JPH05332655A - Mounting device for cryogenic refrigerator - Google Patents

Abstract

PURPOSE:To effectively prevent invasion of heat into a Dewar by forming a plurality of packing bearers and packing fixtures stepwisely on opposed surfaces of opposed flanges protruding on a peripheral edge of an insertion inlet of the Dewar and an outer periphery of an insertion part of a refrigerator, and interposing the packings under pressure therebetween. CONSTITUTION:An insertion part 30 of a cryogenic refrigerator is inserted into an insertion inlet 5 opened at a wall of a Dewar for storing liquid helium to cool and hold a coil of a superconducting magnet at a critical temperature in a linear motor car, etc., liquid helium gas vaporized in the Dewar is guided to the refrigerator, condensed and returned into the Dewar. In this case, opposed flanges 31, 34 protrude from a peripheral edge of the inlet 5 and an outer periphery of the part 30 of the Dewar 1. A plurality of packing bearers 33 and packing fixtures 36 are respectively stepwisely formed on the opposed surfaces of the other flanges 31, 34 to the flanges 34, 31, and packings 37 are interposed under pressure between the both 33 and 37 thereby to form a closed space 40 between the packings 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting device for mounting a cryogenic refrigerator for cooling and liquefying a refrigerant gas evaporated in a dewar to a dewar for storing a liquefied refrigerant at a cryogenic level.

[0002]

2. Description of the Related Art In recent years, attention has been paid to a linear motor car that uses a superconducting magnet to float a vehicle body on a track for propulsion. In this superconducting magnet, liquid helium stored in the dewar is used to cool and maintain the superconductor used for the coil at the critical temperature.Since this liquid helium evaporates in the dewar, this evaporated helium gas Must be cooled and condensed to be liquefied, and a cryogenic refrigerator is used for this purpose.

As an example of a refrigerator for cooling the helium gas to a condensing temperature, there is conventionally known, for example, US Pat. No. 4,223.
No. 540, etc., a pre-cooling refrigerator and a J-
There is a refrigerator combined with a T refrigerator. The pre-cooling refrigerator is composed of a refrigerating machine such as an improved Solvay cycle or a GM cycle (Gifford McMahon cycle).
The helium gas (refrigerant gas) compressed by the compressor is adiabatically expanded by the expander, and the temperature drop of the gas causes the heat station to generate a cryogenic level of cold.

On the other hand, the JT refrigerator has a precooler for precooling by exchanging heat between the helium gas supplied from the compressor and the heat station of the expander in the precooling refrigerator, and the helium gas is used as a joule gas. Thomson inflates J-
A T-valve is connected to a closed circuit, and the helium gas from the compressor is pre-cooled by a pre-cooler, and the pre-cooled helium gas is expanded by Joule-Thomson with the J-T valve to achieve 4K level coldness. Is generated.

When the evaporated helium gas in the dewar is cooled by the refrigerator, a part of the helium circuit of the JT refrigerator is opened on the downstream side of the JT valve to form an open cycle, and the open end is opened. The vaporized helium gas in the dewar was made to communicate with each other through the gas suction pipe and the liquid discharge pipe, and the evaporated helium gas in the dewar was sucked into the helium circuit of the JT refrigerator and compressed by the compressor. The helium gas is expanded by a JT valve to be cooled and liquefied, and this liquid helium is returned to the inside of the dewar through a liquid discharge pipe.

In this case, a structure called a plug-in structure is adopted in which the refrigerator is detachably attached to the dewar in consideration of maintainability of the refrigerator. That is, in this structure, with respect to the dewar housed inside the radiation shield in the vacuum container, a horizontal pipe reaching from the wall of the dewar to the wall of the vacuum container through the radiation shield is arranged in a penetrating state, and the interior is frozen. It is designed as a machine insertion port, and the insertion tube of the JT refrigerator is inserted into this insertion port.

[0007]

However, in the above-mentioned conventional plug-in structure, there is a gap between the dewar refrigerator insertion port and the refrigerator insertion pipe, and convection of helium gas occurs in this gap. Due to the convection of the gas, heat is introduced into the dewar, and the refrigerating capacity of the refrigerator is substantially reduced.

The present invention has been made in view of the above circumstances, and an object thereof is to attach a space between the refrigerator insertion opening of the dewar and the insertion portion of the refrigerator to the dewar of the refrigerator. It is intended to automatically seal the gas and reliably prevent heat from entering the dewar due to convection of the refrigerant gas in the gap, thereby preventing deterioration in the capacity of the refrigerator.

[0009]

In order to achieve the above object, in the inventions of claims 1 and 2, a plurality of concentric packings are provided in the gap between the dewar refrigerator insertion port and the refrigerator insertion part. It was decided to seal and to block the convection of gas by the closed space formed between the plurality of packings.

Specifically, according to the invention of claim 1, FIG.
As shown in FIG. 3, with respect to the dewar (1) which stores the cryogenic level liquefied refrigerant, the insertion part (30) is inserted into the refrigerator insertion port (5) opened in the wall of the dewar (1). The refrigerant gas attached and sucked in the dewar (1) is sucked into the refrigerant circuit and compressed by the compressor, and expanded by the expansion means (26) to be condensed and liquefied, and the liquefied refrigerant is deliquefied in the dewar (1). It is premised on a cryogenic refrigerator that has been returned to.

The dewar-side flange (31) projecting from the periphery of the refrigerator insertion opening (5) of the dewar (1).
And a refrigerator-side flange (34) projecting so as to face the dewar-side flange (31) at the time of insertion into the refrigerator insertion port (5) on the outer periphery of the refrigerator insertion portion (30).

