JP2016098788A - Control device for vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of determination of a dew condensation state by reducing occurrence probability of erroneous detection.SOLUTION: A control device for a vacuum pump includes: a pump control unit for controlling a vacuum pump; a cooling device for cooling the pump control unit; a housing for accommodating the pump control unit; a temperature sensor for detecting one temperature out of the temperature in a first position and the temperature in a second position in which the temperature becomes higher than that in the first position in the housing; a humidity sensor for detecting humidity in the second position in the housing; a temperature estimation unit for estimating the other temperature out of the temperature in the first position and the temperature in the second position, based on the temperature detected by the temperature sensor; and a cooling control unit for controlling execution and stop of a cooling operation by the cooling device, based on the estimation temperature estimated by the temperature estimation unit, the temperature detected by the temperature sensor and the humidity detected by the humidity sensor.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control device for a vacuum pump.

  A vacuum pump used for evacuation of an external apparatus such as a semiconductor manufacturing apparatus includes a pump body and a control device that controls the pump body. The control device is cooled by a refrigerant such as cooling water. Usually, the control device has a semi-enclosed structure, and the dew point temperature inside the control device is the same as the outside of the control device, that is, outside air. For this reason, when the control device is cooled by the refrigerant, a portion where the temperature is locally lower than the dew point temperature occurs in the control device, which may cause condensation.

  In Patent Document 1, the first temperature detection means is provided in the low temperature part in the control device, the second temperature detection means and the humidity detection means are provided in the high temperature part in the control device, and the calculation is performed based on information detected by each detection means. There has been proposed a vacuum pump for controlling the operation of the cooling device based on the relative humidity of the low temperature portion.

JP 2014-43827 A

  However, the technique disclosed in Patent Document 1 has a problem in that the dew condensation state cannot be appropriately determined if any one of the three detection means (sensors) is erroneously detected.

A control device for a vacuum pump according to a preferred embodiment of the present invention includes a pump control unit that controls a vacuum pump, a cooling device that cools the pump control unit, a housing that houses the pump control unit, and a first inside the housing. A temperature sensor that detects the temperature at one of the position and the second position that is higher than the first position, a humidity sensor that detects the humidity at the second position in the housing, the first position and the first position A temperature estimation unit that estimates the temperature at the other of the two positions based on the temperature detected by the temperature sensor, an estimated temperature estimated by the temperature estimation unit, a temperature detected by the temperature sensor, and a humidity sensor And a cooling control unit that controls execution and stop of the cooling operation by the cooling device based on the humidity detected in step (b).
In a further preferred embodiment, the temperature estimation unit estimates the temperature of the second position by multiplying or adding a constant to the temperature of the first position detected by the temperature sensor, or detected by the temperature sensor. The temperature at the first position is estimated by dividing or subtracting a constant from the temperature at the second position.
In a more preferred embodiment, the cooling control unit determines that the condensation state is present when the humidity is higher than the predetermined humidity, and determines that the condensation control unit does not indicate the condensation state when the humidity is lower than the predetermined humidity. An operation control unit that stops the cooling operation when the state determined to be the dew condensation state is continued for a predetermined time, and the predetermined time is a time indicating that the temperature distribution in the housing is stable When set and the cooling operation is stopped, the operation control unit causes the cooling operation to be performed when the temperature in the housing becomes higher than the first temperature.
In a further preferred embodiment, when the cooling operation is being performed, the operation control unit determines whether or not the dew state is present until the temperature in the housing is lower than the second temperature lower than the first temperature. First, the cooling operation is performed, and when the temperature in the housing becomes lower than the second temperature, the cooling operation is stopped.
In a more preferred embodiment, the temperature estimation unit has a larger difference between the temperature detected by the temperature sensor and the estimated temperature when the cooling operation is being performed than when the cooling operation is stopped. Thus, the estimated temperature is estimated.
In a further preferred embodiment, the temperature estimation unit detects the temperature detected by the temperature sensor when the load of the motor driving the vacuum pump is higher than the predetermined load, compared to when the load of the motor is lower than the predetermined load. The estimated temperature is estimated so that the difference between the estimated temperature and the estimated temperature becomes large.
In a more preferred embodiment, the cooling device includes a flow path forming body that forms a cooling flow path for circulating a coolant that cools the pump control unit, and a metal substrate is connected to the flow path forming body so as to be thermally conductive. The temperature sensor is surface-mounted on the substrate that is the first position.

  According to the present invention, since the number of pieces of information to be detected can be reduced, it is possible to reduce the probability of erroneous detection and improve the reliability of the determination of the dew condensation state.

The figure which shows the turbo-molecular pump which concerns on 1st Embodiment. The schematic diagram which shows the position of the temperature sensor and humidity sensor in the control apparatus which concerns on 1st Embodiment. The functional block diagram which shows the structure of a turbo-molecular pump. The figure showing a saturated vapor pressure curve. The flowchart which showed the operation | movement of the solenoid valve switching process which concerns on 1st Embodiment. The flowchart which showed the operation | movement of the dew condensation state determination process which concerns on 1st Embodiment. The schematic diagram which shows the position of the temperature sensor and humidity sensor in the control apparatus which concerns on 2nd Embodiment. The flowchart which showed the operation | movement of the dew condensation state determination process which concerns on 2nd Embodiment. The flowchart which showed the operation | movement of the solenoid valve switching process which concerns on 3rd Embodiment.

Hereinafter, an embodiment of a vacuum pump will be described with reference to the drawings.
-First embodiment-
FIG. 1 is a diagram illustrating a turbo molecular pump 1 that is an example of a vacuum pump. For convenience of explanation, in this specification, the vertical direction is defined as shown in FIG.

