JP2002021775A - Turbo molecular pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent adhesion of a caking substance inside a turbo molecular pump. SOLUTION: When a rotor 6 is turned, gas is sucked from a suction port 2 and discharged from an exhaust port 3 via a gas flow passage because of action of a moving blade 5, a stationary blade 4, and a thread groove pump step 9. In the downstream of the gas flow passage, a radiating plate 20 is arranged, and to the radiating plate 20, heat from an electric heater 14 is supplied via a good heat conductor 20a. Therefore, the downstream of the gas flow passage can be heated by the radiating plate 20, and adhesion of a caking substance is prevented in this part. The radiating plate 20 is brought into contact with a spacer 19 by means of a heat conduction part 20a, so that the downstream gas flow passage is effectively heated when a stationary blade 4b in the downstream is heated. Because heat insulating spacers 18a, 18b are arranged, a casing 1 is prevented from being heated unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbocharger in which a plurality of moving blades (rotating blades) and stationary blades (fixed blades) arranged alternately in an axial direction evacuate gas sucked from an intake port to an exhaust port. It relates to a molecular pump. In particular, the present invention is devised so as to effectively prevent the solidified material from adhering in the turbo molecular pump even when a gas that solidifies when the gas partial pressure is increased is sucked.

[0002]

FIG. 3 is a longitudinal sectional view of a conventional turbo-molecular pump. As shown in FIG.
The (pump body) is provided with a gas intake port 2 and a gas exhaust port 3, between which a stationary blade (fixed blade) 4 is provided with a spacer 19.
Is fixed in position.

A rotor 6 is provided with a rotor blade (rotor blade) 5 and a thread groove pump stage 9, and is rotated by a rotary shaft 7.
The plurality of moving blades 5 and the plurality of stationary blades 4 are arranged alternately in the axial direction.

In order to rotate the rotor 6 at a high speed, an upper magnetic bearing 10, a lower magnetic bearing 11, and an axial bearing are provided between the rotating shaft 7 and a stator 8 arranged around the rotating shaft 7. , A magnetic bearing 12 and a motor 13 are provided.

A heating unit 15 located outside the casing 1
Are heated by the electric heater for heating 14, and transfer heat to the heat radiating plate 20 through the good heat conductor 17.

A heat insulating spacer 18 is interposed between the heating unit 15 and the casing 1, and the casing 1 and the stator 8
Are thermally isolated from the heating section 15, the good thermal conductor 17, and the heat sink 20. The space between the outer peripheral surface of the heat radiating plate 20 and the spacer 19 inside the casing 1 has a heat shielding plate 2.
The heat shield plate 21 shields the radiant heat from the heat radiating plate 20 from being transmitted to the spacer 19 and the casing 1 side.

A seal is provided between the heat radiating plate 20 and the casing 1 by an O-ring 23 so as to prevent gas from bypassing.

The casing 1 has a cooling passage 22 for cooling.
The casing 1 is cooled by the cooling water passing through the cooling passage 22, so that the temperature of the rotor 6 made of an aluminum alloy material is suppressed to a permissible temperature or lower.

In the turbo molecular pump described above, when the rotor 6 having the moving blade 5 and the rotating shaft 7 is rotated at a high speed by the motor 13, the gas flows from the gas inlet 2 to the moving blade 5, the stationary blade 4 and the screw groove pump stage. The gas flows through the gas flow path 9 in the direction of the exhaust port 3 and is evacuated, and the intake port 2 has a high vacuum and the exhaust port 3 has a low vacuum.

At this time, the heating unit 15 is heated by a heating means such as an electric heater 14 and the heat of the heating unit 15 is
The heat is transmitted to the radiator plate 20 through the radiator plate 7, and the radiator plate 20 is heated to increase the gas temperature of the screw groove pump stage 9, the rotating body and its peripheral portion, thereby preventing the solidified matter from adhering.

