Control system and control method

Abstract

To provide a technology to inhibit gas for lubrication supplied inside a housing of a bearing device from flowing out to the outside of the housing other than a normal discharge path.SOLUTION: A control system 1 includes: a bearing device 30 including a housing 31 and a thrust bearing 34 for supporting a rotation shaft 20 using gas for lubrication supplied inside the housing 31; a supply path 60 for supplying the gas for lubrication inside the housing 31; a discharge path 80 for discharging the gas for lubrication to the outside of the housing; a supply valve 70 provided in the supply path 60 for adjusting a flow rate of the gas for lubrication supplied inside the housing 31; and a control part 95 for controlling the flow rate of the gas for lubrication supplied inside the housing 31 using the supply valve 70 on the basis of information on an outflow state of the gas for lubrication to the outside of the housing 31 from a path different from the discharge path 80.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to control systems and the like. [Background technology]

[0002] BACKGROUND ART Conventionally, a bearing device (so-called gas bearing) that supports a rotating shaft using a lubricating gas supplied from the outside to the inside of a housing is known (see Patent Document 1).

[0003] Patent Document 1 discloses that a hydrostatic gas bearing is used to support the thrust load on the rotating shaft of the expansion turbine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2023 / 210014 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is a possibility that the lubricating gas supplied to the inside of the housing may flow out (i.e., leak) to the outside of the housing via a route other than the regular discharge route. For this reason, for example, in Patent Document 1, the lubricating process gas supplied to the inside of the housing flows out to the inlet side of the impeller of the expansion turbine perpendicular to the main flow, and takes a shortcut to the impeller side, which may result in an inappropriate decrease in the temperature of the process gas at the turbine outlet.

[0006] Therefore, in view of the above problems, the object is to provide a technology that can prevent the lubricating gas supplied inside the housing of a bearing device from leaking outside the housing through any route other than the normal exhaust route. [Means for solving the problem]

[0007] In order to achieve the above object, in one embodiment of the present disclosure, a bearing device including a housing and a support part that supports a rotating shaft using a lubricating gas supplied to the inside of the housing; a supply path for supplying the lubricating gas into the housing; an exhaust path for exhausting the lubricating gas to the outside of the housing; a flow rate adjusting unit that is provided in the supply path and adjusts the flow rate of the lubricating gas supplied to the inside of the housing; a first control unit that controls the flow rate of the lubricating gas supplied to the inside of the housing using the flow rate adjustment unit based on information regarding an outflow state of the lubricating gas to the outside of the housing through a path different from the exhaust path; A control system is provided.

[0008] In another embodiment of the present disclosure, A control method for a bearing device including a housing and a support part that supports a rotating shaft using lubricating gas supplied to the inside of the housing, a supply path that supplies the lubricating gas to the inside of the housing, a discharge path that discharges the lubricating gas to the outside of the housing, and a flow rate adjustment part that is provided in the supply path and adjusts the flow rate of the lubricating gas supplied to the inside of the housing, using the flow rate adjusting unit to control the flow rate of the lubricating gas supplied into the housing based on information about an outflow state of the lubricating gas to the outside of the housing through a path different from the exhaust path. A control method is provided. [Effects of the Invention]

[0009] According to the above-described embodiment, it is possible to prevent the lubricating gas supplied to the inside of the housing of the bearing device from leaking to the outside of the housing through a route other than the normal exhaust route. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a first example of a control system. [Figure 2] FIG. 10 is a diagram illustrating a second example of a control system. [Figure 3]FIG. 10 is a diagram illustrating a third example of a control system. [Figure 4] FIG. 10 is a diagram illustrating an example of a method for controlling a supply valve. [Figure 5] 10A and 10B are diagrams illustrating another example of a method for controlling a supply valve. [Figure 6] FIG. 1 is a diagram illustrating an example of the configuration of a hydrogen gas filling system. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment will be described with reference to the drawings.

[0012] [Example of control system 1] A first example of a control system 1 according to this embodiment will be described with reference to FIG.

[0013] FIG. 1 is a diagram illustrating a first example of a control system 1. As shown in FIG.

[0014] In the figure, some of the components of the expansion turbine 10 (specifically, the housing 15 and the housing 31) are shown in a longitudinal cross section, i.e., a cross section taken along a plane passing through the rotation axis AX and parallel to the rotation axis 20. The same applies to Figure 2 described below. Hereinafter, in this specification, the axial direction, radial direction, and circumferential direction based on the rotation axis AX of the expansion turbine 10 may be simply referred to as the "axial direction," the "radial direction," and the "circumferential direction."

[0015] The control system 1 includes an expansion turbine 10 , a supply line 60 , a supply valve 70 , a discharge line 80 , a pressure transducer 90 , and a control unit 95 .

[0016] The control system 1 controls the supply of lubricating gas (hereinafter referred to as "bearing gas" for convenience) to a bearing device 30 incorporated in the expansion turbine 10.

[0017] The expansion turbine 10 includes a housing 15, a rotating shaft 20, a bearing device 30, an impeller 40, and an impeller 50.

[0018] For example, as shown in Fig. 1, the expansion turbine 10 is disposed so that the rotation axis AX is aligned in the up-down direction (i.e., vertical direction). Alternatively, the expansion turbine 10 may be disposed so that the rotation axis AX is aligned in the horizontal direction.

[0019] The housing 15 accommodates in its internal space the components of the expansion turbine 10, including the rotating shaft 20, the bearing device 30, the impeller 40, and the impeller 50. The housing 15 has a pressure-resistant structure with a relatively large wall thickness between its outer and inner surfaces to ensure pressure resistance against the high-pressure process gas flowing inside.

[0020] The rotating shaft 20 is arranged so that its axis coincides with the rotation axis AX of the expansion turbine 10 .

[0021] An impeller 40 for expanding a process gas is attached to one end (the lower end in this example) of the rotating shaft 20. The process gas is, for example, hydrogen gas. Alternatively, the process gas may be helium gas, nitrogen gas, or air.

[0022] An impeller 50 is attached to the other end (the upper end in this example) of the rotating shaft 20, which compresses the process gas flowing in through the inlet path 45. This makes it possible to consume the rotational energy of the rotating shaft 20, which is driven by the process gas through the impeller 40.

[0023] The impeller 50 may be replaced with a brake fan for braking or a power generator, which also applies to a second example (FIG. 2) described later.

[0024] The bearing device 30 supports the radial load and thrust load on the rotating shaft 20 rotating at high speed.

[0025] The bearing device 30 includes a housing 31, a radial bearing 32, a collar 33, and a thrust bearing 34.

[0026] The housing 31 supports a radial bearing 32, a collar 33, and a thrust bearing .

