Heat exchanger for dilution refrigerator, manufacturing method and dilution refrigerator

Abstract

The invention provides a heat exchanger for a dilution refrigerator, a manufacturing method and the dilution refrigerator, and relates to the technical field of dilution refrigerators. The heat exchanger comprises a plurality of heat exchange single bodies which are sequentially communicated, and each heat exchange single body comprises a heat conduction piece, two cover bodies and a filling body. The two cover bodies are arranged on the two sides of the heat conduction piece in a covering mode respectively to define a first cavity and a second cavity, the first cavity is internally provided with a flowing 3He solution, the second cavity is internally provided with a flowing mixed solution of the 3He solution and a 4He solution, and therefore the 3He solution and the mixed solution exchange heat through the heat conduction piece. The filling body is arranged in the first cavity and the second cavity, and a first hole system is formed in the filling body and is suitable for increasing the heat exchange area of the 3He solution and the mixed solution. And a second hole system is further formed in the filling body and is suitable for increasing the penetration depth of the 3He solution and the mixed solution into the filling body while increasing the heat exchange area.

Description

Technical Field

[0001] This invention relates to the field of heat exchange and dilution refrigeration technology, and more specifically, to a heat exchanger for a dilution refrigeration machine, a manufacturing method thereof, and a dilution refrigeration machine. Background Technology

[0002] Dilution refrigerators are indispensable core equipment in the field of cryogenic experimental physics, with operating temperatures down to the milliKelvin (mK) level. At extremely low temperatures (such as typically below 0.87 K), they are used in cryogenic environments. 3 He- 4 He mixtures will undergo phase separation, forming a mixture rich in... 3 He condensate and rich in 4 He's diluted phase. The dilution refrigeration cycle continuously dilutes the concentrated phase... 3 Cooling is achieved by dissolving He atoms into the dilute phase. This process requires heat absorption because the transfer of He atoms from the high-potential condensed phase to the low-potential dilute phase is endothermic, similar to liquid evaporation. A circulating system is designed to continuously extract gaseous He atoms from the dilute phase using a vacuum pump. 3 After purification and condensation, He is re-injected into the concentrated phase, ultimately establishing and maintaining a stable milliKelvin-level ultra-low temperature environment in the mixing chamber.

[0003] Within a dilution refrigeration unit, the performance of the heat exchanger is the core factor determining whether millikelvin temperatures can ultimately be achieved. Its function is to exchange heat for the higher temperatures in the return cycle. 3 He solution at lower temperatures 3 He- 4 Efficient heat exchange between the liquids significantly reduces the load on subsequent refrigeration stages. If the heat exchanger is inefficient, the returned heat flow will result in significant heat loss, preventing the refrigeration cycle from establishing the required extremely low temperature environment. Therefore, the design of heat exchangers in dilution refrigerators faces stringent requirements, striving for near-ideal thermal efficiency (typically exceeding 99%). To achieve this, a compact counter-flow design with a large surface area is often employed, and high thermal conductivity materials such as oxygen-free copper, which exhibit excellent thermal conductivity at extremely low temperatures, are selected to ensure efficient heat transfer even with small temperature differences.

[0004] In related technologies, sintered nano-silver bodies are typically used inside heat exchangers to increase the heat exchange area because their porous structure provides a large surface area, and metallic silver itself has good thermal conductivity. However, some drawbacks still exist, such as... 3 He solution, 3 He- 4The limited permeability of the helium-containing mixture restricts the thickness of the sintered body. This means that further increasing the heat exchange area can only be achieved by increasing the bottom area of ​​the sintered body, thereby expanding its volume. However, this increases the horizontal space required, affecting the arrangement of other structures near the cold plate, and significantly increases the amount of helium used, leading to higher costs. Therefore, providing a heat exchanger that addresses these shortcomings has become a pressing technical problem. Summary of the Invention

[0005] In view of this, the present invention provides a heat exchanger for a dilution refrigerator, which improves efficiency through the synergistic effect of a first pore system and a second pore system. 3 He solution and 3 He- 4 The permeability of the He mixture allows the packing material to achieve a larger heat exchange area by increasing its thickness, thereby improving its compatibility with dilution chillers.

[0006] To achieve the above objectives, the present invention provides a heat exchanger for a dilution refrigerator, comprising a plurality of sequentially connected heat exchange units, each heat exchange unit comprising: a heat-conducting element; and two covers respectively disposed on both sides of the heat-conducting element to define a first chamber and a second chamber, wherein the first chamber contains a flow-through component. 3 He solution, with flow in the aforementioned second chamber. 3 He solution and 4 A mixture of He solutions, to make the above 3 The He solution and the above-mentioned mixture exchange heat through the above-mentioned heat-conducting element; a filler is disposed in the above-mentioned first chamber and the above-mentioned second chamber, and a first pore system is formed inside the filler to facilitate the increase of the above-mentioned heat exchange. 3 The heat exchange area between the He solution and the above mixture, and the filling material further having a second pore system, are suitable for increasing the heat exchange area while simultaneously increasing the above... 3 The depth to which the He solution and the above mixture penetrate into the interior of the above filler.

[0007] According to an embodiment of the present invention, the first pore system includes a plurality of heat exchange pores, and the second pore system includes a plurality of seepage pores, wherein the diameter of the seepage pores is larger than the diameter of the heat exchange pores.

[0008] According to an embodiment of the present invention, the filler comprises a sintered body made of nano-silver powder.

[0009] According to an embodiment of the present invention, the first chambers of adjacent heat exchange units are connected, and the second chambers of adjacent heat exchange units are connected; wherein the connected first chambers serve as the hot side of the heat exchanger, and the connected second chambers serve as the cold side of the heat exchanger.

