JPS6069270A - Evacuating device - Google Patents

Abstract

PURPOSE:To reduce the heat load of gas to be discharged at the fore stage of a low temperature pump and improve the evacuating performance of the low temperature pump by a method wherein the gas, arriving at the entrance of the low temperature pump, is reflected against the inner wall of a bent path equipped with a cooling section at least one time. CONSTITUTION:A pair of low temperature pumps 12, 12 are connected to a duct 11 of evacuating side through an evacuating duct 13 as a bent path. The substantially T-shaped entrance of the duct 13 is formed as a cooling pipe 14 and gas is cooled to the degree of a room temperature by flowing the gas or liquid of refrigerant through a jacket, for example, equipped at the entrance. The gas, passing through the end of entrance of the cooling pipe 14, is reflected in the cooling pipe 14 at least one time even though the gas passes the outermost side of the pipe. Accordingly, the heat load, recieved by the low temperature pump 12, may be reduced remarkably.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a vacuum evacuation device attached to, for example, a nuclear fusion device, a large vacuum container for high-energy research, etc. This invention relates to a vacuum evacuation device that enables

[Background of the invention]

As is well known, vacuum evacuation equipment for nuclear fusion devices and large vacuum vessels for high-energy research uses the system to be evacuated.
A cryopump is used because a large capacity evacuation function is required and the gas to be exhausted contains radiant heat, high-energy shafts, radiation, etc.

Specifically, as shown in FIG. 1, for example, a cryopump 3 is connected to a duct 1 on the exhaust side via a gate pulp 2. However, with this configuration in which the cryopump 3 is installed on the axis of the duct 1 on the evacuated side, radiant heat, high-energy particles, radiation, etc. from the evacuated side are directly transmitted to the cryopump without attenuation. 3
As a result, the heat load on the cryopump 3 increases rapidly, and in some cases, the pump may become inoperable.

On the other hand, as shown in FIG. 2, for example, a T-shaped air inlet duct 4 is interposed between the evacuated side duct 1 and the cryopump 3, and the exhaust gas introduction passage to the cryopump 3 is bent. There is something. In addition, by opening and closing the gate pulp 2 provided in the inlet duct 4, one of the two cryopumps 3 is used for exhaust operation and the other is used for pump regeneration. That is, a turbo molecular pump 8 is connected to each cryopump 3 via a pulp 5, a regeneration exhaust duct 6, and a gate pulp 7. This turbo-molecular pump 8 allows one of the cryopumps 3 not used for exhaust operation to be regenerated with the gate pulp 2 attached thereto closed. In addition,
This turbo-molecular pump 8 is also used for preliminary evacuation before the evacuation operation by the cryopump 3. In this case, the valve 5 and duct 6 will be used for preliminary exhaust.

In the case of the configuration shown in FIG. 2, direct radiant heat from the exhausted side to the cryopump 3 can be avoided by reflecting the exhaust flow through the bent portion of the inlet duct 4. It becomes like this. However, in this popular hole duct 4, high-energy particles and radiation pass through the cryopump 3 after being reflected several times on the inner wall, so this popular hole duct 4 is subjected to a heating effect, and the cryopump 3 is heated. Since it is heated by conduction, a problem arises in that the exhaust performance deteriorates. On the other hand, in the case of radiation, it tends to attenuate depending on the number of reflections and the reflectance, but if the cryopump 3 is placed relatively close to the duct 1 on the exhaust side as shown in FIG. 2, the number of reflections will be reduced. The part leading to the cryopump 3 is also recessed, so the exhaust side duct 1
There is also a problem in that the cryopump 3 generates heat due to the radiation that directly enters the cryopump 3 from the cryopump 3, reducing the pumping performance.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and has a relatively simple configuration that allows the heat load of the gas to be discharged to be reduced at the front stage of the cryogenic pump, thereby maintaining the pumping performance of the cryogenic pump. The purpose is to provide a vacuum evacuation device that can.

[Summary of the invention]

In the vacuum evacuation device according to the present invention, a gas containing a heat load is evacuated from a system to be evacuated to a high vacuum state by a low temperature pump connected to the system to be evacuated via a bent passage. In the exhaust device, a cooling section is provided in the bent passage leading to the cryogenic pump, and the bending passage with the cooling part is set to a degree of curvature such that gas reaching the inlet of the cryogenic pump is reflected at least once on an inner wall of the passage. There is.

Preferably, the bent passage is a branch passage that is approximately T-shaped with respect to the evacuated system, and the cryopump is connected to the tip side of the branch passage via a gate pulp that can be selectively opened and closed. . As a result, a continuous large-capacity evacuation function can be obtained by switching the cryopump.

Further, the branch passage has a preliminary exhaust passage in a straight line with the system to be pumped, and a turbo molecular pump for preliminary exhaust is disposed on this preliminary exhaust passage. Thereby, rough evacuation can be performed quickly before using the low temperature pump.

In other words, unnecessary conductance on the piping can be avoided.

Furthermore, preferably, the turbo-molecular pump is connected to the passage upstream of the cryopump via a gate pulp through a regeneration conduit, and the turbo-molecular pump has a cryopump regeneration function. This allows the turbomolecular pump to be used for preliminary evacuation and cryopump regeneration, making it versatile.
Moreover, the exhaust action can be performed efficiently.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

A pair of cryopumps 12 are connected to a duct of an evacuated system such as a nuclear fusion device or a large vacuum vessel for high-energy research (not shown), that is, an evacuated side duct 11 via an exhaust hole duct 13 serving as a bent passage. There is. The exhaust hole duct 13 is first formed into a branch passage forming an approximately T-shape with respect to the exhaust system at the tip of the exhaust-side duct 11, and each tip of each branch passage is further bent into an approximately L-shape. The overall shape is approximately U-shaped. Exhaust hole duct 1
The approximately T-shaped inlet portion 3 is used as a cooling pipe 14. The cooling pipe 14 has a jacket structure, for example, and is cooled to about room temperature by flowing gas or liquid as a refrigerant.

