The present invention relates to a centrifugal fan comprising a fan housing with a radial outlet opening arranged in a radial peripheral wall thereof, a rotor arranged rotatably in the fan housing and provided close to an axial rotation axis thereof with a rotor inflow opening, wherein the fan housing is provided close to the rotation axis of the rotor with an axial inlet opening, and a tube part which extends in the fan housing from the radial outlet opening arranged in the radial peripheral wall and inward along the radial peripheral wall. The invention further relates to a heating device comprising a burner with a fuel mixture infeed opening, a centrifugal fan according to the invention, and wherein a fluid connection is provided between the fuel mixture infeed opening of the burner and the outlet opening of the centrifugal fan.

A blower includes a moving blade, a motor, and a housing. The housing includes a holding portion located below the moving blade to hold the motor, and a peripheral wall portion having a cylindrical shape centered on the central axis and extending upward from a radially outer end portion of the holding portion. The peripheral wall portion includes a peripheral wall recess that is recessed downward from an upper end portion of the peripheral wall portion and connects a space radially inside of the peripheral wall portion and a space radially outside of the peripheral wall portion, and includes a first peripheral surface facing one circumferential direction that is opposite to a rotation direction of the moving blade. The first peripheral surface extends in one circumferential direction from the upper end of the peripheral wall recess toward the lower side.

A blower includes a rotor blade rotatable about a central axis extending in an axial direction, a motor that rotates the rotor blade, and a housing that surrounds the rotor blade and the motor. The housing includes stator blades extending in a forward rotation direction of the rotor blade toward an axially lower side of the blower, a porous wall including multiple holes arranged in both the radial direction and in the circumferential direction, and a cylinder portion extending in the axial direction and radially outward of the porous wall. The hole penetrates the porous wall through upper to lower surfaces thereof. The stator blade is axially below the rotor blade. An axially upper end portion of the porous wall is between an axially lower end portion of the rotor blade and an axially upper end portion of the stator blade.

A blower for providing a supply of air at positive pressure in the range of approximately 2 cmH.sub.2O to 30 cmH.sub.2O includes a motor, at least one impeller, and a stationary component. The stationary component includes an inlet and an outlet. The motor, the impeller, the inlet and outlet are co-axial.

Embodiments of the present disclosure are directed to an inline centrifugal mixed flow fan system that includes a wheel assembly disposed within an outer housing and comprising a hub cone, a plurality of fan blades directly coupled to and extending radially outward from the hub cone, and a shroud directly coupled to and at least partially radially surrounding the plurality of fan blades. The wheel assembly is configured to receive an air flow at an inlet axial end of the outer housing axially upstream of the wheel assembly, and to redirect the air flow axially downstream relative to a central longitudinal axis, circumferentially about the central longitudinal axis, and radially outward from the central longitudinal axis.

The present invention relates to an air cleaner, including a body forming an exterior; a suction portion formed on the body to suck air; a discharge portion formed on the body and discharging the air sucked through the suction portion; and a fan module provided in the body to form a flow of air flowing from the suction portion to the discharge portion, wherein the fan module includes: a driving portion forming a rotation shaft and generating power; a fan receiving the power from the driving portion and rotating about the rotation shaft; and a shroud accommodating the fan and provided between the suction portion and the discharge portion to guide the air sucked through the suction portion to the discharge portion, and the shroud includes a guide portion guiding foreign substances introduced through the discharge portion in a direction opposite to the flow of air.

A fan device includes an impeller rotating around a central axis and a motor disposed farther downward than the impeller. The impeller includes a base unit enlarged downward and plural blades disposed on a peripheral surface of the base unit. Upper portions of the blades are positioned at a leading end of a rotating direction with respect to lower portions. In an outer end portion on a front surface of each blade at the leading end of the rotating direction, a radial-direction component of a normal unit vector of an upper end portion of the blade is smaller than that of a lower end portion, assuming that an outer peripheral side of the blade is a positive direction. A thickness of a root of the lower end portion is larger than that of the upper end portion.

A blower for providing a supply of air at positive pressure in the range of approximately 2 cm H2O to 30 cm H2O includes a motor, at least one impeller, and a stationary component. The stationary component includes an inlet and an outlet. The motor, the impeller, the inlet and outlet are co-axial.

An impeller includes a disk-shaped portion and rotor blades. The rotor blades include first rotor blades which includes a first curvature portion and second curvature portions. A center of a radius of curvature of the first curvature portion is on a first side. A center of a radius of curvature of each second curvature portion is on a second side. The radius of curvature of the second curvature portion radially outward is greater than the radius of curvature of the second curvature portion radially inward. The rotor blades include second rotor blades each of which is circumferentially between adjacent ones of the first rotor blades. Each second rotor blade includes third curvature portions. A center of a radius of curvature is on the second side. The radius of curvature of the third curvature portion radially outward is greater than the radius of curvature of the third curvature portion radially inward.

A first bearing box has, in one end face perpendicular to a direction along a rotor shaft and farther from a fan, an air outlet for air taken in through an air inlet to exit. A flow channel is defined between an outer peripheral surface of a cylindrical portion of the first bearing box continuous with the end face and a frame. A value obtained by dividing a distance between an outer periphery of blades in the fan and the air outlet by an outer radius of the blades is greater than or equal to a threshold.