GB332619A - Improvements in or relating to continuous kilns - Google Patents

Abstract

332,619. Robertson, H. M. Jan. 23, 1929. Tunned kilns. - In a tunnel kiln having side combustion chambers from which the gases flow into the tunnel through perforated walls 33, the waste gases are withdrawn at the inlet end through openings 43 spaced over the height of the tunnel. The kiln shown comprises entrance, preheating, firing, and main and supplementary cooling sections 5, 3, 2, 4, and 6 respectively, and is heated by fireplaces 18 delivering into secondary combustion chambers 24 having perforated walls 33 on the sides facing the tunnel. The firerlaces shown, which are adapted for use with gas or oil burners, have inclined rear walls 18b. and with them are associated passages 25 for heating secondary air supplied to the combustion chambers. A further supply of hot air is admitted at the cooling-chamber ends of the combustion chambers from pipes 30 extending the length of the main cooling chamber 4 between headers 26, 29, the latter of which is in communication with the atmosphere. Grates for solid fuel may be fitted in the fireplaces. Transverse baffles or piers 14, 15, 16 are fitted in the preheating, firing, and cooling zones respectively for preventing longitudinal flow of gases along the sides of the tunnel and for promoting a transverse circulation amongst the goods. The damper-controlled outlet openings 43 are formed in the three piers 14 nearest the inlet end of the kiln. In the final cooling-zone 6 pipes 52 extend vertically along the side walls and horizontally beneath the roof, and these pipes are connected to lower headers 51 with air inlet connections 54 and to an upper header 53 with an outlet connection 55. The inner walls of the tunnel are formed to provide bench supports 12 for the combustion chambers 24 &c., and between these inner walls and the outer walls 7 is a laver of heat-insulating material 10. The running parts of the trucks are cooled by air pipes 21 extending in both directions from an inlet header 22 at about the middle of the firing-zone, and the pipes are protected by ledges 20 on the side walls. The supporting-platform 61 for the goods is made up of a number of spaced sections, and between it and the body portion 59 of the truck are circuitous passages 62 for the heating-gases.