Abstract: Centrifugal high-pressure machine comprising an impeller blade rotor positioned within a housing and a spiral chamber surrounding the housing and forming with the blade rotor a diffuser chamber. The machine is provided with an axially movable piston member which with an outer wall and an enclosure member constitutes a chamber of various volume. The chamber is arranged to be connected to the inlet of the machine and to the spiral chamber respectively. The piston member is positioned against a side wall of the blade rotor and has a lateral face congruent with that of the blade rotor. The axial movement of the piston member constitutes diffuser chambers of various geometry and volume.

Abstract: The centrifugal fan includes a housing of a substantially cylindrical shape having lateral walls and provided with an inlet port located at one of the lateral walls. An impeller is supported for rotation within the housing in the area of the second lateral wall opposite to the aforementioned one wall. The centrifugal fan is provided with a partition formed as a plurality of annular telescopically engaged elements or bellows. The partition subdividing the interior of the housing into a main diffusing chamber in the area of the impeller and a diffusing antechamber in the area of the inlet port is axially displaced by control arms to thus vary the area of communication between those two chambers.

Abstract: The centrifugal fan comprises a casing having a cylindrical jacket with a tangentially directed outlet duct and lateral walls, one of the walls being formed with an axially directed inlet duct partially projecting into the casing, an impeller wheel supported for rotation in the casing opposite the opening of the inlet duct, and axially displaceable tubular partition coaxially surrounding the inlet duct and projecting into the casing toward the face of the impeller wheel to define therewith a variable gap which connects an adjustable diffusing antechamber resulting in the casing between the displaceable tubular partition and the inlet duct to a main diffusing chamber resulting between the displaceable tubular partition and the cylindrical jacket.