  The turbo molecular pump 1 includes a pump body 10, a control device 40 that drives and controls the pump body 10, and a cooling device 50 that is disposed between the pump body 10 and the control device 40. By fixing the inlet flange 11 provided in the pump body 10 to a vacuum chamber of an external device (not shown) such as a semiconductor manufacturing device, a liquid crystal panel manufacturing device, or an analyzer, the turbo molecular pump 1 is connected to an external device (not shown). ). Inside the pump main body 10 are accommodated a rotating body (not shown) in which rotating blades are formed, and a motor (not shown in FIG. 1) that rotationally drives the rotating body. The rotating body is supported in a non-contact manner by an electromagnet constituting a magnetic bearing (not shown in FIG. 1).

  The pump body 10 includes a pump casing having an upper casing 20 and a lower casing 30 attached to the lower side of the upper casing 20. The upper casing 20 and the lower casing 30 are combined and integrated by fastening both flanges 21 and 31 with bolts.

  The flange 32 provided at the lower end of the lower casing 30 is fixed to the cooling block 51 of the cooling device 50 with bolts, whereby the lower casing 30 and the cooling block 51 are coupled and integrated. The housing 41 of the control device 40 is coupled to and integrated with the cooling block 51 by bolts. The casing 41 is formed in a substantially rectangular box shape having an opening at the top, and the opening at the top is closed by a cooling block 51. The housing 41 is configured to communicate with the outside, but has a semi-hermetic structure in which intrusion of liquid droplets and dust is prevented.

  The cooling device 50 is a device that cools the pump body 10 and the control device 40, and includes a cooling block 51, a cooling pipe 52, and a three-way valve 150. The cooling block 51 has a flat plate shape, and has an upper surface connected to the pump body 10 so as to be able to conduct heat and a lower surface connected to the control device 40 so as to be able to conduct heat. The cooling block 51 has a cooling pipe 52 disposed therein. The cooling pipe 52 forms a cooling flow path through which water flows as a refrigerant, and a refrigerant inlet portion 52 i and a refrigerant outlet portion 52 o are provided so as to protrude sideways from the cooling block 51.

  The three-way valve 150 is an electromagnetically driven switching valve that adjusts the flow rate of the refrigerant supplied to the cooling device 50. FIG. 2 is a schematic diagram showing the configuration of the cooling device 50 and the internal configuration of the control device 40. FIG. 2 shows the positions of the temperature sensor 160 and the humidity sensor 170 in the control device 40. As shown in FIG. 2, the three-way valve 150 is provided in the refrigerant inlet 52i and connected to the refrigerant outlet 52o via the bypass channel 52b.

  The three-way valve 150 is a switching position for supplying the refrigerant into the cooling block 51 (hereinafter referred to as a supply position), and a switching position for blocking the supply of the refrigerant into the cooling block 51 and supplying the refrigerant to the bypass passage 52b. (Hereinafter referred to as a detour position).

  A plurality of substrates 45 a, 45 b, 46 on which a plurality of electronic components are mounted are accommodated inside the casing 41 of the control device 40, and each electronic component is supplied with a coolant to the cooling block 51. To be cooled. Among the plurality of substrates 45a, 45b, 46, a power supply unit 151, a motor drive circuit 152, and a magnetic bearing drive circuit 153, which will be described later, are mounted on the substrates 45a, 45b, and a main control unit 140, which will be described later, A three-way valve drive circuit 154 is mounted.

  Electronic components (for example, field effect transistors (FETs), diodes, etc.) that generate a large amount of heat are mounted on the substrates 45a and 45b, and the electronic components mounted on the substrates 45a and 45b are mounted on the substrate 46. The temperature is higher than that of electronic components. The boards 45a and 45b are metal circuit boards, and are fixed to the cooling block 51 in a state where the boards 45a and 45b are connected to the lower surface of the cooling block 51 so as to conduct heat. Therefore, the substrates 45 a and 45 b are efficiently cooled by supplying the coolant into the cooling block 51. The substrate 46 is fixed to the cooling block 51 by a support member. Here, the substrate has a two-layer structure, but it may have three or more layers, and it is preferable that an electronic component with a larger calorific value be disposed closer to the cooling block 51. Further, when a metal upper lid is provided in the casing 41 of the control device 40, for example, the substrates 45a and 45b may be attached to the cooling block 51 via the upper lid and cooled.

  Inside the casing 41 of the control device 40, a temperature sensor 160 including a thermosensitive element such as a thermistor and a resistance type or capacitance type humidity sensor 170 are provided. The temperature sensor 160 is surface-mounted on the substrate 45a, and the humidity sensor 170 is surface-mounted on the substrate 46.

  In the present specification, a position near the cooling block 51 inside the housing 41 and when the refrigerant is supplied into the cooling block 51 is low in temperature, and particularly likely to cause dew condensation, is referred to as a “low temperature portion 181”. A position that is farther from the cooling block 51 than the low temperature part 181 and that is at a higher temperature than the low temperature part 181 will be referred to as a “high temperature part 182”. In the present embodiment, a temperature sensor 160 is provided in the low temperature part 181, and a humidity sensor 170 is provided in the high temperature part 182.

  When the humidity sensor 170 is provided in the low temperature part 181, the condensed water adheres to the humidity sensor 170, and there is a possibility that the humidity cannot be detected until the condensed water attached to the humidity sensor 170 evaporates. . In the present embodiment, since the humidity sensor 170 is provided in the high temperature part 182 where condensation is unlikely to occur, it is possible to prevent the condensed water from adhering to the humidity sensor 170.

  FIG. 3 is a functional block diagram showing the configuration of the turbo molecular pump 1. The turbo molecular pump 1 includes a main control unit 140, a power supply unit 151, a motor 101, a magnetic bearing 102, a three-way valve 150, a temperature sensor 160, a humidity sensor 170, a motor driving circuit 152, a magnetic bearing driving circuit 153, and a three-way valve driving circuit 154. It has.

  The power supply unit 151 includes an AC / DC conversion circuit, a DC / DC converter, and the like. The AC / DC conversion circuit converts AC power input to the control device 40 into DC power. The DC power converted by the AC / DC conversion circuit is supplied to the motor drive circuit 152, the magnetic bearing drive circuit 153, the three-way valve drive circuit 154, and the like. The direct current power converted by the AC / DC conversion circuit is converted into low voltage direct current power by the DC / DC converter and supplied to the main control unit 140.

