| 摘要 |
A damper unit for ventilating systems and comprising a housing having two internal ducts or passages for fresh air and return air, respectively, and an internal by-pass between the ducts. The ducts are parallel at the outer end of the housing and concentric at the inner end thereof. One of the internal ducts is defined by an inclined, tubular partition wall which at its outer end merges with the housing wall and with a central partition between the parallel outer duct ends. A pivotal damper has a first end position in which it obturates the by-pass which is provided in the central partition, and a second end position in which it obturates the outer ends of both ducts and opens the by-pass to provide full recirculation of spent room air. In intermediate positions the damper provides for partial recirculation. |