Further, one of the flanges (31) and (34) on the dewar side or the refrigerator side is the other flange (3).
4), a plurality of concentric packing receiving portions (33), (33), ... Are provided in a stepped manner on the surface facing the (31), while the other flange (34), (31) is provided with one flange ( Three
1), a plurality of concentric packing mounting portions (36), (36), ... On the surface facing the (34), the packing receiving portion (3).
3), (33), ... In correspondence with the packing receiving portions (33), (33) ,.

Further, the packing mounting portion (36),
A plurality of packings (3) with different diameters (3)
7), (37), ... are mounted, and the insertion part (30) of the refrigerator is attached.
When the packing is inserted into the refrigerator insertion opening (5) of the dewar (1), each packing (37) is squeezed between the packing receiving part (33) and the packing mounting part (36), and the packing (3
7), (37), ... Forming a closed space (40) between them.

On the other hand, according to the invention of claim 2, in the cryogenic refrigerator of the above premise, as shown in FIGS. 5 and 6, the same dewar side and refrigerator side flanges (3) as those of the invention of claim 1 are provided.
1) and (34) are provided, and these flanges (31) and (3
4) A plurality of concentric packing contact portions (42), (42) extending toward the other flange (34), (31) on the surface of the other flange (34), (31) facing the other. 、…
On the other hand, the packing abutting portions (42), (42), ... Are fitted on the surface of the other flange (34), (31) facing the one flange (31), (34). A plurality of concentric packing mounting grooves (43), (43), ... Are provided.

Then, a plurality of packings (3) having different diameters are respectively mounted in the packing mounting grooves (43).
7), (37), ... Are provided and the insertion part (30) of the refrigerator is inserted into the refrigerator insertion opening (5) of the dewar (1),
The packing (37) is clamped between the tip of the packing abutting portion (42) and the packing mounting groove (43), and the packing (3
7), (37), ... Forming a closed space (40) between them.

According to the third aspect of the present invention, a seal ring having a large heat shrinkage rate at a cryogenic temperature level is used, and by utilizing its characteristics, the gap between the Dewar refrigerator insertion port and the refrigerator insertion portion is automatically adjusted. I try to seal it.

That is, in the present invention, in the cryogenic refrigerator of the above premise, as shown in FIGS. 7 to 15, dewar-side and refrigerator-side flanges (31) and (34) are provided,
Refrigerator side flange (3) of Dewar side flange (31)
The first seal ring retainer (45) is provided on the surface facing the 4), while the second seal ring retainer (4) is provided on the surface facing the Dewar side flange (31) of the refrigerator side flange (34).
6) is provided on the first seal ring pressing portion (45) so as to face the refrigerator insertion direction.

Further, the second seal ring pressing portion (4
6) is equipped with a seal ring (48) made of a material having a heat shrinkage ratio at least at a cryogenic level higher than that of the dewar-side and refrigerator-side flanges (31) and (34),
The first or second seal ring pressing portion (45), (4
Refrigerator insertion port (5) for at least one of 6)
Toward the center of the first or second seal ring retainer (4
5) and (46) as guide surfaces which are displaced in a substantially tapered shape toward the other side, when the refrigerator insertion portion (30) is inserted into the refrigerator insertion opening (5) of the dewar (1), 1) The seal ring (48), which is cooled by the cold by the liquid refrigerant in the inside and has a smaller diameter relative to the dewar-side and refrigerator-side flanges (31) and (34), is guided by the guide surfaces to 2 Seal ring retainer (45), (4
6) and the dewar side and the refrigerator side flanges 31 and 34 are sealed.

[0019]

With the above construction, according to the first aspect of the invention, the insertion portion (3) for mounting the refrigerator on the dewar (1) is installed.
0) is inserted into the refrigerator insertion port (5), each packing (37) is pinched between the packing receiving part (33) and the packing mounting part (36). The packing receiving parts (33), (33), ... Are attached to one of the dewar-side or refrigerator-side flanges (31) and (34) and the other flange (3).
4) and (31) are formed concentrically and stepwise toward the side, while the packing mounting portions (36), (36), ... Have packing receiving portions (36) on the other flanges (34), (31). Three
3), (33), ... are formed in the shape of steps opposite to each other, so that when the packing (37) is clamped by the packing receiving part (33) and the packing mounting part (36), the packing (37) is , (37), ... A closed space (40) is formed. This closed space (40) allows the dewar (1)
The gap between the refrigerator insertion port (5) of the refrigerator and the insertion portion (30) of the refrigerator is closed and sealed, and the flow of the refrigerant gas in the gap space is shut off. Therefore, in the dewar (1). It is possible to effectively prevent heat from entering the refrigerator and improve the capacity of the refrigerator.

Further, in the invention of claim 2, when the insertion portion (30) of the refrigerator is inserted into the refrigerator insertion port (5) of the dewar (1), the dewar side is provided as in the invention of claim 1. Alternatively, the packing (37) in each packing mounting groove (43) on the other side of the refrigerator-side flanges (31), (34) may be replaced by the packing contact portion (42) of one of the flanges (34), (31). Is pinched between. The packing contact portions (42), (42), ...
1) and (34) are formed concentrically toward the sides, while the packing mounting grooves (43), (43), ... Correspond to the packing contact portions (42), (42) ,. Since the packing (37) is concentrically formed, when the packing (37) is clamped, the space (4) between the packings (37), (37) ,.
0) is formed, and the closed space (40) forms the refrigerator insertion opening (5) of the dewar (1) and the insertion portion (30) of the refrigerator.
It is possible to block the flow of the refrigerant gas by closing and sealing the gap between and.

