JPH07229667A - Cooler using low-temperature liquefied gas - Google Patents

Abstract

PURPOSE:To provide a cooler in which an efficient cooling operation can be executed, a manufacturing cost, an operating cost can be decreased and low- temperature liquefied gas is used. CONSTITUTION:A cooler (shroud 12) is constructed by providing a plurality of fin tubes 13 having low-temperature liquefied gas channels between a pair of upper and lower manifolds 14 and 15. A low-temperature liquefied gas vessel 16 having a low-temperature liquefied gas supply tube 19 and a vaporized gas exhaust tube 20 is provided above the shroud 12. The vessel 16 is connected to the manifold 15 by a low-temperature liquefied gas introducing tube 17, and an upper part of the vessel is connected to the manifold 15 by a return tube 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device using low-temperature liquefied gas, and more specifically, a shroud used in a space environment test device, a panel-like cooler such as a cryopanel of a cryopump, or the like. The present invention relates to an apparatus for cooling with a low temperature liquefied gas such as liquid helium.

[0002]

2. Description of the Related Art As shown in FIG. 6, on the inner surface of a vacuum container 1 of a space environment test apparatus, in order to simulate the cold darkness of space in the vacuum container, it is cooled to 100 K or less by liquid nitrogen which is a low temperature liquefied gas. The heat absorption wall called shroud (hereinafter,
2 is called shroud). In a large apparatus, a large number of fin tubes 5 are provided between a pair of upper and lower manifolds 3 and 4 with fins around the tubes that serve as low-temperature liquefied gas flow paths.
A shroud 2 having a structure obtained by welding and joining is used. These shrouds 2 are manufactured in various shapes according to the shape of the vacuum container 1, and a plurality of shrouds 2 are used in one vacuum container 1.

In order to cool these shrouds 2 uniformly, the conventional apparatus employs a single-phase flow cooling system equipped with a liquid nitrogen storage tank 6, a liquid nitrogen pump 7, a pressure regulator 8 and a gas-liquid separator 9. Was there. In this single-phase flow cooling system, the liquid nitrogen stored in the liquid nitrogen storage tank 6 at around atmospheric pressure is compressed by the liquid nitrogen pump 7 into the supercooled liquid nitrogen, and the supercooled liquid nitrogen is It is introduced from below into each fin tube 5 through the lower manifold 4, and the upper manifold 3
The gas-liquid separator 9 separates and discharges the vaporized gas, and circulates only liquid nitrogen.

A cryopump using liquid helium as a cooling source is known as one having a panel-shaped cooler such as the shroud. Similar to the shroud, this cryopump uses a cryopanel in which fin tubes having a liquid helium flow path are combined to form a panel, and the cryopanel is cooled with liquid helium to trap hydrogen and the like on the cooling surface. To do.

[0005]

In the shroud having the above-described structure, since the supercooled liquid nitrogen compressed by the liquid nitrogen pump 7 is introduced into the fin tubes 5 of the shroud 2, the manifold forming the shroud 2 will be described. There is a disadvantage that the shroud 2 is vibrated because the liquid nitrogen pump 7 circulates a large amount of liquid nitrogen. Further, conventionally, since the sensible heat of liquid nitrogen is used, it is necessary to circulate a large amount of liquid nitrogen and it is necessary to use a pipe having a large diameter. Further, also in the cryopump, it is necessary to uniformly and efficiently cool the cryopanel.

Therefore, the present invention is capable of performing efficient cooling operation in a cooling device such as a shroud of a space environment test device or a cryopanel of a cryopump, which cools by using a low temperature liquefied gas. It is an object of the present invention to provide a cooling device using a low temperature liquefied gas that can reduce the cost and the operating cost.

[0007]

In order to achieve the above-mentioned object, a cooling device using low temperature liquefied gas of the present invention is provided with a low temperature liquefied gas flow path which constitutes a cooler between a pair of upper and lower manifolds, and A low-temperature liquefied gas container provided with a low-temperature liquefied gas supply pipe and a vaporized gas exhaust pipe is provided above the low-temperature liquefied gas passage, and a low-temperature liquefied gas container bottom and a lower manifold are connected to the low-temperature liquefied gas introduction pipe. Connect with
It is characterized in that the upper part of the container and the upper manifold are connected by a return pipe.

