Shut-off flap and corresponding heating, ventilation and/or air conditioning installation

A heating, ventilation and/or air conditioning installation, comprising:

• at least one shut-off flap having a rotation axle, a first face and a second face opposite to the first face, said first and second faces of the shut-off flap defining a plane, said shut-off flap comprising:
• a rotation shaft projecting on each face of the plane defined by the first and second faces of the shut-off flap;
• and
• at least one lateral wall having a planar surface of substantially parallelepipedal,
• wherein the first face has at least one first row of blind orifices and the second face of the shut-off flap has at least one second row of blind orifices, said first and second rows of blind orifices being positioned at the level of the rotation shaft parallel to the rotation axle of the shut-off flap, said second row of blind orifices being positioned offset from the rotation axle
• wherein the first and second rows of blind orifices are arranged in alternation on the first face and on the second face of the shut-off flap, and
• wherein the rotation shaft also has at least two longitudinal ribs including a first rib positioned substantially at a center of the first row of blind orifices and parallel to a longitudinal direction of the rotation shaft, and a second rib positioned substantially at a center of the second row of blind orifices parallel to the longitudinal direction of the rotation shaft such that the second rib is offset from the rotation axle.