System and method for reducing parasitic thermal load from non-operating cryogenic cooler

Abstract

A superconducting machine system includes a superconducting electric machine. The superconducting machine system also includes a freezing container. The freezing container surrounds the superconducting machine. The superconducting machine system also includes a vacuum vessel wall surrounding the freezing vessel. The superconducting machine system even further includes a cryocooler coupled to the vacuum vessel wall, where the cryocooler is configured to cool the superconducting electric machine. The superconducting machine system also includes a system configured to remove helium gas from within the cryocooler housing when the cryocooler is switched to the non-operating state to reduce helium gas pressure within the cryocooler to minimize parasitic thermal load generated when the cryocooler is switched from the operating state to the non-operating state.

Description

[0001] Statement on Federal Government Funding for Research and Development

[0002] This invention was made with the support of the U.S. government under Contract No. U01EB027696, granted by the National Institutes of Health, Department of Health and Human Services. The government owns certain rights to the invention. Background Technology

[0003] The subject matter disclosed herein relates to a system and method for reducing parasitic heat loads from non-operating cryogenic coolers.

[0004] Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to visualize the detailed internal structures of a patient. An MRI system utilizes a superconducting magnet to generate a strong, uniform magnetic field in which the patient is placed. The superconducting magnet consists of individual superconducting magnet coils placed within a cryogenic liquid to maintain its superconductivity. The MRI system includes a cryocooler, which provides cooling to balance the thermal load on the superconducting magnet, ensuring no refrigerant loss. The cryocooler comprises a combination of a refrigerant accumulator and a displacement device, cooling the gaseous refrigerant and causing it to recondense.

[0005] When the cryocooler is turned off and not in operation, the heat load generated on the cryostat and magnet is much higher than expected. This is due to parasitic heat loads, which are transferred by means of high-power cryogenic convection flowing within the cryocooler and then transferred to the magnet through the cryocooler casing. Superconducting machines such as motors and generators also utilize cryocoolers. Summary of the Invention

[0006] The following provides an overview of some of the embodiments disclosed herein. It should be understood that these aspects are provided merely to give the reader a brief overview of these specific embodiments, and are not intended to limit the scope of this disclosure. In fact, this disclosure may cover various aspects that may not be set forth below.

[0007] In one embodiment, a superconducting machine system is provided. The superconducting machine system includes a superconducting machine. The superconducting machine system also includes a cryogenic container. The cryogenic container surrounds the superconducting machine. The superconducting machine system also includes a vacuum container wall that surrounds the cryogenic container. The superconducting machine system further includes a cryocooler coupled to the vacuum container wall, wherein the cryocooler is configured to cool the superconducting machine. The superconducting machine system also includes a system configured to remove helium from within the cryocooler housing when the cryocooler switches to a non-operating state to reduce the helium pressure within the cryocooler, thereby minimizing the parasitic heat load generated when the cryocooler switches from an operating state to a non-operating state.

[0008] In another embodiment, a system for reducing parasitic heat load from a non-operating cryogenic cooler is provided. The system includes a cryogenic cooler configured to be coupled to a vacuum container wall surrounding a cryogenic chamber that surrounds a superconducting machine, wherein the cryogenic cooler is configured to cool the superconducting machine. The system also includes a vacuum pump. The system further includes a controller and a processing system, the controller including a memory and the processing system including one or more processors. The controller is configured to provide control signals to the vacuum pump when the cryogenic cooler switches to a non-operating state, these control signals causing the vacuum pump to remove helium from within the cryogenic cooler housing to reduce the helium pressure within the cryogenic cooler, thereby minimizing the parasitic heat load generated when the cryogenic cooler switches from an operating state to a non-operating state.

[0009] In another embodiment, a method for reducing parasitic heat load from a non-operating cryogenic cooler is provided. The method includes switching the cryogenic cooler from an operating state to a non-operating state, wherein the cryogenic cooler is coupled to a vacuum container wall surrounding a cryogenic container that surrounds a superconducting machine, and wherein the cryogenic cooler is configured to cool the superconducting machine. The method further includes removing helium gas from within the cryogenic cooler housing using a vacuum pump when the cryogenic cooler is switched to the non-operating state to reduce the helium pressure within the cryogenic cooler, thereby minimizing the parasitic heat load generated when the cryogenic cooler switches from an operating state to a non-operating state. Attached Figure Description

[0010] These and other features, aspects, and advantages of this disclosure will be better understood when the following detailed description is read with reference to the accompanying drawings, in which the same symbols denote the same parts throughout the drawings, wherein:

[0011] Figure 1 This is a simplified block diagram of a superconducting machine system based on various aspects of this disclosure;

[0012] Figure 2A and Figure 2B Based on all aspects of this disclosure Figure 1 A cross-sectional view of a portion of a superconducting machine system;

[0013] Figure 3A and Figure 3B These are schematic diagrams of a cold head without a cold head sleeve attached to a liquefied cup with inlet and outlet pipes, and a cold head without a cold head sleeve attached to a superconducting magnet interface, respectively, according to various aspects of this disclosure.

[0014] Figures 4A-4C Based on all aspects of this disclosure Figure 1A cross-sectional view of a portion of a superconducting machine system, which has a system for reducing parasitic heat load (e.g., via a return line);

[0015] Figure 5 Based on all aspects of this disclosure Figure 1 And a cross-sectional view of a portion of the superconducting machine system in Figure 2, which has a system for reducing parasitic heat load (e.g., via a compressor);

[0016] Figure 6 This is a flowchart illustrating an embodiment of a method for reducing parasitic heat load from a non-operating cryogenic cooler, according to various aspects of this disclosure.

[0017] Figure 7 This is a flowchart of an embodiment of a method for (e.g., using monitoring) reducing parasitic heat load from a non-operating cryogenic cooler, according to various aspects of this disclosure;

[0018] Figure 8 This is a flowchart of an embodiment of a method for reducing parasitic heat load from a non-operating cryogenic cooler, according to various aspects of this disclosure;

[0019] Figure 9 These are example screenshots of temperatures in cryogenic devices and superconducting magnets according to various aspects of this disclosure; and

[0020] Figure 10 This is a schematic diagram of an example magnetic resonance system based on various aspects of this disclosure. Detailed Implementation

[0021] One or more specific implementations will be described below. To provide a concise description of these implementations, not all features of the actual implementation will be described in this specification. It should be understood that in the development of any such actual implementation, as in any engineering or design project, many implementation-specific decisions must be made to achieve the developer's specific objectives, such as complying with system-related and business-related constraints that may differ from implementation to implementation. Furthermore, it should be understood that such development efforts may be complex and time-consuming, but will in any case remain routine tasks of design, fabrication, and manufacturing for those skilled in the art who benefit from this disclosure.

[0022] When describing elements of various embodiments of the subject matter of this invention, the articles “a,” “an,” “the,” and “described” are intended to indicate the presence of one or more elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that additional elements may be present in addition to the listed elements. Furthermore, any numerical examples in the following discussion are intended to be non-limiting, and therefore the additional values, ranges, and percentages are within the scope of the disclosed embodiments.

