Provided is a centrifugal fan. The centrifugal fan includes an air inlet, a shaft, and a plurality of blades. The blades are arranged around the shaft. Each of the blades includes an air guiding portion on a side of the blade facing the air inlet. The air guiding portion includes a first curve and a second curve. An air inflow channel is formed between the first curve and the second curve of two adjacent air guiding portions respectively. A width of the air inflow channel is expanded in a direction away from the air inlet according to an expanding ratio.

Provided is a centrifugal fan. The centrifugal fan includes an air inlet, a shaft, and a plurality of blades. The blades are arranged around the shaft. Each of the blades includes an air guiding portion on a side of the blade facing the air inlet. The air guiding portion includes a first curve and a second curve. An air inflow channel is formed between the first curve and the second curve of two adjacent air guiding portions respectively. A width of the air inflow channel is expanded in a direction away from the air inlet according to an expanding ratio.

A dual stage blower assembly includes a first fan configured to rotate about the rotational axis and including a first plurality blades. The first plurality of blades include a plurality of backward curved blades. The dual stage blower assembly also includes a second fan circumscribing the first fan and configured to rotate about the rotational axis. The second fan includes a second plurality of blades, wherein the second plurality of blades include one of a plurality of forward curved blades, a plurality of a radial blades, or a plurality of backward curved blades. At least one motor is coupled to the first fan and the second fan and configured to rotate the first fan and the second fan about the rotational axis.

A dual stage blower assembly includes a first fan configured to rotate about the rotational axis and including a first plurality blades. The first plurality of blades include a plurality of backward curved blades. The dual stage blower assembly also includes a second fan circumscribing the first fan and configured to rotate about the rotational axis. The second fan includes a second plurality of blades, wherein the second plurality of blades include one of a plurality of forward curved blades, a plurality of a radial blades, or a plurality of backward curved blades. At least one motor is coupled to the first fan and the second fan and configured to rotate the first fan and the second fan about the rotational axis.

A method for creating an impeller and an impeller of a radial turbo fluid energy machine includes a wheel disc, cover disc, blades, and hub. The hub is mounted on a shaft which extends along an axis, the wheel disc extends substantially radially from the hub, and the cover disc is connected to the wheel disc by the blades such that flow channels separated from one another in the circumferential direction are defined by the blades. The impeller has a first flow passage in a substantially axial direction in the radial proximity of the hub, and the impeller has a second flow passage in a substantially radial direction radially farther away from the hub than the first flow path passage. The cover disc surface facing the wheel disc has a lower degree of roughness at least in some regions than the wheel disc surface facing the cover disc.

A method for creating an impeller and an impeller of a radial turbo fluid energy machine includes a wheel disc, cover disc, blades, and hub. The hub is mounted on a shaft which extends along an axis, the wheel disc extends substantially radially from the hub, and the cover disc is connected to the wheel disc by the blades such that flow channels separated from one another in the circumferential direction are defined by the blades. The impeller has a first flow passage in a substantially axial direction in the radial proximity of the hub, and the impeller has a second flow passage in a substantially radial direction radially farther away from the hub than the first flow path passage. The cover disc surface facing the wheel disc has a lower degree of roughness at least in some regions than the wheel disc surface facing the cover disc.

A centrifugal compressor having a stator which is designed as an inlet stator, in particular for a compressor, with at least one vane having a vane airfoil around which a fluid can flow, with a plurality of vanes arranged in the form of a ring, with an adjustment device for adjusting the vane, wherein a curvature of a profile center line of the vane airfoil has at least one inflection point.

A centrifugal compressor having a stator which is designed as an inlet stator, in particular for a compressor, with at least one vane having a vane airfoil around which a fluid can flow, with a plurality of vanes arranged in the form of a ring, with an adjustment device for adjusting the vane, wherein a curvature of a profile center line of the vane airfoil has at least one inflection point.

A profiled blade for a fan impeller comprising a profiled body produced from at least one bent sheet metal strip. The profiled body includes a profile top part with a convex curvature, a profile bottom part located at a distance from the profile top part, and first and second profile noses. Each of the profile noses has a convex curvature and joins the profile top part to the profile bottom part at ends of the profiled body. The profile top part and/or the profile bottom part is divided into at least first and second profile sections. The first profile section is joined to the first profile nose and the second profile section is joined to the second profile nose. A first free end region of the first profile section is joined to a second free end region of the second profile section by adhesive force.

A profiled blade for a fan impeller comprising a profiled body produced from at least one bent sheet metal strip. The profiled body includes a profile top part with a convex curvature, a profile bottom part located at a distance from the profile top part, and first and second profile noses. Each of the profile noses has a convex curvature and joins the profile top part to the profile bottom part at ends of the profiled body. The profile top part and/or the profile bottom part is divided into at least first and second profile sections. The first profile section is joined to the first profile nose and the second profile section is joined to the second profile nose. A first free end region of the first profile section is joined to a second free end region of the second profile section by adhesive force.