[0010] The present invention also provides a method for manufacturing a heat exchanger for a dilution refrigerator as described in any of the above embodiments, comprising: preparing a second porous framework using 3D printing technology; placing the second porous framework into a mold, filling the mold with nano-silver powder to cover the second porous framework and compacting it into a block; removing the second porous framework using a solvent, retaining the nano-silver powder block; sintering the nano-silver powder block to form a sintered body having a first porous system and a second porous system; repeating the above steps to prepare multiple sintered bodies, processing multiple heat-conducting components and multiple covers; placing the sintered bodies into a first chamber and a second chamber and sealing them to obtain multiple heat exchange units; and connecting the multiple heat exchange units through pipes.

[0011] Embodiments of the present invention also provide a dilution refrigerator, including a heat exchanger for a dilution refrigerator as described in any of the above embodiments, and further including: a mixing chamber, wherein the mixing chamber stores a material located in the upper layer. 3 He condensed phase and the lower layer 3 He dilution phase, the above 3 The concentrated phase of He is configured to respond to the above 3 He dilution phase 3 The concentration of He decreased, towards the above 3 He dilution phase compensation 3 He simultaneously absorbs ambient heat for cooling; the evaporator section, connected to the aforementioned mixing chamber, stores at least a portion of the aforementioned... 3 He dilution phase, the above-mentioned evaporation section is configured to dilute the above-mentioned phase. 3 He dilution phase 3 He evaporates and is then condensed to form... 3 He solution flows back to the above 3 The concentrated phase is used to form a circulating dilution refrigeration with the aforementioned mixing chamber; the aforementioned heat exchanger is disposed between the aforementioned mixing chamber and the aforementioned evaporation section, and has a hot side and a cold side, wherein the hot side is suitable for... 3 He solution flows back to the above 3 He concentrated phase, the above-mentioned cold side is suitable for connecting the above-mentioned mixing chamber and the above-mentioned evaporation section. 3 He is diluted phase to exchange heat with the aforementioned hot side.

[0012] According to an embodiment of the present invention, the evaporation section includes an evaporation chamber, which communicates with the mixing chamber via the cold side to store at least a portion of the mixture. 3 He dilution phase, suitable for the above 3 He dilution phase 3 He evaporates 3 He steam; 3 The internal circulation device is configured to adsorb the contents of the evaporation chamber in response to the device temperature being in the second temperature zone. 3He vapor, and in response to the device temperature being in the first temperature zone, release 3 He steam, the above 3 He vapor, after being released and condensed, enters the hot side of the heat exchanger.

[0013] According to embodiments of the present invention, the above 3 The internal circulation device includes: at least one pair of circulation bodies disposed between a primary cold plate and a secondary cold plate spaced apart in a vertical direction, wherein the temperature of the primary cold plate is in a first temperature zone and the temperature of the secondary cold plate is in a second temperature zone, and each circulation body in each pair of circulation bodies has the function of moving downward to contact the secondary cold plate and cooling down to the second temperature zone to adsorb the evaporation chamber. 3 The first state of He vapor, and its upward movement to contact the aforementioned primary cold plate and rise to the aforementioned first temperature zone, so as to be released into the aforementioned mixing chamber. 3 The second state of He vapor; a drive mechanism adapted to drive two of the two circulating bodies in each pair to move vertically to switch between the first state and the second state, and to keep the two circulating bodies in different states, thus constituting a configuration. 3 He steam internal circulation path.

[0014] According to an embodiment of the present invention, the above-mentioned circulation body includes: a movable tube extending in a vertical direction and connected to the drive mechanism, the movable tube having a shape suitable for accommodating... 3 The first containment cavity for He vapor; two heat-conducting valve seats, respectively located at two openings of the aforementioned movable tube, and at least partially extending into the aforementioned movable tube, wherein the heat-conducting valve seats are formed with a supply... 3 He is a steam flow channel; two elastic sleeves are adapted to connect the movable tube and the heat-conducting valve seat, the elastic sleeves, the heat-conducting valve seat and the movable tube define a second receiving cavity communicating with the flow channel, the movable tube is configured to compress one of the elastic sleeves under the drive of the drive mechanism, such that the second receiving cavity on the same side as the elastic sleeve communicates with the first receiving cavity.

[0015] According to an embodiment of the present invention, each of the above-mentioned circulating bodies further includes an adsorption element disposed within the first receiving cavity and configured to release under conditions of a first temperature zone. 3 He vapor, and adsorption in the second temperature zone 3 He steam.

[0016] The heat exchanger for a dilution refrigerator provided by this invention, through the combined action of a first pore system and a second pore system, enables... 3He solutions and mixtures can easily penetrate into the packing material and exchange heat effectively, allowing the packing material to achieve a larger heat exchange area by increasing its thickness. This results in better compatibility with dilution refrigerators and avoids excessive increases in the bottom area, which could lead to space constraints. 3 Waste of He solution and mixture. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of a heat exchanger for a dilution refrigerator provided in an embodiment of the present invention;

[0018] Figure 2 This is a three-dimensional structural diagram of the heat exchange unit of the heat exchanger provided in the embodiment of the present invention;

[0019] Figure 3 This is a cross-sectional structural diagram of the heat exchange unit provided in an embodiment of the present invention;

[0020] Figure 4 This is a cross-sectional view of the heat exchange unit provided in the embodiment of the present invention;

[0021] Figure 5 This is a flowchart of a method for manufacturing a heat exchanger for a dilution refrigerator provided in an embodiment of the present invention;

[0022] Figure 6 This is a three-dimensional structural diagram of the heat exchanger for a dilution refrigerator connected to the mixing chamber and the evaporation chamber, provided in an embodiment of the present invention.

[0023] Figure 7 This is a schematic plan view of the heat exchanger for a dilution refrigerator connected to the mixing chamber and the evaporation chamber, as provided in an embodiment of the present invention.