According to the third aspect of the invention, the insertion portion (3
0) is inserted into the refrigerator insertion opening (5) of the dewar (1), the seal ring (48) mounted on the second seal ring retainer portion (46) of the refrigerator side flange (34) causes the dewar ( Although the liquid refrigerant in 1) is cooled by the cold and shrinks, the heat shrinkage rate of the seal ring (48) is larger than that of the Dewar-side and refrigerator-side flanges (31) and (34). ) Becomes smaller in diameter relative to both flanges (31) and (34) as it shrinks. Then, at least one of the seal ring pressing portions (45) and (46) of the flanges (31) and (34) is directed toward the center of the refrigerator insertion port (5).
Since it is a guide surface that is displaced in a taper shape toward the other of 5) and (46), the seal ring (48) having the small diameter is guided by the guide surface, so that both seal ring holding portions (45) are guided. ), (46), respectively, so that between the dewar-side and refrigerator-side flanges (31), (34), that is, between the refrigerator insertion port (5) of the dewar (1) and the refrigerator. The gap between the insertion portion (30) and the insertion portion (30) is closed and sealed, and the flow of the refrigerant gas is blocked.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIGS. 1 to 4 show Embodiment 1 of the present invention. In FIG. 3, (1) is a helium dewar that stores liquefied cryogenic level liquid helium, and is for keeping the superconducting coil of a superconducting magnet mounted on a linear motor car cooled below a critical temperature, though not shown. .. The dewar (1) is housed in a vacuum container (2), and a radiation shield (3) is disposed around the dewar (1) to prevent radiant heat from entering the dewar (1) from the outside.

An inner end of a horizontal pipe (4) made of stainless steel is fixed through one side wall of the dewar (1), and the horizontal pipe (4) penetrates the radiation shield (3) and extends to the outside thereof. , The outer end is fixed through the side wall of the vacuum container (2),
A refrigerator insertion port (5) is formed in the horizontal pipe (4) for communicating the inside of the dewar (1) with the outside of the vacuum container (2), and the JT refrigerator described later is inserted into this insertion port (5). (16)
Refrigerator (6) by inserting the insertion tube (30) of
Is attached to the dewar (1) or the vacuum container (2).

(6) is a cryogenic refrigerator which is detachably attached to the helium dewar (1) or the vacuum container (2). The refrigerator (6) removes the helium gas evaporated in the dewar (1). The liquid helium is sucked into the helium circuit, compressed and expanded to be condensed and liquefied, and the liquid helium is returned to the dewar (1).

That is, the refrigerator (6) is composed of a refrigerator in which a pre-cooling refrigerator (7) and a JT refrigerator (16) are combined as shown in FIG. The pre-cooling refrigerator (7) is composed of a G-M (Gifford-McMahon) cycle refrigerator, and uses helium gas to pre-cool the helium gas (refrigerant gas) in the J-T refrigerator (16). Compress and expand. This refrigerator (7) comprises a pre-cooling compressor (not shown) and an expander (8) connected in a closed circuit. The expander (8) includes a closed cylindrical case (9),
It has a cylinder (10) of large and small two-stage structure connected to the case (9). The case (9) includes a high pressure gas inlet (11) connected to the discharge side of the precooling compressor,
A low pressure gas outlet (12) connected to the suction side is opened. On the other hand, the large diameter part (10a) of the cylinder (10)
The tip of the first heat station (13) is cooled and maintained at a predetermined temperature level, and the tip of the small diameter portion (10b) is cooled and maintained at a temperature level lower than that of the first heat station (13). 2 heat stations (1
4), respectively. Although not shown here, a free-type displacer (replacer) for reciprocating the expansion space is formed in the cylinder (10) at positions corresponding to the heat stations (13) and (14). It is possible to be inserted. On the other hand, in the case (9), a rotary valve that opens and closes each time it rotates and a valve motor that drives the rotary valve are housed. The rotary valve allows the helium gas flowing from the high pressure gas inlet (11) to flow into the cylinder (1).
The helium gas supplied to each expansion space in 0) or expanded in each expansion space is switched to be discharged from the low pressure gas outlet (12). Then, by opening and closing this rotary valve, the high-pressure helium gas is expanded by Simon in each expansion space in the cylinder (10), and a temperature drop due to the expansion causes a cryogenic level of cold to be generated. It is held by the first and second heat stations (13) and (14). That is, in the pre-cooling refrigerator (7), the high pressure helium gas discharged from the compressor is supplied to the expander (8), and the adiabatic expansion in the expander (8) causes heat stations (13) and (14). The pre-coolers (22) and (24) of the J-T refrigerator (16), which will be described later, are pre-cooled and the expanded low-pressure helium gas is returned to the compressor and re-compressed. ing.

On the other hand, the JT refrigerator (16) is a refrigerator that compresses and expands helium gas in order to condense and liquefy helium gas due to generation of cold at 4K level, and compresses helium gas. A compressor (not shown) and an expander (17) for expanding the compressed helium gas by Joule-Thomson are provided, and the helium circuit is opened and opened in the dewar (1). The expander (17) is the first to third JT heat exchangers (18) to
It has (20). Each J-T heat exchanger (18)
(20) is for mutually exchanging heat between the helium gases passing through the primary side and the secondary side, and the primary side of the first JT heat exchanger (18) is the discharge side of the JT compressor. It is connected. In addition, the first and second J-T heat exchangers (1
The primary sides 8) and (19) are arranged on the outer periphery of the first heat station (13) of the adsorber (21) for removing contamination and the expander (8) of the pre-cooling refrigerator (7). It is connected via a first precooler (22). Similarly, the second and third J-T heat exchangers (19),
The respective primary sides of (20) are connected to each other via an adsorber (23) and a second precooler (24) arranged on the outer periphery of the second heat station (14) of the expander (8). Further, the primary side of the third J-T heat exchanger (20) is connected to the J-T valve (26) via the adsorber (25).
This J-T valve (26) expands high-pressure helium gas by Joule-Thomson, and its opening is adjusted by the operating rod (26a). The J-T valve (26) is connected to a cooler (27), a liquid helium discharge pipe (28) having an open end is connected to the cooler (27), and the dewar () of the refrigerator (6) is connected to the cooler (27). When attached to 1), this J
The liquid helium discharge pipe (28) of the -T refrigerator (16) is inserted from the refrigerator insertion port (5) so as to face the dewar (1).

