Abstract: A fan with a housing which defines an axial flow channel having a cross-section, wherein the flow channel has a first axial portion on the suction side and a second axial portion adjoining in the flow direction. The flow channel has a first cross-section in the first axial portion a transitioning cross-section through the second axial portion. The cross-section is arranged concentrically in an imaginary rectangular base area, the side edges of which coincide at least in sections with a contour of the first cross-section, and wherein the flow channel has in its second axial portion an intermediate cross-section which widens in the flow direction within the base area and which, starting from the first cross-section, increases to a second cross-section at the pressure-side end of the second axial portion.

Abstract: An impeller with impeller blades arranged around a rotational axis of the impeller. Integral, seamless, and notch-free transitions are formed into a disc body on at least one of their two axial sides. The disc body connects the impeller blades in the circumferential direction around the rotational axis. Covering portions, between the impeller blades, determine the flow channels of the impeller.

Abstract: An impeller with impeller blades arranged around a rotational axis of the impeller. Integral, seamless, and notch-free transitions are formed into a disc body on at least one of their two axial sides. The disc body connects the impeller blades in the circumferential direction around the rotational axis. Covering portions, between the impeller blades, determine the flow channels of the impeller.