[0024] Figure 8 This is a schematic plan view of the dilution refrigeration machine provided in an embodiment of the present invention;

[0025] Figure 9 This is a three-dimensional structural diagram of a dilution refrigeration machine provided in another embodiment of the present invention;

[0026] Figure 10 This is provided by the embodiments of the present invention. 3 Schematic diagram of the internal circulation device;

[0027] Figure 11 This is provided by the embodiments of the present invention. 3 3D structural diagram of the internal circulation device;

[0028] Figure 12 This is provided by the embodiments of the present invention. 3 Three-dimensional structural diagram of the main circulation body of the He internal circulation device;

[0029] Figure 13This is the dilution refrigeration machine provided in the embodiments of the present invention. 3 A three-dimensional cross-sectional view of the main circulation body of the internal circulation device;

[0030] Figure 14 This is the dilution refrigeration machine provided in the embodiments of the present invention. 3 Partial cross-sectional view of the main body of the internal circulation device;

[0031] Figure 15 yes Figure 13 3D structural diagram after removing the elastic sleeve and valve body;

[0032] Figure 16 This is provided by another embodiment of the present invention. 3 He internal circulation device 3D structure diagram.

[0033] In the accompanying drawings, the meanings of the reference numerals are as follows:

[0034] 1. Heat exchange unit;

[0035] 11. Thermal conductive components;

[0036] 12. Cover body;

[0037] 13. Filler;

[0038] 2. Mixing chamber;

[0039] 3. Evaporation chamber;

[0040] 4. Circulation body;

[0041] 41. Movable tube body;

[0042] 411. First receiving cavity;

[0043] 412. Large diameter section;

[0044] 413. Small-diameter section;

[0045] 4131, Through hole;

[0046] 42. Thermally conductive valve seat;

[0047] 421. Heat transfer plate;

[0048] 422. Valve body;

[0049] 423. Flow channel;

[0050] 43. Flexible sleeve;

[0051] 431. Second receiving cavity;

[0052] 44. Adsorption components;

[0053] 441. Activated carbon;

[0054] 442. Support plate;

[0055] 5. Drive mechanism;

[0056] 6. First-class cold dish;

[0057] 7. Secondary cold plate;

[0058] 8. Level 3 cold dish;

[0059] 9. Precooling unit;

[0060] 90. Room temperature plate;

[0061] 91. Hot end;

[0062] 92. Level 1 cold block;

[0063] 93. Secondary cooling block. Detailed Implementation

[0064] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0065] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0066] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0067] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0068] Figure 1 This is a three-dimensional structural diagram of a heat exchanger for a dilution refrigerator provided in an embodiment of the present invention. Figure 2 This is a three-dimensional structural diagram of the heat exchange unit of the heat exchanger provided in the embodiment of the present invention. Figure 3 This is a cross-sectional structural diagram of the heat exchange unit provided in an embodiment of the present invention. Figure 4 This is a cross-sectional view of the heat exchange unit provided in an embodiment of the present invention.

[0069] Embodiments of the present invention provide a heat exchanger for a dilution refrigeration unit, such as... Figures 1 to 4 As shown, the device includes multiple heat exchange units 1 connected in sequence. Each heat exchange unit 1 includes a heat-conducting element 11, two covers 12, and a filler 13. The two covers 12 are respectively positioned on both sides of the heat-conducting element 11 to define a first chamber and a second chamber. The first chamber contains a flow-through component. 3 He solution, with flow in the second chamber. 3 He solution and 4 A mixture of He solutions, to make 3 The He solution and the mixture exchange heat through the heat-conducting element 11. A packing 13 is disposed in the first and second chambers, and a first pore system is formed inside the packing 13 to facilitate the increase of heat exchange. 3 The heat exchange area between the He solution and the mixture is increased. A second pore system is also formed inside the packing 13, which is suitable for increasing the heat exchange area while simultaneously increasing... 3 The depth to which the He solution and mixture penetrate into the interior of the filler 13.

[0070] In this embodiment, the heat-conducting element 11 and the two covers 12 enclose the first chamber and the second chamber, when 3 When the He solution and the mixture flow through the packing 13, they exchange heat with the packing 13. The packing 13 on both sides of the heat-conducting element 11 further exchanges heat through the heat-conducting element 11, so as to realize the use of the mixture to heat the contents of the packing 13. 3 He solution cooling. The packing material 13 has a porous structure with two pore systems. The first pore system primarily increases the heat exchange area, while the second pore system also contributes to increasing the heat exchange area, but its main function is to increase the heat exchange area. 3 The depth to which the He solution and mixture penetrate into the interior of the packing 13. Through the cooperation of the second and first pore systems, the packing 13 can increase its volume by increasing its thickness, thereby further increasing the heat exchange area without causing [unspecified issues]. 3 To address the issue of He solution and mixtures being difficult to penetrate, and to avoid simply increasing the bottom area leading to excessively large volumes of the filler 13 and heat exchange unit 1, thus occupying too much arrangement space and significantly increasing [the burden on the system]. 3 Dosage of He solution used.

[0071] In addition, the pore size of the first pore system can be further reduced and the pore density increased. Due to the auxiliary permeation effect of the second pore system, the problems of increased flow resistance and difficulty in permeation can be effectively alleviated.

[0072] In some embodiments, the first pore system includes a plurality of heat exchange pores, and the second pore system includes a plurality of seepage pores, wherein the diameter of the seepage pores is larger than the diameter of the heat exchange pores.

[0073] In this implementation, because the pore size is relatively large, the flow resistance to the fluid is small, making it suitable as a working medium ( 3 The He solution and mixture penetrate deeply into the main channels inside the packing 13. Due to the small pore size of the heat exchange pores, a large number of micro-channels with a large surface area can be formed per unit volume. By setting two pore systems with different pore sizes, the trade-off between heat exchange area and penetration depth is broken. The large-diameter permeation pores ensure permeability, making it possible to increase the thickness of the packing 13; while the small-diameter heat exchange pores efficiently provide the required heat exchange area throughout the entire volume activated by the permeation pores.

[0074] According to an embodiment of the present invention, the filler 13 comprises a sintered body made of nano-silver powder.

[0075] In this implementation, silver exhibits high thermal conductivity, significantly higher than other thermally conductive materials even in the temperature range of several Kelvin to tens of mKelvin. Furthermore, the sintering process creates numerous heat exchange pores between the silver particles, forming the first pore system. The sintered body made of nano-silver powder possesses both a porous heat exchange structure and high thermal conductivity, effectively improving... 3 Heat transfer efficiency between He solution and mixture and packing 13.