A helium gas suction pipe (29) having an open tip is connected to the secondary side of the third JT heat exchanger (20). This helium gas suction pipe (29) is
The dewar (1) is arranged in parallel with the liquid helium discharge pipe (28), and is the same as the liquid helium discharge pipe (28) when the refrigerator (6) is attached to the dewar (1).
It is inserted from the refrigerator insertion port (5) so as to face the inside. And the helium gas suction pipe (29) is the third and second J
-T heat exchangers (20), (19) through each secondary side to the first
It is connected to the secondary side of the J-T heat exchanger (18),
The secondary side of the -T heat exchanger (18) is connected to the suction side of the JT compressor.

Therefore, in the JT refrigerator (16), when the dewar (1) is mounted, a part of the helium circuit is formed in the space inside the dewar (1), and the evaporated helium gas in the dewar (1) is formed. Is sucked from the helium gas suction pipe (29), and this is sucked into the third to first JT heat exchangers (20) to (1
It is compressed by a JT compressor through each secondary side of 8), and the compressed high pressure helium gas is expanded by an expander (17).
To the first to third JTs of the expander (17).
In the heat exchangers (18) to (20), heat is exchanged with the low temperature and low pressure helium gas reaching the compressor side, and
In the first and second precoolers (22) and (24), the first and second heat stations (13) of the expander (8),
After cooling at (14), the JT valve (26)
Thomson expansion is performed to form 4K liquid helium by the cooler (27), and this liquid helium is discharged from the liquid helium discharge pipe (28) into the dewar (1) and returned.

As shown in FIGS. 1 and 2, at the end portion (periphery of the refrigerator insertion port (5)) corresponding to the inside of the dewar (1) in the horizontal pipe (4) communicating the inside and outside of the dewar (1). Is provided with a dewar side flange (31) protruding inward in the radial direction of the refrigerator insertion port (5).

On the other hand, the JT refrigerator (16) is provided with an insertion pipe (30) for holding the liquid helium discharge pipe (28) and the helium gas suction pipe (29) in a juxtaposed state. The pipe (30) can be inserted into the refrigerator insertion port (5) in the horizontal pipe (4) of the dewar (1), and at the time of insertion, the tip of the insertion pipe (30) has the dewar side flange ( 31) It is adapted to be inserted into the opening (31a) at the inner end with a slight gap. Insertion tube (3
0) on the outer circumference of the horizontal pipe (4) refrigerator insertion port (5)
A refrigerator-side flange (34) (packing holding member) made of stainless steel that can be inserted into the front side of the refrigerator is provided so as to face the dewar-side flange (31) in the insertion direction. The flange (34) has a plurality of mounting bolts (39) attached to a mounting flange (38) having the same diameter as the refrigerator-side flange (34) integrally provided on the outer periphery of the insertion tube (30) at the back surface (outer surface of the dewar). ), (39), ...
It is attached and fixed via.

Then, the dewar side flange (31)
Of the step (32), (3) having different diameters on the surface (outer surface of the Dewar) facing the refrigerator-side flange (34).
2), ... are formed concentrically and toward the inside of the dewar toward the center of the insertion port (5), and each step (3
The outer surface of the dewar of 2) is a concentric annular packing receiving part (3
3). That is, the dewar-side flange (31) has three concentric packing receiving portions (33),
(33), ... Are formed in steps.

On the other hand, on the surface of the refrigerator-side flange (34) facing the dewar-side flange (31) (the inner surface of the dewar), three step portions (35), (35), ... With different diameters are concentrically formed. In addition, the dimension from the rear surface of the insertion tube (30) increases toward the center of the insertion tube (30), and the dewar side flange (31) corresponds to the steps (32), (32), ... The inner surface of the dewar of each step (35) is a concentric annular packing mounting portion (36). That is, three concentric packing mounting parts (36), (36), ... Are provided on the refrigerator side flange (34) and the packing receiving part (3) of the dewar side flange (31).
3), (33), ..., And are formed in a step shape in the opposite direction to the packing receiving portions (33), (33) ,.

A thin annular packing (37) made of indium, metal paste or the like is attached to each packing mounting portion (36) of the refrigerator side flange (34).
As shown in FIG. 1, when the insertion pipe (30) of the JT refrigerator (16) is inserted into the refrigerator insertion port (5) of the dewar (1), the refrigerator side flange ( Three
The packing (37) of 4) is clamped between the packing mounting portion (36) and the packing receiving portion (33) of the dewar side flange (31), and the packing (37), (37), ... It is configured to form one closed space (40), (40).

Next, the operation of the above embodiment will be described. When the refrigerator (6) that has been removed for inspection or repair is attached to the vacuum container (2) or the dewar (1) for operation, as shown in FIG. 1, the JT refrigerator (16) is inserted. The pipe (30) is inserted into the refrigerator insertion port (5) in the horizontal pipe (4) opening to the side wall of the vacuum container (2), and the helium gas suction pipe (29) and the inside of the insertion pipe (30) are inserted. Place the liquid helium discharge pipe (28) into the dewar (1),
The refrigerator (6) is operated in that state. In the operating state of the refrigerator (6), the high-pressure helium gas supplied from the compressor in the precooling refrigerator (7) expands in each expansion space of the expander (8), and the temperature drop accompanying the expansion of this gas. The first heat station (1
3) is cooled to a predetermined temperature level, and the second heat station (14) is cooled to a temperature level lower than that of the first heat station (13).

