JPS6191978A - Cryostat for superconductive electromagnetic coil - Google Patents

Abstract

PURPOSE:To enable to directly feed the vapor gas of a coolant warmed in the piping into the internal tank by a method wherein the by-pass system piping and the cut-off valve are installed at the normal temperature-side low-temperature part of the low- temperature valve on the liquid injection side and the low-temperature valve is formed into a cross valve-type structure. CONSTITUTION:This cryostat is made in the constitution, wherein a by-pass pipe 11 is provided at the normal temperature-side low-temperature part of the liquid injection-side low-temperature valve 6 of a liquid injecting pipe 4, the by-pass pipe 11 is connected with the normal temperature-side low-temperature part of the recovery- side low-temperature valve 7 of a recovery pipe 5 and a cut-off valve 12 is provided in the middle of the by-pass pipe. The cut-off valve 12 is formed in the structure of the same major-axis valve as the low-temperature valve 7 for making thermal intrusion into the piping reduce, whereby a safety valve 10 for a protection of the piping is limited to one piece, as the liquid injection system and the recovery system are commonly connected by the by-pass system. Furthermore, the liquid injection-side low-temperature valve is formed into the structure of a valve 13 in a cross valve type and is connected with the by-pass pipe 11, which is connected with the recovery pipe. As a result, this cryostat can be made in a constitution, wherein the cut-off valve 2 is not needed.

Description

Detailed Description of the Invention (1) Description of the Technical Field The present invention relates to an inner tank for storing a cryogenic refrigerant for housing and cooling a superconducting electromagnetic coil, an outer tank for thermally surrounding the inner tank, and an outer tank. The present invention relates to the structure of a cryogenic container that includes a liquid injection pipe and a recovery pipe that are provided through an inner tank and a cryogenic valve that closes off the inner tank.

(2) Prior art and its problems A conventional cryogenic container will be explained using as an example a cryogenic container for storing liquid helium attached to a superconducting magnet device or the like. Since liquid helium is a scarce resource, expensive, and has low evaporation rate, it is important to minimize the amount of heat that enters the inner tank of the cryogenic container that stores liquid helium to suppress evaporation of liquid helium and use it effectively. is desirable. Therefore, in order to reduce the amount of heat intrusion in cryogenic containers, the entire inner tank must be
￥ F It is possible to have a double structure in which it is stored in an outer tank made of nitrogen, or to create an intermediate cooling layer between the inner and outer tanks, or to create a super-flit structure.
Efforts have been made to use kS material in combination, or to use a support device identified as the outer tank to support the inner tank 2 with a material having good thermal insulation properties. In addition, in the injection system piping that sends liquid helium to the inner tank and the recovery system piping that collects evaporated helium gas, if the inner tank is closed at the normal temperature end of the outer tank side, the liquid helium shakes out. , heat intrusion into the inner tank due to liquid jumping into the piping and convection of helium gas in the piping, etc. Therefore, a low temperature valve that can be shut off at the low temperature section is installed on the above piping to prevent the flow of heat into the inner tank. The amount of heat intrusion is suppressed as much as possible. In particular, the above-mentioned structure is important when a small refrigerator is installed and the superconducting magnet is operated continuously, such as an on-board superconducting magnet in a floating railway.

FIG. 2 shows the configuration of a cryogenic container having the above structure.

The inner tank 1 is insulated and held inside the outer tank 2, and can store liquid helium 3, which is filtered by a refrigerant.

Liquid helium passes through the liquid injection pipe 4 and is stored in the inner tank 1, and the helium gas evaporated in the inner tank 1 is recovered through the recovery pipe 5. 6.7 is a low temperature valve that closes off the inner tank in the low temperature section. Valve 8.9 is an inlet/outlet valve for liquid injection and collection, and shuts off each system in the normal temperature section. Note that the valves 8.9 may not be directly attached to the device, but may be installed at other locations. A safety valve 10 is provided for the safety of the piping system. In addition, piping connected to superelectric magnet devices, etc., heat shield plates, various boats, sensors, etc. are also installed, but they are omitted to avoid complication of explanation.

