阅读说明：本技术 直冷磁体用活动式自定位快速降温机械开关及降温方法 (Movable self-positioning rapid cooling mechanical switch for direct cooling magnet and cooling method ) 是由 李超 李勇 刘伟 马鹏 周涛 葛正福 冯勇 张平祥 于 2020-06-28 设计创作，主要内容包括：直冷磁体用活动式自定位快速降温机械开关及降温方法,包括有杜瓦、机械开关、磁体,杜瓦上部设有顶板；顶板上设有吊装结构、抽空接口、气缸；气缸通过波纹管与设在杜瓦内的活动连接导冷装置进行连接和断开；活动连接导冷装置由自定位结构的锥头和锥碗组成,锥碗保持不动,锥头和气缸连接,气缸的上升和下降,实现了锥头和锥碗的连接与断开,从而机动的实现降温控制需求。磁体安装；装入磁体,杜瓦抽空；真空检漏,打开制冷机,打开自定位机械开关,到达预期温度后断开自定位机械开关；这种活动式自定位机械开关解决了磁体在前期冷却过程中降温速度慢的问题；利用大冷量制冷机实现磁体的快速降温,结构简单、实用、可靠,操作方便。(A movable self-positioning rapid cooling mechanical switch for a direct cooling magnet and a cooling method thereof comprise a Dewar, a mechanical switch and a magnet, wherein the upper part of the Dewar is provided with a top plate; the top plate is provided with a hoisting structure, an evacuation interface and a cylinder; the cylinder is connected and disconnected with a movable connection cold-conducting device arranged in the Dewar through a corrugated pipe; the movable connection cold guide device is composed of a conical head and a conical bowl of a self-positioning structure, the conical bowl is kept still, the conical head is connected with the air cylinder, the air cylinder rises and falls, connection and disconnection of the conical head and the conical bowl are achieved, and therefore cooling control requirements are achieved flexibly. Mounting a magnet; putting in a magnet, and evacuating by a Dewar flask; detecting leakage in vacuum, turning on a refrigerator, turning on a self-positioning mechanical switch, and turning off the self-positioning mechanical switch after the preset temperature is reached; the movable self-positioning mechanical switch solves the problem that the cooling speed of the magnet is low in the early cooling process; the quick cooling of the magnet is realized by utilizing the large-cooling-capacity refrigerator, and the device has the advantages of simple structure, practicality, reliability and convenient operation.)

1. A movable self-positioning rapid cooling mechanical switch for a direct cooling magnet comprises a Dewar (9), a cold shield (3), a self-positioning mechanical switch conical bowl (6), a self-positioning mechanical switch conical head (7), a heat-conducting copper strip (8) and a magnet (10); the device is characterized in that the upper part of the Dewar (9) is provided with a cylinder (5), a single-stage refrigerator (4) and a double-stage refrigerator (2); a screw rod, a cold screen, a self-positioning mechanical switch conical bowl (6), a self-positioning mechanical switch conical head (7), a heat-conducting copper strip (8) and a magnet (10) are arranged below a top plate of the Dewar (9);

the output end of the air cylinder (5) is connected with the magnet (10) sequentially through the self-positioning mechanical switch conical bowl (6), the self-positioning mechanical switch conical head (7) and the heat-conducting copper strip I (8); the single-stage refrigerator (4) is communicated with the magnet (10) through a second heat-conducting copper strip (11); the double-stage refrigerator (2) is communicated with the magnet (10).

2. The movable self-positioning fast cooling mechanical switch for the direct cooling magnet according to claim 1, wherein the two-stage refrigerator 2 is connected with the magnet through a heat-conducting copper strip III (12).

3. The movable self-positioning rapid cooling mechanical switch for the direct cooling magnet according to claim 1, wherein the single-stage refrigerator is connected with the cold shield through a heat conducting copper strip.

4. The movable self-positioning rapid cooling mechanical switch for the direct cooling magnet as claimed in claim 1, wherein the cylinder is connected with a conical head of the self-positioning mechanical switch through a corrugated pipe.

5. The movable self-positioning fast cooling mechanical switch for the direct cooling magnet according to claim 1, wherein the self-positioning mechanical switch cone bowl (6) is fixed on the top of the cold shield (3).

