Integrated motor-compressor assembly

Abstract

The integrated motor-compressor assembly (1) comprises: - a gas input (7), - a drive shaft (3), - magnetic bearings (9, 10) supporting the drive shaft (3), - an electric motor (2) mounted on a drive shaft, - a first compression section (4) in overhung at a first end of the drive shaft and configured to compress a gas flowing at the gas input of the integrated motor-compressor assembly, and - a second compression section (5) in overhung at a second end of the drive shaft. The integrated motor-compressor assembly further comprises a cooling fan (12) in overhung mounted on the drive shaft (3) between one compression section of the first or the second compression sections (4, 5) and the electric motor (2), the cooling fan being configured to circulate a part of the gas taken at the gas input of the integrated motor-compressor assembly in a cooling loop (11) of the integrated motor-compressor assembly, the part of the gas being a cooling gas.

Description

[0001] DESCRIPTION

[0002] TITLE: INTEGRATED MOTOR-COMPRESSOR ASSEMBLY

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to an integrated motor-compressor assembly and relates in particular to a specific arrangement of a cooling fan.

[0005] DESCRIPTION OF RELATED ART

[0006] An integrated motor-compressor assembly may comprise an electric motor mounted on a drive shaft to drive the said shaft. The drive shaft is generally supported in rotation by two magnetic bearings arranged on each side of the electric motor.

[0007] A compression section may be arranged at each end of the drive shaft.

[0008] The electric motor and the magnetic bearings are subj ected to losses generated for example by eddy currents.

[0009] In order to cool the electric motor and the magnetic bearings, the integrated motor-compressor assembly comprises a cooling loop compri sing a filtering device filtering a part of a gas compressed by a first compression section, the part of compressed gas being the cooling gas flowing in the electric motor and the bearings.

[0010] As the pressure of the compressed gas is too high to supply the cooling loop, a control valve expands the compressed gas filtered by the filtering device to decrease the pressure of the compressed gas at a predetermined pressure.

[0011] However, in order to decrease the pressure of the cooling gas, the control valve di ssipates a part of energy used to drive the first compression section to compress the gas so that the efficiency of the integrated motor-compressor assembly is deteriorated.

[0012] Further, the control valve is a pressure regulated component which may be defective decreasing the reliability of the integrated motor-compressor assembly. There is a need to avoid at least some of the previously- mentioned drawbacks.

[0013] SUMMARY

[0014] According to an aspect, a new integrated motor-compressor assembly is proposed.

[0015] The integrated motor-compressor assembly comprises :

[0016] - a gas input,

[0017] - a drive shaft, magnetic bearings supporting the drive shaft,

[0018] - an electric motor mounted on a drive shaft,

[0019] - a first compression section comprising an axial gas input and in overhung at a first end of the drive shaft and configured to compress a gas flowing at the gas input of the integrated motor-compressor assembly, and

[0020] - a second compression section comprising an axial gas input and in overhung at a second end of the drive shaft.

[0021] The integrated motor-compressor assembly further comprises a cooling fan arranged in overhung and mounted on the drive shaft between one compression section of the first or the second compression sections and the electric motor, the cooling fan being configured to circulate a part of the gas taken at the gas input of the integrated motorcompressor assembly in a cooling loop of the integrated motorcompressor assembly, the part of the gas being a cooling gas, the cooling loop being configured to cool down the magnetic bearings and an electric motor of the integrated motor-compressor assembly, the cooling fan comprising a casing and a compression wheel arranged in the casing.

[0022] Preferably, the cooling fan is mounted between the first compression section and the electric motor, and i s configured to compress the cooling gas to supply the cooling loop of the integrated motor-compressor assembly with the compressed cooling gas.

[0023] Advantageously, the integrated motor-compressor assembly compri ses the cooling loop including a filtering device, the filtering device being connected to the cooling fan and to the electric motor so that a first part of the compressed cooling gas filtered by the filtering device flows through the electric motor to cool the electric motor.

