ARTIFICIAL DRYING OF FORAGE CROPS 21 



Meal is sometimes blended to obtain a desired protein and carotene 

 analysis. If this is done at time of dehydration and before sacking 

 operations, considerable savings in labor and cost can be made. 



Crushers are sometimes used to reduce the chopped green forage to 

 a small uniform size to promote faster and more uniform drying. This 

 equipment is placed between the automatic feeder and drying chamber. 



The following points should be kept in mind regarding drier opera- 

 tion : 



1. For a drum drier the forage should be reduced to a uniform size, 

 the size of the particles not being greater than about three-eighths of 

 an inch in any one dimension. 



2. The inlet temperature should be kept as high as possible, pref- 

 erably around 1,400° to 1,500° F. Temperatures in excess of these can 

 be used, but corrosion of the brick and steel work may occur more 

 readily at temperatures in excess of 1,500°. 



3. The temperature of the exhaust gases should range between 225° 

 and 325° F. for a drum drier, depending upon the initial moisture 

 content of the forage. 



4. The furnace, drum, fans, and cyclones should be close-coupled 

 to eliminate piping resistance. 



5. Fenumatic conveyors for chopped forage require slightly more 

 power than do drag conveyors. Pneumatic conveying of the dried 

 product allows greater flexibility than do drag methods. However, 

 from the standpoint of fire prevention, any smoldering sparks of 

 forage will be more readily detected in the open conveyor than in other 

 systems of conveying. In any case the stored product should be 

 watched for several days. For horizontal runs of pneumatic systems 

 the air velocity should be about 4,000 feet per minute. 



6. The matter of fire prevention is important at the forage- drying 

 plant. Unforeseen stoppages and breakdowns may result in fire out- 

 break. Convenient garden-hose connections with short pieces of hose 

 will pay for themselves many times over in extinguishing fires as they 

 begin. If water under pressure is not available, water barrels with 

 hand-pump tanks should be on hand. In addition, installation of a 

 20-pound dry-powder type hand fire extinguisher is recommended for 

 use on electrical or oil fires. Forage driers should not be placed in 

 barns or buildings where quantities of inflammable farm products are 

 stored. An inexpensive fire-resistant shelter for the drying plant can 

 be made from second-hand steel pipe and corrugated sheet-metal 

 roofing. 



7. It is very important that the forage be thoroughly dried down 

 to its safekeeping moisture content, which for practical purposes 

 should approximate 8 to 9 percent. Too often the inexperienced 

 operator attempts to increase the output of the drier beyond its capac- 

 ity without due regard to the heat input. The result is a partially 

 dried product that may mold or may heat sufficiently to cause spon- 

 taneous combustion. Whole field-cured hay usually can be stored with 

 a moisture content of from 15 to 25 percent, depending upon locality, 

 without danger of heating. Experience indicates that artificially 

 dried hay, especially when chopped, should have a lower moisture con- 

 tent. Such material, when conveyed directly to a bin from the drier, 

 has a higher temperature than that of the atmosphere and there is 

 likely to be some variation in the moisture content of the particles. 



