Vacuum pump, decontamination device and exhaust gas treatment system

Abstract

Provided is a vacuum pump that can achieve energy saving when exhaust gas is decontaminated. A vacuum pump (2) that sucks and discharges exhaust gas is characterized by comprising: a motor (MT) as a drive source; and a first controller (29) that controls driving of the motor; the first controller monitors a state of the motor, and outputs a specific signal (process signal) to the outside in a case where the state of the motor is a specific state other than at the time of start and at the time of stop.

Description

Technical Field

[0001] This invention relates to vacuum pumps, purifying devices, and exhaust gas treatment systems. Background Technology

[0002] Since the exhaust gases emitted from semiconductor manufacturing equipment and the like contain harmful components, there is a need for a decontamination device to render the exhaust gases harmless.

[0003] For example, Patent Document 1 describes controlling the operation of a pest control device based on the output power of an inverter that drives a vacuum pump motor. According to Patent Document 1, energy saving can be achieved by stopping / starting the operation of the pest control device based on whether the inverter's output is higher or lower than a threshold.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent document 1: Japanese Patent Application Publication No. 2015-194150. Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, if the operation of the pest control device is controlled solely by the output of the vacuum pump's inverter, as in Patent Document 1, the device's operation will stop and restart depending on changes in power consumption, such as during motor acceleration or deceleration. Therefore, Patent Document 1 has room for improvement from an energy-saving perspective.

[0009] The present invention was made in view of the above-mentioned actual situation, and its purpose is to provide a vacuum pump, a purifying device and a purifying gas treatment system that can achieve energy saving when purifying exhaust gas.

[0010] Methods used to solve problems

[0011] To achieve the above objectives, one aspect of the present invention is a vacuum pump that draws in and discharges exhaust gas, characterized in that it comprises: a motor as a drive source; and a first controller that controls the drive of the motor; the first controller monitors the state of the motor and outputs a specific signal to the outside when the state of the motor is a specific state other than when it is starting or when it is stopped.

[0012] Furthermore, in the above structure, it is preferable that the aforementioned specific state is a state in which the aforementioned motor is operating normally and the current of the aforementioned motor exceeds a predetermined threshold.

[0013] Furthermore, in the above structure, it is preferable that the first controller outputs the specific signal to the external source during the period when the motor is operating normally and the current of the motor exceeds the predetermined threshold, and continues to output the specific signal to the external source from the time the current of the motor falls below the predetermined threshold until a predetermined time has elapsed.

[0014] Furthermore, in the above structure, it is preferable that the aforementioned predetermined time is set to be a time exceeding the time until the aforementioned exhaust gas discharged from the aforementioned vacuum pump reaches the pest control device disposed downstream of the aforementioned vacuum pump.

[0015] Furthermore, in the above structure, it is preferable that the aforementioned external component is a second controller that controls the operation of the aforementioned pest control device.

[0016] Furthermore, in the above structure, it is preferable that the first controller prohibits the output of the specific signal to the external source from the moment the motor starts and begins normal operation until a specific time has elapsed.

[0017] To achieve the above objectives, another aspect of the present invention is a pest control device, which is installed in a system that collects exhaust gases discharged from multiple vacuum pumps to control the exhaust gases discharged from the multiple vacuum pumps. The device is characterized by comprising: a combustion furnace for burning the exhaust gases; a solenoid valve for opening and closing to supply fuel gas to the combustion furnace; and a second controller for controlling the opening and closing of the solenoid valve; wherein the second controller controls the opening degree of the solenoid valve based on the sum of signals input from the multiple vacuum pumps.

[0018] To achieve the above objectives, another aspect of the present invention is a pest control device, which is installed in a system that collects exhaust gases discharged from multiple vacuum pumps to control the exhaust gases discharged from the multiple vacuum pumps. The device is characterized by comprising: a combustion furnace for burning the exhaust gases; a solenoid valve for opening and closing to supply fuel gas to the combustion furnace; and a second controller for controlling the opening and closing of the solenoid valve. The second controller controls the opening degree of the solenoid valve based on the total value of the motor current input from the multiple vacuum pumps.