Here, "adhesion of solidified matter" will be described. This turbo molecular pump is used, for example, when evacuating a semiconductor manufacturing apparatus. In this case,
Aluminum chloride gas may be sucked. The sublimation characteristic of this aluminum chloride is as shown in FIG. 4, and the sublimation temperature increases as the gas pressure increases, and the range below the graph line becomes solid. In the turbo-molecular pump, since the intake port 2 side has a high vacuum (low partial pressure) and the exhaust port 3 side has a low vacuum (high partial pressure), the partial pressure is high on the screw groove pump stage 9 side of the exhaust port 3 side. And solidification easily occurs. Therefore, heating is performed on the side of the exhaust port 3 having a high partial pressure,
This prevents the solid matter from adhering.

[0012]

In a conventional turbo-molecular pump, when the gas is exhausted, the rotating body becomes hot due to heat generated inside the pump, so that the aluminum alloy material used for the rotating body material is creeped or creeped. As a countermeasure against this, the casing (pump body) 1 is cooled by cooling means such as cooling water.

However, when the casing 1 is cooled, the temperature in the casing 1 becomes lower than the sublimation temperature of the gas to be exhausted, solidified matter adheres to the inside of the gas flow path, and the performance of the pump deteriorates and failure due to contact may occur. In order to cause this, the heat sink 20 was provided in the gas flow path around the screw groove pump stage 9 to the gas outlet and heated by a heating means such as an electric heater to heat the gas temperature to the solidification temperature or higher. In the vicinity of the stationary blade 4 on the downstream side close to the exhaust port 3 in a portion that does not reach the exhaust port, a phenomenon that solidified matter adheres has occurred.

For this reason, there is a problem that maintenance work for periodically removing the solidified material is required, and the operation of the turbo molecular pump is reduced.

When the casing 1 is cooled, the temperature in the casing 1 becomes lower than the sublimation temperature of the exhaust gas,
The solidified substance adheres to the inside of the gas flow path, causing a decrease in pump performance or a failure due to contact.
In order to provide a heat radiating plate 20 in a gas flow path around a gas outlet and heat it by a heating means such as an external electric heater to heat the gas temperature to a solidification temperature or higher, it is necessary to increase the capacity of the electric heater. there were.

The present invention proposes to solve the above-mentioned problems of the prior art. By contacting a heat sink with a stationary vane or a spacer on the downstream side, the gas temperature is heated to a temperature higher than the sublimation temperature and solidified. It is an object of the present invention to provide a turbo-molecular pump capable of preventing the attachment of an object and eliminating maintenance work such as cleaning of the inside of a casing.

Another object of the present invention is to solve the above-mentioned problem of the prior art. A good heat conductor having a coil embedded therein is mounted on a heat sink, and a high-frequency current flows through the coil. It is another object of the present invention to provide a turbo molecular pump capable of directly heating a heat sink by heat generated by a good heat conductor and loss of the heat sink itself, and heating the heat sink to a temperature equal to or higher than a sublimation temperature of gas with a small amount of electric power.

[0018]

In order to solve the above-mentioned problems, a construction of the present invention comprises a plurality of moving blades and a plurality of stationary blades arranged alternately in an axial direction in a casing, and the plurality of stationary blades mutually. A spacer arranged in the axial direction to fix the position while being spaced apart in the axial direction, and heat supplied from the outside to the gas flow path located downstream of the moving blade and the stationary blade in the gas flow path. In the turbo-molecular pump provided with a heat radiating plate for heating at a temperature, a heat conducting portion that conducts heat from the heat radiating plate to at least the most downstream stationary blade of the stator blades, and a heat conducting portion disposed downstream of the heat conducting portion. And a heat insulating spacer on the downstream side for preventing heat from being transmitted to the casing, and an upstream heat insulating spacer interposed in the spacer while being located on the upstream side of the heat conducting portion. It is characterized by.

Further, the structure of the present invention is characterized in that the position of the heat insulating spacer on the upstream side is determined by the gas pressure in the casing, the gas solidification temperature, and the moving blade temperature.

