Helium gas supply device, helium liquefaction device, and inspection method

Abstract

To prevent oil from entering a helium liquefier before the oil enters the helium liquefier, and to easily catch a symptom of the oil.SOLUTION: A helium gas feeder 10 for feeding helium gas to be liquefied to a helium liquefier 20 includes a gas passage 11 for flowing the helium gas to the helium liquefier 20, compressors 12A and 12B provided in the gas passage 11 for compressing the helium gas, and an active carbon filter 41 provided downstream of the compressors 12A and 12B in the gas passage 11. The activated carbon filter 41 is for inspecting whether or not oil is contained in the passing helium gas, and is provided so as to be able to inspect the presence or absence of oil adhesion to the activated carbon filter.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for removing oil from helium gas upstream of a helium liquefier when the helium gas is compressed by a compressor and supplied to the helium liquefier. [Background technology]

[0002] Conventionally, when helium gas is liquefied, the helium gas is compressed to a high pressure (e.g., 1.5 MPa) using a compressor, and the compressed helium gas is supplied to a helium liquefier. The helium liquefier cools the supplied compressed helium gas and expands the cooled compressed helium gas to liquefy the compressed helium gas. An apparatus for liquefying helium gas is described, for example, in Patent Document 1 listed below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-174377 [Patent Document 2] International Publication No. 2006 / 051622 Summary of the Invention [Problem to be solved by the invention]

[0004] The compressor has operating parts for compressing helium gas, and lubricating oil is supplied to these operating parts. An example of such a compressor is an oil-injected screw compressor. This screw compressor has a casing and multiple rotors as operating parts. The multiple rotors rotate while meshing with each other within the casing, compressing the supplied helium gas. Lubricating oil is supplied to these rotors to ensure smooth operation.

[0005] Therefore, the compressed helium gas from such a compressor contains oil. When helium gas containing oil is supplied to a helium liquefier, the cooling capacity of the helium liquefier, which is an expensive piece of equipment, is reduced and the liquefier breaks down. For example, if oil adheres to the heat exchanger that cools the helium gas in the helium liquefier, the cooling capacity of the heat exchanger is reduced. Furthermore, as the helium gas is cooled in the helium liquefier, the oil solidifies and clogs the flow path of the helium gas.

[0006] To solve this problem, for example, an oil separator that separates oil from helium gas compressed by a compressor is provided upstream of the helium liquefier (see, for example, Patent Document 2). However, if the oil separation function of this oil separator deteriorates, there is a possibility that oil will enter the helium liquefier.

[0007] Therefore, when helium gas to be liquefied is compressed by a compressor and supplied to a helium liquefier, it is desirable to detect signs of oil before it gets into the helium liquefier. For example, by detecting such signs, measures such as performing maintenance on an oil separator installed upstream of the helium liquefier can be taken before oil gets into the helium liquefier.

[0008] Therefore, an object of the present invention is to prevent oil from entering a helium liquefier and to easily detect signs of oil entering the helium liquefier before the oil actually enters the helium liquefier. [Means for solving the problem]

[0009] A first aspect of the present invention is a helium gas supply device that supplies helium gas to be liquefied to a helium liquefier, comprising: a gas flow path for flowing the helium gas to the helium liquefier; a compressor provided in the gas flow path and configured to compress the helium gas; an activated carbon filter provided in the gas flow path downstream of the compressor, The activated carbon filter is used to check whether the helium gas passing through it contains oil, and is provided so that it can be checked whether oil is attached to the activated carbon filter.

[0010] A second aspect of the present invention is a helium liquefaction apparatus comprising: The above-mentioned helium gas supply device; the helium liquefier; and a liquid helium container for storing the liquid helium liquefied by the helium liquefier.