6. The movable self-positioning fast cooling mechanical switch for the direct cooling magnet according to claim 1, wherein the self-positioning mechanical switch cone bowl (6) and the self-positioning mechanical switch cone head (7) have the same taper.

7. The mechanical switch of movable self-positioning rapid cooling for direct cooling magnet of claim 1, wherein the magnet (10) is placed on a stage at the bottom and suspended on the top plate of the Dewar (9) through a screw.

8. The movable self-positioning rapid cooling mechanical switch for the direct cooling magnet according to claim 1, wherein a cold screen (3) is fixedly hung on a top plate of the Dewar (9) through a screw rod; and an interface flange (1) is arranged on the top plate of the Dewar (9).

9. The movable self-positioning rapid cooling mechanical switch for the direct cooling magnet according to claim 1, wherein the secondary cold head of the two-stage refrigerator (2) is connected with the magnet (10) through a heat-conducting copper strip (8); the single-stage refrigerator (4) is also respectively connected with a self-positioning mechanical switch conical bowl (6) through a heat-conducting copper strip (8).

10. The method for rapidly cooling the magnet of the movable self-positioning rapid cooling mechanical switch for the direct cooling magnet according to claims 1 to 9, comprising the following steps:

when the superconducting magnet is cooled, the double-stage refrigerator (2) and the single-stage refrigerator (4) are opened, the coil (10) is cooled, the air cylinder (5) is ventilated, the pressure is kept to be 0.1-0.3MPa, the self-positioning mechanical switch conical bowl (6) and the self-positioning mechanical switch conical head (7) are closed, and the high-power single-stage refrigerator (4) cools the coil (10); when the coil (10) is cooled to the lowest temperature of the single-stage refrigerator, the air source of the air cylinder is closed, the self-positioning mechanical switch conical bowl (6) and the self-positioning mechanical switch conical head (7) are opened, the single-stage refrigerator (4) only cools the cold shield (3), and the double-stage refrigerator (2) continues to cool the coil to the required temperature.

Technical Field

The invention belongs to the technical field of low-temperature heat transfer of superconducting magnets, and particularly relates to a movable self-positioning rapid cooling mechanical switch for a direct-cooling magnet and a cooling method.

Background

The stable operation of the superconducting magnet depends on low-temperature conditions, and the superconducting magnet is classified from the creation of the low-temperature conditions and can be divided into two modes of liquid helium soaking cooling and direct cooling of a refrigerator; because of the limitation of helium resource shortage and high cost, the direct cooling magnet of the refrigerator is more and more popular in the market, but for a larger direct cooling magnet, the mass is larger, the cooling mass is also larger, the early cooling speed is slower, and the cooling time and efficiency are limited. The refrigerator has higher cooling capacity in a liquid nitrogen temperature zone, and in order to fully improve the sectional refrigerating capacity of the refrigerator, the movable self-positioning mechanical switch connected with the air cylinder is added, and the thermal switch is connected and disconnected by monitoring the temperature, so that the rapid cooling of the magnet is realized, and the cooling efficiency of the magnet is improved.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide the movable self-positioning quick cooling mechanical switch for the direct cooling magnet and the cooling method, which solve the problems of long cooling time and low cooling speed of the cooling magnet of the refrigerator, have simple installation structure and easy realization, and are suitable for quick cooling of a larger direct cooling magnet.

In order to achieve the purpose, the invention adopts the technical scheme that: the movable self-positioning rapid cooling mechanical switch for the direct cooling magnet comprises a Dewar, a cold shield, a self-positioning mechanical switch conical bowl, a self-positioning mechanical switch conical head, a heat-conducting copper strip and a magnet; the upper part of the Dewar is provided with a cylinder, a single-stage refrigerator and a double-stage refrigerator; a screw rod, a cold shield, a self-positioning mechanical switch conical bowl, a self-positioning mechanical switch conical head, a heat-conducting copper strip and a magnet are arranged below the top plate of the Dewar;

the output end of the air cylinder is connected with the magnet through the self-positioning mechanical switch conical bowl, the self-positioning mechanical switch conical head and the heat-conducting copper strip in sequence; the single-stage refrigerator is communicated with the magnet through a heat-conducting copper strip; the double-stage refrigerator is communicated with the magnet through the heat-conducting copper strip.

