WORKING MEDIUM PURIFICATION DEVICE AND REFRIGERATION SYSTEM

Abstract

 A working fluid purification device and a refrigeration system are provided. The working fluid purification device for purifying a working fluid of a refrigeration apparatus (9) includes: a cold trap mechanism (1), including: a cold trap body (12) mounted on a cold head (3) of a first refrigerator and in thermal communication with the cold head (3), so as to be cooled by the cold head (3) to a first temperature for adsorbing impurities; a vacuum enclosure (11) covering the cold trap body (12) defines a vacuum cavity which is evacuated to a vacuum state, so as to thermally isolate the cold trap body (12) from external environment; a piping mechanism (5), including: a first branch (51) connected in parallel with a circulation pipeline (4) of the refrigeration apparatus (9) to be purified, and alternatively opened with the circulation pipeline (4); and a desorption mechanism configured to heat, in response to cut-off state of the first branch (51), the cold trap body (12) to a second temperature for desorbing impurities and extract impurities from the cold trap body (12).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of refrigeration apparatus technology, and in particular, to a working fluid purification device and a refrigeration system.

BACKGROUND

[0002] A refrigerator mainly transfers heat through a working fluid in a refrigeration cycle to achieve cooling. During the use of a refrigerator (such as a compression refrigerator, an absorption refrigerator, a Stirling refrigerator, a pulse tube refrigerator, a magnetic refrigerator, and a cryogenic refrigerator, etc.), a cold trap is often configured to remove a portion of impurities (such as oil vapor, water vapor, and impurity gases) in a sealed circulation system.

[0003] Taking impurity removal for a dilution refrigerator (a type of cryogenic refrigerator) as an example, a cold trap disposed in a sealed circulation system using helium-3 as a working fluid needs to use liquid nitrogen as a cooling medium, so that the cold trap is maintained at a low temperature (77K) in an adsorption state. To maintain the above low-temperature condition, the cold trap and liquid nitrogen need to be stored in a Dewar, which not only requires frequent replenishment of liquid nitrogen, but also occupies a large volume. Moreover, in actual operation, the cold trap needs to be cleaned regularly to maintain its adsorption performance.

[0004] When cleaning the cold trap, to desorb impurities adsorbed by the cold trap, the cold trap needs to be moved out of the liquid nitrogen environment and heated to room temperature. Therefore, online cleaning cannot be performed in the Dewar. In addition, in the process of removing the cold trap from the Dewar, liquid nitrogen loss will occur and there is a certain risk.

[0005] Therefore, how to provide a working fluid purification device and a refrigeration system that occupy a small space and allow online cleaning has become an urgent technical problem to be solved.

SUMMARY

[0006] To solve at least one of the above and other technical problems in the related art, the present disclosure provides a working fluid purification device and a refrigeration system.

[0007] The embodiments of the present disclosure provide a working fluid purification device configured to purify a working fluid of a refrigeration apparatus, including: a cold trap mechanism, comprising a cold trap body mounted on a cold head of a first refrigerator, wherein the cold trap body is in thermal communication with the cold head, so as to be cooled by the cold head to a first temperature for adsorbing impurities; a vacuum enclosure covering an outer side of the cold trap body, wherein the vacuum enclosure defines a vacuum cavity, and the vacuum cavity is configured to be evacuated to a vacuum state, so as to thermally isolate the cold trap body from an external environment; a piping mechanism, comprising a first branch configured to connect the cold trap body in parallel with a circulation pipeline of a refrigeration apparatus to be purified, wherein the first branch and the circulation pipeline are alternatively opened; and a desorption mechanism, configured to heat, in response to a cut-off state of the first branch, the cold trap body to a second temperature for desorbing the impurities, and extract the impurities from the cold trap body.

[0008] According to the embodiments of the present disclosure, the desorption mechanism comprises: a heating assembly configured to heat the cold trap body to the second temperature; and a first vacuum pump in communication with the cold trap body, wherein the first vacuum pump is configured to extract the impurities desorbed from the cold trap body.

[0009] According to the embodiments of the present disclosure, the heating assembly is disposed in the cold head; and the desorption mechanism further comprises a temperature acquisition assembly communicatively connected to the heating assembly, wherein the temperature acquisition assembly is configured to acquire a temperature of the cold head and/or the cold trap body.

[0010] According to the embodiments of the present disclosure, the piping mechanism further comprises a second branch disposed between the cold trap body and the circulation pipeline, and the second branch communicates the cold trap body with the circulation pipeline in response to the cut-off state of the first branch, so as to allow the working fluid remaining in the cold trap body to flow back to the circulation pipeline.

