An impeller for a ventilation unit, especially for use in plants for the aerobic treatment of organic waste, is provided. The impeller comprises a housing, a pair of mutually facing plates received within the housing and provided centrall with a through-hole for a cylindrical hub, and a plurality of first radial blades arranged between the plates. The impeller further comprises second radial blades arranged on at least one plate, on its side facing the inner wall of the housing and extending from the cylindrical hub toward the periphery for creating an under-pressure zone in the central region of the impeller itself, at its hub. Thanks to this measure, condensate water deriving from the humidity of the air sucked/blown by the ventilation unit is prevented from leaking along the rotation shaft of the impeller, towards its motor and towards the outside environment.

A rotating assembly adapted for use in turbines and pumps is provided. The rotating assembly includes a shroud that rotates around a central axis and a disk seated in a recess in the shroud so that the disk rotates with the shroud, the disk being oriented perpendicular to the central axis. The rotating assembly also includes a stationary element in which at least one surface of the disk contacts a fluid so that when the fluid flows under pressure, the surface of the disk resists the generation of drag between the surface and the stationary element of the rotating assembly. A shroud is provided that includes a circular recess with a cavity on an outer perimeter extending away from the fixed assembly. A method of manufacturing a rotating assembly is provided.

A side channel machine arrangement comprises a side channel machine (1) and a fluid connection device (2). The side channel machine (1) has a housing (5), side channels arranged in the housing (5) and fluid inlet openings (11) provided in said housing, which have a flow connection to the side channels to introduce a fluid to be conveyed into the side channels, at least one fluid outlet, which is provided on the housing (5) and has a flow connection to the side channels to discharge the fluid from the side channels, and an impeller that is mounted so that it can be rotatably driven in the housing (5). The fluid connection device (2) is used to connect the side channel machine (1) to a fluid supply line. It comprises a first fluid connection mechanism (3), which is provided on the housing (5) and has a flow connection to the fluid inlet openings (11), and a second fluid connection mechanism (4), which has a fluid inlet piece (29) for connection to the fluid supply line.

The invention first relates to an air filter attachment (4) for a turbomachine, in particular a side channel compressor, comprising a housing, comprising a filter material (8) arranged in a housing interior, and comprising an inlet (9) and an outlet (10) which are formed in the housing, which have a free opening cross section, and through which air is suctioned. The aim of the invention is to advantageously design a turbomachine comprising an air filter attachment. This is achieved in that the housing interior that has the filter material (8) extends laterally relative to the opening cross section of the inlet (9) and/or the outlet (10) in a non-uniform manner and in any case in a direction by a magnitude of 1 or more times the dimension from a central axis (M) of the respective opening cross section to a periphery of the opening cross section in the direction. The invention further relates to a turbomachine, in particular a side channel compressor, comprising such an air filter attachment. Additionally, the invention relates to a filter part (12, 19) consisting of a pleated filter material (8) or a circumferential filter wall (21) which is connected to a base part (22) and which consists of a filter material.

A method for pressure and temperature control of fluid in a series of cryogenic compressors. An actual speed for each compressor and an actual inlet pressure and actual inlet temperature at entry are determined. The maximum speed for each compressor and a desired inlet pressure for the first compressor is provided. A speed index for each compressor is determined from the maximum speed and actual speed of each compressor. A proportional value is determined from the deviation of the actual and desired inlet pressure. A priority value is determined from the smaller of the proportional value and the smallest speed index. A desired inlet temperature for the first compressor and a desired speed for each compressor are determined from the priority value. The actual inlet temperature is adjusted to the determined desired inlet temperature and the actual speed for each compressor is adjusted to the determined desired speed.

A method for controlling speeds of compressors arranged in series for compressing a fluid. The desired inlet pressure is predefined and the actual inlet pressure is detected. The actual discharge pressure of the fluid is recorded and the actual total pressure ratio is recorded. A proportional integral value is determined from the deviation of the actual inlet pressure from the desired inlet pressure and a capacity factor is determined from the proportional integral value and the actual total pressure ratio. A model total pressure ratio is determined from the actual total pressure ratio and the capacity factor. A reduced desired speed for each compressor is determined as a function value of the control function associated with the respective compressor. The control function assigns a reduced desired speed to each value pair of capacity factor and model total pressure ratio and is used to adjust the speed of each compressor.

A rotor assembly is provided and includes a two-piece rotor impeller and a rotor shaft. The two-piece rotor impeller includes a blade section and a forward section, which is connected to the blade section. The rotor shaft includes an aft section at which the rotor shaft terminates. The aft section is directly attached to the forward section of the rotor impeller. The blade section includes a converging blade configured to converge to a point with a minimized internal diameter (ID).

A rotor assembly is provided and includes a two-piece rotor impeller and a rotor shaft. The two-piece rotor impeller includes a blade section and a forward section, which is connected to the blade section. The rotor shaft includes an aft section at which the rotor shaft terminates. The aft section is directly attached to the forward section of the rotor impeller. The blade section includes a converging blade configured to converge to a point with a minimized internal diameter (ID).

The centrifugal compressor described includes an impeller shroud which encloses the impeller and has a curved shroud surface that extends between an inducer portion and an exducer portion. The compressor includes one or more circumferential grooves in the shroud body within the exducer portion. Each groove has opposed wall segments spaced apart therefrom. The wall segments are inclined at a nonzero groove angle relative to a normal of the shroud surface in a direction opposite the fluid flow path along the shroud surface.

A device for an anode gas recirculation in a fuel cell system includes a blower, an outer housing defining the blower, a condensate drain channel, a receiving element arranged at the outer housing, and a drain valve arranged in the receiving element. The blower incudes a rotor wheel, a delivery channel, an electric motor having a drive shaft to which the rotor wheel is attached, and a cooling channel through which an anode gas flows. The delivery channel extends from a delivery channel inlet to a delivery channel outlet. The cooling channel at least partially surrounds the electric motor of the blower. The condensate drain channel extends below the cooling channel in the outer housing. The cooling channel is fluidically connected to the condensate drain channel. The condensate drain channel is opened and closed by the drain valve so that a liquid can be drained from the condensate drain channel.