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), - 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) at a second end of the drive shaft. The first compression section comprises a cooling fan (12) configured to be driven by the drive shaft to supply a cooling loop (11) of the integrated motor-compressor assembly with a part of the gas taken at the gas input of the integrated motor-compressor assembly, the part of the gas being a cooling gas. Reference: Figure 1

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 expends 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] - a first compression section 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

[0019] - a second compression section at a second end of the drive shaft.

[0020] The first compression section comprises a cooling fan configured to cool the magnetic bearings and an electric motor of the integrated motor-compressor assembly, the cooling fan being configured to be driven by the drive shaft to supply a cooling loop of the integrated motor-compressor assembly with a part of the gas taken at the gas input of the integrated motor-compressor assembly, the part of the gas being a cooling gas.

[0021] Advantageously, the first compression section comprises a radialgas input connected to the gas input of the integrated motorcompressor assembly and a casing, the cooling fan compri sing a fan compression wheel arranged in overhung in the casing at the first end of the drive shaft, the fan compression wheel of the fan being configured to be driven by the drive shaft to compress the cooling gas.

[0022] Preferably, the first compression section comprises a radial gas input connected to the gas input of the integrated motor-compressor assembly and the cooling fan is arranged in overhung at the first end of the drive shaft, the cooling fan comprising a casing including a fan compression wheel and a gas input connected to the radial gas input of the first compression section. Advantageously,

[0023] - the first compression section comprises an axial gas input or a radial gas input connected to the gas input of the integrated motorcompressor assembly, a shroud and a closed impeller in overhung arranged in the shroud with a gap,

[0024] - the closed impeller comprising an intermediary part including a first part and a second part, the first part being connected to the second part and the second part connecting the first part to the drive shaft, the closed impeller further comprising a bladed part arranged on the second part and a cover surrounding the first part and the bladed part, the cover compri sing a cover aperture facing the first part, a fan compression wheel being inserted in the cover aperture and extending outside the closed impeller, a gas supply channel being formed between the first part and the cover and configured to supply the fan compression wheel and the bladed part with gas flowing in the said axial gas input or radial gas input of the first compression section,

[0025] - the shroud comprises a shroud aperture facing the fan compression wheel and configured to be connected with the cooling loop and a fan seal arrangement arranged in the gap on each side of the shroud aperture according to an axial direction of the closed impeller,

[0026] - the shroud aperture of the shroud, the fan seal arrangements and the fan compression wheel forming the cooling fan.

[0027] Advantageously, the first compression section comprises an axial gas input connected to the gas input of the integrated motorcompressor assembly, an impeller in overhung at the first end of the drive shaft and configured to compress the gas flowing in the axial gas input of the first compression section, a casing surrounding partially the impeller with a gap and sealing devices arranged in the gap to form a sealed chamber configured to supply the cooling loop with the cooling gas, the impeller further comprises an ogiva at the free end of the impeller and a channel inside the impeller, the ogiva further comprising an aperture connected to a first end of the channel to supply the channel with the cooling gas, a second end of the channel opening into the sealed chamber, the impeller, the channel and the sealed chamber forming the cooling fan.

[0028] Preferably, the channel extends according to an oblique line relative to a rotation axis of the impeller so that the cooling gas is compressed in the channel .

[0029] Advantageously, the impeller comprises an exducer to compress the cooling gas flowing in the channel, the exducer being arranged in the casing.

[0030] Preferably, the ogiva comprises an inducer.

[0031] Advantageously, the integrated motor-compressor assembly further comprises :

[0032] - an electric motor mounted on the drive shaft configured to drive the drive shaft, and

[0033] - a cooling loop including a filtering device,

[0034] - the filtering device being connected to the cooling fan and to the electric motor so that a first part of a compressed cooling gas, filtered by the filtering device, flows through the electric motor to cool the electric motor.

[0035] Preferably, the filtering device is further connected to each magnetic bearing so that a second part of the filtered cooling gas flows through the magnetic bearings to cool the magnetic bearings

[0036] Preferably, in a more particular embodiment, the second compression section is in overhung at the second end of the drive shaft.

