JP2004308642A - Cold trap and evacuation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cold trap capable of shortening time required for regeneration and reducing running costs, and to provide an evacuation device using the cold trap together with a turbo molecular pump. <P>SOLUTION: In the cold trap 10, a heater 13 heating a cold panel 12 placed in a casing 11, a pulse tube refrigerator 14 thermally connected to the cold panel 12, and a temperature sensor 15 measuring the temperature of the cold panel 12 are connected to a controller 17 to control the temperature of the cold panel 12. The turbo molecular pump 20 is arranged downstream of the cold trap 10 in the evacuation device 100. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cold trap and an evacuation apparatus using the cold trap and a turbo molecular pump in combination.

As an example of a vacuum exhaust device that exhausts the inside of the vacuum chamber, there is a turbo molecular pump. The exhaust performance of this turbo-molecular pump differs depending on the molecular weight (molecular size) of gas molecules to be discharged. In particular, it is difficult to evacuate water vapor having a small molecular weight. For example, when the gas in the vacuum chamber is evacuated by a turbo molecular pump and evacuated to about 10 ⁻⁶ Pa to 10 ⁻¹² Pa, the residual gas in the vacuum chamber becomes: Most of it is water vapor. If such water vapor remains in the vacuum chamber, it adversely affects the degree of vacuum and the vacuum environment.

Therefore, a cold trap is provided upstream of the turbo molecular pump (generally between the vacuum chamber and the turbo molecular pump).
This cold trap allows a gas to pass through so as to come into contact with a surface cooled to a very low temperature (hereinafter referred to as a cold panel), cools water vapor contained in such a passing gas, freezes it on ice, and collects it. The apparatus is capable of obtaining a vacuum environment with less water vapor in a vacuum chamber.
By removing the water vapor from the cold trap, a gas from which water vapor has been removed in advance can flow into the turbo molecular pump, and the evacuation speed of the vacuum chamber can be improved. The cold trap can also freeze and collect other gases (eg, Br ₂ , NH ₃ , Cl ₂ , CO _2, etc.) by appropriately setting the cooling temperature.

  It should be noted that the change from solid (ice) to gas (water vapor) and the change from gas (water vapor) to solid (ice) are both called sublimation, but in the present specification, In particular, the change from gas (water vapor) to solid (ice) is called freezing, and the change from solid (ice) to gas (water vapor) is called sublimation and distinguished.

Now, there are various conventional techniques for such a cold trap. As other conventional techniques, for example, the invention described in Patent Literature 1 (turbo molecular pump) or Patent Literature 2 (cold trap and vacuum exhaust device) is known.
Patent Document 1 describes a cold trap cooled by liquid nitrogen, and Patent Document 2 describes a cold trap using a GM (Gifford McMahon) helium refrigerator.

JP-A-9-317688 (paragraphs 0022 to 0036, FIGS. 1 to 4) JP-A-11-294330 (paragraph numbers 0032 to 0049, FIGS. 1 to 3)

The cold trap is a storage system in which gas molecules are frozen and adsorbed on a cooled cold panel and stored until the entire surface of the cold panel is covered with ice.Therefore, regeneration that removes ice from the cold panel at regular intervals of operation is performed. There is a need to do.
To regenerate the cold panel, a heating method using an external heater or a method in which a pipe is arranged near the cold panel and a coolant such as a gas is heated and allowed to flow to raise the temperature of the cold panel. Has been done. However, the cold trap according to the related art has the following problems regarding the regeneration of the cold panel.

<Cold trap cooled by liquid nitrogen described in Patent Document 1>
(1) Replenishment and storage facilities for liquid nitrogen used as a refrigerant are required, and running costs are high.
(2) As shown in FIG. 1 of Patent Document 1, a cold panel (cold trap 50) is regenerated using nitrogen gas obtained by heating liquid nitrogen, but the cold panel (cold trap 50) is used for indirect heating. It takes time for the temperature to rise, and the generation rises slowly.

