WO2015034641A1

WO2015034641A1 - Motor cooling system manifold

Info

Publication number: WO2015034641A1
Application number: PCT/US2014/051048
Authority: WO
Inventors: William C. Maier
Original assignee: Dresser-Rand Company
Priority date: 2013-09-03
Filing date: 2014-08-14
Publication date: 2015-03-12
Also published as: US20150064026A1; US9777746B2; EP3042079A4; EP3042079A1

Abstract

A cooling system for a motor-compressor and a method for cooling the motor-compressor are provided. The cooling system may include a discharge assembly having a hub portion disposed radially outward of a rotary shaft of the motor-compressor. A plurality of arms may be fluidly coupled with and may extend generally tangential from the hub portion of the discharge assembly. The hub portion may define an annular volume fluidly coupled with the plurality of arms. The cooling system may also include a blower impeller disposed in the annular volume and coupled with the rotary shaft. The blower impeller may be configured to rotate with the rotary shaft and draw a cooling fluid into the discharge assembly.

Description

Motor Cooling System Manifold

Cross -Reference to Related Applications

[0001] This application claims priority to U .S. Utility Patent Application having Serial No. 1 4/456,089, which was filed August 1 1 , 2014, and U.S. Provisional Patent Application having Serial No. 61 /873,004, which was filed September 3, 201 3. These priority applications are hereby incorporated by reference in their entirety into the present application to the extent consistent with the present application.

Background

[0002] Conventional compact motor-compressors that incorporate compressors directly coupled with high-speed electric motors have been developed and may often be utilized in a myriad of industrial processes (e.g., petroleum refineries, offshore oil production platforms, and subsea process control systems) to compress process fluids. The compact motor-compressors may combine the high-speed electric motors with the compressors, such as a centrifugal compressor, in a single, hermetically-sealed housing. Through shared or coupled rotary shafts supported by a bearing system, the motors may drive or rotate the compressors to thereby compress the process fluids.

[0003] As the motors drive the compressors, heat may be generated by electrical systems configured to deliver electrical energy to stators of the motors. Additional heat may also be generated through windage friction resulting from the rotating components operating in the pressurized process fluids. Improper management of the heat may reduce operational efficiencies and may ultimately result in damage to the compact motor- compressors and/or components thereof (e.g., insulation of the stators). Additionally, increased temperatures resulting from the improper management of the heat may cause the bearing system to fail, which may cause the rotary shafts supported by the bearing system to fall or drop onto adjacent mechanical surface. Static and dynamic radial and thrust forces acting on the falling rotary shafts upon failure of the bearing system may cause substantial damage to the rotary shafts and/or surrounding components.

[0004] In view of the foregoing, some conventional compact motor-compressors may often utilize external pressurization systems driven separately from the motor- compressors to manage the heat. The external pressurization systems may circulate a separate cooling fluid (e.g., air) in a cooling circuit with an external fan or blower driven independently from the motor-compressors. Failure of the external pressurization systems, however, may result in overheating and potential catastrophic failure. For example, the motor-compressors may continue to operate and generate heat upon failure of the separately driven external pressurization systems, thereby resulting in the overheating of the motor-compressors.

[0005] What is needed, then, is an improved cooling system and method for cooling the motor-compressor and/or components thereof capable of operating concurrently with the motor-compressor.

Summary

[0006] Embodiments of the disclosure may provide a cooling system for a motor- compressor. The cooling system may include a discharge assembly having a hub portion disposed radially outward of a rotary shaft of the motor-compressor. A plurality of arms may be fluidly coupled with and may extend generally tangential from the hub portion of the discharge assembly. The hub portion may define an annular volume fluidly coupled with the plurality of arms. The cooling system may also include a blower impeller disposed in the annular volume and coupled with the rotary shaft. The blower impeller may be configured to rotate with the rotary shaft and draw a cooling fluid into the discharge assembly.

[0007] Embodiments of the disclosure may also provide a motor-compressor. The motor- compressor may include a housing having a motor end and a compressor end. The housing may define a plurality of internal cooling passages of the motor-compressor. A motor may be coupled with a rotary shaft and in fluid communication with at least one of the plurality of internal cooling passages of the motor-compressor. Radial bearings may be disposed proximal each end portion of the rotary shaft and may be in fluid communication with at least one of the plurality of internal cooling passages. The motor- compressor may also include a discharge assembly having a hub portion disposed radially outward of the rotary shaft. A plurality of arms may be fluidly coupled with the hub portion and may extend outward from the hub portion of the discharge assembly. The hub portion may define an annular volume fluidly coupled with the plurality of arms. A blower impeller may be disposed in the annular volume of the hub portion and coupled with the rotary shaft. The blower impeller may be configured to rotate with the rotary shaft and draw a cooling fluid into the discharge assembly.

[0008] Embodiments of the disclosure may further provide a method for cooling a motor- compressor. The method may include supporting each end portion of a rotary shaft in a housing of the motor-compressor with radial bearings. The housing of the motor- compressor may define a plurality of internal cooling passages, and at least one of the plurality of internal cooling passages may be in fluid communication with at least one of the radial bearings. The method may also include rotating the rotary shaft with a motor coupled therewith, and driving a blower impeller coupled with the rotary shaft. The method may also include directing a cooling fluid to a discharge assembly disposed radially outward of the rotary shaft. The discharge assembly may at least partially define an annular volume in a hub portion of the discharge assembly. The method may further include discharging the cooling fluid from the discharge assembly to the plurality of internal cooling passages via a plurality of arms extending outward from the hub portion of the discharge assembly to thereby cool the motor-compressor.

Brief Description of the Drawings

[0009] The present disclosure is best understood from the following detailed description when read with the accompanying Figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

[0010] Figure 1 illustrates a cross-sectional, schematic view of a motor-compressor, according to one or more embodiments disclosed.