On the other hand, at the same time, the JT refrigerator (1
In 6), the high-pressure helium gas discharged from the compressor enters the primary side of the first JT heat exchanger (18), where it is heat-exchanged with the low-pressure helium gas on the secondary side reaching the compressor side. It is cooled from room temperature to about 50K, and then enters the first precooler (22) around the first heat station (13) of the expander (8) and is further cooled. The cooled gas enters the primary side of the second J-T heat exchanger (19) and is cooled to about 15K by heat exchange with the low pressure helium gas on the secondary side, and then expanded (8 2) enters the second precooler (24) around the second heat station (14) and is further cooled. Thereafter, the gas enters the primary side of the third J-T heat exchanger (20) and is cooled to about 5K by heat exchange with the low-pressure helium gas on the secondary side, and then J-
To the T valve (26). In this JT valve (26), high-pressure helium gas was squeezed and expanded by Joule-Thomson to 4K.
The liquid state helium is supplied to the cooler (27). Since the liquid helium discharge pipe (28) is connected to the cooler (27), the liquefied helium is discharged into the dewar (1) through the liquid helium discharge pipe (28). The liquid helium in the helium dewar (1) cools and holds the superconducting coil in the linear motor car below the critical temperature.

On the other hand, the low temperature and low pressure helium gas evaporated in the dewar (1) is the above helium gas suction pipe (29).
Sucked from the third to the first J-T heat exchanger (20)
After cooling the high-pressure helium gas on the primary side through each secondary side of (18), it is sucked into the J-T compressor and compressed, and then the Joule at the J-T valve (26) of the expander. -It is liquefied again by Thomson expansion and is returned to the inside of Dewar (1). As a result, a predetermined amount or more of liquid helium is stored in the dewar (1), and the superconducting coil is cooled stably.

At this time, when the insertion pipe (30) of the JT refrigerator (16) is inserted into the refrigerator insertion port (5) in the horizontal pipe (4) of the dewar (1), the insertion pipe ( The tip of 30) is the opening (31) at the inner end of the dewar side flange (31).
a) and the refrigerator-side flange (34) on the outer circumference of the insertion pipe (30) are inserted into the inner surface of the horizontal pipe (4) with a slight gap, and each packing is attached to the refrigerator-side flange (34). The packing (37) on the part (36) is the packing receiving part (3) of the dewar side flange (31).
It is crimped to 3) and is pinched between the packing receiving part (33) and the packing mounting part (36). Then, the three packing receiving portions (33) of the dewar side flange (31),
The (33), ... Are formed concentrically and stepwise toward the refrigerator side flange (34) side, while the packing mounting parts (36), (36), ... Of the refrigerator side flange (34) are formed.
Are formed in the shape of steps opposite to the packing receiving portions (33), (33), ..., Therefore, when the packings (37) are in a pinched state, the packings (37), (37), ... To 2
Two closed spaces (40), (40) are formed. These closed spaces (40) and (40) securely close and seal the gap between the refrigerator insertion port (5) of the dewar (1) and the insertion pipe (30) of the JT refrigerator (16). , It is possible to block the convection of the helium gas in the dewar (1) to the outside through the interstitial space, effectively preventing the heat from entering the dewar (1) from the outside, and thus the refrigerator. The ability of (6) can be improved.

In this embodiment, each packing (37)
The refrigerator-side flange (34) is attached to the refrigerator-side flange (34), and the refrigerator-side flange (34) is provided with a packing receiving portion, while the dewar-side flange (31) is provided with a packing attaching portion. ) Dewar side flange (3
It may be attached to 1). But in that case,
Since the packing (37) may be constantly cooled and held by the liquid helium in the dewar (1) and deteriorated, in order to avoid this, as in the first embodiment, the packing (3) is used.
7) is preferably attached to the refrigerator side flange (34). Further, the number of packings (37) may be a plurality other than three.

(Embodiment 2) FIGS. 5 and 6 show Embodiment 2 of the present invention (in the following embodiments, the same parts as those in FIGS. However, the mounting portion of the packing (37) is a groove.

That is, in this embodiment, the horizontal pipe (4)
Of the dewar-side flange (31) facing the refrigerator-side flange (34) (the outer surface of the dewar) are two thin cylindrical packing contact portions (42) having different diameters,
(42) is formed concentrically, and both packing abutting portions (42), (42) protrude toward the outside of the dewar by the same length.

On the other hand, the insertion tube (3) of the JT refrigerator (16)
0) Face of the refrigerator-side flange (34) attached to the outer periphery to the dewar-side flange (31) (inside surface of dewar)
Two annular packing mounting grooves (43) and (43) having different diameters, into which the packing abutting portions (42) and (42) of the dewar side flange (31) can be fitted, are formed concentrically. The depth of each packing mounting groove (43) is slightly shorter than the protruding length of the packing contact portion (42), and the groove width has a gap on both sides when the packing contact portion (42) is inserted. The packing contact portion (42) is wider than the thickness of the contact portion (42).

