阅读说明：本技术 真空泵及其使用的固定零件、排气端口、控制机构 (Vacuum pump, and fixing part, exhaust port and control mechanism used for vacuum pump ) 是由 山本一志 野中学 坂口祐幸 桦泽刚志 于 2018-12-25 设计创作，主要内容包括：本发明提供适合将堆积于真空泵内的流路的产物除去的真空泵、及其使用的固定零件、排气端口、控制机构。真空泵(P1)具备从吸气口(2)向排气口(3)转移的气体的流路(R)、将堆积于流路(R)的内壁面的产物除去的除去机构(RM),除去机构(RM)具备在流路(R)的内壁面一端开口的喷射孔(91、92、93),且为从该喷射孔(91、92、93)向前述流路(R)内喷射除去气体的构造。(The invention provides a vacuum pump suitable for removing products accumulated in a flow path in the vacuum pump, and a fixed part, an exhaust port and a control mechanism used by the vacuum pump. A vacuum pump (P1) is provided with a flow path (R) for gas transferred from an inlet (2) to an outlet (3), and a Removal Mechanism (RM) for removing products deposited on the inner wall surface of the flow path (R), wherein the Removal Mechanism (RM) is provided with ejection holes (91, 92, 93) that open at one end of the inner wall surface of the flow path (R), and has a structure for ejecting the removal gas from the ejection holes (91, 92, 93) into the flow path (R).)

1. A vacuum pump is characterized in that the vacuum pump is provided with a vacuum pump body,

comprises a rotary body, a support mechanism, a drive mechanism, an air inlet, an air outlet, a gas flow path, and a removal mechanism,

the rotating body is arranged in the outer casing,

the support mechanism rotatably supports the rotating body,

the driving mechanism drives the rotating body to rotate,

the suction port is used for sucking gas by the rotation of the rotating body,

the exhaust port is used for exhausting the gas sucked from the air suction port,

the flow path of the gas is transferred from the gas inlet to the gas outlet,

the removing means removes the product deposited on the inner wall surface of the flow path,

the removal means has an injection hole that opens at one end of the inner wall surface of the flow path, and is configured to inject a removal gas from the injection hole into the flow path.

2. Vacuum pump according to claim 1,

the apparatus is provided with a control means which functions as means for controlling any one of the pressure, flow rate, and injection time of the purge gas.

3. Vacuum pump according to claim 1,

a sensing means for sensing a supply state of the gas supply system is provided in the middle of the gas supply system for supplying the degassing gas to the ejection hole.

4. Vacuum pump according to claim 2,

a sensing means for sensing a supply state of the gas supply system is provided in the middle of the gas supply system for supplying the degassing gas to the ejection hole.

5. A vacuum pump according to claim 4,

the control means functions as means for outputting a signal necessary for adjusting the supply pressure or the supply flow rate of the purge gas to the ejection hole based on the result of sensing by the sensing means.

6. A vacuum pump according to claim 4,

the control means functions as: and a control unit for controlling the supply pressure and the supply flow rate of the purge gas to the injection hole, and outputting a signal necessary for adjusting the supply pressure and the supply flow rate of the purge gas to the injection hole or outputting a signal necessary for sounding an alarm when the estimated accumulation amount of the product exceeds a threshold value.

7. A vacuum pump according to any of claims 2 or 4 to 6,

the control means functions as means for supplying the purging gas to the ejection hole based on a command from an external device.

8. Vacuum pump according to claim 2,

the control of the injection time includes at least one of a control of a form of injecting the purge gas from the injection hole all the time and a control of a form of injecting the purge gas from the injection hole intermittently.

9. Vacuum pump according to claim 2,

the control of the flow rate includes at least one of a control of maintaining a constant flow rate of the removal gas injected from the injection hole and a control of increasing or decreasing the flow rate.

10. Vacuum pump according to claim 2,

the pressure control includes at least one of a control of maintaining a constant pressure of the removal gas injected from the injection hole and a control of supplying the removal gas injected from the injection hole so as to protrude from the injection hole.

11. Vacuum pump according to any of claims 1 to 10,

the purge gas is an inert gas.

12. Vacuum pump according to any of claims 1 to 10,

the degassing gas is a high-energy gas activated by an excitation mechanism.

13. Vacuum pump according to any of claims 1 to 10,

the degassing gas is a high-temperature gas heated by a heating means.

14. Vacuum pump according to any of claims 1 to 10,

the injection hole is provided in plural.

15. Vacuum pump according to any of claims 1 to 10,

the inner wall surface of the flow path is formed of a porous material,

the porous body of the porous material is used as the injection hole.

16. Vacuum pump according to claim 15,

the gas can be ejected and removed from the pores of the porous material into the flow path within the range of the non-shielding portion by shielding a part of the surface of the porous material constituting the inner wall surface of the flow path and forming a non-shielding portion without shielding the other part.

17. Vacuum pump according to claim 15,

a plate body having a surface area larger than an opening area of the injection hole is provided in the vicinity of an opening end of the injection hole, and the plate body is formed of a porous material, and a porous hole of the porous material is used as the injection hole.

18. Vacuum pump according to any of claims 1 to 17,

the flow path is a flow path formed in a shape of a screw groove formed between an outer periphery of the rotating body and a fixed member facing the rotating body, and has a structure in which one end of the injection hole opens on an inner wall surface in the vicinity of a downstream outlet of the flow path.

19. Vacuum pump according to any of claims 1 to 17,

the flow path is a flow path formed in a shape of a screw groove formed between an outer periphery of the rotating body and a fixed member facing the rotating body, and has a structure in which one end of the injection hole is opened in an inner wall surface near an upstream inlet of the flow path.

20. Vacuum pump according to any of claims 1 to 17,

the flow path is a flow path formed by a gap set between a rotary blade provided on an outer peripheral surface of the rotary body and a fixed blade positioned and fixed in the outer casing, and has a structure in which one end of the injection hole opens on an inner wall surface in the vicinity of a downstream outlet of the flow path.

21. Vacuum pump according to any of claims 1 to 17,

the flow path includes an exhaust port communicating with a downstream outlet of the flow path,

one end of the injection hole is opened to an inner wall surface of the exhaust port.

22. Vacuum pump according to any of claims 1 to 17,

the flow path is a flow path formed by a gap set between a rotor blade provided on an outer peripheral surface of the rotor and a fixed blade positioned and fixed in the outer casing, and the flow path includes an inner surface of a spacer that positions and fixes the fixed blade, and has a structure in which one end of the injection hole opens on an inner wall surface of the spacer.

23. Vacuum pump according to any of claims 1 to 17,

the flow path is a flow path formed by a gap set between a rotary blade provided on the outer peripheral surface of the rotary body and a fixed blade positioned and fixed in the outer casing, and has a structure in which one end of the injection hole opens on the outer surface of the fixed blade.

24. A vacuum pump according to claim 7,

the execution based on the command includes a process of outputting a maintenance request signal to the external device, and a process of outputting a signal necessary for supplying the purge gas when receiving a maintenance permission signal output from the external device based on the maintenance request signal.

25. Vacuum pump according to any of claims 1 to 24,

the inner wall surface of the flow path is coated with a material having higher non-adhesiveness or lower surface free energy than the constituent substrate of the flow path.

26. A vacuum pump according to claim 25,

the material of the coating is a coating member of fluororesin or fluorine-containing resin.

27. A stationary part constituting a flow path of a vacuum pump comprising a rotary body, a support mechanism, a drive mechanism, an air inlet, an air outlet, and a flow path of gas,

the rotating body is arranged in the outer casing,

the support mechanism rotatably supports the rotating body,

the driving mechanism drives the rotating body to rotate,

the suction port is used for sucking gas by the rotation of the rotating body,

the exhaust port is used for exhausting the gas sucked from the air suction port,

wherein the flow path of the gas is transferred from the inlet port to the outlet port,

the removal means for removing the product deposited on the inner wall surface of the flow path includes an injection hole having one end opened to the inner wall surface of the fixed component.

28. An exhaust port of a vacuum pump comprising a rotary body, a support mechanism, a drive mechanism, an air inlet, an exhaust port, and a gas flow path, the exhaust port constituting the exhaust port,

the rotating body is arranged in the outer casing,

the support mechanism rotatably supports the rotating body,

the driving mechanism drives the rotating body to rotate,

the suction port is used for sucking gas by the rotation of the rotating body,

the exhaust port is used for exhausting the gas sucked from the air suction port,

wherein the flow path of the gas is transferred from the inlet port to the outlet port,

the removal means for removing the product deposited on the inner wall surface of the flow path includes an injection hole having one end opening on the inner wall surface of the exhaust port.