[0027] In this example, the rotating shaft 20 passes through the housing 31 in the vertical direction. Also, as described above, the rotation axis AX of the expansion turbine 10 may be arranged along the horizontal direction, in which case the rotating shaft 20 passes through the housing 31 in the horizontal direction. An impeller 40 is attached to one end (in this example, the lower end) of the rotating shaft 20 exposed from one end (in this example, the lower end) of the housing 31, and an impeller 50 is attached to the other end (in this example, the upper end) of the rotating shaft 20 exposed from the other end (in this example, the upper end) of the housing 31.

[0028] In this example, labyrinth seals 31C and 31D are provided in the through holes at one end (the lower end in this example) and the other end (the upper end in this example) of the housing 31, through which the rotating shaft 20 passes. As a result, the labyrinth seal 31C can prevent the bearing gas inside the housing 31 from leaking through the through hole of the rotating shaft 20 into the impeller chamber in which the impeller 40 is disposed. Similarly, the labyrinth seal 31D can prevent the bearing gas inside the housing 31 from leaking through the through hole of the rotating shaft 20 into the impeller chamber in which the impeller 50 is disposed.

[0029] In this example, a labyrinth seal 40A is provided on the opposing surface (top surface in this example) of the impeller 40 that faces the housing. This allows the labyrinth seal 40A to prevent the bearing gas inside the housing 31 from leaking through the through-hole of the rotating shaft 20 into the impeller chamber in which the impeller 40 is disposed. Similarly, in this example, a labyrinth seal 50A is provided on the opposing surface (bottom surface in this example) of the impeller 50 that faces the housing. This allows the labyrinth seal 50A to prevent the bearing gas inside the housing 31 from leaking through the through-hole of the rotating shaft 20 into the impeller chamber in which the impeller 50 is disposed.

[0030] The radial bearing 32 supports a radial load on the rotating shaft 20. For example, as shown in Fig. 1, the radial bearing 32 is a tilting pad type radial bearing.

[0031] The radial bearing 32 is not limited to the tilting pad type, and various other types can be adopted.

[0032] In this example, two radial bearings 32 are provided, one at each end in the axial direction inside the housing 31.

[0033] The collar 33 is attached to the rotary shaft 20 and has a disk shape centered on the rotary shaft 20. The collar 33 is provided inside the housing 31 at the center in the axial direction.

[0034] The collar 33 is configured to be able to receive a reaction force (hereinafter referred to as a "thrust reaction force") generated by the thrust bearing 34 in response to the thrust load of the rotary shaft 20.

[0035] The thrust bearing 34 supports a thrust load on the rotary shaft 20. Specifically, the thrust bearing 34 generates a thrust reaction force on the collar 33.

[0036] The thrust bearing 34 is disposed so as to face the collar 33 in the axial direction. For example, as shown in Fig. 1, two thrust bearings 34 are provided, and each is disposed so as to be adjacent to both one end (in this example, the lower end) and the other end (in this example, the upper end) of the rotating shaft 20 when viewed from the collar 33.

[0037] For example, as shown in FIG. 1 , the thrust bearing 34 is a hydrostatic gas bearing. Specifically, the thrust bearing 34 has injection holes 34A that inject bearing gas toward the collar 33. For example, the injection holes 34A are provided at predetermined intervals in the circumferential direction. The injection holes 34A communicate with a supply path 31A provided in the housing 31 and with supply paths 60, 61 or supply paths 60, 62 connected to the supply path 31A, and bearing gas is supplied to the injection holes 34A from outside the expansion turbine 10. The bearing gas is, for example, the same type of gas as the process gas introduced into the expansion turbine 10 (specifically, the impellers 40, 50). In this case, as described below, the process gas before being introduced into the expansion turbine 10 is branched and supplied to the thrust bearing 34. Alternatively, the bearing gas may be a type of gas dedicated to the thrust bearing 34 that is different from the process gas introduced into the expansion turbine 10.

[0038] The injected bearing gas is discharged to the outside of the expansion turbine 10 through a through hole 31B provided at a location radially outward from the collar 33 in the housing 31 and through a discharge path 80 connected to the through hole 31B.

[0039] 1, the thrust bearing 34 may be a dynamic pressure gas bearing that supports the thrust load of the rotating shaft 20 by gas film pressure between it and the collar 33. In this case, the injection holes 34A are omitted. The thrust bearing 34 may also be a combination of both the dynamic pressure type and the static pressure type.

[0040] The injection holes 34A are provided on the surface of the thrust bearing 34 facing the collar 33, and are formed so that the injection direction of the bearing gas is in the axial direction. This allows the bearing gas injected from the injection holes 34A to generate a thrust reaction force in the collar 33. Furthermore, even if the rotating shaft 20 tilts due to runout or vibration of the rotating shaft 20, causing the collar 33 to approach the thrust bearing 34, the action of the injected bearing gas can suppress abnormal approach due to an increase in the tilt of the rotating shaft 20. As a result, contact between the collar 33 and the thrust bearing 34 can be suppressed.

[0041] Supply path 60 is a path for supplying bearing gas to bearing device 30. Supply path 60 branches into supply paths 61 and 62, which are connected to supply paths 31A corresponding to the two thrust bearings 34 arranged so as to sandwich collar 33 in the axial direction. Supply paths 60 to 62 include, for example, holes formed in housing 15 and pipes connected to housing 15.

[0042] The supply valve 70 is provided in the supply path 60. The supply valve 70 adjusts its opening in response to a command from the control unit 95, and can adjust the flow rate of the bearing gas into the housing 31 through the supply path 60. The supply valve 70 is, for example, a solenoid valve.

[0043] As described above, the exhaust path 80 is connected to the through-hole 31B, and is a path for exhausting the bearing gas injected into the housing 31 from the injection holes 34A to the outside of the housing 31. For example, the tip of the exhaust path 80 is open to the atmosphere. Furthermore, if the bearing gas is the same type of gas as the process gas, the exhaust path 80 may be connected to a process gas supply source. This allows the bearing gas to be reused as the process gas. The exhaust path 80 includes, for example, a hole formed in the housing 15 or a pipe connected to the housing 15.

[0044] The pressure transducer 90 converts the pressure of the bearing gas inside the housing 31 into an electric signal (hereinafter referred to as a "detection signal") and outputs it. For example, the housing 31 is provided with a through-hole 31E that passes through the inside and outside of the housing 31, and the pressure transducer 90 senses the pressure inside the housing 31 through the through-hole 31E. The pressure transducer 90 may be provided inside the through-hole 31E or at the outlet of the through-hole 31E on the outside of the housing 31, or may be provided in a pipe or the like that communicates with the through-hole 31E on the outside of the housing 31.

