Modern Gasworks Practice

VERTICAL RETORTS AND CHAMBER OVENS 147 eost for a horizontal plant would be £250-£320 per ton, and in isolated cases less than the lower limit given. (4) In continuously operated types any breakdown in machinery usually entails great inconvenience. So far as the relative merits of the two systems of verticals are concerned, the advocates of th.e continuous type lay claim to the following advantages over the intermittent:— G) QT N a- Gravi ty Bucket Con-veyorwith Trave i7In£-Dumping Chute 'Auxiliary Coal Hopper Coal and _ Coke Hoppers Auxiliary _ Coa!Hopper Fou! Ma/n Seal Pot Producer Ash Chute Coke Discharger Tnavelling Coke Filler for Gravity Bucket Conveyor Fig. 70.—The Woodall-Duckham Vertical Retort System. (1) No air pulled in, becau.se doors of retort are always closed. (2) Quality of gas always constant. (3) Each piece of coal undergoes tlie same treatment. As regards the merits of the intermittent systems, the following points are drawn attention to :—