[0011] Figure 2A illustrates a cross-sectional, perspective view of a motor portion of another motor-compressor, according to one or more embodiments disclosed. [0012] Figure 2B illustrates an enlarged view of the portion of the motor-compressor indicated by the box labeled "2B" of Figure 2A, according to one or more embodiments disclosed.

[0013] Figure 2C illustrates a perspective view of the blower assembly of the motor- compressor of Figures 2A and 2B, according to one or more embodiments disclosed.

[0014] Figure 2D illustrates a perspective view of the blower assembly of the motor- compressor of Figures 2A and 2B having the cover plate removed, according to one or more embodiments disclosed.

[0015] Figure 3 is a flowchart of a method for cooling a motor-compressor, according to one or more embodiments disclosed.

Detailed Description

[0016] It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the present disclosure; however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention. Additionally, the present disclosure may repeat reference numerals and/or letters in the various exemplary embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various exemplary embodiments and/or configurations discussed in the various Figures. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Finally, the exemplary embodiments presented below may be combined in any combination of ways, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure. [0017] Additionally, certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, various entities may refer to the same component by different names, and as such, the naming convention for the elements described herein is not intended to limit the scope of the invention, unless otherwise specifically defined herein. Further, the naming convention used herein is not intended to distinguish between components that differ in name but not function. Further, in the following discussion and in the claims, the terms "including" and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to." All numerical values in this disclosure may be exact or approximate values unless otherwise specifically stated. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope. Furthermore, as it is used in the claims or specification, the term "or" is intended to encompass both exclusive and inclusive cases, i.e., "A or B" is intended to be synonymous with "at least one of A and B," unless otherwise expressly specified herein.

[0018] Figure 1 illustrates a cross-sectional, schematic view of an exemplary motor- compressor 1 00 having an exemplary cooling system , according to one or more embodiments. In at least one embodiment, the motor-compressor 100 may include a motor 1 02, a compressor 1 04, and an integrated separator 1 06 coupled with one another via a rotary shaft 1 08. In another embodiment, the integrated separator 1 06 may be omitted from the motor-compressor 100. The motor 102, the compressor 104, and/or the integrated separator 1 06 may each be disposed or positioned within a housing 1 10 having a first end, or compressor end 1 12, and a second end, or motor end 1 1 4. In at least one embodiment, the housing 1 1 0 may include a compressor portion 1 1 3 and a motor portion 1 15 configured to hermetically seal the motor 102, the compressor 1 04, and/or the integrated separator 106. For example, the motor 102 may be disposed in the motor portion 1 15 of the housing 1 10, and the compressor 1 04 may be disposed in the compressor portion 1 13 of the housing 1 10.

[0019] The rotary shaft 1 08 may include a motor section 1 1 6 and a driven section 1 18, and may extend substantially from the compressor end 1 1 2 to the motor end 1 1 4 of the housing 1 10. The motor section 1 16 of the rotary shaft 108 may be coupled with or otherwise driven by the motor 102. The driven section 1 1 8 of the rotary shaft 108 may be coupled with the compressor 104 and/or the integrated separator 106. The motor section 1 16 and the driven section 1 18 may be coupled with one another via a coupling 1 20, such as a flexible or a rigid coupling. The coupling 120 may be disposed within a cavity 122 defined within the housing 1 10. Accordingly, the motor 1 02 may rotate the motor section 1 16, which may rotate the driven section 1 18 coupled therewith via the coupling 120.

[0020] In at least one embodiment, the integrated separator 106 may be configured to separate and/or remove high-density components (e.g., liquids and/or solids) from low- density components (e.g., liquids and/or gases) contained within a process fluid introduced thereto. For example, the process fluid may be introduced to the integrated separator 106 via an inlet 144 of the motor-compressor 100, and the integrated separator 1 06 may remove the high-density components contained therein. The high-density components removed from the process fluid may be discharged from the integrated separator 1 06 via a discharge line 1 38 to thereby provide a relatively dry process fluid that may be introduced to the compressor 1 04. In at least one embodiment, the process fluid may be a multiphase fluid and the high-density component may be a liquid. Accordingly, the integrated separator 106 may separate the liquid from the multiphase fluid and discharge the liquid via the discharge line 1 38. The discharged liquid from the discharge line 1 38 may accumulate in a collection vessel (not shown) and may be subsequently pumped or directed back into the process fluid at a pipeline location downstream of the compressor 104.

[0021] In at least one embodiment, the process fluid introduced into the motor-compressor 1 00 via the inlet 144 may include, but is not limited to, a hydrocarbon gas, such as natural gas or methane, which may be derived from a production field or via a pressurized pipeline. The process fluid may also include, but is not limited to, air, carbon dioxide, nitrogen, ethane, propane, or any combination thereof.

[0022] In at least one embodiment, the compressor 104 may be a multistage centrifugal compressor having one or more compressor stage impellers 1 36 (three are shown). It may be appreciated, however, that any number of impellers 1 36 may be utilized without departing from the scope of the disclosure. The compressor 104 may be configured to receive the dry process fluid from the integrated separator 106 and compress the dry process fluid through the impellers 1 36 to thereby provide a compressed or pressurized process fluid. The pressurized process fluid may then be directed or discharged via a process discharge 137 defined in the housing 1 10 of the motor-compressor 100.

[0023] In at least one embodiment, the motor 1 02 may be an electric motor, such as a permanent magnet motor, and may include a stator 1 32 and a rotor 1 34. It may be appreciated, however, that additional embodiments may employ other types of electric motors including, but not limited to, synchronous motors, induction motors, brushed DC motors, or the like. In at least one embodiment, the motor 102 may include a variable frequency drive configured to drive the motor 102 at varying rates or speeds.

