Magnetic thrust bearing with pressure feeding effect

Abstract

The magnetic thrust bearing (1000) comprises a rotor assembly (300) comprising a thrust disk (110, 210) arranged to rotate about an axis (X) and receive cooling fluid at an inner area about the axis (X) and discharge cooling fluid at an outer area about the periphery of the thrust disk. The thrust disk (110, 210) comprises a number of blades located at the periphery of the thrust disk that are configured to pump fluid as a result of rotation of the rotor assembly (300) to avoid the use of an external blower or additional impellers to flow the cooling fluid and preferably to enable cooling fluid recirculation in a closed loop configuration.

Description

Technical Field

[0001] The subject matter disclosed herein relates to a magnetic thrust bearing cooled by a cooling fluid.

Background Art

[0002] Magnetic bearings are mainly used to control the position of a rotor of a machine on which the magnetic bearing is installed, due to several advantages including very low and predictable friction, and the ability to operate without lubrication and in a vacuum. Typically, magnetic bearings are used in industrial machines such as compressors, turbines, pumps, motors and generators.

[0003] In particular, the magnetic bearing can be an active magnetic bearing (=Active Magnetic Bearing, AMB) or a passive magnetic bearing (=Passive Magnetic Bearing, PMB). The passive magnetic bearing uses permanent magnets to generate magnetic levitation. However, the passive magnetic bearing is difficult to design. As a result, most magnetic bearings currently used in machines are active magnetic bearings.

[0004] Generally, an active magnetic bearing is an electromagnetic system having a stator with several electromagnets positioned around a rotor typically coupled to a shaft, and the electromagnets of the stator generate an attractive force on the rotor to maintain the position of the rotor relative to the stator.

[0005] Currently, rotating machinery equipped with magnetic bearings is also provided with a cooling system to dissipate heat within the magnetic bearings, and the cooling system includes an external blower or additional impeller mounted on the shaft of the rotating machinery to circulate a cooling fluid. For example, European Patent No. 3450701 and International Publication No. 2017050445 disclose a turbomachinery system coupled to an active magnetic bearing that includes a cooling circuit for circulating a cooling fluid to remove heat from it. In European Patent No. 3450701, the cooling fluid is recirculated by an additional impeller mounted on the machine shaft, while in International Publication No. 2017050445, the cooling fluid is circulated by an external blower. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Therefore, rotating machinery equipped with magnetic bearings must be provided with at least dedicated components to enable the circulation or recirculation of the cooling flow.

[0007] To reduce the number of so-called "auxiliary components," i.e., auxiliary devices, of the machine (and thus reduce the electrical energy supplied to these "auxiliary components"), and to increase the machine's availability, it is desirable to have cooled magnetic bearings that avoid the use of dedicated components for circulating or recirculating the cooling flow.

[0008] In one embodiment, the subject disclosed herein relates to a cooled magnetic thrust bearing having a rotor assembly comprising a thrust disc that rotates around an axis and is arranged to receive a cooling fluid. The thrust disc comprises a plurality of blades configured to pressurize the fluid as a result of the rotation of the rotor assembly in order to enable cooling fluid circulation, in particular cooling fluid recirculation in a closed-loop configuration.

[0009] In another embodiment, the subject matter disclosed herein relates to a rotating machine provided with a cooled magnetic thrust bearing, wherein the rotor assembly of the cooled magnetic thrust bearing is coupled to the shaft of the rotating machine. [Brief explanation of the drawing]

[0010] Many of the disclosed embodiments of the present invention and their associated advantages will be better understood by referring to the following embodiments for carrying out the invention, and a complete understanding will be easily obtained, as they are considered in relation to the accompanying drawings. [Figure 1] Figure 1 shows a schematic and simplified cross-sectional view of a rotating machine, particularly an expander-compressor system, that has an embodiment of an innovative magnetic thrust bearing. [Figure 2] Figure 2 shows a more detailed view of a partial cross-section of the magnetic thrust bearing coupled to the rotating machine in Figure 1. [Figure 3] Figure 3 partially shows a front and cross-sectional schematic view of a first embodiment (not fully covered by the appended claims) of an innovative magnetic thrust bearing having a thrust disk with multiple grooves. [Figure 4] Figure 4 partially shows a simplified front view and a simplified cross-sectional view of a second embodiment of an innovative magnetic thrust bearing having a thrust disk with multiple blades. [Figure 5] Figure 5 shows a simplified cross-sectional view of an example of a joint that can be used to connect multiple blades to the thrust disk of a second embodiment of the innovative magnetic thrust bearing shown in Figure 4. [Figure 6] Figure 6 shows a simplified partial top view of a third embodiment of an innovative magnetic thrust bearing having a thrust disk with multiple grooves and multiple blades. [Modes for carrying out the invention]

[0011] The subject matter disclosed herein relates to an innovative magnetic thrust bearing that, due to its internal design, can pump cooling fluid without requiring an external blower or additional impeller. In other words, the magnetic thrust bearing performs both its conventional thrust balancing function and its innovative cooling fluid pumping function.