[0023] While the various aspects of the following discussion are presented in the context of medical imaging, it should be understood that the disclosed techniques are not limited to this medical context. In fact, the examples and explanations provided in this medical context are merely for the purpose of facilitating explanation by providing examples of real-world implementations and applications. However, the techniques disclosed in this invention can also be used in other contexts, such as generating electricity using superconducting machines. Generally, this technique can be used in all superconducting machines that require the transfer of energy to / from environments at much higher temperatures. Although the disclosed techniques mention the use of helium, another cryogenic agent can be used.

[0024] This disclosure provides a system and method for reducing (e.g., minimizing or eliminating) parasitic heat loads from non-operating cryogenic coolers. Cryogenic coolers are used to cool superconducting machinery (e.g., superconducting coils or cold masses in magnetic resonance imaging systems, motors, generators, etc.). This disclosure is applicable to any machine utilizing superconducting wires and requiring cryogenic coolers (e.g., rotating and non-rotating (including cryogenic coolers), accelerator magnets, mine sweepers, cyclotrons, etc.). When switching from an operating cryogenic cooler to a non-operating cryogenic cooler, the heat load on the cryostat and superconducting machinery can increase due to parasitic heat loads transferred to the superconducting machinery through the cryogenic cooler housing via cryogenic convection and conduction operating within the cryogenic cooler. The parasitic heat problem is more severe when the cryogenic cooler is in an angled orientation (opposite to a vertical orientation). The disclosed embodiments reduce the helium pressure within the non-operating cryogenic cooler by removing helium. In response, the corresponding temperatures of the cryostat and superconducting machinery are reduced by decreasing the heat load. The disclosed embodiments achieve lower vaporization of standard cryogenic systems during cooler shutdown or transport. The disclosed implementation scheme enables the cryogenic system to achieve longer operating times. The disclosed implementation scheme reduces the total helium stock required for the cryogenic system, thereby reducing costs.

[0025] The disclosed embodiments include a superconducting machine system comprising a superconducting machine. The superconducting machine system also includes a cryogenic container surrounding the superconducting machine. The superconducting machine also includes a vacuum container wall surrounding the cryogenic container. The superconducting machine system further includes a cryocooler coupled to the vacuum container wall, wherein the cryocooler is configured to cool the superconducting machine. The superconducting machine system also includes a system configured to remove helium from the cryocooler housing when the cryocooler switches to a non-operating state to reduce the helium pressure within the cryocooler, thereby minimizing the parasitic heat load generated when the cryocooler switches from an operating state to a non-operating state.

[0026] In some embodiments, the system includes a vacuum pump configured to remove helium when the cryocooler is switched to a non-operating state until the helium pressure drops to a set threshold. In some embodiments, the set threshold is below 0.1 bar and above 10 bar. -1 millibars. In some implementations, the threshold is set between 10. -1 millibars and 10 -10 Between millibars. In some implementations, the threshold is set below 0.1 bar and above 10. -10 millibar.

[0027] In some embodiments, the vacuum pump is a low-vacuum pump. In some embodiments, the vacuum pump is a turbomachinery pump. In some embodiments, the superconducting machine is a superconducting magnet including superconducting coils. In some embodiments, the cryogenic cooler is oriented at an angle when coupled to the wall of the vacuum container. In some embodiments, the superconducting machine is a superconducting generator.

[0028] In some implementations, the system is configured to initially vent helium from the cryocooler to reduce the helium pressure to a first preset threshold when the cryocooler is switched to a non-operating state. Subsequently, a vacuum pump is configured to remove helium until the helium pressure drops to a second preset threshold below the first preset threshold.

[0029] In the disclosed embodiments, a system is provided for reducing (e.g., minimizing or eliminating) parasitic heat loads from a non-operating cryocooler. The system includes a cryocooler configured to be coupled to a vacuum container wall surrounding a cryogenic chamber that surrounds a superconducting machine, wherein the cryocooler is configured to cool the superconducting machine. The system also includes a vacuum pump. The system further includes a controller and a processing system, the controller including a memory and the processing system including one or more processors. The controller is configured to provide control signals to the vacuum pump when the cryocooler switches to a non-operating state, these control signals causing the vacuum pump to remove helium from within the cryocooler housing to reduce the helium pressure within the cryocooler, thereby minimizing the parasitic heat loads generated when the cryocooler switches from an operating state to a non-operating state.

[0030] In some implementations, the system includes one or more temperature sensors coupled to the cryogenic cooler. The controller is configured to receive feedback from the one or more temperature sensors, determine, based on the feedback, the amount of parasitic heat load generated when the cryogenic cooler switches from an operating state to a non-operating state, determine, based on the amount of parasitic heat load, a specific helium pressure to be achieved within the cryogenic cooler, and provide control signals to a vacuum pump that cause the vacuum pump to remove helium until the specific helium pressure is reached.

[0031] In some embodiments, the controller is configured to provide control signals to valves when the cryocooler switches to a non-operating state, causing an initial venting of helium from the cryocooler to reduce the helium pressure to a first set threshold, and subsequently, when the cryocooler switches to a non-operating state, to provide control signals to a vacuum pump, causing the vacuum pump to remove helium until the helium pressure drops below the first set threshold. In some embodiments, the controller is configured to provide control signals to the vacuum pump when the cryocooler switches to a non-operating state, causing the vacuum pump to remove helium until the helium pressure drops to a set threshold.

[0032] In the disclosed embodiments, a method for reducing (e.g., minimizing or eliminating) parasitic heat load from a non-operating cryocooler includes switching the cryocooler from an operating state to a non-operating state, wherein the cryocooler is coupled to a vacuum container wall surrounding a cryogenic container that surrounds a superconducting machine, and wherein the cryocooler is configured to cool the superconducting machine. The method further includes removing helium from within the cryocooler housing using a vacuum pump when the cryocooler is switched to the non-operating state to reduce the helium pressure within the cryocooler, thereby minimizing the parasitic heat load generated when the cryocooler switches from an operating state to a non-operating state.

[0033] In some embodiments, the method includes: providing control signals to valves that cause initial venting of helium from the cryocooler to reduce the helium pressure to a first preset threshold, and subsequently, when the cryocooler switches to a non-operating state, providing control signals to a vacuum pump that cause the vacuum pump to remove helium until the helium pressure drops to a second preset threshold below the first preset threshold. In some embodiments, the method also includes: providing control signals to the vacuum pump when the cryocooler switches to a non-operating state that cause the vacuum pump to remove helium until the helium pressure drops to a preset threshold.

[0034] In some implementations, the method includes: receiving feedback from one or more temperature sensors coupled to a cryogenic cooler; determining, based on the feedback, the amount of parasitic heat load generated when the cryogenic cooler switches from an operating state to a non-operating state; determining, based on the amount of parasitic heat load, a specific helium pressure to be achieved within the cryogenic cooler; and providing control signals to a vacuum pump that cause the vacuum pump to remove helium until the specific helium pressure is reached.