[0024] In at least one embodiment, the motor-compressor 100 may include one or more radial bearings 1 24 (four radial bearings are shown) directly or indirectly supported by the housing 1 1 0 and configured to support the rotary shaft 108. For example, as illustrated in Figure 1 , the radial bearings 124 may support the motor section 1 16 and the driven section 1 18 of the rotary shaft 108 at each end portion thereof. Illustrative radial bearings 1 24 may include magnetic bearings, such as active or passive magnetic bearings, or the like. In at least one embodiment, one or more axial thrust bearings 1 26 may be coupled with the rotary shaft 1 08 to at least partially support and/or counteract thrust loads or forces generated by the compressor 1 04. For example, a pressure differential may be provided by the rise in pressure generated from the compressor 1 04, which may provide the compressor 104 with a net thrust or load in the direction of an inlet thereof. The axial thrust bearings 126 may be coupled with the rotary shaft 1 08 at or proximal the compressor end 1 12 of the housing 1 1 0 to at least partially support and/or counteract the net thrust from the compressor 104. In at least one embodiment, a balance piston 1 28 having a balance piston seal 130 may be coupled with the rotary shaft 108 between the motor 102 and the compressor 104 and configured to at least partially counteract the net thrust or load applied thereto from the compressor 104. For example, the balance piston 1 28 may be coupled with the rotary shaft 1 08 near or proximal the last impeller 136 of the compressor 104 to at least partially counteract the net thrust applied thereto.

[0025] In at least one embodiment, the motor-compressor 1 00 may further include one or more buffer seals 140 (two are shown) configured to extend operable lifetimes of the radial bearings 1 24, the axial bearing 1 26, the motor 102, or any combination thereof. For example, the operable lifetimes of the radial bearings 124, the axial bearing 1 26, and/or the motor 1 02 may be extended by using the "clean" or dry process fluid, and the buffe r seals 1 40 may be configured to prevent the "dirty" or multiphase process fluid from being directed or "leaked" to the radial bearings 1 24, the axial bearing 1 26, and/or the motor 1 02. In at least one embodiment, the buffer seals 140 may be radial seals disposed or positioned at or near the end portions of the driven section 1 1 8 of the rotary shaft 1 08. For example, as illustrated in Figure 1 , the buffer seals 1 40 may be disposed inboard of the radial bearings 1 24 at the end portions of the driven section 1 18 of the rotary shaft 1 08. The buffer seals 140 may be dry gas seals and/or carbon ring seals and may be configured to receive a flow of a pressurized seal gas via lines 142. In addition to, or in substitution of the carbon ring seals, the buffer seals 140 may also be or include brush seals or labyrinth seals.

[0026] In at least one embodiment, the pressurized seal gas directed to the buffer seals 1 40 via lines 1 42 may be the pressurized process fluid from the compressor 104. For example, the pressurized process fluid discharged from the compressor 1 04 via the process discharge 1 37 may be subsequently filtered and directed to the buffer seals 1 40 via lines 142. The pressurized seal gas directed to the buffer seals 140 may include, but is not limited to, dry or clean hydrocarbon gases, hydrogen, inert gases, or any combination thereof. Illustrative inert gases may include, but are not limited to, helium, nitrogen, carbon dioxide, or the like. The pressurized seal gas directed to the buffer seals 1 40 may provide a pressure differential to prevent the process fluid (e.g., wet process fluid) from leaking across the buffer seals 140 to portions of the housing 1 1 0 where the radial bearings 1 24, the axial bearing 1 26, and/or the motor 102 may be disposed.

[0027] In exemplary operation of the motor-compressor 1 00, the motor 1 02 may rotate the rotary shaft 108 to drive the compressor 1 04 and the integrated separator 1 06 coupled therewith. The process fluid may be introduced into the motor-compressor 100 via the inlet 1 44 defined in the housing 1 10. The integrated separator 106 may receive the process fluid via the inlet 144 and separate at least a portion of the high-density components (e.g., liquid) therefrom to provide the substantially dry process fluid. The high-density components separated from the process fluid may be removed or discharged via the discharge line 1 38, and the remaining dry process fluid may be directed to the compressor 104. The compressor 1 04 may receive the dry process fluid from the integrated separator 106 and compress the dry process fluid through the impellers 136 thereof to produce the pressurized process fluid. The pressurized process fluid may then be discharged via the process discharge 137.

[0028] In at least one embodiment, the motor-compressor 100 may include a blower assembly 1 50 configured to regulate a temperature of the motor 102 and/or the bearings 1 24, 126 thereof. As further described herein, the blower assembly 150 may regulate the temperature of the motor 1 02 and/or the bearings 124, 126 by flowing or circulating a cooling fluid through a cooling circuit. In at least one embodiment, the blower assembly 1 50 may be at least partially disposed within the housing 1 1 0 of the motor-compressor 1 00. For example, as illustrated in Figure 1 , the blower assembly 150 may be disposed within the motor portion 1 1 5 of the housing 1 1 0. In another embodiment, the blower assembly 1 50 may be coupled with the motor end 1 14 or the compressor end 1 1 2 of the housing 1 1 0. For example, the blower assembly 1 50 may include a bolt-on casing or a blower casing (not shown) coupled with the motor end 1 1 4 of the housing 1 1 0. The blower casing may be bolted directly to the motor end 1 1 4 of the housing 1 1 0 via an existing bolt pattern used to hermetically-seal the motor 102 within the housing 1 1 0. In another example, the blower casing of the blower assembly 1 50 may be coupled or otherwise attached to the housing 1 10 via any other manner known in the art, including, but not limited to, welding, brazing, adhesives, riveting, or any combination thereof. In another embodiment, the blower casing of the blower assembly 150 may be integrally formed with the compressor end 1 1 2 or the motor end 1 14 of the housing 1 1 0.