The dimensional relationship of this cooling pipe 140 is D+-Ih b=- It is set to .

That is, according to this dimensional relationship, the cooling pipe 14 in FIG.
Even the outermost portion of the gas passing through the exit side end of the cooling pipe 14 will be reflected within the cooling pipe 14 at least once, as shown by the dashed line A in the figure.

Note that a Niketo hull 7'' 15B, 15C is provided between the cooling pipe 14 and the cryo-def 1120.

Further, a duct 16 as a preliminary exhaust passage is provided in the center of the cooling pipe 14, that is, on the coaxial opposite side of the duct 11 to be exhausted. 17 are arranged. This turbo molecular pump 17 has gate pulps 15E and 15F in the upstream passage of the cryopump 2 (this part is referred to as the cryopump manifold 18).
Roughing manifold 19 as a regeneration conduit via
connected by.

Note that 20 is a pedestal for supporting the pipe line, and 21 is a preliminary pipe from the exhaust hole duct 13.

The exhaust action is performed as follows.

That is, during preliminary exhaust, the gate valve 15B.

15C, 15E, and 15F are closed, gate pulp 15D is opened, and turbo molecular pump 17 is operated.

Since the duct 16 is provided coaxially with the exhaust side duct 11, unnecessary contactance on the piping for performing this preliminary exhaust can be avoided.

Further, during main exhaust, the gate pulp 15D for preliminary exhaust is closed, and one of the gate pulps 15B and 15C of the exhaust hole duct 13 is closed. Then, the cryopump 12 on the gate valve opening side is operated, and the cryopump regeneration gate valve 15E of the cryopump manifold 18 is activated.

15F opens the closed side of the gate pulps 15B and 15C, closes the open side, and operates the turbo molecular pump 17 to simultaneously reactivate the cryopump 12 on the unused side. By alternately operating the two cryopumps 12, continuous evacuation is performed, and the unused cryopump 12 additionally performs a regeneration action (9).

According to the vacuum evacuation apparatus according to this embodiment having such a configuration, the high temperature radiant heat from the side to be exhausted is absorbed by the cooled exhaust hole duct 13 and the gate pulp 15D facing the side duct 11 to be exhausted. , each cryopump 12
The conduction heat to is significantly reduced. Furthermore, as described in the above configuration, since all the gas collides with the inner wall of the cooling pipe 14, the radiation reaches the cryopump 12 (depending on the material used and the number of reflections), and the energy is attenuated to the room temperature level. Therefore, the thermal load applied to the cryopump 12 is significantly reduced. Furthermore, since the cooling pipe 14 is provided, the cryopump 12 may be placed outside, increasing the size of the device. By arranging the ion pump 12, the regeneration time of the Schiff 2 ion bomb 12 can be shortened and the configuration can be made relatively compact. In addition, cryopump 12
It goes without saying that the installation of the cooling pipe 14 prevents the heating of the pipes from increasing in temperature (10) due to electric heating.

In the above embodiment, a configuration using a pair of cryopumps 12 has been described, but it goes without saying that the number of cryopumps and the piping configuration can be variously modified other than those shown in the above embodiment.

〔Effect of the invention〕

As described above, according to the present invention, a cooling section is provided in the curved passage leading from the evacuated system to the cryogenic pump, and the bent passage with the cooling section supplies gas to the cryogenic pump inlet at least once to the inner wall of the passage. By setting the degree of curvature that can be reflected by the pump, it is possible to shield and reduce the heat load due to high-temperature heat radiation from the pumped side, and the nuclear calorific value due to high-energy particles or radiation. A predetermined exhaust capacity can be maintained for a long period of time without the exhaust performance being inhibited by heat load.

[Brief explanation of the drawing]

FIGS. 1 and 2 are plan views showing different conventional examples, and FIGS. 3 and 4 show an embodiment of the present invention (11). FIG. 3 is a plan view, and FIG. is a side view. 11... Exhaust side duct, 12... Cryopump (low temperature pump), 13... Exhaust hole duct (bent passage)
, 14-... cooling pipe (cooling section), 15B, 15C. 15D, 15E, 15F...gate valve, 16...
・Preliminary exhaust passage (duct), 17 river turbo molecular pump. Agent Patent Attorney Tatsuyuki Unuma (12) 1st Ward Dormitory 2 Third Power

Claims (1)

[Claims] 1. Vacuum evacuation in which gas containing a heat load is evacuated from a system to be evacuated to a high vacuum state by a low-temperature pump connected to the system to be evacuated via a bent passage. In the device,
A cooling section is provided in the curved passage leading to the low temperature pump, and the curved passage with the cooling section has a degree of curvature that allows the gas reaching the inlet of the low temperature pump to be reflected at least once on the inner wall of the passage. Features vacuum exhaust equipment. 2. The bent passage is a branch passage that has a substantially T-shape with respect to the pumped system, and the cryopump is a cryopump connected to the tip side of the branch passage via a gate pulp that can be selectively opened and closed. A vacuum evacuation device according to claim 1, characterized in that: 3. The branch passage has a preliminary exhaust passage in a straight line with the system to be exhausted, and a turbo molecular pump for preliminary exhaust is disposed on the preliminary exhaust passage. The vacuum evacuation device according to item 2. 4. The turbo-molecular pump is connected to the passage on the upstream side of the cryopump via a gate pulp through a regeneration conduit, and the turbo-molecular pump has a cryopump regeneration function, as set forth in claim 3. vacuum evacuation equipment.