In one example, a centrifugal fan includes a bearing, a shaft rotatably supported by the bearing, fan blades operatively connected to and rotatable with the shaft to take in air axially and to exhaust air radially, and a groove in the shaft extending axially along an outer surface of the shaft through the bearing.

A scroll casing of a centrifugal compressor includes a scroll part forming a scroll passage of the centrifugal compressor. The scroll part has a near-circular scroll cross-section which includes a first arc portion extending from a connection position with a hub-side passage surface of a diffuser passage of the centrifugal compressor (first position) to a one-direction side (side toward fourth position), a second arc portion formed on the one-direction side of the first arc portion so as to include at least a part of a region between an outermost end in the radial direction (second position) and an innermost end in the radial direction (fourth position), and a third arc portion formed on the one-direction side of the second arc portion so as to include an end position of the scroll part on the one-direction side (fifth position) and satisfies a relationship of R2>R3, where R2 is a curvature radius of the second arc portion, and R3 is a curvature radius of the third arc portion.

The air compressor includes: a housing assembly, wherein the housing assembly has a first installation cavity, a second installation cavity and a rotation-shaft cooperating cavity, and the first installation cavity has a gas inlet and a gas outlet; a rotor shaft, wherein the rotor shaft is rotatably fitted inside the rotation-shaft cooperating cavity, and extends into the first installation cavity and the second installation cavity; a pressure wheel, wherein the pressure wheel is nested to the rotor shaft and is located inside the first installation cavity, and the housing assembly is provided with a controlling flow channel for communicating the gas-intake side and the wheel-back side of the pressure wheel; and a driving assembly, wherein the driving assembly is nested to the rotor shaft and is located inside the second installation cavity.

Embodiments of this application provide a centrifugal pump. The centrifugal pump includes a pump casing and a first drive mechanism, a second drive mechanism, a pump shaft, and an impeller that are disposed in the pump casing. The pump casing includes a first chamber and a second chamber that are connected. An axis of the pump shaft coincides with axes of the first chamber and the second chamber. An inner diameter of the second chamber is greater than that of the first chamber. The impeller is connected to an end of the pump shaft. The first drive mechanism and the second drive mechanism are connected to the pump shaft and located on a side, away from the impeller, of the pump shaft. The first drive mechanism is configured to drive the pump shaft to rotate.

The disclosure relates to an asymmetrical double-outlet blower, including an upper case, a lower case and an impeller. The upper case includes an inlet. The lower case and the upper case are assembled to form a housing having an accommodation space, and form a first outlet and a second outlet. The accommodation space is in fluid communication with the first outlet, the second outlet and the inlet. The first outlet and the second outlet are disposed on a lateral periphery of the housing and face two opposite directions, respectively. An opening cross-sectional area of the first outlet is less than an opening cross-sectional area of the second outlet. The impeller is accommodated within the accommodation space of the housing, spatially corresponding to the inlet, and rotated around a rotation axis. An airflow is inhaled through the inlet and transported to the first outlet and the second outlet, respectively.

An electric blower includes a motor unit, a shaft, a centrifugal impeller, a fan cover, a motor unit case, and a bracket located away from centrifugal impeller and toward motor unit in a direction in which a central axis of the shaft extends. The bracket includes a first portion located outward of the vent in a radial direction, and a second portion located outward of the first portion and outward of an outer circumference of the motor unit case in the radial direction. A first airflow passage and a second airflow passage are formed in the bracket, the first and second airflow passages communicate with an airflow passage formed by the centrifugal impeller and the fan cover.

Airflow from a blower fan can be adjusted between a cooling air mode where cooling air flows freely to the ambient surroundings and a noise mode where the airflow is partially or fully restricted in order to produce different levels of soothing background noise. The airflow from the fan can be split or divided between varying degrees and combinations of unrestricted airflow, partially restricted airflow and fully restricted airflow to produce a wide range of cooling airflows into the ambient with or without the production of additional background noise. A perforated drum surrounds the fan to form a chamber within which airflow can resonate at various frequencies and amplify noise levels selected by rotating the drum around the fan.

The present invention relates to a pressure wall for a centrifugal pump for fluid having substantially the shape of a disc, the disc-shaped pressure wall having a central axis, the pressure wall comprising: a top surface; and a bottom surface opposing the top surface; wherein the top surface includes an inner surface section and an outer surface section, wherein the inner surface section extends radially from the central axis and is recessed to form a central recess; and wherein the outer surface section includes an inner circumferential edge portion and an outer circumferential edge portion, wherein the inner circumferential edge portion is located closer to the central axis than the outer circumferential edge portion, and wherein the outer circumferential edge portion is located higher than the inner circumferential edge portion with respect to a plane perpendicular to the central axis and passing through the inner circumferential edge portion.

A centrifugal pump including an outer case; an inner case; a first unit and a second unit placed in fluid communication with each other, each unit including a plurality of impellers; the inner case includes two half-parts joined along a connection plane containing the axis of rotation; a connecting element is placed between the first unit and the second unit, the connecting element is engaged with a last impeller of the first unit and with a last impeller of the second unit.

A non-return valve (19) for a water supply system (1) or a pump (4) is integrated in a flow channel (14) of the water supply system (1). The non-return valve (19) includes a sealing body (21) which is mounted within the channel (14), blocks the channel (14) in a first position forming the closure position and releases the channel (14) in a second position forming the opened position. The sealing body (21) is movably arranged on a holder (31) which includes a closure body (15), with which the holder (31) is releasably fastened in a housing opening.