[0020] Further, according to the structure of the present invention, a plurality of moving blades and a plurality of stationary blades alternately arranged in the axial direction in a casing;
A spacer arranged in the axial direction to fix the positions of the plurality of stationary blades while being spaced apart from each other in the axial direction; and a gas flow path located downstream of the moving blade and the stationary blade in the gas flow path. And a radiator plate for heating the radiator plate with heat supplied from the outside, wherein a heating means for directly heating the radiator plate is provided in the casing.

Further, the configuration of the present invention is characterized in that a coil is used as the heating means. Further, the coil is sealed. Further, a high-frequency current is passed through the coil.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings. The same parts as in the prior art will be described with the same reference numerals.

<First Embodiment> FIG. 1 is a longitudinal sectional view of a turbo-molecular pump according to a first embodiment of the present invention. As shown in the figure, a casing 1 (pump main body) is provided with a gas inlet port 2 and a gas outlet port 3, between which a stationary blade (fixed blade) 4 is fixed in position by a spacer 19 and attached. Have been.

A rotor 6 (rotating blade) 5 and a thread groove pump stage 9 are attached to the rotor 6, and are rotated by a rotating shaft 7.
The plurality of moving blades 5 and the plurality of stationary blades 4 are arranged alternately in the axial direction. As a result, in the gas flow path from the intake port 2 to the exhaust port 3, a plurality of alternately arranged moving blades 5 and a plurality of stationary blades 4, and a thread groove pump stage 9 are sequentially installed along the gas flow direction. ing.

In order to rotate the rotor 6 at a high speed, an upper magnetic bearing 10, a lower magnetic bearing 11, and an axial bearing are provided between the rotating shaft 7 and a stator 8 disposed around the rotating shaft 7. , A magnetic bearing 12 and a motor 13 are provided.

The heating unit 15 located outside the casing 1
Are heated by the electric heater for heating 14, and transfer heat to the heat radiating plate 20 through the good heat conductor 17. The heat radiating plate 20 heats the gas flow path where the screw groove pump stage 9 is located, that is, heats the gas flow path located downstream of the moving blade 5 and the stationary blade 4 in the gas flow path.

A heat insulating spacer 18 is interposed between the heating section 15 and the casing 1, and the casing 1 and the stator 8
Are thermally isolated from the heating section 15, the good thermal conductor 17, and the heat sink 20. The space between the outer peripheral surface of the heat radiating plate 20 and the spacer 19 inside the casing 1 has a heat shielding plate 2.
The heat shield plate 21 shields the radiant heat from the heat radiating plate 20 from being transmitted to the spacer 19 and the casing 1 side.

An O-ring 23 is provided between the heat radiating plate 20 and the casing 1 to prevent gas from bypassing.

The casing 1 has a cooling passage 22 for cooling.
The casing 1 is cooled by the cooling water passing through the cooling passage 22, so that the temperature of the rotor 6 made of an aluminum alloy material is suppressed to a permissible temperature or lower.

The configuration up to this point is the same as that of the prior art, but the present embodiment further employs the following new configuration.

That is, the plurality of spacers 19 are arranged side by side in the axial direction to fix the positions of the plurality of stationary blades 4 while being spaced apart in the axial direction. The radiator plate 20 is provided with the screw groove pump stage 9.
In the gas flow path between the gas flow path and the spacer 19, that is, in the gas flow path that is located downstream of the moving blades 5 and the stationary blades 4 in the gas flow path, In order to transfer heat to the blades 4b, the plurality of spacers 19 are in surface contact with the spacers 19 located below the downstream stationary blades 4b via the heat conducting portions 20a. The heat sink 20 may be configured to be in contact with the downstream stationary blade 4b.

Further, a heat insulating spacer 18a is provided between the downstream stationary blade 4b near the exhaust port 3 and the upstream stationary blade 4a near the intake port 2, and the heat radiating plate 2a is connected via the heat conducting portion 20a.
A heat insulating spacer 18b is also provided between the spacer 19 contacting with the casing 0 and the casing 1 immediately below the heat conducting portion 20a to isolate the heat.

