Vacuum pump and vacuum pump control device

Abstract

A vacuum pump and a vacuum pump control device are provided, which can accurately determine the timing of replacing a rotary wing by creating an index that can quantitatively and easily determine the fatigue degree of a rotary wing. The motor current value output from a motor drive control unit (5) is input to a time counting processing unit (13), and in the time counting processing unit (13), the time that the current value of a rotating body (103) stays within the range of the stage at each stage of the current value is accumulated. In addition, the rotary wing temperature value output from a rotary wing temperature measuring unit (7) is input to the time counting processing unit (13). And the average value within one minute of the sampled rotary wing temperature value is taken. Thereafter, the time that the average value stays within the range at each stage of the rotary wing temperature value is accumulated. Each time value accumulated by the time counting processing unit (13) is stored in a memory (15). The storage processing unit (17) reads data from the memory (15) and stores it in a non-volatile memory (19).

Description

Technical Field

[0001] The present invention relates to a vacuum pump and a control device for the vacuum pump, and in particular to a vacuum pump and a control device for the vacuum pump that can accurately determine the timing of replacing a rotor blade by creating an index that can quantitatively and easily determine the fatigue degree of the rotor blade. Background Art

[0002] With the development of electronic technology in recent years, the demand for semiconductors such as memories and integrated circuits has increased rapidly.

[0003] These semiconductors are manufactured by doping impurities into a semiconductor substrate of extremely high purity to impart electrical properties thereto, or by forming fine circuits on a semiconductor substrate by etching.

[0004] Furthermore, these operations need to be performed in a high vacuum chamber to avoid the effects of dust in the air. To exhaust the chamber, a vacuum pump is generally used, and a turbomolecular pump is often used as one of the vacuum pumps because of the small amount of residual gas and easy maintenance.

[0005] Furthermore, in the semiconductor manufacturing process, there are many steps in which various process gases are applied to a semiconductor substrate, and a turbomolecular pump is used not only to create a vacuum in a chamber but also to exhaust these process gases from the chamber.

[0006] However, the process gas is sometimes introduced into the chamber in a high temperature state in order to increase reactivity.

[0007] Furthermore, these process gases are sometimes cooled when being exhausted and become solid at a certain temperature, and the product precipitates in the exhaust system. Furthermore, these process gases sometimes become solid at a low temperature in the turbomolecular pump and adhere to and accumulate inside the turbomolecular pump.

[0008] If precipitates of the process gas are deposited inside the turbomolecular pump, the deposits narrow the pump flow path, causing the performance of the turbomolecular pump to deteriorate.

[0009] In order to solve this problem, in the past, a heater or an annular water-cooling tube was wound around the periphery of the base part of the turbomolecular pump, and a temperature sensor was embedded in the base part, for example. The heating of the heater or the cooling of the water-cooling tube was controlled based on the signal of the temperature sensor to keep the temperature of the base part at a high temperature within a certain range (see Patent Document 1, Patent Document 2, and Patent Document 3).

[0010] Since the product is less likely to accumulate as the control temperature is higher, it is desirable to increase the temperature as much as possible.

[0011] On the other hand, when the base portion is heated to a high temperature as described above, the rotor blade may exceed the critical temperature due to fluctuations in the exhaust load or a high ambient temperature.

[0012] In order to prevent such disadvantages, a radioactive thermometer, for example, is installed in the base to regularly measure the temperature of the rotor blade. If the temperature exceeds a predetermined threshold for a certain period of time and the system is operated, a warning is issued. Furthermore, if the system continues to operate in a state where the temperature exceeds the threshold, for example, for about 30 seconds, the pump is stopped.

[0013] Furthermore, once the pump is started under these operations, it will continue to operate for, for example, 1 to 5 years, and there is little chance that it will be stopped except during major maintenance of the pump.

[0014] Therefore, the necessity of rotor blade replacement is usually determined during the overhaul of the turbomolecular pump. In addition to visual damage and discoloration, the accumulated operation time of the pump recorded in the control circuit is also used as a judgment item.

[0015] Patent Document 1: Japanese Patent Application Publication No. 2002-257079.

[0016] Patent document 2: Japanese Patent No. 5782378.

[0017] Patent document 3: WO2010 / 021307A1.

