JPH0386225A - Vacuum device - Google Patents

Abstract

PURPOSE:To reduce the gas discharging amount to the value corresponding to the length almost equal to the mim. length of bellows by contacting the bellows to set a vacuum pump, etc., near a vacuum vessel keeping the vacuum state when high temp. baking is not carried out. CONSTITUTION:The vacuum vessel 1, the vacuum pump 4 evacuating the vacuum vessel 1, and the vacuum gauge displaying the degree of vacuum in the vessel 1 are provided to intermittently carry out high temp. baking or to generate high magnetic field. The vacuum pump and the vacuum gauge 4, etc., are connected to the vessel 1 through the bellows, and the bellows 10 is stretched during high temp. baking or high magnetic field generation in the vessel 1 in order to locate the vacuum pump and the vacuum gauge 4, etc., to be far from the vessel 1. When the high temp. baking is not carried out of the high magnetic field is not generated, the bellows 10 is contracted keeping the vacuum state to allow the setting of the vacuum pump and the vacuum gauge 4, etc., near the vessel 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a vacuum apparatus that performs intermittent high-temperature baking or generates a high magnetic field.

(Conventional technology) In order to achieve ultra-high vacuum by reducing the amount of gas released from the materials of the vacuum container and vacuum equipment facing the vacuum when vacuum containers and equipment for ultra-high vacuum are evacuated. 3. Perform the operation ``heating and baking''. When the material of the vacuum container or vacuum device is stainless steel, high-temperature baking of 300° C. or higher is often performed, and this is called "high-temperature baking."

A typical vacuum device consists of at least a vacuum container that maintains a vacuum state, a vacuum pump that moves the vacuum container from atmospheric pressure to a vacuum state, and a vacuum gauge that measures the degree of vacuum (pressure). In addition, vacuum equipment generally performs so-called "high temperature baking" to obtain the best possible vacuum (i.e., low pressure) to reduce the amount of outgassing of the material facing the vacuum of the vacuum vessel, or Some applications of vacuum equipment generate high magnetic fields. However, in general, vacuum pumps (particularly mechanical vacuum pumps such as turbomolecular pumps) and vacuum gauges use organic materials due to their structure, and their operating temperature is limited to 150℃ to 200℃ or less. Furthermore, the magnetic field is generally used in a weak magnetic field of several tens of Gauss or less. Therefore, there is a problem that if a vacuum pump, a vacuum gauge (for example, an ion gauge), etc. is exposed to high temperatures of 300° C. or higher or used in a strong magnetic field of several 10 Gauss or higher, there is a very high possibility that it will be damaged.

Therefore, conventionally, as shown in Fig. 9, a connecting pipe (3) of an appropriate length is installed in the connecting port (2) of the vacuum container (1), and a vacuum pump, etc. (including a vacuum gauge, etc.) ( 4)
Connect. In addition, in Fig. 9, connection port (2)
, the connecting pipe (3) and the vacuum pump, etc. (4) are connected in this way by sandwiching a vacuum sealing gasket (not shown) between the vacuum flanges attached to each, and tightening bolts and nuts. When set to , the vacuum pump, etc.
Since 4) is installed at a location away from the vacuum container (1), it is not exposed to high temperatures or high magnetic fields outside of the range of high temperature baking (or high magnetic field) of the vacuum container (1) @ (5) Therefore, there is no possibility that the vacuum pump etc. (4) will be damaged. Note that the high temperature generator and the high magnetic field generator are not shown in Figure 9. Also, temperature (especially the amount of heat transferred by heat conduction) is inversely proportional to the distance from the place where the temperature is generated, and the strength of the magnetic field is inversely proportional to the distance from the place where the magnetic field is generated. It is inversely proportional to the square of the distance from the source, so the further away you are from the place where they occur.

The temperature drops and the magnetic field weakens. However, in the case of Figure 9, the vacuum pump etc. (4) is connected to the vacuum container (1) via the connecting tube (3), so the conductance (reciprocal of the resistance) of the connecting tube (3) subject to restrictions. That is,
The conductance of the connecting pipe (3) becomes smaller as the connecting pipe (3) becomes longer, so in the case of a vacuum pump, the ability to actually evacuate the vacuum container (1) (this is called the "effective pumping speed")
) becomes smaller.

