226 



CHAPTER XI 



to divide this piessure so as to obtain the best results. Evidently the greatest 

 intensity of pressure will be obtained when top and back rolls are set metal 

 to metal and when top and front rolls are set as far apart as possible. The 

 converse arrangement would be to equalize the settings and obtain equal 

 pressures as between top and front and top and back rollers. Practice 

 in the Hawaiian Islands inclines to obtaining a greater intensity of pressure, 



treating the top and front roller 

 as a feeding combination. In 

 Java an opposite opinion holds, 

 and it seems to be considered 

 good practice to equalize the 

 pressures as far as possible. 



Connected with the question 

 of setting is the speed of opera- 

 tion which determines the thick- 



. ^_ . ness of the blanket of bagasse. 



| I In a rigid mill given a constant 



FIG. 133 escribed volume, calculation 



would always indicate the same 



composition in the bagasse, independent of speed. The Java practice 

 however, inclines to thicker blankets of bagasse and slower speeds, generally 

 14 to 15 feet per minute. Hawaiian and Cuban practice has adopted 

 higher speeds, reaching up to a maximum of 30 feet per minute. 



Below are collected certain typical mill settings. The variation between 

 them is so great that perhaps they reflect nothing more than the personal 

 equation of the engineers responsible. 



HAWAIIAN AND ONE JAVAN* MILLS, ALL yS-iN. x 34-iN. OPERATING ON CANE 

 PREPARED BY ONE CRUSHER, AND WITH ALL MlLLS UNDER AN HYDRAULIC LOAD OF 

 CIRCA 450 TONS. 



TONS 

 FIBRE 



ROLLER SETTINGS, INCHES. 



SURFACE SPEED, FT. PER MIN. 



I. 



II. 



III. 



IV. 



Per hour Front. Back. Front. Back. Front. Back. Front. Back. 



5'7 

 7-1 



4'7 

 5'4 



TONS 



FIBRE 



Per hour. 



5'7 

 7'i 

 4'7 

 5'4 



Ii 



ii 



Toe. 



it 



i I 





I. 



20 

 21 

 17 

 19 



II. 



21 



18 



19 



III. IV, 



22 

 20 

 15 



20 



TRASH TURNER SETTINGS. INCHES BELOW TOP ROLLER. 



I. II. III. IV. 



Centre. Heel. Toe. Centre. Heel. Toe. Centre. Heel. Toe. Centre. 



Il It I| Ii Ii If Ii 



If 

 If 



i 



1. 1 



II 



ii- 



2 



Ii 



If 



23 



22 



18 

 1 8 



Heel. 



If 



2 



Ii 



JAVAN RIGID MILLS, 6o-iN. x 30-iN. OPERATING ON CANE PREPARED BY ONE 

 CRUSHER, AND AT A SURFACE SPEED OF CIRCA 14 FT. PER MIN. 



TONS 

 FIBRE 



Per hour. 



3*5 



4'3 



Front. 



T 



ROLLER SETTINGS, INCHES. 



II. 



Front. Back, 

 f 



III. 



Front. Back. 



f i 

 I tt 



I i 



DISTANCE CENTRE OF TRASH TURNER 

 FROM TOP ROLLER, INCHES. 

 I. II. III. 



2 I 



