A blower assembly (10) includes a motor cover (18) having a body portion (40) defining a motor cavity (19), an air flow guide surface (42) connected to an end (41) of the body portion (40), the guide surface (42) extending radially outwardly from the body portion (40), and a cooling duct (44) integrally formed with the body portion (40) and having an inlet (48) and an outlet (50), the inlet (48) being located at the end (41) of the body portion and the outlet (50) being defined in a sidewall of the body portion (40). The blower assembly (10) further includes a motor (16) positionable in the motor cavity (19) the motor (16) having a motor shaft (20) having a central axis (A1). In addition, the blower assembly (10) includes a fan housing (12) connected to the motor cover (18), wherein the fan housing (12) defines a scroll cut-off line (63), and a plane (P1) passes through the scroll cut-off line (63) and the central axis (A1), and the cooling duct (44) is positioned adjacent to the plane (P1). The blower assembly (10) also includes a fan (14) positioned within the fan housing (12), wherein the fan (14) rotates in a rotational direction (65), and the cooling duct (44) is positioned on the upstream side of the plane (P1) relative to the rotational direction (65) of the fan (14).

Blower assembly having integral air flow cooling duct

A centrifugal blower is provided with a casing which defines a spiral duct and a centrifugal fan which is rotationally provided within the casing. The centrifugal fan has a bottom plate and a plurality of blades which are equally spaced along the periphery of the bottom plate. The plurality of blades extends parallel to the rotational axis. The duct is arranged to reduce the size of a low velocity air flow zone which is generated in an upper radially outer region in the spiral duct. The low velocity air flow zone, which appears in an upper radially outer region in the air duct, is reduced to reduce surging in the blower.

Centrifugal blower improved to reduce vibration and noise

A fan assembly has a base portion that remains stationary during the operation of the fan assembly, the base portion having a stationary base support plate. The assembly also includes a blower portion that includes an oscillating top plate, a blower that is coupled to the top plate and which oscillates when the top plate oscillates, and a grill cover that is coupled to the base support plate so that the grill cover remains stationary even when the top plate and the blower oscillates. The assembly can optionally include a smooth glide mechanism positioned between the top plate and the base support plate.

Tower fan assembly

A bell-mouth ring is formed with a casing to be disposed proximately at an outer radial side of a shroud. The bell-mouth ring has a deflection wall surface for deflecting a flow of air blown out radially outwardly from the centrifugal multi-blade fan and further flowing radially inwardly toward the rotation axis along an inner wall surface of the casing, toward the driving means. In this way, it is possible to suppress air from flowing backward to a suction port through a gap between the shroud and the bell-mouth ring. Accordingly, it is possible to reduce the noise generated by an interference of the air sucked from the suction port with the air flowing backward or by the turbulence of the air flow which is generated in the gap.

Centrifugal blower having a bell-mouth ring for reducing noise

In a predetermined range from a nose portion toward a scroll finish side in a scroll casing of a centrifugal blower, a first clearance dimension on a side of a suction port between an outer periphery of a centrifugal fan and a side plate of the scroll casing is set smaller than a second clearance dimension on a side opposite to the suction port between the outer periphery of the centrifugal fan and the side plate of the scroll casing In addition, in the vicinity of the nose portion, a first wall part of the scroll casing on the side of the suction port protrudes toward a scroll finish side, from a second wall part of the scroll casing on the side opposite to the suction port

Centrifugal blower having noise-reduction structure

A multi-blade fan having a fan assembly including a bottom plate and a plurality of circumferentially spaced blades and a casing for the fan assembly therein having an outlet duct extending therefrom for discharge of the air flows. The fan assembly includes an annular shroud connected to the axial ends of the blades remote from the bottom plate. The casing includes a bottom wall for rotatably connecting the fan assembly, a top wall for defining an air inlet for axially introducing the air into the casing, and a tubular wall connecting the bottom and top walls. The top wall of the casing adjacent to the inlet opening forms an annular projection having a bell cross sectional shape opened inwardly so that an axial end of the shroud extends thereto. The bell cross section portion radially extends to a portion that is inclined downwardly in the outward direction, which faces the shroud so that a small gap extending radially is created. The top wall or bottom wall of the casing at its radially outer portion can be downwardly inclined. The tubular wall of the casing can also be inclined so that the bottom end of the tubular wall is flared radially outward from its center.

Multi-blades fan device

A multi-blade blower with a reduced operating noise. The blower has a casing 3, inside of which a noise generator of a circular cross sectional shape is arranged at a position adjacent a throat of the scroll passageway. The noise generator has a radial gap S with respect to the outer edge of blade which is the same as a radial gap of the throat with the outer edge of the blade, and the spacing between the throat and the noise generator in the direction of the rotation of the wheel is 1.5 times of the blade pitch of the wheel.

Yasushi Kondo

Papers

Multi-blades fan device

Centrifugal blower improved to reduce vibration and noise

Multi-blade blower