[0024] Preferably, the filtering device is further connected to each magnetic bearing so that a second part of the compressed cooling gas filtered by the filtering device flows through the magnetic bearings to cool the magnetic bearings.

[0025] Advantageously, the integrated motor-compressor assembly further comprises a watertight casing, the drive shaft, the electric motor, the first compression section, the second compression section, the cooling fan and the magnetic bearings being arranged in the watertight casing, the cooling loop further comprising an exhaust duct configured to exhaust the first part of the compressed cooling gas, heated by the electric motor, released inside the watertight casing and to exhaust the second part of the compressed cooling gas, heated by the magnetic bearings, released inside the watertight casing.

[0026] Preferably, the cooling fan is configured to aspirate the cooling gas.

[0027] Advantageously, the integrated motor-compressor assembly further comprises the cooling loop comprising a filtering device connected to the gas input and to the electric motor so that a first part of the cooling gas filtered by the filtering device flows through the electric motor to cool the electric motor, the cooling gas heated by the electric motor being aspirated by the cooling fan.

[0028] Preferably, the cooling fan comprises a gas output configured to deliver the cooling gas aspirated by the cooling fan, the integrated motor-compressor assembly further comprises:

[0029] - a watertight casing, the drive shaft, the electric motor, the first compression section, the second compression section and the cooling fan being arranged in the watertight casing,

[0030] - a suction device configured to aspirate gas leaking inside the watertight casing from the compression section of the first or the second compression sections farthest from the cooling fan and to inj ect the aspirated gas in a gas input of the first or the second compression section, - a gas diffuser configured to be fed with a second part of the filtered cooling gas and diffuse the second part of the filtered cooling gas in the watertight casing,

[0031] - the gas diffuser being arranged between the electric motor and the compression section of the first or the second compression sections farthest from the cooling fan and the suction device being arranged between the compression section of the first or the second compression sections farthest from the cooling fan and the gas diffuser, and

[0032] - a buffer gas system connected to the gas output of the cooling fan and arranged between the gas diffuser and the suction device, and configured to diffuse a part of the cooling gas aspirated by the cooling fan.

[0033] Advantageously, the filtering device is further connected to each magnetic bearing so that a third part of the filtered cooling gas flows through the magnetic bearings to cool the magnetic bearings, the cooling gas heated by the magnetic bearings being aspirated by the cooling fan.

[0034] Preferably, the filtering device i s arranged outside the watertight casing.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Other advantages and features of the invention will appear on examination of the detailed description of embodiments, in no way restrictive, and the appended drawings in which :

[0037] [Fig 1 ] illustrates schematically a first embodiment of an integrated motor-compressor assembly according to the invention;

[0038] [Fig 2] illustrates schematically a second embodiment of the integrated motor-compressor assembly according to the invention;

[0039] [Fig 3 ] illustrates schematically a third embodiment of the integrated motor-compressor assembly according to the invention; and

[0040] Fig 4] illustrates schematically a fourth embodiment of the integrated motor-compressor assembly according to the invention.

[0041] DETAILED DESCRIPTION Reference is made to Figure 1 which represents schematically a first embodiment of an integrated motor-compressor assembly 1.

[0042] The integrated motor-compressor assembly 1 includes an electric motor 2 mounted on a drive shaft 3 , two compression sections 4, 5 and a watertight casing 6.

[0043] The electric motor 2 and the two compression sections 4, 5 are arranged in the watertight casing 6.

[0044] A first compression section 4 is in overhung at a first end of the drive shaft 3 and the second compression section 5 is in overhung at the second end of the drive shaft 3.

[0045] Each compression section 4, 5 includes a gas input 4a, 5 a and a gas output 4b, 5b .

[0046] As represented, the gas input 4a, 5a of each compression section 4, 5 may be an axial gas input.

[0047] The gas input 4a of the first compression section 4 is connected to a gas input 7 of the integrated motor-compressor assembly 1 , the gas input 5 a of the second compression section 5 is connected to the gas output 4b of the first compression section 4 and the gas output 5b of the second compression section 5 is connected to ta gas output 8 of the integrated motor-compressor assembly 1 .