[0035] Figure 1 , Figure 2A and Figure 2B This is a simplified block diagram illustrating a superconducting machine system 20. The superconducting machine system 20 includes a superconducting machine 46. In some embodiments, the superconducting machine system is a superconducting magnet (e.g., a superconducting magnet in an MRI system or other types of systems). In some embodiments, the superconducting machine system is a superconducting generator or motor, or other types of superconducting systems, such as for superconducting RF cavities or others in accelerator magnet technology. In some embodiments, the superconducting machine 46 includes a set of superconducting coils and their supporting structures. The superconducting machine system 20 includes a container 22 (e.g., a cryogenic container) containing a liquid refrigerant (such as liquid helium). Thus, in this embodiment, container 22 is a helium container, which may also be referred to as a helium pressure vessel. Container 22 is surrounded by a vacuum container 24 and includes a thermal shield 26 surrounding container 22. The thermal shield 26 may be, for example, a thermally insulating radiation shield. A cold head 28 (which in various embodiments is a cryogenic cooler) extends through vacuum container 24 within a cold head sleeve 30 (which is coupled to the wall 25 of vacuum container 24). In some embodiments, the superconducting machine system 20 may include a plurality of cold heads 28. The cold ends of the cold heads 28 may be positioned within a cold head sleeve 30 without affecting the vacuum within the vacuum container 24. The cold heads 28 are inserted into (or received) and secured within the cold head sleeve 30 using any suitable means, such as one or more flanges and bolts, or other means known in the art. In some embodiments, the cold head sleeve 30 is Figure 2A The vacuum sleeve in the middle. Figure 2AIn this process, thermal contact 27 occurs between the heat shield 26 and the first stage 29 of the cold head 28. In some embodiments, the cold head sleeve 30 is in a helium atmosphere. In some embodiments, the cold head 28 operates with the cold head sleeve 30 filled with helium vapor, such as... Figure 2B As shown in the diagram. In some embodiments, the superconducting machine system 20 does not utilize, as... Figure 3A and Figure 3B The cold head vacuum sleeve depicted in the text. Figure 3A A cold head 28 is shown, which is attached with liquefaction fins 37 for recondensing helium or other refrigerants into a liquefaction cup 39 connected to an inlet and an outlet 43. Figure 3B A cold head 28 is shown that is directly attached to a superconducting magnet or other cold mass 45 without liquefying the refrigerant. Furthermore, as shown in Figure 4, the motor 32 of the cold head 28 is located outside the vacuum container 24. The cold head 28 includes a housing 33 that houses the piston drive mechanism and regenerator material (not shown), enabling the execution of a Gifford-McMahon (GM) cycle.

[0036] In some embodiments, the cold head 28 is a single-stage cooler (e.g., operating at 20 Kelvin (K) or higher). In some embodiments, the cold head 28 is a two-stage cooler. For example, the cold head 28 includes a first stage 29 and a second stage 31. The first stage 29 is coupled to a heat shield 26. The second stage 31 is coupled to a container 22. The cold head sleeve 30 includes an open end 34 leading into the helium container 22. Figure 2A and Figure 2B As shown, in various embodiments, the cold head 28 includes a recondenser 36 at its lower end, a portion of which extends through an open end 34 into the helium container 22 when the cold head 28 is inserted and received within the cold head sleeve 30. The recondenser 36 recondenses the helium vaporized from the helium container 22. Figure 2A and Figure 2B In the figure, the recondensed droplet is indicated by reference numeral 35. In some embodiments, such as Figure 2B As shown, passage 38 allows helium liquefaction to enter the open bottom 34 and then into the helium container 22.

[0037] In some embodiments, the superconducting device is a magnet, which in various embodiments is a superconducting magnet, disposed within a helium container 22 and controlled to acquire MRI image data during operation of an MRI system as described in more detail herein. Additionally, during operation of the MRI system, liquid helium within the helium container 22 of the MRI magnet system cools the superconducting magnet, which can be configured as a coil assembly as known. The superconducting magnet can be cooled to, for example, a superconducting temperature, such as 4.2 K or higher. The cooling process may include recondensing vaporized helium back into liquid by a recondenser 36 and returning it to the helium container 22. In some embodiments, during operation of the cold head 28, the temperature at the first stage 29 is approximately 45 Kelvin (K), and the temperature at the second stage 31 is approximately 4 K. The temperatures of the first stage 29 and the second stage 31 may differ.

[0038] The cold head 28 may include different internal components (e.g., stainless steel mesh, piston, rare earth balls, etc.) within the first stage 29 and the second stage 31. Figure 2A and Figure 2B As depicted, the cold head 28 is vertically oriented to the vacuum container 24 (i.e., the cold head is perpendicular to the wall 25 of the vacuum container 24 in a zero-degree orientation). When the cold head 28 switches from an operating state (i.e., the cold head 28 is in an on state cooling the superconducting machine 46) to a non-operating state (i.e., the cold head 28 is in a off state not cooling the superconducting machine 46), a higher-than-expected thermal load is imposed on the container 22 and the superconducting machine 46 (e.g., a superconducting magnet) due to parasitic heat load transferred to the superconducting machine 46 via the cold head housing 33 through the cryogenic current within the cold head 28. In some embodiments, the cold head 28 is arranged in an angled orientation (indicated by dashed line 60) relative to the wall 25 of the vacuum container 24. The angle of the cold head 28 can be any orientation other than that depicted in FIG. 2. In the angled orientation, the parasitic heat load can be higher than in the vertical orientation. As described in more detail below, the superconducting machine system 20 includes a system for reducing (e.g., minimizing or eliminating) parasitic heat load by removing helium from the cold head 28 when the cold head 28 is switched to a non-operating state, thereby reducing the helium pressure within the cold head 28.

[0039] Figure 4A yes Figure 1 and Figure 2A and Figure 2B A cross-sectional view of a portion of a superconducting machine system 20, which has a system 62 for reducing (e.g., minimizing or eliminating) parasitic heat loads (e.g., via a flexible return line). The superconducting machine system 20 is as follows... Figure 1 and Figure 2A and Figure 2BAs described herein. System 62 is configured to reduce the helium pressure within the cold head 28 (i.e., inside the cold head 28) by removing helium from the cold head 28, in order to reduce (e.g., minimize or eliminate) the parasitic heat load generated when the cold head 28 is switched to a non-operating state. System 62 includes passages 64 (return line) and 65 (supply line) connecting a compressor 67 (which compresses helium) to the cold head 28. System 62 includes a pump 66 (e.g., a vacuum pump) connected to passage 64 via passage 69. In some embodiments, pump 66 is a rough vacuum pump. The rough vacuum pump is configured to achieve an extension just above 10 - 3 A vacuum range of mbar. In some embodiments, pump 66 is a turbomechanical pump. The turbomechanical pump is configured to achieve a vacuum range of between 10 mbar. -1 mbar to 10 -10 The vacuum range between atmospheric pressure and 1 mbar is called rough vacuum. The vacuum range between 1 mbar and 10 mbar is also called rough vacuum. -3 A vacuum range between mbar and 10 mbar is called a medium vacuum. A vacuum can also be found between 10 mbar and 10 mbar. -3 mbar and less than 10 -12 The vacuum range from high to ultra-high to extremely high mbar.