[0012] According to a second aspect, the subject matter disclosed herein relates to rotating machinery, particularly compressors or expander-compression systems. The rotating machinery has a novel magnetic thrust bearing in which a rotor assembly is integrated with the shaft of the rotating machine. The shaft of the rotating machine is configured to rotate, and the cooling fluid of the magnetic thrust bearing is pumped as a result of the rotation of the rotor assembly.

[0013] Embodiments of the present disclosure will be described in detail, with examples illustrated in the drawings. Each example is provided for illustrative purposes only and is not limiting to the present disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure, without departing from the scope or spirit of the present disclosure. In the following description, similar reference numerals are used to illustrate the embodiments in the drawings to indicate elements that perform the same or similar functions. Furthermore, for clarity in the illustrations, some reference numerals may not be repeated in all drawings.

[0014] According to a first aspect, the subject disclosed herein relates to a rotating machine 2000 equipped with an innovative magnetic thrust bearing 1000, a simplified cross-sectional view of one embodiment of the machine shown in Figure 1. Advantageously, the rotating machine 2000 is an expander-compressor system comprising an expander 2800, a compressor 2900, and a shaft 2100 mechanically coupling the expander 2800 and the compressor 2900. As is clear from Figure 1, the compressor 2900 is located at a first end of the shaft 2100, and the expander 2900 is located at a second end of the shaft. In other embodiments, the rotating machine 2000 may be a compressor having a shaft coupling the compressor to a motor, particularly an electric motor.

[0015] Figure 1 schematically shows a magnetic thrust bearing 1000 including a rotor assembly 300 and a stator assembly 400. As shown in the figure, all of these elements can be housed within a casing 2200 of a rotating machine 2000. The rotor assembly 300 (including the thrust discs 110 / 210 described later) is configured to rotate around an axis X, and in particular, the rotor assembly 300 can be integrated with the shaft 2100 of the rotating machine 2000, or coupled to the shaft 2100 of the rotating machine 2000, particularly welded, and more advantageously, the axis X of the rotor assembly 300 is also the axis of the shaft 2100 of the rotating machine 2000. In other words, the rotor assembly 300 is configured to rotate together with the rotor of the rotating machine (including the thrust discs), for example, since the rotor assembly 300 may be part of the rotor of the rotating machine 2000, particularly the shaft 2100. For example, Figure 2 shows a partial cross-sectional view of a rotor magnetic thrust bearing 1000 coupled to a shaft 2100.

[0016] With non-limiting reference to Figures 1 and 2 and Figures 3 and 4, the rotor assembly 300 includes thrust discs 110 / 210 (110 in Figure 3 and 210 in Figure 4) configured to rotate around an axis X, in particular together with the shaft 2100 of the rotating machine 2000. The thrust discs 110 / 210 have first sides 101 / 201 and second sides 102 / 202, in particular, such that the thrust discs 110 / 210 are positioned in the middle portion of the shaft 2100, preferably in the middle of the shaft length, with the first sides 101 / 201 facing the first end of the shaft 2100 and the second sides 102 / 202 facing the second end of the shaft 2100.

