JP2018195771A - Cryogenic device - Google Patents

Abstract

To provide a novel cryogenic device capable of suppressing intrusion heat to a low level while avoiding enlarging an entire device.SOLUTION: A space around a small refrigerator 150 is partitioned into a first gap S1 and a second gap S2 by a partition cover 170. A vaporized gas generated in an inner container 110 is exhausted through the second gap S2. As a result, sensible heat of a vaporized gas flowing through the second gap S2 can efficiently cool a neck tube 140, a conductive wire C, etc., which is one of the paths of intrusion heat, so that it is possible to significantly reduce heat entering the inner container 110 while avoiding enlarging the entire device.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cryogenic apparatus for cooling a superconducting device to a cryogenic state using a cryogen such as liquid helium, and more particularly to a cryogenic apparatus incorporating a cryogen recondensing means.

  Conventionally, in a cryogenic apparatus that is used by cooling a superconducting magnet for MRI or the like with a cryogen such as liquid helium, it is common to incorporate a small refrigerator for recondensing the vaporized cryogen. As a cryogenic apparatus incorporating such a small refrigerator, for example, as shown in Patent Document 1 below, a structure in which a refrigerator head is fitted to an opening (neck tube) communicating with a container, As shown in Patent Document 2, a structure in which a small refrigerator is housed in an independent chamber has been proposed.

JP 2009-162480 A US Patent US9234361B2

  By the way, in the structure as shown in Patent Document 1, the neck tube for mounting the small refrigerator has a large diameter, and when the number of superconducting sensors increases, the number of conductors for connecting to it increases, so the neck tube And intrusion heat tends to increase through a conductor or the like wired therein. On the other hand, in the structure of Patent Document 2, although the neck tube can be reduced in diameter, a space for installing the refrigerator is required separately, so that the entire apparatus tends to be enlarged.

  Therefore, the present invention has been devised to solve these problems, and an object of the present invention is to provide a novel cryogenic apparatus that can keep intrusion heat low while avoiding an increase in size of the entire apparatus. There is.

  In order to solve the above-mentioned problem, a first invention is a cryogenic apparatus comprising an inner container for accommodating a cooled object together with a cryogen and an outer container for accommodating the inner container. A neck tube passing through the neck tube, and a refrigerator is fitted in the neck tube, and a partition cover is provided so as to surround the refrigerator in the neck tube, and is formed inside the partition cover. The gas supply port is connected to the first gap, the gas discharge port is formed in the second gap formed outside the partition cover, and the gas discharge port and the gas supply port are connected by a gas circulation line. This is a cryogenic device characterized by that.

  According to such a configuration, the space around the refrigerator is partitioned by the partition cover into the first inner space and the second outer space, so that the gas in the gas circulation line passes from the gas supply port to the first inner space. Then, it is directly cooled by a refrigerator and recondensed (liquefied), and then supplied to the inner container. On the other hand, the vaporized gas generated in the inner container flows through the second gap outside the partition cover and exhausts from the gas discharge port to the gas circulation line. And since the neck tube which is one of the path | routes of the penetration | invasion heat can be efficiently cooled by the sensible heat of the vaporization gas which flows through this 2nd space | gap, the penetration | invasion heat | fever to an inner container is suppressed low, avoiding the enlargement of the whole apparatus. be able to.

  The second invention is a cryogenic apparatus comprising an inner container for accommodating a body to be cooled together with a cryogen and an outer container for accommodating the inner container, and forming a neck tube penetrating the outer container from the inner container At the same time, a refrigerator is fitted in the neck tube, a partition cover is provided so as to surround the refrigerator in the neck tube, and a communication hole is formed in the partition cover to The first gap formed on the inner side and the second gap formed on the outer side of the partition cover communicate with each other, and the opening end of the partition cover is closed with a lid member having a liquid passage. It is a cryogenic device.

  According to such a configuration, since the gap around the refrigerator is partitioned into the first inner gap and the second outer gap by the partition cover, the gas in the inner first gap is directly cooled by the refrigerator. After recondensing (liquefaction), it flows down to the inner container. Then, since the inside of the first gap inside the partition cover has a negative pressure, the vaporized gas generated in the inner container passes through the communication hole formed in the partition cover from the second gap outside the partition cover and enters the first gap. And a continuous gas flow in one direction is generated from the second gap toward the first gap. And since the neck tube which is one of the path | routes of the penetration | invasion heat can be efficiently cooled by the sensible heat of the vaporization gas which flows through this 2nd space | gap, the penetration | invasion heat | fever to an inner container is suppressed low, avoiding the enlargement of the whole apparatus. be able to.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the cryogenic apparatus is characterized in that a conductive wire connected to the object to be cooled and a pipe for supplying the cryogen are disposed in the second gap. . According to such a configuration, not only the neck tube which is one of the paths of intrusion heat by the sensible heat of the vaporized gas flowing through the second gap, but also the lead wire connected to the object to be cooled and the tube supplying the cryogen. It can be cooled efficiently.

