Motor-compressor with stage impellers integrated in the motor-rotors

1. A motor-compressor comprising:

a casing;

at least one compressor stage arranged in the casing, the at least one compressor stage comprising:

an impeller arranged for rotation in the casing around a rotation axis and comprising a plurality of blades arranged around the rotation axis;

an embedded electric motor comprised of a motor stator and a motor rotor, wherein the motor stator circumferentially surrounds the impeller, and the motor rotor is integral with the impeller, and

a diffuser arrangement positioned radially between the plurality of blades and the motor rotor; and

a stationary component attached to the casing, wherein the stationary component is arranged upstream and downstream of the at least one compressor stage to support axially the at least one compressor stage.

2. The motor-compressor of claim 1 , wherein the at least one compressor stage further comprising a plurality of compressor stages.

3. The motor-compressor of claim 2 , wherein the impeller comprises the plurality of blades arranged around the rotation axis and forming vanes for a flow of process gas, the vanes extending from leading edges to trailing edges of the blades, and wherein the motor stator is arranged radially outwardly and at least partly around the blades of the respective impeller.

4. The motor-compressor of claim 1 , wherein the plurality of blades arranged around the rotation axis form vanes for a flow of process gas, the vanes extending from leading edges to trailing edges of the blades, and wherein the motor stator is arranged radially outwardly and at least partly around the blades of the impeller.

5. The motor-compressor of claim 4 , wherein the motor rotor of the impeller is located between the motor stator and the blades.

6. The motor-compressor of claim 5 , wherein the impeller further comprises the diffuser arrangement surrounding the blades and rotating therewith.

7. The motor-compressor of claim 1 , wherein the diffuser arrangement surrounds the blades and rotates therewith.

8. The motor-compressor of claim 1 , wherein the at least one compressor stage comprises a rotary disc in which the blades and the diffuser arrangement are formed, the rotary disc having a circumferential region surrounding the blades and the diffuser arrangement and housing the motor rotor.

9. The motor-compressor of claim 8 , wherein the motor stator surrounds the circumferential region of the rotary disc.

10. The motor-compressor of claim 9 , wherein the blades and the diffuser arrangement are formed monolithically in the rotary disc.

11. The motor-compressor of claim 8 , wherein the blades and the diffuser arrangement are formed monolithically in the rotary disc.

12. The motor-compressor of claim 11 , wherein the rotary disc forms a hub and a shroud of the impeller.

13. The motor-compressor of claim 1 ,

wherein the at least one compressor stage comprises an upstream compressor stage and a downstream compressor stage,

wherein the stationary component includes a stationary diaphragm i-s-arranged between the upstream and downstream compressor stages, and

wherein a return channel arrangement is provided in the stationary diaphragm, returning gas delivered at the outlet of an impeller of the upstream compressor stage towards an inlet of an impeller of the downstream compressor stage.

14. The motor-compressor of claim 1 , wherein the impeller comprises at least one axial bearing arranged between opposing radial surfaces of the impeller and the stationary component.

15. The motor-compressor of claim 1 , wherein the impeller is radially supported by the motor stator and the motor rotor.

16. The motor-compressor of claim 1 , wherein the at least one compressor having no shaft is supported radially within the case by the embedded electric motor.

17. The motor-compressor of claim 1 , wherein the stationary component disposed downstream of the at least one compressor stage includes a stationary diaphragm having a through-channel in fluid communication with the diffuser.

18. The motor-compressor of claim 1 , wherein the stationary component comprises:

an upstream stationary diaphragm disposed upstream of the at least one compressor stage, the upstream stationary diaphragm having a through-channel in fluid communication with the inlet of the motor-compressor and the impeller; and

a downstream stationary diaphragm disposed downstream of the at least one compressor stage, the downstream stationary diaphragm having a through-channel in fluid communication with diffuser and an outlet of the motor-compressor.

19. A shaftless motor-compressor comprising:

a casing; and

at least one compressor stage arranged in the casing; the at least one compressor stage comprising:

an impeller arranged for rotation in the casing around a rotation axis without a shaft;

an embedded electric motor housed in the casing and comprised of a motor stator and a motor rotor;

wherein the motor stator circumferentially surrounds the impeller, and the motor rotor is integral with the impeller, the motor rotor of the at least one compressor stage being arranged inside the motor stator;

wherein the impeller comprises a plurality of blades arranged around the rotation axis and forming vanes for a flow of process gas, the vanes extending from leading edges to trailing edges of the blades, and wherein the motor stator is arranged radially outwardly and at least partly around the blades of the impeller;

wherein the impeller further comprises a diffuser arrangement surrounding the blades and rotating therewith; and

wherein the diffuser arrangement is positioned radially between the blades and the motor rotor of the impeller; and

wherein the at least one compressor having no shaft is supported radially within the case by the embedded electric motor.