such as LPG, propane or butane. The oxygen content may be 22-31% by volume, preferably 23-25%, and the increase is supplied to the burner or if there is more than one burner, to a selected burner or burners during the stages of a heating cycle when there is no significant restriction on the rate of heating of the products, e.g. when no molecular change is taking place in the products. It is desirable that the fuel is fully oxidized without an excess of oxygen so that the rate of supply of oxygen to any or each burner should be the minimum required for complete combustion whether the burner is operating on air or the aforementioned mixture. The extra oxygen may be supplied to the combustion region of a burner or may be premixed with the air. |
