A grain dryer has pair of heating columns in communication with an upper plenum, and a pair of cooling columns in communication with a lower plenum. A heater is located between the lower plenum and the upper plenum, wherein air is heated by the heater as air in the lower plenum is pulled through the heater and into the upper plenum. As the grain flows into the cooling column, it is exposed to cooling air being pulled through the cooling column into the lower plenum. Ductwork adjacent each heating column includes vertical sections arranged along a length of the grain dryer. Each vertical section has a fan located adjacent the uppermost horizontal level of the heating column. Each fan takes a suction from the ductwork to draw heated air from the upper plenum through the heating column.

Grain flow paths have an upper portion which is a mixed flow portion and which includes a preheat zone and a lower portion which is an undulating moisture equalizer portion and which includes a heat zone. Mixed flow grain diverters extend across the grain flow path substantially perpendicular to longitudinal side walls, and substantially parallel to transverse end walls of the grain flow path. Upper airflow openings are associated with each of the upper diverters. Moisture equalizer lower grain diverters extend along the longitudinal sides grain flow path substantially parallel to the longitudinal side walls, and substantially perpendicular to the transverse end walls of the grain flow path. The burner is positioned outside the airflow path to feed ambient air into the recirculating airflow path, without recirculating airflow passing through the burner.

A grain dryer having a mixed-flow heating section, a tempering transition section, and a vacuum-cooled crossflow cooling section. A fan positioned on the end of the dryer creates a negative pressure in the cooling plenum that pulls air through the grain, warming the air while cooling the grain. This warmed air is pulled through the fan and then passed through a heater to bring it to appropriate drying temperature. This air is then pushed into a heating plenum, where it passes through a mixed-flow grain column, drying the grain, and then exhausted to ambient air.

An improved mixed flow grain dryer is presented having a grain column with upper, middle and lower drying sections. The system includes a set of plenums and ducts configured to move air through the middle and lower drying sections at one or more lower temperatures, recover the air moved through the middle and lower drying sections, and move the recovered air through the upper drying section at a higher temperature. The system is configured to move grain through the upper drying section, then through the middle drying section, then through the lower drying section, while also: moving air of one or more lower temperatures through lower drying section and middle drying section, combining air moved through lower drying section and middle drying section, and moving the combined air through the upper drying section at a higher temperature.

A grain dryer has a heated drying section with an upper plenum and a cooling section. A heater is positioned between the lower plenum and the upper plenum, wherein air is heated by the heater as air in the lower plenum is pulled through the heater and into the upper plenum. A fan takes a suction from a ductwork on the heated drying section to draw a vacuum in the upper and lower plenums. Grain enters the dryer and flows into the drying section where the grain is exposed to heated air being pulled from the upper plenum into the ductwork. Grain flows from the drying section into the cooling section where the grain is exposed to cooling air being pulled through outer walls of the cooling section into the lower plenum. Grain flows from the cooling section into the unloading section.

A grain dryer has a heated drying section with an upper plenum and a cooling section. A heater is positioned between the lower plenum and the upper plenum, wherein air is heated by the heater as air in the lower plenum is pulled through the heater and into the upper plenum. A fan takes a suction from a ductwork on the heated drying section to draw a vacuum in the upper and lower plenums. Grain enters the dryer and flows into the drying section where the grain is exposed to heated air being pulled from the upper plenum into the ductwork. Grain flows from the drying section into the cooling section where the grain is exposed to cooling air being pulled through outer walls of the cooling section into the lower plenum. Grain flows from the cooling section into the unloading section.

An improved grain dryer is presented having a mixed-flow heating section having a plurality of inlet ducts connected to the plenum that facilitate air flow into the grain column from the heated and pressurized heat plenum, and a plurality of exhaust ducts connected to openings in the exterior wall that facilitate air flow out of the grain column. A tempering section is positioned below the heating section and includes solid walls that reduce air flow through the grain column. A cooling section is positioned below the tempering section and includes perforated walls that facilitate air flow through the grain column and into the plenum. In use, heated air is forced outward through the mixed-flow heating section heating and drying the grain and air is pulled through the cross-flow cooling section cooling the grain. Air pulled through the cross-flow cooling section is recycled into the mixed-flow heating section thereby recycling heat.

Method and apparatus for drying granular resin material by drawing vacuum over heating resin material in a vessel, while periodically purging the vessel with the material therein with dry air and bathing the vacuum dried material with dry air until furnished to a processing machine.

Method and apparatus for drying granular resin material by drawing vacuum over heating resin material in a vessel, while periodically purging the vessel with the material therein with dry air and bathing the vacuum dried material with dry air until furnished to a processing machine.

Method and apparatus for drying granular resin material by drawing vacuum over heating resin material in a vessel, while periodically purging the vessel with the material therein with dry air and bathing the vacuum dried material with dry air until furnished to a processing machine.