Refrigeration apparatus, lithography apparatus, article manufacturing method, and control device and control method for refrigeration apparatus

Abstract

To provide a technique advantageous for early detecting a sign of an abnormality in a refrigerating device.SOLUTION: A refrigerating device comprises: a refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator; a detector for detecting the state of a refrigerant in the refrigerant circuit; an acquisition unit for acquiring the drive current value of the compressor; and a control unit for determining the state of the compressor. When the output of the detector is normal, and the drive current value acquired by the acquisition unit indicates an abnormality, the control unit determines that the compressor has the abnormality.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a refrigeration apparatus, a lithography apparatus, an article manufacturing method, and a control device and control method for a refrigeration apparatus. [Background technology]

[0002] In a refrigeration system that cools an object by circulating a refrigerant through a refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator, deterioration over time can cause the refrigerant to leak along with the compressor's lubricating oil, leading to a shortage of lubricating oil for the compressor.When the compressor's lubricating oil runs out, the compressor's bearings seize, the shaft locks, and the compressor becomes unable to operate.

[0003] When a refrigeration system is used to recover heat generated by a lithography system such as an exposure system, a compressor shutdown can result in a malfunction of the cooling system, which can increase the likelihood of defective products being produced. Therefore, when the compressor shuts down, the operation of the lithography system must be temporarily stopped and the compressor must be replaced with a working one or its lubricant must be replenished. Until the lithography system is restored, production of products cannot be continued. Therefore, it is desirable to detect early signs of compressor shaft lock and replace the compressor with a working one or replenish its lubricant during maintenance, etc.

[0004] Patent Document 1 describes diagnosing an abnormality in a refrigeration system using two state quantities A and B. State quantity A is the refrigerant pressure or temperature, or the drive current value of the compressor, etc., which are necessary to understand the operating state of the refrigeration cycle. State quantity B is the sound or vibration around the compressor, which is necessary to understand the operating state of the compressor. State quantities A and B are combined to calculate a composite variable, i.e., Mahalanobis distance, and a comprehensive abnormality diagnosis of the refrigeration system is performed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-241089 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the method described in Patent Document 1, noise is added to the vibration and sound data, which are state quantity B, due to vibrations and sounds in the environment in which the refrigeration device is installed, so there is a possibility that an abnormality in the refrigeration device cannot be accurately diagnosed.

[0007] An object of the present invention is to provide an advantageous technique for early detection of signs of abnormality in a refrigeration device. [Means for solving the problem]

[0008] One aspect of the present invention relates to a refrigeration apparatus, the refrigeration apparatus including: a refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator; a detector for detecting a state of a refrigerant in the refrigerant circuit; an acquisition unit for acquiring a drive current value of the compressor; and a control unit for determining a state of the compressor. an inverter that drives the compressor; and the control unit is configured to determine whether the output of the detector is normal and whether the drive current value acquired by the acquisition unit is Exceeded the judgment threshold In this case, the compressor bearings is determined to have an abnormality death , After changing the output frequency of the inverter, the drive current value is waited for to stabilize, and the determination threshold is set according to the drive current value after stabilization. . [Effects of the Invention]