The position of the heat insulating spacer 18a is determined in consideration of the gas pressure in the casing 1, the gas solidification temperature, and the temperature of the moving blade 5. Specifically, (1) the position of the heat insulating spacer 18a can be set further upstream when the gas pressure is high, and (2) the position of the heat insulating spacer 18a when the gas solidification temperature is high. (3) When the moving blade temperature is high, the position of the heat insulating spacer 18a can be set further downstream.

In the above turbo molecular pump, when the rotor 6 having the moving blades 5 and the rotating shaft 7 is rotated at a high speed by the motor 13, the gas flows from the gas inlet port 2 to the moving blades 5, the stationary blades 4 and the screw groove pump stage. The gas flows through the gas flow path 9 in the direction of the exhaust port 3 and is evacuated, and the intake port 2 has a high vacuum and the exhaust port 3 has a low vacuum.

At this time, the heating unit 15 is heated by a heating means such as an electric heater 14 and the heat of the heating unit 15 is
The heat is transmitted to the radiator plate 20 through the radiator plate 7, and the radiator plate 20 is heated to increase the gas temperature of the screw groove pump stage 9, the rotating body and its peripheral portion, thereby preventing the solidified matter from adhering.

At this time, the radiating temperature from the radiating plate 20 is
The electric heater 14 for heating the heating unit 15 is controlled such that the temperature is higher than the sublimation temperature of the gas within a range that does not affect the strength of the rotating body or the like made of an aluminum alloy material.

On the other hand, the heat generated by the rotor 6 is
A path which is transmitted from the upstream stationary blade 4a → the spacer 19 → the casing 1 and cooled by convection of the casing 1 and the rotor 6
The path from the stator 8 to the casing 1 and cooled by the cooling water in the cooling passage 22 keeps the temperature rise of the rotating body below the allowable temperature.

In the turbo molecular pump described above, the gas pressure from the intake port 2 is controlled by the moving blade 5, the stationary blade 4, and the screw groove pump stage 9.
, The pressure gradually increases, and the air is exhausted from the exhaust port 3. In response to this change in gas pressure, the heat radiating plate 20 is arranged at a position where the gas pressure increases and the sublimation temperature increases, and the heat radiation temperature is set so as to be higher than the gas sublimation temperature.

Further, since the heat radiating plate 20 is in contact with the downstream stationary blade 4b or the downstream spacer 19, the heat radiating plate 20 is in the gas passage of the screw groove pump stage 9 and the gas passage of the downstream stationary blade 4b. By heating the temperature to a temperature equal to or higher than the sublimation temperature, adhesion of solidified matter can be prevented. For this reason, maintenance work such as cleaning of the inside of the casing 1 can be omitted, and continuous operation can be performed.

Further, the downstream stationary blade 4b to be heated and the upstream stationary blade 4 serving as a heat transfer path for cooling the rotor temperature.
Since the heat insulating spacers 18a are inserted between the gas flow paths a, it is possible to raise only the temperature of the downstream gas flow path having a high sublimation temperature without increasing the overall temperature of the rotor. As a result, it is possible to prevent the process gas from solidifying and adhering without reducing the creep or strength of the rotating body.

As described above, in the first embodiment, the temperature of the gas flow path is raised by the heat radiating plate 20 so that the temperature is not affected by the strength of the rotating body or the like made of an aluminum alloy material and the gas is sublimated. Since the temperature is higher than the temperature, there is an effect that the solidified material is prevented from adhering to the gas flow path. In the first embodiment, a turbo molecular pump having a thread groove pump stage has been described, but the present invention can be applied to a turbo molecular pump having no thread groove pump stage.

<Second Embodiment> FIG. 2 is a longitudinal sectional view of a turbo-molecular pump according to a second embodiment of the present invention. As shown in the figure, a casing 1 (pump main body) is provided with a gas inlet port 2 and a gas outlet port 3, between which a stationary blade (fixed blade) 4 is fixed in position by a spacer 19 and attached. Have been.

