JP4182905B2 - Cold trap and vacuum exhaust - Google Patents

Description

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

An example of a vacuum exhaust device that exhausts the inside of a vacuum chamber is a turbo molecular pump. This turbo molecular pump has different exhaust performance depending on the molecular weight (molecular size) of gas molecules to be discharged. It is particularly difficult to evacuate water vapor having a small molecular weight. For example, when the gas in the vacuum chamber is exhausted to about 10 ⁻⁶ Pa to 10 ⁻¹² Pa by a turbo molecular pump, the residual gas in the vacuum chamber is Most of it is water vapor. If such water vapor remains in the vacuum chamber, the degree of vacuum and the vacuum environment are adversely affected.

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 gas to pass in contact with a surface cooled to a very low temperature (hereinafter referred to as a cold panel), collects the water vapor contained in the passing gas by cooling it to freeze it on ice. It is an apparatus, and a vacuum environment with less water vapor can be obtained in the vacuum chamber.
By removing the water vapor from the cold trap, the gas from which the water vapor has been removed in advance is allowed to flow into the turbo molecular pump, so that the exhaust speed of the vacuum chamber can be improved. In addition, the cold trap can appropriately collect other gases (for example, Br ₂ , NH ₃ , Cl ₂ , CO _2, etc.) by appropriately setting the cooling temperature.

  Originally, both the change from solid (ice) to gas (water vapor) and the change from gas (water vapor) to solid (ice) are both sublimated. 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.

There are various conventional techniques for such a cold trap. As another conventional technique, for example, the invention described in Patent Document 1 (turbo molecular pump) or Patent Document 2 (cold trap and vacuum exhaust apparatus) 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 (paragraph numbers 0022 to 0036, FIGS. 1 to 4) JP-A-11-294330 (paragraph numbers 0032 to 0049, FIGS. 1 to 3)

  The water vapor exhaust rate and adsorption amount in the molecular flow region increase in proportion to the surface area of the cold panel. However, if the surface area is simply increased, (1) the exhaust resistance increases, (2) the amount of heat penetration due to radiation from the casing increases, and the power consumption of the refrigerator increases to compensate for this. there were.

  Accordingly, an object of the present invention, which has been made in view of the above problems, is to provide a cold trap that realizes low power consumption and high-speed exhaust gas and increases an adsorption capacity, and a turbo molecular pump in a cold trap having such advantages. It is providing the vacuum exhaust apparatus which used together.

In order to solve the above problems, the cold trap of the invention according to claim 1 of the present invention provides:
A casing,
A cold panel installed in the space inside the casing;
A refrigerator having a compressor, an expander, and a cooling end, and arranged at least in the interior space of the casing with the cooling end being thermally connected to the cold panel;
With
The cold panel is a corrugated cylindrical body having a substantially cylindrical shape and a cylindrical wall surface that is uneven along the radial direction, and a plurality of corrugated cylindrical bodies having different radii are coaxially arranged in multiple layers and formed over a plurality of layers, and The opening of the inner corrugated cylindrical body is located in the middle of the opening of the outer corrugated cylindrical body .

  According to this configuration, since the surface area of the trap surface of the cold panel for freezing and collecting water molecules is increased without changing the diameter of the cylinder, an increase in adsorption capacity and high-speed exhaust can be realized. Further, since the surface area is increased so as not to face the gas flow path direction, the exhaust conductance is not increased, and as a result, low power consumption is also realized.

In addition, according to this configuration, the mounting space of the circular cross section can be effectively utilized mainly by arranging the undulating cylinders on the same axis in multiple layers and optimizing the pitch between the adjacent undulating cylinders. The trap surface area can be increased while preventing an increase in exhaust conductance as much as possible.

In addition, according to this configuration, the outer corrugated cylindrical body functions as a shielding wall, and the surface area of the inner corrugated cylindrical panel facing the inner wall of the multi-layered piping pipe wall or vacuum chamber can be reduced. , The amount of intrusion heat proportional to the fourth power of the temperature difference and the surface area ratio can be reduced.

