Abstract: The invention relates to a single pass airflow apparatus for cooling and drying corrugated product having open flutes, comprising an airflow exhaust duct having a first cross-sectional area, an inlet plenum with a cross-section area greater than the airflow exhaust duct and having an exit in airflow communication with an inlet to the airflow exhaust duct. The plenum has an open faced chamber abuttingly facing the stack of corrugated product which presents the open flutes to the plenum. A fan is provided for drawing airflow through corrugated product into the plenum and from there into airflow exhaust duct from whence the drawn air is exhausted to atmosphere. The invention is directed to the structure and to the method of its use.