[0018] However, even for rotors with the same cumulative operating time, the stresses acting on the rotors due to the gas load during operation are actually different, so the degree of fatigue of the rotors may be greatly different. In addition, the temperature during operation cannot be ignored. The higher the temperature at which the rotor is operated, the greater the degree of fatigue of the rotor.

[0019] The information on the accumulated operation time of the pump recorded in the control circuit does not include the information on the gas load and temperature, so the necessity of rotor replacement can only be determined with such accuracy.

[0020] As a result, manufacturers will recommend early replacement based on safety considerations, but it is not easy to convince customers.

[0021] In addition, the above-mentioned judgment items alone may not be sufficient to properly judge the fatigue degree of the rotor blade. For example, if a situation occurs in which the temperature repeatedly exceeds or falls below the threshold value within 30 seconds, even if a pump abnormality cannot be detected, it is estimated that a considerable degree of fatigue has accumulated in the rotor blade.

[0022] Furthermore, if the temperature sensor samples the data every 0.5 seconds, the temperature data will continue to be accumulated during the operation of 1 to 5 years, which will become a huge amount of data. The load required to analyze this amount of data is also huge. Therefore, it is desirable to analyze the fatigue degree of the rotor blade without applying excessive load to the CPU mounted on the control circuit.

[0023] Therefore, it is desirable to create an index that can quantitatively and easily determine the degree of fatigue of the rotor in addition to the cumulative operating time. Summary of the invention

[0024] The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a vacuum pump and a control device for the vacuum pump, which can accurately determine the timing of replacing the rotor blades by creating an index that can quantitatively and easily determine the fatigue degree of the rotor blades.

[0025] To this end, the present invention (technical solution 1) is a vacuum pump capable of determining the timing of replacing a rotary blade, the vacuum pump comprising: a rotary blade built into a vacuum pump body; a sensor disposed in the vacuum pump body for measuring a physical quantity associated with the rotary blade, the vacuum pump comprising: a physical quantity extraction mechanism for extracting the physical quantity measured by the sensor during operation of the vacuum pump; a setting mechanism for presetting a variation range of the physical quantity extracted by the physical quantity extraction mechanism to a plurality of stages; a time acquisition mechanism for acquiring the total time when the physical quantity belongs to each of the aforementioned stages and the total time of the entire stage during operation of the vacuum pump; a storage mechanism for storing the total time of each of the aforementioned stages obtained by the time acquisition mechanism and the total time of the aforementioned entire stage; and a display mechanism for displaying the total time of each of the aforementioned stages stored by the storage mechanism, or the ratio of the total time of each of the aforementioned stages to the total time of the aforementioned entire stage.

[0026] The physical quantity related to the rotor measured by the sensor is extracted. The variation range of the physical quantity is pre-set to multiple stages in the setting mechanism. In addition, the total time of the physical quantity belonging to each stage and the total time of the entire stage are obtained. The total time of each stage obtained and the ratio of the total time of each stage to the total time of the entire stage are displayed.

[0027] Thus, the necessity of replacing the rotor blades can be objectively and accurately determined using only a small numerical value such as the cumulative time or ratio of each stage of the physical quantity. In addition, the amount of precipitates of the process gas accumulated inside the vacuum pump can also be used as an indicator using this numerical value.

[0028] Furthermore, the present invention (technical solution 2) is configured to include: a comparing means for comparing the total time of each of the stages acquired by the time acquiring means with a predetermined threshold value; and a warning issuing means for issuing a warning based on the comparison result of the comparing means.

[0029] Whether or not overhaul is required can be determined from the accumulated value of the counted time, and a notice urging the overhaul of the rotor can be issued. By issuing a warning notice urging the overhaul in this way, it is expected that the rotor damage accident can be prevented.

[0030] Furthermore, the present invention (technical solution 3) is characterized in that the sensor is a temperature measuring mechanism for measuring the temperature of the rotor blade built into the vacuum pump body, or a current measuring mechanism for measuring the current flowing through a motor driving the rotor blade.

[0031] The temperature measuring mechanism and the current measuring mechanism are used for the protection function of the pump. In addition to the protection function, they are also used to determine the time for the overhaul of the rotor blades.