The cold trap of the invention according to claim 2 of the present invention is
The cold trap of claim 1 ,
The cold panel is made of pure titanium having a high thermal conductivity in a low temperature region.

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

The cold trap of the invention according to claim 3 of the present invention is
The cold trap of claim 1 ,
The cold panel is made of copper or a copper alloy having a high thermal conductivity in a low temperature region.

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

The cold trap of the invention according to claim 4 of the present invention is
The cold trap according to claim 3,
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 that prevents gas from coming into contact with copper or a copper alloy, corrosion of the surface of the copper or copper alloy can be prevented.

The cold trap of the invention according to claim 5 of the present invention is
In the cold trap as described in any one of Claims 1-4 ,
The expander is a pulse tube expander.

  According to this configuration, the expander of the pulse tube refrigerator (hereinafter simply referred to as the pulse tube expander) does not have a movable part such as a non-metallic sliding material unlike the GM type refrigerator, and is all made of metal. Therefore, the heating temperature during the regeneration process can be set to be significantly higher than that of the GM refrigerator having a movable part, and the reliability against heat shock can be improved.

The cold trap of the invention according to claim 6 of the present invention is
In the cold trap as described in any one of Claims 1-5 ,
Heating means for heating the cold panel,
And temperature measuring means for measuring the temperature of the cold panel,
A temperature control means to which the heating means, the refrigerator and the temperature measurement means are connected;
With
The temperature control means, based on the temperature of the cold panel temperature measuring means has measured, and controlling the refrigerator or the heating means to the temperature of the cold panel to a predetermined temperature.

  According to this configuration, the temperature of the cold panel can be optimally selected by selecting an effective temperature according to the gas adsorption characteristics during adsorption, and effective in releasing moisture during the regeneration process. The temperature can be selected and controlled so that the temperature of the trap surface of the cold panel is optimized, and the surface temperature of the cold panel (trap surface) can be set to an arbitrary temperature optimum for adsorption / regeneration.

The cold trap of the invention according to claim 7 of the present invention is
The cold trap according to claim 6 ,
The heating means is built in the cold panel.

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

An evacuation apparatus according to an eighth aspect of the present invention provides:
The cold trap according to any one of claims 1 to 7 , wherein the remaining gas obtained by freezing and collecting water molecules is discharged.
A turbo molecular pump that exhausts the gas flowing out of the cold trap;
It is characterized by providing.

  According to this configuration, the cold panel has a cold panel with an increased surface area of the trap surface to increase the adsorption capacity for freezing and collecting water molecules. A low-pressure evacuation apparatus can be provided.

  According to the present invention as described above, a cold trap that achieves low power consumption and high-speed exhaust and increases the adsorption capacity, and a vacuum exhaust device that uses a turbo molecular pump in combination with a cold trap having such advantages. Can be provided.

  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 the cold trap of the present embodiment, and a vacuum exhaust apparatus including a cold trap and a turbo molecular pump. FIG. 2 is an explanatory view of a cold panel, FIG. 2 (a) is a side view of the cold panel and the pulse tube refrigerator, and FIG. 2 (b) is a plan view of the cold panel. 3 and 4 are explanatory diagrams of another cold panel, FIG. 5 is a block diagram of the vacuum evacuation device of this embodiment, FIG. 6 is a block diagram of a temperature control system, and FIG. 7 is a block configuration of the vacuum evacuation device of this embodiment. FIG.

As shown in FIGS. 1 and 5, the vacuum exhaust apparatus 100 of this embodiment includes a cold trap 10 and a turbo molecular pump 20. FIG. 1 shows a specific configuration, and FIG. 5 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 portion 16, a controller 17, and a power source 18.

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

The cold panel 12 includes an outer peripheral panel 12a, an inner peripheral panel 12b, and a support portion 12c.
A support portion 12c such as a bar or a pipe is attached to the inside of the outer peripheral panel 12a. The inner peripheral panel 12b is sized 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 approximately the center in the casing 11.