[0011] According to the embodiments of the present disclosure, the cold trap mechanism further comprises an inlet pipe and an outlet pipe, the inlet pipe is configured as an inlet end of the cold trap body, and the outlet pipe is configured as an outlet end of the cold trap body; and the inlet pipe and the outlet pipe are arranged side by side and in thermal communication with each other.

[0012] According to the embodiments of the present disclosure, the cold trap body comprises a first portion close to the cold head and a second portion away from the cold head; and a material of the first portion is different from a material of the second portion, and a thermal conductivity of the first portion is higher than a thermal conductivity of the second portion.

[0013] According to the embodiments of the present disclosure, the cold trap body is provided with an adsorption material, and the adsorption material is at least filled in the first portion.

[0014] The embodiments of the present disclosure further provide a refrigeration system, comprising: at least one refrigeration apparatus to be purified; at least one working fluid purification device, wherein the first branch of the working fluid purification device is connected in parallel with a circulation pipeline of each of the at least one refrigeration apparatus to be purified, and the first branch and the circulation pipeline are alternatively opened; and a second vacuum pump in communication with the vacuum enclosure of the working fluid purification device, wherein the second vacuum pump is configured to evacuate the vacuum cavity of the vacuum enclosure to the vacuum state. The working fluid purification device is configured to adsorb impurities in the working fluid in response to an open state of the first branch, and to desorb the impurities from the cold trap body of the working fluid purification device in response to the cut-off state of the first branch.

[0015] According to the embodiments of the present disclosure, the refrigeration system comprises a plurality of refrigeration apparatuses connected in parallel with each other.

[0016] According to the embodiments of the present disclosure, the refrigeration system comprises at least two working fluid purification devices, wherein the at least two working fluid purification devices are redundant to each other and are alternatively in communication with the refrigeration apparatus.

[0017] According to the working fluid purification device and the refrigeration system provided by the present disclosure, the cold trap body is mounted on the cold head of the first refrigerator, and the cold head replaces the liquid nitrogen used as a cold source in the related art. This not only reduces the volume of the device, but also prevents liquid nitrogen leakage and avoids the need to refill liquid nitrogen. The first branch of the piping mechanism connects the cold trap body in parallel with the circulation pipeline of the refrigeration apparatus, which allows the working fluid to switch between the circulation pipeline and the cold trap body. When the first branch is in the cut-off state, the working fluid flows through the circulation pipeline, and the cold trap body is isolated from the working fluid, so that the impurities adsorbed by the cold trap body can be cleaned online by the desorption mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 

FIG. 1 is a perspective view of a working fluid purification device according to an illustrative embodiment of the present disclosure;

FIG. 2 is a perspective view of the working fluid purification device shown in FIG. 1, showing a cold trap body;

FIG. 3 is a gas flow diagram of the working fluid purification device shown in FIG. 1;

FIG. 4 is a gas flow diagram of another illustrative embodiment of the working fluid purification device shown in FIG. 1;

FIG. 5 is a partial enlarged view of the working fluid purification device shown in FIG. 1, showing an adapter ring;

FIG. 6 is a block diagram of a refrigeration system according to an illustrative embodiment of the present disclosure; and

FIG. 7 is a block diagram of a refrigeration system according to another illustrative embodiment of the present disclosure, showing an embodiment with two working fluid purification devices.

[0019] In the drawings, the reference numerals have the following specific meanings:

1: cold trap mechanism;

11: vacuum enclosure;

12: cold trap body;

121: first portion;

122: second portion;

13: inlet pipe;

14: outlet pipe;

2: connection mechanism;

21: first flange;

22: sleeve;

23: second flange;

24: adapter ring;

3: cold head;

4: circulation pipeline;

5: piping mechanism;

51: first branch;

52: second branch;

53: third branch;

6: first vacuum pump;

7: evacuation pipeline;

8: second vacuum pump;

9: refrigeration apparatus;

91: first refrigeration apparatus;

92: second refrigeration apparatus;

93: third refrigeration apparatus; and

94: fourth refrigeration apparatus.

DETAILED DESCRIPTION OF EMBODIMENTS

[0020] To make the objectives, technical solutions, and advantages of the present disclosure clearer, the present disclosure is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0021] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the present disclosure. The terms "comprising," "including," and the like 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.

[0022] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that terms used herein should be interpreted as having meanings consistent with the context of the present specification, and should not be interpreted in an idealized or overly rigid manner.

[0023] When expressions similar to "at least one of A, B, and C, etc." are used, they should generally be interpreted in the sense commonly understood by those skilled in the art. For example, "a system having at least one of A, B, and C" includes, but is not limited to, systems that have A alone, B alone, C alone, A and B, A and C, B and C, and/or A, B, and C, etc. When expressions similar to "at least one of A, B, or C, etc." are used, they should generally be interpreted in the sense commonly understood by those skilled in the art. For example, "a system having at least one of A, B, or C" includes, but is not limited to, systems that have A alone, B alone, C alone, A and B, A and C, B and C, and/or A, B, and C, etc.

