Ultralow-vibration liquid-helium-free dilution refrigerating machine
Through the triple shock absorption structure design, the vibration level of the dilution refrigerator is reduced, and the problem of large vibration of the traditional dilution refrigerator is solved, and a compact low vibration and efficient mK-level low temperature environment is achieved, which avoids the continuous consumption of liquid helium.
Patent Information
- Application Number
- CN202420334053.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-22
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2034-02-22
AI Technical Summary
The vibration generated during operation of traditional dilution refrigerators causes interference to extreme environmental testing. The existing shock absorption design cannot effectively reduce vibration and takes up a large space.
It adopts a triple shock absorbing structure design, including first-stage, second-stage and third-stage shock absorbing components, which are linked by corrugated pipes and fixed rods, combined with vacuum adjustment of the air outlet to minimize the vibration of the cold head of the refrigerator.
Reducing vibration levels from the order of microns to 20nm achieves a compact low vibration design that maintains mK-level low temperature environment without the need for continuous consumption of liquid helium, and the bellows design ensures sealing and long life.
Smart Images
Figure CN222230988U_ABST
Abstract
Description
Technical Field
[0001] The utility model discloses an ultra-low vibration liquid-helium-free dilution refrigerator, belonging to the field of ultra-low temperature testing devices. Background Art
[0002] The dilution refrigerator uses the phase separation property of helium-3 and helium-4 mixed gases after liquefaction to achieve extremely low temperatures. Traditional dilution refrigerators use liquid helium to liquefy helium-3 and helium-4 mixed gases. In order to make the system work stably for a long time, the amount of liquid helium required is very large. With the shortage of helium resources, the operation and maintenance costs of this dilution refrigerator are getting higher and higher, and it is no longer suitable for the growing scientific research needs.
[0003] With the advancement of technology, dilution refrigerators that use refrigerators as cold sources only need to consume electricity to provide mK-level low temperatures, which can also meet scientific research requirements to a large extent. Commonly used refrigerators are Gifford-McMahon (GM) refrigerators and Pulse-Tube (PT) refrigerators. However, their working principles determine that there are um-level vibrations in their operation. For extreme environment tests, such as weak signal measurement, quantum dot measurement, gravitational wave detection, scanning tunneling microscopy and other fields, this level of vibration is unbearable. How to reduce or avoid the impact of vibration on the above experimental fields is critical.
[0004] Previously, in order to reduce the vibration of the cold head, the prior art, such as the dilution refrigeration system disclosed in CN202210484998.1, has a small low-temperature refrigerator suspended, and the small low-temperature refrigerator has no contact with the inner wall of the shock-absorbing heat exchange cavity. At the same time, the bellows also has the function of isolating vibration, thereby minimizing the vibration transmitted from the small low-temperature refrigerator to the cold box, avoiding the increase in the minimum temperature of the system caused by the heat input caused by the vibration, and enabling the system to achieve excellent performance far below 1 micron vibration. This kind of shock-absorbing design can only slow down the vibration to a certain extent. Since it does not take into account the influence of the cold head's own weight and atmospheric pressure on the vibration, its shock-absorbing effect is relatively poor, and the presence of the bracket occupies a large space.
[0005] In view of the shortcomings of the prior art, the purpose of the utility model is to provide an ultra-low vibration liquid helium-free dilution refrigerator. Through the triple shock-absorbing structure design, the vibration of the refrigerator cold head during operation is reduced to the nanometer level, solving the problem of large vibration of the dilution refrigerator using the refrigerator as the cold source. Utility Model Content
[0006] In view of the deficiencies in the prior art, the utility model aims to provide an ultra-low vibration liquid helium-free dilution refrigerator.
