In 1976, Crown became the first and only United States company to obtain a license from Heinz Schumacher for the Desolventizer-Toaster-Dryer-Cooler (DTDC). Crown has continually modified and improved the design, offering the most efficient DTDC built. Today, it is known as the Crown/Schumacher design.
After all the oil has been removed from the oilseed flakes or cake, they leave the Crown Extractor with approximately 30% solvent (hexane) content. The Crown/Schumacher Desolventizer-Toaster (DT) is the newest innovation in removing the hexane from the flakes and completing the toasting operation.
From the DT, the flakes are either conveyed to a Dryer-Cooler (DC) or, in the case of a Crown DTDC, they pass through the rotary valve, directly into the drying section of the DC. The drying and cooling are accomplished by blowing heated air in the drying section (dryer trays) and using ambient air to cool the meal in the cooling section (cooling tray).
- Efficient, robust, reliable and simple to operate
- Significantly lower steam usage and distinctly lower solvent losses
- More stable meal temperatures in all lower trays allow a greater degree of safety. A drop in meal temperature in the top tray due to operation errors can also be recovered more easily in the second or succeeding trays
- The predesolventizing by the steam-heated trays reduces the amount of sparge steam required and also reduces the meal moisture proportionally, thereby reducing the steam usage in the meal dryer
- Automatic level control with actuated gates, chutes or variable rotary valves means less operator attention required
- Unique counter-current flow
- Low horsepower-per-ton requirements
- Heavy-duty steam chests and robust computer-designed sweep arms
- Basket-type predesolventizing trays
- Large dome of DT for reduced dust carried out with vapors
- Patented Vapor Recovery System for even less steam use and lower solvent consumption