[0032] Furthermore, the present invention (technical solution 4) is a control device for a vacuum pump, the vacuum pump comprising: a rotary blade, which is built into a vacuum pump body; a sensor, which is arranged in the vacuum pump body and measures a physical quantity associated with the rotary blade, and is characterized in that it comprises: a physical quantity extraction mechanism, which extracts the physical quantity measured by the sensor during the operation of the vacuum pump; a setting mechanism, which pre-sets the variation range of the physical quantity extracted by the physical quantity extraction mechanism to multiple stages; a time acquisition mechanism, which acquires the total time when the physical quantity belongs to each of the aforementioned stages and the total time of the entire stage during the operation of the vacuum pump; a storage mechanism, which stores the total time of each of the aforementioned stages acquired by the time acquisition mechanism and the total time of the aforementioned entire stage; a display mechanism, which displays the total time of each of the aforementioned stages stored by the storage mechanism, or the ratio of the total time of each of the aforementioned stages to the total time of the aforementioned entire stage, and can judge the timing of replacing the rotary blade based on the total time of each of the aforementioned stages or the aforementioned ratio displayed by the display mechanism.

[0033] According to the present invention (technical solution 1) as described above, the time acquisition means acquires the total time of the physical quantity belonging to each stage and the total time of the entire stage during the operation of the vacuum pump, and displays the total time of each stage, or displays the ratio of the total time of each stage to the total time of the entire stage. Therefore, the necessity of replacing the rotor blade can be objectively and correctly determined only by a small numerical value such as the cumulative time or ratio of each stage of the physical quantity. In addition, the numerical value can also be used as an indicator of the amount of precipitates of the process gas accumulated inside the vacuum pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A system configuration diagram for determining the necessity of rotor blade replacement according to an embodiment of the present invention

[0035] Figure 2 This is the structure diagram of the turbomolecular pump

[0036] Figure 3 This is a flowchart for determining the necessity of rotor blade replacement according to the present embodiment.

[0037] Figure 4 is the motor drive current time sub-process

[0038] Figure 5 is the wing temperature time subprocess

[0039] Figure 6 This is an example of setting the rotor temperature value to five levels.

[0040] Figure 7 The flowchart shows a method of notifying a warning urging an overhaul. DETAILED DESCRIPTION

[0041] Hereinafter, embodiments of the present invention will be described. Figure 1 A system configuration diagram for determining the necessity of rotor blade replacement according to an embodiment of the present invention is shown. Figure 2 A structural diagram of a turbomolecular pump is shown.

[0042] exist Figure 1 In the embodiment, the control device 200 is described as being separate from the pump body 100 , but the present embodiment is applicable even if the pump body 100 and the control device 200 are integrated into one turbomolecular pump.

[0043] The control device 200 is provided with a magnetic bearing control unit 3 for controlling the suspension of the magnetic bearings (104, 105, 106) provided in the pump body 100, and a motor drive control unit 5 for controlling the rotation of the motor 121. The rotor temperature measuring unit 7 receives a signal obtained by contactlessly measuring the temperature of the rotating body 103 by the rotor temperature sensor 9. The suspension position of the rotating body 103 and the like are output from the magnetic bearing control unit 3 and input to the protection function processing unit 11. In addition, when the suspension position of the rotating body 103 and the like are abnormal, the protection function processing unit 11 issues a warning and stops the pump.

[0044] The rotation speed value and the motor current value of the rotating body 103 are output from the motor drive control unit 5 and input to the protection function processing unit 11. When the rotation speed value and the motor current value of the rotating body 103 are abnormal, a warning is issued and the pump is stopped in the protection function processing unit 11. In addition, the motor current value output from the motor drive control unit 5 is input to the time counting processing unit 13, and in the time counting processing unit 13, for each stage of the current value, the time that the current value of the rotating body 103 stays within the range of the stage is accumulated.

[0045] The rotor temperature value is output from the rotor temperature measuring unit 7 and input to the protection function processing unit 11. When the rotor temperature value is abnormal, the protection function processing unit 11 issues a warning and stops the pump. In addition, the rotor temperature value output from the rotor temperature measuring unit 7 is input to the time counting processing unit 13. The sampled rotor temperature value is averaged for one minute. After that, the time that the average value stays within the range is accumulated for each stage of the rotor temperature value.