[0040] Along passage 64 are valves 68 (e.g., a three-way valve) and 70 (e.g., a three-way valve). Valve 70 is positioned between valve 68 and pump 66 and compressor 67. The number and arrangement of valves can vary. In some embodiments, only a single valve may be used. Valve 68 is connected to passage 72.

[0041] System 62 includes a controller 74 and a nontransitory memory 78, the controller including a processing system 76 (e.g., one or more processors). Methods for controlling system 62 (i.e., reducing (e.g., minimizing or eliminating) parasitic heat loads) can be stored as executable instructions in the nontransitory memory 78 and executed by the processing system 76.

[0042] As an example, non-transitory memory 78 may store processor-executable software code or instructions (e.g., firmware or software) tangibly stored on a non-transitory computer-readable medium. Alternatively or additionally, non-transitory memory 78 may store data. As an example, memory 154 may include volatile memory (such as random access memory (RAM)) and / or non-volatile memory (such as read-only memory (ROM), flash memory, hard disk drive, or any other suitable optical, magnetic, or solid-state storage medium or combinations thereof). Furthermore, processing system 76 may include multiple microprocessors, one or more "general-purpose" microprocessors, one or more application-specific microprocessors, and / or one or more application-specific integrated circuits (ASICs), or some combination thereof. For example, processing system 76 may include one or more Reduced Instruction Set Computing (RISC) or Complex Instruction Set Computing (CISC) processors. Processing system 76 may include multiple processors and / or non-transitory memory 78 may include multiple memory devices.

[0043] Controller 74 is communicatively coupled to actuators of pump 66, compressor 67, valve 68, and valve 70. Controller 74 is configured to provide control signals to turn pump 66 on or off or to regulate the vacuum level of pump 66. Controller 74 is configured to control compressor 67. Controller 74 is configured to open or close valves 68 and 70. Controller 74 is configured to remove helium from cold head 28 to reduce (e.g., minimize or eliminate) parasitic heat loads generated during cold head 28 switching to a non-operating state. Specifically, in some embodiments, after cold head 28 switches to a non-operating state, controller 74 is configured to provide a control signal to open valve 68 when valve 70 is closed and valve 68 is closed, thereby blocking flow toward valve 70, thereby allowing flow along passage 72 to vent helium to the atmosphere, thereby reducing the helium pressure to a first set or desired threshold (e.g., 1 bar). When the helium pressure is reduced to the first set threshold, controller 74 is configured to provide a control signal to close a portion of valve 68 to block flow along passage 72. Subsequently, controller 74 is configured to provide a control signal to open a portion of valve 68, thereby enabling flow along passage 64 toward valve 70, and to open valve 70 in the portion connected to pump 66 when the portion connected to compressor 67 is closed, and to turn on pump 66 to apply a vacuum, thereby further reducing the helium pressure in cold head 28 to a second set or desired threshold. In some embodiments, if a coarse vacuum pump is used, the second set threshold may be less than 1 bar but just above 10 bar. -3 mbar. In some implementations, the second set threshold can be between 10 and 10. -1 mbar to 10 -10Between mbar. In some embodiments, the first set threshold and / or the second set threshold can vary. In some embodiments, instead of initially venting helium, the controller 74 can use the pump 66 to reduce the helium pressure to a set or desired threshold (via a return line).

[0044] In some embodiments, system 62 includes one or more temperature sensors 80 coupled to the cold head 28. A controller 74 is communicatively coupled to the temperature sensors 80 and configured to receive feedback from them. In some embodiments, controller 74 is configured to determine, based on feedback from the temperature sensors 80, the amount of parasitic heat load generated when the cold head 28 switches from an operating state to a non-operating state, determine a specific helium pressure to be achieved within the cold head 28 based on the amount of parasitic heat load, and provide control signals to pump 66 that cause pump 66 to remove helium until the specific helium pressure is reached.

[0045] In some implementations, system 62 includes one or more pressure sensors 82 within cold head 28. Controller 74 is configured to utilize feedback from the pressure sensors 82 to monitor helium pressure within cold head 28 during helium removal.

[0046] Figure 4B yes Figure 1 Figure 2 shows a cross-sectional view of a portion of a superconducting machine system 20, which has a system 62 for reducing (e.g., minimizing or eliminating) parasitic heat loads (e.g., via return lines or supply lines). The superconducting machine system 20 is as follows: Figure 1As shown in Figure 2, system 62 is configured to reduce the helium pressure within the cold head 28 (i.e., inside the cold head 28) by removing helium from the cold head 28, thereby reducing (e.g., minimizing or eliminating) the parasitic heat load generated when the cold head 28 is switched to a non-operating state. System 62 includes passages 64 (return line) and 65 (supply line) connecting a compressor 67 (which compresses helium) to the cold head 28. System 62 includes a pump 66 (e.g., a vacuum pump) connected to passage 64 via passage 69. Along passage 64 are valves 68 (e.g., a three-way valve) and 70 (e.g., a three-way valve). Valve 70 is positioned between valve 68 and pump 66 and compressor 67. The number and arrangement of valves can vary. In some embodiments, only a single valve may be used. Valve 68 is connected to passage 72. Valve 71 is positioned along passage 65. In some embodiments, after the cold head 28 is switched to a non-operating state, the controller 74 is configured to control valve 70 to close passage 64 and open passage 69 when valve 71 is closed. The controller 74 is then configured to turn on pump 66 to pump helium from the cold head housing 33 to a preset or desired threshold (e.g., 10⁻¹ mbar). In some embodiments, valves 70 and 71 are physically very close to the cold head, so the amount of helium to be pumped out and wasted is minimized. The majority of the helium remains stored in helium passages 64 and 65 and in compressor 67.

[0047] Figure 4C Another embodiment of the superconducting machine system 20 is shown, which has a vacuum chamber 90 connected to a helium channel 64 via a valve 70. The vacuum chamber is pre-evacuated to less than 10 using a service vacuum pump tool. -1 mbar vacuum pressure. In some embodiments, when the cold head 28 is switched to a non-operating state, the controller 74 is configured to control valve 70 to open passage 69 and vacuum chamber 90, so that helium gas inside the cryogenic cooler housing 33 is drawn into vacuum chamber 90. Therefore, the helium pressure inside cryogenic cooler housing 33 will decrease, and the heat load leaking from the non-operating cryogenic cooler to the superconducting machine 46 will be drastically reduced. In some embodiments, the volume of vacuum chamber 90 will be 10 to 100 times the volume of cryogenic cooler housing 33.

