JPH01237365A - Cryopump device - Google Patents

Abstract

PURPOSE:To heighten the cooling effect and improve the exhaust ability by providing cooling devices in the housing and cover of a cryopump, respectively, and opening the cover to nearly full admission in the position where a pump body can not be looked squarely from the beam dump of a vacuum vessel. CONSTITUTION:When the gas in a first pump body 51 is exhausted, the cover 15a of a first pump housing 12a is fully opened, and then a first sluice value 10a is fully closed to condense or adsorb the gas within a vacuum vessel 4 on a cryo face. When a second pump body 5b is regenerated simultaneously, the cover 15b of a second pump housing 12b is fully closed and then a second sluice valve 10b is fully opened to desorb the exhaust gas molecule from the cryo face. Then, each housing 12a, 12b and each cover 15a, 15b are cooled by each cooling tube 21, 23 provided therein, respectively. Each cover 15a, 15b is set up so that it is opened to nearly full admission in the position where each pump body 5a, 5b can not be looked squarely from a beam dump 18.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a cryopump device used in an ultra-high vacuum device, a nuclear fusion device, etc., and particularly relates to a cryopump device containing a cryopump body. The present invention relates to a cryopump device that is used when a storage box is placed inside a vacuum container that is an object to be evacuated, and there is a high-temperature object inside the vacuum container.

(Prior Art) In the present invention, what is originally called a "cryo pump" is referred to as a "cryo pump main body" to distinguish it from a cryopump storage box or a vacuum container.

In a cryopump, the cryopump main body is housed in a vacuum container, and exhaust gas molecules in the vacuum container are condensed onto the metal surface, that is, the cryo surface, which is cooled with a refrigerant such as liquid helium, or an adsorbent is used. This is a vacuum pump that lowers the pressure inside a vacuum container by collecting and accumulating exhaust gas molecules by adsorbing them, and there are various types such as cryo-condensing pumps, cryo-adsorption pumps, and cryo-trapping. FIG. 6 shows an example of a conventional conventional cryopump device. (2) is an object to be evacuated such as a nuclear fusion device, (2) is an exhaust pipe, (2) is a gate valve, and (2) is a vacuum container that houses the cryopump body (g). The cryopump main body (c) is composed of a cryopump (c), a cryopump (6), a siebron baffle (2), a radiation shield plate (8), etc.

The cryopump main body ■ is a vacuum pump that accumulates the exhaust gas on the cryo surface by condensing it (or adsorbing it), so when the operation of the object to be pumped (for example, a nuclear fusion device, etc.) is stopped, the cryo surface (6) It is necessary to raise the temperature to remove the accumulated exhaust gas from the cryo surface and exhaust it to the outside using another vacuum pump.

This is called "cryo pump regeneration," and in cryopumps, it is necessary to perform "exhaust" and "regeneration" alternately at certain fixed time intervals.

The vacuum container (a) has another exhaust pipe (9) and a gate valve (10).
An auxiliary vacuum pump (11) is attached via. This auxiliary vacuum pump (11) is generally a mechanical pump (e.g. turbo molecular pump, oil rotary pump, etc.), and when supplying refrigerant liquid to the cryopump main body ■, it is necessary to provide vacuum insulation. (a) Used to maintain a high vacuum inside the cryopump or to discharge exhaust gas released from the cryo surface (6) to the outside during cryopump regeneration. In addition, the gate valve (3) is fully opened when the cryopump body (2) evacuates the object (1) to be evacuated, and is fully closed when the cryopump body 0 is regenerated. On the other hand, the gate valve (10)
closes when the cryopump main body 0 is evacuated and opens during regeneration.

In this conventional cryopump body 0, there is a vacuum vessel in which the cryopump body ■ is housed and an object to be evacuated (
g) is connected via the exhaust pipe ■ and the gate valve (3), and is limited by the conductance of the exhaust pipe ■ and the gate valve (3), making it impossible to obtain a large exhaust speed. There was a drawback. Therefore, it is conceivable to install the cryopump main body (c) directly inside the object to be evacuated 1, but in this case, there arises the disadvantage that the object to be evacuated cannot be continuously pumped for a long period of time. This is because the cryopump body (c) cannot be regenerated if the pumping object (i) is continuously pumped for a long period of time.