[0046] The time values ​​accumulated by the time counting processing unit 13 are stored in the memory 15. The storage processing unit 17 reads data from the memory 15 and stores it in the nonvolatile memory 19, for example, when the pump is decelerated and stopped or every two hours.

[0047] exist Figure 2 In the embodiment, an air intake port 101 is formed at the upper end of a cylindrical outer cylinder 127 of a pump body 100. A rotating body 103 is provided inside the outer cylinder 127, and a plurality of rotating wings 102a, 102b, 102c, etc. based on turbine wings for sucking and exhausting gas are radially and multi-stagedly formed on the periphery of the rotating body 103.

[0048] A rotor shaft 113 is mounted at the center of the rotating body 103 . The rotor shaft 113 is suspended and supported in mid-air by, for example, a magnetic bearing for so-called five-axis control, and its position is controlled.

[0049] The upper radial electromagnets 104 are four electromagnets arranged in pairs on the X-axis and the Y-axis which are orthogonal to each other as the radial coordinate axes of the rotor shaft 113. An upper radial sensor 107 composed of four electromagnets is provided close to and corresponding to the upper radial electromagnets 104. The upper radial sensor 107 is configured to detect the radial displacement of the rotor shaft 113 and transmit it to the control device 200.

[0050] In the magnetic bearing control unit 3 of the control device 200 , based on the displacement signal detected by the upper radial sensor 107 , the excitation of the upper radial electromagnet 104 is controlled via a compensation circuit having a PID adjustment function to adjust the upper radial position of the rotor shaft 113 .

[0051] The rotor shaft 113 is formed of a high magnetic permeability material (iron, etc.) and is attracted by the magnetic force of the upper radial electromagnet 104. The relevant adjustments are performed independently in the X-axis direction and the Y-axis direction.

[0052] The lower radial electromagnet 105 and the lower radial sensor 108 are arranged similarly to the upper radial electromagnet 104 and the upper radial sensor 107 , and the lower radial position of the rotor shaft 113 is adjusted similarly to the upper radial position by the magnetic bearing control unit 3 .

[0053] Furthermore, the axial electromagnets 106A and 106B are arranged to clamp the disc-shaped metal disk 111 provided at the lower part of the rotor shaft 113 from top to bottom. The metal disk 111 is made of a high magnetic permeability material such as iron. An axial sensor (not shown) for detecting the axial displacement of the rotor shaft 113 is provided. The axial displacement signal is transmitted to the magnetic bearing control unit 3 of the control device 200.

[0054] Then, the axial electromagnets 106A and 106B are subjected to excitation control based on the axial displacement signal via a compensation circuit having a PID adjustment function of the magnetic bearing control unit 3. The axial electromagnets 106A and 106B attract the metal disk 111 upward and downward respectively by magnetic force.

[0055] In this manner, the magnetic bearing control unit 3 of the control device 200 appropriately adjusts the magnetic force applied to the metal disk 111 by the axial electromagnets 106A and 106B, so that the rotor shaft 113 is magnetically levitated in the axial direction and held in space in a non-contact manner.

[0056] The motor 121 includes a plurality of magnetic poles that are circumferentially arranged to surround the rotor shaft 113. Each magnetic pole is controlled by the motor drive control unit 5 so as to rotationally drive the rotor shaft 113 via an electromagnetic force acting between the magnetic poles and the rotor shaft 113.

[0057] A plurality of fixed wings 123a, 123b, 123c, ... are provided with a small gap from the rotating wings 102a, 102b, 102c, ... The rotating wings 102a, 102b, 102c, ... are formed to be inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to transfer exhaust gas molecules downward by collision.

[0058] Furthermore, the fixed blades 123 are similarly formed to be inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 , and are arranged to face the inside of the outer cylinder 127 and to intersect with the stages of the rotary blades 102 .

[0059] Furthermore, one end of the fixing wing 123 is supported in a state of being inserted between a plurality of stacked fixing wing spacers 125a, 125b, 125c, ...

[0060] The fixed blade spacer 125 is an annular member, and is made of a metal such as aluminum, iron, stainless steel, copper, or an alloy containing these metals as a component.