[0019] To achieve the above objectives, another aspect of the present invention is an exhaust gas treatment system comprising a vacuum pump for drawing in and discharging exhaust gas, and a decontamination device for decontaminating the exhaust gas discharged from the vacuum pump. The vacuum pump comprises: a motor as a drive source; and a first controller for controlling the drive of the motor; the decontamination device comprises: a combustion furnace for burning the exhaust gas; a solenoid valve for opening and closing to supply fuel gas to the combustion furnace; and a second controller for controlling the opening and closing of the solenoid valve; the first controller monitors the state of the motor and outputs a specific signal to the second controller when the motor is in a specific state other than when it is starting or stopping; the second controller controls the opening and closing of the solenoid valve based on the specific signal from the first controller.

[0020] Invention Effects

[0021] According to the present invention, energy conservation can be achieved when removing pollutants from exhaust gases. Furthermore, issues, structures, and effects other than those described above will become clear from the following description of the embodiments. Attached Figure Description

[0022] Figure 1 This is an overall structural diagram of the exhaust gas treatment system according to the first embodiment of the present invention.

[0023] Figure 2 This is a cross-sectional view showing the internal structure of a turbomolecular pump.

[0024] Figure 3 This is a structural diagram showing the detailed features of the pest control device.

[0025] Figure 4 This is a flowchart showing the sequence of control processing by the TMP controller.

[0026] Figure 5 It is a time graph that shows the changes in motor speed, motor current, and process signal output from the start of rotation of the turbomolecular pump motor to its stop over time.

[0027] Figure 6 This is an overall structural diagram of the exhaust gas treatment system according to the second embodiment of the present invention.

[0028] Figure 7 It is a time graph showing the changes in the operating status of the pest control device.

[0029] Figure 8 It is a time graph showing the changes in the operating status of the pest control device (variant example). Detailed Implementation

[0030] The following is a reference to the appendix. Figure 1 The embodiments of the present invention will be described below.

[0031] (First Embodiment)

[0032] Figure 1 This is an overall structural diagram of the exhaust gas treatment system according to the first embodiment of the present invention. Figure 1 The exhaust gas treatment system shown is used, for example, to render harmless the exhaust gas (process gas, cleaning gas) discharged from the process chamber 1 of a semiconductor manufacturing apparatus, a flat panel display manufacturing apparatus, a solar panel manufacturing apparatus, etc.

[0033] Within process chamber 1, CVD (Chemical Vapor Deposition) processes, etching processes, and other processes (hereinafter referred to as process processing) are performed to form films using chemical vapor phase reactions. Various gases are used in process chamber 1. Examples of these gases include silane (SiH4), NH3, and H2, which are used as film-forming materials for semiconductor devices, liquid crystal panels, and solar cells. Inert gases such as NF3, CF4, C2F6, SF6, CHF3, and CF6, as well as nitrogen (N2), are used as cleaning gases in process chambers such as those used for plasma cleaning.

[0034] In process chamber 1, a turbomolecular pump (TMP) 2, serving as an example of a vacuum pump, is connected for vacuum evacuation to remove the harmful exhaust gas. A dry pump (DRP) 3 is connected in series with the turbomolecular pump 2 downstream of it. Furthermore, when removing the exhaust gas from process chamber 1, the dry pump 3 is first used to create a vacuum to a certain extent at the start of operation, and then the turbomolecular pump 2 is used to create a vacuum to the required low pressure. Alternatively, a rotary pump can be used instead of the dry pump 3, and depending on the specifications of the exhaust gas treatment system, the dry pump 3 itself can be omitted.

[0035] Harmful exhaust gases discharged from process chamber 1 via turbomolecular pump 2 and dry pump 3 are combusted and decomposed by the purifying device 4, then electrostatically collected by the electrostatic precipitator 5, and finally reach the central scrubber 6. At this point, the exhaust gases are slightly depressurized by the central scrubber 6 and guided into the purifying device 4 and the electrostatic precipitator 5. Alternatively, the purifying device 4 and the electrostatic precipitator 5 may be configured as a single unit.

[0036] Next, among the devices constituting the exhaust gas treatment system, the turbomolecular pump 2 and the purifying device 4 will be described in detail. The structures of the electrostatic precipitator 5 and the central scrubber 6 are well-known, so detailed descriptions are omitted.