[0048] Each compression section 4, 5 may comprise one compression wheel 4c, 5c.

[0049] Each compression section 4, 5 comprises sealing devices 4d, 5 d to prevent gas leaking in the watertight casing 6 from the said compression section 4, 5.

[0050] The first compression section 4 is intended to be driven by the electric motor 2 to compress a gas flowing in the gas input 7 of the integrated motor-compressor assembly 1 and to deliver the compressed gas to the gas input 5a of the second compression section 5.

[0051] The second compression section 5 is intended to be driven by the electric motor 2 to further compress the gas delivered by the first compression section 4 and to deliver the compressed gas further compressed by the second compression section 5 to the gas output 8 of the integrated motor-compressor assembly 1. The drive shaft 3 i s supported by two bearings 9, 10 in the watertight casing 6.

[0052] Each bearing 9, 10 comprises a radial bearing and an axial bearing.

[0053] The first and second compression sections 4, 5 are in overhung.

[0054] The bearings 9, 10 may comprise gas bearings or preferably magnetic bearings.

[0055] It is assumed in the following that the bearings 9, 10 are magnetic bearings, each bearing 9, 10 compri ses a radial magnetic bearing and / or an axial magnetic bearing.

[0056] A first bearing 9 i s arranged between the first compression section 4 and the electric motor 2, and the second bearing 10 is arranged between the second compression section 5 and the electric motor 2.

[0057] The integrated motor-compressor assembly 1 further comprises a cooling loop 1 1 and a cooling fan 12.

[0058] The cooling fan 12 i s mounted in overhung on the drive shaft 3 between the first compression section 4 and the electric motor 2.

[0059] This integrated motor-compressor assembly 1 allows to make a double overhung integrated motor-compressor assembly combined with a fan 12 in place of a control valve known from the prior art which generates a lot of pressure drop and debit drop in the assembly .

[0060] The cooling fan 12 driven by the drive shaft 3 i s intended to circulate a part of the gas taken at the gas input 7 of the integrated motor-compressor assembly 1 in the cooling loop 1 1.

[0061] The part of the gas taken at the gas input 7 of the integrated motor-compressor assembly 1 is named cooling gas.

[0062] The cooling fan 12 comprises a gas input 12a connected to the gas input 7 of the integrated motor-compressor assembly 1 , a gas output 12b, a compression wheel 12c, a casing 12e and sealing devices 12d to prevent that the gas compressed by the cooling fan 12 leaks in the watertight casing 6. The compression wheel 12c is arranged in the casing 12e of the cooling fan 12.

[0063] The cooling loop 1 1 includes a filtering device 13 comprising an input 13 a connected to the gas output 12b of the cooling fan 12, and an output 13b connected to the electric motor 2 and / or the magnetic bearings 9, 10.

[0064] The sealing devices 4d, 5 d may compri se labyrinths and may further comprise intermediate connection lines (not represented) connected to the gas input 7 and to the output 13b of the filtering device 13. Arrangement of the labyrinths and different connection lines is made so that no unfiltered gas can enter bearing and compressor elements, such as magnetic bearings 9, 10 and electric motor 2.

[0065] Each intermediate connection line may for example comprise a pipe.

[0066] The sealing device 12d may comprise labyrinths and may further compri se intermediate connection to the output 13b .

[0067] The sealing devices 4d, 5d and 12d avoid that unfiltered gas flows inside the magnetic bearings 9, 10 and the electric motor 2.

[0068] The integrated motor-compressor assembly 1 further comprises an exhaust duct 14 connecting the inside of the watertight casing 6 to the gas input 7 of the integrated motor-compressor assembly 1.

[0069] When the electric motor 2 drives the drive shaft 3 , the cooling fan 12 compresses the cooling gas to supply the cooling loop 1 1 with compressed cooling gas and the filtering device 13 filters the compressed cooling gas. The compressed cooling gas flows in the electric motor 2 and / or the magnetic bearings 9, 10.

