THE SEPARATION OF THE CRYSTALS. 



Motion is transmitted to the machine by a belt drive on the pulley c, and by 

 the friction cones a and b ; the driving cone a is of steel, and the driven cone b of 

 mill board ; the driving spindle o is carried on two bearings, the cones being 

 kept in contact by the pressure of the spring e on one end of the spindle ; the 

 cones are thrown out of gear by means of the screwed piece d moving the 

 spindle outwards against the pressure of the spring. 



Belt-driven Pivot Machine. In Fig. 202 is shown a type of 

 pivot under-driven machine, which, equally with the above, is common on the 

 Continent of Europe and wherever the influence of Continental engineers is 

 felt. The basket a is fixed to the spindle c, which is supported by the footstep 



FIG. 202. 



bearing /, and the collar formed by the iron bars e ; these bars are screwed 

 up against pieces of indiarubber d. whereby the shock ' of the machine is 

 partly absorbed. The machine is driven by belt drive on the pulley g. 



Weston Suspended Centrifugal. All machines of the types 

 above described use a large part of the power supplied in keeping the 

 revolving basket in a fixed position. In 1852 David Weston invented and 

 made in the Hawaiian Islands the first suspended centrifugal which has since 

 become the standard pattern in cane sugar factories ; beet factories in Europe 

 were (and still are) slow to adopt this pattern. In Fig. 203 is shown a section 

 of the Weston type of centrifugal machine as arranged for belt drive. SB is 

 the suspending block firmly bolted to an overhead beam or framing CF ; EB 

 are elastic buffers resting on the block SB, and above this is suspended from 

 the elastic buffers the spindle IS by means of a top nut and washer; this 

 spindle oscillates with the machine, but does not revolve ; at BB is shown the 

 bottom revolving bearing; at OS is shown the outer revolving spindle attached 



373 