<Cold trap using GM helium refrigerator described in Patent Document 2>
(1) The GM type helium refrigerator 3 (see FIGS. 1 and 2 of Patent Document 2) has a long fall time until the temperature of the pipe 8 (low temperature end) becomes low. It is necessary to operate continuously with the rating. In addition, power consumption is large because the efficiency of the refrigerator is low in principle.
(2) As shown in FIG. 1 and FIG. 2 of Patent Document 2, the regeneration of the cold panel (panel 6) is performed while the GM type helium refrigerator is operating, so the piping 8 (cooling end portion) of the refrigerator 3 is used. The heating means for increasing the temperature in the step (1) requires a large capacity.
(3) Since the refrigerator 3 has a mechanical expansion piston, a gas seal for sealing the inside of the cylinder is used. The regeneration temperature is limited to about 100 ° C. or less due to various conditions such as the heat-resistant temperature of the resin portion used for the gas seal and gas release, and the regeneration efficiency is deteriorated and the regeneration time is increased.

  An object of the present invention, which has been made in view of the above problems, is to provide a cold trap that requires a short time for regeneration (hereinafter, referred to as a regeneration time) and reduces running costs, and a cold trap having such advantages. An object of the present invention is to provide a vacuum exhaust device using a turbo molecular pump in combination with a trap.

In order to solve the above-mentioned problem, a cold trap according to the first aspect of the present invention includes:
A casing,
A cold panel installed in the casing,
Heating means for heating the cold panel;
A refrigerator having a compressor, an expander, and a cooling end, wherein the cooling end is disposed at least inside the casing while being thermally connected to the cold panel;
Temperature measurement means for measuring the temperature of the cold panel;
Heating means, a temperature control means to which the refrigerator and the temperature measurement means are connected,
A cold trap with
The temperature control means controls the refrigerator or the heating means based on the temperature of the cold panel measured by the temperature measurement means so that the temperature of the cold panel becomes a predetermined temperature.

  According to this configuration, by controlling the temperature of the refrigerator or the heating means, the surface temperature (trap surface) of the cold panel can be set to an arbitrary temperature that is optimal for adsorption and regeneration.

Further, the cold trap according to the second aspect of the present invention includes:
The cold trap according to claim 1,
The temperature control range of the cold panel ranges from a minimum of 60K (−213 ° C.) to a maximum of 573K (+ 300 ° C.).

  According to this configuration, with regard to the temperature of the cold panel, at the time of adsorption, an effective temperature according to the gas adsorption characteristics is selected to enable optimal selective adsorption, and at the time of regeneration processing, effective at releasing moisture. The temperature can be selected and controlled so that the temperature of the trap surface of the cold panel becomes optimal.

Further, the cold trap according to the third aspect of the present invention includes:
In the cold trap according to claim 1 or 2,
The heating means is built in a cold panel.

  According to this configuration, the cold panel can be heated uniformly and quickly, and outgas from components such as a heater is not released into the vacuum chamber.

Further, the cold trap of the invention according to claim 4 of the present invention is:
In the cold trap according to any one of claims 1 to 3,
The expander is a pulse tube expander.

  According to this configuration, the expander of the pulse tube refrigerator (hereinafter simply referred to as a pulse tube expander) does not have a movable part such as a nonmetallic sliding member unlike a GM type refrigerator, and is entirely made of metal. Therefore, the heating temperature at the time of the regeneration process can be set to be much higher than that of the GM refrigerator having the movable portion, and the reliability against the heat shock can be improved.

Further, the cold trap of the invention according to claim 5 of the present invention is:
In the cold trap according to any one of claims 1 to 4,
The cold panel is made of pure titanium having a higher thermal conductivity than stainless steel in a low temperature range.

  According to this configuration, the surface temperature distribution of the cold panel can be made more uniform than that of a commonly used stainless steel material, so that the effective surface area of the cold panel can be increased.

The cold trap according to claim 6 of the present invention is:
In the cold trap according to any one of claims 1 to 4,
The cold panel is characterized by using copper or a copper alloy having a high thermal conductivity in a low temperature range as a material.

  According to this configuration, similarly to pure titanium, the surface temperature distribution of the entire cold panel can be made uniform as compared with a commonly used stainless steel material, so that the effective surface area of the cold panel can be increased.

The cold trap according to claim 7 of the present invention is:
The cold trap according to claim 6,
The cold panel is characterized in that a protective layer for improving corrosion resistance is formed on the surface thereof.

  By forming a protective layer such that gas does not come into contact with copper or copper alloy, corrosion of the surface of copper or copper alloy can be prevented.