  The main control unit 140 is configured to include an arithmetic processing unit having a CPU, a storage device such as ROM, RAM, and other peripheral circuits, and controls the operation of the turbo molecular pump 1. The main control unit 140 functionally includes a motor control unit 141, a magnetic bearing drive control unit 142, a temperature estimation unit 143, a condition determination unit 144, a valve control unit 145, and a dew condensation counter 149.

  The motor drive circuit 152 drives and controls the motor 101 based on the control signal input from the motor control unit 141. The magnetic bearing drive circuit 153 drives the magnetic bearing 102 based on the control signal input from the magnetic bearing drive control unit 142. The three-way valve drive circuit 154 drives the three-way valve 150 based on the control signal input from the valve control unit 145.

  The condensation counter 149 is a timer for measuring the duration of the state where condensation occurs and the duration of the state where condensation does not occur.

定数αは、主制御部１４０の記憶装置に予め記憶されている。 The temperature estimation unit 143 estimates the temperature of the high temperature unit 182 based on the temperature _TL of the low temperature unit 181 detected by the temperature sensor 160. Hereinafter, the temperature estimated by the temperature estimation unit 143 is referred to as “estimated temperature”. The temperature _{T L} of the low-temperature section 181, in order to estimate the temperature _{T H} of the high temperature portion 182, know the advance of the temperature _{T H} of the temperature _{T L} and the high temperature portion 182 of the low temperature portion 181 relationship. The relationship between the temperature T _H of the temperature T _L and the high temperature portion 182 of the low-temperature section 181 is different from the magnitude of the control unit 40, the arrangement of electronic components comprising a heating source. For example, the temperature _{T H} of the high-temperature portion 182, with respect to the temperature _{T L} of the low-temperature section 181, and was found to be a relation of about 1.7 times. In this case, the estimated temperature _{T H} of the high-temperature section 182, a constant alpha = 1.7 for estimating the temperature is represented by the formula (1).

The constant α is stored in advance in the storage device of the main control unit 140.

  The condition determination unit 144 determines which of the first cooling operation execution condition, the second cooling operation execution condition, and the cooling operation stop condition is satisfied.

The first cooling operation execution condition is satisfied when (Condition 1) or (Condition 2) is satisfied.
(Condition 1) The power switch of the stopped turbo molecular pump 1 is turned on (Condition 2) After the cooling operation stop condition is satisfied, the temperature in the casing 41 of the control device 40 is equal to or lower than the first temperature threshold T1. Yes, and no dew condensation has continued beyond the second time threshold t2.

The cooling operation stop condition is satisfied when (Condition 3) or (Condition 4) is satisfied.
(Condition 3) After the first cooling operation execution condition is established, the state in which condensation occurs is continued beyond the first time threshold t1, and the temperature in the casing 41 of the control device 40 is the first temperature. Being threshold value T1 or less (Condition 4) After the second cooling operation execution condition is satisfied, the temperature in the casing 41 of the control device 40 is not more than the second temperature threshold value T2.

The second cooling operation execution condition is satisfied when (condition 5) is satisfied.
(Condition 5) After the cooling operation stop condition is established, the temperature in the casing 41 of the control device 40 exceeds the first temperature threshold T1.

The condition determining unit 144, when the relative humidity _{R H} of the high temperature portion 182 detected by the humidity sensor 170 is higher than the humidity threshold R0 _(R H> R0), if there is a state where condensation has occurred judge. Condition determination unit 144 determines that the relative humidity R _H of the high temperature portion 182 detected by the humidity sensor 170 is when: humidity threshold R0 (R _H ≦ R0) is a state in which dew condensation does not occur.

  The first temperature threshold T1 is the upper limit temperature of the internal temperature at which the control device 40 operates stably, and is stored in advance in the storage device of the main control unit 140. The first temperature threshold T1 is set to a temperature lower than the temperature abnormality notification temperature set to be equal to or lower than the allowable temperature of the electronic component. The second temperature threshold T2 is a lower limit temperature of the internal temperature at which the control device 40 operates stably, and is stored in advance in the storage device of the main control unit 140. The second temperature threshold T2 is set to a temperature higher than the ambient environment temperature (for example, room temperature) as a temperature at which condensation does not easily occur.

  The first time threshold value t1 is set as a time until the temperature distribution in the casing 41 of the control device 40 is stabilized, and the second time threshold value t2 is generated immediately after the condensation is eliminated and the condensation is immediately generated by the supply of the refrigerant. This is the time set to prevent this. The first time threshold t1 and the second time threshold t2 are about one hour, for example, and are stored in advance in the storage device of the main control unit 140. The first time threshold t1 and the second time threshold t2 can be set to the same time or different times.

以下、湿度閾値Ｒ０について詳細に説明する。 Humidity threshold R0 can be set using the saturated vapor pressure P _H in the saturation vapor pressure P _L, and the high temperature portion 182 of the low temperature portion 181 is represented by the formula (2).

Hereinafter, the humidity threshold value R0 will be described in detail.

FIG. 4 is a diagram showing a saturated vapor pressure curve, in which the horizontal axis represents the temperature T and the vertical axis represents the saturated vapor pressure P of water vapor. The saturated vapor pressures P _L and P _H are obtained from a saturated vapor pressure curve. In the present embodiment, the approximate expression of the saturated vapor pressure curve is stored in advance in the storage device. Various functions f (T), which are approximate expressions of the saturated vapor pressure curve, have been proposed. For example, the function f (T) is expressed by the Tetens expression (3).

式（３）に高温部１８２の推定温度Ｔ_Ｈを代入することで、高温部１８２での飽和蒸気圧Ｐ_Ｈは式（５）により表される。

By substituting the temperature _TL of the low temperature part 181 into the formula (3), the saturated vapor pressure P _L at the low temperature part 181 is expressed by the formula (4).

By substituting the estimated temperature _{T H} of the high-temperature portion 182 in Equation (3), the saturated vapor pressure _{P H} of the high temperature portion 182 is represented by the formula (5).