A rotor (rotating blade) 5 and a thread groove pump stage 9 are mounted on the rotor 6 and are rotated by a rotating shaft 7.
The plurality of moving blades 5 and the plurality of stationary blades 4 are arranged alternately in the axial direction. As a result, in the gas flow path from the intake port 2 to the exhaust port 3, a plurality of alternately arranged moving blades 5 and a plurality of stationary blades 4, and a thread groove pump stage 9 are sequentially installed along the gas flow direction. ing.

In order to rotate the rotor 6 at a high speed, an upper magnetic bearing 10, a lower magnetic bearing 11, and an axial bearing are provided between the rotating shaft 7 and a stator 8 arranged around the rotating shaft 7. , A magnetic bearing 12 and a motor 13 are provided.

The heating unit 15 located outside the casing 1
Are heated by the electric heater for heating 14, and transfer heat to the heat radiating plate 20 through the good heat conductor 17. The heat radiating plate 20 heats the gas flow path where the screw groove pump stage 9 is located, that is, heats the gas flow path located downstream of the moving blade 5 and the stationary blade 4 in the gas flow path.

A heat insulating spacer 18 is interposed between the heating unit 15 and the casing 1, and the casing 1 and the stator 8
Are thermally isolated from the heating section 15, the good thermal conductor 17, and the heat sink 20. The space between the outer peripheral surface of the heat radiating plate 20 and the spacer 19 inside the casing 1 has a heat shielding plate 2.
The heat shield plate 21 shields the radiant heat from the heat radiating plate 20 from being transmitted to the spacer 19 and the casing 1 side.

Further, a seal is provided between the heat radiating plate 20 and the casing 1 side by an O-ring 23 so that gas does not bypass.

The casing 1 has a cooling passage 22 for cooling.
The casing 1 is cooled by the cooling water passing through the cooling passage 22, so that the temperature of the rotor 6 made of an aluminum alloy material is suppressed to a permissible temperature or lower.

Although the configuration up to this point is the same as that of the conventional technology, the present embodiment further employs the following new configuration.

That is, a good heat conductor 24 is attached to the lower end surface of the heat sink 20. A donut-shaped groove for embedding the coil 25 is formed on an end surface (upper end surface) of the good heat conductor 24, and the coil 25 is embedded in the groove. The groove is molded and sealed with an epoxy resin or the like, which is a material excellent in corrosion resistance, insulation, and airtightness, in order to prevent intrusion of corrosive gas with the coil embedded.

The connector 26 is for supplying a high-frequency current to the coil 25 from the outside, and has good airtightness so as to maintain a vacuum inside the pump. A lead wire connected to the coil 25 is connected to the pins of the connector 26, and a high frequency power supply 27 such as an inverter arranged outside is connected to the pins. For this reason, the high-frequency current output from the high-frequency power supply 27 is supplied to the coil 25 via the connector 26.

In the above turbo molecular pump, when the rotor 6 having the moving blades 5 and the rotating shaft 7 is rotated at a high speed by the motor 13, the gas flows from the gas inlet 2 to the moving blades 5, the stationary blades 4 and the screw groove pump stage. The gas flows through the gas flow path 9 in the direction of the exhaust port 3 and is evacuated, and the intake port 2 has a high vacuum and the exhaust port 3 has a low vacuum.

At this time, a high-frequency current is applied to the coil 25 embedded in the good heat conductor 24 attached to the heat radiating plate 20 provided inside the pump by a high-frequency power supply 27 such as an inverter, so that the coil 25 is generated. Copper loss, and
The good heat conductor 24 is heated by the iron loss generated in the good heat conduction band 24, and transmits heat to the radiator plate 20 directly connected to the good heat conductor 24, thereby heating the radiator plate 20. Since the radiator plate 20 thus heated heats the gas flow path, the solidified material is prevented from adhering to the screw groove pump stage 9, the downstream stationary blades 4b, the rotating body, and the periphery thereof. The “copper loss” mentioned above is
The "iron loss" is proportional to the number of turns of the coil 25, the high-frequency current value, and the frequency of the high-frequency current, and the above-mentioned "iron loss" is proportional to the number of turns of the coil 25, the high-frequency current value, and approximately the square of the frequency of the high-frequency current.