[0037] BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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 :

[0039] [Fig 1 ] illustrates schematically an embodiment of an integrated motor-compressor assembly according to the invention;

[0040] [Fig 2] illustrates schematically a second embodiment of a first compression section of the integrated motor-compressor assembly according to the invention; [Fig 3 ] illustrates schematically a third embodiment of the first compression section according to the invention;

[0041] [Fig 4] illustrates schematically a fourth embodiment of the first compression section according to the invention;

[0042] [Fig 5] illustrates schematically a fifth embodiment of the first compression section according to the invention; and

[0043] [Fig 6] illustrates schematically a sixth embodiment of the first compression section according to the invention.

[0044] DETAILED DESCRIPTION

[0045] Reference is made to Figure 1 which represents schematically a first embodiment of an integrated motor-compressor assembly 1.

[0046] 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.

[0047] The electric motor 2 and the two compression sections 4, 5 are arranged in the watertight casing 6.

[0048] A first compression section 4 is in overhung at a first end of the drive shaft 3 and the second compression section 5 is at the second end of the drive shaft 3.

[0049] Each compression section 4, 5 includes a gas input 4a, 5 a and a gas output 4b, 5b .

[0050] In a first embodiment of the first compression section 4 represented on figure 1 , the gas input 4a is a radial gas input.

[0051] The gas input 5 a of the second compression section 5 i s an axial gas input.

[0052] 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 a gas output 8 of the integrated motor-compressor assembly 1 .

[0053] Each compression section 4, 5 may comprise one compression wheel 4c, 5c. 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.

[0054] The electric motor 2 is intended to drive the compression sections 4, 5 so that the first compression section 4 compresses a gas flowing in the gas input 7 of the integrated motor-compressor assembly 1 and delivers the compressed gas to the gas input 5 a of the second compression 5.

[0055] The electric motor 2 is further intended to drive the second compression section 5 to further compress the compressed gas delivered by the first compression section 4, the second compression section delivering the compressed gas to the gas output 8 of the integrated motor-compressor assembly 1.

[0056] The drive shaft 3 i s supported by two bearings 9, 10 in the watertight casing 6.

[0057] Each bearing 9, 10 comprises a radial bearing and / or an axial bearing.

[0058] Preferably, in a more particular embodiment, the second compression section 5 is in overhung at the second end of the drive shaft 3.

[0059] The bearings 9, 10 may comprise gas bearings or preferably magnetic bearings.

[0060] It is assumed in the following that the bearings 9, 10 are magnetic bearings, each magnetic bearing 9, 10 comprises a radial magnetic bearing and / or an axial magnetic bearing.

[0061] 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.

[0062] The integrated motor-compressor assembly 1 further comprises a cooling loop 1 1 .

[0063] The first compression section 4 further comprises a cooling fan 12 mounted in overhung on the drive shaft to supply the cooling loop 1 1 with a part of the gas taken at the gas input 7 of the integrated motorcompressor assembly 1. 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 integrated motorcompressor assembly .

[0064] The part of the gas taken at the gas input 7 of the integrated motor-compressor assembly 1 is named cooling gas.

[0065] In a first embodiment of the first compression section 4, the first compression section 4 comprises a casing 4e including the compression wheel 4c, the gas input 4a of the first compression section 4, the gas output 4b of the first compression section 4 and the cooling fan 12 including a fan compression wheel 12a.

[0066] The gas input 7 of the first compression section 4 leads to the low-pressure part of the compression wheel 4c of the first compression section 4 and the low-pressure part of the fan compression wheel 12a.

[0067] The low-pressure part of the compression wheel 4c of the first compression section 4 faces the low-pressure part of the fan compression wheel 12a of the cooling fan 12.

[0068] A gas intended to be compressed by a compression wheel enters the low-pressure part of the compression wheel and exits the high- pressure part of the compression wheel . The pressure of the gas in the high-pressure part of the compression wheel is higher than the pressure of the said gas in the low-pressure part of the compression wheel . The casing 4e of the first compression section 4 further comprises a fan gas output 12b exhausting the cooling gas compressed by the fan compression wheel 12a.