ここで、Ｐ_Oは制御装置４０の筐体４１内の水蒸気圧である。つまり、低温部１８１での飽和蒸気圧Ｐ_Ｌに対して水蒸気圧Ｐ_Oが高い場合には、低温部１８１で結露が発生していると判定することができる。 Whether or not dew condensation is occurring in the low temperature part 181 can be determined by Equation (6).

Here, _PO is the water vapor pressure in the casing 41 of the control device 40. That is, when the water vapor pressure P _O is higher than the saturated vapor pressure P _L in the low temperature part 181, it can be determined that condensation occurs in the low temperature part 181.

Relative humidity _{R H} of the high temperature portion 182 is represented by equation (7).

このため、式（８）の右辺が、結露が発生している状態であるか否かを判定するための湿度閾値Ｒ０であり、湿度閾値Ｒ０は式（２）で表されるように制御装置４０の筐体４１内の温度変化にしたがって変化する。 Substituting equation (7) into equation (6) yields equation (8).

For this reason, the right side of Expression (8) is a humidity threshold value R0 for determining whether or not condensation is occurring, and the humidity threshold value R0 is represented by Expression (2). It changes according to the temperature change in 40 cases 41.

  The valve control unit 145 shown in FIG. 3 switches the three-way valve 150 to the supply position (that is, operates the cooling device 50) when the first cooling operation execution condition and the second cooling operation execution condition are satisfied, When the cooling operation stop condition is satisfied, the three-way valve 150 is switched to the bypass position (that is, the cooling device 50 is stopped).

  FIG. 5 is a flowchart showing the operation of the electromagnetic valve switching process by the main control unit 140 of the control device 40 according to the first embodiment, and FIG. 6 is a flowchart showing the operation of the dew condensation state determination process. When the power switch of the turbo molecular pump 1 is turned on, a valve control program is executed. After initial setting (not shown), the processing after step S100 is repeatedly executed every predetermined control cycle. In the initial setting, the main control unit 140 determines that the first cooling operation execution condition is satisfied, and outputs a control signal for switching the three-way valve 150 to the supply position. In the initial setting, the condensation counter 149 is reset.

  As shown in FIG. 5, in step S100, the main control unit 140 determines whether or not condensation is occurring. Step S100 is repeated until an affirmative determination is made, and when an affirmative determination is made, the process proceeds to step S105. It is determined according to the process shown in FIG. 6 whether or not condensation is occurring.

As shown in FIG. 6, in step S10, the main control unit 140 obtains the relative humidity _{R H} of the temperature _{T L} and the high temperature portion 182 of the low-temperature section 181 is information from the temperature sensor 160 and the humidity sensor 170, step Proceed to S20.

In step S20, the main control unit 140, based on the temperature _{T L} of the low-temperature section 181 acquired in step S10, calculates the estimated temperature _{T H} of the high temperature portion 182, the process proceeds to step S30.

In step S30, the main control unit 140, based on the temperature _{T L} of the low-temperature section 181 acquired in step S10, calculates the saturated vapor pressure _{P L} of the low-temperature portion 181, the process proceeds to step S40.

In step S40, the main control unit 140, based on the estimated temperature _{T H} of the high temperature portion 182 obtained in step S20, it calculates the saturated vapor pressure _{P H} of the high temperature portion 182, the process proceeds to step S50.

In step S50, the main control unit 140, based on the saturated vapor pressure _{P L} of the low temperature portion 181 obtained in step S30, to the saturated vapor pressure _{P H} of the high temperature portion 182 obtained in step S40, the humidity threshold R0 Is calculated and the process proceeds to step S60.

In step S60, the main control unit 140, the relative humidity _{R H} of the high temperature portion 182 acquired in step S10 is equal to or higher than or humidity threshold R0 obtained in step S50. If an affirmative determination is made in step 60, the process proceeds to step S70, and if a negative determination is made, the process proceeds to step S80.

  In step S70, the main control unit 140 determines that condensation is occurring, and sets a flag indicating that condensation is occurring. In step S80, the main control unit 140 determines that no condensation has occurred, and sets a flag indicating that no condensation has occurred.

  As shown in FIG. 5, if it is determined in step S100 that condensation has occurred, in step S105, the main control unit 140 adds the time of the condensation counter 149 and proceeds to step S110.

  In step S110, the main control unit 140 determines whether the time t counted by the dew condensation counter 149 has exceeded the first time threshold t1. If an affirmative determination is made in step S110, the process proceeds to step S115, and if a negative determination is made, the process returns to step S100.

  In step S115, the main control unit 140 resets the condensation counter 149, that is, sets the accumulated time t to 0, and proceeds to step S120.

In step S120, the main control unit 140 acquires the temperature _TL of the low temperature unit 181 that is information from the temperature sensor 160 as the temperature in the housing 41, and proceeds to step S130. In step S130, the main control unit 140 determines whether or not the temperature _TL is equal to or lower than the first temperature threshold T1. If an affirmative determination is made in step S130, the process proceeds to step S140, and if a negative determination is made, the process proceeds to step S180.

  In step S140, the main control unit 140 outputs a control signal for switching the three-way valve 150 to the bypass position, and proceeds to step S151.

  In step S151, the main control unit 140 determines whether or not condensation is occurring, as in step S100 (steps S10 to S80). If an affirmative determination is made in step S151, the process returns to step S120, and if a negative determination is made, the process proceeds to step S156.

  In step S156, the main control unit 140 accumulates the time of the condensation counter 149 and proceeds to step S161.

  In step S161, the main control unit 140 determines whether or not the time t counted by the dew condensation counter 149 exceeds the second time threshold t2. If a positive determination is made in step S161, the process proceeds to step S166, and if a negative determination is made, the process returns to step S120.

  In step S166, the main control unit 140 resets the condensation counter 149, that is, sets the accumulated time t to 0, and proceeds to step S171. In step S171, the main control unit 140 outputs a control signal for switching the three-way valve 150 to the supply position, and returns to step S100.