[0076] In some implementations, such as Figure 1 As shown, the first chambers of adjacent heat exchange units 1 are connected, and the second chambers of adjacent heat exchange units 1 are connected, wherein the connected first chambers serve as the hot side of the heat exchanger, and the connected second chambers serve as the cold side of the heat exchanger.

[0077] In this implementation, multiple heat exchange units 1 are connected in series, with higher temperatures... 3 The He solution flows in from one end of the hot-side channel and sequentially through the first chambers of each of the series-connected heat exchange units 1. Simultaneously, a lower-temperature mixture flows in from the other end of the cold-side channel, flowing in the opposite direction (towards...). 3 The He solution (flowing in the opposite direction) flows through the second chamber of each heat exchange unit 1 connected in series, and interacts with... 3The He solution exchanges heat in each heat exchange unit 1 through the heat-conducting element 11 and the packing 13. This allows a more uniform temperature gradient to be formed and maintained within the heat exchanger, resulting in a higher average heat exchange temperature difference and heat exchange efficiency.

[0078] Figure 5 This is a flowchart illustrating a method for manufacturing a heat exchanger for a dilution refrigerator, as provided in an embodiment of the present invention.

[0079] Embodiments of the present invention also provide a method for manufacturing a heat exchanger, used to manufacture the heat exchanger in any of the above embodiments, such as... Figure 5 As shown, the method includes steps S1-S7.

[0080] Step S1: Prepare the second pore system framework using 3D printing technology.

[0081] Step S2: Place the second porous framework into the mold, fill the mold with nano silver powder to cover the second porous framework, and compact it into a block.

[0082] Step S3: Use a solvent to remove the second porous framework, retaining the silver nanoparticles.

[0083] Step S4: Sinter the nano-silver powder block to form a sintered body with a first pore system and a second pore system.

[0084] Step S5: Repeat steps S1-S4 to prepare multiple sintered bodies, process multiple heat-conducting components 11 and multiple covers 12.

[0085] Step S6: Place the sintered body into the first chamber and the second chamber and seal them to obtain multiple heat exchange monomers 1.

[0086] Step S7: Connect multiple heat exchange units 1 through pipes.

[0087] In this implementation, a three-dimensional framework structure with a macroscopic morphology and spatial distribution of permeable pores is prepared using 3D printing technology with removable materials. The three-dimensional framework structure is then placed in a mold, the shape of which is approximately the same as the combined shape of the cover 12 and the heat-conducting component 11. Nano-silver powder is then filled and compacted to obtain a nano-silver powder block with a second porous framework inside. The second porous framework is then removed using a solvent, resulting in a nano-silver powder block with a second porous system. This is followed by firing to form a first porous system inside the nano-silver powder block. This effectively solves the problem of high processing difficulty in traditional pore-forming processes and reduces manufacturing costs.

[0088] In some alternative embodiments, the 3D printing molding technology includes, but is not limited to, thermal extrusion or photopolymerization, the material of the corresponding second porous framework is selected as plastic or resin, and the solvent removal can be selected as limonene.

[0089] In some alternative embodiments, the heat-conducting element 11 and the cover 12 are manufactured by casting or wire cutting methods, and the heat-conducting element 11 is preferably made of oxygen-free copper.

[0090] In some alternative embodiments, the heat-conducting element 11 and the cover 12 are connected by laser welding or indium sealing to ensure sealing performance in extremely low temperature environments.

[0091] In some alternative embodiments, the pipe connecting the heat exchange unit 1 is a stainless steel pipe.

[0092] Figure 6 This is a three-dimensional structural diagram of the heat exchanger for a dilution refrigerator, after connecting the mixing chamber and the evaporation chamber, according to an embodiment of the present invention. Figure 7 This is a plan view of the heat exchanger for a dilution refrigerator provided in an embodiment of the present invention, after connecting the mixing chamber and the evaporation chamber.

[0093] Embodiments of the present invention also provide a dilution refrigeration machine, such as Figure 6 and Figure 7 The diagram shows a mixing chamber 2, an evaporator section, and a heat exchanger for a dilution refrigerator as described in any of the above embodiments. The mixing chamber 2 stores materials located in the upper layer. 3 He condensed phase and the lower layer 3 He dilution phase, 3 The condensed phase of He was configured in response to 3 He dilution phase 3 The concentration of He decreased, towards 3 He dilution phase compensation 3 He simultaneously absorbs ambient heat for cooling. The evaporator section is connected to the mixing chamber 2 to store at least a portion of the heat. 3 He dilutes the phase, and the evaporation section is configured to... 3 He dilution phase 3 He evaporates and is then condensed to form... 3 He solution flow back 3 The concentrated phase is used to form a circulating dilution refrigeration system with mixing chamber 2. A heat exchanger is located between mixing chamber 2 and the evaporator section, and has a hot side and a cold side; the hot side is suitable for... 3 He solution flow back 3 He concentrated phase, cold side suitable for connecting mixing chamber 2 and evaporation section 3 He dilutes the phase to facilitate heat exchange with the hot side.

[0094] In this embodiment, the mixing chamber 2 stores 3 He condensed phase (i.e.) 3 He solution) and 3 He dilution phase (i.e.) 3 He solution and 4 (a mixture of He solution), in the evaporation section3 He is evaporated in response to a preset temperature to form 3 He steam, at this time in the evaporation section 3 The concentration of He decreased, and the mixture in chamber 2... 3 He condenses towards each other 3 He dilution phase compensation 3 He simultaneously absorbs heat to achieve dilution and refrigeration. 3 After being cooled and liquefied, the He vapor enters the hot side of the heat exchanger (i.e., the first chamber connected in sequence), where it interacts with the cold side (i.e., the second chamber connected in sequence). 3 He dilutes the phase through continuous heat exchange and eventually returns to mixing chamber 2. 3 He concentrated phase. By setting up a heat exchanger as in any of the above embodiments, not only is the heat exchange efficiency effectively increased, but it also avoids occupying too much horizontal space and reduces 3 He usage amount.

