Cleaning method for dry vacuum pump and cleaning device for dry vacuum pump

Abstract

The present invention is a cleaning method for a dry vacuum pump in which deposits are accumulated, and the method includes: a startup check inspection for checking whether or not the dry vacuum pump can be started; a regeneration processing step that is executed when startup of the dry vacuum pump is not possible; and a life prolongation processing step that is executed when startup of the dry vacuum pump is possible or when startup of the dry vacuum pump becomes possible after the regeneration processing step. The regeneration processing step is a step of introducing high-temperature fluid into the dry vacuum pump to remove the accumulated deposits, and the life prolongation processing step is a step of introducing high-temperature fluid into the dry vacuum pump in a started state to remove the deposits remaining inside the dry vacuum pump.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a U.S. National Phase of International Application No. PCT / JP2022 / 047432 entitled “CLEANING METHOD FOR DRY VACUUM PUMP AND CLEANING DEVICE FOR DRY VACUUM PUMP,” and filed on Dec. 22, 2022. The entire contents of the above-listed application is hereby incorporated by reference for all purposes.TECHNICAL FIELD

[0002] The present invention relates to a cleaning method for a dry vacuum pump used in a vacuum facility, and a cleaning device for a dry vacuum pump used in the method.BACKGROUND ART

[0003] A dry vacuum pump is installed in an exhaust system of vacuum equipment such as a CVD device and an etching device used for manufacturing semiconductors, liquid crystal panels, etc. Since such a dry vacuum pump sucks post-reaction process gases discharged from a processing device such as a vacuum chamber, it is known that deposits of powder, liquids, gel-like substances, etc., are adhered / accumulated inside the dry vacuum pump due to long-term use, and in the worst case, solidified deposits cause the dry vacuum pump to be unable to start.

[0004] In order to avoid the aforementioned trouble, conventionally, the dry vacuum pump having been operated is periodically removed and overhauled, but such overhauling requires considerable time and cost.

[0005] As a conventional technique that can solve the problem related to such overhauling, for example, the following Patent Literature 1 (Japanese Laid-Open Patent Publication No. 2021-195893) discloses a vacuum pump that exhausts gas by rotating rotor blades of a turbo molecular pump. This vacuum pump includes a cleaning function unit for a cleaning function that cleans deposits inside the vacuum pump, and a deposits detection function unit for a deposits detection function that detects the deposits. According to this technique, it is possible to provide a vacuum pump capable of removing deposits without overhauling and further capable of detecting that removal of the deposits has been completed.CITATION LISTPatent Literature

[0006] [PTL 1] Japanese Laid-Open Patent Publication No. 2021-195893SUMMARY OF INVENTIONTechnical Problem

[0007] However, the aforementioned conventional technique has the following problems.

[0008] That is, when the vacuum pump is equipped with the cleaning function unit, the deposit detection function unit, and the like, if a trouble occurs in the cleaning function unit, the deposit detection function unit, or the like even though the vacuum pump itself has no problem in its function, a situation in which the use of the vacuum pump must be stopped may arise. In addition, since a vacuum pump equipped with various functions has a complicated structure, if overhauling becomes necessary, it will take more time and cost than the conventional vacuum pump. Ultimately, it is desirable to perform so-called swap maintenance in which an operating vacuum pump is replaced with an auxiliary pump of the same type, instead of incorporating a maintenance mechanism in the vacuum pump itself. However, a dry vacuum pump cleaning method capable of regenerating or prolonging the life of (comparable to overhauling) a dry vacuum pump that is unable to start due to solidified deposits, in a simpler manner, has not yet been realized.

[0009] Therefore, the major object of the present invention is to provide: a dry vacuum pump cleaning method capable of regenerating or prolonging the life of a dry vacuum pump by removing deposits adhered to the inside the pump in a shorter time and more easily than overhauling; and a dry vacuum pump cleaning device used in the method.Solution to Problem

[0010] In order to achieve the above object, as shown in FIG. 1 and FIG. 2, the present invention provides a cleaning method for a dry vacuum pump in which deposits are accumulated, as follows.

