228 



CHAPTER XI 



arrangement is also seen in Payen's mill, referred to in books of date 



about 1850. 



The De Mornay patent is 13709 of 1851; the improved form due to 



Chapman (4209 of 1888) is shown in Fig.. 

 134, and of this a number have been 

 built, some stiU remaining in operation. 

 In most of these patents it is easy to 

 see that the conception of the patentee 

 was to improve the extraction of the 

 mill, the idea of the train of mills not 

 having then been conceived. 



The Two-Roller Mill.— The 2-roller 

 mill, as shown in Fig. 135, followed the 

 3-r oiler, and was brought out as a re- 

 pressing or macerating mill, and also 

 with the object of eliminating the trash 

 turner. Chapman's patent (441 1 of 

 1875) claimed the 2-roller mill in con- 

 nection with Russel's maceration scheme 

 (4094 of 1874), and a very similar patent 

 was taken out by Rousselot (5050 of 1876). In a later patent (2280 of 1878), 

 Rousselot added a small feed roller to the 2-roller, as shown in Fig. 136. At 

 the same time the 2-roller miU was developed by Alexander Young in the 

 Hawaiian Islands. Difficulty in feeding whilst maintaining the pressure 

 prevented the adoption of this type. To overcome this trouble the forced 

 feed of Riley (patent 17776 of 1891) was tried, Fig. 137. In this device a 

 reciprocating pusher bar, a, is driven from an eccentric or crank through 

 a rocking shaft b, and forces the bagasse into the miU. 



Very similar arrangements were patented later by Fletcher (161 18 of 

 1892) and Kidd (15301 of 1893). The , 



2-roller mill has disappeared from X 



modern practice, and a number which 

 were installed are doing duty as 

 crushers. 



Preparation of Cane for Milling. — 



The cane may be considered as a 

 hollow cyhnder reinforced by trans- 

 verse partitions (the nodes). Such 

 a structure is well adapted to resist 

 an external pressure. Rupture of 

 the cylinder, combined with a ren- 

 dering of the cane into a fine state 

 of division, is the object of the de- 

 vices used to prepare the cane for 

 milling. These devices may be 

 classed as saws, knives, shredders, 

 crushers, and hammers. The first- 

 named class has never come into extended use, and at most has been applied 

 only in isolated cases. 



The earliest British patent on this matter was issued to Blanchard 



Fig. 137 