[0009] According to the present invention, an advantageous technique for early detection of signs of abnormality in a refrigeration device is provided. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing the configuration of a refrigeration device according to an embodiment; [Figure 2] FIG. 1 is a diagram showing a schematic structure of a scroll compressor. [Figure 3] 4A is a diagram illustrating the refrigerant pressure and the drive current value of the compressor in a normal state; FIG. [Figure 4]4A and 4B are diagrams illustrating an example of a refrigerant pressure and a compressor drive current value during an initial abnormality. [Figure 5] 4A and 4B are diagrams illustrating an example of the refrigerant pressure and the drive current value of the compressor during a failure. [Figure 6] FIG. 10 is a diagram illustrating an example of a change in drive current value during a period from when bearing galling begins to occur until the compressor shaft locks. [Figure 7] FIG. 4 is a diagram illustrating an example of a monitoring operation of the refrigeration device by the control unit. [Figure 8] FIG. 4 is a diagram illustrating an example of a change in a drive current value of a compressor when an operation frequency is changed. [Figure 9] FIG. 4 is a diagram illustrating a transition of a drive current value from an initial abnormality in a compressor to the compressor becoming unusable (failure); [Figure 10] FIG. 1 is a diagram illustrating the configuration of an exposure apparatus according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0012] FIG. 1 illustrates an example of the configuration of a refrigeration apparatus 10 according to one embodiment. The refrigeration apparatus 10 may include a refrigerant circuit 20. The refrigerant circuit 20 may include a compressor 11, a condenser 12, an expansion valve 13, and an evaporator 14. The refrigerant circulating within the refrigerant circuit 20 is supplied in a gaseous state to the compressor 11, compressed in the compressor 11, and then supplied to the condenser 12. A low-temperature fluid (e.g., water or air) is supplied to the condenser 12, and the high-temperature gaseous refrigerant compressed by the compressor 11 is cooled by heat exchange with the low-temperature fluid, thereby condensing and changing from a gaseous state to a liquid state. A flow control valve 15 may be provided to control the flow rate of the low-temperature fluid supplied to the condenser 12. The refrigerant condensed in the condenser 12 is expanded by the expansion valve 13 and then evaporates into a gas by exchanging heat with an object to be cooled in the evaporator 14, and then returns to the compressor 11. The object to be cooled (e.g., air) cooled by the evaporator 14 is heated by, for example, a heater 30 and then supplied to a cooling object (e.g., a structure or space). A temperature sensor 31 for measuring the temperature of the object to be cooled that is supplied to the cooling object is provided immediately before the cooling object, and the heater 30 can be controlled so that the temperature measured by the temperature sensor 31 becomes a target temperature. The refrigeration device 10 can include an inverter 25 (drive circuit) that drives the compressor 11.

[0013] The refrigeration device 10 may include at least one of a high-pressure acquisition unit 21 and a low-pressure acquisition unit 22 as detectors for detecting the state of the refrigerant in the refrigerant circuit 20. The high-pressure acquisition unit 21 may include a pressure sensor that measures the pressure (high pressure) of the refrigerant passing through a high-pressure section (a section where the refrigerant pressure is high) of the refrigerant circuit 20 (for example, between the condenser 12 and the expansion valve 13). The low-pressure acquisition unit 22 may include a pressure sensor that measures the pressure (low pressure) of a low-pressure section (a section where the refrigerant pressure is low) of the refrigerant circuit 20 (for example, between the evaporator 14 and the compressor 11). Instead of the high-pressure acquisition unit 21, a high-temperature acquisition unit 32 that measures the temperature of the refrigerant passing through the high-pressure section (high-temperature section) of the refrigerant circuit 20 may be provided. Alternatively, instead of the low-pressure acquisition unit 22, a low-temperature acquisition unit 33 that measures the temperature of the refrigerant passing through the low-pressure section (low-temperature section) of the refrigerant circuit 20 may be provided. Generally, it is more convenient to detect pressure than temperature as a detector for detecting the state of the refrigerant in the refrigerant circuit 20. Therefore, in this embodiment, a configuration in which the high pressure acquisition unit 21 and the low pressure acquisition unit 22 are provided as detectors that detect the state of the refrigerant in the refrigerant circuit 20 will be described.

[0014] The refrigeration apparatus 10 may include a control unit 24. The control unit 24 may be configured, for example, by a PLD (abbreviation for programmable logic device) such as an FPGA (abbreviation for field programmable gate array), an ASIC (abbreviation for application specific integrated circuit), a general-purpose or dedicated computer with an embedded program, or a combination of all or part of these. The control unit 24 may be configured, for example, to control the aperture of the expansion valve 13 and the flow control valve 15 based on the refrigerant pressure acquired by the high pressure acquisition unit 21 and the low pressure acquisition unit 22, which serve as detectors for detecting the state of the refrigerant in the refrigerant circuit 20. For example, the high pressure acquisition unit 21 acquires (detects) the pressure of the refrigerant after passing through the condenser 12, and the control unit 24 may adjust the aperture of the flow control valve 15 based on the pressure acquired by the high pressure acquisition unit 21 so that the pressure acquired by the high pressure acquisition unit 21 matches a first target pressure. In addition, the pressure of the refrigerant after passing through the evaporator 14 is acquired (detected) by the low pressure acquisition unit 22, and the control unit 24 can adjust the opening degree of the expansion valve 13 based on that pressure so that the pressure acquired by the low pressure acquisition unit 22 matches the second target pressure.

