8 BULLETIN 921, U. S. DEPARTMENT OF AGRICULTURE. 



2. The method employed by the owners of small steam factories 

 in regions outside of Louisiana. A number of these factories, scat- 

 tered throughout the entire Gulf coastal region from Texas to 

 Florida, operate by the general method which the individual farmer 

 employs with his small equipment, but use steam power and steam- 

 heated coils for evaporating the juice to sirup. They vary in ca- 

 pacity from a few hundred to several thousand gallons per day. 



3. The method employed in Louisiana for making sirup. Here, 

 too, the power is furnished by steam and evaporation is effected by 

 steam-heated coils, but this method differs from the others in that 

 lime and the fumes of burning sulphur are added to the juice to 

 effect clarification, and, in addition to skimming the heated juice, 

 settling tanks are provided in which the material is allowed to settle 

 out. The capacities of the Louisiana sirup factories are usually 

 much larger than those of the factories in the other States of our 

 sirup-producing area. 



Since the farmers employing the first method of sirup making 

 operate on a very small scale and with simple equipment, it is hardly 

 probable that the method of clarification described in this bulletin 

 will be practicable for them. For this reason a comparison will be 

 made between this method and the other two methods, where the 

 sirup making is conducted on a factory or semi-factory scale. 



For comparison we will consider a plant of 50 tons daily (24 

 hours) capacity, operating by the simple method of clarification in- 

 volving skimming only. A plant of this type usually has a vat 

 fitted with steam coils into which the juice runs direct from the mill. 

 Here the juice is heated until the thick blanket of scum which rises 

 begins to crack. The heat is then turned off and this blanket of 

 scum is removed by skimming. From this clarifying vat the juice 

 is run directly to one or more evaporators, where it is immediately 

 cooked to sirup, additional scum being removed during the evapora- 

 tion. The changes and additions to such a plant for the purpose of 

 using infusorial earth clarification would be appreciable, namely — 



(a) Filter presses totaling about 200 square feet in filtering area. 

 It is estimated from experimental results obtained with the 18-inch 

 filter press that 200 square feet of filtering area will handle the 

 juice from 50 tons of cane in 24 hours. In actual experiment, using 

 11 pounds of infusorial earth to 1 ton of cane, the juice from 6 tons 

 was handled in 4 hours. Suppose, for good measure, that 6 hours 

 were required for handling 6 tons with 80 square feet of filtering 

 area, then in 24 hours with 80 square feet, 24 tons could be handled, 

 and by doubling the filtering area, or with 160 square feet, 48 tons 

 could be handled. To make the estimate liberal an additional 40 