  The outer peripheral panel 12a and the inner peripheral panel 12b are formed in a substantially cylindrical shape as a waved cylindrical body having a cylindrical wall surface that is uneven in the radial direction, and increases the surface area of the trap surface. Specifically, the shape is as shown in FIG. Such a corrugated cylinder has an increased surface area compared to a simple cylinder. For example, as shown in the enlarged portion of FIG. 2, when the corrugated cylindrical body is an equilateral triangle with an angle of 60 °, the length of a is simply a cylinder and the length of 2a is corrugated cylindrical. However, the surface area increases more than a simple cylindrical body, although there is an increase or decrease depending on the angle. Since the molecular flow comes into contact with the trap surface having an increased surface area in this way, water molecules can be easily collected. Thus, the molecules can be efficiently frozen and collected by increasing the surface area of the trap surface.

  In the cold panel 12, the axial length of the inner peripheral panel 12b is shorter than the axial length of the outer peripheral panel 12a, and the upper and lower openings of the inner peripheral panel 12b are located above and below the outer peripheral panel 12a. It is made to be located inside the opening. This narrows the field of view from the body 11a of the casing 11 (further, although not shown, the pipe wall or the inner wall of the vacuum chamber located upstream or downstream) to the inner peripheral panel 12b, that is, between the casing 11 and the inner peripheral panel 12b. The outer peripheral panel 12a shields the gap so that radiant heat from the inner peripheral wall surface of the body 11a of the casing 11 does not reach the inner peripheral panel 12b.

For example, considering that there is no outer peripheral panel 12a and the inner peripheral panel 12b directly faces the inner peripheral wall surface of the trunk portion 11a, heat radiation reaches the inner peripheral panel 12b from the trunk portion 11a, and the cooling capacity is reduced. Conversely, if the outer panel 12a is shielded as described above, the surface area of the inner panel 12b where the radiant heat reaches directly opposite the body 11a of the casing 11 at room temperature can be reduced. The amount of intrusion heat proportional to the fourth power of the difference and the surface area ratio can be reduced.
By adopting such a multiple structure, the amount of intrusion heat due to external radiation can be reduced. In addition, although it is a double structure in this embodiment, the effect of reducing the amount of intrusion heat due to radiation from the outside can be further increased by configuring it to be triple or more.

The cold panel 12 is manufactured using pure titanium having a thermal conductivity higher than that of stainless steel at an extremely low temperature of about 70K (−203 ° C.). By using the cold panel 12 made of pure titanium, 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 an extremely low temperature range of about 70K (−203 ° C.). Since the heat conductivity is thus large, 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, since the surface temperature distribution of the entire cold panel 12 becomes uniform and does not become a non-uniform temperature distribution unlike a stainless material having a small thermal conductivity that is usually used, the effective surface area of the cold panel 12 can be increased. It is possible to collect water molecules on the entire surface of the cold panel 12.

  Furthermore, the cold panel 12 made of copper or a copper alloy is formed 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, with respect to copper or copper alloy which is easily corroded (that is, oxidized), the corrosion resistance is improved and consideration is given so that patina or the like is not generated by gas (especially water vapor). Due to the thermal conductivity of copper or copper alloy and the corrosion resistance of nickel, it is suitable for the specific use of the cold trap 10 (freezing and collection of water molecules).

Furthermore, the inner surface (trap surface) of the outer peripheral panel 12a and the inner peripheral panel 12b may be configured to be formed into a ground shape by, for example, blasting or peening, and to increase the surface area. In addition, it is good also as an uneven surface in which many protrusions were formed, if the surface area could be expanded.
Further, the outer surface of the outer peripheral panel 12a and the inner peripheral panel 12b (the surface opposite to the body 11a of the casing 11) is configured to have a mirror surface (glossy surface) with as low an emissivity as possible to reduce the emissivity. Thereby, the amount of heat entering from the normal temperature side can be further reduced.