[0048] Figure 5 yes Figure 1 Figure 2 shows a cross-sectional view of a portion of a superconducting machine system 20, which has a system 62 for reducing (e.g., minimizing or eliminating) parasitic heat loads (e.g., via compressor 67). The superconducting machine system 20 is as follows... Figure 1As shown in Figure 2, system 62 is configured to reduce the helium pressure within cold head 28 by removing helium from the cold head 28, thereby reducing (e.g., minimizing or eliminating) the parasitic heat load generated when cold head 28 is switched to a non-operating state. System 62 includes passages 64 (return line) and 65 (supply line) connecting compressor 67 (which compresses helium) to cold head 28. In some embodiments, passages 64, 65 are rigid. In some embodiments, passages 64, 65 are flexible and modified to allow evacuation from the compressor end. Specifically, passage 64 is connected to a port on compressor 84 of cold head 28. System 62 includes a pump 66 (e.g., a vacuum pump) connected to compressor 67 via passage 84. In some embodiments, pump 66 is a rough vacuum pump. The rough vacuum pump is configured to achieve an extension just above 10°C. -3 A vacuum range of mbar. In some embodiments, pump 66 is a turbomechanical pump. The turbomechanical pump is configured to achieve a vacuum range of between 10 mbar. -1 mbar and 10 -10 The vacuum range between atmospheric pressure and 1 mbar is called rough vacuum. The vacuum range between 1 mbar and 10 mbar is also called rough vacuum. -3 Vacuum levels between mbar and 10 mbar are considered intermediate vacuum. Vacuum levels ranging from high to ultra-high to extremely high vacuum are defined as 10 mbar. -3 mbar and less than 10 -12 Within the range of mbar.

[0049] Along passage 64 are valve 68 (e.g., a three-way valve) and valve 70 (e.g., a two-way valve). Valve 70 is located between valve 68 and pump 66. The number and arrangement of valves can vary. In some embodiments, only a single valve may be used. Valve 68 is connected to passage 72.

[0050] System 62 includes a controller 74 and a nontransitory memory 78, the controller including a processing system 76 (e.g., one or more processors). Methods for controlling system 62 (i.e., reducing (e.g., minimizing or eliminating) parasitic heat loads) can be stored as executable instructions in the nontransitory memory 78 and executed by the processing system 76.

[0051] As an example, non-transitory memory 78 may store processor-executable software code or instructions (e.g., firmware or software) tangibly stored on a non-transitory computer-readable medium. Alternatively or additionally, non-transitory memory 78 may store data. As an example, memory 154 may include volatile memory (such as random access memory (RAM)) and / or non-volatile memory (such as read-only memory (ROM), flash memory, hard disk drive, or any other suitable optical, magnetic, or solid-state storage medium or combinations thereof). Furthermore, processing system 76 may include multiple microprocessors, one or more "general-purpose" microprocessors, one or more application-specific microprocessors, and / or one or more application-specific integrated circuits (ASICs), or some combination thereof. For example, processing system 76 may include one or more Reduced Instruction Set Computing (RISC) or Complex Instruction Set Computing (CISC) processors. Processing system 76 may include multiple processors and / or non-transitory memory 78 may include multiple memory devices.

[0052] Controller 74 is communicatively coupled to actuators of pump 66, compressor 67, valve 68, and valve 70. Controller 74 is configured to provide control signals to turn pump 66 on or off or to regulate the vacuum level of pump 66. Controller 74 is configured to open or close valves 68 and 70. Controller 74 is configured to control compressor 67. Controller 74 is configured to remove helium from cold head 28 to reduce (e.g., minimize or eliminate) parasitic heat loads generated during cold head 28 switching to a non-operating state. Specifically, in some embodiments, after cold head 28 switches to a non-operating state, controller 74 is configured to provide a control signal to open valve 68 when valve 70 is closed and valve 68 is closed, thereby blocking flow toward valve 70, thereby allowing flow along passage 72 to vent helium to the atmosphere, thereby reducing the helium pressure to a first set or desired threshold (e.g., 1 bar). When the helium pressure is reduced to the first set threshold, controller 74 is configured to provide a control signal to close a portion of valve 68 to block flow along passage 72. Subsequently, controller 74 is configured to provide a control signal to open a portion of valve 68, thereby enabling flow along passage 64 toward valve 70 (and compressor 67), opening valve 70, and activating pump 66 to apply a vacuum, thereby further reducing the helium pressure in cold head 28 to a second set or desired threshold by evacuating compressor 67. In some embodiments, if a coarse vacuum pump is used, the second set threshold may be less than 1 bar but just above 10 bar. -3 mbar. In some implementations, the second set threshold can be between 10 and 10. -1 mbar to 10 -10Between mbar. In some embodiments, the first set threshold and / or the second set threshold can vary. In some embodiments, instead of initially venting helium, the controller 74 can use the pump 66 to reduce the helium pressure to a set or desired threshold (via the vacuum compressor 67).

[0053] In some embodiments, system 62 includes one or more temperature sensors 80 coupled to the cold head 28. A controller 74 is communicatively coupled to the temperature sensors 80 and configured to receive feedback from them. In some embodiments, controller 74 is configured to determine, based on feedback from the temperature sensors 80, the amount of parasitic heat load generated when the cold head 28 switches from an operating state to a non-operating state, determine a specific helium pressure to be achieved within the cold head 28 based on the amount of parasitic heat load, and provide control signals to pump 66 that cause the pump to remove helium until the specific helium pressure is reached.

[0054] In some implementations, system 62 includes one or more pressure sensors 82 within cold head 28. Controller 74 is configured to utilize feedback from the pressure sensors 82 to monitor helium pressure within cold head 28 during helium removal.

[0055] Figure 6 This is a flowchart of an embodiment of method 86 for reducing (e.g., reducing or eliminating) parasitic heat loads from a non-operating cryogenic cooler (e.g., a cold head). One or more steps of method 86 may be illustrated by Figure 4 and... Figure 5 The system 62 (e.g., controller 74) and / or one or more components of the superconducting machine system 20 are executed.

[0056] Method 86 includes switching the cryocooler from an operational state to a non-operational state, wherein the cryocooler is coupled to a vacuum container wall that surrounds a cryogenic container that surrounds a superconducting machine, and wherein the cryocooler is configured to cool the superconducting machine (box 88). Method 86 also includes removing helium from within the cryocooler housing (e.g., using Figure 4 and...). Figure 5 System 62) in the system reduces the helium pressure within the cryogenic cooler, thereby reducing (e.g., minimizing or eliminating) the parasitic heat load generated when the cryogenic cooler switches from an operating state to a non-operating state (box 90).

[0057] Figure 7 This is a flowchart of an embodiment of method 92 for reducing (e.g., minimizing) or eliminating parasitic heat loads from non-operating cryogenic coolers (e.g., using monitoring). One or more steps of method 92 may be illustrated by Figure 4 and Figure 5 The system 62 (e.g., controller 74) and / or one or more components of the superconducting machine system 20 are executed.