[0011] That is, the cleaning method includes: a startup check inspection S3 for checking whether or not the dry vacuum pump can be started; a regeneration processing step S4 that is executed when startup of the dry vacuum pump is not possible; and a life-prolongation processing step S6 that is executed when startup of the dry vacuum pump is possible or when startup of the dry vacuum pump becomes possible after the regeneration processing step S4. The regeneration processing step S4 is a step of introducing high-temperature fluid into the dry vacuum pump to remove the accumulated deposits. The life-prolongation processing step S6 is a step of introducing high-temperature fluid into the dry vacuum pump in a started state to remove the deposits remaining inside the dry vacuum pump.

[0012] The present invention provides the following effects, for example.

[0013] Since either the regeneration processing step or the life-prolongation processing step is selected and executed according to whether the dry vacuum pump can be started, which depends on the deposits accumulated inside, the deposits inside the dry vacuum pump can be efficiently removed.

[0014] In the present invention, the high-temperature fluid is preferably obtained by heating at least one fluid selected from the group consisting of air, nitrogen, oxygen, argon, hydrofluoric acid, and chlorine trifluoride, to a temperature within a range of 50° C. or higher and 400° C. or lower.

[0015] In this case, most of the deposits accumulated inside the dry vacuum pump can be chemically or physically removed. If the temperature of the high-temperature fluid is lower than 50° C., it may be difficult to reduce the viscosity of the deposits through heating. On the contrary, if the temperature of the high-temperature fluid exceeds 400° C., a seal member or the like attached to the dry vacuum pump may be adversely affected.

[0016] In the present invention, in the regeneration processing step and the life-prolongation processing step, it is preferable to introduce active species into the dry vacuum pump, in addition to the high-temperature fluid. In this case, if the deposits are mainly composed of a strongly adhesive substance such as SiO2 (silicon dioxide), for example, the deposits removal effect can be particularly enhanced.

[0017] Moreover, when the high-temperature fluid is introduced into the dry vacuum pump, it is preferable to vary the pressure of the high-temperature fluid, and it is also preferable to repeatedly perform start and stop of the dry vacuum pump, simultaneously with introduction of the high-temperature fluid into the dry vacuum pump.

[0018] A “dry vacuum pump cleaning device” as a second aspect of the present invention is a device for executing the aforementioned method, and the dry vacuum pump cleaning device is configured as shown in FIG. 3, for example.

[0019] The cleaning device includes: an inlet pipe 14 connected to an intake port of a dry vacuum pump 12; an outlet pipe 16 connected to an exhaust port of the dry vacuum pump 12; a high-temperature fluid supply means 18 configured to supply high-temperature fluid into the dry vacuum pump 12 through the inlet pipe 14; an atmospheric pressure exhaust line 16a and a reduced pressure exhaust line 16b that are formed by branching a downstream end of the outlet pipe 16, and are capable of switching a gas flow destination; a vacuum pump 20 disposed in the reduced pressure exhaust line 16b; and a detoxification device 22 that is disposed downstream of the atmospheric pressure exhaust line 16a and the reduced pressure exhaust line 16b, and is configured to detoxify exhaust gas discharged from the dry vacuum pump 12.

[0020] In the present invention, it is preferable that the cleaning device further includes an active species supply means 24 configured to supply active species into the dry vacuum pump 12 through the inlet pipe 14.

[0021] In addition, it is preferable that the outlet pipe 16 is equipped with a trap device 26 configured to trap components other than the gas discharged from the dry vacuum pump 12.

[0022] Furthermore, in the present invention, the cleaning device preferably includes a heating device 28 configured to heat the dry vacuum pump 12 from the outside. In particular, heating means of the heating device 28 is preferably induction heating.