Then, packings (37) and (43) are provided on the bottoms of the two packing mounting grooves (43) and (43) of the refrigerator side flange (34) and on the inner peripheral portion of the tip end surface of the refrigerator side flange (34), respectively. (37), ... are attached,
As shown in FIG. 5, the insertion tube (3) of the JT refrigerator (16)
0) is inserted into the refrigerator insertion opening (5) of the dewar (1), the packing (37) in each packing mounting groove (43) of the refrigerator side flange (34) is attached to the packing of the dewar side flange (31). The packing (3) at the tip of the contact portion (42) and at the inner peripheral portion of the tip surface of the refrigerator side flange (34).
7) is crimped to the inner peripheral portion of the dewar outer surface of the dewar side flange (31) to clamp each packing (37), and two closed spaces (40) are provided between these packings (37), (37), .... , (40) are formed. Other configurations are the same as those in the first embodiment.

Therefore, in this embodiment, when the insertion pipe (30) of the JT refrigerator (16) is inserted into the refrigerator insertion port (5) in the horizontal pipe (4) of the dewar (1), As shown in FIG. 5, each packing contact portion (42) of the Dewar side flange (31) of the horizontal pipe (4) is inserted into each packing mounting groove (43) of the refrigerator side flange (34) on the outer circumference of the insertion pipe (30). ) Are inserted and the packings (37) in the packing mounting grooves (43) are respectively attached to the packing contact portions (42).
And the packing (37) on the inner peripheral surface of the end surface of the refrigerator-side flange (34) is attached to the dewar-side flange (31).
Each packing (37) is pinched by being crimped to the inner peripheral portion of the outer surface of the dewar. The packing contact portion (42) of the dewar side flange (31) is formed concentrically toward the outer side of the dewar, while the packing mounting grooves (43) of the refrigerator side flange (34) are in contact with the packing. Since they are formed concentrically corresponding to the portion (42), the packing (3
7), (37), ... Between the two closed spaces (40), (4)
0) is formed. Therefore, this closed space (40),
(40) can block and seal the gap between the refrigerator insertion port (5) of the dewar (1) and the insertion pipe (30) of the JT refrigerator (16) to interrupt the flow of helium gas. it can.

Also in this embodiment, the packing abutment portion is provided on the refrigerator side flange (34) and the packing mounting groove is formed on the dewar side flange (31) to mount the packing (37). The side may be the dewar side flange (31), and the number of packings (37) is three.
Not limited to one.

(Embodiment 3) FIGS. 7 to 9 show Embodiment 3 in which the seal structure and the seal member are changed.
That is, in this embodiment, the first seal ring pressing portion (45) is formed on the outer side of the dewar of the dewar side flange (31) of the horizontal pipe (4). The seal ring pressing portion (45) is a tapered guide surface that is tapered toward the outside of the dewar toward the center of the refrigerator insertion port (5).

On the other hand, the insertion tube (3) of the JT refrigerator (16)
0) A second seal ring retainer portion (46) is formed on the inner surface of the dewar of the refrigerator side flange (34) attached to the outer periphery, and the seal ring retainer portion (46) is the first seal ring retainer portion (46). Contrary to 45), it is a tapered guide surface that is inclined toward the inside of the dewar toward the center of the refrigerator insertion port (5), and the inner end of the second seal ring pressing portion (46) is inside the flange. It is continued to the step portion (47) having a diameter slightly smaller than the opening at the end. That is, in this embodiment, the first and second seal ring pressing portions (45), (4
Both 6) are guide surfaces that are inclined in a taper shape toward the other seal ring pressing portions (46) and (45) facing toward the center of the refrigerator insertion port (5).

Further, a seal ring (48) consisting of an O-ring is held in engagement with the second seal ring pressing portion (46) or step (47) of the refrigerator side flange (34). This seal ring (48) is made of Teflon (registered trademark) having a heat shrinkage ratio at a cryogenic level higher than that of the Dewar-side and refrigerator-side flanges (31) and (34) made of the above-mentioned stainless steel. As shown by the solid line, at room temperature, the seal ring (48) has the second seal ring retainer (46) (or the first seal ring retainer (4).
5)) Radiator midpoint slightly more than refrigerator insertion port (5)
The diameter is set so as to contact the center side of the.

When the insertion pipe (30) of the JT refrigerator (16) is inserted into the refrigerator insertion port (5) of the dewar (1), the seal ring (48) is placed in the liquid inside the dewar (1). It is cooled by cooling with helium to have a smaller diameter relative to the dewar-side and refrigerator-side flanges (31) and (34), and the seal ring (48) having this smaller diameter is first
And the guide surfaces of the second seal ring retainers (45), (46) guide the seal ring retainers (45),
The dewar side and the refrigerator side flanges (31) and (34) are brought into close contact with each other to seal the gap between them.

Therefore, in this embodiment, when the insertion tube (30) of the JT refrigerator (16) is inserted into the refrigerator insertion port (5) of the dewar (1), the state immediately after the insertion is as shown in FIG. As shown by the solid line, the center of the seal ring (48) is located at the point O, and the seal ring holding portion (45) of the dewar-side and refrigerator-side flanges (31) and (34) is
It is sandwiched between (46). Then, after this, the seal ring (48) is cooled by the liquid helium in the dewar (1) so that the dewar side and the refrigerator side flange (3
1) and (34) cool and shrink, but the heat shrinkage rate of this seal ring (48) is both flanges (31),
Since it is larger than (34), the center of the seal ring (48) moves from the O point to the O'point as the seal shrinks, and the radius of the dimension (d) is relatively increased with respect to the flanges (31) and (34). It has a small diameter. At that time, the both flanges (31),
Both seal ring retainers (45) and (46) of (34) are tapered toward the center of the refrigerator insertion port (5) toward the seal ring retainers (45) and (46) of the other side. Since the seal ring (48) is inclined to, the seal ring (48) is guided by the guide surface as much as the reduced diameter, as shown by the phantom line in FIG. , (46) respectively, so that the dewar-side and refrigerator-side flanges (31), (3
4), that is, the refrigerator insertion opening (5) of the dewar (1)
And the insertion pipe (30) of the JT refrigerator (16) are closed and sealed to block the flow of helium gas.
Therefore, also in this embodiment, it is possible to obtain the same effects as those of the above embodiments.

