THE SEPARATION OF THE CRYSTALS. 



brake pulley ; 30 brake band ; 37 bracket carrying the centrifugal suspended 

 from the I beam 40; 3 and 4 motor case; 10 ball-bearing; 2 water wheel; 

 5 hemispherical caps upon which impinge the water jets 6 and 7 of which 6 

 is the accelerating and 7 is the maintaining jet ; 39 waste pipe ; 25 governor 

 controlling the supply of water when full speed has been obtained ; 27 wire 

 rope links connecting motor to centrifugal. 



These machines are made in pairs with an interlocking gear so designed 

 that only one of a pair of machines can be accelerated to speed at one time. 



In plants of earlier date where the whole battery of centrifugals was 

 driven by belt drive, the whole ratio of gearing between engine and machine is 

 from 300 to 400 to 1 ; with such an arrangement any variation in the 

 speed of the engine is multiplied in the centrifugal and means of varying 

 the speed of a machine or of distributing the power according to the demands 

 on it are impossible ; with the interdependent water and electrically driven 

 machines the power supplied varies according to the demand ; thus with the water 

 drive two jets are employed both of which act when the machine is starting 

 and when the effort is greatest ; afterwards only one jet is in action. A similar 

 principle is embodied in the electric driven machines ; this action is of use 

 too in curing low grade sugars which often are found to purge best when speed 

 is got up slowly ; cost of up-keep and freedom from danger are also points in 

 favour of the direct motor driven types. 



Size of Basket. Within the last decade the size of basket has 

 increased from a standard size of 30 in. to a maximum of 48 in. increase, 

 beyond which it is limited by the size and strength of men ; indeed, a 48 in. 

 machine can only be cared for by a big labourer ; with increase in size of 

 machine, a decrease in the number of revolutions (but not in the peripheral 

 speed) follows. The smaller machines are run at 1,200 to 1,500 revolutions 

 per minute, and the larger at 800 to 1,000. 



Capacity of Machines. A 30 in. suspended Weston machine will 

 produce from 1,600 to 2,0001bs. of dry sugar per hour from a typical first 

 masse cuite ; a 42 in. machine will produce up to 4,000 ; masse cuites however, 

 vary so much, even when boiled from syrups of apparently the same composi- 

 tion, and so much depends on the craft skill of the sugar boiler and curers, 

 that estimates of capacity are of little value ; this is especially so in the case 

 of low sugars ; in addition, the type of sugar made, raw or washed, influences 

 very much the capacity. 



Washed Sugars. The sugars generally made on plantations are 

 shipped to refineries for further treatment and are not washed in the centri- 

 fugal basket ; in Mauritius and Java, however, large quantities of white 

 (^plantation refined') sugars are made for the Indian market and these sugars 



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