JP4814630B2 - Superconducting magnet system - Google Patents

Description

The present invention relates to a superconducting electromagnet apparatus used for MRI or the like provided with a superconducting coil cooled by liquid helium stored in a helium container.

Generally, an electromagnet device used for magnetic resonance imaging using nuclear magnetic resonance is configured to cool a plurality of annular superconducting coils by immersing them in liquid helium stored in a helium vessel. ing. This liquid helium immersion superconducting electromagnet apparatus maintains the superconducting state by keeping the superconducting coil at a cryogenic temperature of 4.2 K with liquid helium.

  A conventional liquid helium immersion type superconducting electromagnet apparatus includes a superconducting coil, a helium container that houses the superconducting coil and liquid helium, a vacuum container that houses the helium container and is vacuum-insulated by evacuating the inside, and a helium container And a vacuum vessel, mainly composed of a heat shield that reduces radiant heat entering the helium vessel, a discharge pipe for discharging the evaporated helium gas from the helium vessel, and an injection port that is an inlet for injecting liquid helium. The (For example, see Patent Document 1)

  In this conventional apparatus, liquid helium is stored in the helium container, but liquid helium is evaporated little by little during normal operation due to heat penetration from the outside. Further, when the superconducting coil causes superconducting breakdown (quenching), liquid helium is rapidly evaporated by the heat generated by the superconducting coil, and a large amount of helium gas is generated. In order to prevent an increase in internal pressure due to the helium gas, a helium gas discharge pipe is installed in the helium container. There are two valves in the discharge pipe, a check valve and an emergency valve. This check valve functions to release helium gas and prevent inflow of outside air when the internal pressure of the helium container exceeds a certain threshold value during normal operation. The emergency valve is formed to perform an opening operation when the superconducting coil is quenched and a large amount of helium gas is rapidly generated.

  There is also a superconducting electromagnet apparatus in which helium container is provided with means for discharging helium gas to prevent quenching of the superconducting coil, in addition to discharge for suppressing an increase in internal pressure of the helium container. In the case of this conventional apparatus, a 4K (K; Kelvin) refrigerator having a Joule-Thomson expansion circuit compressor (hereinafter referred to as a JT circuit compressor) that condenses the helium gas in the helium container, and the internal pressure of the helium container are detected. And a solenoid valve that discharges helium gas in the helium container. (For example, see Patent Document 2)

  In this conventional apparatus, the operation start of the JT circuit compressor of the 4K refrigerator is set to the upper set value of the helium vessel internal pressure or higher, and the helium gas discharge electromagnetic valve is opened simultaneously with the start of the operation of the JT circuit compressor, The helium gas discharge solenoid valve is closed below the lower set pressure. This reduces the amount of heat entering the helium vessel due to the rise in the condenser temperature at the start of the refrigerator, and prevents a sudden rise in the helium vessel internal pressure and occurrence of quenching of the superconducting coil.

JP-A-5-55032 JP-A-5-335636

  When energizing or demagnetizing the superconducting electromagnet device, the superconducting coil is energized from the external power supply device through the current lead. At this time, the current lead, which is a normal conductor, generates heat, and the generated helium gas warms the surrounding helium gas. Then, hot gas, which is helium gas whose temperature has risen, is generated. Since the conventional superconducting electromagnet apparatus is not provided with means for efficiently discharging hot gas, the generated hot gas accumulates inside the helium container. As a result, the hot gas touches the superconducting coil to cause quenching, and the function as a superconducting electromagnet device is lost.

  In particular, recently, there is a tendency to provide a shield coil having a large diameter for the purpose of reducing the magnetic field spreading outside the superconducting electromagnet apparatus in addition to the main coil that generates a magnetic field at the center of the superconducting electromagnet apparatus. For this reason, the outer diameters of the shield coil and the helium vessel are close to each other, and when a small amount of hot gas is generated, the shield coil is overheated and tends to be quenched.