[0017] Typically, the thrust disc 110 / 210 has an inner circumference 112 / 212 and an outer circumference 114 / 214, and advantageously, the inner circumference 112 / 212 is positioned to be coupled to the shaft 2100 of the rotating machine 2000. Note that the thickness of the thrust disc 110 / 210 may vary between the inner circumference 112 / 212 and the outer circumference 114 / 214. For example, the thickness of the thrust disc 110 / 210 may be greater at the inner circumference 112 / 212 than at the outer circumference 114 / 214. According to an advantageous embodiment similar to the embodiment in Figure 2, the thrust disc 110 / 210 is, - A first portion that begins at the inner circumference 112 / 212 of the disk, is coupled to the shaft 2100, and has the greatest thickness at the inner circumference 112 / 212, preferably the thickness of the first portion is gradually reduced from the greatest thickness to a first reduced thickness, - A second portion having a constant thickness, preferably the constant thickness of the second portion being equal to the first reduced thickness of the first portion, -The third portion 115 / 215 (hereinafter also called the "intermediate region") is a third portion whose thickness starts from a constant thickness in the second portion and gradually decreases, in other words, the thickness of the third portion gradually decreases from a constant thickness in the second portion to the second reduced thickness, and - The fourth portion may have a constant thickness, starting at the outer circumference 114 / 214 of the disk, wherein the constant thickness of the fourth portion is equal to the second reduced thickness of the third portion.

[0018] According to embodiments of Figures 1 and 2, the stator assembly 400 comprises at least two magnet assemblies 412 and 414, the first magnet assembly 412 facing the first side surfaces 101 / 201 of the thrust disk 110 / 210, and the second magnet assembly 414 facing the second side surfaces 102 / 202 of the thrust disk 110 / 210. Preferably, the magnet assemblies 412 and 414 are ring-shaped, and more preferably, the magnet assemblies 412 and 414 are arranged around an axis X.

[0019] Referring non - limitingly to FIG. 2, the stator assembly 400 is fixed to a wall which can be the inner wall 2210 of the casing 2200 of the rotating machine 2000. In particular, the stator assembly 400 may be embedded in the wall such that the sides of the magnet assemblies 412 and 414 face the thrust disks 110 / 210. Advantageously, a gap exists between the rotor assembly 300 and the stator assembly 400. More advantageously, the sides of the magnet assemblies 412 and 414 facing the thrust disks 110 / 210 have protection plates 422 and 424 made especially of bakelite, for example, to protect the magnet assemblies 412 and 414 from, for example, wear and / or corrosion and / or heat.

[0020] Considering FIGS. 1 and 2, the magnetic thrust bearing 1000 has at least a fluid inlet and a fluid outlet and is configured to be cooled by a fluid, particularly a gas. At least the first side 10 / 201 of the thrust disk 110 / 210, preferably both the first side 101 / 201 and the second side 102 / 202 of the thrust disk 110 / 210, are configured to receive the fluid. Preferably, the magnetic thrust bearing 1000 has a first fluid inlet 401 - 1 for the fluid to enter at the first side 101 / 201 of the thrust disk 110 / 210 and a second fluid inlet 401 - 2 for the fluid to enter at the second side 102 / 202 of the thrust disk 110 / 210 (see the two horizontal arrows in FIG. 2). Preferably, the fluid outlet 402 is at the outer periphery 114 / 214 of the thrust disk 110 / 210. (For example, see the vertical arrow in FIG. 2).

[0021] The magnetic thrust bearing 1000 is configured to be cooled by a fluid that enters fluid inlets 401-1 and 401-2, flows from fluid inlets 401-1 and 401-2 to fluid outlet 402, and exits from fluid outlet 402 at a higher temperature than the fluid temperature at fluid inlets 401-1 and 401-2. Advantageously, the fluid may be the working fluid of a rotating machine (i.e., a process gas). Note that if the process gas composition contains contaminants such as H2S, CO2, etc., so-called "equipment air," which is typically readily available and usable in industrial plants (e.g., for pneumatic equipment or valve operation), may be used.

[0022] Advantageously, the fluid preferably enters the casing 2200 of the rotary machine 2000 at least through the inlet flange, and preferably flows substantially axially (i.e., parallel to the axis X as shown, for example, in FIGS. 1 and 2) in the gap between the shaft 2100 and the inner wall of the casing 2200 of the rotary machine 2000, and substantially axially (see FIGS. 1 and even better FIGS. 2), at the inner circumference 112 / 212 of the thrust disks 110 / 210, enters the magnetic thrust bearing 100 through the fluid inlets 401-1 and 401-2. After being cooled by the fluid, the magnetic thrust bearing 100 is configured to discharge the fluid substantially radially (i.e., perpendicular to the axis X as shown, for example, in FIGS. 1 and 2) through the fluid outlet 402 at the outer circumference 114 / 214 of the thrust disks 110 / 210. Advantageously, the fluid outlet 402 of the magnetic thrust bearing 100 is fluidly coupled to the inner chamber 2220 of the casing 2200, and then the fluid preferably exits the casing 2200, particularly the inner chamber 2220, through the outlet flange. More advantageously, the fluid is arranged to flow in a closed-loop configuration, particularly with a cooling system coupled to the inlet and outlet flanges, and as will become apparent hereinafter, is recirculated in a closed-loop configuration only by the magnetic thrust bearing 100 due to its pumping effect. Referring non-limitingly to FIG. 1, the closed-loop configuration is arranged at least partially outside the casing 2200. Advantageously, the cooling system also comprises a heat exchanger 2300 configured to remove heat from the fluid discharged from the fluid outlet 402.

