In this application, continuous drying of materials is being performed by exposure to the heated surfaces of rotating cylinders or drums. Commonly used in the manufacture of felt, rubber, textiles, paper and other sheet or fibrous materials, including foods and slurries of chemicals. Higher start-up loads and moderate running loads are typical. When several dryers are in series, the first will have the highest load while those toward the end have progressively smaller loads. Each dryer should be trapped individually to prevent flooding.
Syphon drainage is standard practice.
Condensate moving up the syphon from the outer rim to the center of the drum is subject to reheating and flashing. Therefore, steam traps must have hot discharge and fast response with the ability to handle flash steam by means of a small bleed passage. Air venting capability is an important requirement during start-up when drums or cylinders contain large amounts of air. Thermodynamic traps are phase detectors in that they can discriminate between condensate and steam. The working principle is simple and, with only one moving part, these devices are small and rugged.