That is, if the cryopump is not regenerated for a long period of time, exhaust gas molecules will accumulate too much on the cryopump (6), and the pumping capacity of the cryopump will decrease, eventually reaching zero.

Therefore, as shown in Figures 7 to 9, the cryopump main body ■ (add suffixes a and b to distinguish it from 1st and 2nd) is placed in the cryopump storage box (12). A plurality of cryopump storage boxes (12) are installed in a vacuum container (which is the object to be evacuated), and each cryopump (13) is alternately operated for evacuation and regeneration to achieve high pumping speed and long-term operation. A cryopump device that enables continuous pumping operation has been published in the following literature. (KfK 3680.
FPA-83-7, IJWFDM-600: TASKA
-M Report, A Low Co5t, Ne
ar Team TandemMirror Devi
ce for Fusion Technology
Testing.

P349~P356 (P7.3-1~P7.3-8)
, Kernforschungszentrum
Karlsruhe (KfK), (April 19
84):] These multiple cryopump storage boxes (12
) (When distinguishing from 1st and 2nd, add subscript asb)
The lids (first and second
When distinguishing from
) can open and close the lid (15). Cryopump storage box (12) and lid (15)
are provided with a sealing surface (12S) and (15S), respectively, and when the lid (15) is closed, the sealing surface (12S) is provided between the lid (15) and the cryopump storage box (12).
) and (155) are in contact to form a complete vacuum seal. The first and second cryopump bodies (5a
L (5b) is the cryopump body described in Figure 6■
It has the same function as . (16) is an exhaust pipe attached to the cryopump storage box (12). This first. The second cryopump main body (5a), (5b) and the first cryopump main body (5a), (5b). Second cryopump storage box (12a), (
12b) and 1st. Second lid (15a), (15b
) etc. - As an example, the 9th cryopump (13)
As shown in the figure, it is installed directly into a vacuum container (4) that is the object to be evacuated. In FIG. 9, when exhausting with the first cryopump main body (5a), the first cryopump storage box (12a) and its lid (15a) are fully opened, and the first cryopump storage box (12a) and its lid (15a) are fully opened, and the The first gate valve (1
0a) is fully opened, the gas in the vacuum container) is collected and accumulated on the cryo surface, and then evacuated. In this way, since there is no exhaust pipe or gate valve interposed between the vacuum container (a) and the first cryopump body (5a) as described in FIG. 6, there are no restrictions due to their conductance. The first cryopump body (5a) can have a large pumping speed. At the same time, the second cryopump body (
5b), the lid (15b) of the second cryopump storage box (12b) is fully opened, and the exhaust pipe (16
) After fully opening the second gate valve (10b) installed in the middle of Exhaust gas molecules are separated from the cryo surface and exhausted to the outside by an auxiliary vacuum pump (11). At this time,
Second cryopump storage box (12b) and lid (15b)
Since both seal surfaces (125) and (15S) are in contact with each other and are completely vacuum sealed, the exhaust gas released from the cryo surface will not mix into the vacuum container (a). After a certain period of time has elapsed, the lid (15a) of the first cryopump storage box (12a) is fully opened, the first gate valve (10a) is fully opened, and the first cryopump main body is opened. At the same time, the lid (15b) of the second cryopump storage box (12b) is fully opened, the second gate valve (10b) is fully opened, and the second cryopump storage box (12b) is fully opened.
Evacuation is continued by the cryopump main body (5b). In this way, this cryopump device has a large pumping speed and is capable of continuous pumping by repeating pumping and regeneration alternately between the first and second cryopump bodies (5a) and (5b). It has advantages.