Also, the cooling device is characterized in that the cooling device is composed of a plurality of fin tubes, and the cooling device is composed of a plurality of cooling devices composed of the plurality of fin tubes. It also includes things. Furthermore, it also includes a cooling device including a plurality of coolers as one block. It is characterized in that they can be operated independently.

Further, according to the present invention, in the above structure, the lower manifold is provided with a low temperature liquefied gas discharge pipe, and the lower manifold is provided with a warming gas supply pipe for heating the low temperature liquefied gas passage. In addition, the upper manifold and the lower manifold are connected by a warmed gas circulation system including a circulation blower and a heating means.

Further, these pipes and the like are characterized in that the discharge and heating operations can be independently performed for each cooler composed of the plurality of fin pipes. Furthermore, it is characterized in that the above operation can be performed independently for each of the blocks.

[0011]

[Operation] According to the above configuration, the low-temperature liquefied gas that is the cooling medium is supplied from the bottom of the low-temperature liquefied gas container to the low-temperature liquefied gas flow path that serves as the cooling unit of the cooling device through the lower manifold. The gas vaporized in the flow path returns from the upper manifold to the gas phase portion in the upper part of the container and is discharged from the exhaust pipe. That is, the low-temperature liquefied gas in the low-temperature liquefied gas container flows down by its own weight according to the amount of gas vaporized in the low-temperature liquefied gas passage and flows into the low-temperature liquefied gas passage.

The maximum pressure of the low temperature liquefied gas can be set as low as the atmospheric pressure plus the liquid head in the lower manifold portion at the bottom of the apparatus, and the design pressure of the apparatus can be lowered. Furthermore, since a pump is not used to supply the low-temperature liquefied gas, fluid vibration does not occur, and the latent heat of the low-temperature liquefied gas is used for cooling, so that the required amount of the low-temperature liquefied gas can be reduced.

Further, by providing the low-temperature liquefied gas discharge pipe in the lower manifold, the low-temperature liquefied gas in the low-temperature liquefied gas passage can be easily recovered at the end of the cooling operation, and the low-temperature liquefied gas is supplied to the lower manifold. By providing the above-mentioned supply pipe, it is possible to easily heat the low-temperature liquefied gas channel to normal temperature. In particular, by connecting the upper manifold and the lower manifold with a warming gas circulation system equipped with a circulation blower and heating means, it is possible to warm the low-temperature liquefied gas flow path while circulating the warming gas. The usage amount of can be significantly reduced.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the embodiments shown in the drawings. First, FIG. 1 shows the first embodiment of the present invention.
An example is shown in which the present invention is applied to a shroud of a space environment test device.

Vacuum container 11 constituting a space environment test apparatus
The shroud 12 provided along the wall surface of the fin is a welded joint of a large number of fin tubes 13 having liquid nitrogen flow paths for cooling the shroud 12 to a predetermined temperature. The lower ends are welded to the upper manifold 14 and the lower manifold 15, respectively.

Above the shrouds 12, a liquid nitrogen container 1 for storing liquid nitrogen to be supplied to each shroud 12 is provided.
6 is provided for each shroud 12. In each of the liquid nitrogen containers 16, a liquid nitrogen introducing pipe 17 that connects the bottom of the container 16 to the lower manifold 15, a return pipe 18 that connects the upper part of the container 16 to the upper manifold 14, A liquid nitrogen supply pipe 19 for supplying liquid nitrogen into the container 16 and an exhaust pipe 20 for discharging the nitrogen gas in the container 16 are provided. Furthermore, each liquid nitrogen container 1
6 is provided with a liquid level gauge (LC) 21 for detecting the liquid level of the liquid nitrogen in the container 16, and the liquid nitrogen supply pipe 19 is provided with a liquid nitrogen supply pipe according to the detection value of the liquid level gauge 21. Valves 22 for adjusting the amount of liquid nitrogen supplied from 19 are respectively provided.