[0037] Figure 2 This is a cross-sectional view showing the internal structure of the turbomolecular pump 2. (Example) Figure 2 As shown, the turbomolecular pump 2 is, for example, a composite pump that has a turbomolecular pump mechanism Pt and a grooved pump mechanism Ps as a gas discharge mechanism. A stator column 23 is erected inside the outer casing 21. A rotating body 24 is provided on the outside of the stator column 23. In addition, various electrical components are built into the inside of the stator column 23, such as a magnetic bearing MB that serves as a support mechanism for supporting the rotating body 24 in its radial and axial directions, and a motor MT that serves as a drive source (drive mechanism) for rotating the rotating body 24.

[0038] A rotating shaft 25 is provided inside the rotating body 24. The rotating shaft 25 is located inside the stator column 23 and is integrally connected to the rotating body 24. Furthermore, by supporting the rotating shaft 25 with a magnetic bearing MB, the rotating body 24 is rotatably supported at predetermined positions in its axial and radial directions. Moreover, by rotating the rotating shaft 25 with a motor MT, the rotating body 24 is driven to rotate about its rotation center (specifically, about the center of the rotating shaft 25). A plurality of moving blades 26 are provided on the outer peripheral surface of the rotating body 24, and a plurality of fixed blades 27 are provided on the inner peripheral surface of the outer casing 21 at positions corresponding to the plurality of moving blades 26.

[0039] In this way, the turbomolecular pump 2, with the help of the rotation of the rotating body 24, draws in the above-mentioned exhaust gas from the intake port 21A and exhausts the drawn-in exhaust gas to the outside from the exhaust port 21B.

[0040] The aforementioned motor MT is driven by a turbomolecular pump controller 29 (hereinafter referred to as TMP controller 29). The TMP controller 29 (first controller) is electrically connected to the main controller 10, which controls the entire exhaust gas treatment system, and the pest control device controller 49 (second controller), which controls the pest control device 4. Alternatively, the TMP controller 29 and the pest control device controller 49 may be integrated into one unit.

[0041] The TMP controller 29 controls the drive of the motor MT of the turbomolecular pump 2 according to the instruction signal from the main controller 10, and outputs the process signal (described later) to the pest control controller 49 at a predetermined timing. For example, the TMP controller 29 receives control signals (process start signal, process stop signal, etc.) for CVD processing, etching processing, etc., within the process chamber 1. If such a control signal is input, the TMP controller 29 drives or stops the motor MT of the turbomolecular pump 2.

[0042] Although not illustrated, the TMP controller 29 consists of hardware and software. The hardware includes a CPU that performs various calculations, a storage device such as ROM or HDD that stores programs used to execute these CPU-based calculations, RAM that serves as the CPU's operating area, and a communication interface that acts as an interface for sending and receiving data with other devices. The software is stored in the storage device and executed by the CPU. The controller's various functions are implemented by the CPU loading various programs stored in the storage device into RAM for execution. Further details regarding the control of the motor MT by the TMP controller 29 will be described later.

[0043] Figure 3 This is a structural diagram showing the detailed features of the pest control device 4. For example... Figure 3 As shown, the pest control device 4 includes a combustion furnace 40, a water scrubber device 41, a drain tank 42, and a solenoid valve 45. The combustion furnace 40 includes a combustion chamber 40A into which exhaust gas from the process chamber 1 flows and is introduced via a turbomolecular pump 2 and a dry pump 3, and a water scrubber treatment chamber 40B. Furthermore, a mixed fuel gas consisting of fuel and air is introduced into the combustion furnace 40 via the solenoid valve 45. Methane or propane is typically used as the fuel gas.

[0044] In combustion chamber 40A, the exhaust gas is combusted and decomposed at high temperature. The exhaust gas after combustion and decomposition flows into water scrubber treatment chamber 40B. In water scrubber treatment chamber 40B, spray water to capture dust (e.g., silica powder produced by the combustion and decomposition of silane) in the exhaust gas, or to collect water-soluble gaseous components (e.g., hydrofluoric acid produced by the combustion and decomposition of nitrogen trifluoride used as the cleaning gas in process chamber 1), thereby removing harmful components from the exhaust gas after combustion and decomposition. The removed harmful components flow into drain tank 42 together with the spray water.