[0029] As illustrated in Figure 1 , the blower assembly 1 50 may include at least one impeller, such as a blower impeller 1 52, coupled with the rotary shaft 1 08. For example, the blower impeller 152 may be coupled with an end portion of the rotary shaft 1 08 near or proximal the motor end 1 1 4 of the housing 1 1 0. In at least one embodiment, the blower impeller 152 may be a centrifugal impeller and may be driven or rotated by the rotary shaft 1 08 coupled therewith. The rotation of the blower impeller 152 (e.g., centrifugal impeller) may generate a pressure differential (e.g., head pressure) to draw the cooling fluid into the blower assembly 150 via an inlet 1 51 defined in the motor end 1 1 4 of the housing 1 10. [0030] As previously discussed, the motor 102 may have a variable frequency drive configured to drive the motor 1 02 at varying speeds. As such, the pressure differential generated by the blower impeller 1 52 may be determined, at least in part, by the rate or speed in which the rotary shaft 1 08 and/or the motor 1 02 may be operated. In at least one embodiment, the blower impeller 1 52 may be sized or designed to provide the minimum differential pressure necessary to circulate the cooling fluid through the cooling circuit. For example, the blower impeller 152 may be configured to provide the minimum differential pressure when the rotary shaft 1 08 and/or the motor 1 02 may be operating at a low speed (e.g., during startup), when the rotary shaft 1 08 and/or the motor 1 02 may be ramping, and/or when the rotary shaft 1 08 and/or the motor 1 02 may be operating at full speed.

[0031] As illustrated in Figure 1 , the blower assembly 1 50 may include a discharge assembly 1 54 disposed radially outward of the rotary shaft 108. The discharge assembly 1 54 may include a hub portion 1 55 disposed radially outward of the rotary shaft 1 08 and one or more arms (two are shown 1 56) at least partially extending radially outward from the hub portion 155. In at least one embodiment, the blower impeller 1 52 may be at least partially disposed in the hub portion 1 55 and may rotate therein relative to the discharge assembly 154, which may be generally stationary. The arms 1 56 may be in fluid communication with the blower impeller 1 52 and configured to receive the cooling fluid from the blower impeller 152. The arms 1 56 may receive the cooling fluid from the blower impeller 1 52 and direct the cooling fluid to one or more distribution tubes (four are shown 1 61 , 162, 1 63, 164) disposed radially outward of the blower impeller 1 52. For example, the arms 156 of the discharge assembly 1 54 may provide one or more flow passages 236 (see Figure 2D) between the blower impeller 152 disposed in the hub portion 155 and the distribution tubes 1 61 , 1 62, 1 63, 1 64.

[0032] In at least one embodiment, the distribution tubes 161 , 1 62, 1 63, 1 64 may be configured to receive the cooling fluid from the arms 1 56 and direct the cooling fluid to one or more portions of the motor-compressor 1 00. For example, the distribution tubes 1 61 , 1 62, 1 63, 1 64 may receive the cooling fluid from the arms 156 of the blower assembly 1 50 and direct the cooling fluid to the motor 102 and/or the bearings 124, 1 26 to thereby regulate the temperatures thereof. The distribution tubes 1 61 , 1 62, 163, 1 64 may be or include a pipe or any other type of conduit capable of containing and flowing the cooling fluid therethrough. The distribution tubes 161 , 1 62, 163, 1 64 may be sized to supply the cooling fluid at a sufficient pressure and/or volume to the one or more portions of the motor-compressor 100.

[0033] In at least one embodiment, one or more of the distribution tubes 161 , 1 62, 163, 1 64 may be internal distribution tubes (three are shown 1 61 , 1 62, 1 63) and may be completely disposed or contained within the housing 1 10 of the motor-compressor 100. For example, as illustrated in Figure 1 , the internal distribution tubes 161 , 162, 1 63 may be completely contained within the housing 1 10 and may extend from the discharge assembly 154 toward the compressor end 1 1 2 of the housing 1 1 0. In at least one embodiment, the internal distribution tubes 1 61 , 1 62, 1 63 may not be capable of extending through one or more portions of the motor-compressor 100, or the internal distribution tubes 1 61 , 1 62, 163 may not provide a cost effective option for cooling one or more portions of the motor-compressor 1 00. For example, the internal distribution tubes 1 61 , 1 62, 163 may not be capable of effectively directing the cooling fluid from the blower assembly 150 to the radial bearings 1 24 and/or axial bearing 1 26 disposed in the compressor portion 1 13 of the housing 1 10. Accordingly, one or more of the distribution tubes 1 61 , 1 62, 163, 1 64 may be external distribution tubes (one is shown 1 64) having at least a portion thereof disposed external to the housing 1 1 0. The external distribution tube 164 may extend from the discharge assembly 154 to and through the motor end 1 14 of the housing 1 1 0, and may further extend along the exterior of the housing 1 1 0 to thereby provide the cooling fluid to the radial bearings 1 24 and/or the axial bearing 1 26 disposed in the compressor portion 1 1 3 of the housing 1 10.

[0034] As previously discussed, the blower assembly 150 may circulate the cooling fluid throughout the motor-compressor 1 00 via the cooling circuit to regulate the temperature of the motor 1 02, the radial bearings 1 24, and/or the axial bearing 1 26. In at least one embodiment, the cooling circuit may include, but is not limited to, the blower assembly 1 50 and/or components thereof. For example, as illustrated in Figure 1 , the cooling circuit may include the discharge assembly 154, the arms 156, the blower impeller 1 52, the distribution tubes 1 61 , 162, 1 63, 1 64, or any combination thereof. In at least one embodiment, the cooling circuit may also include the cavity 1 22 defined within the housing 1 10 and/or one or more internal cooling passages 1 72, 174, 1 76, 1 78 defined and/or formed in the housing 1 1 0.

