COMMERCE IN MAIZE GRAIN 599 



direct the air through the layers of grain. It consists of two CHAP, 

 series of racks, of which the upper series constitutes a drying XIL 

 or heating chamber, and the lower a cooling chamber ; these 

 chambers are separated by horizontal steel bulkheads, to pre- 

 vent the mingling of the air, and the racks are fitted with 

 steel slides to confine the grain to the proper chamber. 



The heating chamber is subdivided into two sections, with 

 the heat spaces on .opposite sides of the grain racks. Above 

 the heating chamber is placed a steel garner to contain a sup- 

 ply of grain for the heating chamber, and below the cooling 

 chamber is placed a steel hopper, into which the cool grain 

 is dropped from the cooling chamber. 



The fan and steam coils are placed back of the racks, the 

 fan drawing its air-supply from openings in the front wall of 

 the housing, thence through the racks and grain of the cooling- 

 chamber. It is then forced up through the steam coils, and 

 through the racks and grain in the heating chamber, and out 

 of the drying-house through windows or through ventilators 

 in the roof. The heat given off by the cooling grain is drawn 

 through the fan and discharged into the drying grain, thus 

 utilizing the heat which in other driers is wasted. 



In operating this drier the damp grain is first spouted 

 into the garner at the top of the machine, filling the racks of 

 the heating chamber and the garner. The fan is then started, 

 and the air, heated by the steam coils, is forced through the 

 grain layers till the grain is dry, which ordinarily consumes 

 thirty to forty minutes. The heated air is applied upon both 

 sides of each grain column, treating every individual grain 

 fully and equally. The operator then throws the levers at the 

 bottom of the heating racks, having first closed the slides in 

 the middle of the cooling chamber. This allows the grain in 

 the bottom half of the heating chamber to drop down, filling 

 the top half of the cooling chamber, and at the same time the 

 damp grain in the garner fills the top half of the heating 

 chamber. The motion of the grain in the racks thoroughly 

 mixes the grain, so that every kernel is fully exposed to the 

 drying and cooling currents. 



After another period of drying, the slides in the middle 

 of the cooling chamber are opened, and the grain in botli 

 chambers is allowed to drop, now filling all racks completely ; 