29. A control mechanism for a vacuum pump comprising a rotary body, a support mechanism, a drive mechanism, an air inlet, an air outlet, a gas flow path, and a removal mechanism,

the rotating body is arranged in the outer casing,

the support mechanism rotatably supports the rotating body,

the driving mechanism drives the rotating body to rotate,

the suction port is used for sucking gas by the rotation of the rotating body,

the exhaust port is used for exhausting the gas sucked from the air suction port,

the flow path of the gas is transferred from the gas inlet to the gas outlet,

the removing means removes the product deposited on the inner wall surface of the flow path,

the removing means includes an injection hole having one end opened to an inner wall surface of the flow path,

the vacuum pump has a structure for ejecting and removing gas from the ejection hole into the flow path,

controlling any one of a pressure, a flow rate and an injection time of the removing gas injected from the injection hole into the flow path,

or outputting a signal necessary for adjusting the supply pressure or the supply flow rate of the purge gas,

or as a mechanism for outputting a signal necessary for sounding an alarm,

or a mechanism for supplying the purge gas to the ejection hole based on a command from an external device.

Technical Field

The present invention relates to a vacuum pump used as a gas exhaust mechanism for a processing chamber of a semiconductor manufacturing apparatus, a flat panel display manufacturing apparatus, a solar panel manufacturing apparatus, or another vacuum chamber, and a fixture, an exhaust port, and a control mechanism used for the vacuum pump, and particularly to a vacuum pump suitable for removing a product accumulated in a flow path in the pump.

Background

Sometimes TiF is formed as a reaction byproduct during its processing in semiconductor manufacturing processing equipment₄、AlCl₃And the like. When such a sublimable gas is sucked by the vacuum pump and flows through the flow path in the vacuum pump, the sublimable gas solidifies and accumulates on the inner wall surface of the flow path at a portion where the relationship between the pressure (partial pressure) and the temperature of the gas in the flow path shown by the vapor pressure curve is changed from a vapor phase to a solid phase. In particular, a significant accumulation occurs in a portion where the pressure is relatively high, such as the vicinity of the downstream of the flow path.

As a countermeasure for removing the products deposited as described above, conventionally, a vacuum pump has been heated by a belt heater or the like and a seed and heat retention mechanism has been used (for example, see patent document 1 or patent document 2).

However, according to the conventional method of heating a vacuum pump as described above and seeding and heat-insulating, structural parts in a vacuum pump such as a rotary body are also heated and seeded and heat-insulated at the same time. In particular, since the rotating body of the vacuum pump rotates at a high speed, if the rotating body continues to rotate in a state where the temperature exceeds the design allowable temperature of the material constituting the rotating body due to heating and soaking, there are problems such as breakage due to a decrease in the material strength of the rotating body, deformation due to creep deformation of the rotating body, contact between the deformed rotating body and a fixed part located on the outer periphery thereof, and breakage of the rotating body and the fixed part due to contact. Therefore, it cannot be said that the conventional method of heating the vacuum pump and seeding and heat-insulating is suitable for removing products accumulated in the flow path in the vacuum pump.

In addition, gases which are difficult to remove the deposited products by heating, seeding and heat preservation, for example, gases having a high sublimation temperature, may flow through the flow path in the vacuum pump. In this case, the products continue to deposit in the gas flow path formed between the rotating body and the fixed component located on the outer periphery in the vacuum pump, and the rotating body and the fixed component come into contact with each other via the deposited products, thereby causing a problem that the rotating body or the fixed component is damaged.

Patent document 1: japanese patent laid-open publication No. 2015-31153.

Patent document 2: japanese patent laid-open publication No. 2015-148151.

Disclosure of Invention

The present invention has been made to solve the above-described problems, and an object thereof is to provide a vacuum pump suitable for removing products accumulated in a flow path in the vacuum pump, and a fixture, an exhaust port, and a control mechanism used for the vacuum pump.

In order to achieve the above object, the present invention is a vacuum pump including a rotating body disposed in an outer casing, a support mechanism rotatably supporting the rotating body, a drive mechanism rotationally driving the rotating body, an air inlet for sucking air by rotation of the rotating body, an air outlet for discharging the air sucked from the air inlet, a gas flow path that is shifted from the air inlet to the air outlet, and a gas flow path that removes products accumulated on an inner wall surface of the flow path, wherein the removal mechanism is configured to: an injection hole having one end open is provided in an inner wall surface of the flow path, and a purge gas is injected into the flow path from the injection hole.

In the present invention, the exhaust gas treatment apparatus may further include a control device that functions as a device for controlling any one of the pressure, flow rate, and injection time of the purge gas.

In the present invention, a sensing means for sensing a supply state of the gas supply system may be provided in the middle of the gas supply system for supplying the removed gas to the ejection hole.

In the present invention, the control means may function as means for outputting a signal necessary for adjusting the supply pressure or the supply flow rate of the purge gas to the ejection hole based on the result of sensing by the sensing means.

In the present invention, the control means may function as: and a control unit for controlling the supply pressure and the supply flow rate of the purge gas to the injection hole, and outputting a signal necessary for adjusting the supply pressure and the supply flow rate of the purge gas to the injection hole or outputting a signal necessary for sounding an alarm when the estimated accumulation amount of the product exceeds a threshold value.

In the present invention, the control means may function as means for supplying the purge gas to the ejection hole based on a command from an external device.

In the present invention, the control of the injection timing may include at least one of a control of always injecting the purge gas from the injection hole and a control of intermittently injecting the purge gas from the injection hole.

In the present invention, the control of the flow rate may include at least one of a control of maintaining a constant flow rate of the purge gas injected from the injection hole and a control of increasing or decreasing the flow rate.

In the present invention, the pressure control may include at least one of a control of keeping a pressure of the removal gas injected from the injection hole constant and a control of supplying the removal gas injected from the injection hole so as to protrude from the injection hole.

In the present invention, the purge gas may be an inert gas.

In the present invention, the degassing gas may be a high-energy gas activated by an excitation mechanism.

In the present invention, the degassing gas may be a high-temperature gas heated by a heating means.

In the present invention, a plurality of the injection holes may be provided.

In the present invention, the inner wall surface of the flow path may be formed of a porous material, and the porous material may be used as the injection hole.

In the present invention, a part of the surface of the porous material constituting the inner wall surface of the flow path may be shielded, and a part other than the part may be configured as a non-shielding portion without shielding, whereby a gas can be ejected and removed from the pores of the porous material into the flow path within the range of the non-shielding portion.

In the present invention, a plate body having a surface area larger than an opening area of the injection hole may be provided in the vicinity of an opening end of the injection hole, and the plate body may be formed of a porous material, and a porous hole of the porous material may be used as the injection hole.

In the present invention, the flow path may be a flow path formed in a screw groove shape between an outer periphery of the rotary body and a fixed member facing the rotary body, and an inner wall surface in the vicinity of a downstream outlet of the flow path may be configured such that one end of the injection hole is open.

In the present invention, the flow path may be a flow path formed in a screw groove shape between an outer periphery of the rotary body and a fixed member facing the rotary body, and an inner wall surface in the vicinity of an upstream inlet of the flow path may be configured such that one end of the injection hole is open.

In the present invention, the flow path may be a flow path formed by a gap defined between a rotor blade provided on an outer peripheral surface of the rotor and a stationary blade positioned and fixed in the outer casing, and an inner wall surface of the flow path in the vicinity of a downstream outlet may be configured such that one end of the injection hole is open.

In the present invention, the flow path may include an exhaust port communicating with a downstream outlet of the flow path, and an inner wall surface of the exhaust port may have a structure in which one end of the injection hole is open.

In the present invention, the flow path may be a flow path formed by a gap defined between a rotor blade provided on an outer peripheral surface of the rotor and a fixed blade positioned and fixed in the outer casing, and the flow path may include an inner surface of a spacer for positioning and fixing the fixed blade, and an inner wall surface of the spacer may have a structure in which one end of the injection hole is opened.

In the present invention, the flow path may be a flow path formed by a gap defined between a rotor blade provided on an outer peripheral surface of the rotor and a stationary blade positioned and fixed in the outer casing, and an outer surface of the stationary blade may have a structure in which one end of the injection hole is opened.

In the present invention, the execution based on the command may include a process of outputting a maintenance request signal to the external device, and the process may output a signal necessary for supplying the purging gas when receiving a maintenance permission signal output from the external device based on the maintenance request signal.

