232 



CHAPTER XI 



by Messchaert (patent 8162 of 1914) . These are deep circumferential grooves 

 about i^-in. or if-in. by i\i-in., spaced about 4 inches apart. They are 

 placed on the feed roller, and serve to conduct away the juice expressed by 

 top and feed roller. Otherwise this juice cannot freely escape, and diffi- 

 culties in feeding occur which are often attributed to the setting of the trash 

 turner. The introduction of this system has been attended with increased 

 capacity, increased exti-action, and remarkably low water content of the 

 bagasse (especially when applied simultaneously to the back roller), and the 

 possibility of using very large quantities of imbibition water without 

 choking the mill. In many districts this system has become standard 

 practice. That the full benefit may be obtained from these grooves, it is 

 necessary that they be kept free from bagasse ; they are therefore operated in 

 combination with scrapers usually attached to a bar bolted to the housings. 



Control of Mill Operations. — In the modern cane mill the only non-rigid 

 clement is the top roller, which lifts in proportion to the quantity of material 



passing. A record of this move- 

 ment will then give a measure of 

 the quantity of cane passing at 

 any moment, of the regularity of 

 the feed, of any change in the 

 nature of the cane, of the sensi- 

 tiveness of the movement (or 

 freedom with which the hydraulic 

 ram operates), and of the times at 

 which the mill starts and stops. 

 The apparatus of Deerr (patent 

 6574 of 1915), Plate XXIII, con- 

 sists of a rod attached at E to the 

 top brass of the top roller, which 

 moves with the movement of the 

 latter. By means of a parallel 

 motion similar to that employed 

 on steam engine indicators, this 

 vertical movement is multiplied 

 and recorded on the chart on the 

 drum A , eight inches in diameter, 

 which makes one revolution in twenty-four hours. The recording apparatus 

 is carried on the adjustable system, B, C, D, and the connecting rod passes 

 through a stuffing box, F, designed to give if any undue strain is placed 

 thereon. 



Algebraical Analysis of the Process of Milling.— Consider the cane as 

 porous material, the fibre, which has soaked up and holds by means of 

 capillary attraction a liquid, the juice. On the application of pressure to this 

 material the juice is expressed, and eventually a point is reached when pressure 

 fails to afford any more juice. This operation will be referred to as the " dry 

 crushing," and the resultant residue of bagasse as the " dry crushed bagasse." 

 The second process consists of the addition of water to the dry crushed 

 bagasse, which water mixes with and dilutes the residual juice. On again 

 applying pressure a dilute juice is obtained, and bj^ continuing the process 

 eventually all the sugar present in the cane may be obtained. The bagasse 

 resulting from such operations will he referred to as the " wet crushed 



Fig. 



142 