The heater 13 is one specific example of the heating means of the present invention. For example, the heater 13 is a cylindrical sheet heater that is hermetically sealed in a sandwich shape inside the outer peripheral panel 12a and the inner peripheral panel 12b of the cold panel 12. The current line and the insulating part are configured not to be exposed from the outer peripheral surface panel 12a of the cold panel 12 and the trap surface of the inner peripheral surface panel 12b.
In this embodiment, as shown in the enlarged portion of FIG. 2B, for example, the outer peripheral panel 12a has a two-layer structure of an outer panel 121 and an inner panel 122, and a heater is provided between the outer panel 121 and the inner panel 122. 13 is arranged.
The heater 13 may be a linear heater such as a sheathed heater as long as it can be installed almost uniformly on the outer peripheral panel 12a and the inner peripheral panel 12b of the cold panel 12. Moreover, when manufacturing the outer peripheral surface panel 12a and the inner peripheral surface panel 12b of the cold panel 12 as a casting, it may be a cast-in heater and various heaters can be employed.

  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 the Stirling cycle of the expander 14b and the compressor 14c. In an ordinary Stirling type refrigerator, the expander is mechanically constituted by a piston and a cylinder, but in the pulse tube refrigerator 14, there is no moving part, and the gas (gas piston) in the pulse tube (not shown) is Have a role.

The pulse tube refrigerator 14 is mounted such that the compressor 14c and the expander 14b are attached to 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. It is done.
The outer peripheral 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 path of the outer peripheral panel 12a, the support portion 12c, and the inner peripheral panel 12b. 14 to cool.

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

The controller 17 is a specific example of the temperature control means of the present invention, and is connected to a control line, a current line, and a signal line drawn from the casing 11 to the outside. The controller 17 stores information as described later for the heater 13 connected via the current line, the pulse tube refrigerator 14 connected via the control line, and the temperature sensor 15 connected via the signal line. Read and perform 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 in this way.

The turbo molecular pump 20 is a well-known technology, but is a pump that alternately arranges a large number of moving blades and a large number of fixed blades, rotates the moving blades at an extremely high speed of tens of thousands of rpm, moves the molecules, and exhausts them. 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.

In such a cold trap 10, in particular, since the surface area of the cold panel 12 has increased, the surface area of the trap surface of the cold panel that freezes and collects water molecules can be increased to realize increased adsorption capacity and high-speed exhaust. .
In addition, since the surface area is increased so as not to face the gas flow path direction, the exhaust conductance is not increased, and a structure that suppresses heat intrusion due to radiation from the casing as much as possible is adopted. Low power consumption is also realized.

Various shapes other than the present invention can be considered for the shape of the cold panel 12, and as shown in FIG. 3, the length of the outer peripheral panel 12a and the length of the inner peripheral panel 12b of the cold panel 12 arranged coaxially are the same. The upper and lower openings of the outer peripheral panel 12a and the upper and lower openings of the inner peripheral panel 12b may be positioned at the same height. Compared with the configuration shown in FIG. 2, the area where the inner peripheral panel 12b faces the body 11b of the shield 11 at room temperature increases, the amount of intrusion heat due to radiant heat increases, and the cooling capacity slightly decreases in this respect. However, there is still an advantage that the total surface area of the cold panel 12 is increased and the ability to collect water molecules is increased.

Furthermore, as another example of the cold panel 12 other than the present invention, for example, as shown in FIG. 4, a single cold panel 12 may be used. Even in this case, the surface area of the panel is increased about twice as compared with a simple cylindrical shape, and the collection capacity is enhanced as compared with a simple cylindrical cold panel of the prior art. In addition, since the surface area of the cold panel facing the room temperature surface in the field of view from the room temperature surface is the same as in the case of a simple cylindrical shape, the amount of intrusion heat due to radiation does not increase compared to a simple cylindrical cold panel.

  Next, operations of the cold trap 10 and the turbo molecular pump 20 when operating the vacuum exhaust apparatus 100 will be described. It is assumed that an exhaust system as shown in FIG. 7 is assumed, and 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 vacuum exhaust apparatus 100 having the above-described configuration, the cold trap 10 is operated together with the exhaust 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 gas pressure in the vacuum chamber 30 decreases, the moisture in the vacuum chamber 30 vaporizes into water vapor. The gas containing water vapor passes through the cold trap 10 through the gate valve 40.