[0069] The arrangement of the cooling fan 12 in the casing 4e of the first section 4 simplifies the feeding of the fan compression wheel 12a.

[0070] The cooling loop 1 1 further comprises a filtering device 13 compri sing 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 the magnetic bearings 9, 10. 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.

[0071] 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 the magnetic bearings 9, 10.

[0072] A first part of the compressed cooling gas filtered by the filtering device 13 may flow 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 may flow through the magnetic bearings 9, 10 to cool the magnetic bearings 9, 10.

[0073] The first part of the compressed cooling gas heated by the electric motor 2 and the second part of the compressed cooling gas heated by the magnetic bearings 9, 10 are released inside the watertight casing 6.

[0074] The heated cooling gas released in the watertight casing 6 is evacuated through the gas input 7 of the integrated motor-compressor assembly 1 via the exhaust duct 14.

[0075] The cooling fan 12 may be 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 the bearings 9, 10, and according to the pressure drop in the cooling loop 1 1 .

[0076] As represented, the filtering device 13 may be arranged outside the watertight casing 6.

[0077] In variant, the filtering device 13 may be arranged inside the watertight casing 6.

[0078] Unfiltered gas may include particles likely to damage components inside the watertight casing 6, for example to damage the bearings 9, 10, the electric motor 2. The particles may be corrosion product from process piping, rust, water droplets carried over by process flow or any solid particle in the processed gas flowing in the gas input 7.

[0079] The filtering device 13 i s designed to remove these particles from the gas flowing in the gas input 7 of the integrated motorcompressor assembly 1.

[0080] Figure 2 represents schematically a second embodiment of the first compression section 4.

[0081] The same references designate the same elements as previously referenced in the embodiment of the integrated motor-compressor assembly 1 represented in figure 1.

[0082] Contrary to the first embodiment of the first compression section 4, the cooling fan 12 compri ses a casing 12c independent from the casing 4e of the first compression section 4.

[0083] The cooling fan 12 is arranged in overhung at the first end of the drive shaft 3.

[0084] The low-pressure part of the compression wheel 4c of the first compression section 4 faces the high-pressure part of the fan compression wheel 12a of the cooling fan 12.

[0085] A gas intended to be compressed by a compression wheel enters the low-pressure part of the compression wheel and exits the high- pressure part of the compression wheel . The pressure of the gas in the high-pressure part of the compression wheel is higher than the pressure of the said gas in the low-pressure part of the compression wheel . The cooling fan comprises a gas input 12d connected to the radial gas input 4a of the first compression section 4 and a gas output 12e connected to the input 13 a of the filtering device 13.

[0086] Figure 3 represents schematically a third embodiment of the first compression section 4.

[0087] In thi s embodiment, the first compression section 4 comprises an axial gas input 20 connected to the gas input 7 of the integrated motorcompressor assembly 1 and a gas output 21 connected to the gas input 5a of the second compression section 5. The first compression section 4 comprises a shroud 22 and a closed impeller 23 in overhung arranged in the shroud with a gap Gp.

[0088] The closed impeller 23 is connected to the drive shaft 3 to compress the gas flowing in the axial gas input 20.

[0089] The closed impeller 23 comprises an ogiva 24 at the free end of the closed impeller 23 and an intermediary part 25 connecting the ogiva 24 to the drive shaft 3.

[0090] The ogiva 24 and the intermediary part 25 may be a single piece.

[0091] The intermediary part 25 comprises a first part 26 and a second part 27, the first part 26 connecting the ogiva 24 to the second part 27 and the second part 27 connecting the first part 26 to the drive shaft 3.

[0092] The first part 26 comprises a first end 26a connected to the ogiva 24 and a second end 26b opposed to the first end 26a.

[0093] The second end 26b of the first part 26 is connected to a first end 27a of the second part 27.

[0094] The second part 27 comprises a second end 27b opposed to the first end 27a of the second part 27 and connected to the drive shaft 3.