If it is determined in step S130 that the temperature _TL is higher than the first temperature threshold value T1, the process proceeds to step S180. In step S180, the main control unit 140 generates a control signal for switching the three-way valve 150 to the supply position. Output, and proceed to step S185.

In step S185, the main control unit 140 acquires the temperature _TL of the low temperature unit 181 that is information from the temperature sensor 160 as the temperature in the housing 41, and proceeds to step S190. In step S190, the main control unit 140 determines whether or not the temperature _TL is equal to or lower than the second temperature threshold T2. If an affirmative determination is made in step S190, the process proceeds to step S140, and if a negative determination is made, the process returns to step S180.

  The operation of the first embodiment is summarized as follows. When the user turns on the power switch of the turbo molecular pump 1, the turbo molecular pump 1 is activated. Since the first cooling operation execution condition is satisfied, the three-way valve 150 is switched to the supply position.

  When the drive switch for commanding the driving of the motor of the turbo molecular pump 1 is turned off, the vicinity of the cooling block 51 in the control device 40 is in a low temperature state. Condensation occurs in the low temperature part 181 in the control device 40 (Yes in step S100), the state continues for the first time threshold t1 (for example, 1 hour) (Yes in step S110), and the housing 41 of the control device 40 If the internal temperature is equal to or lower than the first temperature threshold T1 (Yes in step S130), the cooling operation stop condition is satisfied, so the three-way valve 150 is switched to the bypass position, and the supply of the refrigerant to the cooling block 51 is shut off. (Step S140).

  When the supply of the refrigerant to the cooling block 51 is interrupted, that is, when the cooling device 50 is stopped, the motor rotates, the temperature of the control device 40 gradually increases. When the temperature in the casing 41 of the control device 40 exceeds the first temperature threshold T1 (No in step S130), the second cooling operation execution condition is satisfied, so the three-way valve 150 is switched to the supply position, and the cooling block 51 The refrigerant is supplied to (Step S180).

  When the refrigerant is supplied to the cooling block 51, the temperature of the control device 40 gradually decreases. If the temperature in the control device 40 is higher than the second temperature threshold T2, it is difficult for condensation to occur, so the supply of refrigerant is continued (No in step S190).

  When the motor drive switch is turned off and the rotation of the motor 101 is stopped, and the temperature of the control device 40 becomes equal to or lower than the second temperature threshold T2 (Yes in step S190), the cooling operation stop condition is satisfied. The valve 150 is switched to the bypass position, and the supply of the refrigerant to the cooling block 51 is shut off (step S140). That is, once the cooling operation is executed due to the temperature rise, the cooling operation is executed until the temperature in the control device 40 becomes equal to or lower than the second temperature threshold T2 regardless of whether or not the condensation state is present. Keep doing.

  This is a case where the temperature rise in the state where the supply of the refrigerant to the cooling block 51 is cut off is moderate or constant, and the temperature in the casing 41 of the control device 40 is equal to or lower than the first temperature threshold T1 (step) If the state in which condensation has not occurred continues for the second time threshold t2 (for example, 1 hour) (Yes in step S161), the first cooling operation execution condition is satisfied, and the three-way valve 150 is supplied. The position is switched to and the refrigerant is supplied to the cooling block 51 (step S171).

  As described above, according to the present embodiment, since the execution and stop of the cooling operation are controlled based on the state of occurrence of condensation and the temperature in the housing 41, the occurrence of condensation is suppressed and caused by condensation. The temperature rise of the control device 40 can be effectively suppressed while preventing the occurrence of malfunctions.

According to the first embodiment described above, the following operational effects are obtained.
(1) based on the temperature _{T L} of the low-temperature portion 181 detected by the temperature sensor 160, and estimates the temperature _{T H} of the high temperature portion 182, and the estimated temperature _{T H} of the estimated high temperature portion 182, detected by the temperature sensor 160 comprising a temperature T _L of the low-temperature portion 181 which is, on the basis of the relative humidity R _H of the high temperature portion 182 detected by the humidity sensor 170, the main control unit 140 for controlling the execution and stop of the cooling operation of the cooling device 50 I did it.

  Since the detection information necessary for controlling the cooling operation is limited to two, the probability of false detection is reduced and the condensation state is reduced compared to the case where three or more pieces of information are detected to control the cooling operation. The reliability of the determination can be improved.

(2) Since the number of sensors can be reduced as compared with the technique described in Patent Document 1 (hereinafter referred to as conventional technique), cost reduction and weight reduction can be achieved.

(3) The temperature sensor 160 is surface-mounted on the metal substrate 45a connected to the cooling block 51 forming the cooling channel so as to be capable of conducting heat. Thereby, compared with the case where a temperature sensor is directly fixed to the cooling block 51, size reduction and cost reduction can be achieved. When the temperature sensor is directly attached to the cooling block 51, a fixture for fixing screws or the like and a dedicated harness for connecting the temperature sensor and the substrate are required. On the other hand, in the present embodiment, since the temperature sensor 160 including a thermal element such as a thermistor is surface-mounted on the substrate 45a, a fixture or a dedicated harness is not necessary.

(4) As a condition for determining that the cooling operation stop condition is satisfied, it is adopted that the state where condensation occurs is continued for a predetermined time t1. Here, the predetermined time is set as a time indicating that the temperature distribution in the casing 41 of the control device 40 is stable. Thereby, since it can be determined that condensation has occurred while the temperature distribution in the housing 41 is stable, it is possible to prevent erroneous determination of the condensation state in an unstable state.

(5) The refrigerant is supplied when the state in which no condensation occurs has continued for a predetermined time t2. Here, the predetermined time t2 is set as a time for preventing the condensation from occurring immediately after the condensation is eliminated due to the supply of the refrigerant. If it is not determined whether or not the state where condensation has not occurred continues for the predetermined time t2, the three-way valve 150 is immediately switched to the supply position when it is determined that condensation has not occurred (step S171). Condensation may occur immediately when the low temperature part 181 is cooled. On the other hand, in the present embodiment, since the refrigerant is supplied when the state in which no condensation has occurred continues for the predetermined time t2, the condensation is immediately generated by the supply of the refrigerant after the condensation is eliminated. Is prevented, and a stable state in which condensation does not occur can be maintained.