In the cold trap 10, as shown in FIGS. 1 and 6, the controller 17 starts the operation of the pulse tube refrigerator 14 and feeds back the temperature measurement signal output from the temperature sensor 15. Maintain at a predetermined temperature.
For example, as an example of the predetermined temperature of the cold panel 12, a temperature within a range of 120 K to 150 K (−153 ° C. to −123 ° C.) which is an optimum temperature for freezing and collecting only water vapor is selected and controlled. Water vapor is frozen and collected.
Thereby, moisture in the vacuum chamber 30 is adsorbed, and molecules other than moisture are compressed by the turbo molecular pump 20 to a high compression ratio and exhausted.

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

In addition, the cold trap 10 directly uses the pulse tube refrigerator 14 for cooling, uses the heater 13 for heating, or uses the pulse tube refrigerator 14 and the heater 13 in combination, so that the cold trap 12 is directly attached to the cold panel 12. Both cooling and heating are possible, and the temperature can be controlled to an arbitrary temperature in a wide range of 60K to 573K (−213 ° C. to 300 ° C.), and not only water vapor but also an arbitrary gas (for example, Br ₂ , NH ₃ , Cl ₂ , CO _2). Etc.) can be selectively adsorbed.

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

About 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 from the inside of the cold trap 10, and the cold panel 12 is rapidly regenerated. . Hereinafter, it will be described in time series with reference to FIG. 1, FIG. 6, and FIG.

(1) As shown in FIG. 7, the gate valve 40 provided between the vacuum chamber 30 and the cold trap 10 is closed.
(2) As shown in FIGS. 1 and 6, the controller 17 performs control so as to stop the operation of the pulse tube refrigerator 14.
(3) The controller 17 controls the heater 13 to heat the cold panel 12 to 300 ° C. at once. Based on the temperature measurement signal output from the temperature sensor 15, the controller 17 controls the temperature so that the rise time is the shortest.
(4) Vaporized water vapor is discharged from a regeneration exhaust port (not shown) provided in the body 11a of the casing 11. A vacuum pump (not shown) is connected downstream of the regeneration exhaust port to exhaust at high speed.
(5) The controller 17 controls to restart the operation of the pulse tube refrigerator 14.
(6) As shown in FIG. 7, the gate valve 40 provided between the vacuum chamber 30 and the cold trap 10 is opened, and evacuation in the vacuum chamber 40 by the turbo molecular pump 20 is continued.

  Adopting such a rapid regeneration method has been difficult with the prior art. Since the conventional expander of the GM refrigerator has a wear-resistant seal made of a resin material, the upper limit temperature is limited to 100 ° C. or less. Recently, a material that can be regenerated at about 180 ° C. has appeared, but it is essentially a structure that cannot be heated at high temperatures.

  On the other hand, in this embodiment, in particular, the pulse tube expander of the pulse tube refrigerator 14 has no movable part and is entirely made of metal. Thereby, the upper limit of temperature is relieved and it can heat to 300 degreeC in a short time. Thereby, the reproduction time can be greatly shortened.

About the second method (slow regeneration method) In this method, during the normal operation of the vacuum exhaust apparatus 100, ice frozen on the cold panel 12 is gradually sublimated to water vapor, and the turbo is discharged from the cold trap 10 into the turbo. The exhaust is removed little by little through the molecular pump 20, and the cold panel 12 is regenerated slowly (slowly).

(1) As shown in FIG. 1, the controller 17 inputs a pressure measurement signal from a pressure sensor 19 (see FIG. 6) 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 10 ⁻⁸ Pa based on the pressure measurement signal from the pressure sensor 19 (see FIG. 6).
(2) The controller 17 reads the water vapor saturation temperature corresponding to the pressure calculated from the pressure measurement signal from a memory (not shown). 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 a little 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 that the temperature measurement signal output from the temperature sensor 15 is fed back and approaches the target temperature. Here, the target temperature is assumed to be about 125K, which is lower than the saturation temperature 130K, for example. Ice at a position in direct contact with the cold panel 12 does not exceed the saturation temperature, but ice at a location away from the cold panel 12 exceeds the saturation temperature.

