Double-layer structure used in low-temperature Dewar

Abstract

The utility model belongs to the technical field of precision measurement, and discloses a double-layer structure used in a low-temperature Dewar. The double-layer structure used in the low-temperature Dewar comprises an outer sleeve and an inner sleeve, the outer sleeve is arranged in the low-temperature Dewar, at least part of a detection insertion rod is inserted into the inner sleeve, the detection insertion rod is used for detecting a sample, the inner sleeve is inserted into the outer sleeve and detachably connected with the outer sleeve, and refrigerants are placed in the outer sleeve and the inner sleeve. The double-layer structure is arranged in the low-temperature Dewar so as to isolate liquid helium and the detection insertion rod in the low-temperature Dewar; when a sample needs to be changed, the inner sleeve is pulled out, the detection insertion rod is reheated in the inner sleeve and does not make contact with air to generate condensate water, the outer sleeve is arranged in the low-temperature Dewar all the time, the low-temperature Dewar is in a sealed state all the time, and liquid helium in the low-temperature Dewar does not make contact with the air. By means of the double-layer structure, it is guaranteed that the detection inserting rod can stably conduct detection work, and damage to the detection inserting rod caused by sample replacement and rewarming can be prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of precision measurement, in particular to a double-layer structure for a cryogenic dewar. Background Art

[0002] Due to its characteristic of maintaining an extremely low temperature for a long time, the cryogenic dewar is widely used in various precision measurement devices to ensure the stable operation of these devices in an ultra-low temperature environment. Currently, a detection probe with an operating temperature below the liquid helium temperature range is usually inserted into a cryogenic dewar filled with liquid helium, and a single-layer cavity is usually provided to isolate the liquid helium and the detection probe.

[0003] However, the detection probe often needs to be pulled out of the cryogenic dewar for operations such as sample replacement. To prevent the influence of large-scale temperature change on the detection probe, in the prior art, one method is to first heat the low-temperature components on the detection probe for rewarming, and then directly pull out the detection probe. However, due to reasons such as uneven heating, it is easy for the component area far from the heat source to have condensed water when contacting the air, which affects the life and working conditions of the detection probe; another method is to pull out the single-layer cavity and the detection probe at the same time, which will cause the liquid helium in the cryogenic dewar to contact the air for a long time, easily resulting in helium volatilization and pollution, etc., and is not conducive to liquid helium recovery.

[0004] Therefore, it is necessary to provide a double-layer structure for a cryogenic dewar to solve the above problems. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a double-layer structure for a cryogenic dewar, which can not only ensure the stable detection work of the detection probe, but also prevent the damage to the detection probe caused by sample replacement and rewarming.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] A double-layer structure for a cryogenic dewar, comprising:

[0008] An outer sleeve, which is arranged in the cryogenic dewar;

[0009] An inner sleeve, at least part of the detection probe is inserted into the inner sleeve, the detection probe is used for detecting samples, the inner sleeve is inserted into the outer sleeve and is detachably connected to the outer sleeve, and refrigerants are placed both inside the outer sleeve and inside the inner sleeve.

[0010] Preferably, a first mounting member is arranged at the upper end of the outer sleeve, and the first mounting member is hermetically connected to the cryogenic dewar.

[0011] Preferably, a first seal is provided between the first mounting member and the cryogenic dewar, and the first seal is disposed around the outer sleeve.

[0012] Preferably, a second mounting member is provided at the upper end of the inner sleeve. The inner sleeve passes through the first mounting member and is inserted into the outer sleeve. A second seal is provided between the second mounting member and the first mounting member to seal the connection between the inner sleeve and the first mounting member.

[0013] Preferably, the inner sleeve is threadedly connected to the first mounting member.

[0014] Preferably, one of the first mounting member and the second mounting member is provided with a scale in the circumferential direction, and the other is provided with a mark. The mark cooperates with the scale to identify the screwing angle of the inner sleeve.

[0015] Preferably, a third mounting member is fixed to the upper end of the detection plug. The third mounting member is threadedly connected to the second mounting member so that the detection plug is fixedly inserted into the inner sleeve.