[0061] An outer cylinder 127 is fixed with a small gap on the outer periphery of the fixed wing spacer 125. A base portion 129 is provided at the bottom of the outer cylinder 127, and a threaded spacer 131 is provided between the lower portion of the fixed wing spacer 125 and the base portion 129. An exhaust port 133 is formed at the lower portion of the threaded spacer 131 in the base portion 129, and communicates with the outside.

[0062] The threaded spacer 131 is a cylindrical member made of a metal such as aluminum, copper, stainless steel, iron, or an alloy of these metals, and has a plurality of spiral thread grooves 131 a engraved on its inner circumference.

[0063] The spiral direction of the screw groove 131 a is a direction in which, when the molecules of the exhaust gas move in the rotation direction of the rotating body 103 , the molecules are transferred toward the exhaust port 133 .

[0064] A cylindrical portion 102d is suspended from the lowest part of the rotating wings 102a, 102b, 102c, ... connected to the rotating body 103. The outer peripheral surface of the cylindrical portion 102d is cylindrical and protrudes toward the inner peripheral surface of the threaded spacer 131, and is close to the inner peripheral surface of the threaded spacer 131 with a predetermined gap.

[0065] The base portion 129 is a disc-shaped member constituting the base portion of the pump body 100 of the turbomolecular pump, and is generally made of metal such as iron, aluminum, or stainless steel.

[0066] The base portion 129 physically holds the pump body 100 and also functions as a heat conduction path, and therefore it is desirable to use a metal having rigidity and high thermal conductivity, such as iron, aluminum, or copper.

[0067] In this structure, when the rotary blade 102 is driven by the motor 121 to rotate together with the rotor shaft 113 , the exhaust gas from the chamber is sucked through the suction port 101 by the action of the rotary blade 102 and the fixed blade 123 .

[0068] The exhaust gas sucked from the air intake port 101 passes between the rotary blade 102 and the fixed blade 123 and is transferred to the base portion 129. At this time, the temperature of the rotary blade 102 rises due to frictional heat generated when the exhaust gas contacts or collides with the rotary blade 102, conduction and radiation of heat generated by the motor 121, and the heat is transferred to the fixed blade 123 side by radiation or conduction based on gas molecules of the exhaust gas.

[0069] The fixed blade spacers 125 are joined to each other at the outer circumference, and the fixed blades 123 transfer heat received from the rotary blades 102 and friction heat generated when the exhaust gas contacts or impacts the fixed blades 123 to the outer cylinder 127 and the threaded spacers 131 .

[0070] The exhaust gas transferred to the threaded spacer 131 is sent out to the exhaust port 133 while being guided to the thread groove 131 a .

[0071] In addition, the electrical equipment part composed of the motor 121, the lower radial electromagnet 105, the lower radial sensor 108, the upper radial electromagnet 104, the upper radial sensor 107, etc. is covered by the stator column 122, and the electrical equipment part is maintained at a predetermined pressure by means of a purge gas so that the gas sucked in from the air intake port 101 does not invade the electrical equipment side.

[0072] The rotor temperature sensor 9 is provided at the outer diameter portion of the stator column 122 and in the vicinity of the exhaust port 133 .

[0073] Next, the operation of this embodiment will be described.

[0074] In the present embodiment, the accumulated operating time information is provided in order to create an index for determining whether to replace the rotor.

[0075] And, as the accumulated operation time information, the time that satisfies a specific condition is defined, and the accumulated time is recorded. Specifically, the following two conditions are set.

[0076] (1) Regarding the current value supplied to the motor 121 that can determine the tendency of the gas load, the cumulative time during which the current value exceeds a certain predetermined value is recorded.

[0077] (2) Regarding the temperature value of rotor blade 102 used for abnormality detection, the cumulative time during which the temperature value exceeds a certain prescribed value is recorded.

[0078] In recent semiconductor process equipment, turbomolecular pumps are used in complex processes. Therefore, in order to show the trend of the usage status, the above-mentioned predetermined value is set in a plurality of stages, and the cumulative value of the time spent in each stage is recorded.

[0079] For example, as the level of the current value supplied to the motor 121, three levels of more / middle / less are set in the order of the current value. Here, the three levels of more / middle / less are set for easy understanding of the description, and it is desirable to set more levels. In this regard, the setting of the rotor temperature value described later is also the same.