(Fourth Embodiment) FIGS. 10 to 12 show a fourth embodiment. In this embodiment, only the first seal ring retaining portion (45) of the refrigerator side flange (34) is the same as that of the third embodiment. And the first seal ring pressing portion (45) of the dewar side flange (31) is a flat surface extending in a direction orthogonal to the center line of the refrigerator insertion port (5). Has been done. Others are the same as in the third embodiment.

Therefore, also in this embodiment, when the seal ring (48) is cooled and contracted by the liquid helium in the dewar (1), the diameter becomes relatively small with respect to the flanges (31) and (34). This seal ring (48)
As shown by the phantom line in FIG. 10, due to the smaller diameter, the first seal ring pressing portion (45) guides the seal ring pressing portions (45) and (46), respectively. Side and refrigerator side flange (31),
The gap between (34) can be closed and sealed to block the flow of helium gas.

(Fifth Embodiment) FIGS. 13 to 15 show a fifth embodiment. In the third embodiment, the guide surfaces of the first and second seal ring pressing portions (45) and (46) are linear in cross section. In contrast to the above-described inclination, in this embodiment, the cross section is displaced so as to have an arc shape. Therefore, also in this embodiment, the same operational effect as that of the third embodiment can be obtained.

In each of the above embodiments, the coil of the superconducting magnet of the linear motor car is cooled.
The present invention can be applied to any structure as long as the refrigerator is integrally provided in the dewar for storing the liquid refrigerant.

[0055]

As described above, according to the first aspect of the invention, the dewar storing the cryogenic liquid refrigerant is
In a structure in which a cryogenic refrigerator that compresses and expands the refrigerant gas evaporated in the dewar to condense and liquefy in the refrigerant circuit is detachably mounted, a dewar-side flange is projected on the periphery of the dewar refrigerator inlet and A refrigerator-side flange is projected on the outer periphery of the insertion part of the machine, and a plurality of concentric and step-shaped packing receiving parts are provided on the surface of one of the two flanges facing the other flange, while the other flange is provided with the packing receiving part. When the insert part of the refrigerator is inserted into the Dewar refrigerator insertion port, the packing of each packing attachment part is attached to the packing receiving part. It was squeezed between and to form a closed space between the packings. In addition, claim 2
In the invention of claim 1, a plurality of concentric packing contact portions are provided on one of the dewar side or the refrigerator side flange, while the other flange is provided with a plurality of concentric packing mounting grooves into which the packing contact portions are fitted. When the insert part of the refrigerator is inserted into the refrigerator insert opening of the dewar, the packing is pressed by the packing contact grooves of the dewar side flange between the packing mounting grooves of the refrigerator side flange. A closed space was formed between them. Furthermore, in the invention of claim 3, the first dewar side flange is provided with the first seal ring retainer, while the refrigerator side flange is provided with the second seal ring retainer opposed to the first seal ring retainer in the insertion direction. A seal ring having a heat shrinkage ratio at least at a cryogenic level larger than that of both flanges is attached to the second seal ring retainer, and at least one of the seal ring retainers is connected to the other side of the refrigerator insertion port toward the center. When the insertion part of the refrigerator is inserted into the Dewar refrigerator insertion port, the seal ring that is cooled by the liquid refrigerant and has a relatively small diameter relative to both flanges is used. By the guide of the guide surface, the seal ring pressing portions are brought into close contact with each other to seal the gap between the flanges. Therefore, according to these inventions, it is possible to seal the gap between the dewar refrigerator insertion port and the refrigerator insertion portion, and to block the flow of the refrigerant gas in the gap space,
Therefore, it is possible to effectively prevent heat from entering the dewar and improve the capacity of the refrigerator.

[Brief description of drawings]

FIG. 1 is a sectional view of essential parts showing a state in which a refrigerator is completely inserted in a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts showing a removed state of the refrigerator in the first embodiment.

FIG. 3 is a cross-sectional view showing a structure for mounting a refrigerator on a dewar.

FIG. 4 is a refrigerant circuit diagram showing a circuit configuration of a cryogenic refrigerator.

FIG. 5 is a view corresponding to FIG. 1 in the second embodiment.

FIG. 6 is a view corresponding to FIG. 2 in the second embodiment.

FIG. 7 is an enlarged cross-sectional view of a seal portion according to a third embodiment.

FIG. 8 is a view corresponding to FIG. 1 in the third embodiment.

9 is a view corresponding to FIG. 2 in Embodiment 3. FIG.

FIG. 10 is an enlarged cross-sectional view of a seal portion according to the fourth embodiment.

FIG. 11 is a view corresponding to FIG. 1 in Example 4.

FIG. 12 is a view corresponding to FIG. 2 in the fourth embodiment.

FIG. 13 is an enlarged cross-sectional view of a seal portion according to the fifth embodiment.

14 is a view corresponding to FIG. 1 in Example 5. FIG.

FIG. 15 is a view corresponding to FIG. 2 in the fifth embodiment.