[0095] Figure 8 This is a plan view of the dilution refrigeration machine provided in an embodiment of the present invention.

[0096] According to embodiments of the present invention, such as Figure 8 As shown, the evaporation section includes an evaporation chamber 3 and 3 The internal circulation device, evaporation chamber 3 is connected to mixing chamber 2 via the cold side to store at least a portion of the contents. 3 He dilution phase, suitable for... 3 He dilution phase 3 He evaporates 3 He steam. 3 The internal circulation device is configured to, in response to the device temperature being in the second temperature zone, adsorb the contents of the evaporation chamber 3. 3 He vapor, and in response to the device temperature being in the first temperature zone, release 3 He steam, 3 He vapor enters the hot side of the heat exchanger after being condensed and released.

[0097] In this implementation, when the evaporation chamber 3 reaches the preset temperature, approximately 0.6-1K, typically 0.8K is selected. 3 The saturated vapor pressure of He is significantly higher than 4 He, therefore, is selectively evaporated. Inside evaporation chamber 3. 3 The He concentration subsequently decreased, and the concentration in mixing chamber 2... 3 The diluted phase is replenished through the cold side of the heat exchanger in evaporation chamber 3. 3 He. Evaporated 3 He steam is 3 He is drawn out by the internal circulation device and released into the mixing chamber 2 at a temperature not exceeding the first temperature zone, in order to reduce 3He carries heat with his steam.

[0098] In some alternative embodiments, the released 3 He steam first reacts with the vapor in evaporation chamber 3 3 He dilutes the phase heat transfer, this process 3 He steam exchanges heat through a pipe that runs through evaporation chamber 3, without interacting with... 3 He is in direct contact with the diluted phase. After initial heat exchange, 3 He steam enters the secondary heat exchange pipe, which is located between the heat exchanger and the evaporation chamber 3. The secondary heat exchange pipe is constructed as a double-layer pipe. 3 The diluted phase flows in the inner layer. 3 He vapor flows in the outer layer, where capillary structures can also be incorporated to assist in the flow. 3 He vapor liquefies and thus enters the hot side of the heat exchanger.

[0099] In some alternative embodiments, the secondary heat exchange conduit is configured as a spiral double-layer conduit extending in a vertical direction.

[0100] Figure 9 This is a three-dimensional structural diagram of a dilution refrigeration machine provided in another embodiment of the present invention.

[0101] In some other embodiments, such as Figure 9 As shown, in a dilution refrigeration unit, the heat exchanger can also employ other types of heat exchange structures, as long as they can achieve reflux. 3 He solution and the solution flowing out from mixing chamber 2 3 He can be obtained through heat exchange with the diluted phase.

[0102] Figure 10 This is provided by the embodiments of the present invention. 3 He internal circulation device plan view Figure 11 This is provided by the embodiments of the present invention. 3 He internal circulation device 3D structure diagram.

[0103] In some implementations, such as Figure 8 , Figure 10 and Figure 11 As shown, 3 The internal circulation device includes at least one pair of circulation bodies 4 and a drive mechanism 5. The at least one pair of circulation bodies 4 are disposed between a primary cold plate 6 and a secondary cold plate 7 that are spaced apart in a vertical direction. The temperature of the primary cold plate 6 is in a first temperature zone, and the temperature of the secondary cold plate 7 is in a second temperature zone. Each circulation body 4 in each pair has the function of moving downward to contact the secondary cold plate 7 and cooling down to the second temperature zone to adsorb the evaporation from the evaporation chamber 3. 3The first state of He vapor, and its upward movement to contact with the primary cold plate 6 and rise to the first temperature zone, so as to be released into the mixing chamber 2. 3 The second state of He vapor. The drive mechanism 5 is adapted to drive two of the two circulating bodies 4 in each pair of circulating bodies 4 to move vertically to switch between the first and second states, and to keep the two circulating bodies 4 in different states to form... 3 He steam internal circulation path.

[0104] In such an implementation, with 3 The internal circulation device includes a pair of circulation bodies 4 (i.e., two). For example, one circulation body 4 is in contact with the secondary cold plate 7, continuously adsorbing the generated... 3 He vapor, another circulating body 4 comes into contact with the primary cooling plate 6. After a period of time, the drive mechanism 5 is activated, causing one circulating body 4 to detach from the secondary cooling plate 7 and come into contact with the primary cooling plate 6, releasing it into the mixing chamber 2. 3 Meanwhile, He vapor is released, and at the same time, another circulating unit 4 detaches from the primary cold plate 6 and comes into contact with the secondary cold plate 7, adsorbing the generated vapor. 3 He steam. After a period of time, the drive mechanism 5 drives the two circulating bodies 4 to alternate again, and so on in a continuous cycle, effectively shortening the time. 3 The circulation path between the evaporation chamber 3 and the mixing chamber 2 prevents external heat from leaking into the low-temperature zone of the dilution refrigeration unit.

[0105] More specifically, the temperature range of the first temperature zone is approximately 30K-50K, and the temperature range of the second temperature zone is approximately 3K-4K. When the main body of the circulation system 4 is in the first temperature zone, it... 3 He vapor's adsorption capacity decreases, thus it is released outwards. 3 When He steam, the main body of the circulation system 4 is in the second temperature zone, for 3 The adsorption capacity of He vapor is significantly increased, thus enabling effective adsorption. 3 He steam. Released 3 After heat exchange, the steam cools and condenses to form... 3 The He solution eventually flows back to mixing chamber 2, while the solution in evaporation chamber 3... 3 He's concentration decreased due to evaporation, prompting the mixing chamber 2 to... 3 He replenishes the evaporation chamber 3, thus forming a complete circulation path. During this circulation process, 3 He vapor can only reach temperatures of 30K-50K under standard atmospheric pressure. 3 He has a condensation temperature of approximately 3.2 K, and only a small amount of heat needs to be released to complete the liquefaction and reflux.