[0035] In at least one embodiment, the distribution tubes 161 , 1 62, 1 63, 1 64 may be configured to receive the cooling fluid from the discharge assembly 1 54 and direct the cooling fluid to the internal cooling passages 172, 1 74, 1 76, 1 78 to cool the motor- compressor 100 and/or components thereof. For example, the internal distribution tubes 1 61 , 1 62 may be fluidly coupled with the internal cooling passages 172, 174, respectively, and configured to direct the cooling fluid thereto. The cooling fluid directed to the internal cooling passages 172, 174 may flow through one or more portions of the motor 1 02 to cool one or more components thereof. For example, the cooling fluid in the internal cooling passages 172, 1 74 may flow to the stator 1 32 of the motor 1 02 to remove at least a portion of the heat generated by the motor 1 02. The distribution tubes 1 61 , 162, 163, 1 64 may also be directly coupled with one or more components of the motor-compressor 1 00. For example, as illustrated in Figure 1 , the internal distribution tube 163 may be fluidly coupled with the stator 1 32 of the motor 1 02 and configured to direct the cooling fluid thereto. The cooling fluid directed to the internal cooling passages 172, 174 may flow through the radial bearings 1 24 supporting the motor section 1 16 of the rotary shaft 1 08 to thereby remove at least a portion of heat generated by the radial bearings 124. For example, the cooling fluid in the internal cooling passages 1 72, 1 74 may flow through a gap defined between each of the radial bearings 1 24 and the motor section 1 1 6 of the rotary shaft 1 08 to remove the heat generated by the radial bearings 124.

[0036] As illustrated in Figure 1 , the cooling fluid in the internal cooling passage 174 on a first side of the motor 1 02 (i.e. , the left side as illustrated in Figure 1 ) may flow from the internal cooling passage 1 74 to the cavity 1 22 via the radial bearings 1 24. The heated or spent cooling fluid in the cavity 1 22 may be discharged from the cavity 122 via a return line 1 80 fluidly coupled therewith. The return line 180 may fluidly couple the cavity 1 22 with the inlet 151 of the blower assembly 1 50 and may be configured to direct or cycle the cooling fluid from the cavity 1 22 to the blower assembly 1 50. As further illustrated in Figure 1 , the cooling fluid in the internal cooling passage 1 72 on a second side of the motor 1 02 (i.e., the right side as illustrated in Figure 1 ) may flow through the radial bearings 1 24 and combine with the cooling fluid in the return line 1 80 via line 181 . It should be noted that the terms "left" and "right," or other directions and orientations described herein, are provided for clarity in reference to the Figures and are not intended to be limiting of the actual system or use thereof.

[0037] In at least one embodiment, the external distribution tube 1 64 may be fluidly coupled with the internal cooling passages 176, 1 78, and configured to direct the cooling fluid thereto to cool the respective radial bearings 124 supporting the driven section 1 18 of the rotary shaft 1 08. For example, as illustrated in Figure 1 , the external distribution tube 1 64 may be separated or split into separate lines 1 68, 1 70 fluidly coupled with the internal cooling passages 1 76, 178, respectively. As the cooling fluid nears the radial bearings 1 24 supporting the driven section 1 1 8, the buffer seals 1 40 may prevent the cooling fluid from flowing to portions of the housing 1 10 where the compressor 104 and/or the integrated separator 1 06 may be disposed. Instead, the cooling fluid may flow through the radial bearings 124 supporting the driven section 1 18, and may be subsequently cycled or directed back to the blower assembly 150. For example, the cooling fluid in the internal cooling passage 178 may flow through the radial bearing 124 disposed near or adjacent the compressor end 1 12 of the housing 1 10 and may subsequently be discharged from the housing 1 10 to the cavity 1 22 via line 182. The cooling fluid in the internal cooling passage 178 may also flow through the axial thrust bearings 126 prior to being discharged from the housing 1 1 0 to the cavity 1 22 via line 1 82. The cooling fluid flowing through the internal cooling passage 1 76 may be directed to the cavity 1 22 via the radial bearings 1 24. Accordingly, the spent cooling fluid from the internal cooling passages 1 76, 1 78 may combine with one another in the cavity 1 22, and may further combine with the spent cooling fluid from the internal cooling passage 1 74. As previously discussed, the cooling fluid in the cavity 122 may be discharged from the housing 1 1 0 via the return line 1 80 and subsequently directed or cycled to the inlet 151 of the blower assembly 1 50 fluidly coupled therewith.

[0038] In at least one embodiment, a heat exchanger 184 may be fluidly coupled with the return line 180 upstream of the inlet 1 51 of the blower assembly 1 50. The heat exchanger 1 84 may be configured to cool or reduce the temperature of the cooling fluid (e.g., spent cooling fluid) flowing therethrough. The heat exchanger 1 84 may be any device capable of reducing the temperature of the cooling fluid. Illustrative heat exchangers 184 may include, but are not limited to, a direct contact heat exchanger, a trim cooler, a mechanical refrigeration unit, or any combination thereof. In at least one embodiment, the motor- compressor 1 00 may further include a density based separator (not shown) configured to remove any condensation generated during the cooling of the cooling fluid in the heat exchanger 1 84. The motor-compressor 1 00 may also include a fluid conditioning skid 1 86 fluidly coupled with the return line 1 80 upstream of the inlet 1 51 of the blower assembly 1 50 and configured to filter the cooling fluid flowing therethrough. It may be appreciated that cooling and/or conditioning (e.g. , filtering) the cooling fluid may allow the cooling fluid to be circulated through the cooling circuit with less power from the motor 1 02, thereby increasing the efficiency of the motor-compressor 1 00.