[0045] The control unit 95 outputs a command signal to the supply valve 70 based on the detection signal output from the pressure transducer 90, thereby controlling the opening degree of the supply valve 70. The functions of the control unit 95 are realized by any hardware or a combination of any hardware and software. The control unit 95 is, for example, a pressure indication controller (PIC).

[0046] For example, the control unit 95 performs feedback control of the opening of the supply valve 70 so that the pressure P inside the housing 31, which corresponds to the detection signal received from the pressure transducer 90, becomes equal to the control set value Ps. The control set value Ps is specified to be relatively low within a range equal to or greater than the lower limit value Plim of the pressure P required for the thrust bearing 34 to support the thrust load on the rotating shaft 20. This allows the control unit 95 to prevent the pressure of the bearing gas inside the housing 31 from becoming excessive and leaking the bearing gas to the outside of the housing 31 through a path other than the discharge path 80 (hereinafter, for convenience, referred to as a "leakage path"). For example, an example of a path other than the discharge path 80 is the through-hole of the rotating shaft 20 in the housing 31. This is because, even if labyrinth seals 31C, 31D, 40A, and 50A are provided, it is not possible to completely prevent the bearing gas from leaking through the through-hole of the rotating shaft 20 in the housing 31 when the pressure inside the housing 31 becomes excessive.

[0047] The control set value Ps is determined in advance, for example, taking into consideration the expected pressure on the outlet side of the leakage path. For example, if the leakage path is a through-hole of the rotary shaft 20 on the impeller 40 side in the casing 31, the control set value Ps is determined in advance based on the expected pressure range of the process gas at the inlet of the impeller 40. Alternatively, the control set value Ps may be determined by sequentially calculating based on sequentially acquired actual measured values ​​of the pressure on the outlet side of the leakage path. For example, if the leakage path is a through-hole of the rotary shaft 20 on the impeller 40 side in the casing 31, the control set value Ps is sequentially calculated based on the actual measured values ​​of the process gas at the inlet of the impeller 40 (e.g., the outlet of the inlet nozzle 41). Specifically, the control set value Ps is sequentially calculated with respect to an expansion ratio based on the actual measured values ​​of the process gas pressure at each of the inlet and outlet of the impeller 40, taking into consideration the degree of reaction of the expansion turbine 10. This allows the control unit 95 to prevent the pressure of the bearing gas inside the housing 31 from becoming excessively large compared to the pressure of the process gas at the inlet of the impeller 40. Therefore, the control unit 95 can prevent the bearing gas from flowing out from the through-hole on one end (in this example, the lower end) side of the rotating shaft 20 in the housing 31 to the inlet side of the impeller 40.

[0048] Because the main flow of process gas flowing into impeller 40 and the flow of bearing gas flowing out from the through hole on one end side of rotating shaft 20 in casing 31 are perpendicular to each other, there is a possibility that the bearing gas flowing out from casing 31 will take a shortcut to the outlet side without flowing into impeller 40. As a result, the process gas leaking from casing 31 as bearing gas will merge with the process gas flowing out from impeller 40, causing a rise in temperature and making it impossible to appropriately reduce the outlet temperature of expansion turbine 10. In response to this, the control unit 95 adjusts the pressure inside casing 31 so that it is relatively lower than the expected pressure range at the inlet of impeller 40, thereby suppressing an increase in the outlet temperature of expansion turbine 10 and maintaining the outlet temperature of expansion turbine 10 within an appropriate range.

[0049] [Second example of control system] Next, a second example of the control system 1 according to this embodiment will be described with reference to FIG.

[0050] In this example, the same or corresponding configurations as those in the first example (FIG. 1) are given the same symbols, and the explanation will focus on the parts that are different from the first example, and explanations of the parts that are the same or corresponding to those in the first example may be omitted.

[0051] FIG. 2 is a diagram illustrating a second example of the control system 1. As shown in FIG.

[0052] In this example, the control system 1 differs from the first example described above mainly in that it includes a pressure transducer 91 in addition to the pressure transducer 90, and in that the configuration of the control unit 95 is changed.

[0053] The pressure transducer 91 converts the pressure of the process gas at the inlet of the impeller 40 into an electric signal (hereinafter referred to as a "detection signal") and outputs it. For example, the housing 15 is provided with a through-hole 15A that passes through to the outlet of the inlet nozzle 41 for the impeller 40, and the pressure transducer 91 senses the pressure of the process gas at the inlet of the impeller 40 through the through-hole 15A. The pressure transducer 91 may be provided inside the through-hole 15A or at the outlet of the through-hole 15A outside the housing 15, or may be provided in a pipe or the like that communicates with the through-hole 15A outside the housing 15.

[0054] The control unit 95 includes control units 95A to 95C.

[0055] The control unit 95A outputs a command signal for controlling the opening degree of the supply valve 70 based on the detection signals output from the pressure transducers 90 and 91. The function of the control unit 95A is realized by any hardware or a combination of any hardware and software. The control unit 95A is, for example, a differential pressure indication controller (DPIC).

[0056] For example, the control unit 95A outputs a control command to feedback-control the opening of the supply valve 70 so that the differential pressure ΔP between the bearing gas pressure P inside the housing 31, which corresponds to the detection signals received from the pressure transducers 90 and 91, and the process gas pressure P1 at the inlet of the impeller 40, becomes a control set value ΔPs. The control set value ΔPs is determined in advance based on theoretical formulas, experimental data, computer simulation data, etc., so as to minimize leakage of the bearing gas through the through-hole of the rotating shaft 20 on the impeller 40 side of the housing 31.

[0057] The control unit 95B outputs a command signal for controlling the opening degree of the supply valve 70 based on the detection signal output from the pressure transducer 90. The functions of the control unit 95B are realized by any hardware or a combination of any hardware and software. The control unit 95B is, for example, a pressure indicating controller (PIC).

[0058] Specifically, the control unit 95B outputs a control command to feedback control the opening degree of the supply valve 70 so that the pressure P of the bearing gas inside the housing 31, which corresponds to the detection signal input from the pressure converter 90, becomes the lower limit value Plim.

[0059] The control unit 95C selects one of the command signals from the control units 95A and 95B that corresponds to a larger opening of the supply valve 70, and outputs the selected command signal to the supply valve 70. In this way, the control unit 95C uses the command signal from the control unit 95A to suppress leakage of bearing gas from the through-hole on the impeller 40 side of the rotary shaft 20 in the housing 31, while maintaining the function of the thrust bearing 34. It is possible to ensure the bearing gas pressure inside the housing 31. The function of the control unit 95C can be realized by any hardware or any combination of hardware and software. The control unit 95C is, for example, a high selector circuit.

[0060] The functions of the control units 95A to 95C may be realized by using one control unit (hardware).