Further, the cold trap of the invention according to claim 8 of the present invention is:
In the cold trap according to any one of claims 1 to 7,
The cold panel is characterized in that the surface area of a trap surface for freezing and trapping water molecules is increased, and the outer surface other than the trap surface is made glossy.

  According to this configuration, by adopting, for example, a plain surface or an uneven surface formed by protrusions as the trap surface on the low temperature side, it is possible to increase the surface area capable of adsorbing gas. In addition, the outer surface other than the trapping surface can be conversely made a glossy surface having a low emissivity to reduce the amount of heat entering from the room temperature side.

Further, the vacuum evacuation apparatus according to the ninth aspect of the present invention includes:
The cold trap according to any one of claims 1 to 8, which causes the remaining gas obtained by freeze-trapping water molecules to flow out,
A turbo molecular pump for exhausting gas flowing out of the cold trap,
It is characterized by having.

  According to this configuration, the input and output of the refrigerator can be changed according to the load on the cold panel during gas adsorption, and during regeneration, the refrigerator can be stopped and the heating means can be uniformly heated to a high temperature. Therefore, it is possible to provide a vacuum evacuation apparatus having a high operation rate and a low running cost when used in combination with a turbo molecular pump.

  According to the present invention as described above, it is possible to provide a cold trap that has a short regeneration time and reduces running costs, and a vacuum exhaust device that uses a cold trap having such advantages and a turbo molecular pump in combination. it can.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a side cross-sectional view of a cold trap of the present embodiment, and a vacuum exhaust device including a cold trap and a turbo molecular pump. FIG. 2 is a block diagram of the vacuum exhaust device of the present embodiment. FIG. 3 is a block diagram of a temperature control system. FIG. 4 is a block diagram of the vacuum exhaust device of the present embodiment.

As shown in FIGS. 1 and 2, the evacuation apparatus 100 of this embodiment includes a cold trap 10 and a turbo molecular pump 20. FIG. 1 shows a specific configuration, and FIG. 2 shows a simplified block diagram.
The cold trap 10 includes a casing 11, a cold panel 12, a heater 13, a pulse tube refrigerator 14, a temperature sensor 15, a terminal unit 16, a controller 17, and a power supply 18.

  The casing 11 includes a body 11a and a flange 11b. The body 11a has a cylindrical shape, and the flange 11b is formed so as to be connected to the periphery of the upper and lower openings of the body 11a.

The cold panel 12 includes an outer peripheral panel 12a, an inner peripheral panel 12b, and a support portion 12c.
The outer peripheral panel 12a is a substantially cylindrical body, and a support portion 12c such as a rod or a pipe is attached to the inside thereof. The inner peripheral panel 12b is a substantially cylindrical body large enough to be housed inside the outer peripheral panel 12a, and is supported and fixed to the support portion 12c. The outer peripheral panel 12a, the inner peripheral panel 12b, and the support portion 12c are thermally connected. The cold panel 12 is installed at substantially the center in the casing 11.

Such a cold panel 12 is manufactured using pure titanium having a higher thermal conductivity than stainless steel at a cryogenic temperature of about 70 K (−203 ° C.). By using the cold panel 12 made of pure titanium as a material, the surface temperature distribution can be made uniform as compared with a commonly used stainless steel material, and the effective surface area of the cold panel 12 can be increased.
Pure titanium also has the advantage of high corrosion resistance because it does not rust against water vapor or gas.

  The cold panel 12 may be made of copper or a copper alloy having a higher thermal conductivity than stainless steel in a very low temperature range of about 70 K (−203 ° C.). Since the thermal conductivity is high as described above, the heat of the cooling end 14a is immediately conducted to the entire cold panel 12, and the entire cold panel 12 becomes the same temperature as the cooling end 14a in a short time. In this case, the surface temperature distribution of the entire cold panel 12 is uniform and does not have a non-uniform temperature distribution unlike a stainless steel material having a small thermal conductivity that is generally used, so that the effective surface area of the cold panel 12 can be increased. Thus, water molecules can be collected on the entire surface of the cold panel 12.

  Further, the cold panel 12 made of copper or a copper alloy is provided with a protective layer (specifically, a nickel plating layer) for improving corrosion resistance on the surface thereof so that the gas does not come into contact with the copper / copper alloy. Thereby, corrosion resistance is improved for copper or copper alloy which is easily corroded (that is, oxidized) so that gas (particularly water vapor) does not cause patina or the like. The thermal conductivity of copper or a copper alloy and the corrosion resistance of nickel make it suitable for use unique to the cold trap 10 (freeze collection of water molecules).