[0016] Preferably, the double-layer structure for the cryogenic dewar further includes:

[0017] A sealing cover fixedly connected to the third mounting member. A third seal is sleeved on the third mounting member so that the third seal is clamped between the sealing cover and the second mounting member.

[0018] Preferably, a hoop is sleeved on the third seal, and the hoop can tighten the third seal.

[0019] Preferably, the tightness of the hoop is adjustable.

[0020] Advantages of the present utility model:

[0021] The double-layer structure used in the cryogenic dewar includes an outer sleeve and an inner sleeve. The outer sleeve is arranged inside the cryogenic dewar, and at least part of the detection insertion rod is inserted into the inner sleeve. The detection insertion rod is used to detect samples. The inner sleeve is inserted into the outer sleeve and is detachably connected to the outer sleeve. Refrigerant is placed both inside the outer sleeve and inside the inner sleeve. This double-layer structure is arranged inside the cryogenic dewar to isolate the liquid helium inside the cryogenic dewar and the detection insertion rod. The refrigerant placed inside the inner sleeve and the outer sleeve can effectively transfer the low-temperature energy of the liquid helium, ensuring that the detection insertion rod can work properly in the liquid helium temperature range, preventing it from being damaged due to temperature fluctuations or affecting the detection accuracy; when a sample needs to be replaced, the inner sleeve is pulled out, so that the detection insertion rod is rewarmed inside the inner sleeve and will not come into contact with air to generate condensed water. Moreover, the outer sleeve is always arranged inside the cryogenic dewar, and the cryogenic dewar is always in a sealed state, and the liquid helium inside it will not come into contact with air. Through this double-layer structure, it not only ensures that the detection insertion rod can stably carry out detection work, but also can prevent the damage to the detection insertion rod caused by sample replacement and rewarming. Brief Description of the Drawings

[0022] Figure 1 is a schematic structural diagram of the double-layer structure used in the cryogenic dewar provided by the present utility model;

[0023] Figure 2 is a schematic structural diagram of the cooperation of the first mounting member, the second mounting member and the sealing cover provided by the present utility model;

[0024] Figure 3 is a schematic structural diagram of the cooperation of the sealing cover, the third mounting member, the hoop and the third sealing member provided by the present utility model.

[0025] In the figure:

[0026] 100, cryogenic dewar; 1001, cover plate; 10011, accommodation groove; 1002, double-layer bottle body;

[0027] 1, outer sleeve; 11, first mounting member; 111, first mounting tube; 112, first flange; 113, second flange; 114, scale;

[0028] 2, inner sleeve; 21, second mounting member; 211, second mounting tube; 212, third flange; 213, fourth flange; 214, mark;

[0029] 3, detection insertion rod; 31, third mounting member;

[0030] 4, sealing cover;

[0031] 5, hoop;

[0032] 61, first sealing member; 62, second sealing member; 63, third sealing member. Detailed Embodiment

[0033] The present utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present utility model, rather than limiting the present utility model. In addition, it should be noted that for the sake of convenience of description, only the parts related to the present utility model rather than all the structures are shown in the drawings.

[0034] In the description of the present utility model, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0035] In the present utility model, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "above the top", and "on the top" of the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below the bottom", and "under the bottom" of the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0036] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meanings.

[0037] Currently, a detection probe with an operating temperature below the liquid helium temperature range is usually inserted into a cryogenic dewar filled with liquid helium, and a single-layer cavity is usually provided to isolate the liquid helium and the detection probe. However, the detection probe often needs to be pulled out of the cryogenic dewar for operations such as sample replacement. To prevent the impact of large-scale temperature changes on the detection probe, in the prior art, one method is to first heat the low-temperature components on the detection probe for rewarming, and then directly pull out the detection probe. However, due to reasons such as uneven heating, it is easy for the component areas far from the heat source to have condensed water when contacting air, which affects the life and working conditions of the detection probe; another method is to pull out the single-layer cavity and the detection probe at the same time, which will cause the liquid helium in the cryogenic dewar to be in contact with air for a long time, easily resulting in helium volatilization and pollution, etc., and is not conducive to liquid helium recovery.