[0045] A water scrubber device 41 is located downstream of the combustion furnace 40. Inside the cylindrical scrubber outer casing 41A, the water scrubber device 41 has a spray water area 41B and a gas contact area 41C with an annular filler designed to increase surface area. It is configured such that the gas (exhaust gas after combustion decomposition and dust collection) processed by the combustion chamber 40A and the water scrubber treatment chamber 40B flows into the interior from the lower part of the cylindrical scrubber outer casing 41A. Spray water from the spray water area 41B is also supplied to the gas contact area 41C via dripping. The exhaust gas after combustion decomposition and dust collection, flowing into the cylindrical scrubber outer casing 41A, flows upwards through the gas contact area 41C to the spray water area 41B. At this time, dust in the exhaust gas is captured through contact with the portion of the gas contact area 41C with the annular filler designed to increase surface area and the spray water from the spray water area 41B.

[0046] The drain tank 42 collects and stores the wastewater from the water scrubber treatment chamber 40B and the water scrubber device 41. Furthermore, a flow path for the exhaust gas is formed on the water surface of the drain tank 42. Thus, the exhaust gas introduced into the dust removal device 4 sequentially passes through the combustion chamber 40A, the water scrubber treatment chamber 40B, the water surface of the drain tank 42, and the water scrubber device 41 before being delivered to the electrostatic precipitator 5.

[0047] For the purifying device controller 49, a process signal (specific signal) is input from the TMP controller 29, and the operation (running) of the purifying device 4 is controlled based on this process signal. Specifically, the purifying device controller 49 controls the process during the period when the process signal is input to open the solenoid valve 45 and supply the mixed fuel gas toward the combustion chamber 40A. Furthermore, the hardware and software structures of the purifying device controller 49 are the same as those of the TMP controller 29, so detailed descriptions are omitted.

[0048] Next, use Figure 4 The control of turbomolecular pump 2 is explained. Figure 4 This is a flowchart illustrating the control processing sequence of the TMP controller 29. The TMP controller 29 continuously monitors the status (speed and current value) of the motor MT. If a start command for the turbomolecular pump 2 is input to the TMP controller 29, then the operation begins... Figure 4 The control process is shown.

[0049] First, the TMP controller 29 determines whether a rotation start command for the motor MT has been input (step S1). If a rotation start command for the motor MT has been input (step S1 / Yes), the TMP controller 29 performs acceleration processing on the motor MT (step S2). If the motor MT reaches the rated speed (step S3 / Yes), the delay time a is reset (step S4), and the process flag is reset (step S5).

[0050] Next, the TMP controller 29 reads the current of the motor MT (step S6) and determines the magnitude of the motor current and the threshold I (a predetermined threshold) (step S7). If the motor current is below the threshold I (step S7 / No), the TMP controller 29 increments the delay time a by "1" (step S8) and determines the magnitude of the delay time a and the predetermined time d (step S9). If the delay time a is greater than the predetermined time d (step S9 / Yes), the TMP controller 29 resets the process flag (step S10) and sets the process signal output to OFF. On the other hand, if the delay time a is less than the predetermined time d, the TMP controller 29 skips the processing in step S10 and proceeds to step S13.

[0051] In step S7, if the motor current exceeds the threshold I (step S7 / Yes), proceed to step S11. The TMP controller 29 resets the delay time a (step S11) and sets the process flag (step S12). If the process flag is set, the TMP controller 29 outputs a process signal (ON). Then, proceed to step S13.

[0052] Thus, when the motor current exceeds the threshold I during normal operation of the motor MT, i.e., during process processing, the process signal output continues by repeatedly performing the steps S7 / Yes → S11 → S12 → S13 / No → S6 → S7 / Yes. Then, when the motor current falls below the threshold I, the delay time a is added in step S8, but the process does not proceed to step S10 until the delay time a exceeds the predetermined time d in step S9, so the process flag is not reset. That is, after the process processing ends and the motor current falls below the threshold I, the process signal output continues until the predetermined time d has elapsed. Through this process, the pest control device 4 continues to operate even after the process processing ends until the predetermined time d has elapsed.

[0053] Next, the TMP controller 29 determines whether a rotation stop command for the motor MT has been input (step S13). If a rotation stop command for the motor MT has been input (step S13 / Yes), a delay process is performed (step S14), the process flag is reset (step S15), and the motor MT is decelerated (step S16). Next, the TMP controller 29 determines whether the rotation of the motor MT has actually stopped based on the speed detection signal from a speed detection sensor of the motor MT (not shown) (step S17). If the rotation of the motor MT has stopped, the TMP controller 29 returns to step S1; if the rotation of the motor MT has not stopped, it returns to step S16 and performs the motor MT deceleration process (step S16).

