SUGAE MACHINERY IN PORTO RICO. 



, In a letter to The Times, a correspondent in Porto Rico refers at 

 some length to the sugar-machinery trade in that island. He points out 

 that since the present tariff — free trade for the States and prohibitive 

 duties for all outsiders — ^was enforced there by the United States the 

 importations of sugar machinery from Great Britain have been very 

 small and dependant on special conditions. The Germans, however, still 

 have a good deal of trade with Porto Rico in spite of the high duties; 

 they are the only nation that still compete to any extent with the United 

 States there. The latest American crushing machinery in the island 

 consists of 17-roll sets; i. e., five 3-roll mills and a 2-roll crusher, the 

 whole driven by two engines. An improvement on this is already fore- 

 shadowed in an 18-roll set; i. e., six 'S-roller mills with each of the first 

 two mills having Diamond top roUers. These Diamond rolls have given 

 excellent results, and are, all things considered, much better than a two- 

 roll crusher. 



A further improvement, says this coiTCspondent, would be to drive 

 these eighteen rolls by one steam turbine instead of two reciprocating 

 engines. The turbine arrangement offers no difficulty, and the saving 

 in cost, foundations, steam, oil, and attendance would be considerable. 

 The exhaust steam in a sugar factory is used for evaporating and 

 granulating the cane juice, and the condensations are returned to the 

 boilers. The presence of oil in the exhaust steam from reciprocating 

 motors is therefore very injurious. With turbines this trouble is entirely 

 eliminated. So far as present experience goes, the most perfect sugar 

 factory should have steam motors (turbines) for the milling and electric 

 plants, and all other motors in or connected with the factory should be 

 electric. A single milling set as above indicated can be constructed to 

 work almost automatically, to handle over 2,000 tons of cane per twenty- 

 four hours' work, and, with canes averaging 11-| per cent fiber, to give 

 an average extraction of 85 pounds of juice per 100 pounds of cane, 

 with less attendance than usually required with plants working 300 to 

 400 tons of cane in the twenty-four hours, with an extraction of about 

 75 per cent. 



The largest company expects to turn out this year close on 100,000 short tons 

 of 96° polarization sugars from three factories all connected by railway. The 



' From the International Sugar Journal, vol. 13, No. 149, May, 1911. 



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