[0023] FIGS. 3A, 3B, 4A and 4B schematically show two embodiments of the thrust disks 110 (FIG. 3) and 210 (FIG. 4) of the innovative magnetic thrust bearing 1000 according to the present disclosure.

[0024] Figures 3A and 3B partially illustrate, but are not limiting, a first embodiment of a thrust disc 110 having multiple grooves configured to pump fluid (not fully covered by the appended claims). Figure 1A is a schematic front view of the thrust disc 110, and Figure 1B is a schematic cross-sectional view of the thrust disc 110 in Figure 1A along the dotted line. Figures 4A and 4B partially illustrate, but are not limiting, a second embodiment of a thrust disc 210 having multiple blades configured to pump fluid. Figure 4A is a schematic front view of the thrust disc 210, and Figure 4B is a schematic cross-sectional view of the thrust disc 210 in Figure 4A along the dotted line D.

[0025] According to the first embodiment, at least one first side surface 101 of the thrust disk 110 is provided with a plurality of grooves 151 configured to pump fluid as a result of the rotation of the rotor assembly 300 of the thrust magnetic bearing 1000. In a preferred embodiment (see Figure 3B), the thrust disk 110 is provided with a plurality of grooves 151-1 on the first side surface 101 and a plurality of grooves 151-2 on the second side surface 102, wherein grooves 151-1 and 151-2 are configured to pump fluid as a result of the rotation of the rotor assembly 300 of the thrust magnetic bearing 1000.

[0026] Advantageously, as shown in Figures 3A and 3B, the groove 151 extends from an area around the inner circumference 112 of the thrust disk 110 to an area around the outer circumference 114 of the thrust disk 110, and in particular, the groove 151 extends continuously from an area around the inner circumference 112 of the thrust disk 110 to an area around the outer circumference 114 of the thrust disk 110. Alternatively, for example, if the thrust disk 110 is manufactured as shown in Figure 2, the groove 151 may extend from an area around the inner circumference 112 of the thrust disk 110 to an area around the intermediate region 115 of the thrust disk 110, and in particular, the groove 151 extends to a first constant thickness portion of the thrust disk 110. Alternatively or additionally, the groove 151 may extend from the area around the intermediate region 115 of the thrust disk 110 to the area around the outer circumference 114 of the thrust disk 110, in particular, the groove 151 may extend to a second constant thickness portion of the thrust disk 110. Note that the groove 151 may be present only on the first side surface 101 or the second side surface 102 of the thrust disk 110, or alternatively, on both the first and second side surfaces of the thrust disk 110 (see, for example, the embodiment in Figure 3B).

[0027] Advantageously, the groove 151 is curved in shape, and more advantageously, the groove 151 is configured to define a preferred direction to which the fluid can follow. It should be noted that the width and / or depth of the groove 151 do not have to be constant, for example, the width in the area around the inner circumference 112 may be greater than the width in the area around the outer circumference 114. Advantageously, if the thrust disc 110 has grooves 151 on both the first side 101 and the second side 102, it is preferable that the geometric shape of the groove 151 is the same on both the first side 101 and the second side 102 of the thrust disc 110.

[0028] Advantageously, the fluid entering the magnetic thrust bearing 1000 to cool it flows over the thrust disk 110 from the area around the inner circumference 112 to the area around the outer circumference 114. More advantageously, the majority of the fluid flowing over the thrust disk 110 is configured to flow in a preferred direction defined by the groove 151. In other words, the fluid is guided to flow along the groove 151, and thereafter, with the rotation of the rotor assembly 300 due to the rotation of the shaft 2100, the groove 151 is configured to pump the fluid. Note that the fluid flowing along the groove 151 is subject to the pumping effect of the thrust disk 110. Generally, the fluid flowing outside the groove 151 is not subject to the pumping effect of the thrust disk 110.