In addition, plasma (or beam) (1
7) and the beam dump that receives the plasma (17) (Here, the high-temperature objects in the vacuum container such as the beam dump, direct converter, and first wall of nuclear fusion that receive the plasma and beam are collectively referred to as "beam dump". ) (18
), the beam dump (18) is a plasma (1
7), the beam dump (1
8) and cryopump storage box (12a), (12b)
A water cooling plate (19) is installed between the beam dumps (18).
) so that the cryopump bodies (5a) and (5b) cannot be seen directly, and the radiant heat from the beam dump (18) is removed by a water cooling plate (19).

(Problem to be Solved by the Invention) However, in this conventional cryopump device, the first lid (
15a) was always open at right angles as shown in FIG. The reason for this is that the lid (15a) opens less often.
This is because it is thought that the conductance of the opening between the cryopump storage box (15a) and the cryopump storage box (12a) becomes small, and a restriction due to the conductance occurs, making it impossible to obtain a high pumping speed.

For this reason, a space (at least a space as wide as the lid (15a)) is required in the vacuum container (a) to keep the lid (15a) fully open. In addition, plasma (
or a beam of ions, electrons, neutral particles, etc.) (17) and a beam dump (18) that receives the plasma (17), in order to remove the radiant heat from the beam dump (18), Dump (18) and each cryopump storage box (12a), (12b) lid (15a),
It is necessary to install a water cooling plate (19) between (15b). It is also necessary to prevent the water-cooled plate (19) from coming into contact with the plasma (17) as much as possible. That is, the water cooling plate (1
If 9) continues to be in contact with the plasma (17), the water cooling plate (19) may be damaged, the plasma (17) may be cooled, or evaporation or sputtering may occur from the water cooling plate (19) during the plasma (17). This is because there is a high possibility that metal atoms etc. released by the above may become impurities and be mixed in.

Therefore, for this reason, the lid (
15a) to keep it fully open (at least the lid (
15a)), in addition to the space for installing the water cooling plate (19) (at least the installation width L of the water cooling plate (19)
This has the drawback that the vacuum container (a) also becomes large. Furthermore, if the cryopump main body (5a) is made to be visible directly from the beam dump (18) without installing the water cooling plate (19), the cryopump main body (5a) is
5a) Chevron baffle ■ and radiation shield plate (8)
A coolant that cools the cryo surface (usually liquid nitrogen, etc.) or a coolant that cools the cryo surface 0 (usually liquid helium, etc.)
The consumption of will rapidly increase and become a huge amount. Furthermore, liquid helium and liquid nitrogen are uneconomical because they are more expensive than water, which is a normal cooling fluid. Additionally, if the chevron baffle (■), the radiation shield plate (8), and the cryo surface 0 are heated by the radiant heat from the beam dump (18) and cannot be cooled sufficiently, the exhaust capacity will decrease, and in some cases become zero, and the cryo surface will The pump (13) will no longer be able to maintain normal exhaust capacity. Also, the lids (15a) of the cryopump storage boxes (12a) and (12b).

(15b), even if the cryopump bodies (5a), (5b) cannot be seen directly from the beam dump (18), the radiant heat from the beam dump (18) will cause the cryopump storage boxes (12a), (12b) and lid (1
5a) and (15b) are heated and the temperature rises, resulting in the same situation as above.

The purpose of the present invention is to avoid increasing the consumption of the cooling liquid that cools the chevron baffle and radiation shield plate of the cryopump body and the cooling liquid that cools the cryo surface when there is a beam dump in the vacuum vessel. Another object of the present invention is to provide a cryopump device that can maintain normal pumping performance.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a cryopump body, a cryopump storage box for storing the cryopump body, and a method for sealing and opening the cryopump storage box. A plurality of cryopumps consisting of a lid are arranged in a vacuum container having a beam dump inside, a cooling device is attached to the cryopump storage box and the lid, and when the lid is opened, the cryopump is removed from the beam dump. Arrange the lid so that it cannot be viewed directly.