[0023] In addition, the cleaning device preferably includes a preheating chamber configured to preheat a dry vacuum pump 12 next in line to be subjected to cleaning work.Advantageous Effects of Invention

[0024] According to the present invention, it is possible to provide: a dry vacuum pump cleaning method capable of regenerating or life-prolonging a dry vacuum pump by removing deposits adhered to the inside the pump in a shorter time and more easily than overhauling; and a dry vacuum pump cleaning device used in the method.BRIEF DESCRIPTION OF DRAWINGS

[0025] FIG. 1 is a flowchart showing an example of a dry vacuum pump cleaning method according to the present invention.

[0026] FIG. 2 is a flowchart showing subroutines in FIG. 1, in which FIG. 2A shows a subroutine of a regeneration processing step and FIG. 2B shows a subroutine of a life-prolongation processing step.

[0027] FIG. 3 illustrates an overview of a dry vacuum pump cleaning device according to an embodiment of the present invention.DESCRIPTION OF EMBODIMENT

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0029] FIG. 1 is a flowchart showing an example of a dry vacuum pump cleaning method according to the present invention, and FIG. 2 is a flowchart showing subroutines in FIG. 1. FIG. 3 illustrates an overview of a dry vacuum pump cleaning device 10 according to an embodiment of the present invention. The dry vacuum pump cleaning device 10 of the present embodiment is a device for regeneration and life-prolongation of a dry vacuum pump 12 in which deposits are accumulated. As shown in FIG. 3, the cleaning device 10 is roughly composed of an inlet pipe 14, an outlet pipe 16, a high-temperature fluid supply means 18, a vacuum pump 20, a detoxification device 22, and an active species supply means 24 that is provided according to need. A control system, a cooling water system, and the like (not shown) are added to these components.

[0030] The inlet pipe 14 is connected to an intake port of the dry vacuum pump 12 mounted in a cleaning chamber 32 covered by a hood 30, and is used to introduce high-temperature fluid or the like into the dry vacuum pump 12. Therefore, a downstream end of a fluid supply pipe 50 of the high-temperature fluid supply means 18 (described later) is connected to the inlet pipe 14. Furthermore, a pressure gauge 34 for measuring the internal pressure is attached to the inlet pipe 14.

[0031] The outlet pipe 16 is connected to an exhaust port of the dry vacuum pump 12 mounted in the cleaning chamber 32 covered with the hood 30, and is used to transport high-temperature fluid that has flowed through the dry vacuum pump 12 and become exhaust gas, deposits discharged from the dry vacuum pump 12 by the high-temperature fluid, and the like.

[0032] The outlet pipe 16 branches at its downstream end so that two branch pipes are formed. One of the branch pipes serves as an atmospheric pressure exhaust line 16a while the other branch pipe serves as a reduced pressure exhaust line 16b. The vacuum pump 20 is disposed at an intermediate point of the reduced pressure exhaust line 16b. In addition, a switching valve 36 and a switching valve 38 are attached to the atmospheric pressure exhaust line 16a and the reduced pressure exhaust line 16b, respectively. Switching these valves allows selection of a line through which exhaust gas or the like flows, between the atmospheric pressure exhaust line 16a and the reduced pressure exhaust line 16b. In the state shown in FIG. 3, since the switching valve 36 is closed and the switching valve 38 is open, the exhaust gas or the like flows through the reduced pressure exhaust line 16b.

[0033] In the present embodiment, a trap device 26 (described later) is mounted upstream of the branching point of the outlet pipe 16, and an outlet valve 40 is mounted between the trap device 26 and the branching point of the outlet pipe 16. The outlet value is operated to close when the dry vacuum pump 12 to which the outlet pipe 16 is connected is pressurized. Furthermore, pressure gauges 42, 44, and 46 for measuring the internal pressure are attached to the trap device 26, the atmospheric pressure exhaust line 16a, and the reduced pressure exhaust line 16b, respectively.