The liquid nitrogen for cooling the shroud 12 is branched from the liquid nitrogen storage tank 23 through the liquid nitrogen supply main pipe 24 to the liquid nitrogen supply pipe 19 of each liquid nitrogen container 16, and a valve 22 is provided.
And is supplied into the liquid nitrogen container 16 through.

The liquid nitrogen in the liquid nitrogen container 16 flows down the liquid nitrogen introducing pipe 17 by its own weight and flows into the fin pipes 13 of the shroud 12 from the lower manifold 15 to cool the shroud 12. The nitrogen gas vaporized by cooling the shroud 12 rises in the fin pipe 13 and collects in the upper manifold 14, and returns to the liquid nitrogen container 16 via the return pipe 18. At this time, the nitrogen gas returning to the liquid nitrogen container 16 flows into the liquid nitrogen container 16 together with the liquid nitrogen due to its levitation force. The nitrogen gas and the liquid nitrogen are separated into gas and liquid in the liquid nitrogen container 16. The liquid nitrogen circulates through the path again, and the nitrogen gas is discharged from the exhaust pipe 20 through the exhaust main pipe 25.

Thus, when the shroud 12 is cooled, the liquid nitrogen flows down from the liquid nitrogen container 16 through the liquid nitrogen introducing pipe 17 into the fin pipe 13 by the action of gravity.
The return pipe 18 together with the nitrogen gas vaporized in the fin pipe 13
From the liquid nitrogen container 16 into the liquid nitrogen container 16.

Therefore, since the liquid nitrogen can be supplied only by gravity, a pump for pressurizing the liquid nitrogen is not required, and the liquid nitrogen container 16 is operated at about the atmospheric pressure, so that the maximum pressure is the atmospheric pressure plus the liquid head. Since it can be lowered to a certain degree, it is not necessary to give high pressure resistance to the fin tubes 13 and the upper and lower manifolds 14 and 15 of the shroud 12, and the design pressure of the shroud 12 can be lowered,
The device cost can be reduced.

Since the latent heat of the liquid nitrogen is used for cooling the shroud 12, the shroud 12 can be efficiently cooled and the amount of liquid nitrogen supplied to the shroud 12 can be reduced. As a result, the liquid nitrogen storage tank 23
Therefore, it is possible to reduce the pipe diameter and the valve of the system for supplying the liquid nitrogen to the liquid nitrogen container 16. Furthermore, since it is not necessary to circulate a large amount of liquid nitrogen in the shroud 12,
With the omission of the pump, fluid vibration can be suppressed,
It is especially suitable for environmental tests that are sensitive to vibration.

Moreover, since the liquid nitrogen can be evenly supplied to each shroud 12 by simply keeping the liquid nitrogen level in each liquid nitrogen container 16 substantially constant, as shown in this embodiment. This can be easily performed by providing the liquid nitrogen container 16 with the liquid level gauge 21 and the liquid nitrogen supply pipe 19 with the valve 22 which opens and closes in conjunction with the liquid level gauge 21. Further, since the liquid nitrogen container 16 and the valve 22 are provided for each shroud 12, the respective shrouds can be operated independently of each other without affecting each other.

FIG. 2 shows a second embodiment of the present invention, in which a system for heating the shroud to room temperature after the test is provided is provided. The same elements as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, a system for discharging liquid nitrogen from the shroud 12 and a system for heating the shroud 12 are added to the structure shown in the first embodiment. That is, in the lower manifold 15 of each shroud 12,
A liquid nitrogen discharge pipe 32 having a valve 31 is provided, and
The exhaust pipe 20 and the lower manifold 15 are connected by a heating gas circulation system 35 having a circulation blower 33 and a heater 34.

When the shroud 12 cooled with liquid nitrogen as described above is heated to room temperature after the test is completed, first, the main valve (not shown) of the liquid nitrogen supply main pipe 24 or each liquid nitrogen supply is supplied. After closing the valve 22 of the pipe 19, the valve 31 of the liquid nitrogen discharge pipe 32 is opened to discharge the liquid nitrogen in each fin pipe 13 of the shroud 12 from the liquid nitrogen discharge pipe 32 through the discharge main pipe 36.