(Function) By doing this, when the lid is opened and the cryopump is evacuating, you can make sure that the cryopump storage box and lid are being cooled by the cooling tube, and that the lid is placed in a position where the cryopump body cannot be seen directly from the beam dump. Because the radiant heat from the beam dump does not reach the cryopump body, the cryopump equipment can maintain normal pumping capacity without increasing the consumption of the coolant that cools the cryopump body. is obtained. Further, since the conventional water cooling plate (19) shown in FIG. 9 is no longer necessary, miniaturization becomes possible.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3. In these drawings, elements and parts that have the same functions as those in FIGS. 6 to 9 are given the same reference numerals, and some explanations are omitted.

Also, the first one with the same name. If not distinguished from the second, subscript a,
b etc. are omitted. (12) is a cryopump storage box that houses the cryopump main body (■), and (12S) is its sealing surface. A cooling surface (21) is attached to the outer surface of the cryopump storage box (12), through which a cooling fluid (usually water) can flow to cool the cryopump storage box (12). Also, cryopump storage box (12)
A lid (15) is attached via a drive shaft (14) attached to the. (15S) is the sealing surface of the lid (15). A cooling pipe (23) is attached to the outer surface of the lid (15), through which a cooling fluid flows to cool the lid (15). The lid (15) is a drive device (not shown)
can be opened and closed by rotating the drive shaft (14). A flexible tube (or bellows tube) (24) is connected to the end of the cooling tube (23) so that it does not interfere with the opening and closing operations of the lid (15). Lid (1
5) When the lid (15) and the cryopump storage box (12) are closed, the sealing surfaces (12S) and (15S) are in contact with each other to ensure a complete seal. A cryopump consisting of a cryopump body (c), a cryopump storage box (12), a lid (15), etc. is installed in a vacuum container (a) that is an object to be evacuated.

Next, the operation of this embodiment will be explained.

When exhausting with the first cryopump main body (5a),
Lid (15a) of first cryopump storage box (12a)
is fully opened (at an angle of approximately 60°, the conductance is approximately the same as at a right angle), the first gate valve (10a) is fully opened, and the gas in the vacuum container (a) is condensed on the cryo surface ( or adsorption) exhaust. At the same time, in order to regenerate the second cryopump main body (5b), fully close the lid (15b) of the second cryopump storage box (12b), fully open the second gate valve (10b), and then , the temperature of the cryo surface of the second cryopump body (5b) is raised, the exhaust gas molecules accumulated on the cryo surface are released from the cryo surface, and are discharged to the outside by the auxiliary vacuum pump (11). As before, after a certain period of time,
1st. The second lid (15a), (15b) and the gate valve (1
By reversing the opening and closing positions of (la) and (10b), the first cryopump body (5a) is regenerated, and the second cryopump body (5a) is regenerated.
Evacuation is continued by the cryopump main body (5b). In this way, the first and second cryopump bodies (5a)
By alternately repeating exhaust and regeneration between (5b) and (5b), continuous exhaust can be achieved. In the cryopump apparatus of this embodiment, the cryopump storage box (12a), (12b)
Since the lids (15a) and (15b) can be cooled by the cooling fluid flowing through the cooling pipes (21) to (23) as described above, the conventional water cooling plate (19) shown in FIG. The vacuum container (a) can be made smaller by the installation space (Lc) of the plate (19). Also, when opening the lid (15a) when exhausting the cryopump main body (5a), the cryopump main body (5a) should be in a position where it cannot be seen directly from the beam dump (18), and at a position as close to fully open as possible. This is because, as shown in Figure 1, by opening at an angle of about 60°, you can obtain conductance close to fully open even if you do not open to the right angle.For this reason, from the beam dump (18) The radiant heat does not enter the cryopump main body (5a), but the cryopump storage boxes (12a), (12b) and the lid (15a) receive radiant heat.
(15b) are the cooling pipes (21) and (2
3) The temperature does not rise because it is cooled by the cooling fluid flowing inside. For this reason, the cooling liquid (liquid nitrogen, etc.) that cools the chevron baffle ■ of the cryopump body (c) and the radiation shield plate (8), and the cooling liquid (liquid helium, etc.) that cools the cryo surface ■ are consumed. It is possible to maintain normal exhaust capacity as a cryopump (13) without increasing the volume. In Fig. 1, the end of the cooling pipe (21) and the end of the flexible pipe (24) connected to the cooling pipe (z3) penetrate the vacuum container (a) (not shown), and the cooling Pipe (21
), (23) The cooling fluid flowing inside the vacuum container (a) flows from outside the cryopump storage box (12a),
(12b) and the lid (15aL) to remove heat and then flow out of the vacuum container (a).