In the cryogenic container described above, when the inner tank is closed off with a cryogenic valve, the liquid injection pipe 4 is cut off from the inner tank by the cryogenic valve 6, so cooling is not sufficient and heat may enter from the outer tank. The temperature of the 4-fi pipe rises and becomes stable with a certain temperature gradient between the outer tank and the inner tank. Even if the pipe 4 between the liquid injection inlet valve 8 and the low-temperature valve 6 is evacuated to reduce heat intrusion due to heat transfer of helium gas, if the cut-off time becomes longer, the pipe 4 will become weaker due to heat conduction. It will have a temperature gradient like the one above.

Therefore, when additional liquid helium is injected after the inner tank is closed and kept cold, the temperature of the liquid injection pipe 4 has increased as described above, so the liquid helium that is delivered will not be able to reach the initial stage of the paper. is sent to the inner tank while cooling the tube 4. By the way, since liquid helium has a low latent heat of vaporization, it becomes a high-temperature helium gas until the tube 4 is cooled at the initial stage of injection. It will be sent directly into the inner tank. Since the helium gas sent into the inner tank has a high degree of IA, the liquid helium stored in the inner tank is evaporated and wasted. In addition, at the beginning of injection, a large amount of high-temperature helium gas is sent into the inner tank, so the stored liquid helium rapidly evaporates and becomes cass helium, causing an excessive pressure rise in the inner tank. There is little danger of it posing a problem. Therefore, it was necessary to adjust the valve during refilling to prevent internal pressure from increasing.

(3) Purpose of the invention Closing off the inner tank with a low-temperature valve - In a low-temperature container, when adding liquid, the refrigerant that accumulates in the pipe and becomes evaporative gas is not directly sent into the inner tank. Provide cryogenic container construction.

(4) Direct mounting of the invention In the cryogenic capacity of the present invention, the bypass system piping and the shutoff valve are stepped to the low temperature part on the room temperature side of the low temperature valve, so that when additional liquid is injected, After pre-cooling the pipe, the liquid is injected into the inner tank, so that the evaporated gas of the refrigerant filtered in the pipe is not sent directly to the inner tank. Furthermore, by using a structure with 30,000 low-temperature valves on the liquid injection side and connecting the bypass system piping to the recovery system piping, the above effects can be expected without increasing the number of valves.

(5) Embodiments of the Invention (Structure of the Embodiments) The extremely low temperature container of the present invention includes a bypass pipe that connects a liquid injection pipe and a recovery pipe to the low temperature section on the room temperature side of a low temperature valve, and a cut-off box for opening and closing the bypass pipe. shall be of a configuration in which the That is, as shown in FIG. 1, a bypass pipe 11 is provided from the room temperature side low temperature part of the liquid injection side low temperature valve 6 of the liquid injection pipe 4, and is connected to the room temperature side low temperature part of the recovery side low temperature valve 7 of the recovery pipe 5. , a shutoff valve 12 is provided in the middle of the bypass pipe. The shutoff valve 12 is a *shaft valve similar to a low temperature valve in order to reduce heat intrusion into the piping.

In addition, when the inner tank is closed, by opening the shutoff valve 12, the liquid injection system and the collection system are commonly connected by the bypass system, so one safety valve 10 is installed for piping security. I have to.

Generally, in the present invention, since the number of valves is not increased, the third
As shown in the figure, the liquid injection side low temperature valve is a three-way valve type valve 13,
By connecting to the bypass pipe 11 that connects to the recovery pipe, a configuration that does not require the shutoff valve 12 can be achieved. The three-way valve 13 of the low-temperature valve on the liquid injection side has a structure shown in FIG. 4. That is, between the valve seat 13b of the low temperature valve to the inner tank and the insertion type bypass system valve seat 13C? The structure is such that the flow path can be branched by moving the valve body 13a up and down. Also,
A sealing material 14 closes off the temperature to the normal temperature side.

