JPS5987883A - Cryostat - Google Patents

Abstract

PURPOSE:To obtain a cryostat suppressed to the utmost an increase of invading heat when a refrigerator is stopped by a method wherein when the refrigerator is stopped, a shielding body being cooled is cooled by sensible heat of vaporized gas of a coolant cooling directly a matter to be cooled. CONSTITUTION:The cooling tube 30 of a shielding body 6 is connected to the circulatory system of a refrigerator, and a cooling tube 31 is equipped to the shielding body 6 as to flow vaporized helium 32 in a vessel 3. When the refrigerator is in the midst of normal operation, a valve 33 is closed as it is, and the valve 33 is opened when operation of the refrigerator stops. When thermal load of 1W exists in the vessel 3, liquid helium 2 evaporates by about 0.05g/s under atmospheric pressure. Because specific heat of vaporized helium is about 5.2J/ (g.K), heat to be absorbed when the temperature rises from 4.2K up to 80K is about 20W. Namely, even when thermal load of 20W exists at the shielding body 6, the temperature of the shielding body 6 can be cooled and held to 80K.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a cryostat that operates at extremely low temperatures, particularly to a cryostat that is suitable for use in superconducting application equipment at temperatures as low as 100 degrees.

[Prior art]

When cooling extremely small superconducting equipment, it is conceivable to use a small refrigerator. FIG. 1 shows an example of a conventional method. 1 is the superconducting coil which is the object to be cooled, and 2 is the superconductor? ! ) Liquid helium to cool the coil τ, 3 is above rt
z> Container containing coil 1 and liquid helium 2, P
, 6fJ is sold as a thermal support 51r inside the vacuum container 4, and is made by inserting the container 3 inside the vacuum container 4 so as to bend it. The liquid nitrogen is cooled down to near the surface of the table.

7 is (first of 1 dere, +4/J with 1 liquid, Heliuno, Ma/Jin, 1 par, helium, which can be divided into 2 with d. To 8, Gihodo Makumapon, The cycle is called the Tsurupei cycle f1.I is a small cold 4 (piston 102 that encloses a regenerator inside the cylinder 9 in the expansion machine of I)
h Tute 4 Tub part 11 #) ((:, HP
There are 4+4bL-C.

Figure 1 shows a two-stage expander;
Cold weather occurred in iM city, and this cooling gear was not removed and cooling 111
2 and 13 are fixed. The refrigerant Heliuno Q supplied through the first refrigerant refrigerant 14 is cooled by the cooling pipe 12, and then the heat exchanger 12 is heated through the cooling body 6. The refrigerant enters the condenser 15, and is then further added to the third heat exchanger 16, where it expands in the expansion valve 17 and partially liquefies.
8, the third heat converter 16 and the second heat converter 1
5. Return through the respective low pressure side of the first heat converter 14 to the room temperature compressor system 19. The heat converter and compressor system are connected by connecting pipes 20 and 21. The compressor system includes a compressor main body, a cooler, a pressure tank, a filter, and a windshield.

When the device is in operation, the injection valve 22 is closed, and the superconducting coil 1 is cooled with liquid helium, which is slightly more vC+a tilt than the liquid in the condenser 18. 11, and heat converters 14, 15.16.
When a trouble occurs in the circulation system using the pressure tI war thread 19, operation of the refrigerator C becomes temporarily impossible. Cooling can be continued by the heat of vaporization of the liquid helium 2 stored in the 11-inch vessel 3. Since the refrigerator is stopped at 1q, the cooling of the helium body 6 is also stopped, and the temperature gradually rises. As a result, heat infiltration increases and liquid helium 2 is consumed more quickly. 4) It is important to suppress the inaccuracies when stopping the refrigerator as much as possible in order to ensure the reliability of the equipment.

[Purpose of the invention]

An object of the present invention is to provide a fried cod 1) in which an increase in heat penetration when the refrigerator is stopped is suppressed as much as possible.

[Summary of the invention]

According to the present invention, a barrier body that is normally cooled by a refrigerator is cooled by the sensible heat of vaporized gas of a refrigerant that directly cools the object to be cooled when the refrigerator is stopped.

[Central example of invention]

Hereinafter, one implementation of the present invention will be explained to a 27th grade student. In FIG. 2, the flow system of the refrigerant is indicated by a line. Different from the conventional example in Fig. 1 fJ, that 11, cooling 3
0 is connected to the circulation system of the refrigerator, and
The point is that the second cooling/fax is attached to the cooling chamber 6 to flow the vaporized helium 32 in the container 3. Pulp 33 when the refrigerator is operating normally.
remains closed, and when the refrigerator stops operating, pulp 3
Open 3.

In addition, the piping 34, the release valve 35, and the safety valve 3 (irl first
Although omitted from the figure, it is used to vent gas during initial cooling and as a safety measure in emergencies.

Now, if the heat load of the IW in the container 3 is rare, the liquid helium 2 evaporates at atmospheric pressure F by approximately 0.05 g/S. The specific heat of vaporized helium is approximately 5.2 J/(g-K), so the heat absorbed when the temperature rises from 4.2 K to 80 K is 0.05x5.2x (80-4,2)L=.

There is 20W. That is, the heat load on the flexible body 6 is 20
This means that even if W is present, the temperature of the flexible body 6 can be maintained at IJCk 80 K. In addition, if the pulp 33 is opened at the time of initial cooling, the sensible heat of the helium that vaporizes in large quantities with the injection of a large amount of liquid helium is used to initially cool the shrinkage body 6, expander 8, and heat exchanger 14. ,15.16
This also has the effect of making it possible to speed up the initial cooling of the water.

〔Effect of the invention〕

As described above, the present invention provides a reliable cryostat that reduces the increase in the temperature of the enclosure when a refrigeration pit is damaged by utilizing the sensible heat of the converted refrigerant, and suppresses the increase in heat intrusion. It has the effect of

[Brief explanation of drawings]

FIG. 1 is a diagram 111 showing all the conventional -S: embodiments, and FIG. 2 is a system diagram showing one embodiment of the present invention. 3... Low-temperature container, 4... Empty container, 6... Shi-yahei body, 8... Expander, 14, 15.16... Heat converter, 18 1 Rokatsu Figure 2

Claims (1)

[Claims] A cooled object that operates at extremely low temperatures, a low-temperature container that houses it,
In a cryostat, which consists of a cage surrounding the surrounding area, an empty container A enclosing these, and a freezing system that supplies cold to a condenser installed in the cryostat, when the cryocooler is stopped, The vaporized gas of the refrigerant liquid for cooling the object to be cooled is directly 1. A cryostat that is characterized by the fact that it is equipped with a cooling system that can be used to cool the body during disasters.