[0007] In order to achieve the above purpose, the utility model is implemented through the following technical solutions:
[0008] An ultra-low vibration liquid helium-free dilution refrigerator comprises a damping mechanism, a refrigerator and a dilution refrigerator main chamber, wherein the damping mechanism, the refrigerator and the dilution refrigerator main chamber are arranged in sequence from top to bottom, wherein:
[0009] The refrigerator is composed of a refrigerator cold head and a driving motor;
[0010] The refrigerator cold head is embedded in the shock absorbing mechanism;
[0011] The shock absorbing mechanism is composed of a primary shock absorbing assembly, a secondary shock absorbing assembly and a tertiary shock absorbing assembly. The shock absorbing mechanism is installed on the top of the main cavity of the dilution refrigerator through a mainboard flange.
[0012] Furthermore, the first-level shock absorbing assembly includes a first-level movable plate, a first-level bellows and a first-level fixed plate, the first-level fixed plate is fixed on the main board flange, the main board flange is fixed on the top of the dilution refrigerator main chamber, the first-level bellows is provided on the top of the first-level fixed plate, the first-level bellows is provided on the top of the first-level movable plate, and the refrigerator cold head is arranged on the first-level movable plate.
[0013] Furthermore, the first-stage movable plate, the first-stage bellows and the first-stage fixed plate form a closed cavity, the closed cavity is connected to the main cavity of the dilution refrigerator, and an air extraction port is provided on the mainboard flange.
[0014] Furthermore, the secondary shock absorbing assembly includes a secondary fixed plate, a secondary bellows, a secondary movable plate and a second air suction port, the secondary fixed plate is provided at the bottom of the secondary bellows, and the secondary movable plate is provided at the bottom of the secondary bellows.
[0015] Furthermore, the secondary fixed plate, the secondary bellows and the secondary movable plate together form a second closed cavity, and the second air suction port is arranged on the secondary fixed plate.
[0016] Furthermore, the secondary fixed plate is connected to the main board flange via a fixing rod 1, the fixing rod 1 penetrates the secondary movable plate, and the primary movable plate and the secondary movable plate are connected via a linkage rod 1.
[0017] Furthermore, two clamping blocks are symmetrically fixed on an outer surface of the fixing rod, and the upper and lower clamping blocks are respectively located on the upper and lower sides of the secondary movable plate.
[0018] Furthermore, the three-stage shock-absorbing assembly includes a three-stage fixed plate, a three-stage bellows, a three-stage movable plate and an air suction port. The three-stage bellows is provided at the bottom of the three-stage fixed plate, and the three-stage movable plate is provided at the bottom of the three-stage bellows.
[0019] Furthermore, the three-stage fixed plate, the three-stage bellows and the three-stage movable plate form a three-stage closed cavity, and a three-stage air extraction port is provided on the top of the three-stage fixed plate.
[0020] Furthermore, the third-level fixed plate and the second-level fixed plate are connected and fixed by a second fixing rod, and the third-level movable plate and the second-level movable plate are connected by a second linkage rod.
[0021] Beneficial effects of the utility model:
[0022] The utility model introduces a triple shock-absorbing component design to minimize the effects of atmospheric pressure and the gravity of the refrigerator cold head on the main chamber of the dilution refrigerator, thereby reducing the vibration level of the entire system from the micron level to 20nm. The system has a compact structure and extremely low vibration, and can maintain a mK-level low-temperature environment without continuous consumption of liquid helium when the system is working.
[0023] In addition, the utility model designs the primary bellows, the secondary bellows and the tertiary bellows as welded bellows, so that the bellows have the characteristics of good sealing, large deformation and long service life, and can avoid aging due to long-term use, poor airtightness and even pollution of the dilution refrigerator cavity.
[0024] In addition, the design of the triple damping assembly in the utility model can basically eliminate the influence of atmospheric pressure and the vibration generated when the refrigerator cold head is working on the dilution refrigerator main chamber. The upper and lower clamping blocks can be used to limit the movement range of the secondary moving plate, so that when the refrigerator cold head and the secondary damping assembly reciprocate up and down together, the upper and lower clamping blocks can limit the movement range of the refrigerator head, and during transportation, the upper and lower clamping blocks can be used to fix and support the cold head and protect the three sets of damping assemblies.
