A head-mountable flow generator is configured to deliver a flow of breathable gas at a continuously positive pressure with respect to ambient air pressure to a patient interface in communication with an entrance to a patient's airways including at least an entrance of the patient's nares, while the patient is sleeping, to ameliorate sleep disordered breathing. The flow generator includes a motor, an impeller assembly and housing that encases the motor and the impeller assembly. The housing is configured to be mounted on the patient's head and comprises an inlet to receive the flow of breathable gas and a pair of opposing outlets to deliver the flow of breathable gas. In addition, the impeller assembly is configured to pressurize the flow of breathable gas received from the inlet, and the housing is configured to convey the pressurized flow of breathable gas through both outlets.

An impeller for a centrifugal fan rotatable about a central axis extending in an axial direction includes a hub portion expanding radially outward about the central axis, and wings on a radially outer side of the hub portion. A cross-sectional shape of the wing in a circumferential direction is a wing shape.

Embodiments of a hydraulic reservoir cooler include a backward curve centrifugal fan located rearward of a vented front cover of the cooler, the centrifugal fan having a center point “c” and a radius “r”; and a core area including fins and a manifold in fluid communication with a hydraulic fluid tank, the core area being located between the vented front cover and the backward curve centrifugal fan and including: a straight vertical portion extending in height less than an uppermost upper end of the centrifugal fan; a straight horizontal portion located above the uppermost upper end of the centrifugal fan; and a curved portion connecting the straight vertical and horizontal portions, the curved portion having a center point “C” and a radius “R”; where C is located above c and R is greater than r. The cooler may be adapted for use with an agricultural pumper truck.

A gear unit having a shaft, particularly an input shaft, a fan impeller being joined in rotatably fixed manner to the shaft, a fan cowl, which at least partially surrounds the fan impeller, being mounted on the gear housing, a separating plate for separating the pressure chamber of the fan from the suction chamber of the fan being joined to the fan cowl, the separating plate having an air inlet for the fan impeller and being disposed on the side of the fan impeller facing away axially from the gear unit.

Each of a plurality of blades of a turbofan includes a thick wall portion, a thin wall portion and a stepped portion. The stepped portion is formed between the thick wall portion and the thin wall portion. A plate thickness of the stepped portion is progressively decreased toward a positive pressure surface of the blade in a direction that is directed from the thick wall portion toward the thin wall portion. In the blade, a first curved surface forms a negative pressure surface of the thick wall portion, and a second curved surface forms a negative pressure surface of the thin wall portion while the second curved surface is located on a side of the first curved surface where the positive pressure surface of the blade is placed, and a negative pressure surface of the stepped portion connects between the first curved surface and the second curved surface.

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.

A cleaner reduces noise. The cleaner includes a motor, a fan including a number Z of blades and rotatable at a rotational speed N, indicating revolutions per minute, about a rotation axis by the motor, a cover having an inlet located frontward from the fan, and a number V of ribs located in the inlet. The ribs extend in a radial direction from the rotation axis and are arranged in a circumferential direction about the rotation axis. The fan is rotatable to produce noise having a frequency f.sub.NZ of 20,000 Hz or higher, and f.sub.NZ=(m−k×V)×N/60 and m=n×Z+k×V, where n is an order, m is an integer, and k is an integer.

A breathing assistance apparatus has a pressurised gases source featuring a lightweight impeller with a plastic shaft. The impeller is shroudless. The plastic shaft is supported within the stator by a bearing structure. A resilient motor mount couples the statos and the housing and provide compliance and/or damping for the motor.

A fan blade (1) has a front leading edge (2) and a rear trailing edge (3). The fan blade (1) has a leading edge (4), at least some portions, that are undulated. The edge forms a wave (W) with a specific three-dimensional waveform.

An impeller connected to a motor having a drive shaft includes a back plate having a boss having a shaft hole through which the drive shaft is inserted, a ring-shaped rim provided to face the back plate, and a plurality of blades connected to the back plate and the rim and arranged along a circumferential direction of the back plate about the rotation shaft. The back plate includes a first surface portion on which the plurality of blades are formed, a second surface portion provided at a region between the boss and the first surface portion and depressed from the first surface portion in an axial direction of the rotation shaft, and a plurality of projections provided at the second surface portion and extending in the axial direction.