A ventilation device includes a fan including a hub coupled to a rotating shaft, a plurality of blades disposed at the hub and disposed radially with respect to the rotating shaft, and a shroud connecting the plurality of blades. The ventilation device further includes a scroll guide configured to guide a cold air discharged from the fan in both directions, and first and second ducts extending from the scroll guide and extending along a rotation direction of the fan. In the first and second ducts, a length of a hub-side surface is greater than a length of a shroud-side surface.

A centrifugal air blower comprises a fan; and a scroll casing. The scroll casing includes: a sidewall covering the fan from an axial direction of a rotation axis on which the fan rotates, the side wall having a suction opening for sucking air; a discharge opening for discharging an airflow generated by the fan; a tongue portion for guiding the airflow to the discharge opening; a peripheral wall surrounding the fan from a radial direction of the rotation axis; and a bell mouth formed along the suction opening of the sidewall. The bell mouth includes an upstream end and a downstream end, the upstream end being an end portion on an upstream side in a direction of flow of the air passing through the suction opening, the downstream end being an end portion on a downstream side in the direction of flow of the air.

A centrifugal air blower comprises a fan (2); and a scroll casing (4). The scroll casing includes: a sidewall (4c) covering the fan (2) from an axial direction of a rotation axis on which the fan (2) rotates, the side wall having a suction opening for sucking air; a discharge opening (41) for discharging an airflow generated by the fan (2); a tongue portion (4b) for guiding the airflow to the discharge opening (41); a peripheral wall (4a) surrounding the fan (2) from a radial direction of the rotation axis; and a bell mouth (3) formed along the suction opening (5) of the sidewall (4c). The bell mouth (3) includes an upstream end (3a) and a downstream end (3b), the upstream end being an end portion on an upstream side in a direction of flow of the air passing through the suction opening (5), the downstream end being an end portion on a downstream side in the direction of flow of the air. A distance in the radial direction of the rotation shaft between the upstream end (3a) and the downstream end (3b) at a location larger than the tongue portion (4b) in angle of a direction of rotation of the fan (2) is longer than a distance in the radial direction between the upstream end (3a) and the downstream (3b) end at a location adjacent to the tongue portion (4b).

A centrifugal fan and a clothing dryer. The centrifugal fan includes a housing as well as an impeller and a worm tongue disposed in the housing. The housing has an air inlet and an air outlet. The volute tongue includes a first volute tongue and a second volute tongue that are stacked and staggered. The first volute tongue cuts the air blown from the impeller and guide the air to the air outlet when the impeller rotates forward. The second volute tongue cuts the air blown from the impeller and guide the air to the air outlet when the impeller rotates backward. When the impeller rotates, the first volute tongue or the second volute tongue can cut the air blown from the impeller and guide the air to the air outlet, so that the centrifugal fan can blow out air when the impeller rotates forward and backward.

A blower assembly for a heating, ventilation, and/or air conditioning (HVAC) system includes a centrifugal fan having a fan wheel. A plurality of blades are coupled to the fan wheel at an inner blade boundary and extend radially to an outer blade boundary. The blower assembly includes a first housing panel and a second housing panel disposed on opposite sides of the centrifugal fan and extending transverse to the centrifugal fan. The blower assembly includes a wall extending between the first housing panel and the second housing panel and a flange extending from the wall at a vertex. The flange extends outwardly from the wall. A first radial distance from the vertex to the outer blade boundary is between 4 percent and 20 percent of a second radial distance from a rotational axis of the centrifugal fan to the outer blade boundary.

An air-conditioning apparatus includes: a centrifugal air-sending device including a fan and a scroll casing having a tongue portion and a discharge portion, and a housing having a housing suction port and a discharge portion. A trailing edge of a blade located closest to a wall portion of the housing is a first trailing edge portion, and a leading edge of a blade located closest to the tongue portion is a first leading edge portion. In a first region, a boundary portion located closest to the tongue portion is located between first and second straight lines. The first straight line passes through a rotation axis of the fan and the first trailing edge portion, the second straight line is parallel to the first straight line and passes through the first leading edge portion, and the first region forms part of the housing suction port close to the tongue portion.

A supercharging device is configured to increase an amount of intake air of an engine of a vehicle, where the supercharging device includes a chamber formed to be open in an ejecting direction of a compressor outside an ejecting portion of a compressor housing of the compressor, and an air adding device configured to supply air not compressed by the compressor to the chamber.

A blower for an HVAC system, the blower includes a housing with an intake and an outlet, a fan or blower wheel disposed within the housing and configured to draw air into the housing via the intake and to exhaust air from the housing through the outlet, and an adjustable cutoff plate configured to be moved between at least a first position defining a first cutoff angle and a second position defining a second cutoff angle.

A fan with an impeller having, in an embodiment, backward-curved blades and having a scroll housing, the flow channel of which is formed by an inner spiral contour of the housing, the flow channel guiding the air conveyed by the impeller towards an outlet wherein the spiral contour with its local pitch angles is adapted to the outlet angle from the impeller.

Provided is a cooling fan including: a fan housing having an air inlet formed on a front surface thereof and through which air flows and an air outlet formed at a side surface of the fan housing and through which air is discharged; and an impeller mounted inside the fan housing to introduce air in an axial direction thereof and discharge air in a radial direction thereof, wherein a bypass passage is formed at an edge of the air inlet so that air flowing in a direction opposite to the air outlet can be discharged to the outside. At high power of a cooling fan, backward-flow air is discharged to the outside to minimize noise and improve blowing efficiency.