| 摘要 |
A closed loop oxygen reduced gas recirculation system for an industrial dryer includes high volume primary and low volume secondary gas recirculation paths with a condenser apparatus in the secondary path for removing water and solvent. A natural gas burner produces both oxygen reduced gas for the system and the required energy for the dryer. An optional condenser apparatus removes water vapor from the oxygen reduced gas output of the burner prior to its reaching the dryer. The condenser apparatus may include a first heat exchanger and a pair of parallel alternately operating downstream output heat exchangers, such as refrigeration coils. The first heat exchanger condenses most of the water vapor from the dryer gas and vaporized solvent is condensed in one of the output heat exchangers while the other is being defrosted. Sensors detect frost buildup in the operating output heat exchanger and actuate an automatic defrost control which causes dampers to switch and direct exhaust gas to the previously nonoperating output heat exchanger while the previously operating heat exchanger is defrosted, as by a hot defrost gas. Also, the heat exchangers may be of the counterflow type connected such that the cooled exhaust gas is fed back through the heat exchangers in reverse order to act as the cooling fluid. A defrost fluid may be delivered to the nonoperating heat exchanger during defrosting. |