[0034] The trap device 26 is a device that traps, in its internal space, deposits of powder, liquids, or gel-like substances discharged from the dry vacuum pump 12 through the outlet pipe 16, to prevent the deposits from flowing downstream of the outlet pipe 16, and the inside of the trap device 26 is cooled by cooling water (not shown).

[0035] The high-temperature fluid supply means 18 is used to supply high-temperature fluid through the inlet pipe 14 into the dry vacuum pump 12 in which deposits are adhered. The high-temperature fluid supply means 18 includes a fluid heating device 48 equipped with a heat source such as an electric heater, and a fluid supply pipe 50 that delivers the high-temperature fluid heated by the fluid heating device 48 to the inlet pipe 14.

[0036] The fluid to be heated by the fluid heating device 48 is preferably at least one selected from the group consisting of air, nitrogen, oxygen, argon, hydrofluoric acid, and chlorine trifluoride. The temperature of the high-temperature fluid obtained by heating the fluid with the fluid heating device 48 is preferably within a range of 50□ or higher and 400□ or lower, as described above.

[0037] In the embodiment shown in FIG. 3, air (CDA; Clean Dry Air) and nitrogen (N2) are supplied to the fluid heating device 48. Specifically, CDA is supplied to the fluid heating device 48 through a CDA supply line 52 in which the gas supply amount is controlled by a mass flow controller 52a. Likewise, N2 is supplied to the fluid heating device 48 through an N2 supply line 54 in which the gas supply amount is controlled by a mass flow controller 54a. An open / close valve 52b is operated to open when CDA is supplied to the fluid heating device 48 through the CDA supply line 52, and an open / close valve 54b is operated to open when N2 is supplied to the fluid heating device 48 through the N2 supply line 54.

[0038] The detoxification device 22 is a device that detoxifies the exhaust gas discharged from the dry vacuum pump 12 through the outlet pipe 16 and the atmospheric pressure exhaust line 16a or the reduced pressure exhaust line 16b. The detoxification device 22 may be of any type, such as combustion type, thermal decomposition type, wet type, atmospheric pressure plasma type, adsorption type, water scrubber type, etc., but it is most suitable to use the atmospheric pressure plasma type, taking into consideration space efficiency, detoxification efficiency, and the like of the device. In FIG. 3, reference numeral 56 denotes a pipe for releasing, into the atmosphere, the exhaust gas detoxified by the detoxification device 22, and reference numeral 58 denotes a fan that sucks the exhaust gas.

[0039] The active species supply means 24 is provided according to need to supply active species, such as F (fluorine) radicals and O (oxygen) radicals, through the inlet pipe 14 into the dry vacuum pump 12 in which deposits are adhered. The active species supply means 24 includes: an active species generation device 60 equipped with a plasma generation means such as a high-frequency induction coil for generating ICP (inductively coupled plasma); and an active species supply pipe 62 that supplies the active species generated by the active species generation device 60 to the inlet pipe 14. The active species supply pipe 62 is branched at an intermediate point to provide a branch pipe 62a. A downstream end of the branch pipe 62a is connected to an upstream end part of the outlet pipe 16, so that the active species can also be supplied from the outlet pipe 16 side into the dry vacuum pump 12. An open / close valve 64 is attached to the branch pipe 62a, and the open / close valve 64 is operated to open when the active species are supplied to the upstream end part of the outlet pipe 16.

[0040] Ar (argon) gas necessary for generating plasma and NF3 and O2 as raw materials of active species are supplied to the active species generation device 60. Specifically, Ar gas is supplied to the active species generation device 60 through an Ar supply line 66 in which the gas supply amount is controlled by a mass flow controller 66a, NF3 is supplied to the active species generation device 60 through an NF3 supply line 68 in which the gas supply amount is controlled by a mass flow controller 68a, and O2 is supplied to the active species generation device 60 through an O2 supply line 70 in which the gas supply amount is controlled by a mass flow controller 70a. An open / close valve 66b is operated to open when Ar gas is supplied to the active species generation device 60 through the Ar supply line 66, an open / close valve 68b is operated to open when NF3 is supplied to the active species generation device 60 through the NF3 supply line 68, and an open / close valve 70b is operated to open and simultaneously an open / close valve 65 is operated to close when O2 is supplied to the active species generation device 60 through the O2 supply line 70.