In the present invention, the inner wall surface of the flow path may be coated with a material having higher non-adhesiveness or lower surface free energy than the constituent substrate of the flow path.

In the present invention, the material of the coating layer may be a coating material of a fluororesin or a fluorine-containing resin.

The present invention is a fixed component constituting a flow path of a vacuum pump including a rotating body disposed in an outer casing, a support mechanism rotatably supporting the rotating body, a drive mechanism rotatably driving the rotating body, an air inlet for sucking air by rotation of the rotating body, an air outlet for discharging the air sucked from the air inlet, and a flow path of the air transferred from the air inlet to the air outlet, wherein a jet hole having one end opened is provided on an inner wall surface of the fixed component as a removal mechanism for removing a product accumulated on the inner wall surface of the flow path.

The present invention is an exhaust port constituting an exhaust port of a vacuum pump including a rotating body, a support mechanism, a drive mechanism, an air inlet, an exhaust port, and a gas flow path, the rotating body being disposed in an outer casing, the support mechanism rotatably supporting the rotating body, the drive mechanism rotationally driving the rotating body, the air inlet being for sucking gas by rotation of the rotating body, the exhaust port being for discharging the gas sucked from the air inlet, the gas flow path being shifted from the air inlet to the exhaust port, the exhaust port being characterized in that a jet hole having one end opened is provided on an inner wall surface of the exhaust port as a removal mechanism for removing a product accumulated on the inner wall surface of the flow path.

The present invention is a control mechanism for a vacuum pump, the vacuum pump including a rotating body disposed in an outer casing, a support mechanism rotatably supporting the rotating body, a drive mechanism rotatably driving the rotating body, an air inlet for sucking air by rotation of the rotating body, an air outlet for discharging the air sucked from the air inlet, an exhaust port for transferring a flow path of the air from the air inlet to the exhaust port, a removal mechanism for removing a product accumulated on an inner wall surface of the flow path, the removal mechanism including an injection hole having one end opened in an inner wall surface of the flow path, the vacuum pump having a structure for injecting the removal air into the flow path from the injection hole, the apparatus is characterized in that the apparatus controls one of the pressure, flow rate and injection time of the removing gas injected from the injection hole into the flow path, outputs a signal necessary for adjusting the supply pressure or supply flow rate of the removing gas, functions as a means for outputting a signal necessary for sounding an alarm, or functions as a means for executing the supply of the removing gas to the injection hole based on a command from an external device.

Effects of the invention

In the present invention, as described above, as a specific configuration of the removing means for removing the product deposited on the inner wall surface of the flow path, the removing means has a structure in which the inner wall surface of the flow path is provided with an injection hole having one end opened and the removing gas is injected into the flow path from the injection hole. Therefore, since the product deposited on the inner wall surface of the flow passage is not heated and preserved by the conventional pump but is forcibly detached and removed by the physical force of the removal gas injected from the injection hole, defects (damage due to a decrease in material strength of the rotating body, deformation due to creep deformation of the rotating body, contact between the deformed rotating body and the fixed part located on the outer periphery thereof, damage of the rotating body and the fixed part due to contact, and the like) due to the conventional pump heating and preserving are not generated, and a vacuum pump suitable for removing the product deposited on the flow passage in the vacuum pump, and a fixed part, an exhaust port, and a control mechanism used therefor can be provided.

The "porous structure using the ejection hole as the porous material" in the present invention includes "a part of the porous structure using the ejection hole as the porous material" and "the entire porous structure using the ejection hole as the porous material". This is also true in the detailed description.

The "capable of ejecting a removing gas into the flow channel from the porous structure of the porous material" in the present invention includes "capable of ejecting a removing gas into the flow channel from a part of the porous structure of the porous material" and "capable of ejecting a removing gas into the flow channel from all the porous structures of the porous material". This is also true in the detailed description.

Drawings

Fig. 1 is a sectional view of a vacuum pump to which the present invention is applied (specific configuration examples (1) to (2) thereof) including a removal mechanism).

Fig. 2 is a schematic configuration diagram of an exhaust system of the vacuum pump of fig. 1 and an external device including an exhaust mechanism using the same as a gas.

Fig. 3 is an explanatory view of a specific structural example (4) of the removal mechanism, (a) is a plan view of a spacer to which the structural example (4) is applied, (b) is a side view in which a radial half range of the spacer is cut, and (c) is an enlarged view of the periphery of the 4 th ejection hole shown in (b).

Fig. 4 is an explanatory view of a specific structural example of the removing mechanism (5 thereof), (a) is a plan view (an exploded state before being assembled to a vacuum pump) of a plurality of fixed vanes to which the structure is applied, (b) is an enlarged view of a portion a in (a), (c) is a sectional view of D1 in (b), (D) is a sectional view of D2 in (b), and (e) is a structural view of an example in which the structural example of the removing mechanism in fig. 4 is combined with the structural example of the removing mechanism in fig. 3.

Fig. 5(a), (b) and (c) are cross-sectional views of the injection holes that can be used in the vacuum pump of fig. 1, and (d) is an explanatory diagram of a state in which the plurality of injection holes shown in fig. (c) are viewed from the front (the thread groove exhaust flow path side).

Fig. 6 is an explanatory view of a specific structure (porous material type) example 1 of the injection hole.

Fig. 7 is a cross-sectional view of D4 of fig. 6.

Fig. 8(a) is a sectional view of the vicinity of the exhaust port, and fig. (b) is a sectional view taken along line D5 in fig. (a).

Fig. 9 is an explanatory view of a specific structure (porous material type) example 2 of the injection hole.

Fig. 10 is an enlarged cross-sectional view of the thread groove exhaust stator shown in fig. 9.

Fig. 11 is an enlarged view of the vicinity of a portion a1 of fig. 10.

Fig. 12(a) and (b) are enlarged views of the vicinity of the portion a1 in fig. 10.

Fig. 13 is an explanatory diagram of an example in which the 4 th injection hole is formed with a porous material at a structure in which the spacer is provided with the 4 th injection hole.

Fig. 14(a) and (b) are explanatory views of an example in which the porous material for the 4 th injection hole is formed in a structure in which the fixed vane is provided with the 5 th injection hole, and (b) is an explanatory view of an example in which shielding is omitted in the structure in which the porous material for the fixed vane is formed.

Fig. 15 is an explanatory view of a specific structure (porous material type) example 3 of the injection hole.

Fig. 16 is an explanatory diagram of an example in which a porous plate injection structure is applied to a structure in which the thread groove exhaust section stator is provided with the 4 th injection hole.

FIG. 17 is an explanatory diagram of an example in which a porous plate injection structure is applied to a structure in which the fixed blades are provided with the 5 th injection holes.

Fig. 18 is a diagram for explaining the highlighted gas injection control.

Fig. 19 is a graph showing the relationship between the processing of the external device and the timing of the ejection of the removal gas.

Fig. 20 is an explanatory diagram of a change in pressure of the purge gas in a case where the ejection hole or the gas supply system is clogged due to deposition of the product.

Detailed Description

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a sectional view of a vacuum pump to which the present invention is applied, and fig. 2 is a schematic configuration diagram of an exhaust system of the vacuum pump of fig. 1 and an external device including an exhaust mechanism using the same as a gas.

Referring to fig. 1, a vacuum pump P1 in this figure includes a casing 1 having a cylindrical cross section, a rotor RT disposed in the casing 1, a support mechanism SP for rotatably supporting the rotor RT, a drive mechanism DR for rotationally driving the rotor RT, an intake port 2 for taking in gas by rotation of the rotor RT, an exhaust port 3 for discharging gas taken in from the intake port 2, a flow path R for gas transferred from the intake port 2 to the exhaust port 3, and a removal mechanism RM for removing products accumulated on an inner wall surface of the flow path R.

The outer case 1 is a bottomed cylindrical shape in which a cylindrical pump case 1A and a bottomed cylindrical pump mount 1B are integrally connected in the cylinder axial direction by fastening bolts, and the upper end side of the pump case 1A is open as the intake port 2.

Further, the following is made: an exhaust port EX is provided on a side surface of a lower end portion of the pump mount 1B, one end of the exhaust port EX communicates with the flow passage R, and the other end of the exhaust port EX opens as the exhaust port 3.

Referring to fig. 2, the inlet 2 is connected to a vacuum chamber having a high vacuum such as a device M (hereinafter referred to as an "external device M") that performs a predetermined process in a vacuum atmosphere, for example, a process chamber of a semiconductor manufacturing apparatus. The exhaust port 3 is connected in communication with an auxiliary pump P2.