  Further, when liquid helium is injected while the superconducting electromagnet apparatus is excited, the liquid helium transfer pipe is not sufficiently cooled immediately after the start of injection, and hot gas may enter from the injection pipe. Also in this case, since the conventional superconducting electromagnet apparatus is not provided with means for efficiently discharging the hot gas, the generated hot gas is accumulated in the helium container, causing a quench.

  The present invention has been made in order to solve the problems in the conventional apparatus as described above. By exciting the hot gas generated or intruded into the helium vessel to the outside, it is excited or It is an object of the present invention to obtain a superconducting electromagnet apparatus that is difficult to quench during demagnetization and liquid helium injection.

A superconducting electromagnet apparatus according to the present invention includes a superconducting coil, a helium container that stores liquid helium that houses the superconducting coil and cools the superconducting coil, and a vacuum container that houses the helium container and is held in a vacuum. A current shield provided inside the vacuum vessel and disposed outside the helium vessel, and a normal conductor connected to the superconducting coil and drawn out of the helium vessel from the inner space of the helium vessel. lead and, an injection port capable of injecting a liquid helium inside the helium vessel through the liquid helium transfer tube provided outside of the helium vessel, helium and opening into the internal space of the helium vessel within the interior space a superconducting magnet device provided with a discharge means capable of discharging gas to the outside of the helium vessel, the helium A heater which is immersed in the liquid helium stored in the container, and a power supply device for a heater for supplying power to the heater, the heater, and during injection of the liquid helium at the time of energization of the current lead At least one of them is configured to be energized by receiving power from the heater power supply, and the discharging means is configured to be opened when the heater is energized. It is what has been .

The superconducting electromagnet apparatus according to the present invention includes a superconducting coil, a helium container that stores the superconducting coil and stores liquid helium that cools the superconducting coil, and a vacuum that houses the helium container and is maintained in a vacuum. A container, a heat shield provided inside the vacuum container and disposed outside the helium container, and a normal conductor connected to the superconducting coil and drawn from the internal space of the helium container to the outside of the helium container a current lead comprising, a superconducting magnet device provided with an injection port capable of injecting a liquid helium inside the helium vessel through the liquid helium transfer tube provided outside of the helium vessel, the said helium vessel possess openings at positions other than the vertical direction the top of the interior space, the helium vessel and its opening near the helium gas A first discharge means capable of discharging to the outside, have a opening in a substantially vertical direction at the top position of the inner space of the helium vessel, and discharges the opening vicinity of the helium gas to the outside of the helium vessel Second discharge means for obtaining , wherein the current lead is drawn from the inner space of the helium container to the outside of the helium container in the vicinity of the opening of the first discharge means, and at least the second The discharging means is configured to be opened when at least one of energization of the current lead and injection of the liquid helium .

Furthermore, the superconducting electromagnet apparatus according to the present invention includes a superconducting coil, a helium container storing liquid helium that houses the superconducting coil and cools the superconducting coil, and a vacuum that houses the helium container and is maintained in a vacuum. A container, a heat shield provided inside the vacuum container and disposed outside the helium container, and a normal conductor connected to the superconducting coil and drawn from the internal space of the helium container to the outside of the helium container A current lead, an injection port through which liquid helium can be injected into the helium container via a liquid helium transfer pipe provided outside the helium container, and an opening in the internal space of the helium container. A superconducting electromagnet apparatus comprising: a discharging means capable of discharging the helium gas of the gas to the outside of the helium container, A partition plate partitioning the internal space in the vicinity of the provided in the internal space of helium container said opening from at least the superconducting coil, a heater immersed in the liquid helium stored in the helium vessel, power to the heater And the partition plate prevents contact between the helium gas existing in the vicinity of the opening and the superconducting coil, and the heater is electrically connected to the current lead and the At least one of the injection of liquid helium is configured to be energized by receiving power supply from the heater power supply device .

According to the superconducting electromagnet apparatus according to the present invention, approximately the boiling point of liquid helium by generating low temperature helium gas in the vicinity of 4.2 K, forced hot gas can be discharged to the outside of the helium vessel by the heater, The superconducting coil is not caused to quench by hot gas, and a highly reliable superconducting electromagnet apparatus can be provided.