[0015] The refrigeration device 10 may include a current acquisition unit 23. The compressor 11 has a shaft, and the rotation speed of the shaft may be controlled to a target speed by an inverter 25 (drive circuit) controlled by the control unit 24. The current acquisition unit 23 may be configured to acquire (measure) the value of the current supplied from the inverter 25 to the compressor 11 when the shaft of the compressor 11 rotates, i.e., the drive current value. The control unit 24 may monitor or control the state of the refrigeration device 10 based on information output or provided from the high pressure acquisition unit 21, the low pressure acquisition unit 22, and the current acquisition unit 23.

[0016] The compressor 11 may be a positive displacement compressor, a centrifugal compressor, or another type. Positive displacement compressors can be broadly divided into three types: reciprocating compressors, which repeatedly compress air by the reciprocating motion of a piston; screw compressors, which perform continuous compression between two screws; and scroll compressors, which excel in low vibration and noise. On the other hand, centrifugal compressors include turbo compressors, which perform compression by centrifugal force using the rotation of an impeller-like impeller.

[0017] FIG. 2 shows the structure of a positive displacement scroll compressor as an example that can be used as compressor 11. The scroll compressor includes a fixed scroll 46 fixed to a housing 42 and an orbiting scroll 47 that orbits relative to the fixed scroll 46. The scroll compressor also includes a shaft 44 connected to the orbiting scroll 47 and an electric motor 45 that rotates the shaft 44. When a driving current is supplied to compressor 11, the electric motor 45 rotates the shaft 44, thereby rotating the orbiting scroll 47. The scroll compressor includes two bearings 43 that support both ends of the shaft 44. Refrigerant flowing in through refrigerant suction port 40 enters between the fixed scroll 46 and the orbiting scroll 47, is compressed as the orbiting scroll 47 orbits, and is discharged from refrigerant discharge port 41.

[0018] Lubricating oil is supplied to the bearing 43 to ensure smooth rotation of the shaft 44. After the refrigerant is compressed by the compressor 11, the lubricating oil circulates within the refrigerant circuit 20 along with the refrigerant. The refrigerant may leak outside the refrigerant circuit 20 due to aging or external factors. In this case, the lubricating oil may also leak along with the refrigerant. If the lubricating oil circulating within the refrigerant circuit 20 becomes insufficient due to leakage, relatively shallow scratches may appear on the raceway and rolling surfaces of the bearing 43 of the compressor 11. At this stage, there is no welding within the scratches. If this condition continues, the bearing 43 will heat up, and the raceway and rolling surfaces will begin to weld locally, leading to a condition known as seizing. A seized bearing 43 will exhibit a sticking behavior during rotation, but will still be able to rotate. If the seizing becomes severe, the welded bearing 43 will become unable to rotate, resulting in a condition known as seizure. Once a bearing 43 seizes, it cannot be reused. Therefore, the refrigeration device 10 cannot be restored unless the compressor 11 is replaced with a new one.

[0019] When the refrigeration apparatus 10 is incorporated into production equipment such as a lithography apparatus, a stop in the operation of the compressor 11 can result in defects in the manufactured goods, so it is necessary for the user to quickly identify and repair any shaft rotation problems in the compressor 11. In this embodiment, the control unit 24 can determine that the compressor 11 has an abnormality (initial abnormality) based on a change in the drive current value of the compressor 11 acquired by the current acquisition unit 23. The abnormality of the compressor 11 can be, for example, an abnormality (e.g., galling) in the bearings 43 of the compressor 11. Here, the control unit 24 can be configured to determine that the compressor 11 has an abnormality when the outputs of the high pressure acquisition unit 21 and the low pressure acquisition unit 22 as detectors are within normal ranges and the drive current value acquired by the current acquisition unit 23 indicates an abnormality.