As shown in fig. 1, a cylindrical stator pole 4 for housing various electric components is provided at the center of the pump housing 1A. In the vacuum pump P1 shown in fig. 1, the stator pole 4 is formed as a component other than the pump mount 1B, and the stator pole 4 is erected on the pump mount 1B by screwing and fixing the stator pole 4 to the inner bottom of the pump mount 1B, but the stator pole 4 may be erected integrally on the inner bottom of the pump mount 1B as another embodiment.

The aforementioned rotating body RT is provided outside the stator pole 4. The rotor RT is enclosed in the pump housing 1A and the pump base 1B, and has a cylindrical shape surrounding the outer periphery of the stator pole 4.

A rotary shaft 5 is provided inside the stator pole 4. The rotary shaft 5 is disposed such that its upper end faces the suction port 2 and its lower end faces the pump mount 1B. Further, the rotary shaft 5 is rotatably supported by magnetic bearings (specifically, two sets of radial magnetic bearings MB1 and one set of axial magnetic bearings MB2, which are well known). Further, a drive motor MO is provided inside the stator pole 4, and the rotary shaft 5 is rotationally driven around the axis thereof by the drive motor MO.

The upper end of the rotating shaft 5 protrudes upward from the cylindrical upper end surface of the stator pole 4, and the upper end side of the rotating body RT is integrally fixed to the protruding upper end of the rotating shaft 5 by a fastening mechanism such as a bolt. That is, the rotary body RT is rotatably supported by magnetic bearings (a radial magnetic bearing MB1 and an axial magnetic bearing MB2) via the rotary shaft 5, and in this supported state, when the drive motor MO is started, the rotary body RT can rotate around its axial center integrally with the rotary shaft 5. In short, in the vacuum pump P1 of fig. 1, the rotary shaft 5 and the magnetic bearing function as a support mechanism for rotatably supporting the rotary body RT, and the drive motor MO functions as a drive mechanism for rotationally driving the rotary body RT.

The vacuum pump P1 in fig. 1 includes a plurality of vane exhaust stages PT that function as means for discharging gas molecules from the inlet port 2 to the outlet port 3.

In the vacuum pump P1 of fig. 1, a screw-groove pump stage PS is provided between a downstream portion of the plurality of vane exhaust stages PT, specifically, between the vane exhaust stage PT (ptn) at the lowest stage of the plurality of vane exhaust stages PT and the exhaust port 3.

Details of the wing exhaust stage PT

The vacuum pump P1 in fig. 1 functions as a plurality of blade exhaust stages PT upstream of the rotor RT from substantially the middle thereof. The plurality of vane exhaust stages PT will be described in detail below.

A plurality of rotary blades 6 that rotate integrally with the rotor RT are provided on the outer peripheral surface of the rotor RT on the upstream side of the substantial middle of the rotor RT, and these rotary blades 6 are radially arranged at predetermined intervals about the rotation center axis of the rotor RT (specifically, the axis of the rotary shaft 5) or the axis of the outer casing 1 (hereinafter, referred to as "vacuum pump axis") with respect to the vane exhaust stages PT (PT1, PT2, … PTn).

On the other hand, a plurality of fixed vanes 7 are positioned and fixed in the outer casing 1 (specifically, on the inner peripheral side of the pump casing 1A), and these fixed vanes 7 are also disposed at predetermined intervals radially about the vacuum pump axial center with respect to the vane exhaust stages PT (PT1, PT2, … PTn) similarly to the rotary vanes 6.

That is, each of the vane stages PT (PT1, PT2, … PTn) is provided in a plurality of stages between the intake port 2 and the exhaust port 3, and the vane stages PT (PT1, PT2, … PTn) includes a plurality of rotary vanes 6 and fixed vanes 7 radially arranged at predetermined intervals, and the rotary vanes 6 and the fixed vanes 7 form a structure for discharging gas molecules.

Each of the rotary blades 6 is a blade-shaped cut product formed by cutting integrally with the outer diameter processed portion of the rotary body RT, and is inclined at an angle most suitable for the exhaust of gas molecules. Furthermore, each fixed vane 7 is also inclined at an angle most suitable for the exhaust of gas molecules.

In the vacuum pump P1 of fig. 1, as a specific structure of the thread groove exhaust stator 8, a component (threaded spacer) is used in which the spacer S is provided to protrude from the upper end portion thereof, and the plurality of fixed blades 7 are positioned and fixed by having the outer peripheral portions of the fixed blades 7 between the spacers S in a state where the plurality of spacers S are stacked in multiple stages in the pump axial direction from the threaded spacer, but the positioning and fixing of the fixed blades 7 by the spacer S is not limited to this structure.

Description of the exhaust operation of multiple vane exhaust stages PT

Among the plurality of vane stages PT configured as described above, the plurality of rotary blades 6 rotate at high speed integrally with the rotary shaft 5 and the rotary body RT due to the activation of the drive motor MO in the uppermost vane stage PT (PT1), and a downward and tangential momentum is imparted to the gas molecules entering from the inlet port 2 by the inclined surface of the rotary blade 6 facing the front surface in the rotation direction and downward (direction from the inlet port 2 toward the outlet port 3, hereinafter simply referred to as downward). The gas molecules having such downward momentum are sent to the next vane exhaust stage PT (PT2) by the rotating blades 6 provided on the fixed blades 7 and the downward inclined surface facing the opposite direction of rotation.

In the next and subsequent vane stages PT (PT2), the rotary vane 6 rotates in the same manner as the uppermost vane stage PT (PT1), and the momentum imparted to the gas molecules by the rotary vane 6 and the feeding operation of the gas molecules by the fixed vane 7 are performed as described above, whereby the gas molecules in the vicinity of the inlet port 2 are discharged so as to sequentially migrate downstream of the rotary body RT.

As is known from the above-described exhaust operation of gas molecules at the plurality of vane exhaust stages PT, the gaps set between the rotary blades 6 and the stationary blades 7 at the plurality of vane exhaust stages PT serve as flow paths for discharging gas (hereinafter referred to as "inter-blade exhaust flow paths R1"). The inter-blade exhaust flow path R1 includes, as its inner wall surface structure, the inner surface of the spacer S (the surface facing the outer periphery of the rotor RT) for positioning and fixing the fixed blade 6, in addition to the outer surfaces of the rotor blade 6 and the fixed blade 7.

Details of the screw-groove Pump stage PS

The vacuum pump P1 in fig. 1 is configured to function as a screw groove pump stage PS downstream of the rotor RT from substantially the middle thereof. The thread groove pump stage PS is described in detail below.

The thread groove pumping stage PS is a mechanism for forming a thread groove exhaust passage R2 on the outer peripheral side of the rotary body RT (specifically, the outer peripheral side of the rotary body RT portion downstream from the substantial middle of the rotary body RT), and includes a thread groove exhaust stator 8, and the thread groove exhaust stator 8 is attached to the inner peripheral side of the outer casing 1 as a fixed component of the vacuum pump.

The thread groove exhaust section stator 8 is a cylindrical fixed member disposed so that the inner peripheral surface thereof faces the outer peripheral surface of the rotating body RT, and is disposed so as to surround the portion of the rotating body RT located downstream from the substantial middle of the rotating body RT.

The portion of the rotor RT located downstream of the substantially middle of the rotor RT is a portion where the rotating element as the thread groove exhaust portion PS rotates, and is inserted and seeded into the inside of the thread groove exhaust portion stator 8 through a predetermined gap.

A thread groove 81 having a tapered shape with a depth decreasing downward is formed in the inner peripheral portion of the thread groove exhaust section stator 8. The thread groove 81 is engraved spirally from the upper end to the lower end of the thread groove exhaust section stator 8.

A thread groove exhaust passage R2 for discharging gas is formed on the outer peripheral side of the rotary body RT by the thread groove exhaust unit stator 8 including the thread groove 81 as described above. Although not shown, the thread groove 81 described above may be formed on the outer peripheral surface of the rotary body RT, thereby providing the thread groove exhaust passage R2 as described above.

In the screw groove pump stage PS, since the gas is transferred while being compressed by the drag effect between the screw groove 81 and the outer peripheral surface of the rotary body RT, the depth of the screw groove 81 is set to be deepest on the upstream inlet side (the flow path opening end near the inlet port 2) of the screw groove exhaust flow path R2 and shallowest on the downstream outlet side (the flow path opening end near the exhaust port 3).

