GB249265A - Improvements in tunnel kilns - Google Patents

Abstract

249,265. Hanley, W. L. Jan. 26, 1925. Tunnel kilns.-A double-track tunnel kiln comprises two firing zones A separated by a partition wall 2 and each fired by a row of furnaces 5 communicating directly with the adjacent zone; means for withdrawing combustion products from each zone, and two end combined preheating and cooling zones A in free communication with the firing zones. As shown, the solid fuel fireplaces 5 are supplied with compressed air by a fan 6 under control of dampers 8, and the products of combustion pass into the heating zones over tapering curved walls 9, which may have baffle ribs 22 on their inner faces. The waste gas outlet ports 11 are situated at the lower end of a wall 9 just above the hearth level and lead through damper-controlled pipes 13 to main flues 14. The top layer of refractory material forming the hearth may consist of hollow slabs 18 which provide horizontal passages in alignment with the pipes 13 and are separated along the median line of the truck to leave a space for the passage of the heating- gases. The slabs 18 have inclined faces so arranged that the two piles of bricks carried thereby will incline slightly towards one another. The firing-zones are separately arched as shown in Fig. 4, while the combined end zones have a single arch. The preheating and cooling zones in the end section may be separated by a screen which does not extend up to the crown and has openings at the bottom to allow for circulation of air. The kiln may be fired by oil or gas instead of by solid fuel.