In addition, in the case of a vacuum gauge, there is a problem that the correct degree of vacuum (pressure) within the vacuum container (1) cannot be measured (generally, the gauge will show a slightly higher pressure). however,
When baking a vacuum container (1) at a high temperature or generating a high magnetic field in a vacuum device, it is important to first prevent damage to the vacuum pump, etc. (4), so see Figure 9. Place the vacuum pump (4) into the vacuum container (1) as shown in
It will be installed at a location far away from the Therefore, in this case, the current situation is that the vacuum pump etc. (4) has no choice but to accept the conductance limitations of the connecting pipe (3). However, when the vacuum container (1) is not subjected to high temperature baking or does not generate a high magnetic field, the vacuum pump etc. (4) is placed as close as possible to the vacuum container (1), as shown in FIG. It is desirable to connect directly to the connection port (2) of the vacuum vessel (1). If you do this, there is no connecting pipe (3), so the vacuum pump etc. (4) will be connected to the connecting pipe (3).
However, it is not possible to perform high temperature baking of the vacuum container (1) or generate a high magnetic field in the vacuum device (it becomes impossible). Become.

Therefore, while completing the present invention, it was considered to use a bellows (10) instead of the connecting pipe (3) as shown in FIGS. 7 and 8. In this way, the vacuum container (
The position of the vacuum pump (4) can be freely changed without breaking the vacuum of (1). However, the bellows (1
0) has the disadvantage that even if the length is shortened, the surface area of the part in contact with the vacuum is larger due to the unevenness (or peaks and valleys) compared to 1 normal pipes, so the amount of gas released is large. Shigashi,
If a large amount of released gas can be tolerated, this is an embodiment of the present invention.

(Problems to be Solved by the Invention) The means shown in Figs. 9 and 10 above require breaking the vacuum in the vacuum container, and the means shown in Figs. 7 and 8 have the disadvantage that the amount of released gas increases. .

The present invention has been made in view of the above-mentioned problems, and when the bellows is shortened to its shortest length without losing its function, the amount of gas released can be reduced to a normal length approximately equal to the shortest length of the bellows. The purpose is to provide a vacuum device that can reduce the value to that of a tube.

[Structure of the invention]

(Means for Solving Problem R) In order to achieve the above object, in the present invention, when attaching a vacuum pump etc. (including a vacuum gauge etc.) to a vacuum container, a bellows (bellows can be broadly classified depending on the manufacturing method) is used. They can be classified into molded bellows and welded bellows, but here we will explain welded bellows, which have a large amount of expansion and contraction.Also, so-called "flexible tubes" made up of long bellows are also included in this bellows category. ). When the vacuum container performs high-temperature baking or generates a high magnetic field, extend the bellows and install the vacuum pump, etc., away from the vacuum container and place it outside the range of high-temperature baking (or high magnetic field). .

Further, an inner tube having a length approximately equal to the shortest length of the bellows is rounded at one end of the bellows, and when the bellows is contracted, the free end of the inner tube is airtightly connected to a vacuum holding part installed at the other end of the bellows. The abutment provides a vacuum seal, allowing the bellows to be isolated from the vacuum region within the inner tube.

(Function) In this way, in the former case (when the bellows is extended), the vacuum pump, etc. will not be exposed to high temperatures or high magnetic fields, so there will be no risk of damage to the vacuum pump, etc. (However, in this case, the vacuum pump, etc. will be installed at a location far from the vacuum container, so it will be subject to the restriction of the conductance of the bellows. However, the first priority is to prevent damage to the vacuum pump, etc., and the conductance of the bellows will be limited. On the other hand, in the latter case (when the bellows is shortened), when the vacuum container is not subjected to high-temperature baking or when a high magnetic field is not generated, the bellows is shortened and the bellows is internalized by the inner tube. By isolating it from the vacuum region inside the tube, there is no gas released from the bellows, leaving only the amount of gas released from the inner tube. Furthermore, since a vacuum pump, etc. can be installed close to the vacuum container without breaking the vacuum, the restriction on the conductance of the bellows can be reduced to the minimum, and the functions of the vacuum pump, etc. can be fully demonstrated. can.

Embodiment 1 Next, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. Components having the same functions as those in FIGS. 7 to 10 are given the same reference numerals and their explanations will be omitted. In Figures 1 and 2, connection port (2) of vacuum vessel (1)
Attach a bellows (10) to the bellows, and connect a vacuum pump, etc. (including a vacuum gauge, etc.) (4) to it. (In Figures 1 and 2, the connections between the connection port (2), bellows (10), and vacuum pump, etc. (4) are made by inserting a vacuum sealing gasket between the vacuum flanges attached to each. This is done by tightening the bolts and nuts, which are not shown in the figure.
(This is shown in the enlarged view and will be described later.) Figure 1 shows an example where the vacuum container (1) is subjected to high-temperature baking or a high magnetic field is generated, and the bellows (■0) stretches the longest. FIG. 2 shows the state when the bellows (10) is retracted. If the bellows (10) is a welded bellows, it is easy to make the length when it is extended to its longest length more than 10 times the length when it is shortened to its shortest length, and depending on the product, it can be made to be 20 to 30 times the length when it is shortened to its shortest length. It is also possible. Bellows (10
) A vacuum flange (11) is attached to one end by welding or the like, and a vacuum flange (12) is attached to the other end.