[0070] A first part of the compressed cooling gas filtered by the filtering device 13 flows through the electric motor 2 to cool the electric motor 2 and a second part of the compressed cooling gas filtered by the filtering device 13 flows through the magnetic bearings 9, 10 to cool the magnetic bearings 9, 10.

[0071] The first part of compressed cooling gas heated by the electric motor 2 and the second part of compressed cooling gas heated by the magnetic bearings 9, 10 are released inside the watertight casing 6.

[0072] The heated cooling gas released in the watertight casing 6 is exhausted through the gas input 7 of the integrated motor-compressor assembly 1 via the exhaust duct 14. The cooling fan 12 is designed so that the pressure at the gas output 12b is equal to a predetermined pressure determined according to the cooling gas flow circulating in the electric motor 2 and / or the magnetic bearings 9, 10, and according to the pressure drop in the cooling loop 1 1 .

[0073] As represented, the filtering device 13 may be arranged outside the watertight casing 6.

[0074] In variant, the filtering device 13 may be arranged inside the watertight casing 6.

[0075] Unfiltered gas flowing in the gas input 7 may include particles likely to damage components inside the watertight casing 6, for example to damage the magnetic bearings 9, 10 and / or the electric motor 2.

[0076] The particles may be corrosion product from process piping, rust, water droplets carried over by process flow or any solid particle present in the processed gas flowing in the gas input 7.

[0077] The filtering device 13 is designed to remove these components from the gas flowing in the gas input 7 of the integrated motorcompressor assembly 1.

[0078] The cooling fan 12 may be arranged close to the first compression section 4 so that the gas which may leak from the first compression section 4 through the sealing devices 4d of the first compressions section 4 flows in the cooling fan 12 to prevent unfiltered gas flowing inside the watertight casing 6.

[0079] Figure 2 represents schematically a second embodiment of the integrated motor-compressor assembly 1 .

[0080] The same references designate the same elements as previously referenced in the first embodiment of the integrated motor-compressor assembly 1 represented in figure 1.

[0081] The integrated motor-compressor assembly 1 comprises the electric motor 2, the drive shaft 3 , the first and the second compression sections 4, 5, the watertight casing 6, the gas input 7, the gas output 8 and the magnetic bearings 9, 10 arranged as described above in the first embodiment of the integrated motor-compressor assembly 1. The integrated motor-compressor assembly 1 further comprises the cooling fan 12 in overhung and the filtering device 13.

[0082] As exposed in the following, in the second embodiment, the cooling fan 12 is intended to aspirate cooling gas.

[0083] The gas input 12a of the cooling fan 12 is arranged in the watertight casing 6 to aspirate gas in the watertight casing 6 and the gas output 12b of the cooling fan 12 is connected to the gas input 7 of the integrated motor-compressor assembly 1 .

[0084] The cooling fan 12 i s mounted on the drive shaft 3 between the first compression section 4 and the electric motor 2.

[0085] The integrated motor-compressor assembly 1 comprises a cooling loop 15 comprising the filtering device 13.

[0086] The input 13 a of the filtering device 13 is connected to the gas input 7 of the integrated motor-compressor assembly 1 and the output 13b of the filtering device 13 is connected to the electric motor 2 and the magnetic bearings 9, 10.

[0087] When the electric motor 2 drives the drive shaft 3 , the cooling fan 12 creates a depression inside the watertight casing 6 so that a part of the gas taken at the gas input 7 of the integrated motor-compressor assembly 1 (cooling gas) is aspirated through the filtering device 13 to be filtered. Then the filtered cooling gas may be divided in a first part, a second part and a third part. The first part of the filtered cooling gas is aspirated through the electric motor 2 and the second part of the filtered cooling gas is aspirated through the magnetic bearings 9, 10.