[0020] In this embodiment, when the control unit 24 determines that an abnormality has occurred in the compressor 11 (e.g., galling of the bearing 43), the control unit 24 may issue an alarm using the alarm unit 34. The alarm may include at least one of an audible alarm, an optical alarm, and an image alarm. The alarm may include information on the type or nature of the estimated abnormality in the compressor 11. The alarm unit 34 may be connected to the control unit 24 via a communication path such as the Internet and / or a LAN. The control unit 24 may be configured as a control device connected to the refrigeration apparatus 10 via a communication path such as the Internet and / or a LAN. In this case, a user of the control unit 24 can monitor or understand the status of the refrigeration apparatus 10 from a location remote from the refrigeration apparatus 10. Alternatively, a control device including all or part of the functions of the control unit 24 may be connected to the refrigeration apparatus 10 including the control unit 24 via a communication path. The concept of a communication path includes any means capable of transmitting data.

[0021] FIG. 3(a) illustrates the high-pressure refrigerant pressure acquired by the high-pressure acquisition unit 21 and the low-pressure refrigerant pressure acquired by the low-pressure acquisition unit 22 when the compressor 11 is in a normal state. In FIG. 3(a), the horizontal axis represents elapsed time, and the vertical axis represents refrigerant pressure. FIG. 3(b) illustrates the drive current value acquired by the current acquisition unit 23 when the compressor 11 is in a normal state. In FIG. 3(b), the horizontal axis represents elapsed time, and the vertical axis represents the drive current value. Under normal conditions, the refrigerant pressures on the high-pressure and low-pressure sides are controlled to target values ​​by adjusting the valve openings of the expansion valve 13 and the flow control valve 15. As long as the frequency of the inverter 25 is constant, the rotation speed of the shaft of the compressor 11 is also controlled to a constant value, so the drive current value remains stable within a predetermined range.

[0022] FIG. 4(a) shows a representative example of the high-pressure refrigerant pressure acquired by the high-pressure acquisition unit 21 or the low-pressure refrigerant pressure acquired by the low-pressure acquisition unit 22 when galling of the bearing 43, an initial abnormality, occurs in the compressor 11. FIG. 4(b) shows an example of the drive current value acquired by the current acquisition unit 23 when galling of the bearing 43, an initial abnormality, occurs in the compressor 11. Even when galling of the bearing 43, an initial abnormality, occurs in the compressor 11, the refrigerant pressure is the same as when the compressor 11 is normal. However, when galling of the bearing 43 occurs, the torque required to rotate the shaft is greater than in a normal state, and the drive current value may temporarily deviate from normal and assume a large value. Although the shaft itself is unable to rotate smoothly, this is a short-term phenomenon and does not affect the refrigerant pressure value. If the shaft is unable to rotate for a long period of time, such as several seconds, this affects the refrigerant pressure value. However, the valve apertures of expansion valve 13 and flow control valve 15 are adjusted to maintain the refrigerant pressure at a predetermined value. Specifically, if compressor 11 is insufficiently compressing the refrigerant for a long period of time, the pressure acquired by high-pressure acquisition unit 21 decreases. This causes flow control valve 15 to be lowered, suppressing the decrease in refrigerant pressure. When the pressure acquired by high-pressure acquisition unit 21 decreases, the refrigerant pressure differential across expansion valve 13 decreases, reducing the refrigerant flow rate and the pressure acquired by low-pressure acquisition unit 22. In response, the valve aperture of expansion valve 13 is increased to suppress the decrease in refrigerant flow rate, thereby increasing the cooling capacity and maintaining the refrigerant pressure at a predetermined, stable value. The shaft rotation failure due to galling is resolved within a few seconds at most, and the drive current continues to decrease until it returns to its normal value. During this time, the pressure of the refrigerant is controlled to a predetermined value by adjusting the valve opening of the expansion valve 13 and the flow rate control valve 15 .

[0023] FIG. 5(a) shows a representative example of the high-pressure refrigerant pressure acquired by the high-pressure acquisition unit 21 or the low-pressure refrigerant pressure acquired by the low-pressure acquisition unit 22 when the shaft of the compressor 11 is locked and unable to rotate. FIG. 5(b) shows an example of the drive current value acquired by the current acquisition unit 23 when the shaft of the compressor 11 is locked and unable to rotate. Unlike the initial abnormality, when the shaft of the compressor 11 is locked and unable to rotate, the drive current value continues to increase. Furthermore, the refrigerant pressure cannot be fully controlled by adjusting the valve openings of the expansion valve 13 and the flow control valve 15, and fluctuates from normal pressure. If an upper limit is set for the drive current value in preparation for an abnormality, the refrigeration system 10 may be stopped when the drive current value reaches the upper limit. When the refrigeration system 10 is stopped, the refrigerant is neither compressed nor expanded, and the refrigerant pressure remains constant, regardless of the location in the refrigerant circuit 20, and remains constant, different from when the refrigeration system 10 is operating.