[0025] In addition, the fixed rod 1 in the utility model can install the secondary fixed plate on the main board flange, so as to support the secondary shock-absorbing assembly; the linkage rod 1 can connect the secondary shock-absorbing assembly with the primary shock-absorbing assembly; and connect the secondary movable plate with the primary movable plate, so that when the cold head of the refrigerator is working, the secondary bellows and the secondary movable plate reciprocate up and down together with the linkage rod 1 and the primary movable plate of the primary shock-absorbing assembly; the fixed rod 2 can support the tertiary shock-absorbing assembly; the linkage rod 2 can connect the tertiary shock-absorbing assembly with the secondary shock-absorbing assembly, so as to cause the tertiary bellows and the tertiary movable plate to reciprocate up and down together with the linkage rod 2 and the secondary movable plate of the secondary shock-absorbing assembly.
[0026] In addition, for the shock-absorbing assembly in the utility model, the secondary shock-absorbing assembly can be used to offset most of the force exerted by the cold head weight of the refrigerator and the atmospheric pressure after vacuuming on the primary shock-absorbing assembly; and the tertiary shock-absorbing assembly can serve as an auxiliary to the secondary shock-absorbing assembly to further completely offset the force exerted by the cold head weight of the refrigerator and the atmospheric pressure after vacuuming on the primary shock-absorbing assembly. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0028] Figure 1 This is a schematic diagram of the overall structure of an ultra-low vibration liquid helium-free dilution refrigerator of the utility model;
[0029] Figure 2 This is a schematic diagram of the structure of a vibration reduction mechanism of an ultra-low vibration liquid helium-free dilution refrigerator of the utility model;
[0030] In the figure, 1. shock absorbing mechanism; 2. refrigerator; 201. refrigerator cold head; 202. drive motor; 3. dilution refrigerator main chamber; 4. main board flange; 5. exhaust port one; 6. primary shock absorbing assembly; 601. primary moving plate; 602. primary bellows; 603. primary fixed plate; 7. secondary shock absorbing assembly; 701. secondary fixed plate; 702. secondary bellows; 703. secondary moving plate; 704. exhaust port two; 8. tertiary shock absorbing assembly; 801. tertiary fixed plate; 802. tertiary bellows; 803. tertiary moving plate; 804. exhaust port three; 9. fixed rod one; 10. linkage rod one; 11. fixed rod two; 12. linkage rod two; 13. block. DETAILED DESCRIPTION
[0031] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0032] See also Figure 1-2The utility model provides a technical solution for an ultra-low vibration liquid helium-free dilution refrigerator, an ultra-low vibration liquid helium-free dilution refrigerator, comprising a damping mechanism 1, a refrigerator 2 and a dilution refrigerator main chamber 3, wherein the damping mechanism 1, the refrigerator 2 and the dilution refrigerator main chamber 3 are arranged in sequence from top to bottom, wherein: the refrigerator 2 is composed of a refrigerator cold head 201 and a driving motor 202; the refrigerator cold head 201 is embedded in the damping mechanism 1; the damping mechanism 1 is composed of a primary damping component 6, a secondary damping component 7 and a tertiary damping component 8, and the damping mechanism 1 is installed on the top of the dilution refrigerator main chamber 3 through a mainboard flange 4.
[0033] See also Figure 2 The primary damping assembly 6 comprises a primary moving plate 601, a primary bellows 602 and a primary fixing plate 603, wherein the primary fixing plate 603 is fixed on the main board flange 4, and the main board flange 4 is fixed on the top of the dilution refrigerator main chamber 3, the primary bellows 602 is arranged on the top of the primary fixing plate 603, the primary moving plate 601 is arranged on the top of the primary bellows 602, the refrigerator cold head 201 extends to the inside of the dilution refrigerator main chamber 3 through the primary bellows 602, and the refrigerator cold head 201 is arranged on the primary moving plate 601, the primary moving plate 601, the primary bellows 602 and the primary fixing plate 603 form a closed cavity 1, and the closed cavity 1 is communicated with the dilution refrigerator main chamber 3, and an air suction port 15 is arranged on the main board flange 4, and the dilution refrigerator main chamber 3 and the primary damping assembly 6 are evacuated through the air suction port 15.