[0088] The first part of compressed cooling gas heated by the electric motor 2 and the second part of compressed cooling gas heated by the magnetic bearings 9, 10 released inside the watertight casing 6 are aspirated by the cooling fan 12 and pushed by the cooling fan 12 in the gas input 7 of the integrated motor-compressor assembly 1.

[0089] As the inside of the watertight casing 6 is in depression, to avoid that unfiltered gas in the first compression section 4 leaks inside the watertight casing 6, the cooling fan 12 may be adj acent to the first compression section 4. The integrated motor-compressor assembly 1 may comprise a gas diffuser 16 between the electric motor 2 and the second compression section 5 , and a suction device 17 arranged between the second compression section 5 and the gas diffuser 16 to avoid that unfiltered gas in the second compression section 5 leaks inside the watertight casing 6.

[0090] The gas diffuser 16 is fed with the third part of the filtered cooling gas and diffuses the third part of the filtered cooling gas in the watertight casing 6, the third part of the filtered cooling gas forming a gas barrier.

[0091] The suction device 17 aspirates gas leaking inside the watertight casing 6 from the compression section of the first or the second compression sections 4, 5 which is arranged farthest from the cooling fan 12 and inj ects the aspirated gas in the gas input of the integrated motor-compressor assembly 1.

[0092] The integrated motor compressor assembly 1 further comprises a buffer gas system 18 connected to the gas output 12b of the cooling fan 12 and arranged between the gas diffuser 16 and the suction device 17.

[0093] The buffer gas system 18 is fed with a part of the cooling gas aspirated by the cooling fan 12 and diffuses the said part of cooling gas to create a buffer zone in slight over pressure preventing that unfiltered gas leaking form the suction device 17 flows into the gas diffuser 16 and flows in the watertight casing 6.

[0094] In this embodiment, the suction device 17 aspirates gas leaking from the second compression section 5 inside the watertight casing 6 and inj ects the aspirated gas in the gas input 5 a of the second compression section 5.

[0095] In this embodiment, the cooling fan 12 is designed so that the pressure at the output 13b of the filtering device 13 is equal to a predetermined pressure determined according to the cooling gas flow circulating in the electric motor 2 and / or the bearings 9, 10, and according to the pressure drop in the cooling loop 15.

[0096] As represented, the filtering device 13 may be arranged outside the watertight casing 6. In variant, the filtering device 13 may be arranged inside the watertight casing 6.

[0097] Figure 3 represents schematically a third embodiment of the integrated motor-compressor assembly 1 .

[0098] The same references designate the same elements as previously referenced in the first embodiment of the integrated motor-compressor assembly 1 represented in figures 1 and 2.

[0099] The third embodiment of the integrated motor-compressor assembly 1 differs from the second embodiment of the integrated motorcompressor assembly 1 illustrated in figure 2 in that the integrated motor-compressor assembly 1 compri ses a first pipe 19 connecting a first connection of the electric motor 2 to the gas input 12a of the cooling fan 12 and a second pipe 20 connecting a second connection of the electric motor 2 to the gas input 12a of the cooling fan 12.

[0100] The first connection of the electric motor 2 lies on a first side of the electric motor 2 and the second connection of the electric motor 2 lies on a side of the electric motor 2 opposed to the first side of the electric motor 2.

[0101] The first part of compressed cooling gas heated by the electric motor 2 i s aspirated by the cooling fan 12 through the first and second pipes 19, 20 forming a bilateral cooling.

[0102] The first and second pipes 19, 20 are inside the watertight casing 6 as represented.

[0103] In variant, the first pipe 19 and / or second pipe 20 may be outside the watertight casing 6.

[0104] In another embodiment, the first pipe 19 may be replaced by a channel drilled in at least one wall of the watertight casing 6, the channel connecting the second connection of the electric motor 2 to the gas input 12a of the cooling fan 12.

[0105] A first end of a pipe 21 is connected to the gas input 12a of the cooling fan 12 and the second end of the pipe 21 emerges into the watertight casing 6 so that the cooling fan 12 aspirates compressed cooling gas released inside the watertight casing 6. Figure 4 represents schematically a fourth embodiment of the integrated motor-compressor assembly 1.