[0011] A third aspect of the present invention is a method for inspecting the presence or absence of oil in helium gas supplied to the helium liquefier by the above-mentioned helium gas supply device, comprising: By inspecting the activated carbon filter for the presence or absence of oil, it is possible to inspect whether the helium gas supplied to the helium liquefier contains oil. [Effects of the Invention]

[0012] According to the present invention as described above, when helium gas to be liquefied is compressed by a compressor and supplied to a helium liquefier, it is possible to prevent oil from entering the helium liquefier and easily detect signs of oil entering the helium liquefier before the oil actually enters the helium liquefier. [Brief explanation of the drawings]

[0013] [Figure 1] 1 shows the configuration of a helium liquefaction device according to an embodiment of the present invention. [Figure 2] 2 shows an example of the configuration of the filter device in FIG. [Figure 3] 10 shows a modified example of the filter device. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the present invention will be described with reference to the drawings. In addition, common parts in the drawings are given the same reference numerals, and duplicated explanations will be omitted.

[0015] 1 shows the configuration of a helium liquefaction apparatus 100 according to an embodiment of the present invention. The helium liquefaction apparatus 100 includes a helium gas supply apparatus 10, a helium liquefier 20, and a liquid helium container 1. The helium gas supply apparatus 10 supplies helium gas to be liquefied to the helium liquefier 20. The helium liquefier 20 liquefies the helium gas supplied from the helium gas supply apparatus 10. The helium liquefied by the helium liquefier 20 is supplied to the liquid helium container 1 and stored therein.

[0016] (Configuration of helium gas supply device) The helium gas supply device 10 includes a gas flow path 11, compressors 12A and 12B, an oil separator 13, filter devices 14A and 14B (activated carbon filters 41), a differential pressure sensor 15, a determination unit 16, and a notification device 17.

[0017] The gas flow path 11 allows the helium gas to be liquefied to flow to the helium liquefier 20. The gas flow path 11 may be made up of a plurality of pipes. Note that the gas flow path 11 may also include parts other than the pipes.

[0018] In this embodiment, gas flow path 11 includes supply flow path 11a and recovery flow path 11b. Supply flow path 11a allows one or both of helium gas returned from helium liquefier 20 and newly supplied pure helium gas (hereinafter simply referred to as pure helium gas) (both in the example of FIG. 1 ) to flow to helium liquefier 20.

[0019] As shown in Fig. 1, supply flow path 11a extends from helium liquefier 20 (the downstream end of second flow path 22, which will be described later) and may pass through compressor 12A, oil separator 13, and activated carbon filter 41 (filter device 14A) in this order before reaching helium liquefier 20. The above-mentioned pure helium gas may be, for example, newly purchased gas, and may be supplied from gas cardle 2 via buffer tank 3 to a predetermined location in supply flow path 11a as shown in Fig. 1. This predetermined location is located downstream of compressor 12A.

[0020] Recovery flow path 11b allows helium gas recovered from a device that uses liquid helium (hereinafter simply referred to as recovered helium gas) to flow to helium liquefier 20. Here, the device that uses liquid helium may be, for example, an MRI (Magnetic Resonance Imaging) device or an NMR (Nuclear Magnetic Resonance) device. The recovered helium gas may be helium gas that has evaporated from liquid helium in the MRI device, NMR device, or the like.

[0021] Recovery flow path 11b, for example, allows the recovered helium gas to flow from a gas storage body 4 (e.g., a gas bag) that stores the recovered helium gas to helium liquefier 20. More specifically, the recovered helium gas flowing through recovery flow path 11b passes from gas storage body 4 through compressor 12B, helium dryer 5, activated carbon filter 41 (filter device 14B), and multiple heat exchangers 6 in this order, and then flows into helium liquefier 20. In the example of FIG. 1, the downstream end of recovery flow path 11b is connected to a predetermined location on supply flow path 11a. This predetermined location is located downstream of filter device 14A as shown in FIG. 1. The helium dryer 5 dries the recovered helium gas that passes through.