[0029] According to the second embodiment shown in Figure 4, the thrust disc 210 comprises a plurality of blades 252 on its outer circumference 214, configured to pump fluid as a result of the rotation of the rotor assembly 300 of the thrust magnetic bearing 1000. The blades 252 can be obtained directly from the thrust disc 210 by machining the disc, or they can be attached to the thrust disc 210 by welding or joining. It should be noted that when the blades 252 are attached to the thrust disc 210, they may be made of a different material than the material of the thrust disc 210. For example, the blades 252 may be made of a composite material. It should also be noted that when the blades 252 are added by joining, known joints may be used. Preferably, for example, according to Figure 5, the blades 252 are attached to the thrust disc 210 by dovetail joints, in particular, two possible joints are shown in Figure 5, where the first group of blades have fir-tree joints and the second group of blades have dovetail joints.

[0030] Advantageously, the blade 252 is smaller than the thrust disc 210, and in particular, the height of the blade 252 may be in the range of 5 to 15% of the diameter of the thrust disc 210 (measured at the outer circumference 214). Advantageously, the width of the blade 252 is less than or equal to the thickness of the thrust disc 210, and preferably, the width of the blade 252 may be in the range of 70 to 100% of the thickness of the thrust disc 210 (see, for example, Figure 6).

[0031] In another embodiment shown in Figure 6, the thrust disc 210 has both a plurality of grooves 251 and a plurality of blades 252. In particular, with non-limiting reference to Figure 6, the thrust disc 210 has a plurality of grooves 251 on both sides 201 and 202 of the thrust disc 210 and a plurality of blades 252 on its outer circumference 214. In particular, Figure 6 is a simplified partial top view of the thrust disc 210, in which a first groove 251-1 on a first side 201 of the thrust disc 210 and a second groove 251-2 on a second side of the thrust disc 210 can be seen, advantageously, the first groove 251-1 and the second groove 251-2 terminate at the outer circumference 214 of the thrust disc 210. It should be noted that the blade 252 may have a blade profile having two concave surfaces, particularly two curved edges, for example, to make the pumping effect on the fluid more effective and / or to help collect the fluid at the outer circumference 214 of the thrust disc. In particular, the blade 252 may have a first concave surface oriented toward the first side surface 201 and a second concave surface oriented toward the second side surface 202, preferably the first and second concave surfaces of the blade 252 forming a central ridge of the blade profile. Alternatively, the blade 252 may have two oblique edges having a flat shape (i.e., without concave surfaces), with the first edge oriented toward the first side surface 201 and the second edge oriented toward the second side surface 202, preferably the first and second edges forming a central ridge of the blade profile. As shown in Figure 6, the fluid exits from the first groove 251-1 and the second groove 251-2, flows over the fluid-feeding blade 252, and exits from the blade according to the profile of the blade 252 (see the two large arrows in Figure 6). Referring non-limitingly to Figure 6, note that the blade 252 is located on the outer circumference 214 of the thrust disc 210 to which the ends of the first groove 251-1 and the second groove 251-2 terminate. Advantageously, at least some of the multiple blades 252 are located at at least some of the ends of the multiple grooves 251. Note also that the thrust disc 210 in Figure 6 rotates in the same direction as the exit direction of the fluid from the blades 252.

[0032] It should be noted that the blade cross-section shown in Figure 6 (or a similar cross-section having a first concave surface oriented toward the first side surface and a second concave surface oriented toward the second side surface) can be advantageously used in a thrust disc even without being combined with grooves on its surface or multiple surfaces.

Claims

1. A magnetic thrust bearing (1000), - A rotor assembly (300) configured to rotate, comprising a thrust disc (110, 210) having first sides (101, 201) and second sides (102, 202), - A stator assembly (400) comprising magnet assemblies (412, 414) that act on the thrust disks (110, 210), The magnetic thrust bearing (1000) is configured to be cooled by a fluid, At least the first side surface (101, 201) of the thrust disc (110, 210) is configured to receive the fluid substantially in the axial direction, and the outer circumference (114, 214) of the thrust disc (110, 210) is configured to discharge the fluid substantially in the radial direction. The thrust disc (110, 210) is provided with a plurality of blades (252) on its outer circumference (114, 214), The plurality of blades (252) are configured to pump the fluid as a result of the rotation of the rotor assembly (300), The thrust disc (110, 210) further comprises a plurality of grooves (151, 251) on the first side surface (101, 201), The plurality of grooves (151, 251) are configured to pump the fluid as a result of the rotation of the rotor assembly (300), The plurality of grooves (151, 251) extend continuously from the inner circumference (112, 212) of the thrust disk (110, 210) to the outer circumference (114, 214) of the thrust disk (110, 210), forming a magnetic thrust bearing (1000).