[0095] The closed impeller 23 further compri ses a bladed part 28 arranged on the second part 27 and a cover 29 surrounding the first part 26 and the bladed part 28.

[0096] The bladed part 28 comprises vanes to compress gas.

[0097] As the bladed part 28 is not arranged on the first part 26, no vanes are fixed on the first part 26 so that a gas supply channel 30 i s formed between the first part 26 and the cover 29.

[0098] The cover 29 compri ses a cover aperture 3 1 facing the first part 26.

[0099] A fan compression wheel 32 i s inserted in the cover aperture 3 1 and extending outside the closed impeller 23.

[0100] The fan compression wheel 32 may be integrated in the cover 29, the cover 29 and the fan compression wheel 32 being for example moulded.

[0101] In variant, the compression wheel 32 is inserted in the cover 29, for example the blades of the compression wheel 32 are screwed or welded or brazed on the cover 29. The shroud 22 comprises a shroud aperture 33 facing the compression wheel 32 of the closed impeller 23 and connected to the input 13 a of the filtering device 13 through a duct 34.

[0102] A fan seal arrangement 35 is arranged in the gap Gp on each side of the shroud aperture 33 according to an axial direction of the closed impeller 23 .

[0103] Each fan seal arrangement 35 may comprise a labyrinth.

[0104] The shroud aperture 33 of the shroud 22, the fan seal arrangements 35 and the fan compression wheel 32 form the cooling fan.

[0105] The gas supply channel 30 supplies the bladed part 28 and the fan compression wheel 32 with gas flowing the axial gas input 20 of the first compression section 4.

[0106] When the drive shaft 3 drives the closed impeller 23 , the fan compression wheel 32 compresses a first part of the gas (cooling gas) supplied by the supply channel 30, the part of the compressed gas (cooling gas) flowing in the input 13 a of the filtering device 13 through the shroud aperture 33. The bladed part 29 compresses a second part of the gas supplied by the supply channel 30, the second part being equal to the gas supplied by the supply channel 30 minus the first part of the gas, the second part of gas compressed by the bladed part 29 evacuating the first compression section 4 through the gas output 21.

[0107] The first compression section 4 further comprises a sealing device 36 to avoid that compressed gas leaks inside the watertight casing 6, the sealing device 36 being arranged between the shroud 22 and the drive shaft 3. The sealing device 36 may comprise a labyrinth.

[0108] Figure 4 represents schematically a fourth embodiment of the first compression section 4.

[0109] In thi s embodiment, the first compression section 4 comprises an axial gas input 40 connected to the gas input 7 of the integrated motorcompressor assembly 1 and a gas output 41 connected to the gas input 5a of the second compression section 5.

[0110] The first compression section 4 compri ses a shroud 42 and an impeller 43 in overhung at the first end of the drive shaft 3.

[0111] The impeller 43 is arranged in the shroud 42. A casing 44 surrounds partially the impeller 43 with a gap.

[0112] Sealing devices 45 are arranged in the gap to form a sealed chamber 44a.

[0113] The casing 44 further comprises an output 46 connected to the input 13 a of the filtering device 13.

[0114] Each sealing device 45 may comprise a labyrinth.

[0115] The impeller 43 further compri ses an ogiva 47 at the free end of the impeller 43 and a channel 49 inside the impeller 43.

[0116] As represented, the ogiva 47 may be conical .

[0117] An aperture 48 is connected to a first end of the channel 49 and a second end of the channel 49 opens into the sealed chamber 44a.

[0118] A part of the gas flowing in the first compression section 4 flows in the channel 49, the part of the gas flowing in the channel 49 being the cooling gas.

[0119] The impeller 43 , the sealed chamber 44a and the channel 49 form the cooling fan.

[0120] The impeller 43 may further comprise an exducer 50 arranged in the casing 44 to compress the cooling gas flowing in the channel 49.

[0121] When the drive shaft 3 drives the impeller 43 , the impeller 43 compresses the gas and the cooling gas flows through the channel 49 in the sealed chamber 44a. The exducer 50 driven by the drive shaft 3 compresses the cooling gas in the sealed chamber 44a.