[0106] The same references designate the same elements as previously referenced in the first embodiment of the integrated motor-compressor assembly 1 represented in figures 1 and 2.

[0107] The fourth embodiment of the integrated motor-compressor assembly 1 differs from the second embodiment of the integrated motorcompressor assembly 1 illustrated in figure 2 in that the cooling fan 12 is mounted in overhung on the drive shaft 3 between the second compression section 5 and the electric motor 2, the gas diffuser 16 is arranged between the electric motor 2 and the first compression section 4, and the suction device 17 is arranged between the first compression section 4 and the gas diffuser 16 to avoid that unfiltered gas in the first compression section 4 leaks inside the watertight casing 6.

[0108] The buffer gas system 18 is connected to the gas output 12b of the cooling fan 12 and arranged between the gas diffuser 16 and the suction device 17.

[0109] The suction device 17 aspirates gas leaking from the first compression section 4 inside the watertight casing 6 and inj ects the aspirated gas in the gas input 5a of the second compression section 5.

[0110] In the embodiments of the integrated motor-compressor assembly 1 , the cooling gas intended to cool the electric motor 2 and / or the bearings 9, 10 is taken at the gas input of the integrated motorcompressor assembly 1 so that the cooling gas is not compressed by a compression section 4, 5 of the integrated motor-compressor assembly 1.

[0111] The cooling gas is set in motion in the cooling loop 15 by the rotation of the cooling fan 12 to cool components inside the watertight casing 6, for example the electric motor 2 and / or the bearings 9, 10.

[0112] Overhung designates that a component of the integrated motorcompressor assembly such as the cooling fan 12, the first compression section 4 or the second compression section 5 is not located between the first and second bearings 9, 10. The said component i s positioned in overhung in respect with the first or the second bearings 9, 10.

[0113] As the energy consumed by the cooling fan 12 to set the cooling gas in motion in the cooling loop 15 is smaller than the energy consumed to compress the cooling gas in the first compression section 4, the energy consumed by the integrated motor-compressor assembly 1 is reduced compared to an integrated motor-compressor assembly 1 compri sing a cooling loop including a control valve configured to expand gas known from the prior art.

[0114] Further, the reliability of the cooling fan is higher than the reliability of a regulated control valve expanding gas at a predetermined pressure known form the prior art so that the reliability of the integrated motor-compressor assembly 1 is increased.

[0115] Advantageously, the cooling fan 12 aspirating the cooling gas (figures 2, 3 and 4) is more compact than a cooling fan compressing the cooling gas (figure 1 ) so that the integration of the cooling fan 12 configured to aspirate the cooling fan in the integrated motorcompressor assembly 1 is easier.

[0116] Further, it is known that a fan moving a gas heats the said gas. Advantageously, the cooling gas flowing through the cooling fan 12 aspirating the said gas and heated by the cooling fan is delivered at the gas input 7 so that the cooling gas cooling the electric motor 2 and the bearings is cooler that the cooling gas compressed by the cooling fan enhancing the efficiency of the cooling loop.

Claims

CLAIMS1. Integrated motor-compressor assembly ( 1 ) comprising: a gas input (7), a drive shaft (3 ), magnetic bearings (9, 10) supporting the drive shaft (3 ), an electric motor (2) mounted on a drive shaft, a first compression section (4) comprising an axial gas input and in overhung at a first end of the drive shaft and configured to compress a gas flowing at the gas input of the integrated motor-compressor assembly, and a second compression section (5) comprising an axial gas input and in overhung at a second end of the drive shaft, wherein the integrated motor-compressor assembly further comprises a cooling fan ( 12) arranged in overhung and mounted on the drive shaft (3) between one compression section of the first or the second compression sections (4, 5) and the electric motor (2), the cooling fan being configured to circulate a part of the gas taken at the gas input of the integrated motor-compressor assembly in a cooling loop ( 1 1 , 15) of the integrated motorcompressor assembly, the part of the gas being a cooling gas, the cooling loop being configured to cool down the magnetic bearings and an electric motor of the integrated motorcompressor assembly, the cooling fan comprising a casing ( 12e) and a compression wheel ( 12c) arranged in the casing (12e).