The double-stage refrigerator is connected with the magnet through a heat-conducting copper strip. The single-stage refrigerator is connected with the cold shield through a heat-conducting copper strip. The cylinder is connected with a self-positioning mechanical switch conical head through a corrugated pipe. The self-positioning mechanical switch conical bowl is fixed at the top of the cold shield. The self-positioning mechanical switch conical bowl and the self-positioning mechanical switch conical head have the same taper; through the connection mode, the switch can be ensured to have good heat transfer when being closed.

The magnet is arranged on an object stage at the bottom of the magnet and is suspended on the top plate of the Dewar through a screw rod. A cold screen is fixedly suspended on the top plate of the Dewar through a screw rod; and an interface flange is arranged on the top plate of the Dewar. The secondary cold head of the double-stage refrigerator is connected with the magnet through a heat-conducting copper strip; the single-stage refrigerator is also respectively connected with the self-positioning mechanical switch conical bowls through heat-conducting copper strips.

The method for quickly cooling the magnet of the movable self-positioning quick cooling mechanical switch by utilizing the direct-cooling magnet comprises the following steps of:

when the superconducting magnet is cooled, the two-stage refrigerator and the single-stage refrigerator are opened, the coil is cooled, the cylinder is ventilated, the pressure is kept to be 0.1-0.3MPa, the self-positioning mechanical switch conical bowl and the self-positioning mechanical switch conical head are closed, and the high-power single-stage refrigerator starts to cool the coil; when the coil is cooled to the lowest temperature of the single-stage refrigerator, the air source of the air cylinder is closed, the self-positioning mechanical switch conical bowl and the self-positioning mechanical switch conical head are opened, the single-stage refrigerator only cools the cold shield, and the double-stage refrigerator continues to cool the coil to the required temperature. Therefore, the movable self-positioning mechanical switch is operated, the high power of the single-stage refrigerator is fully utilized, and the time for the coil to reach the lowest temperature is accelerated.

The invention has the beneficial effects that:

in the cooling process of a large direct cooling magnet, because the whole cooling quality of the magnet is large, the cooling speed of the magnet is low, in order to realize the rapid cooling of the magnet, a movable self-positioning mechanical switch is used, the cold quantity of a liquid nitrogen temperature zone of a single-stage refrigerator is communicated with the magnet, the magnet is rapidly cooled to about 77K from the room temperature, the observation of a cooling curve shows that when the temperature curve of the magnet tends to be flat and slow at about 77K, the single-stage refrigerator cannot continuously help the magnet to further cool, at the moment, the movable self-positioning mechanical switch is disconnected, the double-stage refrigerator is used for continuously cooling to the target temperature, and the single-stage refrigerator continuously keeps the temperature gradient of the low-temperature environment of the outer.

The large direct cooling magnet has large mass and large heat energy continuing from room temperature to target temperature, so that the time for cooling the magnet to the target temperature is very long, even dozens of days, and the cooling device can well solve the problems and is verified in work.

According to the movable self-positioning mechanical switch for the large direct cooling magnet, the external cylinder switch is opened at the beginning of cooling, so that the movable self-positioning mechanical switch is closed, the refrigerating capacity of the large-refrigerating-capacity single-stage refrigerator can be directly led into the target magnet to help the magnet to be rapidly cooled, and when the temperature of the target magnet is reduced to be close to the lower limit of the temperature of the single-stage refrigerator, namely the temperature of the magnet is reduced to be lower than the temperature of liquid nitrogen, at the moment, the specific heat capacity of the material at low temperature is rapidly reduced, so that the movable self-positioning mechanical switch is only suitable for.

The self-positioning mechanical switch comprises 2 parts, wherein a self-positioning mechanical switch conical bowl is connected with an air cylinder, a self-positioning mechanical switch conical head is connected with a heat-conducting copper strip, and the self-positioning mechanical switch conical bowl and the self-positioning mechanical switch conical head are connected and disconnected through ventilation and air break of the air cylinder when the self-positioning mechanical switch conical bowl and the self-positioning mechanical switch conical head are used. Because the self-align mechanical switch awl bowl, the toper structure of self-align mechanical switch conical head have from the location function, from the location mechanical switch awl bowl with from the location mechanical switch conical head, do not need very high precision positioning, only need keep certain flexible degree of freedom, when just can guaranteeing to connect, the automatic positioning position of finding is carried out in close contact with and is connected.