[0024] Taking a dilution refrigerator as an example, a dilution refrigerator is a millikelvin-level refrigeration apparatus that performs a dilution refrigeration cycle using a mixture of helium-3 and helium-4. At a temperature condition of 0.86K (the theoretical upper limit), helium-3 and helium-4 separate into two phases, where the concentrated phase mainly includes helium-3, and the diluted phase mainly includes a mixture of helium-3 and helium-4. In the dilution refrigeration process, a pump assembly is used to extract helium-3 from the diluted phase to an external environment for circulating heat exchange and then return it to the concentrated phase.

[0025] In circulation, the working fluid of the dilution refrigerator may carry various impurities, such as water vapor, oil vapor, and gas molecules (e.g., hydrogen, nitrogen, oxygen, etc.) that are not easily condensed at room temperature. These impurities circulate with the working fluid in a sealed circulation system (e.g., a circulation pipeline) and do not participate in the main heat absorption process (i.e., helium-3 entering the diluted phase), and consequently, they affect the performance and cooling capacity of the dilution refrigerator, thereby preventing the dilution refrigerator from reaching the required ultra-low temperature (e.g., millikelvin level), or even causing gas path blockage due to condensation or solidification of impurities, rendering the dilution refrigerator inoperable.

[0026] Currently, the cold trap mechanism used is mainly disposed in a Dewar. When cleaning the cold trap body sealed in liquid nitrogen, it is necessary to unseal the Dewar (at which point the liquid nitrogen in the Dewar vaporizes and leaks out until emptied; therefore, this process cannot be performed in a sealed indoor environment and results in significant consumption of liquid nitrogen), and remove the cold trap body from the Dewar to the external environment. After the cold trap body is heated to room temperature, desorption cleaning is performed. After cleaning, the cold trap body is reinstalled in the Dewar, and liquid nitrogen is replenished accordingly to re-cool the cold trap body until a suitable adsorption temperature is reached. Thus, the above process is complex to operate, time-consuming (up to several hours), and, because the cold trap body needs to be disassembled, online desorption cleaning of the cold trap body cannot be achieved.

[0027] On this basis, how to provide a working fluid purification device and a refrigeration system that occupy a small space and allow online cleaning has become a technical problem to be solved.

[0028] FIG. 1 is a perspective view of a working fluid purification device according to an illustrative embodiment of the present disclosure. FIG. 2 is a perspective view of the working fluid purification device shown in FIG. 1, showing a cold trap body. FIG. 3 is a gas flow diagram of the working fluid purification device shown in FIG. 1.

[0029] The working fluid purification device for purifying a refrigeration apparatus provided according to the present disclosure includes a cold trap mechanism 1, a piping mechanism 5, and a desorption mechanism. The cold trap mechanism 1 includes a cold trap body 12 and a vacuum enclosure 11. The cold trap body 12 is mounted on a cold head 3 of a first refrigerator and in thermal communication with the cold head 3, so as to be cooled by the cold head 3 to a first temperature for adsorbing impurities. The vacuum enclosure 11 covers an outer side of the cold trap body 12. The vacuum enclosure 11 defines a vacuum cavity, and the vacuum cavity is evacuated to a vacuum state, so as to thermally isolate the cold trap body 12 from an external environment. The piping mechanism 5 includes a first branch 51, the first branch 5 is used to connect the cold trap body 12 in parallel with a circulation pipeline 4 of a refrigeration apparatus 9 to be purified, and the first branch 51 and the circulation pipeline 4 are alternatively opened. The desorption mechanism is used to, in response to a cut-off state of the first branch 51, heat the cold trap body 12 to a second temperature for desorbing the impurities and extract the impurities from the cold trap body 12.

[0030] In an illustrative embodiment, as shown in FIGS. 1 to 3, the working fluid purification device further includes a second vacuum pump 8. For example, the second vacuum pump 8 is connected to a fitting (including, but not limited to, a standard threaded fitting, such as a model KN25 fitting) provided on the vacuum enclosure 11 via an evacuation pipeline 7. Further, a sixth valve (i.e., V6 as shown in FIG. 3) is provided on the evacuation pipeline 7. Thus, when the cold trap is in a first mode of operation (the working fluid flow direction indicated by the solid arrow in FIG. 3), the vacuum cavity defined in the vacuum enclosure is evacuated to a vacuum state by the second vacuum pump 8, so as to thermally isolate the cold trap body 12 from the external environment.

[0031] FIG. 4 is a gas flow diagram of another illustrative embodiment of the working fluid purification device shown in FIG. 1.