[0122] The compressed cooling gas flows through the output 46 of the sealed chamber 44a to supply the filtering device 13.

[0123] Figure 5 represents schematically a fifth embodiment of the first compression section 4.

[0124] In thi s embodiment, the first compression section 4 comprises an axial gas input 55 connected to the gas input 7 of the integrated motorcompressor assembly 1 and a gas output 56 connected to the gas input 5a of the second compression section 5.

[0125] The first compression section 4 compri ses a shroud 57 and an impeller 58 in overhung at the first end of the drive shaft 3.

[0126] The impeller 58 is arranged in the shroud 57.

[0127] A casing 59 surrounds partially the impeller 58 with a gap. Sealing devices 60 are arranged in the gap to form a sealed chamber 59a.

[0128] The casing 59 further comprises an output 61 connected to the input 13 a of the filtering device 13.

[0129] Each sealing device 60 may comprise a labyrinth.

[0130] The impeller 58 further compri ses an ogiva 62 at the free end of the impeller and a channel 63 inside the impeller.

[0131] An aperture 64 is connected to a first end of the channel 63 and a second end of the channel 63 opens into the sealed chamber 59a.

[0132] The impeller 58, the sealed chamber 59a and the channel 63 form the cooling fan.

[0133] The ogiva 62 may comprise an inducer 62a.

[0134] The channel 63 extends according to an oblique line relative to a rotation axis of the impeller 58 so that the cooling gas is compressed in the channel 63 .

[0135] In another variant, the ogiva 62 does not comprise the inducer 62a and may be conical .

[0136] The inducer 62a reduces the pressure drop in the first compression section 4 to save energy to compress the gas flowing in the axial gas input 55.

[0137] The first compression section 4 may comprise the exducer 50 as represented on figure 4 in the fourth embodiment of the first compression section 4.

[0138] Of course, the impeller 43 in the fourth embodiment of the first compression section 4 may comprise the inducer 62a.

[0139] A part of the gas flowing in the first compression section 4 flows in the channel 63 , the part of the gas flowing in the channel 63 being the cooling gas.

[0140] When the drive shaft 3 drives the impeller 58, the impeller 58 compresses the gas and the cooling gas flows through the channel 63 in the sealed chamber 59a. The inducer 62a driven by the drive shaft 3 compresses the cooling gas flowing in the channel 63 so that the cooling gas is compressed before entering in the channel 63. The orientation of the channel 63 according to an oblique line permits to further compress the cooling gas entering the channel 63.

[0141] The compressed cooling gas flows through the output 61 of the sealed chamber 59a to supply the filtering device 13.

[0142] The sealing devices 4d, 5d, 36, 45 , 60 may compri se labyrinths and may further comprise intermediate connection lines (not represented) to the gas input 7 and to the gas output 13b . Arrangement of the labyrinths and different connection lines is made so that no unfiltered gas can enter bearing and compressor elements, such as bearing 9, 10 and electric motor 2.

[0143] Each connection line may comprise a pipe.

[0144] The sealing devices 4d, 5d, 36, 45, 60 avoid that that unfiltered gas flows inside the internal bearings 9, 10 and the electric motor 2.

[0145] Overhung designates that a component of the integrated motorcompressor assembly such as the fan compression wheel 12a, the cooling fan 12, the impeller 43 , 58, the closed impeller 23 , the first compression section 4 or the second compression section 5 is not located between the first and second bearings 9, 10.

[0146] The said component i s positioned in overhung in respect with the first or the second bearings 9, 10.

[0147] In the first and second embodiments of the first compression section 4, the cooling gas intended to cool the electric motor 2 and 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.

[0148] The cooling gas is supplied in the cooling loop by the rotation of the cooling fan to cool components inside the watertight casing 6, for example the electric motor 2 and the bearings 9, 10.