The inlet (upstream opening end) of the screw-groove exhaust flow path R2 opens to the outlet of the inter-blade exhaust flow path R1 described earlier, specifically, to a gap (hereinafter referred to as "final gap GE") between the fixed blade 7E and the screw-groove exhaust stator 8 constituting the lowermost vane exhaust stage PTn, and the outlet (downstream opening end) of the screw-groove exhaust flow path R2 communicates with the exhaust port 3 through the pump internal exhaust port side flow path R3.

The pump inner exhaust port side flow path R3 is formed so as to communicate with the exhaust port 3 from the outlet of the screw-groove exhaust flow path R2 by providing a predetermined gap (gap in the vacuum pump P1 of fig. 1 such that it makes one turn around the lower outer periphery of the stator post 4) between the rotary body RT, the lower end portion of the screw-groove exhaust stator 8, and the inner bottom portion of the pump mount 1B.

Description of the exhaust action at the screw-groove Pump stage PS

The gas molecules that reach the final gap GE (the outlet of the inter-blade exhaust passage R1) by the transfer based on the exhaust action at the plurality of blade exhaust stages PT described above are transferred to the thread groove exhaust passage R. The transferred gas molecules are transferred to the pump inner discharge port side flow path R3 while being compressed from the transfer flow to a viscous flow by the drag effect generated by the rotation of the rotating body RT. The gas molecules that have reached the pump inner exhaust port side flow path R3 flow into the exhaust port 3, pass through an auxiliary pump, not shown, and are discharged outside the housing case 1.

Description of gas channel R

As is clear from the above description, the vacuum pump P1 of fig. 1 includes a gas flow path R including the inter-blade exhaust flow path R1, the final gap GE, the screw groove exhaust flow path R2, and the pump interior exhaust port side flow path R3, and the gas is transferred from the intake port 2 to the exhaust port 3 through the gas flow path R.

In the vacuum pump P of fig. 1, the inner wall surface of the flow path R (specifically, the inner wall surface of the screw groove exhaust flow path R2) is coated with a material having higher non-adhesiveness or lower surface free energy than the constituent substrate of the flow path R.

Thus, even if the product is deposited on the inner wall surface of the flow path R, the deposited product is in a state of being relatively easily peeled off. Further, a coating material of fluororesin or fluororesin can be used as a material of the coating layer, but the invention is not limited thereto.

Description of removal mechanism RM

In the vacuum pump P1 of fig. 1, the removal mechanism RM includes ejection holes 91, 92, and 93 having one end opened in the inner wall surface of the flow path R, and is configured to eject the removal gas from the ejection holes 91, 92, and 93 into the flow path R.

Concrete structural example of removal mechanism RM (1 thereof)

In the vacuum pump P1 shown in fig. 1, one end of the 1 st injection hole 91 is open to the inner wall surface (except the inner wall surface of an exhaust port EX described later) in the vicinity of the downstream outlet of the screw-groove exhaust passage R2, which is a screw-groove-shaped passage formed between the outer periphery of the rotating body RT and the screw-groove exhaust unit stator 8 (stationary component) facing the rotating body RT.

The pressure near the downstream outlet of the spiral groove exhaust flow path R2 is high, and the state of the flowing gas moves from the gas phase to the solid phase region, so that the deposition of the product is likely to occur. However, the deposited product is forcibly peeled off by the physical force of the removing gas injected from the 1 st injection hole 91, and is removed.

Concrete structural example of removal mechanism RM (2 thereof)

In the vacuum pump P1 of fig. 1, one end of the 2 nd injection hole 92 is open on the inner wall surface in the vicinity of the upstream inlet of the screw groove exhaust passage R2.

As described above, the upstream inlet of the thread groove exhaust flow path R2 opens into the final gap GE so as to intersect with the inter-blade exhaust flow path R1, and the flow of the exhaust gas molecules changes greatly in the final gap GE and in the vicinity of the upstream inlet of the thread groove exhaust flow path R2, so that a region where the flow velocity of the exhaust gas decreases (hereinafter referred to as "exhaust gas stagnation region") is likely to occur, and it is also found from the experimental results of the present inventors that the product is likely to accumulate in such an exhaust gas stagnation region.

The product accumulated in the exhaust gas stagnation region as described above is forcibly peeled off by the physical force of the purge gas injected from the 2 nd injection hole 92, and is removed.

Concrete structural example of removal mechanism RM (3 thereof)

The flow path R of the vacuum pump P in fig. 1 includes the exhaust port EX described above that communicates with the downstream outlet of the flow path R, and in the vacuum pump P in fig. 1, one end of the 3 rd injection hole 93 is open on the inner wall surface of the exhaust port EX.

Since the exhaust port EX is located downstream of the vicinity of the downstream outlet of the screw groove exhaust passage R2, the pressure is higher and product accumulation is likely to occur. However, the deposited product is forcibly peeled off by the physical force of the removing gas injected from the 3 rd injection hole 93, and is removed.

Concrete structural example of removal mechanism RM (4 thereof)

Fig. 3 is an explanatory view of a specific structural example (4) except for the mechanism RM, in which (a) is a plan view of a spacer to which the structural example (4) is applied, (b) is a side view of the spacer cut across a radial half range thereof, and (c) is an enlarged view of the 4 th ejection hole periphery shown in (b).

In the structural example of fig. 3 (4), the following structure is adopted: the 4 th injection hole 94 is provided in the spacer S (see fig. 1) described above, and one end of the 4 th injection hole 94 opens in an inner surface of the spacer S (specifically, a surface facing the outer peripheral surface of the rotating body RT). In the structural example of fig. 3 (4) described above, the structure in which the removal gas supply passage 11D is provided in the vicinity of the 4 th ejection hole 94 and the structure in which the other end of the 4 th ejection hole 94 is open to the removal gas supply passage 11D are adopted.

Concrete structural example of removal mechanism RM (5 thereof)

Fig. 4 is an explanatory view of a specific structural example (5) of the mechanism RM, where (a) is a plan view (an exploded state before assembling the vacuum pump) of the plurality of fixed vanes 7 to which the structure is applied, (b) is an enlarged view of a portion a in (a), (c) is a sectional view of D1 in (b), and (D) is a sectional view of D2 in (b). (a) A plan view of the plurality of fixed vanes 7 to which this structure is applied (an exploded state before assembly of the vacuum pump), (b) is a sectional view taken along line D1 in (a), (c) is a sectional view taken along line D2 in (b), and (e) is a structural diagram of an example in which the structural example of the removal mechanism in fig. 4 is combined with the structural example of the removal mechanism in fig. 3.

In the structural example of fig. 4 (5), the following structure is adopted: the 5 th injection hole 95 is provided in the fixed vane 7 (see fig. 1) described above, and one end of the 5 th injection hole 95 opens in the outer surface of the fixed vane 7 (see fig. 5 d). In the structural example of fig. 4 (5 thereof), the structure in which the removal gas supply passage 11E is provided in the vicinity of the 5 th ejection hole 95 and the structure in which the other end of the 5 th ejection hole 95 is open to the removal gas supply passage 11E are also adopted.

In fig. 4E, gas introduction ports (ports) to the removal gas supply passages 11D and 11E are provided, respectively, but a gap (not shown) may be provided between the spacer S and the pump housing 1A to supply gas from one gas introduction port to the plurality of removal gas supply passages 11D and 11E.

Concrete examples of injection holes (non-porous material type)

The 1 st to 5 th injection holes 91, 92, 93, 94, and 95 can be formed by machining such as hole machining by a drill or groove machining by an end mill if they are formed from a material that can be machined, such as a solid material (e.g., the thread groove exhaust section stator 8, the ring member on the outer peripheral surface of the exhaust port EX, the spacer S, and the fixed blade 7), or a casting, as the parts provided with them.

The 1 st and 2 nd injection holes 91 and 92, and the 4 th and 5 th injection holes can be provided in plural numbers in the circumferential direction of the rotating body RT, and the 3 rd injection hole 93 can be provided in plural numbers in the circumferential direction of the exhaust port EX. In these cases, the injection holes 91, 92, and 93 are arranged at equal intervals or are arranged at concentrated locations where products are particularly likely to accumulate, and the arrangement positions thereof can be changed as needed.

In the vacuum pump P1 of fig. 1, a plurality of the 1 st ejection holes 91 are provided in the circumferential direction of the rotating body RT, the removal gas supply passage 11A is provided in the vicinity of the 1 st ejection holes 91, and the other end of the 1 st ejection holes 91 is open to the removal gas supply passage 11A. With this configuration, the stripping gas can be simultaneously injected from all the 1 st injection holes 91 by supplying the stripping gas to only one stripping gas supply passage 11A.