[0024] The control unit 24 stores normal refrigerant pressure and drive current values ​​in advance, and determines that an initial abnormality has occurred in the compressor 11 when the refrigerant pressure and drive current values ​​become those shown in Fig. 4 for the first time. That is, when the refrigerant pressure remains unchanged from normal and can be controlled to a predetermined value, and the drive current value is a large value that deviates from normal, the control unit 24 determines that an initial abnormality has occurred in the compressor 11.

[0025] FIG. 6 illustrates the transition of the drive current value acquired by the current acquisition unit 23 from the time when galling of the bearing 43 begins to occur until the shaft of the compressor 11 locks. As illustrated in FIG. 6, after multiple temporary increases in the drive current value of the compressor 11, the drive current value may reach an upper limit, causing the refrigeration system 10 to shut down. The temporary increase in the drive current value before the shaft locks may initially occur, for example, once every few months. As the galling becomes more severe, the frequency increases to once every few weeks, then once every few days, before the shaft locks. Therefore, when it is first determined that an initial abnormality has occurred in the compressor 11, it is recommended that the compressor 11 be replaced during scheduled maintenance while the lubricating oil is replenished to extend its life. This prevents the production equipment from shutting down due to sudden seizure of the compressor 11.

[0026] 7 illustrates an example of the monitoring operation of the refrigeration apparatus 10 by the control unit 24. In step 201, the control unit 24 acquires the drive current value of the compressor 11 when the compressor 11 is in a normal state based on the output from the current acquisition unit 23. For example, after starting operation of the refrigeration apparatus 10, the control unit 24 acquires the output of the current acquisition unit 23 in a state in which the pressures of the refrigerant on the high-pressure side and the low-pressure side of the refrigerant circuit 20 acquired by the high-pressure acquisition unit 21 and the low-pressure acquisition unit 22 are both controlled to predetermined values. Then, the control unit 24 can acquire the drive current value of the compressor 11 when the compressor 11 is in a normal state, for example, an average value of the drive current value when the drive current value falls within a predetermined range for a predetermined time.

[0027] In step 202, the control unit 24 acquires the outputs of the high pressure acquisition unit 21 and the low pressure acquisition unit 22, which serve as detectors for detecting the state of the refrigerant in the refrigerant circuit, i.e., the pressures of the refrigerant on the high pressure side and the low pressure side of the refrigerant circuit 20. Here, the control unit 24 acquires the outputs of both the high pressure acquisition unit 21 and the low pressure acquisition unit 22, but the control unit 24 may acquire only one of them. The control unit 24 also acquires the output of the current acquisition unit 23, i.e., the drive current value of the compressor 11 acquired by the current acquisition unit 23.

[0028] In step S203, the control unit 24 determines whether the drive current value acquired by the current acquisition unit 23 in step S202, i.e., the latest drive current value, indicates an abnormality. This determination can be made based on whether the latest drive current value exceeds a determination threshold obtained by adding a margin to the drive current value of the compressor 11 in a normal state acquired in step S201. If the latest drive current value exceeds the determination threshold, the control unit 24 can determine that the latest drive current value indicates an abnormality. If it is determined that the latest drive current value indicates an abnormality, the control unit 24 executes step S204; otherwise, the control unit 24 repeats the processes of steps S202 and S203. The determination threshold or margin can be determined so as to determine whether the bearing is galling. The determination threshold or margin can be determined so as to determine whether the bearing is galling, even though the shaft supported by the bearing is rotatable.

[0029] In step S204, the control unit 24 determines whether the outputs of the detectors that detect the state of the refrigerant in the refrigerant circuit, for example, the outputs of the high pressure acquisition unit 21 and the low pressure acquisition unit 22, are normal. For example, the control unit 24 can determine that the detector outputs are normal if the output of the high pressure acquisition unit 21 is within a first normal range and the output of the low pressure acquisition unit 22 is within a second normal range. If the control unit 24 determines that the detector outputs are normal, the control unit 24 executes step S205; otherwise, the control unit 24 executes step S207.