An inner tube (13) is attached to the inner circumference of the vacuum flange (11) by welding or the like. The outer diameter of the inner tube (13) is smaller than the inner diameter of the bellows (10), and the length is the length when the bellows (10) is shortened to its shortest length (bellows (10)
) is approximately equal to the shortest length of ). Further, a groove for storing a gasket is provided near the inner circumference of the vacuum flange (12), and a vacuum sealing gasket (14) is installed therein. A through hole (15) is bored near the outer periphery of the vacuum flanges (11) and (12), and when holding the bellows (10) in the retracted position, the through bolt (16) is inserted into the through hole (
15) and tighten with the nut (17).

Figure 3 is an enlarged view of the bellows part in Figure 1, and Figure 4 is an enlarged view of the bellows part in Figure 2, showing the vacuum flange (18) attached to the connection port (2) and the bellows (10). The connection with the vacuum flange (11) is as follows.

Sandwich the vacuum sealing gasket (19) and tighten the bolt (
20) and the nut (21), and the vacuum flange (12) attached to the other end of the bellows (10) and the vacuum flange (22) attached to the vacuum pump, etc. (3).
The connection with the vacuum seal gasket (
23), and then tighten the bolt (24) and nut (25).
) to tighten.

The other components have already been explained in FIGS. 1 and 2.

Next, the operation of the first embodiment will be explained. Figures 1 and 3
The figure shows an example in which the vacuum container (1) performs high-temperature baking or generates a high magnetic field, and shows the state in which the bellows (10) is extended to its maximum length.In this way, the vacuum pump, etc. (4) Since it is installed at a location away from the vacuum container (1), it is out of the high temperature baking (or high magnetic field) range (5) of the vacuum container (1) and is not exposed to high temperatures or high magnetic fields. etc. (4) is no longer likely to be damaged. However, in this case, the first priority is to prevent damage to the vacuum pump, etc. (4), and the bellows (10) is used with it stretched out, so the amount of gas released from the bellows (10) must be reduced. On the other hand, as shown in Figures 2 and 4, the vacuum container (1) does not perform high-temperature baking. When a high magnetic field is not generated, the bellows (lO) can be shortened to the shortest possible length without breaking the vacuum, such as a vacuum pump, etc.
4) can be placed close to the vacuum vessel (1). In this case, at the free end of the inner tube (13) the bellows (1
The vacuum sealing gasket (14) installed in the gasket storage groove of the vacuum flange (12) of The gas released from the bellows (10) can be cut off by isolating it from the vacuum area (in the device), and only the amount of gas released from the inner surface of the inner tube (13) (the surface in contact with the vacuum area) must be considered. That's a good thing. By hammering, the amount of gas released can be the same as that of a normal tube of length, which in this case is approximately equal to the shortest length of the bellows (10). In addition, in order to firmly press the vacuum sealing gasket (14) against the free end of the inner tube (13) to achieve a vacuum seal, the vacuum flange (1
It is also possible to fix by passing a through bolt (16) between 1) and (12) and tightening it with a nut (17).

As described above, when the bellows (10) of Example 1 is used in a long stretched state, the free end of the inner tube (13) and the vacuum flange (12) of the bellows (lO) do not come into contact with each other. The bellows (10) can fully perform its function. (However, in this case, it is not possible to reduce the amount of gas released from the bellows (10).) Also, when the bellows (10) is shortened to its shortest length, the inner tube (
Vacuum flange (1) of the bellows (10) at the free end of (13)
Press the vacuum sealing gasket (14) installed on the inner tube (13) to vacuum seal the bellows (10).
), it is only necessary to consider the amount of gas released from the inner surface of the inner tube (13), i.e., the amount of gas released from a normal tube whose length is approximately equal to the shortest length of the bellows (10). The effect is that it can be reduced to the same value as .

Embodiment 2 FIG. 5 shows an embodiment in which the configuration of the vacuum seal part when the bellows (10) is contracted is changed, and the vacuum flange ( Press the vacuum sealing gasket (14) installed on 12) to vacuum seal. The rest is the same as in Example 1. In this case, there is an advantage that vacuum sealing is possible even if the central axis of the inner tube (13) and the central axes of the vacuum flange (12) and the vacuum sealing gasket (14) are slightly misaligned. It has the same effect.

Embodiment 3 FIG. 6 shows a vacuum flange (12) instead of using the vacuum sealing gasket (14) as the vacuum holding part in Embodiment 1.
) is provided with an inclined surface (27) on the inner periphery of the inner tube (13).
An inclined surface (28) is provided on the outer periphery of the free end of the bellows (
10), these inclined surfaces (27), (28
) are in contact with each other for vacuum sealing, but the rest is the same as in Example 1. In this case, since the metal surfaces are brought into contact for vacuum sealing, there is an advantage that the vacuum sealing gasket (14) of Embodiment 1 is not required.
It has the same effect.

