Grain dryer

A concurrent-countercurrent flow grain dryer comprising a tower with side walls, a top and a bottom, said tower having a wet grain receiving bin at the top, said bin having a horizontal floor assembly extending across between the side walls of the tower, said floor assembly having a plurality of substantially uniformly spaced openings extending over substantially the entire floor assembly with a wet grain delivery tube member fixed beneath each said opening, each said tube member having heat insulating side walls and, serving to deliver wet grain in response to gravity from said receiving bin into a drying chamber located in the tower beneath the bin, said drying chamber having a plurality of grain discharge outlets extending across the bottom thereof and means for withdrawing dry grain from said grain outlets at a controlled rate, a hot air inlet duct adjacent said tube members adapted to deliver hot air into the spaces between said tube members and downwardly through a bed of grain in said drying chamber, cooling air inlet ducts extending across the bottom of said drying chamber for directing cooling air upwardly through the bed of grain, exhaust ducts extending across said chamber intermediate said hot and cooling air inlet ducts to receive and exhaust air flowing from said hot inlet duct in a concurrent direction to grain flow and to receive and exhaust cooling air flowing from said cooling air inlet ducts in a countercurrent direction to grain flow, and means for providing hot air to said hot air inlet duct and cooling air to said cooling air inlet ducts, the improvement which comprises wet grain delivery tube members having substantially equal transverse dimensions of no more than about 16 inches, said tube members being spaced from each other a distance no greater than twice the said transverse dimensions.

A concurrent-countercurrent flow grain dryer comprising a tower with side walls, a top and a bottom, said tower having a wet grain receiving bin at the top, said bin having a horizontal floor assembly extending across between the side walls of the tower, said floor assembly having a plurality of substantially uniformly spaced openings extending over substantially the entire floor assembly with a wet grain delivery tube member fixed beneath each said opening, the tube members being rectangular in transverse cross-section and spaced from each other a distance no greater than twice the width of each tube and serving to deliver wet grain in response to gravity from said receiving bin into a drying chamber located in the tower beneath the bin, said drying chamber having a plurality of grain discharge outlets extending across the bottom thereof and means for withdrawing dry grain from said grain outlets at a controlled rate, a hot air inlet duct adjacent said tube members adapted to deliver hot air into the spaces between said tube members and downwardly through a bed of grain in said drying chamber, cooling air inlet ducts extending across the bottom of said drying chamber for directing cooling air upwardly through the bed of grain, exhaust ducts extending across said chamber intermediate said hot and cooling air inlet ducts to receive and exhaust air flowing from said hot inlet duct in a concurrent direction to grain flow and to receive and exhaust cooling air flowing from said cooling air inlet ducts in a countercurrent direction to grain flow, and means for providing hot air to said hot air inlet duct and cooling air to said cooling air inlet ducts, said tube members being of a size and spacing from each other such that the wet grain is delivered through the tube members into the drying chamber with a pulsating action and the wet grain flowing into the drying chamber forms a layer over the entire area between the tube members during each pulsation.