2. The stator assembly preferably comprises at least two magnet assemblies (412, 414), wherein the first magnet assembly (412) faces the first side surface (101, 201), and the second magnet assembly (414) faces the second side surface (102, 202). The magnetic thrust bearing (1000) has at least one fluid inlet (401-1, 401-2) and a fluid outlet (402), and is configured to be cooled by the fluid that enters the at least one fluid inlet (401-1, 401-2), flows from the fluid inlet (401-1, 401-2) to the fluid outlet (402), and exits from the fluid outlet (402). The magnetic thrust bearing (1000) according to claim 1, wherein at least the first side surface of the thrust disc (110, 210) is configured to receive the fluid on the inner circumference (112, 212) of the thrust disc (110, 210) and to discharge the fluid on the outer circumference (114, 214) of the thrust disc (110, 210).

3. The magnetic thrust bearing (1000) has a first fluid inlet (401-1) for the fluid on the first side surface (101, 201) of the thrust disk (110, 210) and a second fluid inlet (401-2) for the fluid on the second side surface (102, 202) of the thrust disk (110, 210), The thrust disc (110, 210) comprises a first plurality of grooves (151-1) on the first side surface (101, 201) and a second plurality of grooves (151-2) on the second side surface (102, 202), The magnetic thrust bearing (1000) according to claim 2, wherein the first plurality of grooves (151-1) and the second plurality of grooves (151-2) are configured to pump the fluid as a result of the rotation of the rotor assembly (300).

4. The magnetic thrust bearing (1000) according to claim 1, wherein the thrust disc (110, 210) is provided with a first plurality of grooves and a second plurality of grooves on a first side surface (101, 201) and / or a second side surface (102, 202) of the thrust disc (110, 210), the first plurality of grooves being located in the inner area of ​​the side surface (101, 102) and the second plurality of grooves being located in the outer area of ​​the side surface (101, 102).

5. The magnetic thrust bearing (1000) according to claim 1, wherein the grooves (151, 251) are curved in shape.

6. The magnetic thrust bearing (1000) according to claim 1, wherein the grooves (151, 251) are configured such that at least a portion of the fluid flows in a preferred direction defined by the grooves (151, 251).

7. The magnetic thrust bearing (1000) according to claim 1, wherein the blade (252) is smaller than the thrust disk (210), and in particular, the height of the blade (252) is 5 to 15% of the diameter of the thrust disk (210).

8. The magnetic thrust bearing (1000) according to claim 1, wherein the width of the blade (252) is 70 to 100% of the thickness of the thrust disk (210).

9. The magnetic thrust bearing (1000) according to claim 1, wherein the blade (252) has a blade profile having a first concave surface and a second concave surface, the first concave surface being oriented toward a first side surface (201) of the thrust disk (210), and the second concave surface being oriented toward a second side surface (202) of the thrust disk (210).

10. The magnetic thrust bearing (1000) according to claim 1, wherein the blade (252) is attached to the thrust disk (210) in particular by a dovetail joint.

11. A rotating machine (2000) comprising a magnetic thrust bearing (1000) according to any one of claims 1 to 10, wherein the rotor assembly (300) of the magnetic thrust bearing (1000) is coupled to the shaft of the rotating machine (2000).

12. The rotating machine (2000) according to claim 11, wherein the rotating machine (2000) is an expander-compressor system.

13. The rotating machine (2000) according to claim 12, wherein the rotor assembly (300) of the magnetic thrust bearing (1000) is attached to a shaft (2100) that mechanically connects the expander (2800) of the expander-compressor system and the compressor (2900) of the expander-compressor system.

14. The rotating machine (2000) according to claim 11, wherein the magnetic thrust bearing (1000) is positioned within the casing (2200) of the machine, and the fluid outlet (402) of the magnetic thrust bearing (1000) is fluidly coupled to the inner chamber (2220) of the casing (2200).

15. The rotating machine (2000) according to claim 11, comprising a cooling system in which the fluid is recirculated in a closed-loop configuration solely by the magnetic thrust bearing (1000).

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