The invention discloses a movable self-positioning mechanical switch device for a large direct cooling magnet, which solves the problem of low cooling speed of the large direct cooling magnet. The cooling efficiency is improved, and the structure is simple, practical and reliable, and the operation is convenient.

1) The large-scale direct-cooling magnet is quickly cooled in the early stage by fully utilizing the large-cooling capacity of the refrigerating machine in the liquid nitrogen temperature region, and the cooling efficiency of the magnet is improved.

2) The connection and disconnection of the movable self-positioning mechanical switch are realized through the connection and disconnection of an external cylinder working switch, remote operation control can be realized, and the use operation is quick and efficient.

3) By adopting the assembly structure, the magnet is convenient to mount, dismount and replace, the working efficiency is improved, and the working progress is accelerated.

Drawings

Fig. 1 is a schematic structural view of the present invention.

Fig. 2 is a top view of fig. 1 in accordance with the present invention.

In the figure, 1, an interface flange; 2. a two-stage refrigerator; 3. a support and cold shield structure; 4. a single stage refrigerator; 5. a cylinder; 6. self-positioning mechanical switch conical bowl; 7. self-positioning mechanical switch cone heads; 8. a first heat-conducting copper strip; 9. a Dewar; 10. a magnet; 11. a second heat-conducting copper strip; 12. and a third heat-conducting copper strip.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1 and 2, the movable self-positioning rapid cooling mechanical switch for the direct cooling magnet comprises a Dewar 9, a cold screen 3, a self-positioning mechanical switch conical bowl 6, a self-positioning mechanical switch conical head 7, a heat-conducting copper strip 8 and a magnet 10; the upper part of the Dewar 9 is provided with a cylinder 5, a single-stage refrigerator 4 and a double-stage refrigerator 2; a screw rod, a cold shield, a self-positioning mechanical switch conical bowl 6, a self-positioning mechanical switch conical head 7, a heat-conducting copper strip 8 and a magnet 10 are arranged below a top plate of the Dewar 9;

the output end of the air cylinder 5 is connected with a magnet 10 sequentially through a self-positioning mechanical switch conical bowl 6, a self-positioning mechanical switch conical head 7 and a heat-conducting copper strip I8; the single-stage refrigerator 4 is communicated with the magnet 10 through a second heat-conducting copper strip 11; the dual stage refrigerator 2 is in communication with the magnet 10 via a thermally conductive copper strip three 12.

The first heat-conducting copper strip 8 is the same as the second heat-conducting copper strip 11 and the third heat-conducting copper strip 12 in structure.

The double-stage refrigerator is connected with the magnet through a heat-conducting copper strip III 12.

The screw rod penetrates through the cold shield to fix the magnet below the top plate.

The magnet 10 is arranged on an object stage at the bottom of the magnet and is suspended on the top plate of the Dewar 9 through a screw rod.

And a cold screen 3 is fixedly suspended below the top plate of the Dewar 9 through a screw rod.

The secondary cold head of the double-stage refrigerator 2 is connected with a magnet 10; the single-stage refrigerator 4 is also respectively connected with the cold screen 3 and the self-positioning mechanical switch conical bowl 6 through a heat-conducting copper strip II 11.

The top plate of the Dewar 9 is fixedly suspended with the cold shield 3 through a screw rod; and an interface flange 1 is arranged on the top plate of the Dewar 9.

And a lifting ring is also arranged on the top plate of the Dewar 9.

The cold screen is fixed below the top plate through a screw rod.

The magnet is a large direct cooling magnet.

The single-stage refrigerator is connected with the cold shield through the heat-conducting copper strip device.

The cylinder is connected with a self-positioning mechanical switch conical head through a corrugated pipe, and the self-positioning mechanical switch conical head is connected with a magnet through a heat-conducting copper strip device.

The self-positioning mechanical switch conical bowl 6 is fixed at the top of the cold shield 3.

The self-positioning mechanical switch conical bowl 6 and the self-positioning mechanical switch conical head 7 have the same taper, and good matching of contact surfaces can be well guaranteed when certain pretightening force is loaded.