[0058] Method 92 includes monitoring the temperature and pressure of the cryocooler (box 94). Monitoring the temperature and pressure of the cryocooler includes providing feedback to the controller from temperature and pressure sensors coupled to the cryocooler. Method 92 also includes switching the cryocooler from an operating state to a non-operating state, wherein the cryocooler is coupled to a vacuum container wall that surrounds a cryogenic container that surrounds a superconducting machine, and wherein the cryocooler is configured to cool the superconducting machine (box 96). Method 92 includes determining, based on feedback from the temperature sensors (e.g., at the controller), the amount of parasitic heat load generated when the cryocooler switches from an operating state to a non-operating state (box 98). Method 92 also includes determining, based on the amount of parasitic heat load, a specific helium pressure to be achieved within the cryocooler to reduce (e.g., minimize or eliminate) the parasitic heat load (box 100). Method 92 further includes providing a control signal (e.g., via a controller) (e.g., to a valve connected to a passage connected to the cryocooler or a return line to the cryocooler) to vent helium (e.g., to the atmosphere), thereby reducing the helium pressure from an initial level to a first lower level in the cryocooler (e.g., a preset or desired first threshold) (when the cryocooler is in an inoperable state) (box 102). After venting (when the cryocooler is in an inoperable state), method 92 includes providing control signals (e.g., via a controller) to a vacuum pump (e.g., a port connected to the compressor of the cryocooler or a return line connected to the cryocooler) that cause the vacuum pump to remove helium until a specific helium pressure in the cryocooler is reached (box 104). In some embodiments, the venting step may not occur, and only the vacuum pump is used to remove helium to achieve the specific helium pressure.

[0059] Figure 8 This is a flowchart of an embodiment of method 106 for reducing (e.g., minimizing or eliminating) parasitic heat loads from a non-operating cryogenic cooler (e.g., using a set threshold). One or more steps of method 106 may be illustrated by Figure 4 and Figure 5 The system 62 (e.g., controller 74) and / or one or more components of the superconducting machine system 20 are executed.

[0060] Method 106 includes monitoring the temperature and pressure of the cryocooler (box 108). Monitoring the temperature and pressure of the cryocooler includes providing feedback to the controller from temperature and pressure sensors coupled to the cryocooler. Method 106 also includes switching the cryocooler from an operational state to a non-operational state, wherein the cryocooler is coupled to a vacuum container wall that surrounds a cryogenic container that surrounds a superconducting machine, and wherein the cryocooler is configured to cool the superconducting machine (box 110). Method 92 also includes providing a control signal (e.g., via the controller) (e.g., to a valve coupled to a passage coupled to the cryocooler or a return line to the cryocooler) to vent helium (e.g., to the atmosphere), thereby reducing the helium pressure from an initial level to a first set or desired threshold in the cryocooler (when the cryocooler is in a non-operational state) (box 112). After venting (when the cryogenic cooler is in an inoperable state), method 106 includes (e.g., via a controller) providing control signals to a vacuum pump (e.g., a port connected to the compressor of the cryogenic cooler or a return line connected to the cryogenic cooler) that cause the vacuum pump to remove helium until the helium pressure in the cryogenic cooler drops to a second set threshold below a first set threshold (box 114).

[0061] Figure 9 This is an example screenshot 116 showing the temperatures in the cryostat and superconducting magnet of an MRI system. The top plot 118 depicts the temperature over time at different locations in the cryostat. The bottom plot 120 depicts the temperature over time at different locations in the superconducting magnet. The temperatures are during periods when the cryostat is not in operation. When helium is removed from the cryostat (using the technique described above), the temperature at the superconducting magnet shows a significant decreasing trend, as indicated by arrow 122. Similarly, at the same time points, the temperature at the cryostat also shows a significant decreasing trend, as shown in the top plot 118.

[0062] If the cryogenic cooler stops due to a malfunction or power outage, the pressure in the cryogenic cooler will also be displayed on the compressor pressure gauge, now showing static pressure instead of dynamic pressure. Static pressure is the pressure in the cryogenic cooler connected to the gas lines, as well as the pressure in the compressor. In principle, in the event of a power outage or compressor failure, the vacuum pump can operate using a battery pack, etc. The vacuum pump only needs to operate for a very short time because the volume of helium in the cryogenic cooler or in a cryogenic cooler connected to gas lines is very small.

[0063] It should be noted that superconducting machines (e.g., superconducting magnets, superconducting generators, etc.) can utilize multiple cryogenic coolers. In cases where more than one cryogenic cooler may be inactive, the parasitic heat load can be significantly increased (e.g., for three coolers with power loss, the parasitic heat flux increases threefold). Using the techniques described above, one or more cryogenic coolers can be deactivated while still allowing the superconducting machine to be utilized or maintained in a superconducting state.

[0064] As discussed herein, the disclosed systems and methods are used with wet systems (which are closed or sealed systems) in which the magnet is cooled by a bath or by using thermosiphon technology or other techniques with helium as the medium. The disclosed systems and methods can also be used where a cryocooler is directly mounted to the superconducting coil without involving the application of helium for cooling (i.e., conductive cooling systems, sealed systems, or completely dry systems). For these, cryocooler shutdown or failure is critical because if the cryocooler is not evacuated, a temperature surge occurs, leading to magnet loss of superconductivity (loss of the superconducting state).

[0065] It should be noted that while some implementation schemes can be described in conjunction with superconducting magnets used in MRI systems, various implementation schemes can be achieved by combining any type of system with a superconducting magnet. Superconducting magnets can be implemented in other types of medical imaging devices as well as non-medical imaging devices.

[0066] Therefore, various implementation schemes can be achieved by combining different types of superconducting coils (such as those used in MRI systems). For example, various implementation schemes can be implemented using superconducting coils to... Figure 10 The system is used in conjunction with the MRI system 200 shown. It should be understood that although system 200 is shown as a single-modal imaging system, various embodiments can be implemented or used in a multimodal imaging system. System 200 is shown as an MRI imaging system and can be combined with different types of medical imaging systems, such as computed tomography (CT), positron emission tomography (PET), single-photon emission computed tomography (SPECT), and ultrasound systems, or any other system capable of generating images, particularly of humans. Furthermore, various embodiments are not limited to medical imaging systems for imaging human subjects, but may include veterinary or non-medical systems for imaging non-human objects, luggage, etc.

[0067] refer to Figure 10The MRI system 200 typically includes an imaging section 202 and a processing section 204, the processing section of which may include a processor or other computing or controller device. The MRI system 200 includes a superconducting magnet 246 formed of coils within a gantry 206, which may be supported on a magnet coil support structure. A helium container 222 surrounds the superconducting magnet 246 and is filled with liquid helium. The liquid helium may be used to cool the cold head sheath and cold head housing and / or thermal shielding, as described in more detail herein.

[0068] Thermal insulation 212 is configured to surround the outer surface of the helium container 222 and the inner surface of the superconducting magnet 246. Multiple magnetic gradient coils 214 are disposed inside the superconducting magnet 246, and an RF transmit coil 216 is disposed within the multiple magnetic gradient coils 214. In some embodiments, the RF transmit coil 216 can be replaced by a transmit coil and a receive coil. Components within the pedestal 206 typically form the imaging section 202. It should be noted that although the superconducting magnet 246 is cylindrical, magnets of other shapes can be used.

[0069] The processing section 204 typically includes a controller 218, a main magnetic field control 220, a gradient field control 223, a memory 224, a display device 226, a transmit-receive (TR) switch 228, an RF transmitter 230, and a receiver 232.