[0039] In exemplary operation of the motor-compressor 100, the motor 1 02 may rotate the motor section 1 1 6 of the rotary shaft 108 and the blower impeller 152 coupled therewith to generate the pressure differential to draw the cooling fluid into the blower assembly 1 50 via the inlet 151 . In at least one embodiment, at least a portion of the pressure differential generated by the blower impeller 152 may be provided by the compression of the cooling fluid within the arms 1 56 of the discharge assembly 154. The differential pressure generated via the rotation of the blower impeller 152 may circulate or flow the cooling fluid through the motor-compressor 1 00 via the cooling circuit. The cooling fluid circulating through the cooling circuit may absorb at least a portion of the heat or thermal energy generated by the motor-compressor 1 00 and/or components thereof. The spent cooling fluid may be subsequently cooled and/or treated in the heat exchanger 1 84 and/or the fluid conditioning skid 186, respectively, and directed back to the inlet 1 51 of the blower assembly 1 50 via the return line 180.

[0040] It may be appreciated that the motor-compressor 100 may include a control system (not shown) having one or more pressure and/or temperature sensors operably coupled with one or more components thereof and configured to monitor and/or regulate one or more operating parameters thereof. Illustrative operating parameters may include, but are not limited to, temperatures, pressures, flowrates, rotational speed of the motor 1 02, and the like. In at least one embodiment, the control system may be communicably and operatively coupled with the motor-compressor and/or components thereof. For example, the control system may include a programmable logic controller (PLC) with inputs from the motor-compressor 100 and/or components thereof and outputs for controlling the operating parameters. The control system may be integral with the motor-compressor 1 00 or the control system may be remote. The control system may also be programmable to control or change any of the varying operating parameters of the motor-compressor 1 00.

[0041] Figure 2A illustrates a cross-sectional, perspective view of a motor portion 201 of another motor-compressor 200, according to one or more embodiments. Figure 2B illustrates an enlarged view of the portion of the motor-compressor 200 indicated by the box labeled "2B" of Figure 2A, according to one or more embodiments. The motor- compressor 200 illustrated in Figures 2A and 2B may be similar in some respects to the motor-compressor 1 00 described above and therefore may be best understood with reference to the description of Figure 1 , where like numerals designate like components and will not be described again in detail.

[0042] As illustrated in the cross-sectional view in Figure 2B, and further illustrated in the perspective view in Figure 2C, the discharge assembly 1 54 may include a discharge housing 21 0 and a cover plate 21 2 coupled with one another. As illustrated in Figure 2B, the discharge housing 21 0 may be disposed circumferentially about and radially outward of the rotary shaft 1 08, and the cover plate 212 may be coupled with an axial end portion of the discharge housing 21 0. The discharge housing 210 and the cover plate 212 may at least partially define an annular volume 214 in the hub portion 155 of the discharge assembly 1 54. The blower impeller 1 52 may be coupled with the end portion of the rotary shaft 1 08, and may be at least partially disposed in the annular volume 21 4 between the discharge housing 21 0 and the cover plate 212. In at least one embodiment, the blower impeller 152 may include an impeller eye 216 axially aligned and coupled with the rotary shaft 108. The inlet 151 defined by the motor end 1 14 of the housing 1 1 0 may be in fluid communication with the annular volume 214 of the discharge assembly 1 54 and the blower impeller 152 disposed therein.

[0043] In at least one embodiment, one or more seals or seal systems (not shown) may be disposed between axial interfacing surfaces of the blower impeller 152 and the discharge housing 21 0 to prevent or reduce the cooling fluid from flowing therebetween. The seals or seal systems may also be disposed between axial interfacing surfaces of the blower impeller 152 and the cover plate 21 2 to prevent or reduce the cooling fluid from flowing therebetween. Accordingly, the cooling fluid directed to the annular volume 214 from the inlet 151 may be prevented from flowing around the blower impeller 1 52, and may instead be directed to and through the blower impeller 152.

[0044] As illustrated in Figures 2A and 2B, the discharge assembly 1 54 may include one or more arms (four are shown 221 , 222, 223, 224). The arms 221 , 222, 223, 224 may extend outward from the hub portion 155 of the discharge assembly 1 54 to the distribution tubes 1 61 , 162, 163, 164. The arms 221 , 222, 223, 224 may be fluidly coupled with the hub portion 1 55 of the discharge assembly 1 54 and configured to receive the cooling fluid from the annular volume 214 defined therein. The arms 221 , 222, 223, 224 may receive the cooling fluid from the annular volume 21 4 and direct the cooling fluid to the distribution tubes 161 , 1 62, 163, 1 64. For example, the arms 221 , 222, 223, 224 may be fluidly coupled with the internal distribution tubes 161 , 162, 163, and the external distribution tube 164, respectively, and configured to direct the cooling fluid thereto. As previously discussed, the internal distribution tubes 1 61 , 162 may be fluidly coupled with the internal passages 172, 1 74, respectively, and configured to direct the cooling fluid to the internal cooling passages 172, 1 74 and configured to direct the cooling fluid thereto. Further, as previously discussed with reference to Figure 1 , the external distribution tube 164 may be fluidly coupled with the internal cooling passages 1 76, 178 and configured to direct the cooling fluid to the internal cooling passages 176, 1 78 to cool the respective radial bearings 1 24 that support the driven section 1 1 8 of the rotary shaft 1 08. It may be appreciated that each of the arms 221 , 222, 223, 224 and/or the distribution tubes 161 , 1 62, 1 63, 164 disclosed herein may include similar components and parts. Consequently, discussions herein regarding a single arm 222 and/or distribution tube 162 are equally applicable to the remaining arms 221 , 223, 224 and/or distribution tubes 161 , 163, 164.