[0038] To solve the above problems, this embodiment provides a double-layer structure for a cryogenic dewar (hereinafter referred to as the double-layer structure), as Figures 1 to 3 shown. This double-layer structure includes an outer sleeve 1 and an inner sleeve 2. The outer sleeve 1 is arranged in the cryogenic dewar 100, and at least part of the detection probe 3 is inserted into the inner sleeve 2. The detection probe 3 is used to detect samples. The inner sleeve 2 is inserted into the outer sleeve 1 and is detachably connected to the outer sleeve 1. Refrigerants are placed both inside the outer sleeve 1 and inside the inner sleeve 2. By arranging this double-layer structure in the cryogenic dewar 100, the liquid helium in the cryogenic dewar 100 and the detection probe 3 are isolated. The refrigerants placed in the inner sleeve 2 and the outer sleeve 1 can effectively transfer the low-temperature energy of the liquid helium, ensuring that the detection probe 3 can work normally in the liquid helium temperature range and preventing it from being damaged or affecting the detection accuracy due to temperature fluctuations; when sample replacement is required, the inner sleeve 2 is pulled out, so that the detection probe 3 is rewarmed inside the inner sleeve 2 and will not contact air to generate condensed water. Moreover, the outer sleeve 1 is always arranged in the cryogenic dewar 100, and the cryogenic dewar 100 is always in a sealed state, and the liquid helium inside it will not contact air. Through this double-layer structure, both the stable detection work of the detection probe 3 can be ensured, and the damage caused by sample replacement and rewarming to the detection probe 3 can be prevented.

[0039] Specifically, as Figures 1 to 3 shown, a first mounting member 11 is provided at the upper end of the outer sleeve 1, and the first mounting member 11 is hermetically connected to the cryogenic dewar 100. By installing the outer sleeve 1 into the cryogenic dewar 100 through the first mounting member 11, the good sealing performance of the cryogenic dewar 100 can be ensured, and the liquid nitrogen inside it will not contact the outside air. Specifically, the cryogenic dewar 100 includes a double-layer bottle body 1002 and a cover plate 1001. An opening for inserting the outer sleeve 1 is provided on the cover plate 1001. After the outer sleeve 1 is inserted into the cryogenic dewar 100, the first mounting member 11 is located outside the cryogenic dewar 100, and the first mounting member 11 can be hermetically connected to the cover plate 1001.

[0040] In this embodiment, as Figure 1, Figure 2 As shown in Figure 2 , a first seal 61 is clamped between the first mounting member 11 and the cryogenic dewar 100. The first seal 61 surrounds the outer sleeve 1. The first seal 61 can isolate the outside air from entering the interior of the cryogenic dewar 100 and prevent the liquid nitrogen from contacting the air and causing pollution.

[0041] Furthermore, as Figure 1 , Figure 2 shown, the cryogenic dewar 100 is provided with a receiving groove 10011, and the first seal 61 is received in the receiving groove 10011. The receiving groove 10011 provides an accurate installation position for the first seal 61, ensuring that the first seal 61 can accurately fit between the cryogenic dewar 100 and the first mounting member 11, thereby improving the overall sealing effect. Specifically, the receiving groove 10011 is provided on the cover plate 1001 of the cryogenic dewar 100.

[0042] In this embodiment, as Figure 1 , Figure 2 shown, the first mounting member 11 includes a first mounting pipe 111 and a first flange 112 and a second flange 113 respectively provided at both ends of the first mounting pipe 111. The first mounting pipe 111 is communicated with the outer sleeve 1. The first flange 112 abuts against the cover plate 1001, and the first seal 61 is clamped between the first flange 112 and the cover plate 1001.

[0043] Specifically, as Figure 1 , Figure 2 shown, a second mounting member 21 is provided at the upper end of the inner sleeve 2. The inner sleeve 2 passes through the first mounting member 11 and is inserted into the outer sleeve 1. A second seal 62 is clamped between the second mounting member 21 and the first mounting member 11 to enable a sealed connection between the inner sleeve 2 and the first mounting member 11. By providing the second seal 62, the airtightness inside the outer sleeve 1 is ensured, preventing the refrigerant contained in the outer sleeve 1 from leaking, and preventing the cooling efficiency from changing due to refrigerant leakage, thereby avoiding the situation of affecting the test results.

