Abstract: A recycle control is provided for grain dryers of the type which have a drying column area with heating and cooling zones and a recirculating air blower. During a recirculating mode of the grain dryer, the recirculating blower draws in a mixture of cooling air and heating air from the cooling and heating zones respectively and forces the mixture after additional heating back into the heating zone. The recycle control includes an inlet duct and adjustable louver arrangement which during partial recirculating mode selctively flows outside air into the mixture of cooling air and heating air at an intake portion of the recirculating blower to regulate the extent of dryer recirculation, and control grain drying. During a non-recirculating mode the recirculating blower draws in only outside air.

Abstract: An inlet duct is provided for recirculating grain dryers of the type which have a drying column area, and a recirculating blower mounted in a room portion of the dryer, with an open side of the room communicating with the drying column area. The inlet duct is connected with an intake portion of the recirculating blower, and has an open end thereof disposed adjacent to the open side of the room, whereby during a full recirculating condition of the grain dryer, air is drawn into the recirculating blower substantially wholly from the drying column area. The inlet duct has an aerodynamically streamlined interior shape with walls which taper inwardly toward the blower intake portion for efficiently guiding the flow of air from the drying column area directly into the recirculating blower intake.

Abstract: Improved process and apparatus for drying are disclosed whereby a moist granular material is dried by contact with a heated gas and is then cooled by contact with a cooler gas. The cooling gas is supplied to the cooling zone at a pressure which exceeds atmospheric pressure. During passage through the cooling zone, the temperature of the cooling gas is increased, and all of it is then circulated to the heating zone in order to reuse the heat thus absorbed for drying still more granular material. Fuel utilization and drying cost can be substantially reduced, and the invention is especially suitable for use with recirculating grain dryers.