In the vacuum pump P1 of fig. 1, a plurality of the 2 nd ejection holes 92 are provided in the circumferential direction of the rotating body RT, the purge gas supply passage 11B is provided in the vicinity of the 2 nd ejection holes 92, and the other end of the 2 nd ejection holes 92 is open to the purge gas supply passage 11B. With this configuration, the purge gas can be supplied to only one purge gas supply passage 11B, and the 2 nd ejection holes 92 can simultaneously eject the purge gas.

As a specific example of the structure of the removal gas supply passages 11A and 11B, the vacuum pump P1 in fig. 1 has a structure in which the removal gas supply passages 11A and 11B are formed by grooves provided in the circumferential direction on the outer peripheral surface of the screw-groove exhaust stator 8 and the inner surface of the outer case 1, but is not limited to this structure.

Further, in the vacuum pump of fig. 1, a configuration is adopted in which a plurality of the 3 rd ejection holes 93 are provided along the circumferential direction of the exhaust port EX, a configuration is adopted in which the scavenging gas supply passage 11C is provided in the vicinity of the 3 rd ejection holes 93, and a configuration is adopted in which the other end of the 3 rd ejection holes 93 is opened with respect to the scavenging gas supply passage 11C, and as a specific structural example of the scavenging gas supply passage 11C, a configuration is adopted in which a ring member is fitted to the outer circumferential surface of the exhaust port EX, and the scavenging gas supply passage 11C is formed by a groove in the inner surface of the fitted ring member and the outer circumferential surface of the exhaust port EX, but the.

The 1 st injection hole 91 may be formed to intersect the flow path R at a substantially right angle as shown in fig. 5(a), or may intersect the flow path R at an inclination as shown in fig. (b). This is also the same for the 2 nd, 3 rd, 4 th and 5 th injection holes 92, 93, 94 and 95. As shown in fig. (c), the 1 st injection hole 91 can be provided in plural in the pump axial direction. This is also the same for the 2 nd and 4 th injection holes 92 and 94. Although not shown, a plurality of the 3 rd injection holes 93 may be provided in the axial direction of the exhaust port EX, and a plurality of the 5 th injection holes 95 may be provided in the pump radial direction or the longitudinal direction of the stationary blades 7.

Further, when the 1 st injection hole 91 is provided in plural as described above, the injection holes 91 may be arranged in a matrix in a circular region as shown in fig. 5 (d). This is also true of the other injection holes 92, 93, 94, 95.

Brief description of specific Structure of injection hole (porous Material type)

Since the components forming the inner wall surface of the flow path described above (specifically, the screw groove exhaust section stator 8, the ring member on the outer peripheral surface of the exhaust port EX, the spacer S, the stationary blade 7, and the like) are generally formed of a solid material or a cast material, the inner wall surface of the flow path is formed of the same material as the components, that is, the solid material or the cast material, but in this specific structural example (1) of the injection hole, the inner wall surface of such a flow path is formed of a porous material, and the porous material is used as the injection hole.

As the porous material forming the inner wall surface of the flow path, for example, a non-metal material such as ceramic, resin (plastic), or the like is considered in addition to a metal material such as aluminum, stainless steel, iron, or the like, but the present invention is not limited thereto.

As a method for forming the porous material, a method of firing and forming a metal powder (powder metallurgy), a method of solidifying a powder via a binder (press forming), a method of forming a porous coating film by colliding a material heated on the surface of a base material to be made porous at high speed (thermal spraying), a method of forming a porous coating film by 3D printing, and the like are conceivable, but the method is not limited thereto.

Concrete Structure of injection hole (porous Material type) example 1

Fig. 6 is an explanatory view of a specific structure (porous material type) example 1 of the injection hole, fig. 7 is a sectional view taken along direction D4 in fig. 6, fig. 8(a) is a sectional view taken near the exhaust port, and fig. (b) is a sectional view taken along direction D5 in fig. (a).

In the structure (porous formula) example 1 of fig. 6, by replacing a part of the screw groove exhaust section stator 8 (specifically, the vicinity of the 1 st injection hole 91 of fig. 1 and the vicinity of the 2 nd injection hole 92 of fig. 1 described earlier) with a porous material for the porous section PP, the inner wall surface of the flow path (specifically, the downstream end of the screw groove exhaust flow path R2 and the upstream end of the screw groove exhaust flow path R communicating with the final gap GE) is made of the porous material, and the removal gas can be injected into the flow path from the pores of the porous material.

In the structure (porous formula) example 1 of fig. 6, a part of the exhaust port EX (specifically, the vicinity of the 3 rd injection hole 92 of fig. 1 described earlier) is replaced with a porous material as the porous portion PP, and the inner wall surface of the flow path (specifically, the exhaust port EX) is made of the porous material, and the gas can be injected and removed from the pores of the porous material into the flow path.

When a part of the exhaust port EX is the porous part PP as described above, for example, as shown in fig. 7, a plurality of the porous parts PP may be arranged at a predetermined pitch in the circumferential direction of the exhaust port EX.

As a method of forming the inner wall surface of the exhaust port EX by a porous material, for example, as shown in fig. 8, a cylindrical porous tube EX1 made of a porous material may be fitted inside the exhaust port EX. In fig. 8, the entire length of the porous tube EX1 is set to be substantially the same as the entire length of the exhaust port EX, and the entire inner wall surface of the exhaust port is made of a porous material. The length of the porous tube EX1 can be changed as appropriate over the entire length of the exhaust port EX.

Concrete Structure of injection hole (porous Material type) example 2

Fig. 9 is an explanatory view of a specific structure (porous material type) example 2 of the injection hole, fig. 10 is a sectional view of a screw groove exhaust section stator to which the structure (porous material type) example 2 of fig. 9 is applied, and fig. 11 and fig. 12(a) and (b) are enlarged views of the vicinity of a portion a1 of fig. 10.

In the structure (porous material formula) example 1 of fig. 9, the entire screw groove exhaust section stator 8 is made of a porous material, and the inner wall surface of the flow path (specifically, the screw groove exhaust flow path R2) is made of a porous material, and a structure (hereinafter, referred to as a "porous shielding structure") is configured such that a part of the surface of the porous material constituting the inner wall surface is shielded by a shielding member U1 (see fig. 11, 12(a) and (b)) and a non-shielding section U2 (see fig. 11, 12(a) and (b)) other than the part is not shielded, whereby the injection site is locked and gas can be injected and removed from the pores of the porous material into the flow path in the range of the non-shielding section U2.

In the above-described porous shielding structure, the entire screw groove exhaust section stator 8 is formed of a porous material, but only a portion of the inner wall surface of the screw groove exhaust passage R2 in the entire screw groove exhaust section stator 8 may be formed of a porous material.

In the structure (porous material type) example 1 of fig. 9, the upward surface of the screw groove 81 constituting the inner wall surface of the screw groove exhaust flow path R2 (flow path) is formed as the non-blocked portion U2 as shown in fig. 11, the vicinity of the corner of the screw groove 81 is formed as the non-blocked portion U2 as shown in fig. 12(a), or the vicinity of the corner of the screw groove 81 and the crest of the screw groove 81 are formed as the non-blocked portion U2 as shown in fig. 12(b), but the present invention is not limited thereto. Which part of the screw groove exhaust passage R2 (passage) is configured as the non-blocked portion U2 can be changed as appropriate in consideration of the location where products are likely to accumulate.

However, it is difficult to form the injection hole in the wall surface or the corner of the thread groove 81 by machining such as hole machining by a drill or groove machining by an end mill. On the other hand, it is relatively easy to shield the parts other than the wall surface and the corner with the shielding member U1 without machining. Therefore, as described above, the structure in which the gas can be ejected and removed from the porous material in the flow path in the range of the non-shielding portion U2 (hereinafter referred to as "non-shielding portion ejection structure") has an advantage that it can be applied even in a narrow place where machining is difficult.

The porous shielding structure and the non-shielding portion injection structure described above can be applied to not only the 1 st injection hole 91 but also the 2 nd, 3 rd injection holes 92, 93, 4 th, 5 th injection holes 94, 95.

Fig. 13 shows an example in which the 4 th injection hole 94 is formed by porous material in the structure in which the spacer S is provided with the 4 th injection hole 94, and fig. 14(a) and (b) show an example in which the 4 th injection hole 95 is formed by porous material in the structure in which the fixed vane 7 is provided with the 5 th injection hole 95. In both of these examples, the porous shielding structure described above is employed, and the injection site is locked, so that the gas can be injected and removed from the porous pores of the porous material into the flow path in the range of the non-shielding portion U2.