[0044] Specifically, the inner sleeve 2 is threadedly connected to the first mounting member 11. Threaded connection is a simple and reliable connection method, which allows for quick installation and disassembly by rotating the inner sleeve 2. In the scenario of this embodiment where the inner sleeve 2 needs to be frequently disassembled and assembled, the operation is made more convenient and fast; by adjusting the degree of screwing of the inner sleeve 2, the distance between the first mounting member 11 and the second mounting member 21 can be adjusted, that is, the clamping pressure received by the second seal 62 can be adjusted, preventing the second seal 62 from being damaged due to being clamped too tightly or having insufficient sealing due to being clamped too loosely.

[0045] Furthermore, as Figure 1 , Figure 2As shown, one of the first mounting member 11 and the second mounting member 21 is provided with a scale 114 circumferentially, and the other is provided with a mark 214. The mark 214 and the scale 114 cooperate to identify the screwing angle of the inner sleeve 2. By providing the scale 114 and the mark 214 on the first mounting member 11 and the second mounting member 21, precise quantitative control of the screwing angle of the inner sleeve 2 is achieved, which helps to maintain a consistent tightening degree during the disassembly and assembly process, and avoids the problems of insufficient tightening or over-tightening caused by human factors. As the second seal 62 wears and fatigues during use, its sealing performance will gradually decline. By gradually increasing the degree of thread fit between the inner sleeve 2 and the first mounting member 11, the clamping pressure on the second seal 62 can be increased, thereby effectively compensating for the wear of the second seal 62, maintaining the overall sealing performance, and extending the service life of the second seal 62.

[0046] Exemplarily, for a new second seal 62, during the first N disassembly and assembly operations, the inner sleeve 2 is screwed by an angle of a; during the (N + 1)-th to 2N-th disassembly and assembly operations, the inner sleeve 2 is screwed by an angle of a + x; during the (2N + 1)-th to 3N-th disassembly and assembly operations, the inner sleeve 2 is screwed by an angle of a + 2x, and so on, where N is a positive integer.

[0047] In an alternative embodiment, the first mounting member 11 is provided with a scale 114 circumferentially, and the second mounting member 21 is provided with a mark 214. In another alternative embodiment, the second mounting member 21 is provided with a scale 114 circumferentially, and the first mounting member 11 is provided with a mark 214. It can be understood that the scale 114 and the mark 214 are arranged according to actual requirements, and this embodiment is not limited.

[0048] In this embodiment, as Figure 1 、 Figure 2 shown, the second mounting member 21 includes a second mounting tube 211 and a third flange 212 and a fourth flange 213 respectively arranged at both ends of the second mounting tube 211. A second mounting member 21 is clamped between the third flange 212 and the second flange 113. Specifically, one of the second flange 113 and the third flange 212 is provided with a scale 114, and the other is provided with a mark 214.

[0049] Specifically, a third mounting member 31 is fixed to the upper end of the detection plug 3. The third mounting member 31 is threadedly connected to the second mounting member 21 so that the detection plug 3 is fixedly inserted into the inner sleeve 2. When replacing the sample, it is necessary to take out the detection plug 3 from the inner sleeve 2. By means of threaded fixation, the disassembly and assembly of the detection plug 3 are made simpler and quicker.

[0050] Specifically, as Figure 1As shown, this double-layer structure further includes a sealing cover 4. The sealing cover 4 is fixedly connected to the third mounting member 31. A third sealing member 63 is sleeved on the third mounting member 31, so that the third sealing member 63 is clamped between the sealing cover 4 and the second mounting member 21. By providing the sealing cover 4 and the third sealing member 63, the airtightness inside the inner sleeve 2 is ensured, preventing the refrigerant contained in the inner sleeve 2 from leaking, and preventing the cooling efficiency from changing due to refrigerant leakage, thereby avoiding the situation that affects the test results.