[0041] When the active species supply means 24 is provided, it is preferable to mount a differential exhaust pipe 72 that allows the inlet pipe 14 to communicate with the outlet pipe 16 as shown in FIG. 3. The reason is as follows. In order to generate active species in the active species generation device 60, it is necessary to start a plasma generation means (not shown) to turn NF3, O2, etc., into plasma. For this purpose, it is necessary to evacuate the inside of the plasma generation means by actuating the vacuum pump 20. However, if the inside of the dry vacuum pump 12 is almost completely blocked by deposits, evacuation cannot be performed. In such a case, by operating an open / close valve 74 disposed in the differential exhaust pipe 72 to open, evacuation of the inside of the plasma generation means by the vacuum pump 20 becomes possible, whereby the active species supply means 24 can be operated.

[0042] The dry vacuum pump cleaning device 10 of the present embodiment configured as described above further includes the following components.

[0043] First, in the case where the dry vacuum pump 12 to be regenerated or whose life is to be prolonged by the cleaning device 10 is composed of a lower-stage main pump 12a and an upper-stage booster pump 12b as shown in FIG. 3, if the inside of the pump is blocked when high-temperature fluid is introduced into the pump from the inlet pipe 14 connected to the booster pump 12b side, the main pump 12a cannot be sufficiently heated. For this reason, a heating device 28 for heating the main pump 12a is provided. As heating means of the heating device 28, a known method can be adopted, but it is particularly preferable to use induction heating (IH) that can heat the casing of the main pump 12a made of iron, directly from the surface. The heating temperature by the heating device 28 is preferably set to 300□ or lower, and more preferably set to 250□ or lower, to prevent an O-ring (made of fluororubber) of the pump (not shown) from being melted. Depending on the structure of the pump, the booster pump may be heated.

[0044] The dry vacuum pump cleaning device 10 of the present embodiment is provided with a second fluid heating device 76. In the second fluid heating device 76, high-temperature fluid is generated by heating N2 supplied through a branch pipe 54c branching from the N2 supply line 54. CDA may also be used in addition to N2. The generated high-temperature fluid is supplied to the upstream end part of the outlet pipe 16 through the fluid supply pipe 78. Reference numeral 54d in FIG. 3 denotes an open / close valve that is operated to open when the second fluid heating device 76 is used.

[0045] Furthermore, in the dry vacuum pump cleaning device 10 of the present embodiment, a local booth exhaust pipe 80 allows the space inside the cleaning chamber 32 covered with the hood 30 to communicate with the atmospheric pressure exhaust line 16a. Therefore, even if harmful exhaust gas leaks into the cleaning chamber 32 during replacement work or the like for the dry vacuum pump 12, the leaked exhaust gas is sucked through the local booth exhaust pipe 80, the atmospheric pressure exhaust line 16a, the detoxification device 22, and the fan 58, thereby securing safety.

[0046] In the dry vacuum pump cleaning device 10 of the present embodiment, a preheating chamber (not shown) for preheating a dry vacuum pump 12 next in line to be subjected to cleaning work is provided adjacent to the cleaning chamber 32. The dry vacuum pump 12 that is placed in the preheating chamber and awaiting cleaning is also supplied with the high-temperature fluid for preheating.

[0047] The dry vacuum pump cleaning device 10 of the present embodiment configured as described above has a single cabinet 82 housing the components thereof, and this cabinet 82 is equipped with a housing exhaust pipe 84 that prevents harmful gases from accumulating in the cabinet 82.

[0048] Next, a dry vacuum pump cleaning method using the dry vacuum pump cleaning device 10 of the present embodiment will be described with reference to FIG. 1 and FIG. 2.