[0054] On the other hand, in step S13, if no rotation stop command for the motor MT is input (step S13 / No), the process returns to step S6. Furthermore, if no command is input in step S1, the TMP controller 29 remains in standby mode in step S1 until a rotation start command is input; if no command is input in step S3, the process returns to step S2.

[0055] Next, use Figure 5 The operating status of the motor MT, the change in the current value of the motor MT, and the on / off status of the process signal output from the TMP controller 29 to the pest control device controller 49 are explained. Figure 5 It is a time graph showing the changes in motor speed, motor current value, and process signal output from the start of rotation of motor MT of turbomolecular pump 2 to the stop over time.

[0056] (a) Change in the speed of motor MT

[0057] At time t1, if a motor rotation start command is input to TMP controller 29, then TMP controller 29 starts the rotation of motor MT of turbomolecular pump 2. Motor MT accelerates, and the speed of motor MT increases (see reference). Figure 4 Step S2). Then, at time t2, the speed of motor MT reaches the rated speed (refer to step S2). Figure 4 Step S3). If the speed of motor MT reaches the rated speed, the speed of motor MT is maintained at a constant value. That is, during the period from time t2 to time t10, the speed of motor MT is maintained at the rated speed and it is in normal operation. At time t10, if a motor rotation stop command is input to TMP controller 29 (refer to step S3), Figure 4 Step S13 / is), then the motor MT of turbomolecular pump 2 is decelerated (refer to...). Figure 4 Step S14), finally stopping at time t12 (refer to...) Figure 4 Step S17 / is).

[0058] (b) Changes in the current of motor MT

[0059] From the moment t1 when the motor rotation start command is input to the TMP controller 29, the current of the motor MT instantaneously rises to its maximum value until the motor MT reaches its rated speed at moment t2, during which time the current of the motor MT remains at its maximum value. Then, at moment t2, the current of the motor MT drops to its idle speed value.

[0060] During the period when motor MT is in normal operation (time t2 to time 10), if process processing is performed in process chamber 1, exhaust gas will be discharged from process chamber 1 along with the process processing. Since turbomolecular pump 2 draws in and ejects the exhaust gas, the motor load increases, and the motor current temporarily increases. For example, if in Figure 5 When process processing is performed at points P1 to P7, the increase in motor current corresponds to the load, ranging from the current at idle speed of motor MT to a value less than the maximum value of motor current. In this embodiment, the threshold I is set to a value greater than the current at idle speed of motor MT and less than the maximum value of motor current, for example, it is set to approximately 25% of the maximum value of motor current. Thus, during process processing, a state is reached where the motor current exceeds the threshold I. In other words, if the motor current value exceeds the threshold I, it can be inferred that process processing is underway.

[0061] (c) On / off of process signals

[0062] During the period from when the motor MT starts rotating, reaches its rated speed, and the process processing in process chamber 1 begins (time t1 to time t3), the process signal (specific signal) is disconnected (see reference). Figure 4 Step S5). Then, while the motor MT is operating at its rated speed (normal operation), at time t3 when the motor current value exceeds the threshold I (specific state), the process signal is turned on, and the process signal is output from the TMP controller 29 to the pest control device controller 49 (see reference). Figure 4 (Step S12). If a process signal is input to the purifying device controller 49, the solenoid valve 45 is opened to introduce the mixed fuel gas into the combustion chamber 40A for purifying the exhaust gas.

[0063] Then, if a predetermined time d elapses from the end of the process at time t4, the process signal switches to off. That is, during the period from the start of the process at time t3 to the end of the process and after the predetermined time d elapses at time t5 (times t3 to t5), the process signal is on. Therefore, the pest control device 4 operates during the period from time t3 to time t5, and stops operating after time t5. Then, if the process starts at time t6, the process signal is on again, and the pest control device 4 starts operating; if the process signal is off at time t8, the operation of the pest control device 4 stops.

[0064] In this embodiment, "stopping the operation of the purifying device 4" includes both completely stopping the operation of the purifying device 4 and setting the purifying device 4 to standby mode (standby state) to stop the purifying treatment of the exhaust gas. That is, it is sufficient to at least stop the purifying treatment (purifying operation) performed by the purifying device 4. In addition, in standby mode, the consumption of the aforementioned mixed fuel gas by the purifying device 4 is suppressed, resulting in a state that maintains the required marginal combustion state.