[0061] In this way, in this example, the control unit 95 controls the supply valve 70 to control the differential pressure ΔP between the bearing gas pressure P inside the casing 31 and the process gas pressure P1 at the inlet of the impeller 40. Therefore, the control unit 95 can control the differential pressure ΔP, which directly affects leakage of bearing gas through the through-hole on the impeller 40 side of the rotating shaft 20 in the casing 31. Therefore, the control unit 95 can more reliably suppress leakage of bearing gas from the casing 31 to the inlet side of the impeller 40.

[0062] [Third example of control system] Next, a third example of the control system 1 according to this embodiment will be described with reference to FIGS.

[0063] In this example, the same symbols are used for the same or corresponding configurations as the first example (FIG. 1) and second example (FIG. 2) described above, and the explanation will focus on the parts that are different from the first and second examples described above, and explanations of the parts that are the same or corresponding to the first and second examples described above may be omitted.

[0064] Fig. 3 is a diagram showing a third example of the control system 1. Fig. 4 is a diagram showing an example of a method for controlling the supply valve 70. Fig. 5 is a diagram showing another example of a method for controlling the supply valve 70.

[0065] In this example, the control system 1 differs from the first and second examples described above mainly in that a pressure gauge 92 and flow meters 93 and 94 are provided, the configuration of the control unit 95 is changed, and a control unit 96 is added.

[0066] The pressure gauge 92 measures the pressure Pin of the bearing gas flowing through the supply path 60, i.e., the pressure Pin of the bearing gas supplied to the bearing device 30 through the supply path 60. A signal corresponding to the measurement value of the pressure Pin obtained by the pressure gauge 92 is input into the differential pressure calculator 95D via a predetermined communication line such as a one-to-one communication line or a local area network (LAN).

[0067] The flow meter 93 measures the flow rate Fin of the bearing gas flowing through the supply path 60, i.e., the flow rate Fin of the bearing gas supplied to the bearing device 30 through the supply path 60. The flow rate Fin is, for example, the mass flow rate of the bearing gas in the supply path 60. A signal corresponding to the measurement value of the flow rate Fin obtained by the flow meter 93 is input into the flow rate difference calculator 95F via a predetermined communication line such as a one-to-one communication line or a local network (LAN).

[0068] The flow meter 94 measures the flow rate Fout of the bearing gas flowing through the discharge path 80, i.e., the flow rate Fout of the bearing gas discharged from the bearing device 30 through the discharge path 80. The flow rate Fout is, for example, the mass flow rate of the bearing gas in the discharge path 80. A signal corresponding to the measurement value of the flow rate Fout obtained by the flow meter 94 is input into a flow rate difference calculator 95F via a predetermined communication line such as a one-to-one communication line or a local network (LAN).

[0069] The control unit 95 controls the pressure and flow rate of the bearing gas supplied to the housing 31 by adjusting the opening of the supply valve 70 based on the outputs of the pressure converter 90 and the pressure meter 92, and the outputs of the flow meter 93 and the flow meter 94. For example, as shown in Fig. 3, the control unit 95 includes a differential pressure calculator 95D, a comparator 95E, a flow rate difference calculator 95F, a comparator 95G, and a high selector 95H.

[0070] The differential pressure calculator 95D calculates the differential pressure ΔP between the pressure P of the bearing gas inside the housing 31 and the pressure Pin of the bearing gas supplied to the inside of the housing 31 through the supply path 60 based on the outputs of the pressure converter 90 and the pressure gauge 92.

[0071] The function of the differential pressure calculator 95D is realized by any hardware or any combination of hardware and software. The function of the differential pressure calculator 95D is realized, for example, by a hardware calculation circuit. Alternatively, the differential pressure calculator 95D may be configured mainly with a computer including a CPU, a memory device, an auxiliary storage device, etc., and the function of the differential pressure calculator 95D may be realized by loading a program installed in the auxiliary storage device into the memory device and executing it on the CPU. The functions of the other components in the control unit 95 (comparator 95E, flow rate difference calculator 95F, comparator 95G, and high selector 95H) may be similar.

[0072] In this example, the differential pressure calculator 95D calculates the differential pressure ΔP (=Pin-P) obtained by subtracting the bearing gas pressure P inside the housing 31 from the bearing gas pressure Pin supplied inside the housing 31. Specifically, the differential pressure calculator 95D calculates the measured value of the differential pressure ΔP by subtracting the measured value of the bearing gas pressure P obtained by the pressure converter 90 from the measured value of the bearing gas pressure Pin obtained by the pressure gauge 92.

[0073] The output of the differential pressure calculator 95D, that is, the calculation result of the differential pressure ΔP, is input to a comparator 95E via a predetermined communication line such as a one-to-one communication line or a local network (LAN).

[0074] The comparator 95E compares the measured value of the differential pressure ΔP input from the differential pressure calculator 95D with a predetermined control standard (for convenience, referred to as the “first control standard”) related to the opening of the supply valve 70, and outputs a manipulated value (MV) representing the opening of the supply valve 70 based on the comparison result. The first control standard is predetermined so that the differential pressure ΔP is equal to or greater than a predetermined lower limit value ΔPmin. The lower limit value ΔPmin is predetermined, for example, through experiments, computer simulations, or the like, as the lower limit value of the differential pressure ΔP necessary to prevent contact between the collar 33 and the housing 31. This allows the comparator 95E to output an appropriate MV value representing the opening of the supply valve 70 in order to prevent contact between the collar 33 and the housing 31.

[0075] For example, as shown in FIG. 4, in the first control standard, the manipulated variable (MV) representing the opening of the supply valve 70 is maintained at a constant value when the differential pressure ΔP is equal to or greater than a threshold ΔPth (>0), and is defined so that the smaller the differential pressure ΔP is, the larger the manipulated variable (MV) becomes when the differential pressure ΔP is smaller than the threshold ΔPth. The threshold ΔPth is defined in advance as a value equal to or greater than a lower limit ΔPmin. In this example, when the differential pressure ΔP is smaller than the threshold ΔPth, the relationship between the differential pressure ΔP and the MV value is expressed by a linear function such that the smaller the differential pressure ΔP is, the larger the MV value becomes. Furthermore, when the differential pressure ΔP is smaller than the threshold ΔPth, the relationship between the differential pressure ΔP and the MV value may be expressed in a form other than a linear function.

[0076] The output of the comparator 95E, ie, the MV value representing the opening degree of the supply valve 70, is taken into the high selector 95H via a predetermined communication line such as a one-to-one communication line or a local network (LAN).

[0077] Based on the outputs of flow meters 93 and 94, the flow rate difference calculator 95F calculates the difference (flow rate difference ΔF) between the flow rate Fin of the bearing gas supplied to the inside of the housing 31 through the supply path 60 and the flow rate Fout of the bearing gas discharged from the inside of the housing 31 through the discharge path 80.

