VENTILATING SYSTEM FOR DRYERS

摘要

First and second ported ducts are associated with a drying chamber. A flow control housing has first and second compartments communicating respectively with the first and second ducts. These compartments also have openings which communicate with atmosphere. A fan is employed which draws air from the drying chamber into one of the ducts and through one of the compartments to atmosphere. At the same time a fan on a common shaft draws in make-up air from the atmosphere and forces it through the other of the compartments and into the other duct for discharge into the dryer. The fans are reversible, and the flow control housing is combined with a double acting heat exchanger which extracts heat from exhaust air in one compartment and transfers it to the other compartment for preheating make-up air. A damper is provided in the flow control housing on the atmosphere side thereof for precise control of exhaust and make-up air.