Further, the inner side surfaces (trap surfaces) of the outer peripheral panel 12a and the inner peripheral panel 12b are formed in a plain shape by, for example, blasting or peening to increase the surface area. It is sufficient that the surface area can be increased, and an uneven surface formed with a large number of protrusions may be used.
Further, the outer surfaces of the outer peripheral panel 12a and the inner peripheral panel 12b (surfaces facing the body 11a of the casing 11) are mirror-finished (glossy surfaces) with as low an emissivity as possible to reduce the emissivity. Thus, the amount of heat entering from the room temperature side can be reduced.

The heater 13 is a specific example of the heating means of the present invention. For example, the heater 13 is a cylindrical planar heater that is hermetically sealed in a sandwich inside the outer peripheral panel 12a and the inner peripheral panel 12b of the cold panel 12. In addition, the configuration is such that current lines and insulating portions are not exposed from the trap surfaces of the outer peripheral panel 12a and the inner peripheral panel 12b of the cold panel 12.
The heater 13 may be a linear heater such as a sheathed heater as long as it can be installed substantially uniformly on the outer peripheral panel 12a and the inner peripheral panel 12b of the cold panel 12. When the outer peripheral panel 12a and the inner peripheral panel 12b of the cold panel 12 are manufactured as a casting, a cast heater may be used, and various heaters can be used.

  The pulse tube refrigerator 14 is a specific example of the refrigerator of the present invention, and includes a cooling end 14a, an expander 14b, and a compressor 14c. The pulse tube refrigerator 14 is a closed type refrigerator using helium gas as a refrigerant, and is configured such that the cooling end 14a is cooled by a Stirling cycle of the expander 14b and the compressor 14c. In a normal Stirling type refrigerator, an expander is mechanically constituted by a piston and a cylinder. However, the pulse tube refrigerator 14 has no moving parts, and gas (gas piston) in a pulse tube (not shown) is supplied to the expander. Has a role.

The pulse tube refrigerator 14 is mounted such that the compressor 14c and the expander 14b are mounted on the outer surface of the body 11a of the casing 11, and at least the cooling end 14a is disposed inside the body 11a of the casing 11. Can be
The outer panel 12a is thermally connected to the cooling end 14a of the pulse tube refrigerator 14, and the entire cold panel 12 passes through the outer panel 12a, the support portion 12c, and the inner panel 12b. It is cooled by 14.

The temperature sensor 15 is a specific example of the temperature measuring means of the present invention, and although not shown in detail in FIG. 1, a sheath type sensor is attached to the outer peripheral panel 12a or the inner peripheral panel 12b of the cold panel 12, and the cold panel Twelve main parts can be measured.
The terminal 16 is provided for drawing out a current line connected to the heater 13 and a signal line connected to the temperature sensor 15 from the casing 11. The terminal 16 can be used under vacuum, and for example, a hermetic or the like is used.

The controller 17 is a specific example of the temperature control unit of the present invention, and is connected to a control line, a current line, and a signal line drawn out of the casing 11 to the outside. The controller 17 transmits information to a heater 13 connected via a current line, a pulse tube refrigerator 14 connected via a control line, and a temperature sensor 15 connected via a signal line, as will be described later. Performs reading and various controls.
The power supply 18 supplies power to the heater 13 and the pulse tube refrigerator 14 via the controller 17. The temperature control system of the cold trap 10 is as shown in FIG. The pressure sensor 19 will be described later.
The cold trap 10 is configured as described above.

The turbo-molecular pump 20 is a well-known technology, and is a pump that disposes a large number of moving blades and a large number of fixed blades alternately, rotates the moving blade at an extremely high speed of tens of thousands of rpm, and moves and exhausts molecules. is there. There is an advantage that a clean vacuum can be obtained.
The cold trap 10 and the turbo molecular pump 20 constitute a vacuum exhaust device 100.

  Subsequently, the operation of the cold trap 10 and the turbo molecular pump 20 when operating the evacuation apparatus 100 will be described. In addition, assuming an exhaust system as shown in FIG. 4, a description will be given assuming that the vacuum chamber 30, the gate valve 40, the cold trap 10, and the turbo molecular pump 40 are connected to exhaust the inside of the vacuum chamber 10.