  According to the present invention, the sensible heat of the vaporized gas flowing through the second gap can efficiently cool the neck tube, which is one of the paths of intrusion heat, the lead wire connected to the object to be cooled, the tube supplying the cryogen, and the like. Intrusion heat into the inner container can be significantly reduced while avoiding an increase in size of the entire apparatus.

It is sectional drawing which shows one Embodiment of the cryogenic apparatus 100 which concerns on this invention. It is the elements on larger scale which show the A section in FIG. It is sectional drawing which shows other embodiment of the cryogenic apparatus 100 which concerns on this invention. It is sectional drawing which shows other embodiment of the cryogenic apparatus 100 which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an embodiment of a cryogenic apparatus 100 according to the present invention. As shown in the figure, the cryogenic apparatus 100 includes a cylindrical inner container 110 that accommodates the object to be cooled 10 together with the cryogen 11, and a cylindrical inner container that accommodates the inner container 110 via the vacuum space 20 and the radiation shield 130. It has a double structure with the outer container 120.

  A circular opening 111 is formed in the center of the top plate of the inner container 110, and a cylindrical neck tube 140 is provided in the opening 111 so as to extend vertically upward therefrom. The upper end of the neck tube 140 passes through the top plate of the outer container 120, and the condenser 151 of the small refrigerator 150 is provided so as to fit inside the upper end opening.

  The small refrigerator 150 is a low-vibration refrigerator called a pulse tube, for example, and includes the condenser 151 located inside and the refrigerator head 152 exposed outside as described above. A compressor 154 is connected to the refrigerator head 152 via a plurality of gas pipes 153, and a refrigerant for the refrigerator is compressed and circulated by the compressor 154 to constitute a refrigeration cycle. In addition, the refrigerator currently marketed has a condensation capacity of about 1 W at helium temperature.

  The object to be cooled 10 accommodated in the inner container 110 is a superconducting magnetic sensor such as a SQUID (superconducting quantum interference device) that operates in an extremely low temperature state, and measures an extremely weak field generated from a living body. Can do. The cryogen 11 that cools the object to be cooled 10 is, for example, a cryogenic liquid such as liquid helium having an atmospheric pressure boiling point of 4.2K.

  FIG. 2 is an enlarged view showing a portion A in FIG. 1, and shows a detailed structure near the neck tube 140 extending from the inner container 110 to the outer container 120. As illustrated, the neck tube 140 has a cylindrical shape with both upper and lower ends opened, and is provided so as to connect between the opening 111 of the top plate of the inner container 110 and the top plate of the outer container 120. Further, a ring-shaped adapter 160 having a U-shaped cross section is provided on the upper end side of the neck tube 140, that is, on the top plate of the outer container 120 so as to surround the upper end opening of the neck tube 140. A donut disk-shaped refrigerator flange 161 is mounted on 160.

  Then, by inserting the condenser 151 side of the small refrigerator 150 through the opening of the refrigerator flange 161 and fixing the refrigerator head 152 side on the refrigerator flange 161, the condenser 151 is formed as shown in the figure. It is attached to fit within the neck tube 140.

  A cylindrical partition cover 170 is provided on the lower surface side of the refrigerator flange 161 so as to extend vertically downward therefrom. The partition cover 170 has an open lower end, an inner diameter larger than the outer diameter of the condenser 151, and a predetermined gap (first gap) between the condenser 151 and the surface of the condenser 151. It is provided so as to surround S1). In addition, the outer diameter of the partition cover 170 is smaller than the inner diameter of the neck tube 140, and an annular space (second space S 2) is formed between the partition cover 170 and the neck tube 140.

  A gas supply port 162 is formed in the refrigerator flange 161 and communicates with the first gap S1 inside the partition cover 170. On the other hand, a gas exhaust port 163 is formed in the adapter 160 to which the refrigerator flange 161 is attached, and communicates with the second gap S2 outside the partition cover 170. A gas circulation line L is connected to the gas discharge port 163 and the gas supply port 162 as shown in FIG.