[0065] Furthermore, if the process begins at time t9, the process signal is turned on, and at time t11, a predetermined time d elapses after the motor rotation stop command is input to the TMP controller 29, the process signal is turned off. That is, from the time the motor rotation stop command is received until the predetermined time d elapses, the pest control device 4 is operated.

[0066] Here, the specified time d is determined by taking into account the time required for the exhaust gas to flow from the turbomolecular pump 2 to the pest control device 4. For example, if the time until the exhaust gas discharged from the turbomolecular pump 2 is completely introduced into the pest control device 4 is 10 seconds, the specified time d is set to 12 seconds, which is slightly longer than 10 seconds. This is to ensure that the exhaust gas discharged from the turbomolecular pump 2 is reliably controlled by the pest control device 4.

[0067] The exhaust gas treatment system configured as described above can achieve the following effects.

[0068] Since the TMP controller 29, which controls the turbomolecular pump 2, can accurately detect whether the process is in progress based on the current value of the motor MT (the state of the motor MT), it is not necessary to input a signal indicating whether the process is in progress from the main controller 10 or other controllers to the TMP controller 29.

[0069] Furthermore, the purifying device controller 49 can be controlled based on process signals input from the TMP controller 29, so that the purifying device 4 operates only during process handling. Therefore, it is no longer necessary to continuously supply mixed fuel gas to the purifying device 4. Specifically, the mixed fuel gas can be supplied to the combustion furnace 40 only during process handling by opening the solenoid valve 45. This prevents the unnecessary supply of mixed fuel gas to the purifying device 4, enabling energy-efficient operation of the purifying device 4. Figure 5 In the example, since the operation of the pest control device 4 can be stopped during the periods t1 to t3, t5 to t6, t8 to t9, and t11 to t12, a greater energy saving effect can be expected compared to the case where the pest control device 4 is operated from time t1 to time t12.

[0070] Furthermore, since a delay time 'a' is set for disconnecting the process signal, which takes into account the time (predetermined time 'd') until the exhaust gas discharged from the turbomolecular pump 2 is reliably introduced into the purifying device 4 for purifying, the exhaust gas discharged from the turbomolecular pump 2 can be reliably introduced into the purifying device 4 for purifying. Moreover, since the purifying device 4 only needs to be controlled based on the process signal from the TMP controller 29, the control processing of the purifying device controller 49 is simpler. In addition, since control can be performed solely through the input and output of signals between the TMP controller 29 and the purifying device controller 49, there is also the advantage of simplifying the control of the exhaust gas treatment system.

[0071] (A variation of the first embodiment)

[0072] In the above implementation methods, such as Figure 5 As shown, a structure can be implemented that disables the output of the process signal only for a specific time ta starting from time t2. Since the motor current fluctuates after the motor MT reaches its rated speed, there is a possibility that the motor current may exceed the threshold I even when not in process operation. Even in such cases, by simply disabling the output of the process signal for the specific time ta, the operation of the purifying device 4 can be prevented even when not in process operation, thus enabling further energy-saving operation. Furthermore, the specific time ta only needs to be sufficient to minimize the fluctuation of the motor current; for example, setting it to approximately 10 seconds is sufficient.

[0073] (Second Implementation)

[0074] Next, the exhaust gas treatment system according to the second embodiment of the present invention will be described. In the first embodiment, a structure is used where one removal device 4 is provided for each turbomolecular pump 2, but in the second embodiment, a structure is used where one removal device 4 is provided for multiple turbomolecular pumps. Therefore, the control method of the removal device 4 differs from that in the first embodiment. Hereinafter, the second embodiment will be described focusing on this difference.

[0075] Figure 6 This is an overall structural diagram of the exhaust gas treatment system according to the second embodiment of the present invention. Figure 6 As shown, in the second embodiment, turbomolecular pumps 2A, 2B, and 2C are installed in process chambers 1A, 1B, and 1C, and a dry pump 3 and a pest control device 4 are installed downstream of the three turbomolecular pumps 2A, 2B, and 2C. Furthermore, in Figure 6 The illustrations of the electric dust collection device 5 and the central scrubber 6 are omitted in the text.

[0076] For the pest control device controller 49 of the pest control device 4, process signals A, B, and C are input from the TMP controllers (not shown) of the turbomolecular pumps 2A, 2B, and 2C, respectively. The connection / disconnection of process signals A, B, and C is the same as in the first embodiment (see [reference]). Figure 4 , Figure 5 The pest control device controller 49 controls the operation of the pest control device 4 based on process signals A, B, and C.