According to the superconducting electromagnet apparatus according to the present invention, the first discharge means having an opening at a position other than the vertical uppermost part of the inner space of the helium container, and the uppermost part of the inner space of the helium container in the substantially vertical direction. A second discharge means having an opening at a position, and the second discharge means can discharge hot gas to the outside of the helium container, and the hot gas is effectively discharged to the outside of the helium container. The coil does not cause quenching by hot gas, and a highly reliable superconducting electromagnet apparatus can be provided.

Furthermore, according to the superconducting electromagnet apparatus according to the present invention, the inner space of the helium vessel, since a partition plate that partitions said internal space in the vicinity of the opening of the discharge means from at least the superconducting coil, the hot gas is at least a superconducting It is possible to provide a highly reliable superconducting electromagnet apparatus in which the coil is prevented from touching and the superconducting coil is not quenched by hot gas.

Embodiment 1
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a superconducting electromagnet apparatus for MRI according to Embodiment 1 of the present invention. The main coil 1a has a small diameter that generates a necessary magnetic field mainly at the center of the superconducting electromagnet apparatus, and the outer periphery of the superconducting electromagnet apparatus. The superconducting coil 1 which consists of the large diameter shield coil 1b which reduces the magnetic field of a part is provided. The superconducting coil 1 is provided inside a helium container 3 that stores liquid helium 2 and is immersed in the liquid helium 2 to maintain a superconducting state.

  The superconducting coil 1 is connected to an excitation power supply 13 through a current lead 12 made of a normal conductor drawn from the inside of the helium vessel 3 to the outside. Demagnetized.

The helium vessel 3 is housed inside a vacuum vessel 5 whose inside is maintained in a vacuum, and is vacuum insulated from the outside of the vacuum vessel 5. Further, the helium vessel 3 is surrounded by a heat shield 4 provided inside a cryostat 5 as a vacuum vessel, and is mainly shielded from radiant heat from the cryostat 5.

  The refrigerator unit 10 is thermally connected to the heat shield 4 and is partially inserted into the internal space of the helium container 3. The refrigerator unit 10 includes a 4K refrigerator, is connected to the compressor unit 11 by a gas hose, and is supplied with high-pressure helium gas. The compressor unit 11 includes a JT circuit compressor that condenses helium gas.

  The heater 6 is immersed in the liquid helium 2, and receives heat from the heater power supply 7 to generate heat. The helium container 3 is provided with a discharge means 8. The discharge means 8 includes a check valve 8 a, an emergency valve 8 b, and a discharge pipe 80. The discharge pipe 80 is an internal space of the protrusion 31 provided at the top of the helium container 3, that is, an internal space of the helium container 3. Open in the vertical uppermost part (hereinafter referred to as the uppermost part) 32. The check valve 8 a is opened when the heater 6 is energized. The check valve 8a is opened or closed manually or automatically. Further, the discharge pipe 80 is provided with an injection port 9 for injecting liquid helium into the helium container 3.

  In the superconducting magnet device according to Embodiment 1 of the present invention configured as described above, in order to obtain a desired magnetic field, the exciting power supply device 13 and the current lead 12 of the superconducting electromagnet device are connected, and the current is supplied to the superconducting coil 1. To excite. Thereafter, the connection between the exciting power supply device 13 and the current lead 12 is disconnected, and the superconducting coil 1 operates in a superconducting state to generate a desired magnetic field. Usually, there is a slight heat intrusion into the helium vessel 3 from the outside of the cryostat 5 and the helium vessel 3, and the liquid helium 2 evaporates little by little. Therefore, the temperatures of the liquid helium 2, the superconducting coil 1, the helium vessel 3, and the heater 6 are kept equal to 4.2 K, which is the boiling point of the liquid helium 2.

  However, the material constituting the current lead 12 is not a superconducting material, and generates Joule heat having a heat quantity proportional to the square of the current due to its resistance component when the superconducting coil 1 is excited. This heat warms the helium gas around the current lead 12 and generates hot gas. The hot gas has a specific gravity smaller than that of cold helium gas, so that it accumulates in the upper part in the vertical direction (hereinafter referred to as the upper part) of the internal space of the helium container 3.