[0045] Figure 2D illustrates a perspective view of the blower assembly 1 50 of the motor- compressor 200 of Figures 2A and 2B having the cover plate 212 removed, according to one or more embodiments. As illustrated in Figure 2D, the hub portion 155 of the discharge assembly 154 may include a diffuser portion 240 disposed between the blower impeller 152 and the arms 221 , 222, 223, 224. The discharge housing 210 and the cover plate 212 may at least partially define the diffuser portion 240. The diffuser portion 240 may be a vaneless diffuser and may be configured to convert kinetic energy (e.g. , flow or velocity) of the cooling fluid from the blower impeller 152 to potential energy (e.g., pressure) by reducing the flow thereof. Accordingly, the diffuser portion 240 may be configured to receive the cooling fluid from the blower impeller 1 52, reduce the flow of the cooling fluid from the blower impeller 1 52, and diffuse the flow of the cooling fluid to a higher static pressure. The diffuser portion 240 may also be configured to redirect the flow of the cooling fluid from the blower impeller 152 to the arms 221 , 222, 223, 224 fluidly coupled therewith. For example, the cooling fluid directed to the arms 221 , 222, 223, 224 from the diffuser portion 240 may flow in generally tangential and/or radial directions to thereby provide a swirling flow.

[0046] As illustrated in Figures 2C and 2D, the arms 221 , 222, 223, 224 may be coupled with the hub portion 1 55 and may extend from the hub portion 155 toward the respective distribution tubes 161 , 1 62, 1 63, 164. In at least one embodiment, the arms 221 , 222, 223, 224 may extend outward from the hub portion 155. For example, the arms 221 , 222, 223, 224 may extend generally tangential from the hub portion 1 55. As further illustrated in Figures 2C and 2D, the arms 221 , 222, 223, 224 may be uniformly arranged about the hub portion 1 55 in an annular array. The uniform arrangement of the arms 221 , 222, 223, 224 may allow uniform distribution of the cooling fluid from the diffuser portion 240 and/or the blower impeller 152 to the distribution tubes 1 61 , 1 62, 163, 164.

[0047] As illustrated in Figure 2D, the arm 222 may have an inlet 232 fluidly coupled with the hub portion 1 55 and an outlet 234 fluidly coupled with the distribution tube 162. As further illustrated in Figure 2D, the arm 222 may include a flow passage 236 extending between the inlet 232 and the outlet 234. The cooling fluid from the diffuser portion 240 and/or the blower impeller 152 may be directed to the distribution tube 1 62 via the flow passage 236 extending between the inlet 232 and the outlet 234. In at least one embodiment, the arm 222 may further diffuse the flow of the cooling fluid from the diffuser portion 240. For example, the arm 222 may receive the cooling fluid from the diffuser portion 240 and further convert kinetic energy (e.g., flow or velocity) of the cooling fluid to potential energy (e.g., pressure) by further reducing the flow thereof. The inlet 232 and the outlet 234 of the arm 222 may be circumferentially offset from one another such that the arm 222 may be angled or have an angular orientation. For example, the inlet 232 of the arm 222 may be circumferentially offset from the outlet 234 of the arm 222 such that the arm 222 may extend generally tangential from the hub portion 155 to the distribution tube 1 62. In at least one embodiment, at least a portion of the arm 222 may be arcuate or curved. For example, at least a portion of the arm 222 may be curved between the inlet 232 and the outlet 234 thereof.

[0048] In exemplary operation of the motor-compressor 200, with continued reference to Figures 1 and 2A-2D, the motor 102 may rotate the motor section 1 16 of the rotary shaft 1 08 and the blower impeller 152 coupled therewith. The blower impeller 1 52 disposed in the hub portion 1 55 of the discharge assembly 1 54 may rotate therein relative to the discharge housing 210 and the cover plate 21 2 of the discharge assembly 154, all of which may be generally stationary. The rotation of the blower impeller 152 may generate the pressure differential to draw or direct the cooling fluid to the inlet 151 of the blower assembly 1 50 and the blower impeller 152 disposed therein. The pressure differential may further circulate the cooling fluid through the cooling circuit. The cooling fluid directed to the blower impeller 1 52 may be subsequently directed to the diffuser portion 240 defined in the hub portion 155 of the discharge assembly 1 54 between the blower impeller 1 52 and the arms 221 , 222, 223, 224.

[0049] The diffuser portion 240 may receive the cooling fluid from the blower impeller 1 52 and may at least partially convert the kinetic energy of the cooling fluid to potential energy by reducing the flow and increasing the pressure thereof. The diffuser portion 240 may also redirect the flow of the cooling fluid from the blower impeller 1 52 to the arms 221 , 222, 223, 224. For example, the cooling fluid from the blower impeller 152 may flow in the radially outward direction toward the diffuser portion 240, and the diffuser portion 240 may redirect the flow of the cooling fluid in the generally tangential and generally radial directions (e.g., swirling flow). In at least one embodiment, the angular and/or generally tangential orientation of the arms 221 , 222, 223, 224 may be substantially aligned with the flow direction (e.g., swirling flow) of the cooling fluid from the diffuser portion 240. Accordingly, the cooling fluid from the diffuser portion 240 may be directed to the arms 221 , 222, 223, 224 without substantially redirecting or changing the flow direction of the cooling fluid, thereby reducing or preventing pressure losses in the cooling fluid directed to the arms 221 , 222, 223, 224. The arms 221 , 222, 223, 224 may receive the cooling fluid from the diffuser portion 240 and direct the cooling fluid to the distribution tubes 1 61 , 1 62, 1 63, 1 64 fluidly coupled therewith. The distribution tubes 161 , 162, 163, 164 may receive the cooling fluid from the arms 221 , 222, 223, 224 and direct the cooling fluid to one or more portions of the motor-compressor 200.