[0078] In this example, the flow rate difference calculator 95F calculates the flow rate difference ΔF (=Fin-Fout) by subtracting the flow rate Fout discharged to the outside of the housing 31 from the flow rate Fin supplied to the inside of the housing 31. Specifically, the flow rate difference calculator 95F calculates the measured value of the flow rate Fout of the bearing gas discharged to the outside of the housing 31, obtained by the flow meter 94, from the measured value of the flow rate Fin of the bearing gas supplied to the inside of the housing 31, obtained by the flow meter 93, to calculate the measured value of the flow rate difference ΔF.

[0079] The output of the flow rate difference calculator 95F, that is, the calculation result of the flow rate difference ΔF, is input to a comparator 95G and a flow rate reverse rotation detector 96B via a predetermined communication line such as a one-to-one communication line or a local network (LAN).

[0080] The comparator 95G compares the measured value of the flow rate difference ΔF input from the flow rate difference calculator 95F with a predetermined control standard (conveniently referred to as the "second control standard") related to the opening of the supply valve 70, and outputs a manipulated variable (MV) representing the opening of the supply valve 70 based on the comparison result. The second control standard is, for example, predetermined so that the flow rate difference ΔF is a desired value (target value ΔFtgt). Alternatively, the second control standard may be predetermined so that the flow rate difference ΔF falls within a desired range (target range) including the target value ΔFtgt. The target range is a range defined by a lower limit value ΔFth1 smaller than the target value ΔFtgt and an upper limit value ΔFth2 larger than the target value ΔFtgt. The target range is, for example, predetermined through experiments or computer simulation as an allowable range of the flow rate difference ΔF centered on the target value ΔFtgt. The target value ΔFtgt is, for example, zero (0). This allows comparator 95G to output an MV value representing the opening of supply valve 70 so that the flow rate Fin of bearing gas supplied into the interior of housing 31 through supply path 60 is the same as the flow rate Fout of bearing gas discharged to the outside of housing 31 through discharge path 80. In other words, comparator 95G can output an MV value representing the opening of supply valve 70 so as to reduce leakage of bearing gas through the through-hole on the impeller 40 side of rotating shaft 20 in housing 31 and the inflow of process gas from the impeller 40 side into the interior of housing 31.

[0081] For example, as shown in FIG. 5, in the second control standard, the manipulated variable (MV) representing the opening of the supply valve 70 is maintained at a constant value when the flow rate difference ΔF is within the target range (i.e., greater than or equal to the lower limit ΔFth1 and less than or equal to the upper limit ΔFth2), is increased as the flow rate difference ΔF decreases when the flow rate difference ΔF is smaller than the lower limit ΔFth1, and is decreased as the flow rate difference ΔF increases when the flow rate difference ΔF is greater than the upper limit ΔFth2. In this example, the relationship between the flow rate difference ΔF and the MV value is expressed by a linear function such that the MV value increases as the flow rate difference ΔF decreases when the flow rate difference ΔF is smaller than the lower limit ΔFth1. Similarly, in this example, the relationship between the flow rate difference ΔF and the MV value is expressed by a linear function such that the MV value decreases as the flow rate difference ΔF increases when the flow rate difference ΔF is greater than the upper limit ΔFth2. Furthermore, when the flow rate difference ΔF is smaller than the lower limit value ΔFth1 or when the flow rate difference ΔF is larger than the upper limit value ΔFth2, the relationship between the flow rate difference ΔF and the MV value may be expressed in a form other than a linear function.

[0082] The output of the comparator 95G, ie, the MV value representing the opening degree of the supply valve 70, is taken into the high selector 95H via a predetermined communication line such as a one-to-one communication line or a local network (LAN).

[0083] The high selector 95H selects the larger of the outputs of both comparators 95E and 95G, i.e., the MV values ​​representing the opening degree of the supply valve 70, and outputs a control command to the supply valve 70 to set the opening degree corresponding to the selected MV value.

[0084] As a result, high selector 95H can control the aperture of supply valve 70 so that flow rate difference ΔF is within the target range under the condition that differential pressure ΔP is equal to or greater than lower limit value ΔPmin. Therefore, high selector 95H can bring flow rate difference ΔF close to the target value or within the target range while preventing contact between collar 33 and housing 31. Therefore, under the condition that contact between collar 33 and housing 31 is prevented, high selector 95H can suppress leakage of bearing gas through the through-hole in housing 31 on the impeller 40 side of rotating shaft 20 and the flow rate of process gas into housing 31.

[0085] The control unit 96 controls the pressure of the process gas flowing into the inlet of the impeller 40 by adjusting the opening of the pressure control valve 46 provided in the inlet path 45. For example, as shown in FIG. 3, the control unit 96 includes a pressure setter 96A, a flow rate reversal detector 96B, a set value adjuster 96C, and a pressure controller 96D.

[0086] The pressure setter 96A sets a target value (pressure set value P1s) of the pressure P1 at the inlet of the impeller 40 based on a target value of the pressure (e.g., the filling pressure of the hydrogen tank TNK) of the process gas to be supplied to the destination (e.g., the hydrogen tank TNK in Figure 6 described below).

[0087] The function of the pressure setter 96A is realized by any hardware or any combination of hardware and software. For example, the function of the pressure setter 96A is realized by, for example, a hardware arithmetic circuit. Alternatively, the pressure setter 96A may be configured mainly with a computer including a CPU, a memory device, an auxiliary storage device, etc., and the function of the pressure setter 96A may be realized by a program installed in the auxiliary storage device being loaded into the memory device and executed by the CPU. The functions of the other components in the control unit 96 (flow rate reversal detector 96B, set value adjuster 96C, and pressure controller 96D) may be similar.

[0088] For example, the target value of the pressure of the process gas supplied to the supply destination is varied from the start to the end of the supply of the process gas in accordance with predetermined conditions (for example, a filling protocol for filling a hydrogen tank TNK with hydrogen gas). In this case, the pressure setter 96A sequentially sets the pressure set value P1s in accordance with the varied target value.

[0089] The output of the pressure setter 96A, i.e., the pressure set value P1s set by the pressure setter 96A, is input to the set value adjuster 96C via a predetermined communication line such as a one-to-one communication line or a local network (LAN).

[0090] Based on the output of comparator 95G, flow rate reversal detector 96B detects a reversal phenomenon in which the flow rate Fout of bearing gas supplied to the outside of housing 31 through discharge path 80 is greater than the flow rate Fin of bearing gas supplied to the inside of housing 31 through supply path 60. The reversal phenomenon occurs when process gas flows into the inside of housing 31 through a through-hole in housing 31 on the impeller 40 side of rotating shaft 20.