(6) When the operation of the cooling device 50 is stopped, the cooling operation is executed when the temperature in the housing 41 of the control device 40 becomes higher than the first temperature threshold T1 (No in step S130). . Thereby, the temperature rise of the control device 40 can be suppressed, and the operation of the notification device such as an alarm for notifying the temperature abnormality caused by the temperature rise and the stop of the device can be prevented.

(7) When the cooling operation is being performed, regardless of whether or not it is in the dew condensation state until the temperature in the housing 41 becomes lower than the second temperature threshold T2 that is lower than the first temperature threshold T1. The cooling operation is executed (No in step S190), and the cooling operation is stopped when the temperature in the housing 41 becomes lower than the second temperature threshold T2 (Yes in step S190). The second temperature threshold T2 is set to be higher than the ambient environment temperature. For this reason, the cooling operation is continued even when temperature information or relative humidity information that is determined to be a state in which condensation has occurred is detected when the temperature is higher than the second temperature threshold T2. Therefore, it is possible to prevent the cooling operation from being stopped due to erroneous detection of temperature information and relative humidity information.

-Second Embodiment-
With reference to FIG. 7 and FIG. 8, the turbo-molecular pump 1 which concerns on 2nd Embodiment is demonstrated. The turbo molecular pump 1 according to the second embodiment has the same configuration as that of the first embodiment. In the figure, the same reference numerals are assigned to the same or corresponding parts as those in the first embodiment, and the differences will be mainly described. FIG. 7 is a diagram similar to FIG. 2, and is a schematic diagram showing positions of the temperature sensor 160 and the humidity sensor 170 in the control device 40 according to the second embodiment.

In the first embodiment, the example in which the temperature sensor 160 is arranged in the low temperature part 181 has been described (see FIG. 2). In contrast, in the second embodiment, is arranged a temperature sensor 160 to a high temperature portion 182, the temperature _{T H} of the high-temperature portion 182 is detected by the temperature sensor 160.

ここで、αは、温度を推定するための定数であり、本実施の形態では、α＝１．７である。定数αは、主制御部１４０の記憶装置に予め記憶されている。 In the second embodiment, the temperature estimating unit 143 shown in FIG. 3, based on the temperature _{T H} of the high temperature portion 182 detected by the temperature sensor 160, and estimates the temperature _{T L} of the low temperature portion 181. The estimated temperature _TL of the low temperature part 181 is expressed by Expression (9) obtained by modifying Expression (1).

Here, α is a constant for estimating the temperature, and α = 1.7 in the present embodiment. The constant α is stored in advance in the storage device of the main control unit 140.

  FIG. 8 is a flowchart showing the operation of the dew condensation state determination process according to the second embodiment, in which steps S10B and S20B are added instead of steps S10 and S20 in the flowchart of FIG. .

As shown in FIG. 8, in the second embodiment, in step 10B, the main control unit 140, the relative temperatures _{T H} and the high temperature portion 182 of the high temperature portion 182 which is information from the temperature sensor 160 and humidity sensor 170 The humidity _RH is acquired, and the process proceeds to step S20B.

In step S20B, the main control unit 140, based on the temperature _{T H} of the high temperature portion 182 acquired in step S10B, calculates the estimated temperature _{T L} of the low-temperature portion 181, the process proceeds to step S30.

Thus, in the second embodiment, the temperature T _H of the high temperature portion 182 detected by the temperature sensor 160, and the relative humidity R _H of the high temperature portion 182 detected by the humidity sensor 170, the estimated low temperature part Based on the estimated temperature _{TL of} 181, the dew condensation state is determined, and the refrigerant flow in the cooling flow path is controlled.

  According to the second embodiment, the same operational effects as the first embodiment can be obtained.

-Third embodiment-
With reference to FIG. 9, the turbo-molecular pump 1 which concerns on 3rd Embodiment is demonstrated. The turbo molecular pump 1 according to the third embodiment has a configuration similar to that of the first embodiment. Hereinafter, differences from the first embodiment will be described. FIG. 9 is a flowchart showing the operation of the solenoid valve switching process according to the third embodiment.

  In the first embodiment, the switching control of the three-way valve 150 is executed in consideration of the temperature in the housing 41 of the control device 40. On the other hand, in the third embodiment, switching control of the three-way valve 150 is executed based on whether or not condensation occurs regardless of the temperature in the housing 41 of the control device 40. This will be specifically described below.

  The condition determination unit 144 illustrated in FIG. 3 determines which of the cooling operation execution condition and the cooling operation stop condition is satisfied.

The cooling operation execution condition is satisfied when (Condition 1C) or (Condition 2C) is satisfied.
(Condition 1C) The power switch of the turbo-molecular pump 1 was turned on during the stop (Condition 2C) After the cooling operation stop condition was established, the state where no dew condensation occurred continued beyond the second time threshold t2. Was it

The cooling operation stop condition is satisfied when (Condition 3C) is satisfied (Condition 3C). After the cooling operation execution condition is satisfied, the state in which condensation occurs is continued beyond the first time threshold t1. about

  The processes in steps S200, S205, S210, and 215 shown in FIG. 9 are the same as the processes in steps S100, S105, S110, and S115 shown in FIG. Further, the processes in steps S240, S251, S256, S261, S266, and S271 shown in FIG. 9 are the same as the processes in steps S140, S151, S156, S161, S166, and S171 shown in FIG. That is, the flowchart shown in FIG. 9 is obtained by omitting steps S120, S130, S180, S185, and S190 in the flowchart shown in FIG.

  When the process of step S215 is completed, the process proceeds to step S240, and the main control unit 140 executes control for switching the three-way valve 150 to the detour position as in step S140, and the process proceeds to step S251.