In the evacuation apparatus 100 having the above configuration, the cold trap 10 is operated together with the evacuation of the turbo molecular pump 20.
When the gas in the vacuum chamber 30 starts to be exhausted, the pressure of the gas in the vacuum chamber 30 starts to decrease. As the pressure of the gas in the vacuum chamber 30 decreases, the moisture in the vacuum chamber 30 evaporates into water vapor. These gases containing water vapor pass through the cold trap 10 via the gate valve 40.

In the cold trap 10, as shown in FIGS. 1 and 3, the controller 17 starts the operation of the pulse tube refrigerator 14 and feeds back a temperature measurement signal output from the temperature sensor 15, thereby causing the cold panel 12 to operate. Maintain at a given temperature.
For example, as an example of the predetermined temperature of the cold panel 12, a temperature within a range of 120K to 150K (−153 ° C. to −123 ° C.), which is an optimum temperature for freezing and collecting only steam, is selected and controlled. The water vapor is collected by freezing.
As a result, moisture in the vacuum chamber 30 is adsorbed, and molecules other than moisture are compressed to a high compression ratio by the turbo molecular pump 20 and exhausted.

Such a cold trap 10 has the following advantages.
For example, in the conventional GM type refrigerator, once operated, continuous operation was performed at a rated value regardless of the load. However, in the cold trap 10 of the present embodiment, the operation of the pulse tube refrigerator 14 is controlled by a cold panel. It is only necessary to set the electric power so as to have an optimum temperature according to the adsorption capacity of the power supply 10, and unnecessary power consumption can be avoided.

Further, the cold trap 10 is directly connected to the cold panel 12 by using the pulse tube refrigerator 14 for cooling, using the heater 13 for heating, or using the pulse tube refrigerator 14 and the heater 13 in combination. Both cooling and heating are possible, and it is possible to control a wide range of arbitrary temperature of 60K to 573K (−213 ° C. to 300 ° C.), and not only water vapor but also any gas (for example, Br ₂ , NH ₃ , Cl ₂ , CO ₂₎ , Etc.) can be selectively adsorbed.

  In the case where the entire cold panel 12 of the cold trap 10 is covered with ice and the adsorption efficiency is reduced and the exhaust speed is reduced, the following first method (for convenience, called the rapid regeneration method) and The cold panel 12 can be regenerated by removing ice from the cold panel 12 by a second method (for convenience, referred to as a slow regeneration method). Hereinafter, the first and second methods will be described.

Regarding the first method (rapid regeneration method) In this method, the condensed ice is rapidly heated to a high temperature to form all water vapor, exhausted and removed from the cold trap 10, and the cold panel 12 is rapidly regenerated. . Hereinafter, a description will be given in chronological order with reference to FIGS.

(1) As shown in FIG. The gate valve 40 provided between the vacuum chamber 30 and the cold trap 10 is closed.
(2) As shown in FIGS. 1 and 3, the controller 17 controls the pulse tube refrigerator 14 to stop operating.
(3) The controller 17 controls the heater 13 to heat the cold panel 12 to 300 ° C at a stretch. The controller 17 controls the temperature based on the temperature measurement signal output from the temperature sensor 15 so that the rise time is shortest.
(4) The vaporized steam is discharged from a regeneration exhaust port (not shown) provided in the body 11a of the casing 11. In addition, a vacuum pump (not shown) is connected downstream of the regeneration exhaust port, and the exhaust is performed at high speed.
(5) The controller 17 controls the pulse tube refrigerator 14 to restart the operation.
(6) As shown in FIG. 4, the gate valve 40 provided between the vacuum chamber 30 and the cold trap 10 is opened, and the evacuation of the vacuum chamber 40 by the turbo molecular pump 20 is continued.

  The adoption of such a rapid reproduction method has been difficult in the prior art. The expander of the conventional GM refrigerator has an abrasion-resistant seal made of a resin material. Therefore, the upper limit temperature is limited to 100 ° C. or lower. Recently, a material that can be regenerated at about 180 ° C. has appeared, but the structure cannot be essentially heated at a high temperature.

