Modern Gasworks Practice

VERTICAL RETORTS AND CHAMBER OVENS 191 many ways bear a resemblance to the Munich chambers. Coal, crushed or screened to any size under 6 inches, is delivered to the scraper conveyor situated immediately under the centre line of the roof principals, and the conveyor automatically filis each hopper in turn. to the required volume of coal. Each oven is provided with its own coal hopper, and the charge can be regulated at will; thereby fixing the volume of coal delivered to the oven. The Darwen ovens are constructed of special fireclay material in such a manner that angular thrust is entirely avoided. They are usually 12 inches to 18 inches in width, 8 feet to 11 feet in lieight, and from 20 feet to 30 feet in length, inside ■dimensions. The angle of inclination. is about 42 degrees from the horizontal, thus affording ampie slope for rapid discharge. The chamber content varies from three to eight tons of coal, according to desire, and the carbonizing period is generally twelve or twenty-four hours. The heating flues are angulated in vertical series of five or more, depending upon the vertical lieight of the chamber, and each. heating flue is controlled by its own damper, thereby securing a most effective control of the heating system. Two 10-inch diameter offtakes are provided for each chamber when over five ' tons capacity, and they are so placed. as to remove the gas evolved at the most advantageous position. Both the 10-inch pipes converge to a common “ octopus ” lieader, which also embraces the main delivery pipe to the hydraulic main, thereby necessitating the opening and closing of only one manlid for cleaning all three pipes with augers. The discharge door consists of a heavy swing type door, having faced joints, sealing dry on a faced frame, and securely fastened by means of eccentric balanced hook gear, working on five pin pressed springs operating over two Steel pressure joists. The leverage effects a distributed pressure of close on 20 tons, which is found to give a peifect fitting door. The door frame is fastened to the oven front by means of pressure pins transferring thrust on to the heavy buckstays, four in number, and 18 inches X 8 inches X f-inch. The joint is made with asbestos rope and special fireclay material, reposing in concave joints contained in the. oven con-struction. The opening and closing of the door is merely a matter of a lifting hook, which automatically engages a cross bar, and by lifting on this bar the door releases itself ; and, by lowering, automatically closes and locks itself. No hånd labour is required. So soon as the door is lifted the charge of incandescent coke mshes out of the oven on to the conveyor quencher. In case a charge of coke hangs up, by reason of non-scurfing, a small ram machine is provided to traverse between the twin chambers. This machine carries two rams working as illustrated, and which are electrically operated by means of a motor taking current from leads and a trolley arrangement concealed and fool-proof. In some cases the ram framing carries a coke or breeze hopper feed for gas producers on the stage below, thus avoiding separate feed hoppers for coke for producers. Charging an oven occupies twenty-eight seconds for eight tons, the entire operation of discharging and charging occupying only one and a half minutes.