GB371440A - Improvements in and relating to the firing of ceramic materials - Google Patents

Abstract

371,440. Tunnel kilns. POLLAK, J. E., 20, Holborn, London.-(Porzellanfabrik Kahla; Kahla, Thuringia, Germany.) Jan. 22, 1931, No. 2198. [Class 51 (ii).] In a process for firing pressed ceramic material and recovering oil therefrom, the material is heated in a chamber built into a furnace and separated from the remainder of it, until the oil in the material is evaporated, the oil being led off for utilization, any final firing of the material that is required then being effected in a subsequent heating stage of the furnace. In the tunnel kiln shown, the oil evaporation zone or chamber is formed bv the walls o and doors d, e which can be raised and are counterbalanced. An excess pressure is produced in the chamber by blowing air into it through pipes l, m to prevent entry of combustion gases. The mixture of oil vapour and air is drawn off through a pipe n, and may be utilized, together with other fuel, to supply the burners f for heating the furnace. The wagons 1 .. 5 are in the water evaporation zone, 6 .. 9 in the oil evaporation zone, 10 .. 13 in the heating zone, and 14 .. 20 in the cooling zone. If the heating zone is not necessary, the burners may be disposed laterally of the wagons 8, 9. Air warmed in the cooling zone may be used to supply the conduits l, m, and for combustion. In a single furnace, the material is directly heated to drive off the water, indirectly heated to evaporate the oil, and finally directly or indirectly heated, or allowed to cool.