  At this time, the heater 6 immersed in the liquid helium 2 is energized. Since the heater 6 is surrounded by the liquid helium 2, the Joule heat generated by energizing the heater 6 is used only to vaporize the surrounding liquid helium 2 and exists in the internal space of the helium container 3. The helium gas and the temperature of the heater 6 do not rise. Therefore, the temperature of the helium gas generated by the heat generation of the heater 6 is 4.2 K which is equal to the boiling point of the liquid helium 2.

  The check valve 8 a is opened simultaneously with the energization of the heater 6, and 4.2 K helium gas generated by the heat generated by the heater 6 passes through the check valve 8 a through hot gas accumulated in the upper part of the internal space of the helium container 3. Forcibly discharged from the helium container 3 to the outside. When the energization of the heater 6 is finished and the hot gas discharge is finished, the check valve 8a is closed. In this manner, the check valve 8a is opened when the heater 6 is energized to discharge hot gas, and is normally closed, so that helium gas does not leak normally.

  On the other hand, the heat penetration amount into the cryostat 5 is usually 1 W or less. The heater 6 has a resistance value of 120 [Ω], for example, and generates 30 [W] Joule heat by energizing a current of 0.5 [A]. Therefore, the amount of helium gas generated when the heater 6 is energized is 30 times or more that when the heater 6 is not energized.

  The conventional superconducting electromagnet apparatus generates only the helium gas for the heat intrusion of 1 W or less, and cannot exhaust the hot gas sufficiently. However, in the first embodiment, the hot gas can be sufficiently forcibly discharged by the heat generated by the heater 6, so that hot gas is prevented from accumulating in the helium container 3 during excitation, and the hot gas touches the superconducting coil 1. It is possible to prevent the occurrence of quenching.

  The demagnetization of the superconducting electromagnet device is achieved by connecting the exciting power supply device 13 and the current lead 12 of the superconducting electromagnet device, consuming energy by the resistance inside the exciting power supply 13 and reducing the current flowing through the superconducting coil 1. Do. Also in this case, since the current lead 12 generates heat having a quantity of heat proportional to the square of the current, hot gas accumulates in the upper portion of the helium container 3 as described above.

  Also at this time, as described above, the heater 6 is energized to generate helium gas having a temperature of 4.2 K, so that the hot gas accumulated in the upper part of the internal space of the helium vessel 3 can be forcibly discharged from the helium vessel 3 to the outside. it can. This prevents hot gas from accumulating in the helium container during demagnetization and avoids quenching caused by the hot gas touching the superconducting coil 1.

  In order to inject liquid helium into the superconducting electromagnet apparatus, one end of a liquid helium transfer pipe (not shown) is inserted into the injection port 9 and the other end is inserted into a liquid helium storage container (not shown). The container side is pressurized with helium gas to move liquid helium to the helium container 3. At this time, if the liquid helium transfer pipe is not sufficiently cooled, hot gas is generated by the heat of the liquid helium transfer pipe, and the hot gas enters the helium container 3 from the injection port 9.

  Also in this case, the heater 6 is energized as described above to generate helium gas having a temperature of 4.2 K, so that the hot gas accumulated in the upper part of the internal space of the helium container 3 is forcibly discharged from the helium container 3 to the outside. be able to. This prevents hot gas from accumulating in the helium container 3 during liquid helium injection and avoids the occurrence of quenching caused by the hot gas touching the superconducting coil 1.

Embodiment 2
FIG. 2 is a cross-sectional view of the superconducting electromagnet apparatus according to Embodiment 2 of the present invention. In FIG. 2, the discharge pipe 80 opens into the internal space 32 of the protruding portion 31 of the helium container 3. The protruding portion 31 of the helium container 3 is provided at an oblique upper portion that is disengaged from the top of the helium container. is there. The discharge pipe 80, the emergency valve 8b, and the check valve 8a constitute first discharge means 80.