[0030] In step S205, the control unit 24 determines that the compressor 11 has an abnormality. However, because the refrigerant pressure is still normal, the abnormality in the compressor 11 at this stage is a minor abnormality, i.e., an initial abnormality, which is different from a severe abnormality that requires the refrigeration apparatus 10 to be immediately shut down. In step S205, the control unit 24 may determine the frequency at which the drive current value indicates an abnormality when the detector output is normal. For example, the control unit 24 can determine the frequency at which the drive current value indicates an abnormality when the detector output is normal, based on the frequency at which step S205 is executed. Alternatively, in step S205, the control unit 24 may evaluate the degree of the abnormality in the compressor 11. For example, the control unit 24 can evaluate the degree of the abnormality in the compressor 11 based on the drive current value (magnitude). For example, the control unit 24 can evaluate the degree of the abnormality in the compressor 11 based on the drive current value when step S205 was executed in the past and the latest drive current value.

[0031] Following step S205, in step S206, the control unit 24 uses the notification unit 34 to notify that the compressor 11 has an abnormality (initial abnormality). This notification may include providing information according to the frequency and / or the severity of the abnormality. In response to this notification, the user can promptly take action, such as requesting a service engineer to investigate or repair the abnormality. After step S206 is completed, the processing from step S202 onwards may be repeated.

[0032] Step S207 is executed when the drive current indicates an abnormality and the state of the refrigerant (pressure in this example) also indicates an abnormality, which suggests that a serious abnormality exists in the refrigeration device 10. Therefore, in step S207, the control unit 24 issues an alert using the alert unit 34 to notify that a serious abnormality may exist. The manner of alert in step S207 is different from the manner of alert in step S206.

[0033] As described above, by detecting an abnormality in the compressor 11 based on the drive current of the compressor 11, signs of an abnormality in the refrigeration device 10 can be detected early without being affected by the environment in which the refrigeration device 10 is installed.

[0034] In order to reduce the power consumption of the refrigeration device 10, the control unit 24 may change the output frequency (operating frequency) of the inverter 25 depending on the amount of heat exchanged with the object to be cooled in the evaporator 14. For example, when the amount of heat generated by the object to be cooled increases and the required amount of cooling increases, the control unit 24 may be configured to increase the output frequency of the inverter 25 to increase the rotation rate of the shaft in the compressor 11. When the rotation rate of the shaft increases, as illustrated in FIG. 8, the drive current value of the compressor 11 (the value of the drive current supplied from the inverter 25 to the compressor 11) stabilizes at a value higher than that before the change in frequency. Conversely, when the required amount of cooling of the object to be cooled decreases, the drive current value of the compressor 11 stabilizes at a value lower than that before the change in output frequency.

[0035] Therefore, the control unit 24 can be configured to change the above-mentioned determination threshold in response to a change in the output frequency of the inverter 25. For example, the control unit 24 can be configured to wait for the drive current value of the compressor 11 to stabilize after changing the output frequency of the inverter 25, and set the determination threshold in response to the drive current value after stabilization.

[0036] The control unit 24 may be configured to notify the user of the remaining time (remaining life) until the compressor 11 becomes unusable based on the drive current value of the compressor 11. Here, the state in which the compressor 11 becomes unusable (i.e., a fault state) is a state in which the drive current value of the compressor 11 reaches an upper limit, i.e., an overcurrent threshold. During the period from when an initial abnormality occurs in the compressor 11 until the compressor 11 becomes unusable, the amount by which the drive current value deviates from the normal range gradually increases as the galling of the compressor 11 bearings worsens and the amount of lubricating oil decreases, as illustrated in FIG. 9 . Furthermore, the frequency of occurrence of the phenomenon in which the drive current value deviates from the normal range gradually tends to increase.

[0037] The elapsed time (usage time of compressor 11) when the drive current value deviates from the normal range toward the large side for the nth time is defined as Tn, and the drive current value at elapsed time Tn is defined as In. Furthermore, the normal drive current value when compressor 11 is driven at the frequency of inverter 25 at elapsed time Tn is defined as Is. Tn, In, and Is may have a relationship represented by an exponential approximation curve, as shown in equation (1), where a and b are constants.