[0149] As the energy consumed by the cooling fan to supply the cooling loop with cooling gas is smaller than the energy consumed to compress the cooling gas in the first compression section, the energy consumed by the integrated motor-compressor assembly 1 is reduced compared to an integrated motor-compressor assembly 1 comprising a cooling loop known from the prior art.

[0150] Further, in the first to fifth embodiments of the first compression section 4, the cooling fan is integrated in the first compression section and the cooling loop does not comprise a control valve configured to expand compressed cooling gas (energy destruction).

[0151] As no energy i s destroyed by the expansion of compressed cooling gas, the efficiency of the integrated motor-compressor assembly 1 is increased compared to a motor-compressor assembly comprising a cooling loop including a control valve known from the prior art.

[0152] 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.

[0153] Figure 6 represents schematically a sixth embodiment of the first compression section 4.

[0154] The sixth embodiment of the first compression section 4 differs from the third embodiment of the first compression section in figure 3 in that the first compression section 4 comprises a radial gas input 70 connected to the gas input 7 of the integrated motor-compressor assembly 1 and a shroud 71.

[0155] The same references designate the same elements as references in figure 3 in the third embodiment of the integrated motor-compressor assembly 1 represented in figure 3.

[0156] The closed impeller 23 is arranged in overhung in the shroud with a gap Gp l .

[0157] The shroud 71 comprises a shroud aperture 72 facing the compression wheel 32 of the closed impeller 23 and connected to the input 13 a of the filtering device 13 through a duct 34.

[0158] A fan seal arrangement 73 is arranged in the gap Gp l on each side of the shroud aperture 72 according to an axial direction of the closed impeller 23 .

[0159] Each fan seal arrangement 73 may comprise a labyrinth. The shroud aperture 72 of the shroud 71 , the fan seal arrangements 35 and the fan compression wheel 32 form the cooling fan.

[0160] When the drive shaft 3 drives the closed impeller 23 , the fan compression wheel 32 compresses a first part of the gas (cooling gas) supplied by the supply channel 30, the part of the compressed gas (cooling gas) flowing in the input 13 a of the filtering device 13 through the shroud aperture 72. The bladed part 29 compresses a second part of the gas supplied by the supply channel 30, the second part being equal to the gas supplied by the supply channel 30 minus the first part of the gas, the second part of gas compressed by the bladed part 29 evacuating the first compression section 4 through the gas output 21.

[0161] The first compression section 4 further comprises a sealing device 74 to avoid that compressed gas leaks inside the watertight casing 6, the sealing device 74 being arranged between the shroud 71 and the drive shaft 3. The sealing device 74 may comprise a labyrinth.

[0162] In the embodiments of the first compression section, the cooling fan supplying the cooling loop of the integrated motor-compressor assembly compresses only the cooling gas (part of gas taken at the gas input of the integrated motor-compressor assembly) which enhances the rotodynamic of the integrated motor-compressor assembly .

[0163] Further, the cooling fan does not interact with the entire flow of gas flowing through the gas input of the integrated motor-compressor assembly reducing the energy consumed by the cooling fan compressing only the cooling gas.

[0164] In the third and sixth embodiments of the first compression section illustrated in figures 3 and 6, the cooling fan is integrated in the shroud to minimize overhang to avoid having a separated fan in long overhang to provide the cooling gas. The arrangement of the cooling fan in the shroud is compatible with both an axial gas inlet and a radial gas inlet of the first compression section.

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 ), 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) at a second end of the drive shaft, characterized in that the first compression section comprises a cooling fan (12) configured to cool the magnetic bearings (9, 10) and an electric motor (2) of the integrated motor-compressor assembly ( 1 ), the cooling fan ( 12) being configured to be driven by the drive shaft to supply a cooling loop (1 1 ) of the integrated motor-compressor assembly with a part of the gas taken at the gas input of the integrated motor-compressor assembly, the part of the gas being a cooling gas.

2. Integrated motor-compressor assembly according to claim 1 , wherein the first compression section (4) comprises a radial gas input (4a) connected to the gas input of the integrated motor-compressor assembly and a casing (4e), the cooling fan ( 12) comprising a fan compression wheel ( 12a) arranged in overhung in the casing at the first end of the drive shaft (3), the fan compression wheel of the fan being configured to be driven by the drive shaft to compress the cooling gas.