The magnet 10 is arranged on an object stage at the bottom of the magnet and is suspended on the top plate of the Dewar 9 through a screw rod.

The top plate of the Dewar 9 is fixedly suspended with the cold shield 3 through a screw rod; and an interface flange 1 is arranged on the top plate of the Dewar 9.

The flange interface 1 is welded with the top plate and is used for evacuating the Dewar and connecting other connectors such as signal wires.

The hanging ring is used for assembling and carrying the magnet.

The secondary cold head of the double-stage refrigerator 2 is connected with the magnet 10 through a heat-conducting copper strip III 12; the single-stage refrigerator 4 is also respectively connected with the cold screen 3 and the self-positioning mechanical switch conical bowl 6 through a heat-conducting copper strip II 11.

Under the vacuum state, in order to realize the rapid cooling of magnet 10 earlier stage, utilize from positioning mechanical switch conical bowl 6, from positioning mechanical switch conical head 7, the refrigeration capacity of single-stage refrigerator 4 directly channels into magnet 10, realize the rapid cooling of magnet, after the magnet temperature reached the temperature lower limit of single-stage refrigerator 4, namely single-stage refrigerator 4 can't continue to help the magnet 10 to cool down the back, disconnection cylinder 5 and from positioning mechanical switch conical bowl 6, from positioning mechanical switch conical head 7 continue to use doublestage refrigerator 2 to cool down magnet 10.

The operation steps of the invention are as follows:

step 1, magnet installation

The top plate Dewar roof with the support and the cold shield 3 structure and the magnet 10 and the like are hoisted by a hoisting ring and a crown block, and the whole Dewar roof is transferred into the cylinder body of the Dewar 10 after the inside is assembled in place and is sealed by a screw and a sealing ring;

step 2, rough pumping of the tank body

Vacuumizing the interior of the tank body to below 10Pa by using a mechanical vacuum pump through a tank body interface flange 1;

step 3, evacuating the tank

Firstly, a mechanical vacuum pump is used for pumping the interior of the tank body to a low vacuum 10 through a tank body interface flange 1^-1~10^-2Pa; pumped to high vacuum 10 with molecular pumps^-4Pa；

Step 4, cooling

And opening the double-stage refrigerator 2 and the single-stage refrigerator 4, opening the air cylinder 5, closing the movable self-positioning mechanical switch, closing the self-positioning mechanical switch conical bowl and the self-positioning mechanical switch conical head, and cooling the magnet 10 from room temperature 300K to about 77K of a liquid nitrogen temperature zone.

When the temperature of the magnet reaches the temperature of the liquid nitrogen temperature zone and the cooling curve is slowly reduced, the single-stage refrigerator 4 cannot further cool the magnet 10, the air cylinder 5 is disconnected at the moment, the movable self-positioning mechanical switch is disconnected, the self-positioning mechanical switch conical bowl is separated from the self-positioning mechanical switch conical head, and the double-stage refrigerator 2 continues to cool the magnet 10 to the target temperature.

The superconducting magnet is in a structure that the pull rod is hoisted and installed on the top plate, so that the problem of outgoing lines of a large number of signal lines and power lines in the magnet can be conveniently solved.

The method for quickly cooling the magnet of the movable self-positioning quick cooling mechanical switch by utilizing the direct-cooling magnet comprises the following steps of:

when the superconducting magnet is cooled, the two-stage refrigerator 2 and the single-stage refrigerator 4 are opened, the coil 10 is cooled, the air cylinder 5 is ventilated, the pressure is kept to be 0.1-0.3MPa, the self-positioning mechanical switch conical bowl 6 and the self-positioning mechanical switch conical head 7 are closed, and at the moment, the high-power single-stage refrigerator 4 starts to cool the coil 10; when the coil 10 is cooled to the lowest temperature of the single-stage refrigerator, the air source of the air cylinder is closed, the self-positioning mechanical switch conical bowl 6 and the self-positioning mechanical switch conical head 7 are opened, the single-stage refrigerator 4 only cools the cold screen 3, and the double-stage refrigerator 2 continues to cool the coil to the required temperature. Thus, by operating the movable self-positioning mechanical switch, the high power of the single-stage refrigerator 4 is fully utilized, and the time for the coil to reach the lowest temperature is accelerated.