[0022] The multiple heat exchangers 6 cool the recovered helium gas by exchanging heat between the recovered helium gas and helium gas flowing through a branch flow path 7 extending from a helium liquefier 20 (a downstream location in a first flow path 21 described below). The branch flow path 7 branches off from the helium liquefier 20 (a downstream location in a first flow path 21 described below) and merges with the upstream end of the supply flow path 11a. As shown in FIG. 1, a gas curdle 8 may be provided in the flow path branching off from a location in the recovery flow path 11b downstream of the compressor 12B and upstream of the filter device 14B.

[0023] Compressors 12A and 12B are provided in the gas flow path 11 and compress the helium gas to be sent to the helium liquefier 20. In this embodiment, compressor 12A is provided in the supply flow path 11a that constitutes the gas flow path 11, and compressor 12B is provided in the recovery flow path 11b that constitutes the gas flow path 11. Each of compressors 12A and 12B has a part that operates to compress the helium gas, and lubricating oil is supplied to this operating part. Compressor 12A may be, for example, an oil-lubricated screw compressor. Screw compressor 12A has a casing and multiple rotors as operating parts. The multiple rotors rotate while meshing with each other within the casing, compressing the supplied helium gas. Lubricating oil is supplied to these rotors to facilitate operation. Compressor 12B may be a compressor other than an oil-lubricated screw compressor and may be configured so that the compressed helium gas is less likely to contain oil.

[0024] As shown in FIG. 1, an oil separator 12b and a cooler 12c may be provided in the supply flow path 11a in association with the compressor 12A. The compressor 12A, the oil separator 12b, and the cooler 12c constitute the compression device 12. The oil separator 12b is provided downstream of the compressor 12A and separates oil from the helium gas compressed by the compressor 12A (hereinafter simply referred to as compressed helium gas). The oil separator 12b may be a container filled with a large amount of activated carbon. When the helium gas passes through the oil separator 12b, the oil adheres to the activated carbon and is separated. The cooler 12c may be a heat exchanger that indirectly cools the compressed helium gas by heat exchange with a refrigerant. This refrigerant may be, for example, cooling water.

[0025] The oil separator 13 is provided downstream of the compressor 12A (compressor 12) in the supply flow path 11a and separates oil from the compressed helium gas. The oil separator 13 may include multiple oil separators 13a-13b that separate oil from the compressed helium gas. The multiple oil separators 13a-13b may include cyclone oil separators 13a and 13b. The cyclone oil separators 13a and 13b may have a known configuration (for example, the one described in JP 2011-005440 A). The multiple oil separators 13a-13b may also include an oil separator 13c that is provided downstream of the cyclone oil separator 13b and has a container filled with a large amount of activated carbon. When the helium gas passes through the oil separator 13c, the oil adheres to the activated carbon and is separated.

[0026] The activated carbon filters 41 of the filter devices 14A and 14B are respectively provided downstream of the compressors 12A and 12B in the gas flow path 11. That is, the filter device 14A (activated carbon filter 41) is provided downstream of the compressor 12A and the oil separation device 13 in the above-mentioned supply flow path 11a that constitutes the gas flow path 11, and the filter device 14B (activated carbon filter 41) is provided downstream of the compressor 12B in the recovery flow path 11b that constitutes the gas flow path 11.

[0027] The activated carbon filters 41 of the filter devices 14A and 14B are provided to inspect whether or not oil is contained in the passing helium gas. The activated carbon filters 41 are provided so that it is possible to inspect whether or not oil is adhering to the activated carbon filters 41.

[0028] An example configuration of filter device 14A is shown in FIG. 2. Filter device 14B may have the same configuration as filter device 14A (the configuration of FIG. 2). Hereinafter, the notation "filter devices 14A, 14B" and "14A, 14B" in FIG. 2 include both cases where it refers to filter device 14A and where it refers to filter device 14B. Note that FIG. 2 is a cross-sectional view of filter devices 14A, 14B taken along a plane including central axis C. Filter devices 14A, 14B are configured to include an activated carbon filter 41 and a container 42 that houses the activated carbon filter 41, as shown in FIG. 2.

