Centrifugal ventilator e.g. reaction ventilator, for conveying air in ventilation system of building, has projections projected toward outside for ensuring clearance between wheel and interior faces of anterior and posterior walls

摘要

The ventilator (1) has a volute casing (22) formed by anterior walls (24) and posterior walls (26), whose respective edges are connected by a lateral wall (30). The anterior and posterior walls include interior faces (34, 36) arranged in one of a set of zones of the casing. One of the anterior and posterior walls has projections (40, 42) arranged in the other zone of the casing, where the projections are projected toward outside for ensuring a clearance between a wheel (2) and the interior faces of the anterior and posterior walls in axial and radial directions.