218 



CHAPTER XI 



The first patent on a train of mills or " tandem," the term used in Cuba, 

 appears to be found in Rousselot's patent (5050 of 1876). His design con- 

 sisted of a three-roller followed by two two-rollers, the first mill being driven 

 off the engine and the two last by pitch chains. In his patent 2280 of 1878 

 the pitch chain drive is changed to spur and pinion gearing, one engine only 

 being used ; this combination was also patented by Dale (92 of 1885). 



The modern multiple milling train driven by one engine dates from 1892, 

 when a 9-roller single engine mill was erected by the Fulton Iron Works 

 at the Cora plantation of the New Iberville Planting Co., in Louisiana. 

 In districts where American influence was dominant, this rapidly became 

 the standard type with new construction. In various places, especially 

 where capital was scarce, 9-roller trains compounded of already existing 

 units, each unit being separately driven, were erected. These plants may 

 be defined as 9-roller trains in operation, but not in design. 



Perhaps the first 12-roller train was that installed at the Oahu Sugar Co.'s 

 mill in Hawaii in 1906, and formed by the addition of a unit to an existing 

 9-roller train. The success of this change was so very marked that other 

 installations followed. In 1910 the Ewa Mill in the same locality converted 

 two 9-roller trains into a i.5-r oiler train, and eventually into an i8-roller one. 



FIG. 125 



In recent practice the crusher and 9-roller mill are regarded as ineffi- 

 cient. The tendency in Hawaii has been towards the crusher, swing hammer 

 shredder, with or without the use of knives, and 12-roller mill. In Cuba 

 the later mills have adopted the double crusher, followed by fifteen or by 

 eighteen rollers. The writer is inclined to attach importance to the dis- 

 integration of the cane obtained with the swing hammer shredder, and be- 

 lieves that the Hawaiian scheme is better as regards power required and ex- 

 traction obtained, while it is not inferior as regards capacity. 



The Capacity of Mills. By the capacity of a mill is indicated the quantity 

 of material which can be treated in a given time. This is usually stated as 

 so many tons of cane per hour, but the capacity should rather be expressed 

 in tons of fibre per hour. The capacity of a mill or milling plant will also 

 be affected by the efficiency which is demanded of it, and, given a certain 

 quantity of power available in the engine, it is possible from the experimental 

 results given earlier in this chapter to correlate tonnage ground with the 

 percentage of fibre contained in the bagasse after milling. 



Again, the capacity of the plant will depend on the view point of the 

 operator. In some districts a milling plant is regarded solely as a means of 

 grinding cane, in others as a means of extracting sugar from the cane. If 

 conditions exist such that the cultivation has outgrown the factory, relatively 

 large capacities result due to the necessity of taking off the crop. Conditions 