[0049] As shown in FIG. 1, the dry vacuum pump cleaning method of the present invention includes “pre-work inspection S1”, “dry vacuum pump mounting S2”, “startup check inspection S3”, “regeneration processing step S4” to be performed according to need, “startup check reinspection S5”, “life-prolongation processing step S6”, “post-work inspection S7”, and “dry vacuum pump dismounting S8” which are executed in this order. Among these steps, the “startup check inspection S3”, the “regeneration processing step S4”, and the “life-prolongation processing step S6” are particularly important.

[0050] The pre-work inspection S1 is a step of inspecting whether the reason for the dry vacuum pump 12 not being able to start is adhesion of deposits. The inside of the pump is viewed from the intake port or the exhaust port to check the state of the deposits. Furthermore, if necessary, the deposits are sampled and chemically analyzed (qualitatively analyzed). In addition, a rotor is manually rotated using a torque wrench, and if the torque at that time is equal to or lower than a predetermined reference value such as 24 N·m or 60 N·m, the “dry vacuum pump mounting S2” for mounting the dry vacuum pump 12 in the cleaning chamber 32 is executed. On the other hand, if the torque obtained when the rotor is manually rotated using the torque wrench exceeds the predetermined reference value, it is preferable to exclude the dry vacuum pump 12 from processing objects because the dry vacuum pump 12 cannot be regenerated.

[0051] Subsequently, for the dry vacuum pump 12 mounted in the cleaning chamber 32, current value logging is started, and the “startup check inspection S3” to check initial startup with atmospheric pressure exhaust is executed. If the dry vacuum pump 12 can be started, the “life-prolongation processing step S6” is executed. If the dry vacuum pump 12 cannot be started (startup is not possible), the “regeneration processing step S4” is executed. When startup is possible, initial characteristics such as conductance and exhaust characteristics may be measured in advance of the “regeneration processing step S4” or the “life-prolongation processing step S6”.

[0052] The “regeneration processing step S4” is mainly a step of introducing high-temperature fluid into the dry vacuum pump 12 to remove deposits accumulated in the pump 12. As shown in FIG. 2A, “heating regeneration with atmospheric pressure exhaust S4.1”, “heating regeneration with vacuum exhaust S4.2”, and “cyclic exhaust S4.3” are executed in this order.

[0053] The heating regeneration with atmospheric pressure exhaust S4.1 is a process in which high-temperature fluid with a predetermined flow rate is introduced from the inlet pipe 14 into the dry vacuum pump 12 while controlling the pressure within a range that does not cause excessive pressurization, and the exhaust gas, etc., discharged from the dry vacuum pump 12 through the outlet pipe 16 are sent to the detoxification device 22 through the atmospheric pressure exhaust line 16a. After the heating regeneration with atmospheric pressure exhaust is performed for a predetermined time such as 70 minutes, for example, the heating regeneration with vacuum exhaust S4.2 is executed.

[0054] The heating regeneration with vacuum exhaust S4.2 is a process in which high-temperature fluid with a predetermined flow rate is introduced from the inlet pipe 14 into the dry vacuum pump 12 while controlling the pressure within a range that does not cause excessive pressurization, and the exhaust gas, etc., discharged from the dry vacuum pump 12 through the outlet pipe 16 are sent to the detoxification device 22 through the reduced pressure exhaust line 16b while being evacuated by the vacuum pump 20. After the heating regeneration with vacuum exhaust is performed for a predetermined time such as 15 minutes, for example, the cyclic exhaust S4.3 is executed.