[0080] "More" is a range of current values ​​that are not expected for normal operation, including the level of alarm and the level of abnormality, where the current value is large. For example, if the state of exceeding the specified current value continues for 30 seconds, it becomes a condition for alarm and pump operation to stop. Therefore, if the time staying at the level of alarm and the level of abnormality is a short time such as a few seconds, the alarm and pump will not be stopped. However, if an abnormally large load is applied and such a situation is repeatedly accumulated, it is estimated that the rotor 102 is fatigued. The degree of fatigue of the rotor 102 can also be indexed by the accumulation of the time in "More".

[0081] "Medium" is the normal operating state of the pump, and is the range of current values ​​expected for operation. The range of current values ​​expected for the operation is determined for each pump. "Small" is a condition in which the load is light, or the rotating body 103 is magnetically suspended and the motor 121 does not rotate. When recording the cumulative value of the time spent in each stage, the cumulative operating time is set to 100%. For example, a pump with a record of [10% more / 70% medium / 20% less] can be judged to be used in an operating state in which the gas load fluctuates less and the load is not that large. On the other hand, a pump with a record of [50% more / 40% medium / 10% less] can be judged to be used in an operating state in which the gas load fluctuates more and the load is also large.

[0082] If the accumulated operation times are the same, it can be determined that the latter pump is the one with the greater fatigue degree of rotor 102. Even if the accumulated operation times are different, the accumulated time used when the supply current level is "high" can be recorded and the fatigue degree can be determined from this value.

[0083] Similarly, the rotor temperature value is set to three levels of high, medium, and low in the temperature range that does not cause abnormality detection, and the fatigue degree of the rotor 102 can be determined by recording the cumulative value of the time spent in each level.

[0084] Next, the operation of this embodiment will be described based on the flowchart.

[0085] Figure 3 The flow of the necessity determination of rotor blade replacement in this embodiment is shown. This flow is executed in the time counting processing unit 13. The time counting processing unit 13 corresponds to the time acquisition means.

[0086] exist Figure 3In step 1 (abbreviated as S1 in the figure, the same below), for example, a timer interrupt is performed every 1 minute, and the processing after step 2 is executed. In step 2, the value of the cumulative power-on time counter is accumulated. The accumulation is performed by adding 1 to the value of the cumulative power-on time counter (hereinafter referred to as increment) (hereinafter the same). The cumulative power-on time counter is a counter for the power-on time when the control power supply is energized, and is counted even when the rotary wing 102 is not rotating but is suspended and supported by the magnetic bearing control unit 3. The count value of the power-on time multiplied by the interruption time of the timer is equivalent to the total time of the entire stage. In step 3, it is determined whether the pump is rotating. When it is determined to be rotating, step 4 is entered to accumulate the cumulative operating time counter.

[0087] On the other hand, if it is determined in step 3 that the pump is not rotating, the process proceeds to the motor drive current time subroutine of step 10 to measure the cumulative time of the motor drive current in each stage. Thereafter, the process proceeds to the wing temperature time subroutine in step 20 to measure the cumulative time of the wing temperature in each stage. The cumulative time of the motor drive current in each stage and the cumulative time of the wing temperature in each stage correspond to the total time when the physical quantity belongs to each stage.

[0088] right Figure 4 The motor drive current-time sub-process is described below.

[0089] In step 11, it is determined whether the motor current value output from the motor drive control unit 5 is greater than a preset high level. And, if it is greater than the high level, the process proceeds to step 12, and the current "high" counter is accumulated and then the process proceeds to step 20. On the other hand, in step 11, when the motor current value is below the preset high level, the process proceeds to step 13, and it is determined whether the motor current value is greater than a preset medium level. And, if it is greater than the medium level, the process proceeds to step 14, and the current "medium" counter is accumulated and then the process proceeds to step 20. On the other hand, in step 13, when the motor current value is below the preset medium level, the process proceeds to step 20.

[0090] The current “small” is not counted because it can be obtained by subtracting the count value of the current “large” counter and the count value of the current “medium” counter from the count value of the cumulative energization time counter.