  The gas circulation line L is provided with a circulation pump 30, a gas cylinder 31 having a valve 34, and a discharge pipe 32 having a valve 33. The circulation pump 30 causes the gas exhaust port 163 to enter the second gap S2. The vaporized gas is extracted and circulated so as to be supplied from the gas supply port 162 into the first gap S1. In the course of the gas circulation, a part of the gas can be discharged from the discharge pipe 32 as appropriate, or the gas can be replenished from the gas cylinder 31.

  As shown in FIG. 2, the adapter 160 to which the refrigerator flange 161 is attached is provided with a liquid supply port 164 in addition to the gas discharge port 163. A liquid supply pipe (not shown) is connected to the liquid supply port 164 so that the cryogen 11 such as liquid helium can be directly supplied into the inner container 110. A transfer tube insertion tube 165 is connected to the inside of the liquid supply port 164, and the transfer tube insertion tube 165 is disposed so as to pass through the second gap S2 downward.

  Further, in the second gap S2, a plurality of conductive wires C extending from the cooled object 10 such as a superconducting magnetic sensor disposed in the inner container 110 are wired so as to pass upward. It extends outside from an airtight drawer portion 180 formed between the adapter 160 and the outer container 120 and is connected to an external device (not shown).

  The adapter 160, the refrigerator flange 161, and the small refrigerator 150 are detachable from the outer container 120, and are secretly sealed against the outside air by an O-ring, packing, or the like during assembly. In addition, the inner container 110, the outer container 120, the neck tube 140, the partition cover 170, and the like are formed of a low heat conductive material such as glass fiber reinforced resin (FRP), and the amount of heat that enters through these can be kept low. ing.

  Next, the operation of the cryogenic apparatus 100 according to the present invention having such a configuration will be described. As shown in FIG. 1, the object to be cooled 10 such as a superconducting magnetic sensor disposed in the inner container 110 sufficiently exhibits its function by being cooled to a cryogenic state by a cryogen 11 such as liquid helium. However, in the inner container 110 in that state, the liquid cryogen 11 always evaporates due to intrusion heat from various paths, etc., and fills the inner container 110 as vaporized gas.

  As shown in FIG. 2, the vaporized gas in the inner container 110 tends to exit to the outside from the opening 111 formed in the top plate of the inner container 110. At this time, the first gap S <b> 1 partitioned by the partition cover 170 is used. Since the pressure is increased by the circulating gas that is sequentially supplied, it flows to the second gap S2 side, which is a low pressure outside, and passes through the second gap S2 to rise to the gas circulation line L from the gas discharge port 163. Discharged.

  The low-temperature vaporized gas thus generated in the inner container 110 continuously flows on the second gap S2 side, whereby the conducting wire C and the transfer tube insertion pipe 165 disposed in the second gap S2 and Since the neck tube 140 is effectively cooled by the sensible heat, it is possible to keep the amount of heat that conducts these and enters the inner container 110 side low.

  On the other hand, the gas discharged from the gas discharge port 163 to the gas circulation line L is supplied again from the gas supply port 162 into the first gap S1 inside the partition cover 170 by the pump 30 and is supplied to the condenser 151 of the small refrigerator 150. Since the liquid is forcibly cooled and recondensed (liquefied), becomes a liquid and falls (drops) into the inner container 110 and is reused as the cryogen 11, the cryogen 11 in the inner container 110 is not insufficient. .

  As described above, the cryogenic apparatus 100 according to the present invention partitions the gap around the condenser 151 of the small refrigerator 150 into the first gap S1 and the second gap S2 by the partition cover 170, and vaporizes generated in the inner container 110. Since the gas is exhausted through the outer second gap S2, the neck tube 140 and the conductor C, which are one of the paths of intrusion heat, can be efficiently cooled by the sensible heat of the vaporized gas flowing therethrough. it can. As a result, it is possible to significantly reduce the intrusion heat into the inner container 110 while avoiding an increase in the size of the entire apparatus.

  Next, FIG. 3 shows another embodiment of the cryogenic apparatus 100 according to the present invention. As shown in the figure, in the present embodiment, one or more communication holes 173 are formed on the upper end side of the partition cover 170 to communicate the first gap S1 and the second gap S2, and the opening end of the partition cover 170 is shown. The portion is closed with a funnel-shaped lid member 171 having a liquid passage 172, and the gas discharge port 163 and the gas supply port 162 are closed.

  With such a configuration, the vaporized gas generated in the inner container 110 cannot flow into the inside of the partition cover 170, that is, the first gap S1 because of the cover member 171, and all of the gas does not flow into the outer second gap. It flows to the S2 side, rises, passes through the communication hole 173 on the upper end side thereof, and flows into the first gap S1. As a result, the conductive wire C, the transfer tube insertion tube 165, and the neck tube 140 disposed in the second gap S2 are effectively cooled by the sensible heat of the vaporized gas, as in the above embodiment. The amount of heat that is conducted and enters the inner container 110 can be kept low.