Next, another embodiment will be described with reference to FIGS. 4 and 5.

FIGS. 4 and 5 show a case where the cryopump storage box (12) has four lids (15).

In this case as well, a cooling pipe (21) is attached to the outer surface of the cryopump storage box (12), a cooling pipe (23) is also attached to the outer surface of the lid (15), and the cryopump storage box (12) is also provided with a cooling pipe (23).
12) and the lid (15) can be cooled by the cooling fluid flowing through the cooling pipes (21) and (23), so the water cooling plate (19) shown in FIG. 9 is not required. Furthermore, since the size of the lid (15) is 174 mm compared to the cryopump apparatus shown in FIGS. 1 to 3, the vacuum container (A) can be made even smaller. Other functions, effects, etc. of Structure 2 are the same as those of the embodiment shown in FIGS. 1 to 3 described above.

The cooling structure of the cryopump storage box and lid is not necessarily limited to a structure with a cooling pipe attached, but may also be a cooling device such as a so-called "jacket structure" in which two plates are pasted together and cooling fluid flows inside. Well, also the cooling fluid need not be limited to water only.

〔Effect of the invention〕

As explained above, the present invention provides a cryopump device in which a cooling device is attached to the outer surface of the cryopump storage box and the lid, and cooling fluid is allowed to flow inside the cooling device to cool the cryopump storage box and the lid. Therefore, when these cryopumps are installed in a vacuum vessel, a water cooling plate is not required, and the vacuum vessel can be made smaller by the space required for installing the water cooling plate. Furthermore, even when the lid is opened when exhausting the cryopump, the lid is placed in such a way that the cryopump body cannot be seen directly from the beam dump, so radiant heat from the beam dump does not enter the cryopump body. First, the temperature of the cryopump storage box and lid, which receive radiant heat, does not rise because they are cooled by the cooling fluid flowing through the cooling device attached to them. For this reason, the cryopump system can be used without increasing the consumption of the cooling fluid (liquid nitrogen, etc.) that cools the chevron baffle and radiation shield plate of the cryopump body, or the cooling fluid (liquid helium, etc.) that cools the cryo surface. It has the excellent effect of maintaining normal exhaust capacity.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the cryopump device of the present invention, FIG. 2 is a perspective view showing the external appearance of the cryopump in FIG. 1, and FIG. 3 is taken along the line ■-■ in FIG. 4 is a vertical sectional view showing another embodiment of the cryopump device of the present invention, FIG. 5 is a sectional view showing the cryopump of FIG. 4, and FIG. 6 is a conventional cryopump. 7 is a perspective view showing a conventional cryopump different from that shown in FIG. 6, FIG. 8 is a cross-sectional view along the line ■-■ in FIG. FIG. 8 is a longitudinal sectional view showing a cryopump apparatus in which the cryopump of FIG. 7 is installed in a vacuum container. 4. Vacuum container 5.5a, 5b. Cryopump body 12, 12a, 12b Cryopump storage box 13
... Cryopumps 15, 15a, 15b - Lid 18 ... Beam dumps 21, 23 - Cooling pipes that are cooling devices Representative Patent attorney Inoue - Male Figure 7

Claims (1)

[Claims] A plurality of cryopumps each consisting of a cryopump main body, a cryopump storage box for storing the cryopump main body, and a lid for sealing and opening the cryopump storage box are arranged in a vacuum container having a beam dump inside. A cryopump device, characterized in that a cooling device is attached to the cryopump storage box and the lid, and the lid is arranged so that when the lid is opened, the cryopump body is moved to a position where the cryopump main body cannot be directly viewed from the beam dump. .