[0034] See also Figure 2 The secondary shock absorbing component 7 includes a secondary fixed plate 701, a secondary bellows 702, a secondary movable plate 703 and a second air suction port 704. The secondary fixed plate 701 is provided with the secondary bellows 702 at the bottom, and the secondary movable plate 703 is provided with the secondary bellows 702 at the bottom. The secondary fixed plate 701, the secondary bellows 702 and the secondary movable plate 703 form a second closed cavity. The second air suction port 704 is provided on the secondary fixed plate 701, and the secondary shock absorbing component 7 is vacuumed through the second air suction port 704.
[0035] See also Figure 2 The secondary fixed plate 701 is connected to the main board flange 4 through a fixing rod 9, and the fixing rod 9 penetrates the secondary movable plate 703. The primary movable plate 601 and the secondary movable plate 703 are connected through a linkage rod 10. Two blocks 13 are symmetrically fixed on the outer surface of the fixing rod 9. The upper and lower blocks 13 are respectively located on the upper and lower sides of the secondary movable plate 703.
[0036] For the secondary shock absorbing assembly 7, the secondary fixed plate 701 is installed on the main board flange 4 through a fixing rod 9, which plays a role in supporting the secondary shock absorbing assembly 7, and the secondary shock absorbing assembly 7 is connected to the primary shock absorbing assembly 6 through a linkage rod 10; when the refrigerator cold head 201 is working, the secondary bellows 702 and the secondary movable plate 703 reciprocate up and down together with the linkage rod 10 and the primary movable plate 601 of the primary shock absorbing assembly 6; the secondary shock absorbing assembly 7 is used to offset most of the self-weight of the refrigerator cold head 201 and the force of the atmospheric pressure after vacuuming on the primary shock absorbing assembly 6.
[0037] See also Figure 2 The three-stage shock absorbing assembly 8 comprises a three-stage fixed plate 801, a three-stage bellows 802, a three-stage movable plate 803 and a third air suction port 804. The three-stage fixed plate 801 is provided with the three-stage bellows 802 at the bottom, and the three-stage movable plate 803 is provided at the bottom of the three-stage bellows 802. The three-stage fixed plate 801, the three-stage bellows 802 and the three-stage movable plate 803 form a closed cavity three. The top of the three-stage fixed plate 801 is provided with a third air suction port 804, and the three-stage shock absorbing assembly 8 is vacuumed through the third air suction port 804.
[0038] For the tertiary shock absorbing assembly 8, the tertiary fixed plate 801 is installed on the secondary fixed plate 701 through the fixing rod 2 11, which supports the tertiary shock absorbing assembly 8, and the tertiary shock absorbing assembly 8 is connected with the secondary shock absorbing assembly 7 through the linkage rod 2 12; the tertiary bellows 802 and the tertiary movable plate 803 reciprocate up and down with the linkage rod 2 12 and the secondary movable plate 1 703 of the secondary shock absorbing assembly 7; the tertiary shock absorbing assembly 8 serves as an auxiliary of the secondary shock absorbing assembly 7, further completely offsetting the force of the cold head 201 of the refrigerator and the atmospheric pressure after vacuuming on the primary shock absorbing assembly 6.
[0039] The primary bellows 602 and the secondary bellows 702 are consistent in shape and size, and the diameter of the tertiary bellows 802 is smaller than that of the secondary bellows 702; the primary bellows 602, the secondary bellows 702 and the tertiary bellows 802 are all welded bellows. Traditional bellows use rubber bellows, which will age and deteriorate in air tightness after long-term use, and may even pollute the dilution refrigerator cavity. The welded bellows have the characteristics of good sealing, large deformation and long service life.