  In step S251, the main control unit 140 determines whether or not condensation has occurred. Step S251 is repeated until a negative determination is made, and when a negative determination is made, the process proceeds to step S256. It is determined according to the process shown in FIG. 6 whether or not condensation is occurring.

  If it is determined in step S251 that no condensation has occurred, in step S256, the main control unit 140 accumulates the time of the condensation counter 149 and proceeds to step S261.

  In step S261, the main control unit 140 determines whether the time t counted by the dew condensation counter 149 has exceeded the second time threshold t2. If an affirmative determination is made in step S261, the process proceeds to step S266, and if a negative determination is made, the process returns to step S251.

  In step S266, the main control unit 140 resets the condensation counter 149, that is, sets the accumulated time t to 0, and proceeds to step S271. In step S271, the main control unit 140 outputs a control signal for switching the three-way valve 150 to the supply position, as in step S171, and proceeds to step S200.

  According to such 3rd Embodiment, there exists an effect similar to (1)-(5) demonstrated in 1st Embodiment.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(Modification 1)
In the above-described embodiment, the example in which the constant α is used as the value for estimating the temperature has been described, but the present invention is not limited to this.

(Modification 1-1)
For example, a constant suitable for the operation state may be selected from a plurality of constants based on the operation state of the turbo molecular pump 1. When the refrigerant is supplied into the cooling block 51, that is, when the cooling operation is being performed, and when the supply of the refrigerant into the cooling block 51 is interrupted, that is, when the cooling operation is stopped. Then, the relationship between the temperature of the low temperature part 181 and the temperature of the high temperature part 182 is different. For this reason, it is preferable to examine the relationship between the temperature of the low temperature part 181 and the temperature of the high temperature part 182 in advance at each switching position of the three-way valve 150.

  The difference between the temperature of the low temperature part 181 and the temperature of the high temperature part 182 is larger when the cooling operation is performed than when the cooling operation is stopped. For example, it can be seen that the temperature of the high temperature part 182 in the operation state in which the refrigerant is supplied into the cooling block 51 is about 1.7 times the temperature of the low temperature part 181. It is assumed that the temperature of the high temperature part 182 in the operation state in which the supply of the refrigerant to is cut off is approximately 1.3 times the temperature of the low temperature part 181.

  In this case, the first constant α1 = 1.7 and the second constant α2 = 1.3 are stored in the storage device of the main control unit 140 in advance. When the three-way valve 150 is switched to the supply position, the main control unit 140 selects the first constant α1 as the constant α for estimating the temperature (α = α1), and uses the equations (1) and (9). Estimate temperature. When the three-way valve 150 is switched to the bypass position, the main control unit 140 selects the second constant α2 as the constant α for estimating the temperature (α = α2), and uses the equations (1) and (9). Estimate temperature.

According to such (Modification 1-1), in addition to the same functions and effects as those of the first embodiment, the following functions and effects are achieved.
(8) When the cooling operation is being performed, the main control unit 140 compares the temperature T _H (or T _L ) detected by the temperature sensor 160 and the estimated temperature as compared to when the cooling operation is stopped. The estimated temperature is estimated so that the difference from T _L (or T _H ) becomes large. Thereby, since the estimation accuracy of temperature can be improved, the estimation accuracy of a dew condensation state can be improved.

(Modification 1-2)
When the load of the motor 101 that drives the pump body 10 of the turbo molecular pump 1 is higher than the predetermined load, the estimated temperature is detected by the temperature sensor 160 compared to the case where the load of the motor 101 is lower than the predetermined load. The estimated temperature may be estimated so that the difference from the temperature becomes large. For example, it is detected whether the motor is rotationally driven or stopped, and when the motor is rotationally driven, the temperature detected by the temperature sensor 160 compared to when it is stopped. The estimated temperature can be estimated so that the difference between the estimated temperature and the estimated temperature becomes large. According to such (Modification 1-2), similarly to (Modification 1-1), it is possible to estimate the temperature suitable for the operation state, so that it is possible to improve the estimation accuracy of the dew condensation state. it can.

(Modification 1-3)
The value α for estimating the temperature may be a variable instead of a constant. For example, a function α (T) corresponding to the temperature detected by the temperature sensor 160 may be used as a value for estimating the temperature. According to such (Modification 1-3), similarly to (Modification 1-1), it is possible to estimate the temperature suitable for the operating state, so that it is possible to improve the estimation accuracy of the condensation state. it can.

(Modification 1-4)
The power consumption of the motor is calculated, and the value α for estimating the temperature may be set so that the difference between the temperature detected by the temperature sensor 160 and the estimated temperature increases as the power consumption increases. According to such (Modification 1-4), similarly to (Modification 1-1), it is possible to estimate the temperature suitable for the operation state, so that it is possible to improve the estimation accuracy of the condensation state. it can.

(Modification 2)
In the first embodiment, an example in which the temperature detected by the low temperature part 181 is multiplied by a constant α to estimate the temperature of the high temperature part 182 will be described. In the second embodiment, the temperature detected by the high temperature part 182 is described. The example in which the constant α is divided by the calculated temperature to estimate the temperature of the low temperature part 181 has been described, but the present invention is not limited to this. Instead of multiplying or dividing by the constant α, the constant β is added to the temperature detected by the low temperature portion 181 to estimate the temperature of the high temperature portion 182, or the temperature detected by the high temperature portion 182 is constant β May be subtracted to estimate the temperature of the low temperature part 181. It is preferable to employ a method capable of estimating the temperature with higher accuracy in accordance with the relationship between the temperature of the low temperature part 181 and the temperature of the high temperature part 182 that change depending on the shape and size of the control device 40, the arrangement of electronic components, and the like.

(Modification 3)
In the above-described embodiment, the example in which the supply / detour of the refrigerant to the cooling block 51 is switched by the three-way valve 150 has been described, but the present invention is not limited to this. Instead of the three-way valve 150, an electromagnetic on-off valve that can switch the supply / cutoff of the refrigerant to the cooling block 51 may be adopted.