3. Integrated motor-compressor assembly according to claim 1 , wherein the first compression section (4) comprises a radial gas input (4a) connected to the gas input of the integrated motor-compressor assembly and the cooling fan ( 12) i s arranged in overhung at the first end of the drive shaft (3 ), the cooling fan comprising a casing ( 12c) including a fan compression wheel ( 12a) and a gas input ( 12d) connected to the radial gas input (4a) of the first compression section.

4. Integrated motor-compressor assembly according to claim 1 , wherein:- the first compression section (4) comprises an axial gas input (20) or a radial gas input (70) connected to the gas input of the integrated motor-compressor assembly, a shroud (22) and a closed impeller (23) in overhung arranged in the shroud with a gap (Gp),- the closed impeller (23) comprising an intermediary part (25) including a first part (26) and a second part (27), the first part (26) being connected to the second part (27) and the second part (27) connecting the first part (26) to the drive shaft (3), the closed impeller (23) further comprising a bladed part (28) arranged on the second part (27) and a cover (29) surrounding the first part (26) and the bladed part (28), the cover (29) comprising a cover aperture (3 1 ) facing the first part, a fan compression wheel (32) being inserted in the cover aperture and extending outside the closed impeller (23 ), a gas supply channel (30) being formed between the first part and the cover and configured to supply the fan compression wheel and the bladed part with gas flowing in the said axial gas input or radial gas input of the first compression section,- the shroud (22) comprising a shroud aperture (33 ) facing the fan compression wheel (32) and configured to be connected with the cooling loop ( 1 1 ) and a fan seal arrangement (35) arranged in the gap on each side of the shroud aperture according to an axial direction of the closed impeller,- the shroud aperture (33) of the shroud (22), the fan seal arrangements (35) and the fan compression wheel (32) forming the cooling fan.

5. Integrated motor-compressor assembly according to claim 1 , wherein the first compression section (4) comprises an axial gas input (40, 55) connected to the gas input of the integrated motor-compressor assembly, an impeller (43 , 58) in overhung at the first end of the drive shaft (3) and configured to compress the gas flowing in the axial gasinput of the first compression section, a casing (44, 59) surrounding partially the impeller with a gap and sealing devices (45, 60) arranged in the gap to form a sealed chamber (44a, 59a) configured to supply the cooling loop ( 1 1 ) with the cooling gas, the impeller further comprises an ogiva (47, 62) at the free end of the impeller and a channel (49, 63) inside the impeller, the ogiva further comprising an aperture (48, 64) connected to a first end of the channel to supply the channel with the cooling gas, a second end of the channel opening into the sealed chamber, the impeller, the channel and the sealed chamber forming the cooling fan.

6. Integrated motor-compressor assembly according to claim 5, wherein the channel (63 ) extends according to an oblique line relative to a rotation axis of the impeller (58) so that the cooling gas i s compressed in the channel .

7. Integrated motor-compressor assembly according to claim 5 or 6, wherein the impeller (43 ) comprises an exducer (50) to compress the cooling gas flowing in the channel, the exducer being arranged in the casing (44).

8. Integrated motor-compressor assembly according to any one of claims 5 to 7, wherein the ogiva (62) comprises an inducer (62a).

9. Integrated motor-compressor assembly according to any one of claims 1 to 8, further compri sing: an electric motor mounted on the drive shaft configured to drive the drive shaft, and a 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 a compressed cooling gas, filtered by the filtering device, flows through the electric motor to cool the electric motor.

10. Integrated motor-compressor assembly according to claim 9, wherein, the filtering device (13) is further connected to each magnetic bearing so that a second part of the filtered cooling gas flows through the magnetic bearings to cool the magnetic bearings.1 1 . Integrated motor-compressor assembly according to any one of the preceding claims, wherein, the second compression section (5) i s in overhung at the second end of the drive shaft (3 ).

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