Abstract: An HVAC unit ventilator, particularly suited for schools and hotels, includes a single damper blade driven directly by a motor to control a supply air's mixture of return air and outside air. The damper blade is selectively pivotal to a full outside air position, a full return air position, and various intermediate mixed-air positions. The damper blade has flexible edge and end seals that create little if any frictional drag as the damper blade pivots to the intermediate positions, yet the seals provide a positive, tight seal when the damper stops at either the full outside air position or the full return air position. The unit ventilator includes a filter frame that not only supports an air filter but also provides the damper blade with sealing surfaces and structural support. For rigidity, the damper blade has somewhat of a box-like structure that is bi-directionally reinforced by ribs and triangular gussets.

Abstract: An HVAC unit ventilator, particularly suited for schools and hotels, includes a single damper blade driven directly by a motor to control a supply air's mixture of return air and outside air. The damper blade is selectively pivotal to a full outside air position, a full return air position, and various intermediate mixed-air positions. The damper blade has flexible edge and end seals that create little if any frictional drag as the damper blade pivots to the intermediate positions, yet the seals provide a positive, tight seal when the damper stops at either the full outside air position or the full return air position. The unit ventilator includes a filter frame that not only supports an air filter but also provides the damper blade with sealing surfaces and structural support. For rigidity, the damper blade has somewhat of a box-like structure that is bi-directionally reinforced by ribs and triangular gussets.