[0029] The activated carbon filter 41 is a cartridge-type filter that can be removed from the container 42. This makes it possible to inspect (for example, visually) outside the container 42 whether or not oil is adhering to the activated carbon filter 41, for example, by removing the activated carbon filter 41 from the container 42 to the outside.

[0030] In this embodiment, the filter devices 14A and 14B are disposed at positions in the gas flow path 11 where the temperature of the helium gas is equal to or lower than room temperature. Here, room temperature may mean a temperature of 15°C or higher and 25°C or lower (e.g., 25°C).

[0031] In the example of Figure 1, filter devices 14A, 14B (activated carbon filter 41) are provided in an intermediate position in gas flow path 11 between oil separator 13 and helium liquefier 20, but filter device 14A (activated carbon filter 41) may also be positioned immediately before helium liquefier 20 in gas flow path 11.

[0032] Furthermore, filter devices 14A and 14B may be arranged, for example, in a room in which helium liquefaction apparatus 100 is installed, with the outer surface of container 42 exposed to the room. This facilitates the work of removing activated carbon filter 41 from inside container 42 and the work of storing activated carbon filter 41 (for example, a new replaced activated carbon filter 41) inside container 42.

[0033] The differential pressure sensor 15, the determination unit 16, and the notification device 17 may be provided for the activated carbon filter 41 (that is, the filter devices 14A and 14B), as shown in FIG.

[0034] Differential pressure sensor 15 detects the pressure difference between the pressure upstream of activated carbon filter 41 and the pressure downstream of activated carbon filter 41. Here, the pressure upstream of activated carbon filter 41 may be the pressure in pipes 11a1 and 11b1 connecting filter devices 14A and 14B from the upstream side, or may be the pressure at a position upstream of activated carbon filter 41 in container 42. The pressure downstream of activated carbon filter 41 may be the pressure in pipes 11a2 and 11b2 connecting filter devices 14A and 14B from the downstream side, or may be the pressure at a position downstream of activated carbon filter 41 in container 42. Note that pipes 11a1 and 11b1 constitute supply flow path 11a and recovery flow path 11b, respectively, and pipes 11a2 and 11b2 constitute supply flow path 11a and recovery flow path 11b, respectively.

[0035] The determination unit 16 receives the pressure difference detected by the differential pressure sensor 15 from the differential pressure sensor 15 and determines whether the pressure difference exceeds a predetermined threshold value. If the result of the determination is positive, the determination unit 16 outputs an abnormality detection signal to the notification device 17.

[0036] When the notification device 17 receives the abnormality detection signal, it notifies a person (e.g., a manager of the helium gas supply device 10) of the abnormal state in which the pressure difference has exceeded the threshold. For example, the notification device 17 may have a display that displays an indication of the abnormal state. Alternatively, the notification device 17 may have a speaker that generates an alarm sound that indicates the abnormal state.

[0037] (Example of filter device configuration) As shown in FIG. 2, the activated carbon filter 41 constituting the filter devices 41A and 41B has a filter body 41a and a holding mechanism 41b. The filter body 41a is made of activated carbon. The filter body 41a may be made of activated carbon alone, or may be made of activated carbon and other materials. The activated carbon forming the filter body 41a has the function of separating oil from the passing helium gas. That is, if the helium gas passing through the filter body 41a contains oil, the oil will adhere to the activated carbon forming the filter body 41a. The activated carbon forming the filter body 41a may be porous.