[0091] For example, if the measured value of the flow rate difference ΔF input from the comparator 95G is smaller than the threshold value ΔFth3 (≦0), the flow rate reversal detector 96B determines that the above-mentioned reversal phenomenon is occurring and detects the reversal phenomenon. On the other hand, if the measured value of the flow rate difference ΔF is equal to or greater than the threshold value ΔFth3, the flow rate reversal detector 96B determines that the above-mentioned reversal phenomenon is not occurring.

[0092] The output of the flow rate reversal detector 96B (for example, a signal indicating whether or not the above-mentioned reversal phenomenon has been detected) is input to the set value adjuster 96C via a predetermined communication line such as a one-to-one communication line or a local network (LAN).

[0093] The set value adjuster 96C adjusts the pressure set value P1s input from the pressure setter 96A based on the output of the flow rate reverse direction detector 96B. Specifically, when the output of the flow rate reverse direction detector 96B indicates that the above-mentioned reversal phenomenon has been detected, the set value adjuster 96C adjusts the pressure set value P1s and outputs the adjusted pressure set value P1s. On the other hand, in other cases, the set value adjuster 96C does not adjust the pressure set value P1s, and outputs the pressure set value P1s set by the pressure setter 96A as is.

[0094] The output of the set value adjuster 96C, that is, the pressure set value P1s, is input to the pressure controller 96D via a predetermined communication line such as a one-to-one communication line or a local network (LAN).

[0095] The pressure controller 96D controls the opening of the pressure control valve 46 based on the pressure set value P1s input from the set value adjuster 96C so that the pressure P1 of the process gas flowing into the inlet of the impeller 40 becomes the pressure set value P1s.

[0096] For example, the pressure controller 96D sets the opening degree of the pressure control valve 46 based on information representing the relationship between a predetermined pressure set value P1s and the opening degree of the pressure control valve 46, and outputs a control signal corresponding to the set opening degree to the pressure control valve 46.

[0097] Specifically, when the output of the flow rate reversal detector 96B indicates the detection of the reversal phenomenon, the set value adjuster 96C adjusts the pressure set value P1s input from the pressure setter 96A downward. The adjustment amount is predetermined within a margin range that does not affect the target pressure value of the process gas supplied to the destination. The adjustment amount may be fixed or may be variable, for example, so that it increases as the measured value of the flow rate difference ΔF decreases. Thus, the pressure controller 96D controls the pressure control valve 46 based on the adjusted pressure set value P1s, thereby reducing the pressure of the process gas flowing into the inlet of the impeller 40 more than when the pressure control valve 46 is controlled based on the pressure set value P1s set by the pressure setter 46A. Therefore, the pressure controller 96D can suppress the inflow of the process gas into the housing 31 through the through-hole on the impeller 40 side of the rotating shaft 20 in the housing 31.

[0098] [Other examples of control systems] Next, another example of the control system 1 will be described.

[0099] The first to third examples of the control system 1 described above may be modified or changed as appropriate.

[0100] For example, in the first to third examples of the control system 1 described above, the supply valve 70 may be controlled based on information other than the actual measurement value of the bearing gas pressure P inside the housing 31 or the differential pressure ΔP between the bearing gas pressure P inside the housing 31 and the process gas pressure P1 at the inlet of the impeller 40. For example, the control unit 95 controls the opening of the supply valve 70 based on the actual measurement value of the temperature T at the outlet of the impeller 40. This is because the control unit 95 can grasp the state of leakage of bearing gas from inside the housing 31 to the inlet of the impeller 40 based on the difference between the actual measurement value of the temperature T at the outlet of the impeller 40 and the expected temperature, whether or not the temperature T is on the rise, etc.

[0101] [Example of expansion turbine application] Next, with reference to FIG. 6, an application example of the expansion turbine 10 included in the control system 1 according to this embodiment will be described.

[0102] Fig. 6 is a diagram showing an application example of the expansion turbine 10. Specifically, Fig. 6 is a diagram showing an example of a hydrogen gas filling system SYS.

[0103] The hydrogen gas filling system SYS is installed, for example, in a hydrogen station for filling a vehicle VCL with hydrogen gas. In this example, the process gas is hydrogen gas.

[0104] As shown in FIG. 6, the hydrogen gas filling system SYS includes a hydrogen gas compression facility 100, an expansion valve 200, a hydrogen gas line 300, a pre-cooling system 400, and a dispenser 500.

[0105] The hydrogen gas compression equipment 100 compresses hydrogen gas supplied from a tank, boosts the pressure to a predetermined level, and outputs the compressed hydrogen gas.

[0106] The expansion valve 200 adiabatically expands (isenthalpic expands) the hydrogen gas output from the hydrogen gas compression equipment 100. At this time, since the temperature of the hydrogen gas before expansion is higher than the inversion temperature (-58°C), the temperature of the hydrogen gas after expansion rises due to the Joule-Thomson effect.

[0107] The hydrogen gas line 300 supplies the expanded hydrogen gas output from the expansion valve 200 to the pre-cooling system 400 .

[0108] The pre-cooling system 400 cools the hydrogen gas supplied from the hydrogen gas line 300 and supplies it to the dispenser 500 .

[0109] The pre-cooling system 400 includes a compressor 410 , a chiller 420 , a cold source 430 , and an expansion section 440 .

[0110] The compressor 410 compresses the hydrogen gas supplied from the hydrogen gas line 300 .

[0111] The cooler 420 exchanges heat between a refrigerant supplied from a cold heat source 430 and the hydrogen gas compressed by the compressor 410, thereby cooling the hydrogen gas.

[0112] The cold heat source 430 supplies a refrigerant having a temperature lower than that of the hydrogen gas output from the compressor 410 to the cooler 420 and circulates it.

[0113] A cooler similar to the cooler 420 may be provided upstream of the compressor 410, and the hydrogen gas in the hydrogen gas line 300 may be introduced into the compressor 410 after being cooled by the cooler.

[0114] The expansion section 440 expands the hydrogen gas cooled by the cooler 420. This allows the hydrogen gas to expand and lower its temperature. Furthermore, by expanding the hydrogen gas compressed by the compressor 410, the expansion ratio becomes relatively large, and as a result, the temperature of the hydrogen gas can be lowered more significantly. Therefore, the temperature of the hydrogen gas can be lowered to an appropriate level without requiring a pre-cooling system that requires a refrigerator equipment including, for example, a compressor, a condenser, an expansion valve, an evaporator, an accumulator, and the like.

