Structure for reducing noise of ventilating fan

摘要

Disclosed is a structure for reducing noise of a ventilating fan. The structure includes an orifice plate fixed on a scroll casing and is shaped to be an annular and semi-surrounding hollow structure in order to match with the shape of an air inlet of the scroll casing, and to cover only the air inlet of the scroll casing. The noise generated by an air blower of the ventilating fan can be directed along a bell mouth of the scroll casing of the ventilating fan after being emitted from the air inlet of the scroll casing, and then can be smoothly sucked by the orifice plate. The sucked-in noise can repeatedly collide with the orifice plate and be diffused, thereby the energy being gradually weakened and the sound pressure thereof being decreased.

主权项

1. A structure for reducing noise of a ventilating fan, comprising:
a bell-mouthed panel located at an air inlet of a scroll casing; and an orifice plate fixed on the scroll casing; wherein the orifice plate is shaped to be an annular and semi-surrounding hollow structure in order to match with a shape of the bell-mouthed panel, and covers only a front side of the air inlet of the scroll casing, the orifice plate comprises a radially outward side with respect to a longitudinal axis of the air inlet, a radially inward side, and a middle part in the form of a hollow structure that is disposed between the radially outward side and the radially inward side, wherein the radially outward side extends linearly from a surface in which the air inlet of the scroll casing is located, and the radially inward side extends from the radially outward side toward the air inlet, the radially outward side has a cylindrical shape which extends from the scroll casing in an axial direction parallel to the longitudinal axis of the air inlet, and faces a housing side of the ventilating fan, and the radially inward side has a curved shape and includes a fixed end extending from the radially outward side and a free end which arcs inwardly toward the longitudinal axis of the air inlet, the free end terminating at a location radially outside of the air inlet of the scroll casing.