[0038]

number

[0039] The constants a and b in equation (1) are stored in the control unit 24, and each time the drive current value deviates from the normal range, the constants a and b can be updated based on the values ​​of T1 to Tn and I1 to In. Furthermore, the normal value Is of the drive current value at elapsed time Tn can be updated each time the frequency of the inverter 25 changes. An overcurrent threshold Ie can be set in advance as the upper limit of the drive current value of the compressor 11 and stored in the control unit 24. Tn obtained by substituting Ie for In in equation (1) calculated when the drive current value deviates for the nth time is defined as Te. If the remaining life until the compressor 11 becomes unusable is L, L can be given by equation (2).

[0040] L = Te - Tn (2) Below, an exposure apparatus incorporating the refrigeration apparatus 10 will be described as an example of a lithography apparatus, production apparatus, or industrial apparatus incorporating the refrigeration apparatus 10. An exposure apparatus is an apparatus used in a lithography process in the manufacturing process of devices or articles such as semiconductor devices or flat panel displays (FPDs). An exposure apparatus is an apparatus that performs an operation to transfer a pattern onto a substrate. More specifically, an exposure apparatus forms a latent image pattern on a substrate by transferring a pattern on a mask (original) onto a substrate coated with resist. Although a step-and-scan exposure apparatus will be described below, the exposure apparatus may also be an exposure apparatus using other exposure methods, such as a step-and-repeat method.

[0041] 10 shows the configuration of an exposure apparatus 100 in one embodiment. The exposure apparatus 100 may include a light source 101, an illumination optical system 102, a mask stage 103, a projection optical system 104, a substrate stage 105, and a refrigeration apparatus 10. The mask stage 103 is a stage that can hold and move a mask M. The substrate stage 105 is a stage that can hold and move a substrate W. The mask M and the substrate W are positioned at optically conjugate positions via the projection optical system 104. Light emitted from the light source 101 illuminates the mask M via the illumination optical system 102, and the pattern of the mask M is projected onto the substrate W, thereby performing an exposure process that forms a latent image pattern in a resist layer on the substrate W.

[0042] When exposure processing is performed in exposure apparatus 100, heat is generated in each part of exposure apparatus 100. For example, when exposure light is irradiated onto optical components constituting projection optical system 104, some of the energy of the exposure light is absorbed, generating heat within projection optical system 104. Furthermore, during exposure processing, the substrate stage 105 is driven to change the exposure area, and heat is generated in components such as a linear motor for driving the stage. The heat generated in each part of exposure apparatus 100 can cause a decrease in exposure performance, so it is cooled by refrigeration device 10 to maintain the temperature within an appropriate range.

[0043] The refrigeration device 10 is disposed in the exposure apparatus 100 so as to recover at least a portion of the heat generated during the operation for transferring a pattern onto a substrate. The refrigeration device 10 can perform cooling by heat exchange between the evaporator 14 in Figure 1 and the object to be cooled in the exposure apparatus 100. Because the amount of heat generated in the exposure apparatus 100 is large, the amount of heat exchanged in the evaporator 14 is also large, and a blower 106 with high blowing capacity is required in the machine room 107. Furthermore, because the transfer robot 108 for the substrate W is also large, the refrigeration device 10 is installed in a location where there is a lot of environmental noise, such as vibration and noise.

[0044] If the compressor 11 of the refrigeration device 10 stops operating, the heat generated by the exposure apparatus 100 cannot be cooled, which will lead to defects in the products produced, and therefore the operation of the exposure apparatus 100 must be stopped. Therefore, by using the above-described refrigeration device 10, it is possible to detect initial abnormalities in the compressor 11 at an early stage, thereby shortening the time that the apparatus is shut down and preventing a decrease in productivity due to a compressor abnormality.

[0045] A plurality of refrigeration devices 10 may be arranged in exposure apparatus 100. Each part of exposure apparatus 100 is controlled by a main control unit (not shown), and control of refrigeration devices 10 may also be controlled by the main control unit instead of control unit 24.

[0046] Below, an article manufacturing method for manufacturing an article using a lithography apparatus, such as the exposure apparatus 100 described above, will be described. The article manufacturing method may include a transfer step in which a pattern is transferred to a substrate using the lithography apparatus, and a processing step in which the substrate that has undergone the transfer step is processed to obtain an article. In the transfer step, a latent image pattern may be formed in a photosensitive agent coated on the substrate by exposure using the exposure apparatus described above. In the processing step, a physical pattern may be formed by developing the latent image pattern. The processing step may further include various other steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.).