[0115] In this example, the compressor 410 and the expansion section 440 are realized by the expansion turbine 10. Specifically, the expansion turbine 10 realizes the function of the expansion section 440 by expanding hydrogen gas with the impeller 40 at one end of the rotary shaft 20, and realizes the function of the compressor 410 by compressing hydrogen gas with the impeller 50 at the other end of the rotary shaft 20.

[0116] In this example, a supply path 60 branches off from the hydrogen gas line 300. This allows the hydrogen gas filling system SYS to supply process gas as bearing gas to the inside of the housing 31 of the bearing device 30 incorporated in the expansion turbine 10 through the supply path 60 and supply paths 61 and 62 branching off from the supply path 60.

[0117] The discharge path 80 is connected, for example, to the front stage of the compression process of the hydrogen gas compression equipment 100. This allows the bearing gas (process gas) discharged from the housing 31 of the bearing device 30 to be reused.

[0118] The dispenser 500 fills the hydrogen tank TNK of the vehicle VCL with high-pressure hydrogen gas supplied from the pre-cooling system 400. The vehicle VCL is, for example, a fuel cell vehicle equipped with a fuel cell capable of generating electricity using hydrogen gas as fuel.

[0119] In this way, the expansion turbine 10 can be applied to the pre-cooling system 400 of the hydrogen gas filling system SYS.

[0120] [Effect] Next, the operation of the control system and control method according to this embodiment will be described.

[0121] In a first aspect of this embodiment, the control system includes a bearing device, a supply path, a discharge path, a flow rate adjustment unit, and a first control unit. The control system is, for example, the control system 1 described above. The bearing device is, for example, the bearing device 30 described above. The supply path is, for example, the supply paths 60 to 62 described above. The discharge path is, for example, the discharge path 80 described above. The flow rate adjustment unit is, for example, the supply valve 70 described above. The first control unit is, for example, the control unit 95 described above. Specifically, the bearing device includes a housing and a support unit that supports a rotating shaft using lubricating gas supplied to the inside of the housing. The housing is, for example, the housing 31 described above. The support unit is, for example, the thrust bearing 34 described above. The supply path supplies the lubricating gas to the inside of the housing. The discharge path discharges the lubricating gas to the outside of the housing. The flow rate adjustment unit is provided in the supply path and adjusts the flow rate of the lubricating gas supplied to the inside of the housing. The first control unit controls the flow rate of the lubricating gas supplied to the inside of the housing using the flow rate adjustment unit based on information about the outflow state of the lubricating gas from a path different from the exhaust path to the outside of the housing. The information about the outflow state of the lubricating gas from a path different from the exhaust path to the outside of the housing includes, for example, information about the actual measured value of the bearing gas pressure P inside the housing 31 based on the detection signal of the pressure transducer 90 described above. The information about the outflow state of the lubricating gas from a path different from the exhaust path to the outside of the housing includes, for example, information about the actual measured value of the process gas pressure P1 at the inlet of the impeller 40 based on the detection signal of the pressure transducer 91 described above. The information about the outflow state of the lubricating gas from a path different from the exhaust path to the outside of the housing includes, for example, a measured value of the flow rate Fin of the bearing gas supplied to the inside of the housing 31 through the supply path 60 obtained by the flow meter 93 described above, and a measured value of the flow rate Fout of the bearing gas exhausted to the outside of the housing 31 through the exhaust path 80 obtained by the flow meter 94 described above. Furthermore, the information regarding the outflow state of the lubricating gas to the outside of the housing through a path different from the exhaust path includes, for example, information regarding the actual measured value of the temperature at the outlet of the impeller 40 described above.

[0122] In addition, in a first aspect of this embodiment, a control method executed by a control system relates to a bearing device including a housing and a support part that supports a rotating shaft using lubricating gas supplied to the inside of the housing, a supply path that supplies the lubricating gas to the inside of the housing, a discharge path that discharges the lubricating gas to the outside of the housing, and a flow rate adjustment unit that is provided in the supply path and adjusts the flow rate of the lubricating gas supplied to the inside of the housing. Specifically, the control method according to this aspect uses the flow rate adjustment unit to control the flow rate of the lubricating gas supplied to the inside of the housing based on information about an outflow state of the lubricating gas to the outside of the housing from a path different from the discharge path.

[0123] This allows the control system to control the flow rate of the lubricating gas so as to prevent the lubricating gas from leaking out of the housing through a route other than the regular exhaust route. Therefore, the control system can prevent the lubricating gas from leaking out of the housing through a route other than the regular exhaust route.

[0124] In a second aspect of this embodiment, based on the first aspect described above, the information relating to the outflow state of the lubricating gas from a path different from the exhaust path to the outside of the housing may include information representing the inflow state of the lubricating gas into the interior of the housing through the supply path, and information representing the outflow state of the lubricating gas to the outside of the housing through the exhaust path. The information representing the inflow state of the lubricating gas into the interior of the housing through the supply path is, for example, a measured value of the flow rate Fin of the bearing gas supplied to the housing 31 through the supply path 60, obtained by the above-mentioned flow meter 93. The information representing the outflow state of the lubricating gas to the outside of the housing through the exhaust path is, for example, a measured value of the flow rate Fout of the bearing gas exhausted from the housing 31 through the exhaust path 80, obtained by the above-mentioned flow meter 94.

[0125] This allows the control system to grasp the outflow state of lubricating gas to the outside of the housing through a path different from the regular exhaust path based on the inflow state of lubricating gas into the housing through the supply path and the outflow state of lubricating gas into the housing through the regular exhaust path. Therefore, the control system can control the flow rate of lubricating gas so as to suppress the outflow of lubricating gas to the outside of the housing through a path different from the regular exhaust path. Therefore, the control system can suppress the outflow of lubricating gas to the outside of the housing through a path other than the regular exhaust path.

[0126] In a third aspect of this embodiment, based on the second aspect, the control system may include an impeller, a pressure adjusting unit, and a second control unit. The impeller may be, for example, the impeller 40 described above. The pressure adjusting unit may be, for example, the pressure control valve 46 described above. The second control unit may be, for example, the control unit 96 described above. Specifically, the impeller may be attached to one end of the rotating shaft that passes through a through-hole provided in the housing and is exposed to the outside of the housing, and may expand the same type of gas as the lubricating gas. The pressure adjusting unit may adjust the pressure of the gas flowing into the impeller. The second control unit may use the pressure adjusting unit to control the pressure of the gas flowing into the impeller based on information indicating the inflow state of the lubricating gas into the housing through the supply path and information indicating the outflow state of the lubricating gas to the outside of the housing through the discharge path.