[0032] Referring to FIG. 4, another illustrative embodiment is shown. In this embodiment, the working fluid purification device is provided with only one vacuum pump (i.e., a first vacuum pump 6). For example, the evacuation pipeline 7 is connected to an inlet end of the first vacuum pump 6.

[0033] In such an implementation, because the timing for evacuating the vacuum enclosure 11 and the timing for evacuating the cold trap body 12 for desorption are staggered (the timing for evacuating the vacuum enclosure 11 is usually before the operation of the working fluid purification device, earlier than the timing for desorption cleaning of the cold trap body 12), the vacuum requirement may be met simply by the arrangement of the gas flow, thereby saving one vacuum pump and further reducing the volume of the working fluid purification device.

[0034] In an illustrative embodiment, as shown in FIGS. 1 and 2, the cold trap body 12 includes, but is not limited to, a roughly cylindrical tubular structure. Specifically, the cold trap body 12 defines an adsorption cavity, and the adsorption cavity is filled with an adsorption material. The adsorption material has a porous structure and a high specific surface area. For example, activated carbon, molecular sieves, copper mesh, activated alumina, silica gel, metal adsorbents, and at least one other material for adsorbing impurities (such as water vapor, oil vapor, and gas molecules that are not easily condensed at room temperature) passing through the cold trap body 12 may be used.

[0035] In an illustrative embodiment, as shown in FIGS. 1 and 2, the first refrigerator includes, but is not limited to, a 70K (Kelvin) low-power pulse tube cryogenic refrigerator. Specifically, the cold trap body 12 is directly mounted on the cold head 3 of the first refrigerator. The cold head 3 serves as a cold source and lowers the cold trap body 12 to the first temperature through thermal conduction. The first temperature includes, but is not limited to, 77K (Kelvin) or below. It should be understood that the embodiments of the present disclosure are not limited thereto.

[0036] For example, the first refrigerator may also be a GM refrigerator (i.e., a Gifford-McMahon refrigerator based on the Joule-Thomson effect) or another refrigerator and/or mechanical cold head configured to lower the cold trap body 12 to the first temperature or below.

[0037] In an illustrative embodiment, as shown in FIG. 3, the cold trap body 12 is connected in series on the first branch 51. Further, the first branch 51 also connects the cold trap body 12 in parallel with the circulation pipeline 4 of the refrigeration apparatus to be purified.

[0038] In an illustrative embodiment, as shown in FIG. 3, a first valve (i.e., V1 as shown in FIG. 3) is provided on the circulation pipeline 4. Further, a second valve (i.e., V2 as shown in FIG. 3) and a third valve (i.e., V3 as shown in FIG. 3) are respectively provided on the first branch 51 at positions located at an inlet end and an outlet end of the cold trap body 12.

[0039] The first valve (V1), the second valve (V2), and the third valve (V3) are cooperatively controlled. For example, when the first valve (V1) is in an open state, the second valve (V2) and the third valve (V3) are in a cut-off state; correspondingly, when the first valve (V1) is in a cut-off state, the second valve (V2) and the third valve (V3) are in an open state. In this way, the working fluid purification device switches between a first mode (the direction of the solid arrow shown in FIG. 3) in which impurities in the working fluid (e.g., helium-3) are adsorbed and a second mode (the direction of the dashed arrows shown in FIG. 3) in which the working fluid passes through without being adsorbed by the cold trap body 12.

[0040] When the working fluid purification device is in the second mode (the direction of the dashed arrows in FIG. 3), the desorption mechanism operates to clean impurities from the cold trap body 12 online while the refrigeration apparatus is continuously running (i.e., to desorb impurities from the adsorption material), so as to return the cold trap body 12 to the second temperature (e.g., room temperature) for desorption.

[0041] In such an implementation, the cold trap body 12 is mounted on the cold head 3 of the first refrigerator, replacing the liquid nitrogen in the related art as the cold source with the cold head 3. This not only reduces the volume of the device but also prevents leakage of liquid nitrogen, thereby improving safety of the device and avoiding consumption of liquid nitrogen. The first branch 51 of the piping mechanism 5 connects the cold trap body 12 in parallel with the circulation pipeline 4 of the refrigeration apparatus, allowing the working fluid (e.g., helium-3) to be switched between the circulation pipeline 4 and the cold trap body 12. When the first branch 51 is in a cut-off state, the working fluid passes through the circulation pipeline 4, and the cold trap body 12 is isolated from the working fluid, thereby enabling online cleaning of impurities adsorbed by the cold trap body 12 through the desorption mechanism.

