Abstract: A cylindrical symmetric volumetric machine, includes a housing (2) with an inlet opening (3) and an outlet opening (4), with an outer rotor (6a) which is mounted rotatably in the housing (2) and an inner rotor (6b) which is mounted rotatably in the outer rotor (6a), whereby liquid is injected in the machine (1). At the outlet opening (4) on the level of the inner rotor (6b) and outer rotor (6a) a liquid separation takes place, whereby the separated liquid ends up in the machine (1) again, and in that the outer rotor (6a) has an axial extension (17) on the level of the outlet opening (4) which extends around this outlet opening (4) almost up against the housing (2) such that a space (19) is located between the axial extension (17) and the housing (2).

Abstract: A cylindrical symmetric volumetric machine, includes a housing (2) with two co-operating rotors (6a, 6b) therein, namely an outer rotor (6a) mounted rotatably in the housing (2) and an inner rotor (6b) mounted rotatably in the outer rotor (6a), whereby a compression chamber (8) is located between the rotors (6a, 6b), which will move by rotation of the rotors (6a, 6b) from the inlet side (9a) of the rotors (6a, 6b) to the outlet side (9b) of the rotors (6a, 6b), wherein the inlet side (9a) of the outer rotor (6a) is provided with a ventilator (12), to supply air to the compression chamber (8).

Abstract: Cylindrical symmetric volumetric machine (1), which machine (1) includes two cooperating rotors (6a, 6b), namely an outer rotor (6a) which is rotatably mounted in the machine (1) and an inner rotor (6b) which is rotatably mounted in the outer rotor (6a), whereby the machine (1) is provided with an electric motor (15) with a motor rotor (16) and a motor stator (17) to drive the outer and inner rotor (6a, 6b), characterised in that the electric motor (15) is mounted around the outer rotor (6a), whereby the motor stator (17) is directly driving the outer rotor (6a), and whereby the electric motor (15) extends along only a part of the length (L) of the outer rotor (6a) and the inner rotor (6b), whereby the motor (15) is located at an end (9b) of the inner rotor (6b) with a smallest diameter (D).

Abstract: A cylindrical symmetric volumetric machine, includes a housing (2) with two co-operating rotors (6a, 6b) therein, namely an outer rotor (6a) mounted rotatably in the housing (2) and an inner rotor (6b) mounted rotatably in the outer rotor (6a), whereby a compression chamber (8) is located between the rotors (6a, 6b), which will move by rotation of the rotors (6a, 6b) from the inlet side (9a) of the rotors (6a, 6b) to the outlet side (9b) of the rotors (6a, 6b), wherein the inlet side (9a) of the outer rotor (6a) is provided with a ventilator (12), to supply air to the compression chamber (8).

Abstract: A cylindrical symmetric volumetric machine, includes a housing (2) with an inlet opening (3) and an outlet opening (4), with an outer rotor (6a) which is mounted rotatably in the housing (2) and an inner rotor (6b) which is mounted rotatably in the outer rotor (6a), whereby liquid is injected in the machine (1). At the outlet opening (4) on the level of the inner rotor (6b) and outer rotor (6a) a liquid separation takes place, whereby the separated liquid ends up in the machine (1) again, and in that the outer rotor (6a) has an axial extension (17) on the level of the outlet opening (4) which extends around this outlet opening (4) almost up against the housing (2) such that a space (19) is located between the axial extension (17) and the housing (2).

Abstract: Cylindrical symmetric volumetric machine (1), which machine (1) includes two cooperating rotors (6a, 6b), namely an outer rotor (6a) which is rotatably mounted in the machine (1) and an inner rotor (6b) which is rotatably mounted in the outer rotor (6a), whereby the machine (1) is provided with an electric motor (15) with a motor rotor (16) and a motor stator (17) to drive the outer and inner rotor (6a, 6b), characterised in that the electric motor (15) is mounted around the outer rotor (6a), whereby the motor stator (17) is directly driving the outer rotor (6a), and whereby the electric motor (15) extends along only a part of the length (L) of the outer rotor (6a) and the inner rotor (6b), whereby the motor (15) is located at an end (9b) of the inner rotor (6b) with a smallest diameter (D).

Abstract: An aerator for aerating water comprises a distribution system for distributing air below the water surface and a compressor with an air inlet and at least one air outlet. The compressor is configured to be placed below the water surface. The infiltration of water at the air inlet is prevented by an intake pipe with one open end above the water surface and the other open end has a watertight connection to the compressor. The distribution system has a watertight connection to the air outlet and, due to its nature or by at least one valve, can hold back water. The housing is in thermal contact with the water to cool the compressor. The compressor is a centrifugal compressor that comprises an impeller that is driven by a shaft that it is mounted on air bearings, magnetic bearings or both.

Abstract: An aerator for aerating water comprises a distribution system for distributing air below the water surface and a compressor with an air inlet and at least one air outlet. The compressor is configured to be placed below the water surface. The infiltration of water at the air inlet is prevented by an intake pipe with one open end above the water surface and the other open end has a watertight connection to the compressor. The distribution system has a watertight connection to the air outlet and, due to its nature or by at least one valve, can hold back water. The housing is in thermal contact with the water to cool the compressor. The compressor is a centrifugal compressor that comprises an impeller that is driven by a shaft that it is mounted on air bearings, magnetic bearings or both.

Abstract: A high-pressure multi-stage centrifugal compressor is provided containing at least three compressor elements which are arranged in series as compressor stages, and at least two electric motors to drive these compressor elements. At least one compressor element forms a low-pressure stage which is driven by an electric motor. At least two compressor elements form high-pressure stages, and are arranged in series and driven by one and the same second electric motor.

Abstract: The invention concerns a high-pressure multi-stage centrifugal compressor containing at least two compressor elements (1, 4, 5) which are arranged in series as compressor stages, and at least two electric motors (3, 7) to drive these compressor elements (1, 4, 5), characterised in that, apart from at least one compressor element (1) forming a low-pressure stage and which is driven by an electric motor (3), it contains at least two compressor elements (4, 5) forming high-pressure stages and which are arranged in series and are driven by one and the same second electric motor (7).