[Explanation of symbols]

 (1) Helium Dewar (4) Horizontal pipe (5) Refrigerator insertion port (6) Refrigerator (7) Precooling refrigerator (16) JT refrigerator (26) JT valve (expansion means) (28) Liquid helium discharge pipe (29) Helium gas suction pipe (30) Insert pipe (refrigerator insertion part) (31) Dewar side flange (33) Packing receiving part (34) Refrigerator side flange (36) Packing installation part (37) ) Packing (40) Closed space (42) Packing contact part (43) Packing mounting groove (45) First seal ring retainer (46) Second seal ring retainer (48) Seal ring

Claims (3)

[Claims] 1. A dewar (1) for storing a cryogenic level liquefied refrigerant, and an insertion part (30) for the dewar (1).
The refrigerant gas inserted into the refrigerator insertion opening (5) opened in the wall portion is attached, the refrigerant gas evaporated in the dewar (1) is sucked into the refrigerant circuit and compressed by the compressor, and the expansion means (2
In a cryogenic refrigerator in which it is expanded in 6) to be condensed and liquefied, and the liquefied refrigerant is returned to the inside of the dewar (1), the dewar projecting at the periphery of the refrigerator insertion port (5) of the dewar (1). A side flange (31) and a refrigerator-side flange that is provided on the outer periphery of the insertion portion (30) of the refrigerator so as to face the dewar-side flange (31) when the refrigerator is inserted into the refrigerator insertion port (5). (34) and the flanges (31), (3) on the dewar side or the refrigerator side.
4) a plurality of concentric packing receiving parts (33), (3) are provided on the surface facing one of the other flanges (34), (31).
3), ... Are provided in steps, while a plurality of concentric packing mounting portions (36) are provided on the surface of the other flange (34), (31) facing the one flange (31), (34). , (36), ... Are provided in a step shape corresponding to the packing receiving parts (33), (33), ... And in a step direction opposite to the packing receiving parts (33), (33) ,. A plurality of packings (37), (37), ... having different diameters are mounted on the packing mounting parts (36), (36), ..., and the insertion part (30) of the refrigerator is frozen by the dewar (1). When inserted into the machine insertion port (5), each packing (37) is squeezed between the packing receiving part (33) and the packing mounting part (36), and between the packings (37), (37), ... Cryogenic cooling characterized in that it is configured to form a closed space (40) Machine of the mounting device. 2. A dewar (1) for storing a cryogenic level liquefied refrigerant, and an insertion part (30) for the dewar (1).
The refrigerant gas inserted into the refrigerator insertion opening (5) opened in the wall portion is attached, the refrigerant gas evaporated in the dewar (1) is sucked into the refrigerant circuit and compressed by the compressor, and the expansion means (2
In a cryogenic refrigerator in which it is expanded in 6) to be condensed and liquefied, and the liquefied refrigerant is returned to the inside of the dewar (1), the dewar projecting at the periphery of the refrigerator insertion port (5) of the dewar (1). A side flange (31) and a refrigerator side flange (34) projecting from the outer periphery of the insertion portion (30) of the refrigerator facing the dewar side flange (31) are provided, and the dewar side or the refrigerator is provided. Side flanges (31), (3
4) a plurality of concentric packing abutting portions (42), (42) extending toward the other flange (34), (31) on the surface facing the other flange (34), (31). ),
, And the packing abutting portions (42), (42), ... Are fitted on the surfaces of the other flanges (34), (31) facing the one flange (31), (34). A plurality of concentric packing mounting grooves (43), (43), ... Are provided, and a plurality of packings (37), (37) having different diameters are provided in the packing mounting grooves (43), (43) ,. ), ... Are attached, and when the insertion portion (30) of the refrigerator is inserted into the refrigerator insertion opening (5) of the dewar (1), each packing (37) is connected to the tip of the packing contact portion (42). A cryogenic refrigerator characterized in that it is configured to form a closed space (40) between packings (37), (37), ... by being pinched with the packing mounting groove (43). Mounting device. 3. The dewar (1) is provided with an insertion part (30) for the dewar (1) which stores a cryogenic level liquefied refrigerant.
The refrigerant gas inserted into the refrigerator insertion opening (5) opened in the wall portion is attached, the refrigerant gas evaporated in the dewar (1) is sucked into the refrigerant circuit and compressed by the compressor, and the expansion means (2
In a cryogenic refrigerator in which it is expanded in 6) to be condensed and liquefied, and the liquefied refrigerant is returned to the inside of the dewar (1), the dewar projecting at the periphery of the refrigerator insertion port (5) of the dewar (1). A side flange (31) and a refrigerator side flange (34) projecting from the outer periphery of the insertion portion (30) of the refrigerator facing the dewar side flange (31) are provided, and the dewar side flange (31) ) On the side facing the refrigerator-side flange (34), the first seal ring pressing portion (4
5) is provided while the dewar side flange (3) of the refrigerator side flange (34) is provided.
A second seal ring retainer (46) is provided on the surface facing the first seal member (1) so as to face the first seal ring retainer (45) in the refrigerator insertion direction, and the second seal ring retainer (46) is provided. ) Is equipped with a seal ring (48) made of a material having a heat shrinkage rate at least at a cryogenic level higher than that of the dewar-side and refrigerator-side flanges (31), (34), and the first or second Seal ring retainer (45), (4
At least one of 6) faces the center of the refrigerator insertion port (5) and the other two seal ring retainers (46), (4).
5) It is a guide surface that is displaced in a substantially tapered shape toward the inside of the dewar (1) when the insertion portion (30) of the refrigerator is inserted into the refrigerator insertion opening (5) of the dewar (1). The first and second seal rings (48), which have been made smaller in diameter than the dewar-side and refrigerator-side flanges (31) and (34) by being cooled by the cold of the liquid refrigerant, are guided by the guide surface.
The seal ring retainers (45) and (46) are closely attached to the dewar side and refrigerator side flanges (31) and (3), respectively.
4) A cryogenic refrigerator mounting device, characterized in that it is configured to seal a gap between them.