[0040] See also Figure 2 The third-level fixed plate 801 and the second-level fixed plate 701 are connected and fixed by a second fixing rod 11, and the third-level movable plate 803 and the second-level movable plate 703 are connected by a second linkage rod 12;
[0041] The number of both the fixed rod 1 9 and the linkage rod 1 10 is four, the number of both the fixed rod 2 11 and the linkage rod 2 12 is two, and the fixed rod 1 9, the linkage rod 1 10, the fixed rod 2 11 and the linkage rod 2 12 are all stainless steel columns, which have good anti-deformation effect;
[0042] The fixing rod 9 is arranged through the secondary movable plate 703, and two clamping blocks 13 are installed on each fixing rod 9, respectively at the upper and lower sides of the secondary movable plate 703. During operation, the cold head 201 of the refrigerator reciprocates up and down together with the secondary damping assembly 7. At this time, the upper and lower clamping blocks 13 can limit the movement range of the secondary movable plate 703, and the cold head can be fixedly supported by the clamping blocks 13 and the three groups of damping assemblies 8 can be protected during transportation.
[0043] The design of the triple damping assembly 8 can substantially eliminate the influence of the atmospheric pressure and the vibration generated when the refrigerator cold head 201 is working on the dilution refrigerator main chamber 3 .
[0044] The refrigerator 2 is generally selected as a pulse tube refrigerator, including a refrigerator cold head 201 and a drive motor 202. The refrigerator 2 provides cooling capacity for the entire dilution refrigerator system. The dilution refrigerator main chamber 3 uses the cooling capacity of the refrigerator to liquefy the helium 3 and helium 4 inside and make them phase separate to achieve mK-level low temperature.
[0045] When the device is working, first loosen the block 13 and preliminarily adjust the position of the block 13 to ensure that the movement range of the refrigerator cold head 201 is not affected during operation;
[0046] Secondly, the main chamber 3 of the dilution refrigerator and the first-stage damping assembly 6 are evacuated through the suction port 15. The first-stage damping assembly 6 will shrink downward under the action of the refrigerator cold head 201 and the atmospheric pressure. -4 mbar, stop pumping;
[0047] Then, the state of the primary bellows 602 is preliminarily adjusted by using the secondary shock absorbing assembly 7, specifically, the secondary shock absorbing assembly 7 is vacuumed through the second suction port 704. As the vacuum degree of the secondary shock absorbing assembly 7 decreases, the secondary moving plate 703 will move the primary moving plate 601 and the cold head 201 of the refrigerator upward. When the primary bellows 602 preliminarily reaches a natural state, the pumping is stopped;
[0048] Then, use the three-stage damping assembly 8 to accurately adjust the state of the primary bellows 602, and pump the third suction port 804 to evacuate the three-stage damping assembly 8. At this time, the three-stage moving plate 803 will continue to move slightly upward with the secondary moving plate 703, the primary moving plate 601 and the refrigerator cold head 201. When the primary bellows 602 reaches a natural state, stop pumping. Adjust the position of the block 13 so that it is about 2 cm away from the secondary moving plate 703;
[0049] At this point, the influence of the refrigerator cold head 201 and atmospheric pressure on the primary bellows 602 has been basically eliminated. After starting the refrigerator 2, the vibration level transmitted to the dilution refrigerator main chamber 3 will be reduced to about 20nm. Finally, under the action of the refrigerator 2, the dilution refrigerator reaches a low temperature of mK level.
[0050] Although this specification is described according to implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.