The high-frequency current value or frequency is controlled so that the heat radiation temperature from the heat radiation plate 20 is higher than the sublimation temperature of the gas within a range that does not affect the strength of the rotating body or the like made of an aluminum alloy material. . The high-frequency power supply 27 supplies a high-frequency current having a current value of 2 to 3 A and a frequency of 2000 to 3000 Hz to the coil 25.

Further, in order to prevent solidified substances from adhering to the exhaust port 3, a heating unit 1 provided outside the pump of the exhaust port 3 is provided.
5 is heated by the electric heater 14, and the heat of the heating unit 15 is transmitted to the good heat conductor 24 via the good heat conductor 17 inside the pump,
A structure for heating the radiator plate 20 can be used together. FIG. 2 shows an example in which this mechanism is used in combination.

Also in this case, the electric heater 14 for heating the heating unit 15 is controlled so that the temperature is higher than the sublimation temperature of the gas within a range that does not affect the strength of the rotating body made of an aluminum alloy material. .

In the turbo molecular pump described above, the gas pressure from the intake port 2 is controlled by the moving blade 5, the stationary blade 4, and the screw groove pump stage 9.
, The pressure gradually increases, and the air is exhausted from the exhaust port 3. In response to this change in gas pressure, the heat radiating plate 20 is arranged at a position where the gas pressure increases and the sublimation temperature increases, and the heat radiation temperature is set so as to be higher than the gas sublimation temperature.

Moreover, since the high-frequency current is applied to the coil 25 to directly heat the heat sink 20, the heat transfer loss due to the conventional casing 1 can be eliminated, and the temperature can be raised to the target temperature with low power. became. That is, the casing 1
Since the radiator plate 20 is directly heated by the eddy current without heating the entire body, effective heating can be performed by aiming only at the portion of the gas flow path where solidification is likely to occur. Further, if the frequency of the high-frequency current supplied to the coil 25 is increased, the size can be further reduced.

Further, since the temperature of the heat radiating plate 20 is directly increased in the inside, the heating mechanism can be simplified and the power consumption can be reduced, which contributes to the downsizing of the heating section.

As described above, in the second embodiment, the temperature of the gas flow path is raised by the heat radiating plate 20 so that the temperature is not affected by the strength of the rotating body made of an aluminum alloy material and the power consumption is low. The compact and simple mechanism has the effect of preventing solidified matter from adhering to the gas flow path. In the second embodiment, a turbo molecular pump having a thread groove pump stage has been described. However, the present invention can be applied to a turbo molecular pump having no thread groove pump stage.

[0061]

According to the present invention, a plurality of moving blades and a plurality of stationary blades arranged alternately in the axial direction in the casing, and a plurality of the stationary blades A spacer arranged in the axial direction to fix the position while being spaced apart in the axial direction, and a gas flow path located downstream of the moving blade and the stationary blade in the gas flow path was supplied from the outside. In a turbo-molecular pump including a radiator plate that heats with heat, a heat conduction unit that conducts heat from the radiator plate to at least the most downstream stationary blade of the stator blades, and a downstream side of the heat conduction unit. A heat insulating spacer on the downstream side for preventing heat from being transmitted to the casing, and an upstream heat insulating spacer interposed in the spacer while being located upstream of the heat conducting portion. The configuration was adopted. In the present invention, the position of the heat insulating spacer on the upstream side is determined by the gas pressure in the casing, the gas solidification temperature, and the moving blade temperature.

With this configuration, the radiator plate heats the gas temperature in the gas flow path of the screw groove pump stage and the downstream stationary vane to a sublimation temperature or higher to prevent solidified substances from adhering and to clean the inside of the casing and the like. Since maintenance work can be eliminated and continuous operation can be performed, the operation of the turbo-molecular pump can be further enhanced, which is extremely useful in industry. Furthermore, since a heat insulating spacer is inserted between the downstream stationary blades to be heated and the upstream stationary blades serving as a heat transfer path for cooling the rotor temperature, the downstream side where the sublimation temperature is high without increasing the overall temperature of the rotor. Only the gas flow path can be heated. As a result, it is possible to prevent the process gas from solidifying and adhering without reducing the creep or strength of the rotating body.