[0106] Compared to traditional 3 He-cycle scheme, 3He vapor is drawn to room temperature (approximately 300 K) by a pump unit, and requires pressurization and multi-stage heat exchange for cooling to complete liquefaction. The present invention provides... 3 The internal circulation device effectively improves circulation efficiency and significantly reduces heat leakage.

[0107] Figure 12 This is provided by the embodiments of the present invention. 3 He internal circulation device circulation main body three-dimensional structure diagram Figure 13 This is the dilution refrigeration machine provided in the embodiments of the present invention. 3 Cross-sectional perspective view of the main circulation body of the He internal circulation device. Figure 14 This is the dilution refrigeration machine provided in the embodiments of the present invention. 3 Partial cross-sectional view of the main circulation body of the He internal circulation device. Figure 15 yes Figure 13 Three-dimensional structural diagram after removing the elastic sleeve and valve body.

[0108] According to embodiments of the present invention, such as Figure 10 , Figure 12 and Figure 13 As shown, the circulation body 4 includes a movable tube 41, two heat-conducting valve seats 42, and two elastic sleeves 43. The movable tube 41 extends vertically and is connected to the drive mechanism 5. The movable tube 41 has a design suitable for accommodating... 3 The first containment cavity 411 for He vapor. Two heat-conducting valve seats 42 are located at the two openings of the movable tube 41, and at least partially extend into the movable tube 41. The heat-conducting valve seats 42 have a supply... 3 He steam flow channel 423; two elastic sleeves 43 are adapted to connect movable tube body 41 and heat conduction valve seat 42, the elastic sleeves 43, heat conduction valve seat 42 and movable tube body 41 define a second receiving cavity 431 communicating with the flow channel 423, the movable tube body 41 is configured to compress one of the elastic sleeves 43 under the drive of the drive mechanism 5, so that the second receiving cavity 431 on the same side as the elastic sleeve 43 communicates with the first receiving cavity 411.

[0109] In such an implementation, such as Figure 12 As shown, the movable tube 41 is constructed as a hollow tube extending vertically, and two heat-conducting valve seats 42 are disposed at the openings at the upper and lower ends of the movable tube 41 (and...). Figure 12 (The upper and lower ends are consistent), and the two elastic sleeves 43 are used to connect each heat-conducting valve seat 42 to the movable tube body 41. In other words, the movable tube body 41 is suspended between the two heat-conducting valve seats 42 with the support of the two elastic sleeves 43, and has no direct contact with the heat-conducting valve seats 42.

[0110] When the movable tube 41 begins to move under the drive of the drive mechanism 5, the movable tube 41, the elastic sleeve 43, and the heat-conducting valve seat 42 initially move synchronously upwards and downwards, at which point the elastic sleeve 43 hardly deforms. When the heat-conducting valve seat 42 moves to abut against the primary cold plate 6 / secondary cold plate 7, the movable tube 41 begins to compress the elastic sleeve 43 to gradually approach the heat-conducting valve seat 42, and the second receiving cavity 431 subsequently connects with the first receiving cavity 411. As the movable tube 41 continues to move until it contacts the heat-conducting valve seat 42, the primary cold plate 6 / secondary cold plate 7 begins to exchange heat with the movable tube 41 through the heat-conducting valve seat 42. When the temperature of the movable tube 41 reaches the first temperature zone / second temperature zone... 3 He vapor is released from the first receiving chamber 411 and flows sequentially through the second receiving chamber 431 and the flow channel 423 to the mixing chamber 2, or it is drawn into the first receiving chamber 411 from the evaporation chamber 3 sequentially through the flow channel 423 and the second receiving chamber 431.

[0111] Further according to embodiments of the present invention, such as Figure 14 As shown, each circulation body 4 also includes an adsorption element 44 disposed within the first receiving cavity 411 and configured to release under conditions of a first temperature zone. 3 He vapor, and adsorption in the second temperature zone 3 He steam.

[0112] In this implementation, when the circulating body 4 comes into contact with the secondary cold plate 7 and cools down to the second temperature zone, the temperature of the adsorbent 44 subsequently drops to its high-efficiency adsorption temperature, thus affecting... 3 The adsorption capacity of He vapor increased significantly, and the adsorption capacity from evaporation chamber 3 was also increased. 3 He vapor. When the circulating body 4 comes into contact with the primary cold plate 6 and heats up to the first temperature zone, the temperature of the adsorbent 44 rises accordingly, affecting... 3 The adsorption capacity of helium vapor decreases sharply, and the previously adsorbed... 3 He vapor is released and flows into mixing chamber 2. This utilizes the adsorption capacity of adsorbent 44 to transport vapor as temperature changes. 3 He steam avoids the vibration effects present when using pump sets, while temperature changes are limited to between the first and second temperature zones, i.e., the low-temperature zone of the dilution chiller, thus avoiding the input of ambient heat.

[0113] In some alternative embodiments, such as Figure 13 and Figure 14As shown, each heat-conducting valve seat 42 includes a heat-conducting disk 421 and a valve body 422. A flow channel 423 is formed in the heat-conducting disk 421, and an elastic sleeve 43 is connected between the heat-conducting disk 421 and the movable tube 41. The valve body 422 extends from the heat-conducting disk 421 into the movable tube 41 and is configured to reciprocate axially relative to the movable tube 41 to close or open an opening on the same side as the valve body 422.

[0114] In this embodiment, the heat-conducting plate 421 serves as the heat transfer medium between the primary cold plate 6 / secondary cold plate 7 and the heat-conducting element 11. The valve body 422 extends into the movable tube 41. When the movable tube 41 and the heat-conducting plate 421 move closer together, the valve body 422 disengages from the inner wall of the movable tube 41, connecting the first receiving cavity 411 and the second receiving cavity 431. When the movable tube 41 and the heat-conducting plate 421 move away from each other until the valve body 422 re-contacts the inner wall of the movable tube 41, the connection between the first receiving cavity 411 and the second receiving cavity 431 is severed.