[0038] The filter body 41a has an inner circumferential surface 41a1 and an outer circumferential surface 41a2 that extend around the central axis C of the filter body 41a. For example, the filter body 41a may be formed in a cylindrical shape. The inner circumferential surface 41a1 defines an internal space 41a3. One end of the internal space 41a3 in a direction parallel to the central axis C (hereinafter simply referred to as the axial direction) is open so as to communicate with the gas inlet 42b1 of the filter device 14A, 14B. The other end of the internal space 41a3 in the axial direction is closed. In the example of FIG. 2, the other end of the internal space 41a3 in the axial direction is closed by a second holding member 41b2, which will be described later. However, the other end of the internal space 41a3 in the axial direction may also be closed by the filter body 41a. In this case, the second holding member 41b2, which will be described later, may be omitted.

[0039] The holding mechanism 41b has first and second holding members 41b1 and 41b2. The first and second holding members 41b1 and 41b2 may be plate-like members having an axial thickness. One axial end face of the filter body 41a is attached to the first holding member 41b1. In this case, the filter body 41a may be an integrally formed activated carbon. The first holding member 41b1 has a through-hole h that connects the internal space 41a3 to the gas inlet 42b1. The other axial end face of the filter body 41a is attached to the second holding member 41b2. As a result, the second holding member 41b2 closes the other axial end of the internal space 41a3.

[0040] The holding mechanism 41b may further include an inner holding member 41b3 and an outer holding member 41b4 extending to surround the central axis C of the filter body 41a. One axial end of each of the inner holding member 41b3 and the outer holding member 41b4 is connected to the first holding member 41b1, and the other axial end is connected to the second holding member 41b2. The filter body 41a is disposed between the inner holding member 41b3 and the outer holding member 41b4. In this case, activated carbon (e.g., multiple loosely packed activated carbon particles) serving as the filter body 41a may be packed between the inner holding member 41b3 and the outer holding member 41b4. The inner holding member 41b3 and the outer holding member 41b4 may have multiple holes through which helium gas can pass (e.g., a member forming a mesh of multiple holes or a member forming multiple slits of multiple holes).

[0041] The container 42 includes a container body 42a and a lid member 42b. The container body 42a has an inner surface (e.g., an inner peripheral surface) that defines an internal space 42a1 and an opening through which the filter body 41a is inserted and removed from the internal space 42a1. The lid member 42b is airtightly attached to the container body 42a to close the opening. For example, the flange portion 42a3 of the container body 42a and the outer peripheral portion of the lid member 42b are detachably and airtightly coupled to each other using a quick coupling or bolts (not shown), with the outer peripheral portion of the first holding member 41b1 and an O-ring (not shown) sandwiched between the flange portion 42a3 of the container body 42a and the outer peripheral portion of the lid member 42b. The O-ring may be disposed between the flange portion 42a3 and the outer peripheral portion of the first holding member 41b1 and between the outer peripheral portion of the first holding member 41b1 and the outer peripheral portion of the lid member 42b.

[0042] The cover member 42b has a through-hole formed therein as a gas inlet 42b1 for the filter devices 14A and 14B. The pipes 11a1 and 11b1 constituting the gas flow path 11 (the supply flow path 11a and the recovery flow path 11b) may be detachably connected to the gas inlet 42b1. For example, a fitting 43a is attached to the cover member 42b at the gas inlet 42b1. A pipe fitting 43b provided at the tip of the pipe 11a1 or 11b1 is detachably attached to the fitting 43a. For example, a nut N is attached to the outer periphery of the fitting 43a so as to be movable within a predetermined range in the axial direction. The nut N may be threaded onto a male thread formed on the outer periphery of the pipe fitting 43b and tightened to couple the pipes 43a and 43b. Furthermore, the nut N can be rotated in a loosening direction from this state to remove the pipe fitting 43b from the fitting 43a. However, other configurations may be used to removably couple fitting 43b to fitting 43a.

