352 Journal of Agriculture, Victoria. [11 June, 1917. 



obtain as mucli semolina and middlings as possible on the first and 

 second breaks, witbout cutting up the bran or making break flour and 

 bran dust. When this is done, the feed to the third break will be broad 

 and thin, and the middlings adhering may be removed on this break. 

 The stock coming to the bran roll will have some flour adhering, which 

 will require very little pressure to release. A small percentage of flour 

 will be separated, and clean broad bran will tail over from the bran 

 duster. On the breaks, as well as on the reductions, the exhaust should 

 be adjusted to remove the hot air without drawing oS any of the good 

 stock through excessive suction. Heating of the rolls should not be per- 

 mitted, as keeping the stock cool makes for a better finished flour. 

 Cutting up of the branny particles must be avoided, or the purifiers 

 will be overworked, and a low-grade flour be the result. The first, 

 second, and third break rolls are run at a differential of 2^ to 1, with 

 a speed of .3.50 revolutions per minute, and the fourth break roll at a 

 differential of 3 to 1, with a speed of 450 revolutions per minute, the 

 rolls Ijeing grooved as follows: — First break, 12; second, 14; third, 20; 

 and the fourth, 26 grooves to the inch. 



Reductions. 



The reduction rolls are' usually numbered in alphabetical order 

 from A to L. Stock as it reaches the reduction rolls should be granular 

 and as pure as it is possible to make it. The best stock should grade 

 on to C roll. This roll has the largest grinding surface of any of the 

 reduction rolls. At least, 20 per cent, of the flour, or approximately 

 50 per cent, of patents, should be made on it. The roll surface necessary 

 on each reduction roll in order to mill Australian wheat at the rate of 

 500 lbs. ner hour would be approximately — A, 7"; B, 9"; C, 11"; 

 B2, 3 ; D, 7"; E, 5"; F, 5"; G, 4"; H, 3"; I, 3"; K, 3"; L, 3"; 

 total, 63 inches. 



The feed sent to A reduction is the bulk of the semolina. This 

 should be bright, clean, and .sharp in appearance, and free from branny 

 particles. The object to be attained on this roll is to grade the coarse 

 •semolina, allowing as much as possible to pass on to C roll, without 

 releasing a high percentage of flour. A better quality of flour is got 

 through giving the feed this double treatment. Attempting to reduce 

 the stock in one operation would lower the quality and the strength of 

 the flour. The roll should be set, to return a sharp grind, not less 

 granular than the C feed. The offal will consist largely of germ that 

 has been flattened out, and mil be easily removed by the purifiers. 



The feed sent to B reduction is the throughs of the middlings' 

 purifiers, except those from the tails and the head sheets of these purifiers. 

 The same method of grinding is carried out here as at A roll in order 

 to make stock for C roll. The grind will be more even and finer and 

 comparatively sharp. Provided the purifiers are doing their work 

 satisfactorily, very little impurity and more flour of a better quality 

 will be made here than at A roll. 



B^ roll is required to deal with the tails from B redresser and the 

 throughs of the tail sheets of the third break purifiers. 



The stock graded on to C roll should be small, sharp, and free from 

 impurities. The grind should be soft, and the hardness only detected 