(Operation and effect of the embodiment) In the low-temperature container according to the present invention shown in FIG. 3, additional 7JO liquid injection after closing the inner tank is performed by first opening the shut-off valve 12,
After cooling liquid helium to the bypass pipe 11 and cooling the liquid supply pipe 4, by opening the low temperature valve 6 on the liquid injection side, liquid helium is directly injected into the inner tank 1, and the adult helium stored in the inner tank is Additional injection is performed without evaporating the liquid.

Further, since the liquid helium stored in the tf is not evaporated, a sudden pressure increase in the inner tank due to evaporated gas is not caused.

(6) Other embodiments Furthermore, as shown in FIG.
3, the above-mentioned effect can be achieved without increasing the number of valves. Furthermore, as shown in Part 5, the operation of the Vc 3-way valve is such that when the position of the valve body 13a is indicated by a solid line, it indicates that liquid is being injected into the inner tank, and the liquid is injected into the inner tank along the thread path indicated by the solid line arrow. Ru. The valve element 13a is shut off from the bypass system by pressing the insertable bypass system valve seat 13c'C. When the position of the valve body 13a is indicated by the dotted line, the precooling state of the bypass system is also 17<, which indicates the inner tank closed state, and precooling is performed along the path indicated by the dotted arrow. Closing with the inner tank 1 is performed by pressing the valve body 13a against the valve seat 13b.

(7) As described above in the effect of the invention, by installing the bypass system in the low temperature part on the room temperature side of the low temperature valve and pre-cooling the piping before injecting liquid, additional liquid injection after the inner tank is closed is possible. This can be done without evaporating the stored liquid helium. Furthermore, since the stored liquid helium does not cause rapid evaporation, a sudden pressure increase in the inner tank can be prevented. Furthermore, if the shutoff valve of the bypass system is opened when the inner tank is closed, the liquid injection system and the recovery system are commonly connected through the bypass system, so the number of safety valves for protecting the piping can be reduced to one.

Furthermore, by using a three-way valve as the low-temperature valve on the liquid injection side, the same effects as described above can be obtained without increasing the number of valves. Furthermore, since the number of valves does not increase, there is no increase in the amount of heat entering from the well, and a greater effect can be expected.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a cryogenic container according to an embodiment of the present invention;
Fig. 2 is a block diagram of a conventional cryogenic container, Fig. 3 is a block diagram of a cryogenic vessel according to another embodiment, Fig. 4 is a structural diagram of a three-way valve used in the present invention, and Fig. 5 is a structural diagram of a three-way valve used in the present invention. FIG. 7 is another structural diagram of the side valve. l... Inner tank 2... Outer tank 3... Liquid helium 4... Liquid injection system piping 5...
・Recovery system piping '6'... Liquid injection side low temperature valve 7... Recovery side low temperature valve 8... Liquid injection inlet valve 9... Recovery outlet valve
10...Safety valve 11...Bypass system piping 1
2... Shutoff valve 13... Three-way valve 13a... Valve body 13b... Valve seat 13c... Bypass system valve seat 14... Seal material 15... Coil spring 16...
Benbo (7317) Representative Patent Attorney Noriyuki Chika (and 1 others)
Figure 1, Figure 2, Figure 3, Figure 4

Claims (2)

[Claims] (1) Consisting of an inner tank that stores cryogenic refrigerant liquid to cool the superconducting electromagnetic coil, and an outer tank at room temperature that adiabatically surrounds and stores this, the refrigerant liquid is passed through the inner and outer tanks. A liquid injection pipe for injecting liquid and a recovery pipe for recovering evaporated gas of the refrigerant liquid, each pipe having a low-temperature shutoff valve extending to the outer side of the outer tank and an inlet valve provided at the outer side of the inner tank, A superconducting electromagnetic coil characterized in that a bypass pipe is provided to directly connect the pipes on the normal temperature side of the low temperature valve, and a shutoff valve is provided in the middle of the bypass pipe to pre-cool the liquid injection pipe outside the inner tank. Cryogenic container. (2) A cryogenic container for a superconducting electromagnet coil according to claim 1, wherein a three-way valve is provided in place of the shutoff valve provided in the bypass pipe and the low temperature valve provided in the liquid injection pipe.