  On the other hand, in the present embodiment, in particular, the pulse tube expander of the pulse tube refrigerator 14 has no moving parts and is entirely made of metal. Thereby, the upper limit of the temperature is relaxed, and heating to 300 ° C. can be performed in a short time. As a result, the reproduction time can be significantly reduced.

Regarding the second method (slow regeneration method) In this method, during normal operation of the evacuation apparatus 100, ice frozen in the cold panel 12 is sublimated little by little into steam, and a turbo is discharged from the cold trap 10. In this case, the cold panel 12 is slowly and slowly regenerated by evacuating and removing the gas slowly through the molecular pump 20.

(1) As shown in FIG. 1, the controller 17 inputs a pressure measurement signal from a pressure sensor 19 (see FIG. 3) provided inside the vacuum chamber 30 (or the casing 11 of the cold trap 10). For example, it is assumed that the controller 17 determines that the pressure is 10 ⁻⁸ Pa based on a pressure measurement signal from the pressure sensor 19 (see FIG. 3).
(2) The controller 17 reads from a memory (not shown) the saturation temperature of water vapor corresponding to the pressure calculated from the pressure measurement signal. For example, the saturation temperature corresponding to 10 ⁻⁸ Pa is about 130K.

(3) The controller 17 controls the temperature of the cold panel 12 to be slightly lower than the saturation temperature. In this case, the controller 17 controls the temperature of the heater 13 (or the pulse tube refrigerator 14) so as to approach the target temperature by feedback-inputting the temperature measurement signal output from the temperature sensor 15. Here, it is assumed that the target temperature is, for example, about 125K which is lower than the saturation temperature 130K. Ice located directly in contact with the cold panel 12 does not exceed the saturation temperature, but ice located away from the cold panel 12 exceeds the saturation temperature.

(4) The ice that has reached the saturation temperature immediately sublimes to water vapor at this low temperature without liquefaction.
(5) Thereafter, the temperature of the cold panel 12 is gradually increased so as to approach the saturation temperature 130K, and the cold panel 12 is gradually regenerated. Here, as the temperature rise time, an optimal time may be registered in a memory (not shown) in advance by an experiment or the like.
If the temperature rise is too rapid, the degree of vacuum in the vacuum chamber 30 decreases due to an increase in water vapor molecules. Therefore, the controller 17 monitors a pressure value obtained from a pressure measurement signal output from the pressure sensor 19, and The temperature of the heater 13 (or the pulse tube refrigerator 14) is increased so that the pressure does not rise sharply, and if the pressure value increases (the degree of vacuum decreases), the heater 13 is stopped (or the pulse tube refrigerator). 14 to lower the cooling temperature).

In the present embodiment, the turbo molecular pump 20 is directly arranged in series downstream of the cold trap 10, but other forms can be adopted. FIGS. 5 and 6 are block diagrams of other evacuation devices.
For example, as shown in FIG. 5, the cold trap 10 may be connected upstream of the vacuum chamber 30, and the turbo molecular pump 20 may be connected downstream.

  In addition, as shown in FIG. 6, a plurality of vacuum evacuation devices 100 may be attached to the vacuum chamber 30 in parallel. The number of connections is determined by the size of the vacuum chamber 30.

  As described above, according to the cold trap 10 or the evacuation device 100 of the present invention, the surface temperature of the cold panel 12 can be kept constant at an optimum temperature for adsorption by using the optimum power. For this reason, running power can be greatly reduced because no extra power is required by heating the heater 13.

  In addition, since the temperature of the cold panel 12 can be controlled from a minimum of 60K (−213 ° C.) to a maximum of 573K (+ 300 ° C.), in addition to water vapor, selective adsorption at an optimal temperature according to the adsorption characteristics of a gas to be adsorbed can be performed. This makes it possible to effectively control the release of water in a short time during regeneration.

  Further, since the cold panel 12 is provided with the heater 13 serving as a heating means, the cold panel 12 can be uniformly and quickly heated, and the outgas from the components of the heater 13 is not discharged into the vacuum chamber 30. High clean environment can be provided.

  In addition, a highly efficient and compact pulse tube refrigerator 14 was employed as the refrigerator. The pulse tube expander built in the pulse tube refrigerator 14 has no moving parts such as non-metallic sliding materials such as resin, and is entirely composed of metal parts, and can control the heating temperature during the regeneration process. It can be set to be much higher than a GM refrigerator having a section, and the reliability against heat shock can be improved.