Specifically, in the example of fig. 13, the inner surface of the spacer S constituting the flow path (inter-blade exhaust flow path R1) is configured as the non-shielding portion U2, and the removal gas is set to be ejected only from the inner surface of the spacer S. In the example of fig. 14 a and b, the vicinity of the downstream corner of the fixed vane 7 (see fig. 14 a) or a part of the downstream side of the fixed vane 7 (see fig. 14 b) or all of them (not shown) constituting the flow path (inter-vane exhaust flow path R1) is configured as the non-shielding portion U2, and thus the gas is injected and removed only from the vicinity of the downstream corner of the fixed vane 7 or from the downstream side to the lower surface.

As shown in fig. 14(c), the entire stationary blade 7 is made of a porous material, and the above-described shielding can be omitted, and in this case, the gas can be ejected and removed from any surface of the stationary blade 7.

Concrete Structure of injection hole (porous Material type) example 2

Fig. 15 is an explanatory view of a specific structure (porous material type) example 3 of the injection hole.

In the structure (porous material type) example 3 of fig. 15, a plate body P L having a surface area larger than the opening area thereof is provided in the vicinity of the open end of the 1 st injection hole 91 (see fig. 1) described earlier, and the plate body P L is formed of a porous material, and a porous structure of the porous material is used as the injection hole, and with such a structure (hereinafter referred to as a "porous plate injection structure"), the area capable of injecting gas is enlarged in the structure (porous material type) example 3 of fig. 15.

The porous plate injection structure described above can be applied not only to the 1 st injection hole 91 but also to the 2 nd and 3 rd injection holes 92 and 93 and the 4 th and 5 th injection holes, fig. 16 shows an example in which the porous plate injection structure described above is applied to a structure in which the 4 th injection hole 94 is provided in the thread-groove exhaust section stator 8, and fig. 17 shows an example in which the porous plate injection structure described above is applied to a structure in which the 5 th injection hole 95 is provided in the stationary vane 7, that is, in these examples, the plate body P L made of the porous material described above is provided in the vicinity of the open ends of the injection holes 94 and 95, and the porous holes of the porous material are used as the injection holes.

Description of gas to be ejected from gas ejection holes

In the vacuum pump P1 of fig. 1, as the purging gas to be injected from the gas injection holes 91, 92, 93, an inert gas, a high-temperature gas heated by a heating mechanism, or a high-energy gas activated by an excitation mechanism (for example, a gas plasmatized or excited by a plasma generation device) can be used. These degassing gases can be appropriately selected or used in combination as necessary.

The inert gas is nitrogen or a rare gas (argon, krypton, xenon, or the like), and when there is a risk that the sparging gas reacts with the process gas and is explosive or toxic, it is preferable to use a gas lacking such reactivity. Further, when a gas having a large molecular weight is used, the kinetic energy of the injected gas becomes large, and therefore a high removal effect is obtained.

Since the high-energy gas and the high-temperature gas have higher energy densities than the normal-temperature gas, the effect of removing the products deposited on the inner surface of the flow path R is high due to the injection from the gas injection holes 91, 92, and 93.

Description of control mechanism CX

The vacuum pump P shown in fig. 1 includes a control means CX for controlling the start and restart thereof, the support control of the rotary body RT by the magnetic bearings MB1 and MB2, the rotation speed control or the rotational speed control of the rotary body RT by the drive motor MO, and the like, and integrally controls the entire vacuum pump P.

As a specific configuration example of such a control means CX, the control means CX is configured by a numerical arithmetic processing device composed of hardware resources such as a Central Processing Unit (CPU), a Read Only Memory (ROM), a Random Access Memory (RAM), an input/output (I/O) interface, and the like in the vacuum pump P of fig. 1, for example, but is not limited to this configuration.

The control means CX functions not only as means for performing the overall control of the vacuum pump P as described above, but also as means for supplying gas to the ejection holes 91, 92, and 93 based on a command (specifically, a maintenance permission signal) from the external device M.

In this case, the external device M may periodically output the command (specifically, the maintenance permission signal). In order to prevent the operation of the external device M from being affected, the command output from the external device M is preferably output at a timing that does not affect the operation of the vacuum degree of the external device M, such as during the processing performed by the external device M, during the idle period of the processing, the work replacement period, or the maintenance period of the vacuum pump P1, as shown in fig. 19.

The command (specifically, the maintenance permission signal) may be added with information on the gas to be injected, such as what kind of gas is injected from the injection holes 91, 92, and 93 in what control system.

As shown in fig. 2, the execution of the control means CX may be configured to include a process of outputting the maintenance request signal RQ to the external device M, and a process of outputting a signal necessary for supplying the gas to the ejection holes 91, 92, 93 when receiving the command (specifically, the maintenance permission signal EN) output from the external device M based on the maintenance request signal RQ.

The maintenance request signal RQ can be output to the external device M via an input/output (I/O) interface of the control means CX, and the maintenance permission signal RQ can also be received via an input/output (I/O) interface of the control means CX.

The signals, that is, signals necessary for supplying the gas to the injection holes 91, 92, and 93 may be output to valves B L1, B L2, B L3, and B L4, which will be described later, via input/output (I/O) interfaces.

Description of gas injection control method in control mechanism CX

The control means CX can be configured to function as means for controlling any of the pressure, flow rate, and injection time of the removal gas to be injected from the injection holes 91, 92, and 93 as an injection control method of the removal gas.

The control means CX may be configured to function as means for controlling all of the control targets (pressure, flow rate, injection time) described above, or may be configured to function as means for controlling any two control targets (pressure and flow rate, pressure and injection time, flow rate and injection time).

The control of the injection time by the control means CX may be configured to include at least one of a control of constantly injecting the removing gas from the injection holes 91, 92, and 93 and a control of intermittently injecting the removing gas from the injection holes 91, 92, and 93 (hereinafter referred to as "intermittent injection control").

The control of the flow rate by the control means CX may be configured to include at least one of a control of maintaining a constant flow rate of the removal gas injected from the injection holes 91, 92, and 93 and a control of increasing or decreasing the flow rate.

The control of the pressure by the control means CX may be configured to include at least one of a control of maintaining a constant pressure of the removal gas injected from the injection holes 91, 92, and 93 and a control of supplying the removal gas injected from the injection holes 91, 92, and 93 so as to protrude from the injection holes (hereinafter referred to as "protruding gas injection control").

The control of the injection time, flow rate, and pressure by the control means CX described above can be realized by providing the valves B L1 and B L2 in the middle of the gas supply system SS for supplying the purge gas to the injection holes 91, 92, and 93, and controlling the valve B L2 by the control means CX, as shown in fig. 2, for example.

In the projected gas injection control, for example, as shown in fig. 18, a buffer tank TK in which the purge gas is temporarily stored may be provided in the middle of the gas supply system SP, and the purge gas may be released from the buffer tank TK to the injection holes 91, 92, and 93 at once by opening a valve B L4 located upstream of the buffer tank TK.

In the control means CX, a control method of continuously ejecting the purge gas from the ejection holes 91, 92, and 93 may be employed, but in order to minimize the influence on the processing of the external device M, it is preferable to output a maintenance request signal to the external device M as described above, and to eject the purge gas from the ejection holes 91, 92, and 93 only when a command (specifically, a maintenance permission signal) from the external device M is received.

Example of Combined use of sensing mechanisms in control mechanism CX

Referring to fig. 2, in the vacuum pump P1 of fig. 1, a sensing means MM for sensing the supply state of the gas supply system SS is provided in the middle of the gas supply system SS for supplying the degassing gas to the ejection holes 91, 92, 93. As such a sensing means MM, a measuring means, such as a known pressure gauge or flow meter, which numerically measures the supply state (specifically, pressure or flow rate) of the gas supply system SP can be used.

When the sensing means MM is used in the vacuum pump P1 of fig. 1, the control means CX is configured to function as means for outputting a signal necessary for adjusting the supply pressure or the supply flow rate of the purge gas to the ejection holes 91, 92, 93 based on the sensing result of the sensing means MM.

As a specific configuration for realizing this function, the following "configuration example 1" to "configuration example 3" can be adopted. The following structural examples 1 to 3 may be individually implemented or may be used in combination.

Principle of estimation of amount of accumulation of product

When clogging occurs in the injection holes 91, 92, 93 or the gas supply system SS due to accumulation of the product, the measurement value (pressure) of the sensing means MM (pressure gauge) rises to a high level (see fig. 20), and therefore the control means CX can estimate the amount of accumulation of the product by monitoring the change in the measurement value (pressure) at the sensing means MM.