[0043] The container body 42a has a through-hole formed therein as a gas outlet 42a2 for the filter devices 14A and 14B. The pipes 11a2 and 11b2 constituting the gas flow path 11 (the supply flow path 11a and the recovery flow path 11b) may be detachably connected to the gas outlet 42a2. For example, a fitting 44a is attached to the container body 42a at the gas outlet 42a2. A pipe fitting 44b provided at the base end of the pipe 11a2 or 11b2 is detachably attached to the fitting 44a. For example, a nut N is attached to the outer periphery of the fitting 44a so as to be movable within a predetermined range in the axial direction. The nut N may be threaded onto a male thread formed on the outer periphery of the pipe fitting 44b and tightened to couple the pipes 44a and 44b. Furthermore, the nut N can be rotated in a loosening direction from this state to remove the pipe fitting 44b from the fitting 44a. However, fitting 44b may be removably coupled to fitting 44a in other configurations.

[0044] In such filter devices 14A and 14B, the cartridge-type activated carbon filter 41 can be removed from the container 42 by a simple operation. For example, the lid member 42b can be removed from the container body 42a, and the activated carbon filter 41 can be taken out from inside the container body 42a. Note that, in one example, when removing the lid member 42b from the container body 42a, the pipe fitting 43b can be removed from the fitting 43a, thereby removing the lid member 42b from the pipe 11a1. At this time, the container body 42a can also be removed from the pipe 11b1.

[0045] (Helium liquefier) The helium liquefier 20 includes a first flow path 21, a second flow path 22, a third flow path 23, a plurality of heat exchangers 24, a plurality of expansion turbines 25, and a JT valve 26. The first flow path 21 extends from the downstream end of the supply flow path 11 a to the liquid helium container 1 . The second flow path 22 is a flow path that allows the helium gas evaporated in the liquid helium container 1 to flow to the upstream end of the supply flow path 11a. The third flow path 23 branches off from the second flow path 22 at a midpoint of the second flow path 22 and joins the second flow path 22 at a midpoint of the second flow path 22. The plurality of heat exchangers 24 cools the high-pressure helium gas flowing through the first flow path 21 by exchanging heat with the low-temperature helium gas flowing through the second flow path 22. The multiple expansion turbines 25 adiabatically expand the helium gas flowing through the third flow path 23 to produce low-temperature, low-pressure helium. A JT valve (Joule-Thomson valve) 26 is provided at the downstream end of the first flow path 21, and expands the helium gas to liquefy it by the Joule-Thomson (JT) effect. The liquid helium thus liquefied is supplied to the liquid helium container 1.

[0046] (Effects of the embodiment) According to the above-described embodiment, the following effects (A) to (G) can be obtained.

[0047] (A) An activated carbon filter 41 is provided downstream of compressors 12A, 12B and upstream of helium liquefier 20 to inspect whether the passing helium gas contains oil. If the helium gas passing through activated carbon filter 41 contains oil, the oil will adhere to activated carbon filter 41. Activated carbon filter 41 is provided so that the presence or absence of oil adhering to activated carbon filter 41 can be inspected. Therefore, by inspecting whether oil is adhering to activated carbon filter 41, activated carbon filter 41 can prevent the oil from entering helium liquefier 20 before it actually does, and a person such as the manager of helium liquefier 100 can easily detect signs of oil adhering to activated carbon filter 41 from the oil adhering to activated carbon filter 41.

[0048] In this way, the inspection method for the helium gas supply device 10 described above inspects whether or not oil is present in the helium gas supplied to the helium liquefier 20 by inspecting whether or not oil is present on the activated carbon filters 41 of the filter devices 14A and 14B.

[0049] (B) In the filter devices 14A and 14B, the activated carbon filter 41 is a cartridge-type filter that can be removed from the container 42. Therefore, for example, the activated carbon filter 41 can be removed to the outside of the container 42, and the presence or absence of oil adhering to the activated carbon filter 41 can be inspected outside the container 42. Alternatively, with the cover member 42b removed from the container body 42a, the presence or absence of oil adhering to the activated carbon filter 41 can be inspected while it is still placed in the container body 42a.

