JPS58131382A - Cryosorption pump - Google Patents

Abstract

PURPOSE:To enable to form a condensed layer of adsorptive gas uniformly only on a cryogenic surface and make it unnecessary to complicate the whole part of the titled pump when enlarging the area of the cryogenic surface, by adding a simple element. CONSTITUTION:Adsorptive gas introduced from the exterior is momentarily condensed on the first cryogenic surface 25, then evaporated, and the absorptive gas thus evaporated is condensed on the second cryogenic surface 24 to form the condensed layer of the adsorptive gas. Thus, it is possible to set only the first cryogenic surface 25 at an extremely low temperature, the whole quantity of the adsorptive gas introduced can be condensed on the first cryogenic surface 25 without causing any condensation on parts around an introducing port for the gas, and the gas condensed on the first cryogenic surface 25 is transferred onto the second cryogenic surface 24 to form the condensed layer of the adsorptive gas, so that the condensed layer can be formed in a uniform thickness even when the surface area of the second cryogenic surface 24 is large. Accordingly, it is unnecessary to divide the introducing port for the gas even in the case of a high-capacity cryosorption pump, and simplification of the pump or the like can be contrived.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to the modification of cryosorption pumps. Cryosorption pumps are used.0 Cryosorption pumps usually use a cryogenic surface (cooled with liquid helium) in the atmosphere to be evacuated.
Approximately 4.2 K) is provided, and the above cryogenic surface is
By forming an adsorbent gas condensation layer such as @NHHr Cot s flF@, and allowing gas molecules in the atmosphere to adhere to the adsorption gas condensation layer, even helium, hydrogen, etc. that cannot be exhausted with a general or lyosoap pump can be evacuated. In order to prevent heat from penetrating into the cryogenic surface due to radiation etc., such cryosorption pumps are usually configured to prevent heat from entering the cryogenic surface by radiation, etc. Surrounded by a shield body, the heat shield body is cooled with liquid nitrogen, etc., and its surface [low temperature (approx.
) [Problems in the Background Art] In the conventional cryosorb cylinder pump configured as described above, the cryo-temperature surface is surrounded by a heat shield, so that the cryo-sorbing cylinder is kept at a temperature of 0 by radiation. It has the advantage of being able to suppress the amount of heat that penetrates into the surface, but on the other hand, when adsorbent gas is introduced, this adsorbent gas tends to condense and adhere to the surface of the heat shield, and therefore It is not possible to form an adsorbent gas condensation layer of a certain thickness, and as a result, there is a problem in that the performance as a pump is relatively low. In addition,
When the heated body is removed, the introduced adsorptive gas tends to condense and adhere to the vicinity of the gas inlet of the vacuum container.To solve this problem, it is necessary to remove the adsorbent gas near the gas inlet The temperature must be maintained above the boiling point, resulting in
Heat intrusion into the cryogenic surface due to radiation increases. Secondly, in order to maintain the cryogenic surface at a cryogenic temperature (approximately 4.2°K), a large amount of refrigerant is required, resulting in an increase in operating costs. Furthermore, if the exhaust space is large,
It is also necessary to increase the area of the cryogenic surface, but in this case, in order to form a uniform adsorptive gas condensation layer on the cryogenic surface, in conventional pumps the gas inlet is divided into multiple parts. I am trying to set it up. As a result, the equipment became multi-tracked and had a large lid, increasing manufacturing costs. The aim is to form a condensed layer of adsorbent gas uniformly only on the cryogenic surface by adding a simple element, and to reduce the area of the cryogenic surface by increasing the area. A cryo-soap silane pump that does not have the risk of the entire length becoming 1 m, thereby improving the performance of the pump and reducing manufacturing and operating costs. The cryosorb silane pump is evacuated 111! First and second cryogenic surfaces whose temperature can be controlled from outside the atmosphere are provided in the atmosphere, and when forming an adsorbent gas condensation layer, a condensation layer of adsorbed gas is first formed on the first cryogenic surface. Then, the adsorptive gas condensed and adhered to the first cryogenic surface is evaporated, and the vaporized adsorptive gas is condensed and adhered to the second cryogenic surface. It is characterized by the formation of an adsorbent gas condensation layer.

〔Effect of the invention〕

In this way, the adsorptive gas introduced from the outside [once Ip
After condensing and adhering to the cryogenic surface of No. 11, this [evaporates]
By condensing and adhering this evaporated adsorbent gas 1 to the cryogenic surface of the adsorbent gas 1, an adsorptive gas condensation layer is formed on the cryogenic surface of the absolute 2, so when the adsorbent gas is introduced, Isl Only the cryogenic surface of [1] can be kept at an extremely low temperature compared to other surfaces, and as a result, adsorbent gas does not condense and adhere near the gas inlet, and the total amount of adsorbent gas introduced [1st Can be deposited by condensation on cryogenic surfaces.