[0070] In operation, the body of an object (such as a patient or a phantom to be imaged) is placed in an aperture 234 on a suitable support (e.g., a patient table). A superconducting magnet 246 generates a uniform and static main magnetic field Bo in the aperture 234. The intensity of the electromagnetic field in the aperture 234 and correspondingly in the patient's body is controlled by a controller 218 via a main magnetic field control 220, which also controls the supply of excitation current to the superconducting magnet 246.

[0071] Magnetic gradient coil 214 (which includes one or more gradient coil elements) is configured such that a magnetic gradient can be applied to the magnetic field Bo in the hole 234 within the superconducting magnet 246 in any one or more of the three orthogonal directions x, y, and z. Magnetic gradient coil 214 is excited by gradient field control 223 and also controlled by controller 218.

[0072] An RF transmitting coil 216, which may include multiple coils, is arranged to transmit magnetic pulses and / or optionally simultaneously detect MR signals from the patient (if a receiving coil element, such as a surface coil configured as an RF receiving coil, is also provided). The RF receiving coil can be of any type or configuration, for example, a separate receiving surface coil. The receiving surface coil can be an array of RF coils disposed within the RF transmitting coil 216.

[0073] The RF transmitting coil 216 and the receiving surface coil are selectively interconnected, respectively, to either the RF transmitter 230 or the receiver 232 via a TR switch 228. The RF transmitter 230 and the TR switch 228 are controlled by a controller 218 such that an RF field pulse or signal is generated by the RF transmitter 230 and selectively applied to the patient to excite magnetic resonance within the patient's body. When the RF excitation pulse is applied to the patient, the TR switch 228 is also actuated to disconnect the receiving surface coil from the receiver 232.

[0074] After the RF pulse is applied, the TR switch 228 is actuated again to disconnect the RF transmit coil 216 from the RF transmitter 230 and connect the receive surface coil to the receiver 232. The receive surface coil operates to detect or sense MR signals generated by excitation nuclei within the patient's body and transmits the MR signals to the receiver 232. These detected MR signals are then transmitted to the controller 218. The controller 218 includes, for example, a processor (e.g., an image reconstruction processor) that controls the processing of the MR signals to generate signals representing an image of the patient.

[0075] The processed signal representing the image is also transmitted to the display device 226 to provide a visual display of the image. Specifically, the MR signal fills or forms a k-space, which is then Fourier transformed to obtain a visual image. The processed signal representing the image is then transmitted to the display device 226.

[0076] The technical effects of the disclosed subject matter include reducing helium pressure within a non-operating cryogenic cooler via helium removal. In response, the corresponding temperatures of the cryostat and superconducting machinery decrease, thereby reducing the heat load. The technical effects of the disclosed subject matter also include achieving lower vaporization in standard cryogenic systems during cooler shutdown or transport. Furthermore, the technical effects of the disclosed subject matter include enabling longer operating times for cryogenic systems. Finally, the technical effects of the disclosed subject matter include reducing the total helium stock required for the cryogenic system, thereby lowering costs.

[0077] Referring to the technology presented herein and protected by the claims, and applying it to physical objects and concrete examples of practical nature, said practical nature explicitly improves the present art and is therefore not abstract, intangible, or purely theoretical. Furthermore, if any claim appended to the end of this specification contains one or more elements designated as “component for [performing]…the function” or “step for [performing]…the function,” such elements are intended to be interpreted according to 35 USC 112(f). However, for any claim containing elements designated in any other manner, such elements are not intended to be interpreted according to 35 USC 112(f).

[0078] This disclosure also provides support for a superconducting machine system comprising: a superconducting machine; a cryo-container surrounding the superconducting machine; a vacuum container wall surrounding the cryo-container; a cryocooler coupled to the vacuum container wall, wherein the cryocooler is configured to cool the superconducting machine; and a system configured to remove helium from within the cryocooler housing when the cryocooler switches to a non-operating state to reduce the helium pressure within the cryocooler, thereby minimizing parasitic heat loads generated when the cryocooler switches from an operating state to a non-operating state. In a first example of the superconducting machine system, the system includes a vacuum pump configured to remove helium when the cryocooler switches to a non-operating state until the helium pressure drops to a set threshold. In a second example of the system (optionally including the first example), the set threshold is less than 0.1 bar and greater than 10 bar. -10 Millibars. In a third example of the system (optionally including one or both of the first and second examples), the vacuum pump includes a rough vacuum pump. In a fourth example of the system (optionally including one or more or each of the first to third examples), the vacuum pump includes a turbomachinery pump. In a fifth example of the system (optionally including one or more or each of the first to fourth examples), the system is configured to first vent helium from the cryocooler to reduce the helium pressure to a first set threshold when the cryocooler is switched to a non-operating state, and then the vacuum pump is configured to remove helium until the helium pressure is reduced to a second set threshold below the first set threshold. In a sixth example of the system (optionally including one or more or each of the first to fifth examples), the system includes a pre-evacuation vacuum chamber configured to remove helium from the cryocooler housing when the cryocooler is switched to a non-operating state. In a seventh example of the system (optionally including one or more or each of the first to sixth examples), the superconducting machine includes a superconducting magnet. In an eighth example of the system (optionally including one or more or each of the first to seventh examples), the cryogenic cooler is oriented at an angle when coupled to the wall of the vacuum vessel. In a ninth example of the system (optionally including one or more or each of the first to eighth examples), the cryogenic cooler is a single-stage cooler. In a tenth example of the system (optionally including one or more or each of the first to ninth examples), the cooling medium for the superconducting machine is any other refrigerant. In an eleventh example of the system (optionally including one or more or each of the first to tenth examples), the superconducting machine includes a superconducting generator.

[0079] This disclosure also provides support for a system for reducing (e.g., reducing or eliminating) parasitic heat loads from a non-operating cryogenic cooler, the system comprising: a cryogenic cooler configured to be coupled to a vacuum container wall surrounding a cryogenic container surrounding a superconducting machine, wherein the cryogenic cooler is configured to cool the superconducting machine; a vacuum pump; and a controller including a memory and a processing system including one or more processors, wherein the controller is configured to provide control signals to the vacuum pump when the cryogenic cooler switches to a non-operating state, these control signals causing the vacuum pump to remove helium from the cryogenic cooler housing to reduce the helium pressure within the cryogenic cooler, thereby minimizing the parasitic heat loads generated when the cryogenic cooler switches from an operating state to a non-operating state. In a first example of the system, the system also includes one or more temperature sensors coupled to the cryogenic cooler, wherein the controller is configured to receive feedback from the one or more temperature sensors, determine based on the feedback the amount of parasitic heat load generated when the cryogenic cooler switches from an operating state to a non-operating state, determine based on the amount of parasitic heat load a specific helium pressure to be achieved within the cryogenic cooler, and provide control signals to a vacuum pump that cause the vacuum pump to remove helium until the specific helium pressure is reached. In a second example of the system (optionally including the first example), the controller is configured to provide control signals to a valve when the cryogenic cooler switches to a non-operating state, causing an initial discharge of helium from the cryogenic cooler to reduce the helium pressure to a first set threshold, and subsequently, when the cryogenic cooler switches to a non-operating state, provide control signals to the vacuum pump that cause the vacuum pump to remove helium until the helium pressure drops below the first set threshold to a second set threshold. In a third example of the system (optionally including one or both of the first and second examples), the controller is configured to provide control signals to the vacuum pump when the cryocooler switches to a non-operating state. These control signals cause the vacuum pump to remove helium until the helium pressure drops to a set threshold. In a fourth example of the system (optionally including one or more or each of the first to third examples), the set threshold is less than 0.1 bar and greater than 10 bar. -1 millibars. In the fourth example of the system (optionally including one or more or each of the first to fourth examples), the threshold is set between 10. -1 millibars and 10 -10 Between millibars. In a sixth example of the system (optionally including one or more or each of the first to fifth examples), the superconducting machine includes a superconducting magnet. In a seventh example of the system (optionally including one or more or each of the first to sixth examples), the superconducting machine includes a superconducting generator. In an eighth example of the system (optionally including one or more or each of the first to seventh examples), the vacuum pump includes a rough vacuum pump or a turbomachinery pump.