[0050] (C) Because the filter device 14A is provided downstream of the oil separator 13, by inspecting whether or not there is oil adhering to the activated carbon filter 41 of the filter device 14A, it is also possible to know whether or not the oil separation function of the large oil separator 13 is normal. If oil is adhering to the activated carbon filter 41 of the filter device 14A, it can be known that extensive maintenance of the oil separator 13 is necessary.

[0051] In this way, in the inspection method for the helium gas supply device 10 described above, whether or not the oil separation device 13 is functioning normally is inspected by checking whether or not oil is attached to the activated carbon filter 41 of the filter device 14A.

[0052] (D) By providing the filter device 14B in the recovery flow path 11b, the activated carbon filter 41 can prevent oil from entering the recovered helium gas before it enters the helium liquefier 20, and signs of this can be easily detected from the oil adhering to the activated carbon filter 41.

[0053] (E) A differential pressure sensor 15 is provided to detect the pressure difference between the upstream and downstream sides of the activated carbon filter 41, and a determination unit 16 determines whether the pressure difference detected by the differential pressure sensor 15 exceeds a predetermined threshold value, and if the determination result is positive, an abnormality detection signal is output from the determination unit 16. This makes it possible to know that the activated carbon filter 41 may be clogged with adhering oil, and that it is necessary to inspect the activated carbon filter 41 for the presence or absence of adhering oil.

[0054] (F) Oil in helium gas adheres more easily to activated carbon at lower temperatures. Therefore, filter devices 14A and 14B are disposed in gas flow path 11 at positions where the temperature of the helium gas is below room temperature. Therefore, when helium gas contains oil, the oil can be more reliably adhered to activated carbon filter 41.

[0055] (G) Filter device 14A is disposed in supply flow path 11a immediately before helium liquefier 20. This allows activated carbon filter 41 to check for the presence of oil on the lowest possible temperature side, upstream of helium liquefier 20, and if the helium gas contains oil, the oil can be more reliably adhered to activated carbon filter 41.

[0056] The present invention is not limited to the above-described embodiment, and various modifications may be made within the scope of the technical concept of the present invention. For example, the helium gas supply device 10 according to the embodiment of the present invention does not need to have all of the above-described features, and may have only some of the above-described features.

[0057] In addition, any of the following modified examples may be adopted alone, or the modified examples may be adopted together. In this case, the points not described below are the same as those described above.

[0058] (Example of change) 3, the container 42 (e.g., the container body 42a) may have an inspection window 45 made of a transparent material (e.g., glass or plastic) through which the activated carbon filter 41 inside the container 42 can be seen from the outside of the container 42. This allows the presence or absence of oil adhering to the activated carbon filter 41 to be inspected (e.g., visually) through the inspection window 45 with the activated carbon filter 41 placed inside the container 42. In this case, it is preferable that the direction of gas flow in the container 42 be opposite to that in FIG. [Explanation of symbols]

[0059] 1 liquid helium container, 2 gas curdle, 3 buffer tank, 4 gas storage body (gas bag), 5 helium dryer, 6 heat exchanger, 7 branch flow path, 8 gas curdle, 10 helium gas supply device, 11 gas flow path, 11a supply flow path, 11a1, 11a2 piping, 11b recovery flow path, 12 compression device, 12A compressor (screw compressor), 12b oil separator, 12c cooler, 12B compressor, 13 oil separator, 13a to 13b oil separator, 14A, 14B filter device, 15 differential pressure sensor, 16 judgment unit, 17 notification device, 20 helium liquefier, 21 first flow path, 22 second flow path, 23 third flow path, 24 heat exchanger, 25 expansion turbine, 26 JT valve, 41 activated carbon filter, 41a Filter body, 41a1 inner peripheral surface, 41a2 outer peripheral surface, 41a3 internal space, 41b holding mechanism, 41b1 first holding member, 41b2 second holding member, 41b3 inner holding member, 41b4 outer holding member, 42 container, 42a container body, 42a1 internal space, 42a2 gas outlet (through hole), 42b cover member, 42b1 gas inlet (through hole), 43a joint, 43b pipe joint, 44a joint, 44b pipe joint, 45 inspection window, 100 helium liquefaction device, C central shaft, N nut, h through hole