[0042] Further, using the cold head 3 as the cold source, the cold trap body 12 may be switched between the first temperature and the second temperature when cleaning the cold trap body 12 without disassembling the working fluid purification device, thereby shortening the time length required for cleaning the cold trap body 12 and improving the convenience of cleaning the cold trap body 12. In this process, although in the second mode the working fluid (e.g., helium-3) directly enters the refrigeration apparatus (e.g., a dilution refrigerator) without being purified by adsorption through the cold trap body 12, the time length (e.g., about one hour) for desorption cleaning of the cold trap body 12 is negligible compared to the operating time length (measured in months, e.g., continuous operation for one month or more) of the refrigeration apparatus (e.g., a dilution refrigerator), and does not affect the performance or cooling capacity of the refrigeration apparatus (e.g., a dilution refrigerator). Thus, online cleaning of the cold trap body 12 is achieved. It should be understood that the refrigeration apparatus to be purified in the present disclosure includes, but is not limited to, a dilution refrigerator.

[0043] For example, the refrigeration apparatus to be purified may be any one of a compression refrigerator, an absorption refrigerator, a Stirling refrigerator, a pulse tube refrigerator, a magnetic refrigerator, and other cryogenic refrigerators. The above and following embodiments are merely illustrative descriptions of the working fluid purification device using a dilution refrigerator as an example, and the working fluid purification device may also be applied to any other refrigerator in which a cold trap mechanism is used to remove impurities from a working fluid.

[0044] According to an embodiment of the present disclosure, as shown in FIG. 2, the cold trap mechanism 1 further includes an inlet pipe 13 and an outlet pipe 14. The inlet pipe 13 serves as an inlet end of the cold trap body 12, and the outlet pipe 14 serves as an outlet end of the cold trap body 12. The inlet pipe 13 and the outlet pipe 14 are arranged side by side and in thermal communication with each other.

[0045] In an illustrative embodiment, as shown in FIG. 2, the inlet pipe 13 and the outlet pipe 14 of the cold trap mechanism 1 include, but are not limited to, being disposed on an upper portion of the cold trap body 12. For example, at least a portion (the middle portion shown in FIG. 2, i.e., the portion substantially parallel to the cold trap body 12) of the outlet pipe 14 and the inlet pipe 13 are connected (e.g., welded) side by side, so that the working fluid, while entering the inlet pipe 13, exchanges heat with the low-temperature working fluid discharged from the outlet pipe 14, thereby pre-cooling the working fluid before it enters the cold trap body 12.

[0046] According to an embodiment of the present disclosure, as shown in FIG. 2, the cold trap body 12 includes a first portion 121 adjacent to the cold head 3 and a second portion 122 away from the cold head 3. A material of the first portion 121 is different from a material of the second portion 122, and a thermal conductivity of the first portion 121 is higher than a thermal conductivity of the second portion 122.

[0047] According to an embodiment of the present disclosure, as shown in FIG. 2, the cold trap body 12 is provided with an adsorption material, and the adsorption material is at least filled in the first portion 121.

[0048] In an illustrative embodiment, as shown in FIG. 2, the first portion 121 (the lower portion shown in FIG. 2) of the cold trap body 12 and the second portion 122 (the upper portion shown in FIG. 2) of the cold trap body 12 are made of different materials. Specifically, the first portion 121 and the second portion 122 are integrally formed by, including but not limited to, welding, so that the first portion 121 and the second portion 122 have good sealing properties, thereby preventing the working fluid from leaking out of the cold trap body 12.

[0049] In a preferred embodiment, the first portion 121 includes, but is not limited to, being made of copper. Further, the second portion 122 includes, but is not limited to, being made of stainless steel. In such an implementation, copper has better thermal conductivity than stainless steel. Being mounted on the cold head 3, the first portion 121 may be quickly cooled by the cold head 3 to the first temperature, while the second portion 122 made of stainless steel and the pre-cooled inlet pipe 13 allow the working fluid to form a relatively uniform temperature gradient as it enters the cold trap body 12, thereby achieving stepwise cooling and making full use of the cold source.

[0050] In an illustrative embodiment, the adsorption material includes, but is not limited to, being filled in the first portion 121. Further, an end of the inlet pipe 13 located inside the cold trap body 12 is inserted into the bottom of the adsorption material, and an end of the outlet pipe 14 located inside the cold trap body 12 is located in the second portion 122, so that impurities in the working fluid (e.g., helium-3) passing through the adsorption material are sufficiently adsorbed by the adsorption material.

[0051] According to an embodiment of the present disclosure, as shown in FIG. 3, the desorption mechanism includes a heating assembly (not shown in the figures) and a first vacuum pump 6. The heating assembly is used to heat the cold trap body 12 to the second temperature (e.g., room temperature). The first vacuum pump 6 is in communication with the cold trap body 12 and is used to extract impurities desorbed from the cold trap body 12.