[0055] The cyclic exhaust S4.3 is as follows. That is, high-temperature fluid is supplied from the inlet pipe 14 with the outlet valve 40 of the outlet pipe 16 being closed, to bring the inside of the dry vacuum pump 12 in a pressurized state with the high-temperature fluid. Thereafter, the outlet valve 40 is opened, whereby the high-temperature fluid inside the dry vacuum pump 12 is discharged all at once, and deposits inside the pump 12 are discharged by the momentum of high-temperature, high-pressure gas flow. The cyclic exhaust S4.3 is a process in which the series of steps is repeated a predetermined number of times such as 10 times, for example. In the cyclic exhaust S4.3, the exhaust gas, etc., discharged from the dry vacuum pump 12 are evacuated by the vacuum pump 20, and are sent to the detoxification device 22 through the reduced pressure exhaust line 16b.

[0056] After completing the regeneration processing step S4 as described above, the dry vacuum pump 12 is subjected to the “startup check reinspection S5” to check initial startup with atmospheric pressure exhaust. If regeneration is successful and the dry vacuum pump 12 can be started, the “life-prolongation processing step S6” is executed. If the dry vacuum pump 12 cannot be started (startup is not possible), the “regeneration processing step S4” is executed again. As for the number of times the regeneration processing step S4 is repeated because startup is not possible after the startup check reinspection S5, it is preferable to set an upper limit in advance, taking into consideration protection of the parts of the dry vacuum pump 12, economic efficiency, and the like.

[0057] The “life-prolongation processing step S6” is a step in which high-temperature fluid is introduced into the dry vacuum pump 12 that is being activated, and the deposits remaining inside the dry vacuum pump 12 are removed. As shown in FIG. 2B, “dry vacuum pump startup S6.1” and “cleaning work S6.2” are executed in this order. The dry vacuum pump startup S6.1 is literally a step of starting the dry vacuum pump 12.

[0058] The cleaning work S6.2 is a work step in which the aforementioned “heating regeneration with atmospheric pressure exhaust S4.1” and “heating regeneration with vacuum exhaust S4.2” are executed continuously and integrally. High-temperature fluid with a predetermined flow rate is introduced from the inlet pipe 14 into the dry vacuum pump 12 while controlling the pressure within a range that does not cause excessive pressurization, and the exhaust gas, etc., discharged from the dry vacuum pump 12 through the outlet pipe 16 are firstly sent to the detoxification device 22 through the atmospheric pressure exhaust line 16a. After a predetermined processing time such as 60 minutes, for example, has elapsed, the exhaust gas, etc., are switched to be sent to the detoxification device 22 through the reduced pressure exhaust line 16b, and are sent to the detoxification device 22 while being evacuated by the vacuum pump 20 for a predetermined time such as 30 minutes, for example.

[0059] Subsequently, the dry vacuum pump 12 that has completed the life-prolongation processing step S6 is subjected to the “post-work inspection S7”.

[0060] In this post-work inspection S7, exhaust characteristics and conductance of the dry vacuum pump 12 are inspected. If this inspection confirms that the performance of the dry vacuum pump 12 after the cleaning work S6.2 is restored, the current value logging is ended and the “dry vacuum pump dismounting S8” is performed to end the dry vacuum pump cleaning method of the present embodiment.

[0061] According to the dry vacuum pump cleaning method of the present embodiment, either the regeneration processing step S4 or the life-prolongation processing step S6 is selected and executed according to whether or not the dry vacuum pump 12 can be started, which depends on the deposits accumulated inside. Therefore, the deposits inside the dry vacuum pump 12 can be efficiently removed.

[0062] In the aforementioned embodiment, only the high-temperature fluid is introduced into the dry vacuum pump 12 in the regeneration processing step S4 and the life-prolongation processing step S6. However, if the deposits inside the dry vacuum pump 12 cannot be removed by the high-temperature fluid alone, active species such as F radicals generated by the active species supply means 24 may be introduced into the dry vacuum pump 12 together with the high-temperature fluid or separately from the regeneration processing step S4 and the life-prolongation processing step S6, to chemically decompose and remove the deposits.

