MACKEXSEX DRYER. 179 



considered to be standard and practical in working. These are 

 .the Mackensen, the Petry & Hecking and the Buttner & Meyer. 



With the Mackensen apparatus several hundred tons of cos- Mackensen 

 settes directly from the presses may be dried per diem. This dryer- 

 apparatus consists of two long drums in forged iron (I and 

 II), about 43 feet in length and 4J feet in diameter, each 

 of which is composed of three sections, having iron rings 

 at each of their extremities, and working on trolleys. Their 

 rotatory movement corresponds to a velocity of five to six 

 revolutions per minute. The pressed cossettes fall by K into * 

 the first drum, passing through the same very slowly, and the 

 hot gases from the furnace move in the same direction. In the 

 first drum the temperature of these gases is about 140 tq 150 C. 

 The motion of the cossettes is produced partly by the current of 

 hot gases that carry them and also by a heating apparatus ar- 

 ranged as a spiral inside of the appliance. The early arrange- 

 ment had a fire-grate, over which air passed, in front of each 

 cylinder. At E they fall into an oblique spiral, H, which raises 

 and compels them to fall into the second drum, where the tem- 

 perature is about 230 F. The hot gases are drawn off by the 

 so-called exhauster, Af, and penetrate a dust chamber where the 

 pulps that have been carried forward arc deposited. The cos- 

 settes on entering the second drum contain 50 per cent, to 60 

 per cent, moisture. They give up their remaining moisture on 

 entering the second drum, II, and fall upon the spiral, F, which 

 conducts them to the elevator, by means of which they are car- 

 ried to the loft or store-room. Two drums are sufficient for a 

 factory slicing 150 tons of beets per diem. The motive power 

 for all the drums, spirals, lifts, etc., is not more than 15 to 20 

 horse-power. The entire plant does not mean an expenditure 

 of more than 55,000 marks to 60,000 marks [813,500 to 815,- 

 000], including building, chimneys, etc. 



Residuum having originally 85 to 90 per cent, water, retains 

 only 8 to 12 per cent, when the operation is complete. Con- 

 sumption of coal is about 180 to 220 Ibs. per 100 Ibs. of residuum 

 dried. In Germany, the product finds a ready market at about 

 827 per ton. The actual cost of the method is $16.80 per ton 

 of dried product obtained. The daily production being 18 tons, 