[0052] According to an embodiment of the present disclosure, not shown in the figures, the heating assembly is disposed in the cold head 3. The desorption mechanism further includes a temperature acquisition assembly (not shown) communicatively connected to the heating assembly, and used to acquire a temperature of the cold head 3 and/or the cold trap body 12.

[0053] In an illustrative embodiment, the heating assembly and/or the temperature acquisition assembly may be disposed in the cold head 3. The heating assembly includes, but is not limited to, any one of a resistance heater, a heating tape, a positive temperature coefficient (PTC) heater, a ceramic heater, a heat exchanger, and other heating assemblies used to heat the cold trap body 12 to the second temperature (e.g., room temperature). The temperature acquisition assembly includes, but is not limited to, any one of a platinum resistor (e.g., PT100 or PT1000), a thermocouple, a nickel resistance temperature sensor (i.e., NTC), a diode temperature sensor, and other temperature acquisition assemblies used to acquire the temperature of the cold trap body 12 under the first temperature (e.g., 77K). Specifically, because the cold trap body 12 is assembled with the cold head 3 and forms good thermal communication therewith, the temperature of the cold trap body 12 may be considered substantially the same as the temperature of the cold head 3. On this basis, the heating assembly and the temperature acquisition assembly being mounted on the cold head 3 may be considered to heat the cold trap body 12 and acquire its temperature.

[0054] According to an embodiment of the present disclosure, as shown in FIG. 3, the piping mechanism 5 further includes a second branch 52 disposed between the cold trap body 12 and the circulation pipeline 4. In response to the cut-off state of the first branch 51, the second branch 52 communicates the cold trap body 12 with the circulation pipeline 4, so as to allow working fluid remaining in the cold trap body 12 to flow back to the circulation pipeline 4.

[0055] In an illustrative embodiment, as shown in FIG. 3, the second branch 52 is disposed between the inlet end of the cold trap body 12 (the left end shown in FIG. 3) and the circulation pipeline 4 (the left end of the second branch 52, not shown). For example, a fourth valve (i.e., V4 as shown in FIG. 3) is provided on the second branch 52, and the interior of the second branch 52 is maintained at a negative pressure state. The negative pressure state of the second branch 52 is mainly achieved by a pump disposed between the second branch 52 and the circulation pipeline 4. For example, a molecular pump (or other pumps, not shown in the figures) may be disposed between the second branch 52 and the circulation pipeline 4. An end of the second branch 52 away from the fourth valve (V4) is disposed upstream of the molecular pump (or other pumps, not shown), so that under the suction of the molecular pump (or other pumps, not shown), the negative pressure state is formed in the second branch 52.

[0056] In an illustrative embodiment, as shown in FIG. 3, the piping mechanism 5 further includes a third branch 53. Specifically, the first vacuum pump 6 is disposed on the third branch 53. Further, a fifth valve (i.e., V5 as shown in FIG. 3) is provided between an inlet end of the first vacuum pump 6 and the inlet end of the cold trap body 12.

[0057] In a preferred embodiment, to facilitate control of various branches of the piping mechanism 5 and the circulation pipeline 4, the above-mentioned valves and pumps may be cooperatively controlled by a corresponding control terminal (e.g., a PLC, i.e., a programmable logic controller, a host computer, or other equipment). Based on the gas flow diagram shown in FIG. 3, the first valve (V1), the second valve (V2), the fourth valve (V4), the fifth valve (V5), and the sixth valve (V6) may be controlled to be closed when de-energized, and the third valve (V3) may be controlled to be open when de-energized.

[0058] In such an implementation, when the working fluid purification device is in the second mode, the second valve (V2) and the third valve (V3) are closed, so that the first branch 52 is in a cut-off state, and the working fluid circulates through the circulation pipeline 4 in the refrigeration apparatus. At this point, the fourth valve (V4) is opened. Through the negative pressure in the second branch 52, the working fluid (e.g., helium-3) remaining in the cold trap body flows back into the circulation pipeline 4 (or a working fluid source communicated with the circulation pipeline 4) to extract the working fluid until the gas pressure falls below a preset value (including, but not limited to, 10 mbar), after which the fourth valve (V4) is closed, thereby preventing waste of the working fluid. After the working fluid has been extracted, the fifth valve (V5) is opened, and the cold trap body 12 is slowly heated by the heating assembly to the second temperature (e.g., room temperature) and maintained stably for a preset time length (including, but not limited to, half an hour). Then, impurities desorbed from the adsorption material of the cold trap body 12 are extracted by the first vacuum pump 6 until the impurities are completely cleaned. After the impurities are completely cleaned, the fifth valve (V5) is closed, and the cold trap body 12 is cooled by the cold head 3 until it returns to the first temperature (e.g., 77K) and maintained stably for a preset time length (including, but not limited to, half an hour). Then, the second valve (V2) and the third valve (V3) are opened, and the first valve (V1) is closed, so that the working fluid purification device returns to the first mode of adsorbing impurities from the working fluid.