[0063] In the aforementioned embodiment, the dry vacuum pump 12 is heated only by the high-temperature fluid. However, particularly in the regeneration processing step S4 that is performed on the dry vacuum pump 12 in which too much deposits are adhered that the pump 12 cannot start, it is preferable to heat the pump 12 from the main pump 12a side as well by using the heating device 28.

[0064] It is needless to say that the present invention can be modified in various other ways within the scope conceived by persons skilled in the art.REFERENCE SIGNS LIST10 dry vacuum pump cleaning device

[0066] 12 dry vacuum pump

[0067] 14 inlet pipe

[0068] 16 outlet pipe

[0069] 16a atmospheric pressure exhaust line

[0070] 16b reduced pressure exhaust line

[0071] 18 high-temperature fluid supply means

[0072] 20 vacuum pump

[0073] 22 detoxification device

[0074] 24 active species supply means

[0075] 26 trap device

[0076] 28 heating device

Claims

1. A cleaning method for a dry vacuum pump in which deposits are accumulated, the method comprising:a startup check inspection for checking whether or not the dry vacuum pump can be started;a regeneration processing step that is executed when startup of the dry vacuum pump is not possible; anda life-prolongation processing step that is executed when startup of the dry vacuum pump is possible or when startup of the dry vacuum pump becomes possible after the regeneration processing step, whereinthe regeneration processing step is a step of introducing high-temperature fluid into the dry vacuum pump to remove the accumulated deposits, andthe life-prolongation processing step is a step of introducing high-temperature fluid into the dry vacuum pump in a started state to remove the deposits remaining inside the dry vacuum pump.

2. The cleaning method for the dry vacuum pump according to claim 1, whereinthe high-temperature fluid is obtained by heating at least one fluid selected from the group consisting of air, nitrogen, oxygen, argon, hydrofluoric acid, and chlorine trifluoride, to a temperature within a range of 50° C. or higher and 400° C. or lower.

3. The cleaning method for the dry vacuum pump according to claim 1, whereinin the regeneration processing step and the life-prolongation processing step, active species are introduced into the dry vacuum pump in addition to the high-temperature fluid.

4. The cleaning method for the dry vacuum pump according to claim 1, whereinwhen the high-temperature fluid is introduced into the dry vacuum pump, the pressure of the high-temperature fluid is varied.

5. The cleaning method for the dry vacuum pump according to claim 1, whereinsimultaneously with introduction of the high-temperature fluid into the dry vacuum pump, start and stop of the dry vacuum pump are repeatedly performed.

6. A cleaning device for a dry vacuum pump for regeneration and life-prolongation of the dry vacuum pump in which deposits are accumulated, the device comprising:an inlet pipe connected to an intake port of the dry vacuum pump;an outlet pipe connected to an exhaust port of the dry vacuum pump;a high-temperature fluid supply means configured to supply high-temperature fluid into the dry vacuum pump through the inlet pipe;an atmospheric pressure exhaust line and a reduced pressure exhaust line that are formed by branching a downstream end of the outlet pipe, and are capable of switching a gas flow destination;a vacuum pump disposed in the reduced pressure exhaust line; anda detoxification device that is disposed downstream of the atmospheric pressure exhaust line and the reduced pressure exhaust line, and is configured to detoxify exhaust gas discharged from the dry vacuum pump.

7. The cleaning device for the dry vacuum pump according to claim 6, further comprising an active species supply means configured to supply active species into the dry vacuum pump through the inlet pipe.

8. The cleaning device for the dry vacuum pump according to claim 6, whereinthe outlet pipe is equipped with a trap device configured to trap components other than the exhaust gas discharged from the dry vacuum pump.

9. The cleaning device for the dry vacuum pump according to claim 6, further comprising a heating device configured to heat the dry vacuum pump from the outside.

10. The cleaning device for the dry vacuum pump according to claim 9, whereinheating means of the heating device is induction heating.

11. The cleaning device for the dry vacuum pump according to claim 6, further comprising a preheating chamber configured to preheat a dry vacuum pump next in line to be subjected to cleaning work.

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