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

In the present embodiment, the turbo molecular pump 20 is directly arranged in series downstream of the cold trap 10, but other forms may be adopted. 8 and 9 are block configuration diagrams of other evacuation apparatuses.
For example, as shown in FIG. 8, 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. 9, a large number of vacuum exhaust devices 100 may be attached in parallel to the vacuum chamber 30. 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 vacuum exhaust apparatus 100 of the present invention, the corrugated shape has a small area in the same direction as the flow direction and a large area in the flow direction and the vertical direction. The cylindrical panel increases the surface area of the cold panel 12 and does not increase the fluid resistance (exhaust conductance) when the gas flows, increasing the adsorption capacity despite low power consumption and high pumping speed. A cold trap to be used. Furthermore, as a vacuum exhaust system using a turbo molecular pump in combination with a cold trap having such advantages, the vacuum exhaust capacity could be increased.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view of a vacuum trap of the best mode for carrying out the present invention, and an evacuation apparatus including a cold trap and a turbo molecular pump. It is explanatory drawing of a cold panel, Fig.2 (a) is a side view of a cold panel and a pulse tube refrigerator, FIG.2 (b) is a top view of a cold panel. It is explanatory drawing of another cold panel. It is explanatory drawing of another cold panel. It is a block block diagram of the vacuum exhaust apparatus of the best form for implementing this invention. It is a block diagram of a temperature control system. It is a block block diagram of the vacuum exhaust apparatus of the best form for implementing this invention. It is a block block diagram of the other vacuum exhaust apparatus of the best form for implementing this invention. It is a block block diagram of the other vacuum exhaust apparatus of the best form for implementing this invention.

Explanation of symbols

100: Vacuum exhaust device 10: Cold trap 11: Casing 11a: Body 11b: Flange 12: Cold panel 12a: Outer panel 12b: Inner panel 12c: Support section 121: Outer panel 122: Inner panel 13: Heater 14: Pulse Tube refrigerator 14a: Cooling end 14b: Expander 14c: Compressor 15: Temperature sensor 16: Terminal unit 17: Controller 18: Power supply 19: Pressure sensor 20: Turbo molecular pump
30: Vacuum chamber 40: Gate valve

Claims (8)

A casing,
A cold panel installed in the space inside the casing;
A refrigerator having a compressor, an expander, and a cooling end, and arranged at least in the interior space of the casing with the cooling end being thermally connected to the cold panel;
With
The cold panel is a corrugated cylindrical body having a substantially cylindrical shape and a cylindrical wall surface that is uneven along the radial direction, and a plurality of corrugated cylindrical bodies having different radii are coaxially arranged in multiple layers and formed over a plurality of layers, and A cold trap, wherein an opening portion of an inner corrugated cylindrical body is positioned inward of an opening portion of an outer corrugated cylindrical body . In the cold trap according to claim 1,
The cold panels, cold trap, wherein to Rukoto and material is large pure titanium thermal conductivity at low temperature range. The cold trap of claim 1 ,
The cold panel is made of copper or a copper alloy having a high thermal conductivity in a low temperature region . The cold trap according to claim 3 ,
The cold trap is characterized in that a protective layer for improving corrosion resistance is formed on the surface of the cold panel. In the cold trap as described in any one of Claims 1-4 ,
The expander, a cold trap, wherein the pulse tube expander der Rukoto. In the cold trap as described in any one of Claims 1-5 ,
Heating means for heating the cold panel ;
Temperature measuring means for measuring the temperature of the cold panel;
A temperature control means to which the heating means, the refrigerator and the temperature measurement means are connected;
With
The temperature control means controls the refrigerator or the heating means so that the temperature of the cold panel is a predetermined temperature based on the temperature of the cold panel measured by the temperature measurement means . The cold trap according to claim 6 ,
It said heating means, a cold trap, wherein Rukoto incorporated in the cold panel. The cold trap according to any one of claims 1 to 7, wherein the remaining gas obtained by freezing and collecting water molecules is discharged.
A turbo molecular pump that exhausts the gas flowing out of the cold trap;
An evacuation apparatus comprising:

Images