1 The present invention provides that in the vacuum vessel of a nuclear fusion device or the vacuum duct of a ring-shaped accelerator, the electrical resistance of the bellows is lower than that of a normal tube when generating fusion plasma or rotating an accelerated beam. Because of their large size, bellows are often used to prevent eddy currents (also called induced currents or wall currents) flowing through the walls of vacuum vessels and vacuum ducts (bellows are interposed between ordinary pipes or thick-walled parts). In this case, if the bellows with inner tube of the present invention is used, the bellows can be contracted and heated when electrically heating the vacuum vessel wall or the vacuum duct wall for baking the vacuum vessel of a nuclear fusion device or the vacuum duct of an accelerator. By pressing the vacuum sealing gasket installed on the vacuum flange at the other end of the bellows with the free end of the inner tube, the amount of gas released from the bellows can be reduced as described above, and the current for electrical heating has a large electrical resistance. An additional effect is that the current flows through a circular tube with a lower electrical resistance than the bellows, so that no excessive current flows through the bellows, which eliminates the risk of burning out the bellows. (however,
In this case, should a metal gasket be used as the vacuum seal gasket?

Alternatively, it is necessary to use a vacuum seal with metal surface contact. [Effects of the Invention] As explained above, according to the vacuum device of the present invention, when the bellows is used in a long stretched state, Since the free end of the inner tube and the vacuum flange at the other end of the bellows are not in contact, the bellows can fully perform its function.

(However, in this case, the amount of gas released from the bellows cannot be reduced.) Also, when the bellows is shortened to its shortest length, the free end of the inner tube is installed on the vacuum flange at the other end of the bellows. Since the bellows can be isolated from the vacuum area within the inner tube (i.e., the vacuum area of the vacuum device) by pressing the vacuum retaining part, the amount of released gas can be reduced from the amount of gas released from the inner surface of the inner tube (i.e., the bellows). This has the effect of reducing the amount of gas emitted from a normal pipe whose length is approximately the same as the shortest length of the pipe.

In addition, when the vacuum device of the present invention is applied to a vacuum vessel of a nuclear fusion device or a vacuum duct of an accelerator, the bellows may be contracted when heating the vacuum vessel wall or the vacuum duct wall with electricity for baking. When the free end of the bellows is pressed against a vacuum sealing gasket (in this case a metal gasket) installed on the vacuum flange at the other end of the bellows, in addition to the above-mentioned effects, the heating current An additional effect is that the current flows through a circular tube with a lower electrical resistance than a large bellows, so that no excessive current flows through the bellows, eliminating the risk of burning out the bellows.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of the first embodiment of the vacuum device of the present invention when the bellows is extended, FIG. 2 is a vertical cross-sectional view of the bellows of FIG. 1 when it is retracted, and FIG. 4 is an enlarged view of the bellows part in FIG. 2, FIG. 5 is an enlarged view of main parts showing the second embodiment, and FIG. 6 is an enlarged view of main parts showing the third embodiment. 7 and 8 are vertical sectional views of the vacuum device invented as an example in the process of completing Embodiment 1, with the bellows extended and retracted, and 9.
1 and 10 are vertical cross-sectional views of a conventional vacuum device in which the positions of the vacuum pump and the like are changed. 1... Vacuum container, 4... Vacuum pump, etc. including vacuum gauge, etc., 5... Range of high temperature baking or high magnetic field.

Claims (2)

[Claims] (1) It is equipped with a vacuum container, a vacuum pump that evacuates the inside of the vacuum container, and a vacuum gauge that displays the degree of vacuum inside the vacuum container, and is capable of performing intermittently high-temperature baking or generating a high magnetic field. In a vacuum device used for other purposes, a vacuum pump, vacuum gauge, etc. are connected to a vacuum container via a bellows, and when the vacuum container is baked at a high temperature or a high magnetic field is generated, the bellows is extended to disconnect the vacuum pump, vacuum gauge, etc. from the vacuum container. A feature is that the bellows can be installed at a remote location, and the vacuum pump, vacuum gauge, etc. can be installed close to the vacuum container by contracting the bellows without breaking the vacuum when high-temperature baking is not performed or a high magnetic field is not generated. vacuum equipment. (2) An inner tube with a length approximately equal to the shortest length of the bellows is provided at one end of the bellows, and when the bellows is contracted, the free end of the inner tube is airtightly connected to a vacuum holding part installed at the other end of the bellows. 2. The vacuum device according to claim 1, wherein the bellows is abutted to form a vacuum seal, thereby isolating the bellows from a vacuum region within the inner tube.