GB414610A - Improvements in tunnel kilns - Google Patents

Abstract

414,610. Tunnel kilns. SHOOK, T. W., Kingsway Chambers, Kingsway, Stoke-on- Trent. March 13, 1934, No. 7878. [Class 51 (ii).] In a tunnel kiln having side combustion chambers 14 shut off from the ware tunnel by heat-radiating plates 8, cold air is supplied under controlled pressure by a fan 40 to the cooling zone 12, and, after being heated by contact with the outgoing goods, is circulated through the ware in the heating zone 11 and finally passed to the combustion chambers 14 to support combustion therein. As shown in Fig. 2, the air passes downwardly through apertures 36 in the ware-supporting platforms 22 to flues 35 in the trucks 15 and from thence to spaced passages 29 and to side flues 32. The main burners 18 induce secondary air, in quantities controlled by dampers 30, 31, from both the passages 29 and the flues 32, while the latter also supply secondary air, through passages 33 controlled by dampers 34, to auxiliary burners 20 which deliver directly on to muffle blocks 21 having an inclined face to radiate heat on to the undersides of the platforms 22. Primary air is supplied to the burners 18, 20, by a fan 39, Fig. 1<a>, which is in communication with the side air flues 32. The burners 18, 20 are staggered on opposite sides of the tunnel, and relief ports 5 are provided to permit the escape of a portion of the circulating air ; this escaping air may be led to the fan 39 or used for drying or other purposes. The waste gases pass along the combustion chambers 14 to exhaust flues 47 at the inlet end of the kiln, these flues being connected to an exhausting fan 17 and also communicating, through damper-controlled openings 46, with the tunnel so as to provide for the withdrawal of water vapour &c. given off in the preheating zone 10. Dampers 19 are arranged between the ends of the combustion chambers 14 and the exhaust flues 47. The fan 40 also supplies air through a branch 43 to a flue extending over the roof of the cooling zone 12, the air thus heated being supplied through an external pipe to slots in the crown of the preheating zone 10. Rubbing seals, formed by insets 24, 25 of insulating material, are provided between the platforms 22 and the muffle blocks 21 and between the bodies of the trucks 15 and the lower side walls of the tunnel ; the trucks also carry sealing plates 48 co-operating with sand troughs 49.