A multistage turbomachine is disclosed, comprising a casing with a fluid inlet and a fluid outlet and a plurality of stages arranged in the casing. A flow path extends from the fluid inlet to the fluid outlet through the sequentially arranged stages. Each stage is comprised of a rotating impeller and an electric motor embedded in the casing and arranged for rotating the impeller at a controlled rotary speed. Each electric motor comprises a motor rotor, arranged on the impeller and integrally rotating therewith, and a motor stator stationarily arranged in the casing. Pairs of sequentially arranged impellers are configured for rotation in opposite directions.

An air-moving device having a first fan system and a second fan system that are configured relative to each other to create a flow of air. The air-moving device may be a leaf blower.

An air-moving device may include an aerodynamic rotor in the form of a bladed disk. The aerodynamic rotor may include a physical geometry that constrains a noise level of the air-moving device.

An air-moving device may include an aerodynamic rotor in the form of a bladed disk. The aerodynamic rotor may include a physical geometry that constrains a noise level of the air-moving device during operation. The air-moving device may be a leaf blower.

A recirculation fan includes a casing, a covering member, a wind-guiding device, a passive impeller, and an active impeller. The covering member is coupled with the casing to define an accommodation space. The wind-guiding device is disposed on the covering member, and includes a wind-guiding cover and a magnetoresistive structure. The magnetoresistive structure is disposed on the covering member and the wind-guiding cover. The passive impeller is disposed within the accommodation space. The active impeller is disposed within the accommodation space and located beside the passive impeller for generating a wind to drive rotation of the passive impeller and the wind-guiding cover. In response to a magnetic torque resulted from a magnetic vortex of the magnetoresistive structure, a rotating speed of the wind-guiding cover is slowed down.

A compressor or pump stage is provided. The compressor or pump stage at least comprising a central shaft and at least one rotor, wherein an axis of rotation of the at least one rotor is the central shaft, wherein at least two axial thrust bearings are arranged axially remote from each other and being associated with each of the at least one rotor and at least two radial bearings arranged between the at least two axial thrust bearings and the at least one rotor comprises a number, n, of rows of impellers arranged at an outer perimeter of the at least one rotor with an axial distance between neighbouring rows of impellers, where n={2, 3, 4 . . . }

A flow control device for constraining fluid flow between axial flow turbomachines in series has a flow constrainer which constrains the fluid flow downstream of the first turbomachine in the series to the blades region of the second turbomachine, preventing fluid flow from impacting the hub or nosecone of the second turbomachine and providing more uniform fluid flow to the second turbomachine. The flow control device includes connective elements for positioning between the downstream region of the first turbomachine and the upstream region of the second turbomachine. The device may be equipped with stator vanes having a variety of optional configurations to further improve the uniformity of the fluid flow load on the second turbomachine.