In Counterflow Dryers the grain and air flow are in opposite directions. Typically a round bin is used that has a perforated floor and a sweep auger. Heated air is pushed up through the grain while the sweep auger removes grain as the control system indicates the grain has reached the desired moisture. Hot grain is moved to a cooling bin when it is discharged from the dryer. One advantage of this dryer type is that wet grain can be piled on top of the drying grain, eliminating the need for a separate wet holding bin. Fines can affect airflow from the perforated floor so it is recommended that the grain be screened before drying and it is usually necessary to shut down the dryer every 3-4 days to remove fines from the floor to maintain proper air flow. These are one of the more efficient continuous flow type dryers being about 40% more efficient than a cross-flow dryer with out heat recovery. This type of dryer can be retrofitted to an existing bin, reducing the initial dryer cost and can be used to store grain by drying the last grain operating the dryer in a re-circulating batch dryer mode.
The Counterflow Dryers have the following advantages:
The Counterflow Dryers stand out because of their superior energy efficiency when compared to any alternative dryer. Compared to the best horizontal dryers, it can guarantee an energy consumption that is typically at least 15% lower. When replacing older horizontal dryers, savings on energy can be up to 50%.
The use of gravity flow allows to engineer Dryers and coolers with a minimum of moving parts and without any wear parts. Moreover, lack of maintenance that is required for a counterflow cooler. The Counterflow Dryers are no different.
Moisture uniformity and control play an important role in the profitability of the any dryer operator. The Counterflow Dryers can achieve the same moisture uniformity as the best horizontal dryers. Improvements over older dryers lead to high savings in product and energy costs.
The use of gravity for product transport ensures an uninterrupted product flow, leading to a large reduction in cleaning frequency and cleaning costs, whilst maintaining the highest possible standards of sanitation.