[0047] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0048] 10: Refrigeration device, 11: Compressor, 12: Condenser, 13: Expansion valve, 14: Evaporator, 15: Flow control valve, 20: Refrigerant circuit, 21: High pressure acquisition unit, 22: Low pressure acquisition unit, 23: Current acquisition unit

Claims

1. a refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator; a detector for detecting a state of the refrigerant in the refrigerant circuit; an acquisition unit that acquires a drive current value of the compressor; a control unit that determines a state of the compressor; an inverter that drives the compressor, The control unit When the output of the detector is normal and the drive current value acquired by the acquisition unit exceeds a determination threshold, it is determined that a bearing of the compressor has an abnormality; awaiting the drive current value to stabilize after changing the output frequency of the inverter, and setting the determination threshold value according to the drive current value after stabilization; A refrigeration device characterized by:

2. The judgment threshold value is determined so as to be able to determine whether the bearing is suffering from galling.

2. The refrigeration system according to claim 1.

3. The judgment threshold value is determined so as to be able to determine a state in which the shaft supported by the bearing is rotatable but the bearing is causing galling.

2. The refrigeration system according to claim 1.

4. The control unit issues a notification when it is determined that the compressor has an abnormality.

4. The refrigeration system according to claim 1, wherein the refrigeration system is a refrigeration system.

5. the control unit determines a frequency at which the drive current value indicates an abnormality, and the notification includes providing information according to the frequency.

5. The refrigeration system according to claim 4.

6. the control unit determines the degree of the abnormality based on the magnitude of the drive current value, and the notification includes providing information according to the degree.

5. The refrigeration system according to claim 4.

7. the detector detects the pressure of the refrigerant in the refrigerant circuit as the state of the refrigerant in the refrigerant circuit.

7. The refrigeration system according to claim 1, wherein the refrigeration system is a refrigeration system.

8. the control unit notifies the user of a remaining period until the compressor becomes unusable based on the drive current value.

8. The refrigeration system according to claim 1, wherein the refrigeration system is a refrigerating device.

9. 1. A lithographic apparatus operable to transfer a pattern onto a substrate, the apparatus comprising: A refrigerator comprising the refrigeration device according to any one of claims 1 to 8, the refrigeration device is configured to recover at least a portion of the heat generated during the operation.

1. A lithography apparatus comprising:

10. a transfer step of transferring a pattern onto a substrate using the lithographic apparatus of claim 9; a processing step of processing the substrate that has undergone the transfer step to obtain an article; A method for manufacturing an article, comprising:

11. A control device connected to a refrigeration device, The refrigeration device is a refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator; a detector for detecting a state of the refrigerant in the refrigerant circuit; an acquisition unit that acquires a drive current value of the compressor; an inverter that drives the compressor, The control device includes a control unit that determines a state of the compressor, The control unit determining that a bearing of the compressor is abnormal when the output of the detector is within a normal range and the drive current value acquired by the acquisition unit exceeds a determination threshold; awaiting the drive current value to stabilize after changing the output frequency of the inverter, and setting the determination threshold value according to the drive current value after stabilization; A control device characterized by:

12. The judgment threshold value is determined so as to be able to determine whether the bearing is suffering from galling. The control device according to claim 11 .

13. The judgment threshold value is determined so as to be able to determine a state in which the shaft supported by the bearing is rotatable but the bearing is causing galling. The control device according to claim 11 .

14. A control method for controlling a refrigeration device having a refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator, comprising: a detection step of detecting a state of the refrigerant in the refrigerant circuit; an acquisition step of acquiring a drive current value of the compressor; a setting step of setting a judgment threshold; a determination step of determining a state of the compressor, The compressor is driven by an inverter, In the determination step, when the state of the refrigerant detected in the detection step is within a normal range and the drive current value acquired in the acquisition step exceeds the determination threshold, it is determined that a bearing of the compressor has an abnormality; the setting step waits for the drive current value to stabilize after changing the output frequency of the inverter, and sets the determination threshold value according to the drive current value after stabilization. A control method comprising:

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