  The helium container 3 is further provided with a hot gas discharge pipe 14, and the hot gas discharge pipe 14 is provided with an opening that opens to the uppermost portion 33 of the internal space of the helium container 3. The hot gas discharge pipe 14 is disposed along the outer surface of the helium container 3, and an end thereof is opened to the atmosphere via a check valve 8 c. The hot gas discharge pipe 14 and the check valve 8c constitute second discharge means.

  In the second embodiment, the hot gas discharge pipe 14 having an opening is provided at the uppermost portion 33 of the internal space of the helium vessel 3, and the protruding portion 31 of the helium vessel 3 is provided obliquely above the helium vessel 3. In addition, the refrigeration unit 10 and the current lead 12 provided in the projecting portion 31 are installed not in the uppermost portion of the helium vessel 3 but in an oblique upper portion, and the discharge pipe provided in the projecting portion 31 of the helium vessel 3 80 differs from the first embodiment in that it has an opening that opens at a position deviated from the top of the internal space of the helium container 3 and that it does not include a heater and a heater power source. Other configurations are the same as those in the first embodiment.

  In the second embodiment, since the discharge pipe 80, the injection port 9, the refrigerator unit 10, and the current lead 12 are installed obliquely above the helium container, the overall height of the superconducting electromagnet apparatus can be kept low.

  Next, the operation of the superconducting electromagnet apparatus according to Embodiment 2 will be described. As described above, when the superconducting electromagnet apparatus is excited and demagnetized, hot gas is generated by the heat generation of the current leads 12 as in the first embodiment. This hot gas is accumulated around the current lead 12 in the internal space 32, around the opening of the discharge pipe 80, and at the uppermost portion 33 of the internal space.

  In the second embodiment, hot gas accumulated in the inner space 32 around the current lead 12 and around the opening of the discharge pipe 80 is directly discharged to the outside through the check valve 8a by the discharge pipe 80, and helium Hot gas accumulated in the uppermost portion 33 of the internal space of the container 3 is discharged to the outside through the check valve 8c by the hot gas discharge pipe 14.

  As described above, in the superconducting electromagnet apparatus according to the second embodiment, the discharge pipe 80, the injection port 9, the refrigerator unit 10, and the current lead 12 are arranged obliquely above the helium vessel 3 and the overall height of the superconducting electromagnet apparatus is kept low. However, during excitation of the superconducting coil 1, hot gas can be prevented from accumulating in the helium container, and the occurrence of quenching caused by the hot gas touching the superconducting coil 1 can be avoided.

  In addition to the case where hot gas is generated by the heat generation of the current lead 12 during excitation and demagnetization of the superconducting electromagnet apparatus, when the hot gas enters the helium container 3 when liquid helium is injected into the helium container 3, Similarly, the gas can be discharged from the helium container 3 via the discharge pipe 80 and the hot gas discharge pipe 14 to prevent the hot gas from accumulating in the helium container and the hot gas touches the superconducting coil 1. The occurrence of quenching can be avoided.

  Although the heater and the heater power source are not provided in the second embodiment, a heater immersed in the liquid helium 2 and the heater power source may be provided as in the first embodiment. In this case, the hot gas can be discharged more effectively to the outside of the helium container. In this case, the check valve 8 c provided in the second discharge means is opened when the heater 6 is energized. The check valve 8c is opened and closed manually or automatically. The check valve 8a is opened when the heater 6 is energized to discharge hot gas, and is normally closed, so that helium gas does not leak normally.

Embodiment 3
In the second embodiment, the hot gas discharge pipe 14 is directly opened to the atmosphere via the check valve 8c to release the hot gas. However, in the third embodiment, as shown in FIG. Even if the gas discharge pipe 14 is connected to the discharge pipe 80 outside the helium vessel 3 and inside the heat shield 4, the same effect as in the second embodiment can be expected. In the third embodiment, the check valve 8c of the hot gas discharge pipe 14 provided in the second embodiment can be omitted. Other configurations are the same as those of the second embodiment.

  As in the first embodiment, a heater immersed in the liquid helium 2 and a power source for the heater may be provided. In this case, the hot gas can be discharged more effectively to the outside of the helium container. In this case, the check valve 8 a provided in the discharge means 8 is opened when the heater 6 is energized. The check valve 8a is opened or closed manually or automatically.