[0051] In this embodiment, as Figure 2 、 Figure 3 shown, the sealing cover 4 includes a fixing portion (not shown in the figure). A fifth flange is provided below the fixing portion. Bolts are passed through the fixing portion and the third mounting member 31 to fixedly connect the sealing cover 4 and the third mounting member 31. At this time, the fifth flange and the fourth flange 213 jointly clamp the third sealing member 63 to ensure the sealing performance.

[0052] Furthermore, as Figure 3 shown, a hoop 5 is sleeved on the third sealing member 63, and the hoop 5 can tighten the third sealing member 63. The third sealing member 63 can be fixed by the hoop 5, so that the third sealing member 63 will not fall off when the test plug 3 is disassembled and assembled.

[0053] In this embodiment, the tightness of the hoop 5 is adjustable. By adjusting the tightness of the hoop 5, the clamping pressure on the third sealing member 63 can be adjusted, thereby effectively compensating for the wear of the third sealing member 63, maintaining the overall sealing performance, and extending the service life of the third sealing member 63. Specifically, the two ends of the hoop 5 are connected by adjusting studs, and the tightness of the hoop 5 is adjusted by screwing the adjusting studs.

[0054] Obviously, the above embodiments of the present invention are only examples for clearly explaining the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A double-layer structure for a cryogenic dewar, characterized in that, Comprising: An outer sleeve (1), the outer sleeve (1) being disposed within a cryogenic dewar (100); An inner sleeve (2), a detection plunger (3) being at least partially inserted within the inner sleeve (2), the detection plunger (3) being used to detect a sample, the inner sleeve (2) being inserted within the outer sleeve (1) and detachably connected to the outer sleeve (1), and a refrigerant being placed within both the outer sleeve (1) and the inner sleeve (2).

2. The double-layer structure for a cryogenic dewar according to claim 1, characterized in that, A first mounting member (11) is provided at the upper end of the outer sleeve (1), and the first mounting member (11) is hermetically connected to the cryogenic dewar (100).

3. The double-layer structure for a cryogenic dewar according to claim 2, wherein, A first seal (61) is interposed between the first mounting member (11) and the cryogenic dewar (100), and the first seal (61) is disposed around the outer sleeve (1).

4. The double-layer structure for a cryogenic dewar according to claim 2, characterized in that, A second mounting member (21) is provided at the upper end of the inner sleeve (2), the inner sleeve (2) passes through the first mounting member (11) and is inserted within the outer sleeve (1), and a second seal (62) is interposed between the second mounting member (21) and the first mounting member (11) such that the inner sleeve (2) is hermetically connected to the first mounting member (11).

5. The double-layer structure for a cryogenic dewar according to claim 4, characterized in that, The inner sleeve (2) is threadedly connected to the first mounting member (11).

6. The double-layer structure for a cryogenic dewar according to claim 5, characterized in that, One of the first mounting member (11) and the second mounting member (21) is provided with a scale (114) circumferentially, and the other is provided with a mark (214), and the mark (214) cooperates with the scale (114) to identify the screwing angle of the inner sleeve (2).

7. The double-layer structure for a cryogenic dewar according to claim 4, characterized in that, A third mounting member (31) is fixed to the upper end of the detection plunger (3), and the third mounting member (31) is threadedly connected to the second mounting member (21) such that the detection plunger (3) is fixedly inserted within the inner sleeve (2).

8. The double-layer structure for a cryogenic dewar according to claim 7, characterized in that, The double-layer structure for a cryogenic dewar further comprises: A sealing cover (4), the sealing cover (4) being fixedly connected to the third mounting member (31), and a third seal (63) being sleeved on the third mounting member (31) such that the third seal (63) is interposed between the sealing cover (4) and the second mounting member (21).

9. The double-layer structure for a cryogenic dewar according to claim 8, characterized in that, A hoop (5) is sleeved outside the third seal (63), and the hoop (5) can tighten the third seal (63).

10. The double-layer structure for a cryogenic dewar according to claim 9, characterized in that, The tightness degree of the hoop (5) is adjustable.

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