When the discharge of liquid nitrogen is completed, the exhaust pipe 20
37 and the valve 31 of the liquid nitrogen discharge pipe 32 are closed, and branch pipes 38 to the respective shrouds 12 of the warm gas circulation system 35,
The valves 40 and 41 provided in 39 are opened, and the circulation blower 33 and the heater 34 are operated. As a result, the gas (nitrogen gas) sent from the circulation blower 33 to the pipe 42 is heated by the heater 34, and then the branch pipe 39 and the valve 4 are provided.
1, lower manifold 15, fin pipe 13, upper manifold 14, return pipe 18, liquid nitrogen container 16, exhaust pipe 2
Circulation blower 3 through 0, valve 40, branch pipe 38, pipe 43
The shroud 12 is heated by the heated nitrogen gas which is circulated to the No. 3 and heated by the heater 34. A part of the heated nitrogen gas flows from the liquid nitrogen introducing pipe 17 to the liquid nitrogen container 16,
The liquid nitrogen introducing pipe 17 and the liquid nitrogen container 16 are heated and circulated in the exhaust pipe 20. Nitrogen gas to each shroud is monitored by monitoring the shroud temperature, allowing valve 41
Adjusted by

As described above, by providing the lower manifold 15 with the liquid nitrogen discharge pipe 32, the liquid nitrogen existing in the shroud 12 or the like can be discharged from the discharge main pipe 36 and recovered after the test is completed. It is possible to easily perform discharge collection.

Further, by connecting the upper manifold 14 and the lower manifold 15 with a heating gas circulation system 35 having a circulation blower 33 and a heater 34, the nitrogen gas remaining in the system is circulated and used to shroud. 12 can be heated. Further, the pressure of the shroud during heating is properly adjusted by the nitrogen gas supply valve 44 and the discharge valve 45 shown in FIG.

The circulation direction of the heated nitrogen gas can be reversed. Further, each shroud 12 can be operated independently of each other, and at that time, each operation can be performed without affecting other shrouds.

Further, in this embodiment, the valve 3 is provided in each of the exhaust pipe 20, the liquid nitrogen discharge pipe 32, and the branch pipes 38, 39.
Although 7, 31, 40 and 41 are provided, the installation position of the valve can be set arbitrarily. For example, instead of these valves,
The exhaust main pipe 25, the discharge main pipe 36, and the pipe 43 are respectively shown in FIG.
Valves 46, 47 and 48 may be provided as indicated by imaginary lines.

It is also possible to connect another heating gas supply system to the lower manifold 15 to discharge the gas after heating the shroud 12 from the exhaust pipe 20, but as described above, the heating gas circulation system is used. By providing 35 to circulate the warmed gas, the amount of nitrogen gas required to raise the temperature of the shroud 12 to a predetermined temperature can be significantly reduced.

FIG. 3 shows a third embodiment of the present invention, in which the liquid nitrogen container is separated when the shroud is heated after the test is completed so that the heating time can be shortened. It is a thing. The same elements as those in each of the above-described embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, partition valves 51 and 52 are provided in the liquid nitrogen introducing pipe 17 connecting the liquid nitrogen container 16 and the lower manifold 15 and the return pipe 18 connecting the liquid nitrogen container 16 and the upper manifold 14, respectively. It is provided.

By providing the sluice valves 51 and 52 in this manner, the sluice valves 51 and 52 are closed when the liquid nitrogen in the shroud 12 is discharged and the shroud 12 is heated, so that the shroud 12 and the liquid nitrogen container 16 are separated from each other. The liquid nitrogen can be separated and the liquid nitrogen can be discharged from the shroud 12 and the shroud 12 can be heated while the liquid nitrogen is stored in the liquid nitrogen container 16. As a result, the time required for discharging and heating the liquid nitrogen can be shortened.

Also in the case of this embodiment, as in the case of the above embodiment,
Driving operations can be performed independently for each shroud without affecting each other.

Further, the liquid nitrogen container 16 and the sluice valve 5
By installing 1,52 in a heat insulating container different from the vacuum container 11, liquid nitrogen can be supplied to the liquid nitrogen container 16 regardless of the operating state of the vacuum container 11, so the shroud 12 is cooled. The time required for doing this can also be shortened.