Embodiment 4
FIG. 4 is a cross-sectional view of a surface parallel to the coil axis of the superconducting electromagnet apparatus according to Embodiment 4 of the present invention. In FIG. 4, 151 and 152 are a pair of partition plates provided in the upper part of the internal space of the helium vessel 3. The partition plates 151 and 152 are provided so as to partition the vicinity of the internal space 32 of the protruding portion 31 of the helium container 3 from other internal spaces, and accordingly, the shield coil 1b, the discharge pipe 80, the injection port 9, and the refrigerator. The unit 10 and the current lead 12 are partitioned by partition plates 151 and 152. Other configurations are the same as those of the first embodiment.

  Next, the operation of the fourth embodiment will be described. When the superconducting electromagnet apparatus is excited and demagnetized, hot gas is generated due to heat generated by the current lead 12. Hot gas is also generated when liquid helium is injected into the helium container 3. However, in the fourth embodiment, since the internal space 32 where the current lead 12 is present and the internal space where the shield coil 1b is present are partitioned by the partition plates 151 and 152, the internal space 32 where the current lead 12 is present is hot. Even if the gas accumulates to some extent, the shield coil 1b is not touched, and the occurrence of quenching caused by the hot gas touching the superconducting coil 1 can be avoided.

  Although the heater and the heater power source are not provided in the fourth embodiment, a heater immersed in the liquid helium 2 and the heater power source may be provided as in the first embodiment. In this case, the hot gas can be effectively discharged outside the helium container. In this case, the check valve 8 a provided in the discharge means 8 is opened when the heater 6 is energized. The check valve 8a is opened or closed manually or automatically. The check valve 8a is opened when the heater 6 is energized to discharge hot gas, and is normally closed, so that helium gas does not leak normally.

Embodiment 5
In the first to fourth embodiments, hot gas or helium gas generated by a heater is discharged to the outside of the helium container through the check valve. Generally, the check valve has a small flow rate and is sufficiently hot gas or Helium gas may not be discharged. Therefore, in the fifth embodiment, as shown in FIG. 5, in addition to the check valve 8a, a hot gas discharge valve 8d and a helium gas flow path 141 for the hot gas discharge valve 8d are provided.

  This hot gas discharge valve 8d is opened when the heater 6 is energized during excitation and demagnetization of the superconducting coil 1 and liquid helium injection, and discharges hot gas and helium gas, and is closed otherwise. The opening / closing operation may be manual or automatic control. Other configurations are the same as those in any one of the first to fourth embodiments.

  According to the fifth embodiment, by providing the hot gas discharge valve 8d, the hot gas or the helium gas generated by the heater can be discharged efficiently.

It is sectional drawing of a surface perpendicular | vertical to the axis | shaft of the coil of the superconducting electromagnet apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing of the surface perpendicular | vertical to the axis | shaft of the coil of the superconducting electromagnet apparatus which concerns on Embodiment 2 of this invention. It is sectional drawing of the surface perpendicular | vertical to the axis | shaft of the coil of the superconducting electromagnet apparatus which concerns on Embodiment 3 of this invention. It is sectional drawing of the surface parallel to the axis | shaft of the coil of the superconducting electromagnet apparatus which concerns on Embodiment 4 of this invention. The enlarged view of the discharge pipe part of the superconducting electromagnet apparatus which concerns on Embodiment 5 of this invention is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Superconducting coil 1a Main coil 1b Shield coil 2 Liquid helium 3 Helium container 31 Protruding part 32, 33 Internal space 4 Heat shield 5 Cryostat 6 Heater 7 Heater power supply 8 Discharge means 8a, 8c Check valve 8b Emergency valve 8d Hot gas discharge Valve 9 Injection port 10 Refrigerator unit 11 Compressor unit 12 Current lead 13 Excitation power supply device 14 Hot gas exhaust pipe 80 Exhaust pipe 151, 152 Partition plate

Claims (8)

