JP3625043B2 - Helium reliquefaction equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an evaporative helium gas reliquefaction apparatus for an apparatus that uses liquid helium as a cryogen (hereinafter referred to as “liquid helium apparatus”), such as a SQUID (superconducting quantum interferometer) apparatus or an SCM (superconducting magnet). .
[0002]
[Prior art]
In general, the helium reliquefaction apparatus collects helium gas evaporated from the liquid helium tank of the liquid helium apparatus at room temperature or low temperature, and recondenses it in the reliquefaction apparatus and returns it to the liquid helium tank.
[0003]
An adiabatic connection pipe is used to connect the low-temperature fluid between the reliquefaction device and the liquid helium device. Insert the insulation connection pipe attached to the reliquefaction device into the insertion port on the liquid helium device side to make the connection. The vaporized gas from the liquid helium device is recovered to the reliquefaction device side through the heat insulation connecting pipe, and the liquid helium recondensed by the reliquefaction device is returned to the liquid helium device.
[0004]
The heat insulating connecting pipe is inserted into an insertion port provided on the upper surface of the liquid helium apparatus. Since the tip of the heat insulating connecting pipe is inserted into the liquid helium tank of the liquid helium apparatus, the insertion depth is usually 40 cm or more. Therefore, when attaching and detaching the heat insulating connecting pipe, an elevating device that moves up and down including the heat insulating connecting pipe and the reliquefaction unit connected thereto is required.
[0005]
In the conventional helium reliquefaction apparatus, for example, as shown in FIG. 1, a hydraulic lift 1 is used as the lift. The reliquefaction device 2 is mounted on the hydraulic lifting platform 1 and moved up and down. The heat insulating connecting pipe 3 is directly connected to the vacuum vessel 4 which is the main body of the refrigeration apparatus, and the entire apparatus is moved up and down, so that the lifting load is relatively large, and that the cost is reasonable, This is the reason for selecting the hydraulic lift.
[0006]
[Problems to be solved by the invention]
However, since the conventional helium reliquefaction device uses a hydraulic lifting platform, the hydraulic mechanism operates when it is desired to hold the insertion position in the middle, such as when the reliquefaction device is precooled. Since the oil leaks, the holding position may be gradually lowered.
[0007]
In addition, in the insertion port section of the liquid helium device, it is necessary to perform gas sealing after inserting the heat insulation connection pipe, and it is necessary to reduce the gap between the port diameter and the heat insulation connection pipe diameter. Although required, it is insufficient in accuracy to be lifted and lowered by a hydraulic lift, and a separate guide guide or the like is required.
[0008]
In addition, the hydraulic type usually adjusts the descending speed manually, but it requires fine adjustment, and there is a risk of collision when it is inserted into the port. It will contaminate the installation environment.
[0009]
The present invention solves the problems of the prior art, and does not require a lock mechanism or a guide guide at an intermediate position of the lifting device, and safely inserts and removes the heat insulating connection pipe from the insertion port. It is an object of the present invention to provide a liquid helium reliquefaction device that can be made and does not contaminate the surroundings of the device.
[0010]
[Means for Solving the Problems]
Therefore, in the liquid helium reliquefaction apparatus of the present invention, helium gas evaporated from the liquid helium tank of the liquid helium apparatus is recovered at room temperature or low temperature, and is recondensed in the reliquefaction apparatus and returned to the liquid helium tank. A heat insulating connection pipe inserted into an insertion port provided on an upper surface of the liquid helium apparatus is integrally attached to the reliquefaction apparatus, and the heat insulating connection pipe is connected to the insertion port. An electric linear actuator is used for the lifting device for attaching and detaching, and the electric linear actuator is arranged outside the inner cylinder and fixed to the base plate, and fixed to the base plate and arranged at the center of the inner cylinder. A fixed spindle, an electric motor fixed to the inner wall of the inner cylinder, and fixed to a rotor of the electric motor Characterized in that comprising a rotor shaft which is moved up and down with the rotation of the serial spindle and screwed the rotor.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a front view showing a state in which the heat insulation connecting pipe of the helium reliquefaction apparatus is raised in the embodiment of the present invention, FIG. 3 is a front view showing a state in which the heat insulation connection pipe of the helium reliquefaction apparatus in FIG. 2 is lowered, 4 is a longitudinal sectional view of the lifting device of the helium reliquefaction device of FIG. 2, FIG. 5 is a perspective view of the electric linear actuator of the lifting device of FIG. 4, and (A) is when it is raised, and (B) is when it is lowered. It is a perspective view shown.
[0012]
In the figure, reference numeral 12 denotes a helium reliquefaction device. The helium reliquefaction device 12 collects helium gas evaporated from the liquid helium tank 16 of the liquid helium device 15 at room temperature or low temperature, and the vacuum of the helium reliquefaction device 12 is obtained. It is condensed again in the container 17 and returned to the liquid helium tank 16.
[0013]
An insertion port 18 is provided on the upper surface of the liquid helium device 15. Further, the heat insulating connecting pipe 13 inserted into the insertion port 18 is integrally attached to the reliquefaction device 12. The electric linear actuator 11 is used as an elevating device for attaching / detaching the heat insulating connecting pipe 13 to / from the insertion port 18.
[0014]
The helium reliquefaction device 12 includes an upper casing 19 and a lower casing 20, and the lower casing 20 includes helium gas supply piping system equipment (gas purifier, pressure control valve, flow meter, pressure gauge, etc. (Not shown) and the electric linear actuator 11 are built in and fixed to the base plate 21.