Further, since the surface material of the cold panel 12 is made of pure titanium, copper, or a copper alloy having a higher thermal conductivity than stainless steel in a low temperature range, the surface temperature distribution of the cold panel 12 is made uniform as compared with a commonly used stainless steel material. As a result, the effective surface area of the cold panel 12 can be increased, and the adsorption speed can be increased.
In addition, a protection layer is formed on a cold panel made of copper or a copper alloy so as not to generate rust due to water vapor, thereby improving corrosion resistance and extending the life of the apparatus.

  Also, of the surface of the cold panel 12, the trapping surface is made a plain ground surface to increase the surface area capable of adsorbing gas, and the surface area and emissivity of the outer surface other than the trapping surface are reduced, so that from the room temperature side. The amount of heat entering can be reduced, and an efficient cold trap can be obtained.

  In addition, since a cold trap 10 for discharging gas after freezing and collecting water molecules and a turbo-molecular pump 20 for compressing and discharging gas molecules are provided, according to the load on the cold panel 12 during gas adsorption. Since the temperature can be controlled and the pulse tube refrigerator 14 can be stopped at the time of regeneration and the heater 13 can be uniformly heated at a high temperature, the vacuum exhaust device having a high operation rate and low running cost can be used in combination with the turbo molecular pump 20. 100 can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side sectional view of the cold trap of the best form for implementing this invention, and the evacuation apparatus which consists of a cold trap and a turbo molecular pump. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block configuration diagram of a vacuum evacuation apparatus according to a best mode for carrying out the present invention. It is a block diagram of a temperature control system. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block configuration diagram of a vacuum evacuation apparatus according to a best mode for carrying out the present invention. FIG. 7 is a block configuration diagram of another evacuation apparatus according to the best mode for carrying out the present invention. FIG. 7 is a block configuration diagram of another evacuation apparatus according to the best mode for carrying out the present invention.

Explanation of reference numerals

100: Vacuum exhaust device 10: Cold trap 11: Casing 11a: Body 11b: Flange 12: Cold panel 12a: Outer peripheral panel 12b: Inner peripheral panel 12c: Supporting part 13: Heater 14: Pulse tube refrigerator 14a: Cooling end 14b : Expander 14c: Compressor 15: Temperature sensor 16: Terminal 17: Controller 18: Power supply 19: Pressure sensor 20: Turbo molecular pump
30: vacuum chamber 40: gate valve

Claims (9)

A casing,
A cold panel installed in the casing,
Heating means for heating the cold panel;
A refrigerator having a compressor, an expander, and a cooling end, wherein the cooling end is disposed at least inside the casing while being thermally connected to the cold panel;
Temperature measurement means for measuring the temperature of the cold panel;
Heating means, a temperature control means to which the refrigerator and the temperature measurement means are connected,
A cold trap with
The temperature control unit controls the refrigerator or the heating unit based on the temperature of the cold panel measured by the temperature measurement unit so that the temperature of the cold panel is set to a predetermined temperature. The cold trap according to claim 1,
A cold trap, wherein a temperature control range of the cold panel ranges from a minimum of 60K (−213 ° C.) to a maximum of 573K (+ 300 ° C.). In the cold trap according to claim 1 or 2,
The said heating means is built in the cold panel, The cold trap characterized by the above-mentioned. In the cold trap according to any one of claims 1 to 3,
The said expander is a pulse tube expander, The cold trap characterized by the above-mentioned. In the cold trap according to any one of claims 1 to 4,
A cold trap, wherein the cold panel is made of pure titanium having a high thermal conductivity in a low temperature range. In the cold trap according to any one of claims 1 to 4,
A cold trap, wherein the cold panel is made of copper or a copper alloy having a high thermal conductivity in a low temperature range. The cold trap according to claim 6,
A cold trap, wherein a protective layer for improving corrosion resistance is formed on a surface of the cold panel. In the cold trap according to any one of claims 1 to 7,
The cold panel is characterized in that the cold panel increases the surface area of a trap surface for freezing and collecting water molecules, and makes the outer surface other than the trap surface a glossy surface having a low emissivity. The cold trap according to any one of claims 1 to 8, which causes the remaining gas obtained by freeze-trapping water molecules to flow out,
A turbo molecular pump for exhausting gas flowing out of the cold trap,
A vacuum evacuation device comprising:

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