The adsorptive gas condensed and adhered to the first cryogenic surface [is transferred to the second cryogenic surface and an adsorptive gas condensation layer is formed on the 20th cryogenic surface, so even if Even if the surface area of the low-temperature surface is large, an adsorbent gas condensation layer of uniform thickness can be formed on the low-temperature surface of the 20th volume. Therefore, even if the gas inlet is for a large capacity, there is no need to separate it, which simplifies the device.

It can be made smaller and lighter, and manufacturing costs can be reduced.

In addition, the position of the adsorptive gas inlet and the position of the cryogenic surface of Ill, #E2 [by selecting
Since the O1 low O surface can serve as a heat shield for the cryogenic surface of JI2, it is possible to prevent heat from entering the cryogenic surface of M2C1 due to radiation from the gas inlet side. , the cold rigor required to cool the cryogenic surface of JII2 mentioned above can be saved.

[Embodiments of the invention]

Embodiment of the present invention This will be explained with reference to the X plane. FIG. 2 is a sectional view of a cryo-to-plane pump according to an embodiment of the present invention.

In the figure, reference numeral 1 is a chamber whose interior is to be evacuated, and a hole 2 is provided in a part of the wall of this portion I11. and,
A cryo-two-plate bomb L is installed through the hole 2.

The cryo-two pre-1 pump L is roughly divided into a hazardous container 4 which is airtightly connected to the hole 2, a gas supply system 5 which selectively supplies adsorbent gas into the container 4, and a gas supply system 5 which selectively supplies adsorbent gas into the container 4.
It consists of an exhaust section C provided inside the container 4, and a temperature control section 7 that selectively controls the temperature of this exhaust section 6 from outside the container 4.

The container 4 has a cylindrical body 13 provided in the wall of the room 1 on one end side and has an opening JJI having the same diameter as the hole 2 and #1, and has a small diameter opening JJJ on the other end side. , and a plate 14 provided to airtightly close the opening 12' of the cylindrical body 13. Opening 11 of the cylindrical body 13
A flange portion 15 projecting outward is integrally formed on the outer edge of the 7-rank portion 15 when the hole 2 and the opening 11 are aligned with the t-axis by the bolt 1-. The clamp is fixed to the wall of the room 1, thereby airtightly connecting the cylindrical body 13 and the portion W11. Next, a flange portion 1r that projects outward is also formed on the outer edge of the opening 12 of the cylindrical body 13, and this flange portion 11
The plate body 14 is hermetically secured to the plate body 14 by bolts 18.

Therefore, in the central part of the plate 14, this plate JJI
A pipe 19 is provided to pass through the container in an airtight manner, and the end of this pipe 19t located outside the container is connected to the gas supply system 5. The gas supply system 5 is Ar j N) 13
# COx + S Fa O adsorbent scum consists of a cylinder 2o containing the gas and a pulp 21 which selectively guides the gas in the cylinder 20 into the container 4 via the pipe 19.

The exhaust section I is constructed as follows.

That is, an opening 1 is formed in the cylindrical body 13 constituting the container 41r.
The chevron-shaped cooling bodies 22 and 23 are arranged in four stages from the first side to the opening 12 side. The cooling bodies 22, 23, 24, 25 are constructed in the same way, and are cooled by the refrigerant flowing through the pipes 26.2jl, 28.29.

2g of pipes to cool each cooling body 22.23, 24.25
.

The temperature control unit 1 is mainly composed of, for example, a refrigerant source and a pulp that controls the flow rate of refrigerant from the refrigerant source. Specifically, the liquid nitrogen cylinder 3 is passed through the pipe 26f that cools the cooling body 225f and the pulp 30.
Pipe 2af is connected to the liquid helium cylinder 33 through the cooling body j41jH and is connected to the liquid helium cylinder 35 through the pulp 34, and is connected to the liquid helium cylinder 35 for cooling through the cooling body 25f. It is connected to a liquid helium cylinder sr via a pipe, g9t-pulp 36. In the figure, reference numeral 38 indicates the reflecting plate 1.Next, an example of use of the Thaliosoap pump configured as above will be described.

First, use the omniscient vacuum pump to raise the vacuum level in the room to a certain level. Next, open 1 set of balloons and cool body 2.
5 [Liquid helium [is passed through the pipe 29 to be cooled and the cooling body zs11 (cooled). ' * "m * CO, #
8 Set to be a cryogenic surface below the condensation temperature of adsorbent gas such as Fa. Next, the pulp 21kHz is released and adsorbent gas is introduced into the container 4 from the pump 20.