2. Integrated motor-compressor assembly according to claim 1 , wherein the cooling fan (12) is mounted between the first compression section (4) and the electric motor (2), the cooling fan (12) being configured to compress the cooling gas to supply the cooling loop ( 1 1 ) of the integrated motor-compressor assembly with the compressed cooling gas.

3. Integrated motor-compressor assembly according to claim 2, further comprising the cooling loop ( 1 1 ) including a filtering device(13), the filtering device being connected to the cooling fan (12) and to the electric motor (2) so that a first part of the compressed cooling gas filtered by the filtering device flows through the electric motor to cool the electric motor.

4. Integrated motor-compressor assembly according to claim 3 , wherein the filtering device ( 13) is further connected to each magnetic bearing so that a second part of the compressed cooling gas filtered by the filtering device flows through the magnetic bearings to cool the magnetic bearings.

5. Integrated motor-compressor assembly according to claim 4, further comprising a watertight casing (6), the drive shaft (3 ), the electric motor (2), the first compression section (4), the second compression section (5), the cooling fan ( 12) and the magnetic bearings (9, 10) being arranged in the watertight casing (6), the cooling loop (1 1 ) further comprising an exhaust duct ( 14) configured to exhaust the first part of the compressed cooling gas, heated by the electric motor (2), released inside the watertight casing and to exhaust the second part of the compressed cooling gas, heated by the magnetic bearings (9, 10), released inside the watertight casing.

6. Integrated motor-compressor assembly according to claim 1 , wherein the cooling fan ( 12) i s configured to aspirate the cooling gas.

7. Integrated motor-compressor assembly according to claim 6, further comprising the cooling loop (15) comprising a filtering device (13) connected to the gas input (7) and to the electric motor (2) so that a first part of the cooling gas filtered by the filtering device flows through the electric motor to cool the electric motor, the cooling gas heated by the electric motor being aspirated by the cooling fan.

8. Integrated motor-compressor assembly according to claim 7, wherein the cooling fan (12) comprises a gas output (12b) configured to deliver the cooling gas aspirated by the cooling fan (12), the integrated motor-compressor further comprising: a watertight casing (6), the drive shaft (3 ), the electric motor (2), the first compression section (4), the second compressionsection (5) and the cooling fan ( 12) being arranged in the watertight casing (6), a suction device ( 17) configured to aspirate gas leaking inside the watertight casing (6) from the compression section of the first or the second compression sections (4, 5) farthest from the cooling fan ( 12) and to inj ect the aspirated gas in a gas input of the first or the second compression section, a gas diffuser ( 16) configured to be fed with a second part of the filtered cooling gas and diffuse the second part of the filtered cooling gas in the watertight casing (6),- the gas diffuser ( 16) being arranged between the electric motor (2) and the compression section of the first or the second compression sections (4, 5) farthest from the cooling fan (12), and the suction device (17) being arranged between the compression section of the first or the second compression sections (4, 5) farthest from the cooling fan (12) and the gas diffuser (16), and a buffer gas system ( 18) connected to the gas output of the cooling fan and arranged between the gas diffuser and the suction device, and configured to diffuse a part of the cooling gas aspirated by the cooling fan.

9. Integrated motor-compressor assembly according to claim 8, wherein the filtering device ( 13) is further connected to each magnetic bearing so that a third part of the filtered cooling gas flows through the magnetic bearings to cool the magnetic bearings, the cooling gas heated by the magnetic bearings being aspirated by the cooling fan.

10. Integrated motor-compressor assembly according to any one of claims 5, 8 and 9, wherein the filtering device ( 13) is arranged outside the watertight casing.

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