[0127] This allows the control system to grasp the outflow status of lubricating gas from the interior of the housing to the impeller inlet and the inflow status of lubricating gas from the impeller inlet to the interior of the housing based on the inflow status of lubricating gas into the interior of the housing through the supply path and the outflow status of lubricating gas into the interior of the housing through the regular exhaust path. Therefore, the control system can control the pressure of the fluid flowing into the impeller inlet using a pressure control valve to suppress the outflow of lubricating gas from the interior of the housing to the impeller inlet and the inflow of gas from the impeller inlet to the interior of the housing. Thus, the control system can, for example, suppress the outflow of lubricating gas from the interior of the housing to the impeller inlet and suppress an increase in the temperature of the gas at the impeller outlet due to a shortcut of the lubricating gas from the impeller inlet to the impeller outlet. Furthermore, the control system can, for example, suppress the inflow of gas from the impeller inlet into the interior of the housing and suppress a decrease in the flow rate of gas discharged from the impeller outlet.

[0128] In addition, in a fourth aspect of this embodiment, assuming the first aspect described above, the information regarding the outflow state of the lubricating gas to the outside of the housing from a path different from the exhaust path may include information representing the pressure of the lubricating gas inside the housing.

[0129] As a result, the control system can use, for example, the flow rate adjusting unit to perform feedback control on the pressure of the lubricating gas inside the housing so that the pressure of the lubricating gas inside the housing does not become excessively high relative to the pressure of the gas to which the lubricating gas is discharged. Therefore, the control system can appropriately suppress the discharge of the lubricating gas from a path different from the normal discharge path. In a fifth aspect of this embodiment, based on the fourth aspect described above, the information regarding the outflow state of the lubricating gas from the path different from the discharge path to the outside of the housing may include information indicating the pressure of the gas at the destination of the lubricating gas via the path different from the discharge path. The destination of the lubricating gas via the path different from the discharge path may be, for example, the inlet of the impeller 40 described above. The first control unit may use the flow rate adjustment unit to control the flow rate of the lubricating gas supplied to the inside of the housing based on the pressure difference between the pressure of the gas at the destination and the pressure of the lubricating gas inside the housing.

[0130] As a result, the control system can use, for example, the flow rate adjusting unit to perform feedback control of the pressure difference between the pressure of the lubricating gas inside the housing and the pressure of the gas to which the lubricating gas is discharged so that the pressure difference does not become excessive. As a result, the control system can more appropriately suppress the discharge of the lubricating gas from a path different from the normal discharge path. In a sixth aspect of this embodiment, based on the fifth aspect described above, the control system may further include an impeller attached to one end of the rotating shaft that passes through a through-hole provided in the housing and is exposed to the outside of the housing, and that expands the same type of gas as the lubricating gas. The impeller is, for example, the impeller 40 described above. The information representing the pressure of the gas at the outflow destination may be information representing the pressure of the gas at the inlet of the impeller, through which the lubricating gas can flow out through the through-hole. The information representing the pressure of the gas at the impeller inlet is, for example, information representing the actual measured value of the pressure P1 at the inlet of the impeller 40 corresponding to the detection signal of the pressure transducer 91.

[0131] This allows the control system to suppress outflow of lubricating gas from inside the housing to the inlet of the impeller, thereby suppressing an increase in the temperature of the gas at the outlet of the impeller due to a shortcut of the lubricating gas from the inlet of the impeller to the outlet of the impeller.

[0132] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0133] 1. Control System 10 Expansion turbine 20 Rotation axis 30 Bearing device 31 Case 33 Color 34 Thrust bearing 34A injection hole 40 impeller 45 Inflow route 46 Pressure control valve 60~62 Supply Channel 70 Supply valve 80 Emission Route 90,91 Pressure transducer 92 Pressure gauge 93 Flow meter 94 Flow meter 95 Control Unit 95A~95C Control unit 95D Differential Pressure Calculator 95E Comparator 95F Flow rate difference calculator 95G comparator 95H High Selector 96 Control Unit 96A Pressure Setting Device 96B Flow Reverse Detector 96C Setpoint Adjuster 96D Pressure Controller

Claims

1. a bearing device including a housing and a support part that supports a rotating shaft using a lubricating gas supplied to the inside of the housing; a supply path for supplying the lubricating gas into the housing; an exhaust path for exhausting the lubricating gas to the outside of the housing; a flow rate adjusting unit that is provided in the supply path and adjusts the flow rate of the lubricating gas supplied to the inside of the housing; a first control unit that controls the flow rate of the lubricating gas supplied to the inside of the housing using the flow rate adjustment unit based on information regarding an outflow state of the lubricating gas to the outside of the housing through a path different from the exhaust path, Control system.

2. The information regarding the outflow state of the lubricating gas from a path different from the exhaust path to the outside of the housing includes information indicating the inflow state of the lubricating gas into the inside of the housing through the supply path, and information indicating the outflow state of the lubricating gas to the outside of the housing through the exhaust path. The control system of claim 1 .

3. an impeller attached to one end of the rotating shaft that passes through a through hole provided in the housing and is exposed to the outside of the housing, and that expands the same type of gas as the lubricating gas; a pressure adjusting unit that adjusts the pressure of the gas flowing into the impeller; a second control unit that controls the pressure of the gas flowing into the impeller using the pressure adjusting unit based on information representing an inflow state of the lubricating gas into the housing through the supply path and information representing an outflow state of the lubricating gas to the outside of the housing through the discharge path. The control system of claim 2 .

4. the information relating to the outflow state of the lubricating gas to the outside of the housing through a path different from the exhaust path includes information representing the pressure of the lubricating gas inside the housing; The control system of claim 1 .

5. the information relating to the outflow state of the lubricating gas from the path different from the exhaust path to the outside of the housing includes information representing a pressure of the gas at the destination of the lubricating gas in the path different from the exhaust path; the first control unit controls the flow rate of the lubricating gas supplied to the inside of the housing using the flow rate adjustment unit based on a pressure difference between the pressure of the gas at the outflow destination and the pressure of the lubricating gas inside the housing. The control system of claim 4.

6. an impeller attached to one end of the rotating shaft that passes through a through hole provided in the housing and is exposed to the outside of the housing, the impeller expanding the same type of gas as the lubricating gas; the information representing the pressure of the gas at the outflow destination is information representing the pressure of the gas at the inlet of the impeller, through which the lubricating gas can flow out through the through hole; The control system of claim 5 .

7. A control method for a bearing device including a housing and a support part that supports a rotating shaft using lubricating gas supplied to the inside of the housing, a supply path that supplies the lubricating gas to the inside of the housing, a discharge path that discharges the lubricating gas to the outside of the housing, and a flow rate adjustment part that is provided in the supply path and adjusts the flow rate of the lubricating gas supplied to the inside of the housing, using the flow rate adjusting unit to control the flow rate of the lubricating gas supplied into the housing based on information about an outflow state of the lubricating gas to the outside of the housing through a path different from the exhaust path. Control method.

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