The introduced adsorptive gas condenses and adheres to the cryogenic surface of the cooling body 25 until the adsorptive gas condensation layer on the surface of the cooling body 250 becomes sufficiently thick, and then the pulp 271 closes.

Next, pulp: IO, 32, 349f is opened.0 By this operation, the cooling body 22 is cooled with liquid nitrogen, and the cooling bodies 23 and 24 are cooled with liquid helium. Therefore, the surfaces of the cooling bodies 23, 24 are cooled to a cryogenic temperature. After each of the cooling bodies 22, 23, and 24 has been sufficiently cooled, the temperature of the cooling body ztttv is gradually increased by controlling the opening degree of the pulp 36 and decreasing the flow rate of liquid helium. In this way, the adsorptive gas that has condensed and adhered to the surface of the cooling body 25 evaporates, and after this evaporation, the adsorbent gas is cooled to an adjacent extremely low temperature and condenses and adheres to the surface of the cooling body 240 again. An adsorbent gas condensation layer is uniformly formed on the surface of the cooling body 240.

In such a state, among the remaining gas molecules in the room 1, gas molecules other than He and H2 molecules that are relatively easy to condense are kept at an extremely low temperature and condense and adhere to the cooling body 23,
This exhausts the air.

t, e He that does not condense and adhere to the cooling body 23.

Molecules such as H, etc. are adsorbed to the adsorbent gas condensation layer on the surface of the cooling body 240 and are exhausted. Therefore, the degree of vacuum in the room 1 will increase. In this case, the cooling body z2 functions to prevent radiant heat from entering from the room 1 side, and the cooling body 25 functions to prevent radiant heat from entering from the pipe 1g side.

In this way, two extremely low mTrJs that can be temperature controlled.

In other words, a cooling body 25 and a cooling body 24 are provided, and when adsorbent gas is introduced, an adsorbent gas condensation layer is formed on the surface of the cooling body 25, and then this is evaporated and adsorbed onto the surface of the adjacent cooling body 24. A layer of condensed gas is formed.

Therefore, when the adsorptive gas is introduced, the entire amount of the introduced gas can be temporarily condensed on the surface of the cooling body 2j, and it is possible to prevent it from adhering to other surfaces, and when it is transferred to the surface of the cooling body 240, By setting the temperature of the cooling body 25 and the cooling body 24, the total amount of adsorbent gas condensed and adhered to the surface of the cooling body 250 can be well condensed and adhered to the surface of the cooling body 240, resulting in good exhaust performance.
It can be demonstrated.

In this case, the cooling body 25 can act as a heat shield to block the heat t that enters the cooling body 24 from the pipe 1g side by radiation, so that the cooling body 24 and the gas inlet Heat transfer due to radiation between the two can be reduced. This method, the cooling body 24'ff
The consumption of refrigerant such as liquid helium for maintaining the cryogenic temperature can be reduced, and as a result, the operating cost can be reduced by 1.

(9) By setting the cooling body 25 to a size close to that of the cooling body 2411C, the uniformity of the adsorptive gas condensation layer condensed and attached to the cooling body 24 can be greatly improved. Therefore, even in a large-capacity device, there is no need to divide the gas inlet into multiple parts, and as a result, the entire device does not become complicated, bulky, or heavy. Manufacturing costs can also be reduced.

Note that the present invention is not limited to the above-mentioned embodiment. In the following embodiment, the cold shaft body 25 and the cooling body 24 are formed to have the same structure, but they may have different shapes, sizes, etc., as long as they have the above-mentioned functions. It may be changed arbitrarily.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a cryo-soap pump according to an embodiment of the present invention. Mutual...cryosorption pump, 4...container,
5... Gas supply system, 6... Exhaust section, r... Temperature control section, 11j23, 14.26... Cooling body, 19.2
6゜2"i, 28.29...pipe, 21, 30.3
2゜34.16...Pulp.

Claims (1)

[Claims] A cryosorption pump comprising a cryogenic surface in an atmosphere to be evacuated and an adsorbent gas condensation layer for adsorbing and exhausting gas in the atmosphere on the cryogenic surface, the temperature of which can be controlled from outside the atmosphere. No. 1. A second cryogenic surface is provided, and when forming the adsorbent gas condensation layer,
The adsorbent gas introduced from outside the atmosphere is once condensed and adhered to the cryogenic surface of J11, and then the adsorbent gas condensed and adhered is evaporated, and the evaporated adsorbent gas is transferred to the second electrode. By condensing and adhering to a low temperature surface, the above @
2. A cryosorption pump characterized by forming an adsorptive gas condensation layer on the cryogenic surface.