[0077] In the second embodiment, the operating level of the pest control device 4 is preset to four levels. Operating level 0 is operation stopped, operating level 1 is operation at 33% load, operating level 2 is operation at 66% load, and operating level 3 is operation at 100% load. This is because one pest control device 4 is installed for each of the three process chambers 1A, 1B, and 1C, so the operating level of the pest control device 4 is set to four levels: operation stopped (including standby operation), 33% load, 66% load, and 100% load.

[0078] Furthermore, in the second embodiment, the difference in operating level is the difference in the flow rate of the mixed fuel gas supplied to the purifying device 4. For example, operating level 1 is the solenoid valve 45 (see reference 1). Figure 3 The opening degree is set to a specified degree (e.g., 33%), and the flow rate of the mixed fuel gas becomes approximately 33% of the operating rate at 100% load. The same applies to operating level 2.

[0079] Furthermore, the pest control device controller 49 controls the operation of the pest control device 4 by switching the operating level based on the total number of process signal inputs. Specifically, a control program is loaded to select operating level 0 (pest control operation stopped) when the number of process signal inputs is 0, operating level 1 when the number of process signal inputs is one, operating level 2 when the number of process signal inputs is two, and operating level 3 when the number of process signal inputs is three.

[0080] Figure 7 This is a time graph showing the changes in the operating status of the pest control device 4. For example... Figure 7 As shown, when process signals A, B, and C are all disconnected, the number of process signal inputs is 0, so the pest control device controller 49 stops the operation of the pest control device 4.

[0081] If at time t1, process signal A and process signal C are turned on and input to the pest control device controller 49, then the number of process signal inputs becomes two, and the pest control device controller 49 operates the pest control device 4 at operating level 2 (66% load).

[0082] If at time t2, process signal A becomes disconnected, then the number of process signal inputs becomes one, so the pest control controller 49 operates the pest control device 4 at operating level 1 (33% load).

[0083] If at time t3, process signals A, B, and C are all turned on, then the number of process signal inputs becomes three. Therefore, the pest control device controller 49 operates the pest control device 4 at operating level 3 (100% load).

[0084] If at time t4, process signal A and process signal C become disconnected, then the number of process signal inputs becomes one, so the pest control device controller 49 operates the pest control device 4 at operating level 1 (33% load).

[0085] Thus, according to the second embodiment, similar to the first embodiment, the unnecessary consumption of mixed fuel gas can be suppressed, and energy-saving operation of the purifying device 4 can be achieved. Furthermore, the operation of the purifying device 4 can be stopped (operation level 0) even without process signal input, resulting in higher energy-saving effects. Moreover, it is also expected that the number of purifying devices 4 can be reduced.

[0086] Furthermore, when atmospheric air flows within the exhaust gas treatment system, it flows from process chambers 1A, 1B, and 1C through turbomolecular pumps 2A, 2B, and 2C to the scavenging device 4. In this condition, turbomolecular pumps 2A, 2B, and 2C operate at idle speed, and the motor current value does not exceed the threshold I (see reference). Figure 5The process signal is disconnected. Therefore, since no process signal is input to the pest control device controller 49, the pest control device 4 will not operate unnecessarily. That is, since this embodiment can operate the pest control device 4 only during process processing and stop its operation when the atmosphere is flowing within the system, energy-saving effects can be expected.

[0087] (A variation of the second embodiment)

[0088] In the second embodiment described above, the operating level of the pest control device 4 is changed based on the number of process signals input to the pest control device controller 49. Alternatively, the current values ​​of each motor MT of the turbomolecular pumps 2A, 2B, and 2C can be input to the pest control device controller 49, and the pest control device controller 49 can sum the current values ​​of each motor MT and change the operating level of the pest control device 4 based on the sum.

[0089] In this case, the pest control device controller 49 determines whether the total value of the motor current is (a) equivalent to the value of the idle state, (b) exceeds the value of the value of the idle state but is below the threshold Ia, (c) exceeds the threshold Ia but is below the threshold Ib, or (d) exceeds the threshold Ib but is below the threshold Ic, and determines the operating level based on its determination result.