[0080] This disclosure also provides support for a method for (e.g., reducing or eliminating) parasitic heat loads from a non-operating cryocooler, the method comprising: switching the cryocooler from an operating state to a non-operating state, wherein the cryocooler is coupled to a vacuum container wall surrounding a cryogenic container surrounding a superconducting machine, and wherein the cryocooler is configured to cool the superconducting machine; and when the cryocooler is switched to a non-operating state, removing helium from the cryocooler housing using a vacuum pump to reduce the helium pressure within the cryocooler, thereby minimizing the parasitic heat loads generated when the cryocooler is switched from an operating state to a non-operating state.

[0081] This written description uses examples to disclose the subject matter of the invention, including best practices, and also enables those skilled in the art to practice the subject matter, including making and using any device or system and performing any included methods. The patent scope of this subject matter is defined by the claims and may include other examples that would occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they have structural elements that are not indistinguishable from the literal language of the claims, or if they include equivalent structural elements that have minor differences from the literal language of the claims.

Claims

1. A superconducting machine system, the superconducting machine system comprising: Superconducting machines; A freezing container that surrounds the superconducting machine; Vacuum container wall, the vacuum container wall surrounding the freezing container; A cryogenic cooler, the cryogenic cooler being connected to the wall of the vacuum container, wherein the cryogenic cooler is configured to cool the superconducting machine; and The system is configured to remove helium from the cryocooler housing when the cryocooler switches to a non-operating state to reduce the helium pressure within the cryocooler, thereby minimizing the parasitic heat load generated when the cryocooler switches from the operating state to the non-operating state.

2. The superconducting machine system of claim 1, wherein the system includes a vacuum pump configured to remove the helium gas when the cryogenic cooler switches to the non-operating state, until the helium gas pressure drops to a set threshold.

3. The superconducting machine system of claim 2, wherein the set threshold is below 0.1 bar and above 10 bar. -10 millibar.

4. The superconducting machine system according to claim 2, wherein the vacuum pump includes a rough vacuum pump.

5. The superconducting machine system of claim 2, wherein the vacuum pump comprises a turbomachinery pump.

6. The superconducting machine system of claim 2, wherein the system is configured to first discharge helium from the cryocooler to reduce the helium pressure to a first preset threshold when the cryocooler switches to the non-operating state, and the vacuum pump is subsequently configured to remove the helium until the helium pressure is reduced to a second preset threshold below the first preset threshold.

7. The superconducting machine system of claim 1, wherein the superconducting machine system includes a pre-evacuation chamber configured to remove helium from the cryocooler housing when the cryocooler switches to the non-operating state.

8. The superconducting machine system of claim 1, wherein the superconducting machine comprises a superconducting magnet.

9. The superconducting machine system of claim 1, wherein the cryogenic cooler is oriented at an angle when connected to the wall of the vacuum container.

10. The superconducting machine system of claim 1, wherein the cryogenic cooler is a single-stage cooler.

11. The superconducting machine system of claim 1, wherein the cooling medium used in the superconducting machine system is any other refrigerant.

12. The superconducting machine system of claim 1, wherein the superconducting machine comprises a superconducting generator.

13. A system for reducing parasitic heat load from a non-operating cryogenic cooler, the system comprising: A cryogenic cooler configured to be coupled to a vacuum container wall that surrounds a cryogenic container that surrounds a superconducting machine, wherein the cryogenic cooler is configured to cool the superconducting machine. Vacuum pump; and A controller, including a memory and a processing system including one or more processors, wherein the controller is configured to provide a control signal to the vacuum pump when the cryogenic cooler switches to a non-operating state, the control signal causing the vacuum pump to remove helium from the cryogenic cooler housing to reduce the helium pressure within the cryogenic cooler, thereby minimizing the parasitic heat load generated when the cryogenic cooler switches from the operating state to the non-operating state.

14. The system of claim 13, further comprising one or more temperature sensors coupled to the cryogenic cooler, wherein the controller is configured to receive feedback from the one or more temperature sensors, determine, based on the feedback, the amount of the parasitic heat load generated when the cryogenic cooler switches from the operating state to the non-operating state, determine, based on the amount of the parasitic heat load, a specific helium pressure to be achieved within the cryogenic cooler, and provide the control signal to the vacuum pump, the control signal causing the vacuum pump to remove the helium until the specific helium pressure is reached.

15. The system of claim 13, wherein the controller is configured to provide the control signal to a valve when the cryogenic cooler switches to a non-operating state, the control signal causing an initial discharge of helium from the cryogenic cooler to reduce the helium pressure to a first preset threshold, and subsequently, when the cryogenic cooler switches to a non-operating state, to provide the control signal to a vacuum pump, the control signal causing the vacuum pump to remove the helium until the helium pressure is reduced to a second preset threshold below the first preset threshold.

16. The system of claim 13, wherein the controller is configured to provide the control signal to the vacuum pump when the cryogenic cooler is switched to a non-operating state, the control signal causing the vacuum pump to remove the helium gas until the helium gas pressure drops to a set threshold.

17. The system of claim 16, wherein the set threshold is less than 0.1 bar and greater than 10 bar. -10 millibar.

18. The system of claim 17, wherein the set threshold is between 10 -1 millibars and 10 -10 Between milligrams.

19. The system of claim 13, wherein the superconducting machine comprises a superconducting magnet.

20. The system of claim 13, wherein the superconducting machine comprises a superconducting generator.

21. The system of claim 13, wherein the vacuum pump comprises a rough vacuum pump or a turbomachinery pump.

22. A method for reducing parasitic heat load from a non-operating cryogenic cooler, the method comprising: Switching a cryogenic cooler from an operational state to a non-operational state, wherein the cryogenic cooler is coupled to a vacuum container wall that surrounds a cryogenic container that surrounds a superconducting machine, and wherein the cryogenic cooler is configured to cool the superconducting machine; and When the cryogenic cooler switches to the non-operating state, a vacuum pump is used to remove helium from the cryogenic cooler housing to reduce the helium pressure inside the cryogenic cooler, thereby minimizing the parasitic heat load generated when the cryogenic cooler switches from the operating state to the non-operating state.

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