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.

The present invention relates to an air compressor for a vehicle and, more specifically, to an air compressor for a vehicle wherein the entire operation of the air compressor may be stabilized by a cooling unit in which a portion of the compressed air that moves through a connection pipe conveying primarily compressed air exchanges heat with a cooling water flowing part to cool the driving unit.

A pump shaft for a multi-stage pump, in particular a centrifugal pump, includes a peripheral groove region for the engagement of a relief device in order to introduce a force acting in the axial direction of the pump shaft. The groove region includes a plurality of grooves which are spaced apart in the axial direction.

A pump shaft for a multi-stage pump, in particular a centrifugal pump, includes a peripheral groove region for the engagement of a relief device in order to introduce a force acting in the axial direction of the pump shaft. The groove region includes a plurality of grooves which are spaced apart in the axial direction.

A method for machining ribs or grooves on a workpiece such as a shaft or an air or gas axial bearing intended to be rotated about a longitudinal axis of a centrifugal compressor. All of the ribs or grooves are obtained at once by the machining tool on a workpiece portion driven such that it rotates, by moving the workpiece or the tool holder in a longitudinal machining direction, the machining tool moving back and forth with a machining position in contact with the workpiece and a position wherein it is not in contact with the workpiece from the start to the end of the workpiece portion. The back-and-forth movements of the machining tool are synchronised with the sinusoidal program set up in the machining unit, as well as with the desired, programmed arrangement of the ribs or grooves to be produced on the workpiece portion.

A compressor or pump stage is provided. The compressor or pump stage at least comprising a central shaft (8) and one rotor (3), where the axis of rotation of the rotor (3) is the central shaft (8) and where the rotor comprises a number, n, of rows of impellers (5) arranged at an outer perimeter of the rotor with an axial distance between neighbouring rows of impellers (5), where n={2, 3, 4 . . . }.

A compressor that vibrates a rotary shaft or changes an operating frequency of a motor, in response to a vibration frequency of a discharge passage falling outside of a normal range. The compressor may include one or more impeller configured to draw in and compress refrigerant; a motor configured to rotate the one or more impeller; a rotary shaft, to which the one or more impeller and the motor are coupled; at least two thrust bearings that limit vibration of the rotary shaft; a vibration measuring sensor configured to measure a vibration frequency of a discharge passage; and a controller configured to control the at least two thrust bearings based on the vibration frequency. Upon determining that the vibration frequency falls outside of a normal vibration frequency range, the controller controls the at least two thrust bearings to vibrate the rotary shaft a predetermined number of times.

A compressor that vibrates a rotary shaft or changes an operating frequency of a motor, in response to a vibration frequency of a discharge passage falling outside of a normal range. The compressor may include one or more impeller configured to draw in and compress refrigerant; a motor configured to rotate the one or more impeller; a rotary shaft, to which the one or more impeller and the motor are coupled; at least two thrust bearings that limit vibration of the rotary shaft; a vibration measuring sensor configured to measure a vibration frequency of a discharge passage; and a controller configured to control the at least two thrust bearings based on the vibration frequency. Upon determining that the vibration frequency falls outside of a normal vibration frequency range, the controller controls the at least two thrust bearings to vibrate the rotary shaft a predetermined number of times.

A compressor rotor for turbomachinery, such as a compressor, is provided. Disclosed embodiments can benefit from seal elements that may be arranged to inhibit passage onto respective hirth couplings of process fluid being processed by the compressor. A seal element may be affixed to adjacent rotor components (e.g., adjacent impeller bodies) by way of a slip or interference fit connection to one of the adjacent components and may be affixed to the other adjacent rotor component by way of a elastically flexible frustoconical inner surface of the seal element that permits the seal element to be placed in a spring-loaded condition, which generates a biasing force to circumferentially clamp onto a frustoconical outer surface of the other adjacent rotor component. This arrangement is conducive to user-friendly assembly/disassembly of the seal elements with respect to the adjacent rotor components.

A centrifugal compressor assembly and method of operation provides a motor that drives a first stage compressor. The motor comprises a rotor. The motor uses radial aerostatic bearings to stabilize rotation and axial displacement of the rotor. The motor also uses a thrust aerostatic bearing to balance an axial force of the rotor. The radial aerostatic bearings and the thrust aerostatic bearing use a low-viscous vapor-liquid two-phase fluid as a lubricating medium. The radial aerostatic bearings supports the rotor. The thrust aerostatic bearing uses porous aerostatic bearings that use a low-viscous vapor-liquid two-phase fluid, so as to reduce radial and axial oscillation of the rotor. This enables clearance between a blade tip of an impeller and a volute. This causes a seal clearance to be reduced by a half; thereby increasing efficiency of the centrifugal compressor by at least 10 percent.