[0050] Figure 3 illustrates a flowchart of a method 300 for cooling a motor-compressor, according to one or more embodiments. The method 300 may include supporting each end portion of a rotary shaft in a housing of the motor-compressor with radial bearings, as shown at 302. The method 300 may also include rotating the rotary shaft with a motor coupled therewith, as shown at 304. The method 300 may further include driving a blower impeller coupled with the rotary shaft, as shown at 306. The method 300 may further include directing a cooling fluid to a discharge assembly disposed radially outward of the rotary shaft, the discharge assembly at least partially defining an annular volume in a hub portion of the discharge assembly, as shown at 308. The method 300 may also include discharging the cooling fluid from the discharge assembly to the plurality of internal cooling passages via a plurality of arms extending outward from the hub portion of the discharge assembly to thereby cool the motor-compressor, as shown at 31 0.

[0051] The foregoing has outlined features of several embodiments so that those skilled in the art may better understand the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.

Claims

Claims I claim:

1 . A cooling system for a motor-compressor, comprising:

a discharge assembly comprising a hub portion disposed radially outward of a rotary shaft of the motor-compressor and a plurality of arms fluidly coupled with and extending generally tangential from the hub portion, the hub portion defining an annular volume fluidly coupled with the plurality of arms; and

a blower impeller disposed in the annular volume and coupled with the rotary shaft, the blower impeller configured to rotate with the rotary shaft and draw a cooling fluid into the discharge assembly.

2. The cooling system of claim 1 wherein the discharge assembly further comprises a discharge housing and a cover plate coupled with one another, the cover plate and the discharge housing at least partially defining the annular volume.

3. The cooling system of claim 1 , wherein the discharge assembly further comprises a diffuser portion disposed between the blower impeller and the plurality of arms, the diffuser portion configured to receive the cooling fluid from the blower impeller and direct the cooling fluid to the plurality of arms.

4. The cooling system of claim 1 , further comprising:

a return line fluidly coupled with an inlet of the discharge assembly and configured to direct the cooling fluid thereto; and

a heat exchanger fluidly coupled with the return line upstream of the inlet of the discharge assembly and configured to cool the cooling fluid flowing therethrough.

5. The cooling system of claim 1 , further comprising a plurality of distribution tubes, a respective one of the plurality of distribution tubes fluidly coupling a respective one of the plurality of arms with at least one internal cooling passage of the motor-compressor.

6. The cooling system of claim 5, wherein at least one of the plurality of distribution tubes is an internal distribution tube contained in a housing of the motor-compressor.

7. The cooling system of claim 5, wherein at least one of the plurality of distribution tubes is an external distribution tube, and at least a portion of the external distribution tube is disposed external to a housing of the motor-compressor.

8. A motor-compressor, comprising:

a housing having a motor end and a compressor end, the housing defining a plurality of internal cooling passages;

a motor coupled with a rotary shaft and in fluid communication with at least one of the plurality of internal cooling passages;

radial bearings disposed proximal each end portion of the rotary shaft, the radial bearings in fluid communication with at least one of the plurality of internal cooling passages;

a discharge assembly comprising a hub portion disposed radially outward of the rotary shaft and a plurality of arms fluidly coupled with and extending outward from the hub portion, the hub portion defining an annular volume fluidly coupled with the plurality of arms; and

9. The motor-compressor of claim 8, wherein the plurality of arms extend generally tangential from the hub portion of the discharge assembly.

1 0. The motor-compressor of claim 8, further comprising:

a heat exchanger fluidly coupled with the return line upstream of the inlet of the discharge assembly and configured to cool the cooling fluid flowing through the return line.

1 1 . The motor-compressor of claim 8, further comprising a plurality of distribution tubes, a respective one of the plurality of distribution tubes fluidly coupling a respective one of the plurality of arms with at least one internal cooling passage of the motor- compressor.

1 2. The motor-compressor of claim 1 1 , wherein at least one of the plurality of distribution tubes extends from the discharge assembly to and through the motor end of the housing.

1 3. The motor-compressor of claim 8, wherein the discharge assembly further comprises a diffuser portion disposed between the blower impeller and the plurality of arms, the diffuser portion configured to redirect the cooling fluid from the blower impeller to the plurality of arms.

1 4. The motor-compressor of claim 13, wherein the diffuser portion is a vaneless diffuser.

1 5. A method for cooling a motor-compressor, comprising:

supporting each end portion of a rotary shaft in a housing of the motor-compressor with radial bearings, the housing defining a plurality of internal cooling passages, and at least one of the plurality of internal cooling passages being in fluid communication with at least one of the radial bearings;

rotating the rotary shaft with a motor coupled therewith;

driving a blower impeller coupled with the rotary shaft;

directing a cooling fluid to a discharge assembly disposed radially outward of the rotary shaft, the discharge assembly at least partially defining an annular volume in a hub portion of the discharge assembly; and

discharging the cooling fluid from the discharge assembly to the plurality of internal cooling passages via a plurality of arms extending outward from the hub portion of the discharge assembly to thereby cool the motor-compressor.

1 6. The method of claim 15, further comprising cooling the cooling fluid directed to the discharge assembly with a heat exchanger.

1 7. The method of claim 1 5, further comprising directing the cooling fluid from the blower impeller to the plurality of arms via a diffuser portion of the discharge assembly.

1 8. The method of claim 15, wherein the plurality of arms extend generally tangential from the hub portion of the discharge assembly.

1 9. The method of claim 1 5, further comprising directing the cooling fluid from the plurality of arms to the plurality of internal cooling passages via a plurality of distribution tubes.

20. The method of claim 15, wherein the discharge assembly comprises a discharge housing and a cover plate coupled with one another, the cover plate and the discharge housing at least partially defining the annular volume in the hub portion of the discharge assembly.