  On the other hand, the vaporized gas that has flowed into the first gap S <b> 1 is forcibly cooled by the condenser 151, recondensed (liquefied), and dropped onto the lid member 171 as a liquid. Further, since the vaporized gas recondensing step causes the first void S1 to be in a negative pressure state than the second void S2, the vaporized gas in the second void S2 flows smoothly and continuously into the first void S1. become. Then, the liquid dropped on the lid member 171 falls into the inner container 110 from the liquid passage 172 at the center and is reused as the cryogen 11.

  As described above, even if one or more communication holes 173 are formed on the upper end side of the partition cover 170 and the opening end of the partition cover 170 is closed by the lid member 171 as in the above embodiment. By the sensible heat of the vaporized gas, the neck tube 140, the conductive wire C, etc., which are one of the paths of intrusion heat, can be efficiently cooled. As a result, not only can the overall size of the device be avoided, but the heat entering the inner container 110 can be significantly reduced, and the gas circulation line L can be eliminated, thereby simplifying the overall device. it can.

  The liquid passage 172 formed in the lid member 171 has a small diameter (narrow tube) as much as possible in order to maintain a state in which the inside of the liquid passage 172 is always filled with liquid (blocked) in order to prevent invading vaporized gas. However, if it is too small, the liquid may freeze inside and clog up due to impurities. Therefore, as shown in the figure, an electric heater 174 may be attached outside the liquid passage 172, and the liquid passage 172 may be appropriately heated to prevent clogging due to freezing.

  Further, the liquid supply port 164 formed in the adapter 160 is used only for supplying the cryogen 11 in the initial stage of operation or replenishing the liquid when the small refrigerator 150 is out of order. Since the transfer tube insertion tube 165 extending to the inner container 110 side is connected, the intrusion heat through the liquid supply port 164 is not small. Therefore, it is desirable to devise the structure of the liquid supply port 164 as shown in FIG. 4 to keep the intrusion heat from this portion smaller.

  That is, the transfer tube insertion tube 165 has a double tube structure of an outer tube 201 and an inner tube 202, and both ends thereof are closed and kept in a vacuum by a vacuum seal 203 therebetween. The room temperature portion 204 bent into an L shape from the transfer tube insertion tube 165 is inserted into a port 205 provided in the adapter 160 and is kept airtight by an O-ring 206 and a holding member 207. The transfer tube 208 is inserted into the inner tube 202 of the transfer tube insertion tube 165 via the connection adapter 209. The connection adapter 209 is provided with O-rings 210 and 211 and restrainers 212 and 213 at both ends, so that airtightness is maintained.

DESCRIPTION OF SYMBOLS 10 ... Cooling object 11 ... Cryogenic agent 100 ... Cryogenic device 110 ... Inner container 120 ... Outer container 140 ... Neck tube 150 ... Small refrigerator 165 ... Transfer tube insertion tube 170 ... Partition cover 171 ... Lid member 172 ... Liquid passage 173 ... Communication hole 174 ... Electric heater C ... Conductor S1 ... First gap S2 ... Second gap

Claims (3)

A cryogenic device comprising an inner container for accommodating a body to be cooled together with a cryogen, and an outer container for accommodating the inner container,
Forming a neck tube penetrating the outer container from the inner container, and attaching the refrigerator to fit in the neck tube;
A partition cover is provided so as to surround the refrigerator in the neck tube,
A gas supply port is connected to the first gap formed inside the partition cover, and a gas discharge port is formed in the second gap formed outside the partition cover,
A cryogenic apparatus characterized in that the gas discharge port and the gas supply port are connected by a gas circulation line. A cryogenic device comprising an inner container for accommodating a body to be cooled together with a cryogen, and an outer container for accommodating the inner container,
Forming a neck tube penetrating the outer container from the inner container, and attaching the refrigerator to fit in the neck tube;
A partition cover is provided so as to surround the refrigerator in the neck tube, and a communication hole is formed in the partition cover to form a first gap formed inside the partition cover, and formed outside the partition cover. Communicating with the second gap
A cryogenic device characterized in that the opening end of the partition cover is closed with a lid member having a liquid passage. The cryogenic apparatus according to claim 1 or 2,
A cryogenic apparatus characterized in that a conductive wire connected to the object to be cooled and a pipe for supplying the cryogen are arranged in the second gap.

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