FIG. 4 shows a fourth embodiment of the present invention, in which one liquid nitrogen container is installed for a plurality of shrouds. The same elements as those in each of the above-described embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

In the present embodiment, four shrouds 12 having the same structure as described above are combined with one liquid nitrogen container 16, and the lower manifold 15 and the liquid nitrogen container 16 of each shroud 12 are provided with liquid nitrogen introduction. The branch pipe 61 and the liquid nitrogen introduction main pipe 62 are connected to each other, and the upper manifold 14 and the liquid nitrogen container 16 are connected to each other via a return branch pipe 63 and a return main pipe 64. The liquid nitrogen introduction main pipe 62 and the return main pipe 64 are respectively connected to the sluice valve 5
1, 52 are provided similarly to the above, and the return branch pipe 63
Is connected to the suction side pipe 43 of the circulation blower 33 of the warm gas circulation system 35 via a valve 65.

By connecting a plurality of shrouds 12 to one liquid nitrogen container 16 as described above, the number of installed liquid nitrogen containers 16 and liquid level gauges 21, valves 22 and the like associated therewith can be reduced to reduce the apparatus cost. It can be reduced. Also,
When a large number of shrouds are provided as in a large apparatus, the shroud of the entire apparatus may be divided into a plurality of blocks, and the liquid nitrogen container 16 may be provided for each block. In this case as well, it is needless to say that the shroud can be independently operated and the driving operation can be performed without affecting other blocks, as in the above embodiment.

In each of the above-mentioned embodiments, the shroud installed in the vacuum container of the space environment test apparatus has been described as an example of the panel cooler cooled by the low temperature liquefied gas, but the present invention is not limited to this. Similarly to the shroud, it can be applied to various devices that cool a panel-shaped cooler with a low-temperature liquefied gas.

For example, FIG. 5 shows a fifth embodiment of the present invention, in which a cryopanel of a cryopump is cooled by liquid helium generated in a helium liquefier refrigerator and operated in a closed cycle. ing.

That is, the liquid helium generated in the helium liquefaction refrigerator 71 is supplied to the liquid helium container 76 from the liquid helium main pipe 72 through each supply pipe 73 and the valve 75 controlled by the liquid level gauge 74, and then the partition It is introduced from the valve 77 and the liquid helium introducing pipe 78 into the fin pipe 81 which constitutes the cryopanel 80 through the lower manifold 79, and cools the cryopanel 80. The helium gas returned from the cryopanel 80 to the liquid helium container 76 through the upper manifold 82, the return pipe 83, and the partition valve 84 and separated into gas and liquid is supplied to the helium gas return pipe 85 and the return main pipe 86 from the upper part of the liquid helium container 76. After that, the liquid is circulated to the helium liquefier refrigerator 71.

The cryopanel 8 after the cooling operation is completed
To recover the liquid helium in 0, the liquid helium is extracted from the valve 87 connected to the lower manifold 79, and the helium compressor 92 through the liquid helium recovery pipe 88, the helium warmer 89, the helium refining facility 90, and the buffer tank 91.
It can be done by inhaling. The helium refining equipment 90 is provided to remove, with an adsorbent or the like, air taken in from the suction side of the compressor and a small amount of water mixed in from the gas bag accumulated for a long period of time. It is a thing.

Further, the cryopanel 80 is heated by heating the helium gas at an appropriate temperature in the helium liquefying refrigerator 71 with the both partition valves 77 and 84 closed. It is introduced into the cryopanel 80 through the lower manifold 79, and the upper manifold 82,
It can be performed by circulating it through the valve 95 and the heated helium return pipe 96. Similarly, the pre-cooling at the start of the cooling operation can also be performed by circulating the helium gas at an appropriate temperature in the helium liquefier refrigerator 71 through the cryopanel 80.

Generally, the heating / regeneration of the cryopanel 80 is performed by heating to a temperature at which hydrogen adhering to the cryopanel 80 can be released, for example, about 18 K, and pre-cooling after the regeneration is performed with helium. It is performed by introducing about 4.5 K of helium gas at the JT valve outlet in the liquefying refrigerator 71 into the cryopanel 80.