(Modification 4)
In the above-described embodiment, the supply of the refrigerant to the cooling block 51 is interrupted, that is, the supply flow of the refrigerant to the cooling block 51 is set to 0 as the stop of the cooling operation, but the present invention is limited to this. Not. Compared to when the cooling operation is being performed, the flow rate of the refrigerant is reduced, and the supply flow rate of the refrigerant is such that the refrigerant can be returned to a state where condensation does not occur. Also means that the cooling operation is stopped.

(Modification 5)
In the above-described embodiment, the configuration in which the control device 40 is disposed below the pump body 10 has been described, but the present invention is not limited to this. For example, the control device 40 may be disposed on the side of the lower casing 30 of the pump body 10. Further, the present invention is not limited to the case where the pump body 10 and the control device 40 are combined to form an integrated structure. In this case, the cooling device 50 is provided in each of the control device 40 and the pump body 10.

(Modification 6)
In the embodiment described above, in step S130, it is determined whether or not the temperature _TL of the low temperature part 181 is equal to or lower than the first temperature threshold T1 as the temperature in the housing 41. In step S190, the temperature of the low temperature part 181 is determined. Although the example which determines whether _TL is below 2nd temperature threshold value T2 was demonstrated, this invention is not limited to this. Instead of the temperature _{T L} of the low-temperature section 181 may compare the temperature _{T H} of the high-temperature portion 182 with a predetermined threshold. Instead of the temperature _{T L} of the low-temperature section 181 may compare the average value of the temperature _{T H} of the temperature _{T L} and the high temperature portion 182 of the low temperature portion 181 with a predetermined threshold.

(Modification 7)
In embodiment mentioned above, it is not limited to using water as a refrigerant | coolant, A various cooling fluid can be used as a refrigerant | coolant.

(Modification 8)
In the above-described embodiment, the cooling device 50 that flows the refrigerant through the cooling pipe 52 has been described as an example, but the present invention is not limited to this. For example, a cooling device that cools the cooling block 51 with cooling air generated by a cooling fan may be employed. By controlling the flow rate of the cooling air, it is possible to cool the control device 40 while suppressing the occurrence of condensation.

(Modification 9)
In the above-described embodiment, the example in which the turbo molecular pump is employed as the vacuum pump has been described. However, the present invention is not limited to this, and the present invention can be applied to various vacuum pumps. For example, the present invention can also be applied to a vacuum pump having only a drag pump such as a Ziegburn pump or a Holweck pump.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

DESCRIPTION OF SYMBOLS 1 Turbo molecular pump, 10 Pump main body, 11 Inlet flange, 20 Upper casing, 21 Flange, 30 Lower casing, 32 Flange, 40 Control apparatus, 41 Case, 45a Substrate, 46 Substrate, 50 Cooling device, 51 Cooling block, 52 cooling pipe, 52b bypass flow path, 52i refrigerant inlet, 52o refrigerant outlet, 101 motor, 102 magnetic bearing, 140 main controller, 141 motor controller, 142 magnetic bearing drive controller, 143 temperature estimator, 144 conditions Determination unit, 145 valve control unit, 149 dew counter, 150 three-way valve, 151 power supply unit, 152 motor drive circuit, 153 magnetic bearing drive circuit, 154 three-way valve drive circuit, 160 temperature sensor, 170 humidity sensor, 181 low temperature unit, 182 High temperature part

Claims (7)

A pump controller for controlling the vacuum pump;
A cooling device for cooling the pump control unit;
A housing that houses the pump controller;
A temperature sensor for detecting a temperature at one of a first position in the housing and a second position at a higher temperature than the first position;
A humidity sensor for detecting humidity at the second position in the housing;
A temperature estimation unit that estimates the temperature at the other of the first position and the second position based on the temperature detected by the temperature sensor;
Cooling control for controlling execution and stop of the cooling operation by the cooling device based on the estimated temperature estimated by the temperature estimation unit, the temperature detected by the temperature sensor, and the humidity detected by the humidity sensor And a vacuum pump control device. In the vacuum pump control device according to claim 1,
The temperature estimation unit estimates the temperature of the second position by multiplying or adding a constant to the temperature of the first position detected by the temperature sensor, or the temperature detected by the temperature sensor A controller for a vacuum pump, which estimates the temperature at the first position by dividing or subtracting a constant from the temperature at the second position. The control device for a vacuum pump according to claim 1 or 2,
The cooling controller is
When the humidity is higher than the predetermined humidity, it is determined that it is in a dew condensation state.
An operation control unit that stops the cooling operation when the state determined to be the dew condensation state is continued for a predetermined time;
The predetermined time is set as a time indicating that the temperature distribution in the housing is stable,
The operation controller is
When the cooling operation is stopped, the vacuum pump control device causes the cooling operation to be executed when the temperature in the housing becomes higher than the first temperature. The control device for a vacuum pump according to claim 3,
The operation controller is
When the cooling operation is being performed, the cooling operation is performed regardless of whether or not the dew condensation state is present until the temperature inside the casing becomes lower than the second temperature lower than the first temperature. ,
The control apparatus for vacuum pumps that stops the cooling operation when the temperature in the housing becomes lower than the second temperature. In the vacuum pump control device according to any one of claims 1 to 4,
When the cooling operation is being performed, the temperature estimation unit is configured such that the difference between the temperature detected by the temperature sensor and the estimated temperature is greater than when the cooling operation is stopped. And a controller for a vacuum pump for estimating the estimated temperature. In the vacuum pump control device according to any one of claims 1 to 5,
When the load of the motor that drives the vacuum pump is higher than a predetermined load, the temperature estimation unit may detect the temperature detected by the temperature sensor as compared with the case where the load of the motor is lower than the predetermined load. A controller for a vacuum pump that estimates the estimated temperature such that a difference from the estimated temperature is large. In the vacuum pump control device according to any one of claims 1 to 6,
The cooling device includes a flow path forming body that forms a cooling flow path for circulating a coolant for cooling the pump control unit,
A metal substrate is connected to the flow path forming body so as to be thermally conductive,
The temperature sensor is a vacuum pump control device that is surface-mounted on the substrate at the first position.

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