[0115] According to embodiments of the present invention, such as Figure 15 As shown, the movable tube 41 has a large-diameter section 412 and small-diameter sections 413 located at both ends of the large-diameter section 412. The diameter of the large-diameter section 412 is approximately the same as the diameter of the heat-conducting plate 421 and the diameter of the elastic sleeve 43, and is used to compress the elastic sleeve 43. The small-diameter section 413 extends into the elastic sleeve 43 and is used to contact the heat-conducting plate 421. The valve body 422 extends into the small-diameter section 413. Multiple through holes 4131 are provided on the side wall of the small-diameter section 413. The axis of the through holes 4131 is perpendicular to the vertical direction to allow the small-diameter section 413 to contact the heat-conducting plate 421. 3 He vapor flows from the first receiving cavity 411 to the second receiving cavity 431.

[0116] In some alternative embodiments, such as Figure 15 As shown, the adsorbent 44 includes activated carbon 441 and a support plate 442. The activated carbon 441 is suitable for adsorption or release. 3 He steam, the support plate 442 is installed on the inner wall of the movable tube 41, and is suitable for holding activated carbon 441.

[0117] In this embodiment, activated carbon 441 has a high specific surface area and microporous structure, and is able to respond to temperature changes from the first temperature zone to the second temperature zone. 3 He vapor is adsorbed and released. Holding it in the support plate 442 can prevent the particles of activated carbon 441 from leaking into the second receiving chamber 431 and the outside of the circulation body 4, or from blocking the flow channel 423.

[0118] In some optional embodiments, two support disks 442 are provided, with activated carbon 441 sandwiched between the two support disks 442. The support disks 442 are threadedly connected to the inner wall of the movable tube 41.

[0119] In some alternative embodiments, the heat transfer plate 421, the movable tube 41, and the support plate 442 are made of oxygen-free copper to efficiently and quickly transfer heat between the activated carbon 441 and the primary cold plate 6 / secondary cold plate 7, shortening the vacuum period that occurs during device operation due to the heating / cooling process.

[0120] In some alternative embodiments, the support plate 442 is configured as a porous structure with pore sizes smaller than the particle size of the activated carbon 441, so as to allow for the holding of the activated carbon 441 while allowing for the holding of the activated carbon 441. 3 He steam passed through.

[0121] In this implementation, because the pore size of the support plate 442 is smaller than the particle size of the activated carbon 441, it forms an effective physical sieve, reliably confining all the activated carbon 441 particles and preventing them from moving or leaking under any circumstances (such as vibration, airflow impact, etc.), thereby ensuring operational stability. Furthermore, the support plate 442 also allows... 3 He vapor passes through and comes into full contact with activated carbon 441 without the need for specially designed channels, and the low flow resistance is beneficial for improving adsorption / release efficiency.

[0122] In some alternative embodiments, the support plate 442 is made of foamed stainless steel, which meets the usage requirements while providing high structural rigidity and strength.

[0123] In some optional embodiments, a stainless steel sleeve is fitted over the active tube 41 to ensure that the temperature of the adsorption element 44 changes only under the influence of the primary cold plate 6 and the secondary cold plate 7, thereby reducing interference.

[0124] In some other embodiments, such as Figure 16 As shown, 3 The internal circulation device includes two pairs of circulation bodies 4, and the two pairs of circulation bodies 4 are activated at a preset time interval.

[0125] In this implementation, when the circulation body 4 switches states under the drive of the drive mechanism 5, the temperature of the adsorption element 44 in the moving tube 41 needs a certain period of time to reach the first temperature zone / second temperature zone. During this process, the adsorption element 44 will neither adsorb nor absorb... 3 He will not release steam. 3He vapor causes a brief shutdown (or standby) time after the switching state. This is addressed by adding another pair of circulating units 4, which are started at a preset time interval from the previous pair. When the previous pair of circulating units 4 switches state and enters the shutdown (or standby) time, the additional pair of circulating units 4 continues adsorption and release operations, preventing the entire dilution refrigeration unit from... 3 The He loop is interrupted.

[0126] According to an embodiment of the present invention, the two loop bodies 4 in each pair of loop bodies 4 switch states every cycle duration, and the preset time interval is half a cycle duration.

[0127] In this implementation, by setting the preset time interval to half a working cycle duration, not only can the two pairs of cyclic main bodies 4 cover each other's downtime (or standby time), but the stability of long-term operation can also be improved. If the preset time interval is set to 1 / 3 or 1 / 4 of a cycle duration, although it can operate normally in a short time, after multiple cycles, the downtime (or standby time) of the two pairs of cyclic main bodies 4 will still overlap.

[0128] In some alternative embodiments, the drive mechanism 5 includes multiple cylinders and a controller, each cylinder driving a circulating body 4, and the controller controlling the corresponding cylinder action and the timing of the action.

[0129] In some alternative embodiments, such as Figure 9 As shown, the above-mentioned dilution refrigeration unit also includes a multi-stage cold plate and a pre-cooling unit 9. The multi-stage cold plate includes a first-stage cold plate 6, a second-stage cold plate 7, and a third-stage cold plate 8 arranged vertically at intervals. The circulation body 4 is disposed between the first-stage cold plate 6 and the second-stage cold plate 7, and the mixing chamber 2 is disposed on the third-stage cold plate 8. The pre-cooling unit 9 is suitable for cooling the first-stage cold plate 6 and the second-stage cold plate 7 to the first temperature zone and the second temperature zone, respectively.

[0130] In this embodiment, the precooling unit 9 includes a hot end 91, a primary cold head 92, and a secondary cold head 93. The hot end 91 is disposed on the room temperature plate 90 (temperature approximately 300K), and the primary cold head 92 is disposed between the room temperature plate 90 and the primary cold plate 6. The secondary cold head 93 is disposed between the primary cold plate 6 and the secondary cold plate 7. The cooling power of the primary cold head 92 is higher than that of the secondary cold head 93, so as to cool the primary cold plate 6 and the secondary cold plate 7 to the first temperature zone and the second temperature zone, respectively. At least one tertiary cold plate 8 is provided in the mixing chamber 2, and one can also be provided in the evaporation chamber 3 and the heat exchanger.