[0091] Thus, every one minute, it is determined whether the measured motor current value is in one of the stages of current "high", current "medium", and current "low", and the value is accumulated by incrementing the value in that stage.

[0092] If the count value is multiplied by 1 minute, the accumulated time can be calculated. The time data is displayed in each stage. In addition, the total time of these entire stages can be calculated as 100% and the ratio of the accumulated time in each stage can be displayed.

[0093] Thus, the necessity of replacing the rotor blade 102 can be objectively and accurately determined using only three numerical values ​​of the accumulated time or ratio of each of the current "high", current "medium", and current "low". In addition, this numerical value can also be used as an indicator of the amount of precipitates of the process gas deposited in the turbomolecular pump.

[0094] Next, Figure 5 The wing temperature-time sub-process is described.

[0095] In step 21, it is determined whether the rotary wing temperature value output from the rotary wing temperature measuring unit 7 is higher than the pre-set high-level temperature value. And, if it is higher than the high-level temperature value, the process proceeds to step 22, and the wing temperature "high" counter is accumulated. Then, the process proceeds to step 30, and the timer interrupt processing ends. On the other hand, in step 21, when the rotary wing temperature value is below the pre-set high-level temperature value, the process proceeds to step 23, and it is determined whether the rotary wing temperature value is higher than the pre-set medium-level temperature value. And, if it is higher than the medium-level temperature value, the process proceeds to step 24, and the wing temperature "medium" counter is accumulated. Then, the process proceeds to step 30, and the timer interrupt processing ends. On the other hand, in step 23, when the rotary wing temperature value is below the pre-set medium-level temperature value, the process proceeds to step 30, and the timer interrupt processing ends.

[0096] The wing temperature "low" is not counted because it can be obtained by subtracting the count value of the wing temperature "high" counter and the count value of the wing temperature "medium" counter from the count value of the accumulated power-on time counter.

[0097] Thus, every minute, it is determined whether the measured rotor blade temperature value is in one of the stages of blade temperature "high", blade temperature "medium", and blade temperature "low", and the accumulation is performed by incrementing the value for that stage.

[0098] Therefore, similarly to the case of the motor current value, only three values ​​of the accumulated time or ratio of each of the wing temperature "high", wing temperature "medium", and wing temperature "low" can be used to objectively and accurately determine the necessity of replacing the rotor 102. In addition, these data can also be used as information to persuade customers.

[0099] The rotor temperature values ​​are compared using three phases Figure 5 The wing temperature time subprocess is described, but Figure 6 An example is shown in which the rotor temperature value is set to five stages.

[0100] exist Figure 6 In the embodiment, regarding the rotor temperature value, the temperature for high temperature overheat warning detection is set to, for example, 135°C. When this temperature is reached, a warning is issued. The warning is released with a hysteresis, so it is set to 130°C. In addition, the temperature for high temperature overheat abnormality detection is set to, for example, 145°C. When this temperature is reached, a pump stop command is issued after, for example, this state continues for 30 seconds. The abnormality is released with a hysteresis, so it is set to 140°C.

[0101] Here, the level of the wing temperature counter is prepared in five stages in the form corresponding to the temperature value set for the safety management of the rotor 102. That is, the temperature from 135°C for high temperature overheat warning detection to 145°C for high temperature overheat abnormality detection is set to level 4, and the temperature above 145°C for high temperature overheat abnormality detection is set to level 5. In addition, the rotor temperature value of 90°C or more and less than 135°C is set to level 3 because this temperature range is the expected operating range in pump operation. In addition, the rotor temperature value of 40°C or more and less than 90°C is set to level 2 because this temperature range is the range of operating conditions with no excessive load in operation and a relatively large margin. Furthermore, the rotor temperature value of less than 40°C is set to level 1 because in this temperature range, the rotor 102 is in a state of floating in a magnetic suspension state without rotating.

[0102] By setting the rotor temperature value to five levels in this way, it is possible to more objectively and accurately determine the necessity of replacement of the rotor 102. In this regard, by further increasing the number of levels, a more objective and accurate determination can be made.

