ARTIFICIAL DRYING OF FORAGE CROPS 



JUL 



Conveyor for 

 green forage 



Figure 6. — Revolving-drum drier used in forage-drying experiments at Iberia 

 Livestock Experiment Station. 



3 feet from the end of the outer cylinder. An exhaust fan was con- 

 nected to the outer shell at the furnace end in such a manner as to move 

 the furnace gases together with the chopped hay first through the inner 

 cylinder and then back through the outer cylinder. The dried forage, 

 after passing through the fan, was blown into a cyclone. This 

 reverse-current, or two-pass, system lengthened the evaporating zone 

 and greatly increased the efficiency of the machine. 



The apron-conveyor and double-drum driers were used in drying 

 about 300 tons of hay, including alfalfa, pasture grass, clovers, and 

 soybean hay. Approximately 250 tons were used in feeding tests with 

 dairy animals, and the rest with beef cattle. In operating these ex- 

 perimental driers, records were kept on the tonnage handled, the 

 power, labor, and fuel requirements, and the moisture content of the 

 forage before and after drying. Similar data were obtained from 

 several Louisiana farms where forage driers were being operated. 



Many factors of forage dehydration are difficult to measure pre- 

 cisely. A drying machine handling such a bulky product as forage 

 must of itself be large and attempts to measure air velocities or 

 temperatures or make hydrometric measurements of the drying gases 

 give only approximations. It is impossible to make check runs on the 

 average lot of forage because of the wide range of moisture content 

 within the lot before it enters the drier. The presence of weeds and 

 mixtures of other kinds of forage also affects the data. 



The performances of the apron-conveyor and rotary driers located 

 at the Iberia Livestock Experiment Station were observed especially as 

 to the power, labor, and fuel requirements for various kinds of crops, 

 for crops of different maturity, and for different methods of process- 

 ing. Other factors incidental to these observations were time of the 

 drying run, drier-inlet and exit-gas temperatures, moisture content 

 of forage entering and leaving the drier, the weight of the material 

 entering the drier, and, if possible, the weight of the material leaving 

 the drier. When it was not practicable to obtain the weight of the 

 material on entering and leaving the drier the unknown weight was 

 computed from the known weight and the moisture content of the 

 forage (wet basis) before and after drying. It was assumed that 

 under normal operating conditions the difference between the weight 

 of the forage as it enters and as it leaves the drier represents the water 

 evaporated and that the quantity of dry matter is constant. 



From tests of the two driers at the Iberia Station, which have been 

 summarized in tables 1 and 2, the following is noted : 