Also in the case of this embodiment, as in the above-mentioned respective embodiments, the cooling operation and the heating operation can be carried out independently for each cryopanel without affecting each other.
In particular, in the case of a neutron particle injector, the cryopump chambers are independently provided and the cryopanels are housed in the chambers, respectively, so that this effect is great.

[0047]

As described above, in the cooling device of the present invention, the low temperature liquefied gas container is provided above the low temperature liquefied gas flow path constituting the cooler to cool the low temperature liquefied gas to cool the cooler. The gas is supplied from the bottom of the gas container, and the gas vaporized in the low temperature liquefied gas channel is returned to the upper part of the container before being exhausted, so the low temperature liquefied gas in the low temperature liquefied gas container is gravity fed to the low temperature liquefied gas channel. Therefore, it is not necessary to compress and supply the low temperature liquefied gas with a pump, and since the pressurized low temperature liquefied gas is not used, the design pressure of the device can be set low.

Furthermore, since the latent heat of the low-temperature liquefied gas is used for cooling, the cooling efficiency can be improved, the consumption of the low-temperature liquefied gas can be reduced, and the pipes, valves, etc. can be reduced in diameter, and the equipment can be reduced. The cost and operating cost can be reduced.

Further, by providing the lower manifold with a low-temperature liquefied gas discharge pipe, the low-temperature liquefied gas can be easily discharged at the end of the cooling operation, and by providing the lower manifold with a heating gas supply pipe, the operation is completed. The subsequent heating of the cooler can be performed in a short time. Further, by providing the heating gas circulation system, it is possible to reduce the consumption amount of the heating gas required for heating the cooler.

[Brief description of drawings]

FIG. 1 is a system diagram showing a first embodiment in which the present invention is applied to a shroud cooling system in a space environment test apparatus.

FIG. 2 is a system diagram showing a second embodiment of the same.

FIG. 3 is a system diagram of a third embodiment of the same.

FIG. 4 is a system diagram showing a fourth embodiment of the same.

FIG. 5 shows a fifth embodiment of the present invention and is a system diagram showing an embodiment in which the present invention is applied to a cryopump.

FIG. 6 is a system diagram showing an example of a shroud cooling system in a conventional space environment test apparatus.

[Explanation of symbols]

11 ... Vacuum container, 12 ... Shroud, 13 ... Fin tube,
14 ... upper manifold, 15 ... lower manifold, 1
6 ... Liquid nitrogen container, 17 ... Liquid nitrogen introduction pipe, 18 ... Return pipe, 19 ... Liquid nitrogen supply pipe, 20 ... Exhaust pipe, 21 ... Liquid level gauge, 23 ... Liquid nitrogen storage tank, 32 ... Liquid nitrogen discharge pipe, 33
... Circulation blower, 34 ... Heater, 35 ... Heating gas circulation system, 51, 52 ... Gate valve, 71 ... Helium liquefier refrigerator, 77 ... Cryopanel

Claims (4)

[Claims] 1. A low-temperature liquefied gas flow path forming a cooler is provided between a pair of upper and lower manifolds, and a low-temperature liquefied gas supply pipe and a vaporized gas exhaust pipe are provided above the low-temperature liquefied gas flow path. A low-temperature liquefied gas container is provided, the low-temperature liquefied gas container bottom part and the lower manifold are connected by a low-temperature liquefied gas introduction pipe, and the container upper part and the upper manifold are connected by a return pipe. Cooling device used. 2. The cooling device using low temperature liquefied gas according to claim 1, wherein the lower manifold is provided with a low temperature liquefied gas discharge pipe. 3. The cooling device using low-temperature liquefied gas according to claim 1, wherein the lower manifold is provided with a heating gas supply pipe for heating the low-temperature liquefied gas passage. 4. The cooling method using low-temperature liquefied gas according to claim 1, wherein the upper manifold and the lower manifold are connected by a warm gas circulation system including a circulation blower and heating means. apparatus.