Further, since the measured value (flow rate) of the sensing means MM (flow meter) decreases when the clogging occurs, the control means CX can estimate the amount of accumulation of the product by monitoring the change in the measured value (flow rate) of the sensing means MM.

Further, as shown in fig. 20, the control means CX may grasp the clogging level of the gas supply system SS and the deposition level of the product based on the measurement values (pressure and flow rate) measured by the measurement means MM (pressure gauge, flow meter) after a predetermined time (t1) has elapsed from the injection start time (t0) of the purge gas from the injection holes 91, 92, 93.

EXAMPLE 1 Structure example

Seeding as the measuring mechanism MM employs a pressure gauge.

The seeding control mechanism CX employs a process of receiving the measurement value (pressure) of the pressure gauge via the input/output (I/O) interface described above, a process of determining whether the received measurement value (pressure) has crossed a threshold value (for example, a warning level shown in fig. 20) by the cpu, and a process of outputting a predetermined signal to the valve B L2 via the input/output (I/O) interface to increase the supply pressure of the purge gas to the injection holes 91, 92, 93 when it is determined that the threshold value has been crossed in this determination process.

Example of construction 2

Harvesting and seeding as a measuring mechanism MM adopts a flowmeter.

The seeding control mechanism CX employs a process of receiving the measurement value (flow rate) of the flow meter via the input/output (I/O) interface, a process of determining whether the received measurement value (flow rate) is lower than a threshold value by the cpu, and a process of outputting a predetermined signal to the valve B L2 via the input/output (I/O) interface to increase the supply flow rate of the purge gas to the injection holes 91, 92, 93 or increase the supply pressure when it is determined that the received measurement value (flow rate) is lower than the threshold value in the determination process.

EXAMPLE 3 Structure example

Seeding as the measuring mechanism MM employs a pressure gauge.

As for the seed control mechanism CX, a process of constantly or periodically monitoring a change in the measured value (pressure) of the measurement mechanism MM, a process of estimating the deposition amount of the product based on the change in the measured value (pressure), and a process of outputting a predetermined signal to the valve B L2 to increase the supply flow rate of the purge gas to the injection holes 91, 92, 93 or outputting a predetermined signal to an alarm device not shown to sound an alarm when the estimated deposition amount of the product exceeds a threshold value are employed, as described in the aforementioned "configuration example 1".

Example of construction 4

Harvesting and seeding as a measuring mechanism MM adopts a flowmeter.

As described in the above-mentioned "configuration example 2", the seed control mechanism CX employs a process of constantly or periodically monitoring changes in the measured value (flow rate) of the measurement mechanism MM, a process of estimating the deposition amount of the product based on the changes in the measured value (flow rate), and a process of outputting a predetermined signal to the valve B L2 to increase the supply flow rate or supply pressure of the purge gas to the injection holes 91, 92, 93, or outputting a predetermined signal to an alarm device, not shown, to sound an alarm when the estimated deposition amount of the product exceeds a threshold value.

Additional structural example

When the clogging level of the gas supply system SS described above is high, the control means CX may perform control so as to increase the gas supply pressure of the gas supply system SS in stages (hereinafter, referred to as "stepwise gas pressure increase control"). In this case, the warning level may be set in accordance with the stage and output.

As described above, in the middle of the stepwise increase of the gas supply pressure, the clogging of the gas supply system SS is eliminated by removing the deposits which are the cause of the clogging of the gas supply system SS, that is, the products accumulated in the ejection holes 91, 92, 93 or the gas supply system SS, or the stepwise gas pressure increase control may be eliminated by sensing the return of the gas pressure of the gas supply system SS to the original pressure.

When only the stepwise gas pressure increase control is difficult to cope with, the control means CX may be configured to switch (a) to the above-described intermittent injection control, (B) to switch the kind of the removal gas injected from the injection holes 91, 92, 93 from, for example, an inert gas at normal temperature to a high-temperature gas, or (C) to switch from a high-temperature gas to a high-energy gas, and the removal effect of the deposited product is shifted to a larger one (a → B → C).

In a situation where the removal of the product accumulated in the gas injection from the injection holes 91, 92, 93 is difficult, the control means CX is configured to promote the disassembly and maintenance or replacement of the vacuum pump by outputting a predetermined signal (HE L P signal) to the external device M.

Summary of the above

As described above, in the vacuum pump P1 of the present embodiment, as a specific configuration of the removal mechanism RM for removing the product deposited on the inner wall surface of the flow path R, the removal mechanism RM has a structure in which the inner wall surface of the flow path R is provided with the ejection hole 91, 92, 93, 94, or 95 having one end open, and the removal gas is ejected into the flow path R from the ejection hole 91, 92, 93, 94, or 95. Therefore, the product deposited on the inner wall surface of the flow path R is not subjected to the conventional heating and seeding of the pump but is forcibly detached and removed by the physical force of the removal gas injected from the injection holes 91, 92, 93, 94, or 95, and therefore, there is no possibility of occurrence of defects (for example, damage due to a decrease in the material strength of the rotor RT, deformation due to creep deformation of the rotor RT, contact between the deformed rotor RT and a fixed part located on the outer periphery thereof, damage of the rotor RT and the fixed part due to the contact, and the like) caused by the conventional heating and seeding of the pump, and the product deposited on the flow path R in the vacuum pump P1 is preferably removed.

Further, according to vacuum pump P1 of the present embodiment, it is possible to use in combination with the heating of the pump, seeding and heat-insulating, and it is possible to reduce the energy necessary for the heating of the pump, seeding and heat-insulating by the combined use.

Further, the vacuum pump P1 according to the present embodiment is configured to output a maintenance request signal to the external device M, and is configured to suppress an influence of the injection of the purge gas on the processing of the external device M and to prevent an influence on the operation of the external device M only when the purge gas is injected from the injection holes 91, 92, and 93 upon receiving a command (specifically, a maintenance permission signal) from the external device M.

The present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art within the technical idea of the present invention.

For example, the present invention can be applied to a vacuum pump (so-called turbo molecular pump) of a type in which a screw-groove pump stage PS is omitted from the vacuum pump P1 shown in fig. 1, that is, a type in which gas is discharged only through a vane exhaust stage PT.

In the application example of the present invention, the screw groove pump stage PS shown in fig. 1 is omitted, and therefore the 2 nd jet hole 92 and the purge gas supply passage 11B shown in the drawing are disposed in the pump mount 1B. In the application example of the present invention described above, the final gap GE communicating with the downstream outlet of the inter-blade exhaust flow path R1 (a flow path formed by the gap set between the rotor blade 6 provided on the outer peripheral surface of the rotor R and the fixed blade 7 fixed and positioned inside the outer casing 1) is configured as a gap between the fixed blade 7E or the rotor blade 6 constituting the lowest-stage blade exhaust stage PTn and the pump mount 1B. In this case, since the product may be deposited on the inner wall surface (specifically, the surface of the pump mount 1B constituting the final gap GE) in the vicinity of the downstream outlet of the inter-vane exhaust flow path R2, a structure in which one end of the No. 2 injection hole 92 is opened in the inner wall surface in the vicinity of the downstream outlet of the inter-vane exhaust flow path R2 may be employed to remove the deposited product.

The present invention is applicable to a drag pump such as a radial flow type (sigma-delta) pump, in addition to the axial flow type vacuum pump such as the vacuum pump P1 of the present embodiment described above.

Description of the reference numerals

1 outer case

1A pump casing

1B pump base

2 air intake

3 exhaust port

4 stator pole

5 rotating shaft

6 rotating blade

7 fixed blade

8 thread groove exhaust stator

81 thread groove

91 st injection hole

92 nd injection hole 2

93 the 3 rd injection hole

94 th spray hole

95 th injection hole

11A, 11B, 11C, 11D, 11E degassing gas supply path

B L1, B L2, B L3, B L4 valves

CX control mechanism

DR driving mechanism

EN maintenance enable signal

EX exhaust port

EX1 porous tube

GE Final gap

GT gas supply source

MB1 radial magnetic bearing

MB2 axial magnetic bearing

MO driving motor

MM sensing mechanism

P1 vacuum pump

P2 auxiliary pump

Porous PP part

PS thread groove pump stage

PT wing exhaust stage

PT1 uppermost wing exhaust stage

PTn lowest stage wing exhaust stage

P L board

Flow path of R gas

R1 exhaust flow path between blades

R2 thread groove exhaust flow path

R3 Pump internal discharge Port side flow passage

RM removal mechanism

RT rotator

RQ maintenance request signal

S spacer

SP supporting mechanism

SS gas supply system

TK buffer tank

U1 shielding component

U2 is a non-blocking portion.