[0090] In addition, the threshold Ia is set to a value slightly higher than the value of the current flowing through a motor of one turbomolecular pump in the process, the threshold Ib is set to a value slightly higher than the value of the sum of the currents flowing through two turbomolecular pumps in the process, and the threshold Ic is set to a value slightly higher than the value of the sum of the currents flowing through three turbomolecular pumps in the process.

[0091] Figure 8 This is a timeline showing the changes in the operating status of the pest control device 4 in the relevant modified example. For example... Figure 8 As shown, since the total value of motor current A, B, and C is equivalent to the value in the idle state, the pest control device controller 49 stops the operation of the pest control device 4 (operation level 0).

[0092] At time t1, since the total value of motor current A, B, and C exceeds the threshold Ia and becomes below the threshold Ib, the pest control device controller 49 operates the pest control device 4 at operating level 2 (66% load).

[0093] At time t2, since the total value of motor current A, B, and C exceeds the value equivalent to the idle state and falls below the threshold Ia, the pest control device controller 49 operates the pest control device 4 at operating level 1 (33% load).

[0094] At time t3, since the total value of motor current A, B, and C exceeds the threshold Ib and falls below the threshold Ic, the pest control device controller 49 operates the pest control device 4 at operating level 3 (100% load).

[0095] At time t4, since the total value of motor current A, B, and C exceeds the value equivalent to the idle state and falls below the threshold Ia, the pest control device controller 49 operates the pest control device 4 at operating level 1 (33% load).

[0096] Even when using the motor current value as in this variant, the pest control device 4 can be operated in an energy-saving manner, just like in the second embodiment. Because this variant changes the operating level based on the motor current value, even when the processing capacities of process chambers 1A, 1B, and 1C are different, the pest control device 4 can be operated appropriately by setting the thresholds Ia, Ib, and Ic.

[0097] Furthermore, this invention is not limited to the embodiments described above. Various modifications can be made without departing from the spirit of the invention, and all technical matters included in the technical concept described in the claims are subject to this invention. The foregoing embodiments are preferred examples, but those skilled in the art can implement various alternatives, modifications, variations, or improvements based on the content disclosed in this specification, and these are included within the scope of the technology described in the appended claims.

[0098] For example, the pest control device 4 can be not only of the combustion type described above, but also of the plasma type or other forms. For example, in the case of a plasma-type pest control device, the power consumption of the plasma generator can be reduced.

[0099] Explanation of reference numerals in the attached figures

[0100] 2. Turbomolecular pump (vacuum pump)

[0101] 4. Pest Control Device

[0102] 29. Turbomolecular pump controller (Controller No. 1)

[0103] 40 Combustion Furnace

[0104] 45 Solenoid valve

[0105] 49. Pest Control Device Controller (Second Controller)

[0106] MT motor.

Claims

1. A vacuum pump that sucks and discharges exhaust gas, characterized by comprising: a motor as a drive source; a first controller that controls driving of the motor; the first controller monitors a state of the motor, and outputs a specific signal to an outside in a case where the state of the motor is a specific state other than a start time and a stop time, the specific state is a state where the motor is in normal operation and a current of the motor exceeds a prescribed threshold value, the first controller outputs the specific signal to the outside during a period where the motor is in normal operation and the current of the motor exceeds the prescribed threshold value, continues the output of the specific signal to the outside from when the current of the motor becomes equal to or less than the prescribed threshold value to when a prescribed time elapses, the prescribed time is set to a time that exceeds a time until exhaust gas discharged from the vacuum pump reaches a decontamination device provided on a downstream side of the vacuum pump.

2. The vacuum pump according to claim 1, characterized in that the outside is a second controller that controls an operation of the decontamination device.

3. The vacuum pump according to claim 1 or 2, characterized in that the first controller prohibits the output of the specific signal to the outside from a time point when the motor is started and becomes in normal operation to when a specific time elapses.

4. An exhaust gas processing system that comprises the vacuum pump according to claim 1 and a decontamination device that decontaminates exhaust gas discharged from the vacuum pump, characterized in that the decontamination device comprises: a combustion furnace that combusts exhaust gas; a solenoid valve that opens and closes in order to supply fuel gas to the combustion furnace; and a second controller that controls an opening and closing operation of the solenoid valve; the first controller monitors a state of the motor, and outputs a specific signal to the second controller in a case where the state of the motor is a specific state other than a start time and a stop time; and the second controller controls the opening and closing of the solenoid valve based on the specific signal from the first controller. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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