Further, in the present invention, a plurality of moving blades and a plurality of stationary blades alternately arranged in the axial direction in the casing, and an axial direction for fixing the positions of the plurality of stationary blades while being spaced apart from each other in the axial direction. Turbo-molecular pump comprising: a spacer arranged side by side; and a radiator plate that heats a gas flow path located downstream of the moving blade and the stationary blade in the gas flow path with heat supplied from the outside. Wherein the heating means for directly heating the radiator plate is provided in the casing. In the present invention, a coil is used as the heating means, the coil is sealed, or a high-frequency current is supplied to the coil.

With such a structure, the heat sink heats the gas temperature of the gas flow path of the screw groove pump stage and the downstream stationary blade to a sublimation temperature or higher to prevent solidified substances from adhering and to clean the inside of the casing. Since maintenance work can be eliminated and continuous operation can be performed, the operation of the turbo-molecular pump can be further enhanced, which is extremely useful in industry. Furthermore, the structure in which the temperature of the heat radiating plate is directly increased in the inside can simplify the heating mechanism, and it is possible to contribute to downsizing of the heating section by reducing power consumption.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a turbo-molecular pump according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a turbo-molecular pump according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a conventional turbo-molecular pump.

FIG. 4 is a graph showing the relationship between the partial pressure of aluminum chloride (AlCl ₃ ) and the sublimation temperature.

[Explanation of symbols]

 Reference Signs List 1 casing 2 intake port 3 exhaust port 4 stationary blade 5 rotor blade 6 rotor 7 rotating shaft 8 stator 9 screw groove pump stage 10, 11, 12 magnetic bearing 13 motor 14 electric heater for heating 15 heating unit 17 good conductor 18, 18a, 18b Heat insulating spacer 19 Spacer 20 Heat sink 21 Heat shield plate 22 Cooling passage 23 O-ring 24 Good heat conductor 25 Coil 26 Connector 27 High frequency power supply

Claims (6)

[Claims] 1. A plurality of moving blades and a plurality of stationary blades alternately arranged in an axial direction in a casing, and are arranged side by side in the axial direction to fix the positions of the plurality of stationary blades while being spaced apart from each other in the axial direction. In the turbo molecular pump, comprising: a disposed spacer; and a radiator plate that heats a gas flow path located downstream of the moving blade and the stationary blade in the gas flow path with heat supplied from the outside. A heat conducting portion that conducts heat from the heat sink to at least the most downstream stationary blade of the stator blades; and a downstream portion that is disposed downstream of the heat conducting portion and that prevents heat from being transmitted to the casing. A turbo-molecular pump, comprising: a heat-insulating spacer on the side; and an upstream heat-insulating spacer positioned on the upstream side of the heat conducting portion and interposed in the spacer. 2. The turbo molecular pump according to claim 1, wherein the position of the heat insulating spacer on the upstream side is determined by a gas pressure, a gas solidification temperature, and a moving blade temperature in the casing. 3. A plurality of moving blades and a plurality of stationary blades which are alternately arranged in an axial direction in a casing, and are arranged in an axial direction so as to fix the positions of the plurality of stationary blades while being spaced apart from each other in the axial direction. In the turbo molecular pump, comprising: a disposed spacer; and a radiator plate that heats a gas flow path located downstream of the moving blade and the stationary blade in the gas flow path with heat supplied from the outside. A turbo molecular pump, wherein a heating means for directly heating a radiator plate is provided in the casing. 4. The turbo molecular pump according to claim 3, wherein a coil is used as said heating means. 5. The turbo-molecular pump according to claim 4, wherein said coil is sealed. 6. The turbo-molecular pump according to claim 4, wherein a high-frequency current flows through the coil.