[0059] FIG. 5 is a partial enlarged view of the working fluid purification device shown in FIG. 1, showing an adapter ring.

[0060] In an illustrative embodiment, as shown in FIGS. 1 and 5, the working fluid purification device further includes a connection mechanism 2 disposed between the cold trap body 12 and the cold head 3. Specifically, the connection mechanism 2 includes a first flange 21 mounted on a lower end of the cold trap body 12, a second flange 23 mounted on an upper end of the cold head 3, and a sleeve located between the first flange 21 and the second flange 23. Further, the first flange 21, the second flange 23, and the sleeve define a chamber that is in communication with the vacuum cavity, so that under the action of the second vacuum pump 8, the chamber is also evacuated to a vacuum state, thereby maintaining thermal isolation at a connection position between the cold trap body 12 and the cold head 3. The first flange 21 and/or the second flange 23 include, but are not limited to, vacuum clamp flanges.

[0061] In an illustrative embodiment, as shown in FIG. 5, the connection mechanism 2 further includes an adapter ring 24. For example, the cold trap body 12 and the cold head 3 are connected via the adapter ring 24. The adapter ring 24 includes, but is not limited to, being made of copper.

[0062] FIG. 6 is a block diagram of a refrigeration system according to an illustrative embodiment of the present disclosure.

[0063] As shown in FIG. 6, based on the same concept, the present disclosure also provides a refrigeration system, including at least one refrigeration apparatus 9 to be purified, at least one working fluid purification device, and a second vacuum pump 8. The first branch 51 of the working fluid purification device is connected in parallel with the circulation pipeline 4 of each refrigeration apparatus 9, and the first branch and the circulation pipeline 4 are alternatively opened. The second vacuum pump 8 is in communication with the vacuum enclosure 11 of the working fluid purification device, and is used to evacuate the vacuum cavity to a vacuum state. The working fluid purification device is used to adsorb impurities in the working fluid in response to an open state of the first branch 51, and to desorb impurities from the cold trap body 12 of the working fluid purification device in response to a cut-off state of the first branch 51.

[0064] According to an embodiment of the present disclosure, as shown in FIG. 6, the refrigeration system includes a plurality of refrigeration apparatuses 9 connected in parallel with each other.

[0065] In an illustrative embodiment, as shown in FIG. 6, the refrigeration system includes, but is not limited to, four refrigeration apparatuses 9, namely a first refrigeration apparatus 91, a second refrigeration apparatus 92, a third refrigeration apparatus 93, and a fourth refrigeration apparatus 94 arranged in order from left to right in FIG. 6. Specifically, the refrigeration apparatuses (i.e., the first refrigeration apparatus 91, the second refrigeration apparatus 92, the third refrigeration apparatus 93, and the fourth refrigeration apparatus 94, each being provided with a separate circulation pipeline 4) are connected in parallel. Further, an inlet end for the working fluid and an outlet end for the working fluid of each refrigeration apparatus 9 are each in communication with a working fluid purification device. The refrigeration apparatus 9 includes, but is not limited to, a refrigerator, a pipeline communicated with the refrigerator, a working fluid source, a pump, valves, a detection assembly (e.g., a pressure gauge, a flow meter, a thermometer, and other metering devices used to acquire a state of the working fluid), and other assemblies used to circulate the working fluid between the refrigerator and an environment requiring cooling.

[0066] In such an implementation, impurities in a plurality of spatially close refrigeration apparatuses 9 may be cleaned (i.e., impurity removal) by a single working fluid purification device. Further, in an initial operation stage of the refrigeration apparatuses 9 (a stage in which the working fluid carries a relatively large amount of gas impurities), a single working fluid purification device may not be able to meet the adsorption requirement for a large amount of impurities. To this end, the plurality of refrigeration apparatuses 9 may be started up at different moments, so that the cold trap mechanism of the working fluid purification device is shared among the plurality of refrigeration apparatuses 9.

[0067] FIG. 7 is a block diagram of a refrigeration system according to another illustrative embodiment of the present disclosure, showing an embodiment with two working fluid purification devices.

[0068] According to an embodiment of the present disclosure, as shown in FIG. 7, the refrigeration system includes at least two working fluid purification devices, and the two working fluid purification devices are redundant to each other and are alternatively in communication with the refrigeration apparatus 9.

[0069] In an illustrative embodiment, two mutually independent working fluid purification devices may be provided in the refrigeration system. Specifically, each of the two working fluid purification devices may be connected to the plurality of refrigeration apparatuses 9 in the refrigeration system in the connection manner shown in FIG. 7.