A superconducting coil; a helium container that stores liquid helium that houses the superconducting coil and cools the superconducting coil; a vacuum container that houses the helium container and is held in vacuum; and is provided inside the vacuum container. A heat shield disposed outside the helium vessel, a current lead made of a normal conductor connected to the superconducting coil and drawn out from the inner space of the helium vessel to the outside of the helium vessel, and external to the helium vessel An injection port through which liquid helium can be injected into the inside of the helium vessel via a liquid helium transfer pipe provided; and an opening in the internal space of the helium vessel that discharges helium gas in the internal space to the outside of the helium vessel. A superconducting electromagnet device having a discharge means capable of
A heater immersed in the liquid helium stored in the helium container;
A heater power supply for supplying power to the heater;
With
The heaters, when at least either one of a time of injection of the liquid helium at the time of energization of the current lead, adapted to be energized by power supply from the heaters for power supply And
Said discharge means, said heaters are configured to be opened when the urging it superconducting electromagnet apparatus according to claim.   The superconducting electromagnet apparatus according to claim 1, wherein the discharging unit includes a valve that opens the discharging unit when the heater is energized. A superconducting coil; a helium container that stores liquid helium that houses the superconducting coil and cools the superconducting coil; a vacuum container that houses the helium container and is held in vacuum; and is provided inside the vacuum container. A heat shield disposed outside the helium vessel, a current lead made of a normal conductor connected to the superconducting coil and drawn out from the inner space of the helium vessel to the outside of the helium vessel, and external to the helium vessel A superconducting electromagnet apparatus comprising an injection port capable of injecting liquid helium into the helium vessel via a liquid helium transfer pipe provided;
A first discharge means having an opening at a position other than the vertical uppermost portion of the internal space of the helium container, and capable of discharging the helium gas in the vicinity of the opening to the outside of the helium container; A second discharge means having an opening at a position substantially at the top in the vertical direction of the internal space and capable of discharging the helium gas in the vicinity of the opening to the outside of the helium container;
With
The current lead is drawn out from the inner space of the helium container to the outside of the helium container in the vicinity of the opening of the first discharge means,
At least the second discharge means is configured to be opened at least one of energization of the current lead and at the time of injection of the liquid helium.
A superconducting electromagnet device. The superconducting electromagnet apparatus according to claim 3 , wherein the second discharging means is connected to the first discharging means at a position other than the respective openings. A heater immersed in the liquid helium stored in the helium container;
A heater power supply for supplying power to the heater;
With
The heaters, when at least either one of a time of injection of the liquid helium at the time of energization of the current lead, adapted to be energized by power supply from the heaters for power supply Being
The superconducting electromagnet apparatus according to claim 3 or 4,   The superconducting electromagnet apparatus according to claim 5, wherein the second discharge unit includes a valve that is opened when power is supplied to the heater. A superconducting coil; a helium container that stores liquid helium that houses the superconducting coil and cools the superconducting coil; a vacuum container that houses the helium container and is held in vacuum; and is provided inside the vacuum container. A heat shield disposed outside the helium vessel, a current lead made of a normal conductor connected to the superconducting coil and drawn out from the inner space of the helium vessel to the outside of the helium vessel, and external to the helium vessel An injection port through which liquid helium can be injected into the inside of the helium vessel via a liquid helium transfer pipe provided; and an opening in the internal space of the helium vessel that discharges helium gas in the internal space to the outside of the helium vessel. A superconducting electromagnet device having a discharge means capable of
A partition plate provided in the internal space of the helium vessel and partitioning the internal space near the opening from at least the superconducting coil;
A heater immersed in the liquid helium stored in the helium container;
A heater power supply for supplying power to the heater;
With
The partition plate prevents helium gas existing in the vicinity of the opening and the superconducting coil from contacting each other,
The heater is configured to be energized with power supplied from the heater power supply device at least one of energizing the current lead and injecting the liquid helium. Yes,
A superconducting electromagnet device. The discharge means is provided with a valve that opens the discharge means when the heater is energized,
The superconducting electromagnet apparatus according to claim 7 .

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