[0015]
The upper casing 19 incorporates an operation control panel 22, and the vacuum vessel 17 is mounted on the upper portion. A heat insulating connecting pipe 13 is integrally attached to a side portion of the vacuum vessel 17. As shown in FIG. 3, the substantially inverted L-shaped heat insulating connecting pipe 13 is moved down together with the upper housing 19 and the vacuum container 17 by lowering the electric linear actuator 11 by operation of the operation control panel 22, and the insertion port. 18 is inserted into the liquid helium tank 16.
[0016]
As shown in FIG. 4, the electric linear actuator 11 includes an outer cylinder 32 disposed outside the inner cylinder 31 and fixed to the base plate 21, and a central portion of the inner cylinder 31 fixed to the base plate 21. The spindle 33, the electric motor 34 fixed to the inner wall of the inner cylinder 31 via the stator 35, and the rotor 36 of the electric motor 34 are fixed to the rotor 36 and screwed with the spindle 33 to rotate the rotor 36. And a rotor shaft 37 that is moved up and down along with.
[0017]
The electric motor 34 includes a stator 35 fixed to the inner cylinder 31 and wound with a coil, and a rotor 36 disposed close to the inner side of the stator 35. The electric motor 34 supplies a current to the coil of the stator 35. By supplying, the rotor 36 can be rotated.
[0018]
Further, a hollow rotor shaft 37 is fixed further inside the rotor 36, and an upper end and a slightly lower part of the rotor shaft 37 are rotatably supported with respect to the stator 35 by bearings 38 and 39. The rotor shaft 37 includes a hollow portion 37 a disposed inside the rotor 36 and a nut portion that extends from the hollow portion 37 a toward the base plate 21 and is screwed to the spindle 33.
[0019]
The spindle 33 is fixed to the base plate 21 with a nut 41 through a bottom plate 40 that closes the bottom of the outer cylinder 32 and is fixed to the base plate 21.
[0020]
Therefore, as shown in FIG. 5, the electric motor 34 is driven by connecting a terminal board 43 attached to the lower portion of the outer cylinder 32 to a power source (not shown), and the rotor 36 is rotated, whereby the nut portion 37b is rotated in the direction of arrow R (FIG. 4), and the rotational motion is converted into linear motion by the rotor shaft 37, the spindle 33, and the bearings 38, 39, and the inner cylinder 31 is not rotated, but along the inner side of the outer cylinder 32. Can be moved up and down in the direction of the arrow L (FIGS. 4 and 5). As a result, the elevator 42 on which the upper casing 19 is fixed to the upper surface can be raised and lowered.
[0021]
【The invention's effect】
As described above in detail, according to the present invention, in the liquid helium reliquefaction device, helium gas evaporated from the liquid helium tank of the liquid helium device is recovered at room temperature or low temperature and recondensed in the reliquefaction device. A helium reliquefaction device that is returned to the liquid helium tank, wherein a heat insulating connection pipe inserted into an insertion port provided on the upper surface of the liquid helium device is integrally attached to the reliquefaction device, and Since the electric linear actuator is used for the lifting device for attaching / detaching the heat insulating connecting pipe to / from the insertion port, the entire device can be made small and simple, and there is a risk of contamination around the device due to oil. There is no.
[0022]
Further, the electric linear actuator includes an outer cylinder disposed outside the inner cylinder and fixed to the base plate;
A spindle fixed to the base plate and disposed at the center of the inner cylinder, an electric motor fixed to the inner wall of the inner cylinder, a rotor fixed to the rotor of the electric motor and screwed to the spindle, and the rotor Since the inner cylinder is guided by the outer cylinder and moves up and down, the lateral accuracy during raising and lowering is improved. Therefore, it is possible to accurately and safely insert and remove the heat-insulating connection pipe from the insertion port.
Moreover, it is an elevating mechanism using an electric motor and a spindle, can be stopped at an arbitrary position, and can be held without lowering the stop position of the heat insulating connecting pipe because of a self-locking mechanism.
[Brief description of the drawings]
FIG. 1 is a front view of a conventional helium reliquefaction apparatus.
FIG. 2 is a front view showing a state in which the heat insulation connecting pipe of the helium reliquefaction apparatus in the embodiment of the present invention is raised.
FIG. 3 is a front view showing a state in which the heat insulation connecting pipe of the helium reliquefaction device of FIG. 2 is lowered;
4 is a longitudinal sectional view of a lifting device of the helium reliquefaction device of FIG.
5A and 5B are perspective views of the electric linear actuator of the elevating device in FIG. 4, in which FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Electric linear actuator 12 Helium reliquefaction apparatus 13 Heat insulation connection pipe 15 Liquid helium apparatus 16 Liquid helium tank 18 Insertion port 19 Upper housing | casing 20 Lower housing 21 Base plate 22 Operation control board 31 Inner cylinder 32 Outer cylinder 33 Spindle 34 Electric motor 36 Rotor 37 Rotor shaft

Claims (1)

A helium reliquefaction device that recovers helium gas evaporated from a liquid helium tank of a liquid helium device at room temperature or low temperature, recondenses in the reliquefaction device, and returns to the liquid helium tank,
A heat insulating connecting pipe inserted into an insertion port provided on the upper surface of the liquid helium apparatus is integrally attached to the reliquefaction apparatus, and an electric linear actuator is installed in a lifting device for attaching / detaching the heat insulating connecting pipe to / from the insertion port. Use
The electric linear actuator includes an outer cylinder disposed outside the inner cylinder and fixed to the base plate, a spindle fixed to the base plate and disposed at a central portion of the inner cylinder, and an inner wall of the inner cylinder. A helium reliquefaction apparatus comprising: an electric motor; and a rotor shaft fixed to a rotor of the electric motor and screwed with the spindle to be moved up and down as the rotor rotates.

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