[0070] In such an implementation, the two working fluid purification devices may be in communication with each refrigeration apparatus 9 in the refrigeration system, thereby being redundant to each other. That is, when one working fluid purification device is in the first mode of adsorbing impurities, the other is in a standby mode or a second mode of desorbing adsorbed impurities. In this way, the refrigeration system, in continuous operation, does not have a gap in which impurities may not be adsorbed, and may adapt to the application scenarios where a large amount of impurities is present in a gas source. Taking the application scenario of adsorbing impurities in a working fluid of a dilution refrigerator as an example, this may be applied to at least one of an initial operation state of the dilution refrigerator and an operation state in which a large amount of gas impurities is entrained due to a leak point in the circulation pipeline.

[0071] It should also be noted that directional terms used in the embodiments, such as "upper," "lower," "front," "rear," "left," "right," etc., are only used with reference to the orientation of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are denoted by the same or similar reference numerals. Conventional structures or constructions will be omitted when they may obscure the understanding of the present disclosure.

[0072] The embodiments of the present disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although various embodiments have been described separately above, this does not mean that measures in the various embodiments cannot be advantageously used in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and such substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. A working fluid purification device configured to purify a working fluid of a refrigeration apparatus, comprising:

a cold trap mechanism, comprising

a cold trap body mounted on a cold head of a first refrigerator, wherein the cold trap body is in thermal communication with the cold head, so as to be cooled by the cold head to a first temperature for adsorbing impurities;

a vacuum enclosure covering an outer side of the cold trap body, wherein the vacuum enclosure defines a vacuum cavity, and the vacuum cavity is configured to be evacuated to a vacuum state, so as to thermally isolate the cold trap body from an external environment;

a piping mechanism, comprising a first branch configured to connect the cold trap body in parallel with a circulation pipeline of a refrigeration apparatus to be purified, wherein the first branch and the circulation pipeline are alternatively opened; and

a desorption mechanism, configured to heat, in response to a cut-off state of the first branch, the cold trap body to a second temperature for desorbing the impurities, and extract the impurities from the cold trap body.

2. The purification device according to claim 1, wherein the desorption mechanism comprises:

a heating assembly configured to heat the cold trap body to the second temperature; and

a first vacuum pump in communication with the cold trap body, wherein the first vacuum pump is configured to extract the impurities desorbed from the cold trap body.

3. The purification device according to claim 2, wherein,

the heating assembly is disposed in the cold head; and

the desorption mechanism further comprises a temperature acquisition assembly communicatively connected to the heating assembly, wherein the temperature acquisition assembly is configured to acquire a temperature of the cold head and/or the cold trap body.

4. The purification device according to claim 1, wherein the piping mechanism further comprises a second branch disposed between the cold trap body and the circulation pipeline, and the second branch communicates the cold trap body with the circulation pipeline in response to the cut-off state of the first branch, so as to allow the working fluid remaining in the cold trap body to flow back to the circulation pipeline.

5. The purification device according to any one of claims 1 to 4, wherein,

the cold trap mechanism further comprises an inlet pipe and an outlet pipe, the inlet pipe is configured as an inlet end of the cold trap body, and the outlet pipe is configured as an outlet end of the cold trap body; and

the inlet pipe and the outlet pipe are arranged side by side and in thermal communication with each other.

6. The purification device according to any one of claims 1 to 4, wherein,

the cold trap body comprises a first portion close to the cold head and a second portion away from the cold head; and

a material of the first portion is different from a material of the second portion, and a thermal conductivity of the first portion is higher than a thermal conductivity of the second portion.

7. The purification device according to claim 6, wherein the cold trap body is provided with an adsorption material, and the adsorption material is at least filled in the first portion.

8. A refrigeration system, comprising:

at least one refrigeration apparatus to be purified;

at least one working fluid purification device according to any one of claims 1 to 7, wherein the first branch of the working fluid purification device is connected in parallel with a circulation pipeline of each of the at least one refrigeration apparatus to be purified, and the first branch and the circulation pipeline are alternatively opened; and

a second vacuum pump in communication with the vacuum enclosure of the working fluid purification device, wherein the second vacuum pump is configured to evacuate the vacuum cavity of the vacuum enclosure to the vacuum state,

wherein the working fluid purification device is configured to adsorb impurities in the working fluid in response to an open state of the first branch, and to desorb the impurities from the cold trap body of the working fluid purification device in response to the cut-off state of the first branch.

9. The refrigeration system according to claim 8, comprising a plurality of refrigeration apparatuses connected in parallel with each other.

10. The refrigeration system according to claim 8, comprising at least two working fluid purification devices, wherein the at least two working fluid purification devices are redundant to each other and are alternatively in communication with the refrigeration apparatus.

Drawing