Superconducting magnet
A superconducting magnet includes: a superconducting coil; a coolant container; a radiation shield; a vacuum container; a refrigerator configured to cool the inner part of the coolant container and the radiation shield; a first exhaust pipe connected to the coolant container from the outside of the vacuum container and serving as a flow path of the coolant vaporized; a first pressure release valve connected to a distal end of the first exhaust pipe outside the vacuum container and configured to open when a pressure in the coolant container becomes a first set value or higher; a heater provided at the first exhaust pipe and configured to heat the first exhaust pipe; and a detector provided at the first exhaust pipe and configured to detect a change due to occurrence of freezing in the first exhaust pipe.
1. A superconducting magnet comprising:
a superconducting coil;
a coolant container containing the superconducting coil in a state where the superconducting coil is immersed in liquid coolant;
a radiation shield surrounding the coolant container;
a vacuum container containing the superconducting coil, the coolant container, and the radiation shield;
a refrigerator configured to cool an inner part of the coolant container and the radiation shield;
a first exhaust pipe connected to the coolant container from outside of the vacuum container and serving as a flow path of the coolant vaporized;
a first pressure release valve connected to a distal end of the first exhaust pipe outside the vacuum container and configured to open when a pressure in the coolant container becomes a first set value or higher;
a heater disposed inside the first exhaust pipe and configured to heat the first exhaust pipe; and
a detector provided at the first exhaust pipe and configured to detect a change due to occurrence of freezing in the first exhaust pipe,
the detector including a pair of terminals disposed inside the first exhaust pipe,
the change being a change in potential difference between the terminals of the pair.
2. The superconducting magnet according to claim 1 , the superconducting magnet further comprising a controller electrically connected to each of the heater and the detector, wherein
the controller is configured to cause the heater to work while the controller is receiving input of a signal output from the detector detecting the change.
3. The superconducting magnet according to claim 2 , wherein the heater is provided along an inner periphery of the first exhaust pipe.
4. The superconducting magnet according to claim 1 , wherein the heater is provided along an inner periphery of the first exhaust pipe.
5. A superconducting magnet comprising:
a superconducting coil;
a coolant container containing the superconducting coil in a state where the superconducting coil is immersed in liquid coolant;
a radiation shield surrounding the coolant container;
a vacuum container containing the superconducting coil, the coolant container, and the radiation shield;
a refrigerator configured to cool an inner part of the coolant container and the radiation shield;
a first exhaust pipe connected to the coolant container from outside of the vacuum container and serving as a flow path of the coolant vaporized;
a first pressure release valve connected to a distal end of the first exhaust pipe outside the vacuum container and configured to open when a pressure in the coolant container becomes a first set value or higher;
a heater disposed inside the first exhaust pipe and configured to heat the first exhaust pipe; and
a detector provided at the first exhaust pipe and configured to detect a change due to occurrence of freezing in the first exhaust pipe;
a second exhaust pipe extending from outside of the vacuum container through to inside of the coolant container and serving as a flow path of the coolant vaporized; and
a second pressure release valve connected to a distal end of the second exhaust pipe outside the vacuum container and configured to open when a pressure in the coolant container becomes a second set value or higher, the second set value being higher than the first set value,
a portion of the second exhaust pipe on a side adjacent to the coolant container lying inside the first exhaust pipe, with a space lying between the portion and the first exhaust pipe,
a portion of the second exhaust pipe on a side opposite to the coolant container extending through the first exhaust pipe to outside of the vacuum container,
each of the first exhaust pipe and the second exhaust pipe being formed of a conductive member,
the first exhaust pipe and the second exhaust pipe being electrically insulated from each other at a portion where the second exhaust pipe passes through the first exhaust pipe,
the detector including a pair of terminals, one of the terminals being electrically connected to the first exhaust pipe, the other of the terminals being electrically connected to the second exhaust pipe,
the change being a change in potential difference between the terminals of the pair.
6. The superconducting magnet according to claim 5 , the superconducting magnet further comprising a controller electrically connected to each of the heater and the detector, wherein
the controller is configured to cause the heater to work while the controller is receiving input of a signal output from the detector detecting the change.
7. The superconducting magnet according to claim 6 , wherein the heater is provided along an inner periphery of the first exhaust pipe.
8. The superconducting magnet according to claim 5 , wherein the heater is provided along an inner periphery of the first exhaust pipe.
9. A superconducting magnet comprising:
a superconducting coil;
a coolant container containing the superconducting coil in a state where the superconducting coil is immersed in liquid coolant;
a radiation shield surrounding the coolant container;
a vacuum container containing the superconducting coil, the coolant container, and the radiation shield;
a refrigerator configured to cool an inner part of the coolant container and the radiation shield;
a first exhaust pipe connected to the coolant container from outside of the vacuum container and serving as a flow path of the coolant vaporized;
a first pressure release valve connected to a distal end of the first exhaust pipe outside the vacuum container and configured to open when a pressure in the coolant container becomes a first set value or higher;
a heater disposed inside the first exhaust pipe and configured to heat the first exhaust pipe; and
a detector provided at the first exhaust pipe and configured to detect a change due to occurrence of freezing in the first exhaust pipe in a state where the first exhaust pipe is not clogged up.
10. The superconducting magnet according to claim 9 , the superconducting magnet further comprising a controller electrically connected to each of the heater and the detector, wherein
the controller is configured to cause the heater to work while the controller is receiving input of a signal output from the detector detecting the change.
11. The superconducting magnet according to claim 10 , wherein the heater is provided along an inner periphery of the first exhaust pipe.
12. The superconducting magnet according to claim 9 , wherein the heater is provided along an inner periphery of the first exhaust pipe.