Claims
1. An ultra-low vibration liquid helium-free dilution refrigerator, characterized in that: The invention comprises a damping mechanism (1), a refrigerator (2) and a dilution refrigerator main chamber (3), wherein the damping mechanism (1), the refrigerator (2) and the dilution refrigerator main chamber (3) are arranged in sequence from top to bottom, wherein: The refrigerator (2) is composed of a refrigerator cold head (201) and a drive motor (202); The refrigerator cold head (201) is embedded in the shock absorbing mechanism (1); The shock absorbing mechanism (1) is composed of a primary shock absorbing assembly (6), a secondary shock absorbing assembly (7) and a tertiary shock absorbing assembly (8). The shock absorbing mechanism (1) is installed on the top of the main chamber (3) of the dilution refrigerator via a mainboard flange (4).
2. The ultra-low vibration liquid helium-free dilution refrigerator according to claim 1, characterized in that: The primary damping assembly (6) comprises a primary movable plate (601), a primary bellows (602) and a primary fixed plate (603); the primary fixed plate (603) is fixed on the main board flange (4); the main board flange (4) is fixed on the top of the dilution refrigerator main chamber (3); the primary bellows (602) is arranged on the top of the primary fixed plate (603); the primary movable plate (601) is arranged on the top of the primary bellows (602); and the refrigerator cold head (201) is arranged on the primary movable plate (601).
3. The ultra-low vibration liquid helium-free dilution refrigerator according to claim 2, characterized in that: The first-stage movable plate (601), the first-stage bellows (602) and the first-stage fixed plate (603) form a closed cavity one, the closed cavity one is connected to the dilution refrigerator main cavity (3), and the mainboard flange (4) is provided with an air extraction port one (5).
4. The ultra-low vibration liquid helium-free dilution refrigerator according to claim 3, characterized in that: The secondary shock absorbing assembly (7) comprises a secondary fixed plate (701), a secondary bellows (702), a secondary movable plate (703) and a second air suction port (704); the secondary bellows (702) is provided at the bottom of the secondary fixed plate (701), and the secondary movable plate (703) is provided at the bottom of the secondary bellows (702).
5. The ultra-low vibration liquid helium-free dilution refrigerator according to claim 4, characterized in that: The secondary fixed plate (701), the secondary bellows (702) and the secondary movable plate (703) together form a closed cavity body 2, and the second air suction port (704) is arranged on the secondary fixed plate (701).
6. The ultra-low vibration liquid helium-free dilution refrigerator according to claim 4, characterized in that: The secondary fixed plate (701) is connected to the main plate flange (4) via a fixing rod (9), the fixing rod (9) passes through the secondary movable plate (703), and the primary movable plate (601) and the secondary movable plate (703) are connected via a linkage rod (10).
7. The ultra-low vibration liquid helium-free dilution refrigerator according to claim 6, characterized in that: Two clamping blocks (13) are symmetrically fixed on the outer surface of the fixing rod (9), and the upper and lower clamping blocks (13) are respectively located on the upper and lower sides of the secondary movable plate (703).
8. The ultra-low vibration liquid helium-free dilution refrigerator according to claim 4, characterized in that: The three-stage shock absorbing assembly (8) comprises a three-stage fixed plate (801), a three-stage bellows (802), a three-stage movable plate (803) and a third air suction port (804); the three-stage bellows (802) is provided at the bottom of the three-stage fixed plate (801), and the three-stage movable plate (803) is provided at the bottom of the three-stage bellows (802).
9. The ultra-low vibration liquid helium-free dilution refrigerator according to claim 8, characterized in that: The three-stage fixed plate (801), the three-stage bellows (802) and the three-stage movable plate (803) form a closed cavity three, and a third air suction port (804) is provided on the top of the three-stage fixed plate (801).
10. The ultra-low vibration liquid helium-free dilution refrigerator according to claim 8, characterized in that: The third-level fixed plate (801) and the second-level fixed plate (701) are connected and fixed via a second fixing rod (11), and the third-level movable plate (803) and the second-level movable plate (703) are connected via a second linkage rod (12).