[0131] Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0132] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A heat exchanger for a dilution refrigeration machine, characterized in that, It includes multiple heat exchange units connected in sequence, wherein the heat exchange unit includes: Thermal conductive components; Two enclosures are respectively placed on both sides of the heat-conducting component to define a first chamber and a second chamber, wherein the first chamber contains flowing... 3 He solution, with flow in the second chamber. 3 He solution and 4 A mixture of He solutions, to make the 3 The He solution and the mixture exchange heat through the heat-conducting element; A filler body is disposed in the first chamber and the second chamber, and a first pore system is formed inside the filler body to facilitate increasing the filling depth. 3 The heat exchange area between the He solution and the mixture is further enhanced by a second pore system formed inside the filler, which is suitable for increasing the heat exchange area while simultaneously increasing the heat exchange surface area. 3 The depth to which the He solution and the mixture penetrate into the interior of the filler.

2. The heat exchanger for a dilution refrigerator according to claim 1, characterized in that, The first pore system includes multiple heat exchange pores, and the second pore system includes multiple seepage pores, wherein the diameter of the seepage pores is larger than the diameter of the heat exchange pores.

3. The heat exchanger for a dilution refrigerator according to claim 2, characterized in that, The filler comprises a sintered body made of nano-silver powder.

4. The heat exchanger for a dilution refrigerator according to claim 2, characterized in that, The first chambers of adjacent heat exchange units are connected, and the second chambers of adjacent heat exchange units are connected. The first chamber, which is connected to the heat exchanger, serves as the hot side of the heat exchanger, and the second chamber, which is connected to the heat exchanger, serves as the cold side of the heat exchanger.

5. A method for manufacturing a heat exchanger, characterized in that, For manufacturing a heat exchanger for a dilution refrigeration unit according to any one of claims 1-4, comprising: The second porous framework was prepared using 3D printing technology. The second porous framework is placed into a mold, and nano-silver powder is filled into the mold to cover the second porous framework and then compacted into a block. The second porous framework was removed using a solvent, while the silver nanoparticles were retained. The nano-silver powder block is sintered to form a sintered body with a first pore system and a second pore system; Repeat the above steps to prepare multiple sintered bodies, and process multiple heat-conducting components and multiple covers; The sintered body is placed into the first chamber and the second chamber and sealed to obtain multiple heat exchange units; Multiple heat exchange units are connected by pipes.

6. A dilution refrigeration machine, characterized in that, Including the heat exchanger for a dilution refrigerator as described in any one of claims 1-4, further comprising: The mixing chamber stores the contents located in the upper layer. 3 He condensed phase and the lower layer 3 He dilution phase, the 3 The concentrated phase of He is configured to respond to the aforementioned 3 He dilution phase 3 The concentration of He decreased, towards the 3 He dilution phase compensation 3 He simultaneously absorbs heat from the surrounding environment to cool down; The evaporation section is connected to the mixing chamber to store at least a portion of the mixture. 3 He dilution phase, the evaporation section is configured to dilute the phase. 3 He dilution phase 3 He evaporates and is then condensed to form... 3 He solution flows back to the 3 He concentrated phase, to form a circulating dilution refrigeration with the mixing chamber; The heat exchanger is disposed between the mixing chamber and the evaporation section, and has a hot side and a cold side, the hot side being suitable for... 3 He solution flows back to the 3 He concentrated phase, the cold side is suitable for connecting the mixing chamber and the evaporation section. 3 He is diluted phase to exchange heat with the hot side.

7. The dilution refrigeration machine according to claim 6, characterized in that, The evaporation section includes: The evaporation chamber, connected to the mixing chamber via the cold side, is used to store at least a portion of the contents. 3 He dilution phase, suitable for diluting the above 3 He dilution phase 3 He evaporates 3 He steam; 3 The internal circulation device is configured to adsorb substances from the evaporation chamber in response to the device temperature being in the second temperature zone. 3 He vapor, and in response to the device temperature being in the first temperature zone, release 3 He steam, the 3 He vapor enters the hot side of the heat exchanger after being condensed and released from heat.

8. The dilution refrigeration machine according to claim 7, characterized in that, The 3 The internal circulation device includes: At least one pair of circulating bodies are disposed between a primary cold plate and a secondary cold plate spaced apart in a vertical direction. The temperature of the primary cold plate is in a first temperature zone, and the temperature of the secondary cold plate is in a second temperature zone. Each circulating body in each pair has the function of moving downward to contact the secondary cold plate and cooling down to the second temperature zone to adsorb substances from the evaporation chamber. 3 The first state of He vapor, and its upward movement to contact the primary cold plate and rise to the first temperature zone for release into the mixing chamber. 3 The second state of He vapor; A drive mechanism is adapted to drive two of the loop bodies in each pair of loop bodies to move vertically to switch between the first state and the second state, and to keep the two loop bodies in different states, thereby constituting a configuration. 3 He steam internal circulation path.

9. The dilution refrigeration machine according to claim 8, characterized in that, The loop body includes: A movable tube, extending vertically and connected to the drive mechanism, is provided with a design suitable for accommodating... 3 The first cavity containing He vapor; Two heat-conducting valve seats are respectively located at two openings of the movable tube body, and at least partially extend into the movable tube body. The heat-conducting valve seats have a heat supply... 3 He's steam flow channel; Two resilient sleeves are adapted to connect the movable tube and the heat-conducting valve seat. The resilient sleeves, the heat-conducting valve seat, and the movable tube define a second receiving cavity communicating with the flow channel. The movable tube is configured to compress one of the resilient sleeves under the drive of the drive mechanism, such that the second receiving cavity on the same side as the resilient sleeve communicates with the first receiving cavity.

10. The dilution refrigeration machine according to claim 9, characterized in that, Each of the circulating bodies further includes an adsorption element disposed within the first receiving cavity and configured to release under conditions of a first temperature zone. 3 He vapor, and adsorption in the second temperature zone 3 He steam.

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