THE EXTRACTION OF JUICE BY MILLS. 



The engines used to drive sugar mills are either beam engines or horizontal 

 engines; generally, owing to the type of labour available, the design of the 

 engines is as simple as possible. Whether beam or horizontal, they are nearly 

 always simple non-condensing engines, the exhaust steam being used in evapora- 

 tion. Beam engines make a handsome ornament to a factory, but they are more 

 expensive in first cost ; their cylinders, however, do not require re-boring. The 

 horizontal engines used are nearly always single cylinder engines ; occasionally, 

 when the engine is at a dead centre, the cane mill chokes, and it may be necessary 

 to lever the fly-wheel round to allow the engine to re-start. A two- cylinder 

 engine, with cranks set at right angles, would overcome this difficulty, and the 

 writer has seen such an installation at work in a modern mill ; but in all the 

 recently erected mills in the Hawaiian Islands single cylinder non-condensing 

 engines of the Corliss type have been erected. 



FIG. ill. 



The Gearing of Mills. The intermediate gearing which transmits 

 power from the engine to the mill consists of heavy toothed wheels ; occasionally 

 helical teeth are employed. Except in small mills the spur wheels are built up 

 in segments ; usually there are from six to eight arms, to which are bolted the 

 segments of the gearing ; the pinions are cast in one piece, and are usually half 

 shrouded. In Figs. 112 and 113 are shown two methods of connecting up the 

 gearing of a single motor nine-roller mill; a is the fly-wheel, J L the first motion 

 pinion, c l the first motion spur wheel, b 2 and c 2 the second motion pinion and 

 spur wheel. In Figs. 112 and 113, b t transmits motion to both spur wheels, 



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