Claims

1. A helium gas supply device that supplies helium gas to be liquefied to a helium liquefier, a gas flow path for flowing the helium gas to the helium liquefier; a compressor provided in the gas flow path and configured to compress the helium gas; an activated carbon filter provided in the gas flow path downstream of the compressor, The activated carbon filter is for inspecting whether oil is contained in the helium gas passing through it, and is provided so that the presence or absence of oil adhering to the activated carbon filter can be inspected. Helium gas supply device.

2. the activated carbon filter constitutes a filter device provided downstream of the compressor in the gas flow path, The filter device includes the activated carbon filter and a container that accommodates the activated carbon filter, The activated carbon filter is a cartridge-type filter that can be removed from the container, so that the presence or absence of oil on the activated carbon filter removed from the container can be inspected. The helium gas supply device according to claim 1 .

3. the activated carbon filter constitutes a filter device provided downstream of the compressor in the gas flow path, The filter device includes the activated carbon filter and a container that accommodates the activated carbon filter, The container has a container body and a lid member, the container body has an internal space in which the activated carbon filter is disposed, and the lid member is removably attached to the container body so as to close an opening that opens the internal space to the outside, By removing the lid member from the container body, the presence or absence of oil on the activated carbon filter in the internal space can be inspected through the opening. The helium gas supply device according to claim 1 .

4. the activated carbon filter constitutes a filter device provided downstream of the compressor in the gas flow path, The filter device includes the activated carbon filter and a container that accommodates the activated carbon filter, the container has an inspection window formed of a transparent material; The presence or absence of oil adhering to the activated carbon filter inside the container can be inspected from the outside of the container through the inspection window. The helium gas supply device according to claim 1 .

5. the gas flow path includes a supply flow path through which helium gas returned from the helium liquefier or newly supplied pure helium gas flows to the helium liquefier, the compressor and the activated carbon filter are provided in the supply flow path, an oil separation device that is provided in the supply flow path downstream of the compressor and upstream of the activated carbon filter and that separates oil from the helium gas; The helium gas supply device according to claim 1 .

6. the gas flow path includes a recovery flow path through which helium gas recovered from an apparatus that uses liquid helium flows to the helium liquefier, The compressor and the activated carbon filter are provided in the recovery flow path. The helium gas supply device according to claim 1 .

7. a differential pressure sensor for detecting a pressure difference between the upstream side and the downstream side of the activated carbon filter; a determination unit that determines whether the pressure difference detected by the differential pressure sensor exceeds a predetermined threshold value, and outputs an abnormality detection signal if the result of the determination is affirmative. The helium gas supply device according to claim 1 .

8. The activated carbon filter is disposed at a position in the gas flow path where the temperature of the helium gas is equal to or lower than room temperature. The helium gas supply device according to claim 1 .

9. the activated carbon filter is disposed in the supply flow path immediately before the helium liquefier; The helium gas supply device according to claim 5.

10. The helium gas supply device according to any one of claims 1 to 9, the helium liquefier; a liquid helium container for storing the liquid helium liquefied by the helium liquefier, Helium liquefaction device.

11. A method for inspecting the presence or absence of oil in helium gas supplied to the helium liquefier by the helium gas supply device according to any one of claims 1 to 9, comprising: By inspecting whether or not oil is attached to the activated carbon filter, it is inspected whether or not the helium gas supplied to the helium liquefier contains oil. Testing method.

12. 6. A method for inspecting the presence or absence of oil in helium gas supplied to the helium liquefier by the helium gas supply apparatus according to claim 5, comprising: Checking whether the oil separator is functioning properly by checking whether oil is attached to the activated carbon filter. Testing method.

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