[0103] Next, based on Figure 7 The method of issuing a warning to urge overhaul is described. Figure 4 The same elements are denoted by the same reference numerals and their descriptions are omitted. Figure 7 In step 12, after the current "more" counter is accumulated, step 15 is entered. In step 15, it is determined whether the count value of the current "more" counter exceeds a predetermined warning threshold. And, in the case of exceeding the warning threshold, a large warning notification of rotating body fatigue is issued in step 16.

[0104] Thus, it is possible to judge whether overhaul is required from the count value of the current "high" counter every minute, and issue a notice to urge overhaul. By issuing a warning to urge overhaul in this way, it is possible to expect the prevention of rotating body damage accidents.

[0105] In addition, the present invention can be modified in various ways without departing from the gist of the present invention, and the present invention naturally includes the contents of such modifications.

[0106] Reference numerals

[0107] 3 Magnetic bearing control unit

[0108] 5 Motor drive control unit

[0109] 7 Rotor temperature measurement unit

[0110] 9 Rotor temperature sensor

[0111] 11 Protection function processing unit

[0112] 13. Time counting processing unit (time acquisition mechanism)

[0113] 15 Memory

[0114] 17 Storage Processing Unit

[0115] 19 Non-volatile memory

[0116] 100 Pump body

[0117] 102 Rotary Wing

[0118] 103 Rotating body

[0119] 104 Upper radial electromagnet

[0120] 105 Lower radial electromagnet

[0121] 106A, 106B Axial Electromagnet

[0122] 121 Motor

[0123] 200 Control device.

Claims

1. A vacuum pump capable of determining when to replace a rotor blade. The vacuum pump comprises: a rotary blade built into a vacuum pump body; and a sensor disposed in the vacuum pump body to measure a physical quantity associated with the rotary blade. in, have: A physical quantity extraction mechanism for extracting the physical quantity measured by the sensor during the operation of the vacuum pump; a setting means for presetting the variation range of the aforementioned physical quantity extracted by the physical quantity extraction means into a plurality of stages; A time acquisition means for acquiring, during the operation of the vacuum pump, the total time of the physical quantity belonging to each of the aforementioned stages and the total time of the entire stage; The preservation agency shall preserve the total time of each of the aforementioned stages and the total time of the aforementioned entire stage obtained by the time obtaining agency; a display unit for displaying the total time of each of the aforementioned stages stored by the storage unit, or the ratio of the total time of each of the aforementioned stages to the total time of the entire aforementioned stages, The sensor is a temperature measuring mechanism for measuring the temperature of the rotor blade and a current measuring mechanism for measuring the current flowing through a motor driving the rotor blade. Each of the aforementioned stages has a range of current values ​​measured by the aforementioned current measurement means, The total time in each of the stages is the total time during which the current value is within the range of the current value associated with each stage.

2. The vacuum pump according to claim 1, characterized in that The system comprises: a comparing unit for comparing the total time of each of the above-mentioned stages obtained by the above-mentioned time obtaining unit with a predetermined threshold value; and a warning issuing unit for issuing a warning based on the comparison result of the comparing unit.

3. A control device for a vacuum pump, the vacuum pump comprising: a rotary blade built into a vacuum pump body; A sensor is provided on the vacuum pump body to measure a physical quantity related to the rotor blade. in, have: A physical quantity extraction mechanism for extracting the physical quantity measured by the sensor during the operation of the vacuum pump; a setting means for presetting the variation range of the aforementioned physical quantity extracted by the physical quantity extraction means into a plurality of stages; A time acquisition means for acquiring, during the operation of the vacuum pump, the total time of the physical quantity belonging to each of the aforementioned stages and the total time of the entire stage; The preservation agency shall preserve the total time of each of the aforementioned stages and the total time of the aforementioned entire stage obtained by the time obtaining agency; a display unit for displaying the total time of each of the aforementioned stages stored by the storage unit, or the ratio of the total time of each of the aforementioned stages to the total time of the entire aforementioned stages, The sensor is a temperature measuring mechanism for measuring the temperature of the rotor blade and a current measuring mechanism for measuring the current flowing through a motor driving the rotor blade. Each of the aforementioned stages has a range of current values ​​measured by the aforementioned current measurement means, The total time of each of the above-mentioned stages is the total time when the above-mentioned current value is within the range of the current value related to each stage, The timing of replacing the rotor blade can be determined based on the total time of each stage or the ratio displayed by the display means.

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