A dilution refrigerator with built-in cold trap for sample preparation of two-dimensional thin film materials

Abstract

The present invention discloses a dilution refrigerator with a built-in cold trap for preparing two-dimensional thin film material samples, comprising a shell, an air inlet pipe is provided at the top of the shell, an air outlet pipe is installed on the side of the shell, an airtight cover is detachably installed at the bottom of the shell, and a filtering mechanism is provided inside the shell; the filtering mechanism comprises a gas distribution vertical pipe and a cylindrical filter cover, and the top of the gas distribution vertical pipe is connected to the air inlet pipe. In the present invention, before the gas enters the dilution refrigerator, it is first evenly dispersed by the gas distribution vertical pipe and the partition guide plate, and then preliminarily filtered by the primary filter screen on the cylindrical filter cover, effectively removing large particle impurities in the gas, and the adsorbent outside the cylindrical filter cover further absorbs residual impurities and steam, and the secondary filter screen in the air outlet filter realizes secondary filtration, further improving the purity of the gas and reducing the blockage of the circulation pipeline, so as to ensure the normal operation of the dilution refrigerator.

Description

Technical Field

[0001] The invention relates to the technical field of dilution refrigerators, and in particular to a dilution refrigerator with a built-in cold trap for preparing two-dimensional thin film material samples. Background Art

[0002] The principle of ultra-low temperature refrigeration of the independently developed ultra-high-precision molecular beam epitaxy-ultra-low temperature scanning tunneling microscope combined system is 3He-4He dilution refrigeration. Generally, the steam is extracted from the liquid phase of the mixing chamber, and the steam is sent back to the system through the pump group through the pressure difference to be used as liquid helium again. In this process, the extracted steam will gradually heat up to room temperature, and then cool down to ultra-low temperature (<40 mK) again. During the entire cycle, if there is a small amount of gas leakage in the gas line, the impurities that may exist in the pipeline are likely to be frozen in the low-temperature part of the pipeline, thereby blocking the gas line.

[0003] Therefore, it is necessary to add a cold trap at the air inlet end of the dilution refrigerator. The Chinese invention patent with patent number CN102743894B proposes a cold trap which does not have the function of filtering impurity gases.

[0004] To this end, the present invention solidifies the impurity gas by low temperature, so that the impurity gas is filtered by the first-stage filter and the second-stage filter and adsorbed by the adsorbent, reducing the blockage of the circulation pipeline and ensuring the normal operation of the dilution refrigerator. Summary of the invention

[0005] In order to solve the problems mentioned in the above background technology, the present invention provides a dilution refrigerator with a built-in cold trap for preparing two-dimensional thin film material samples.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A dilution refrigerator with a built-in cold trap for preparing two-dimensional thin film material samples, comprising a shell, an air inlet pipe is arranged at the top of the shell, an air outlet pipe is installed at the side of the shell, an airtight cover is detachably installed at the bottom of the shell, and a filtering mechanism is arranged inside the shell;

[0008] The filtering mechanism comprises a gas distribution vertical pipe and a cylindrical filter cover. The top of the gas distribution vertical pipe is connected to the air inlet pipe. A plurality of partition guide plates are fixed to the outside of the gas distribution vertical pipe. Refrigerant flows inside the partition guide plates. An air outlet is provided on the gas distribution vertical pipe between two adjacent partition guide plates.

[0009] The cylindrical filter cover is sleeved on the outside of the partition guide plate, and a primary filter screen is provided on the cylindrical filter cover at a position corresponding to the air outlet;

[0010] The outside of the cylindrical filter cover in the shell is filled with adsorbent.

[0011] Preferably, a plurality of the air outlet pipes are provided, and the plurality of air outlet pipes are evenly distributed around the shell and connected to the air inlet end of the dilution refrigerator through pipelines.

[0012] Preferably, an air outlet filter is installed between the air outlet pipe and the housing, and a secondary filter screen is installed in the air outlet filter.

[0013] Preferably, the bottom end of the shell is fixed to the airtight cover by a buckle, and a plurality of buckles are provided, and the plurality of buckles are evenly distributed around the shell in a ring shape.

[0014] Preferably, the cylindrical filter cover is rotatably mounted inside the shell via an annular guide rail, a first gear ring is fixed to the top of the cylindrical filter cover, a first rotating motor is fixed to the top of the shell, a first gear is fixed to the output shaft of the first rotating motor, and the first gear is meshed with the first gear ring.

[0015] Preferably, a vertically arranged threaded rod is installed on the outside of the gas distribution vertical pipe near the top position by rotating through a bracket. The number of the threaded rods is the same as the dividing guide plates, and the threaded rods extend between adjacent dividing guide plates. Special-shaped scrapers are also provided between adjacent dividing guide plates. The two sides of the special-shaped scrapers are in sliding contact with the two dividing guide plates respectively, and the threaded rods penetrate the special-shaped scrapers through threaded holes.

[0016] Preferably, a second gear is fixed to the top of the threaded rod, a second gear ring is rotatably installed on the outside of the gas distribution vertical pipe, multiple second gears are meshed with the second gear ring, a second rotating motor is fixed to the top of the outer shell, and the output shaft of the second rotating motor is fixedly connected to the top of one of the second gears.

[0017] Preferably, a lower sealing plate is fixed to the bottom end of the special-shaped scraper blade via a connecting vertical shaft, and the top end of the lower sealing plate is a slope structure.

[0018] Preferably, a deflection channel is provided inside the partition guide plate, adjacent partition guide plates are connected end to end through a refrigerant series flow tube, and the first partition guide plate and the last partition guide plate are respectively connected to a refrigerant inlet pipe and a refrigerant outlet pipe.

[0019] Preferably, the dividing guide plate is a curved wave-shaped structure.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. Before the gas enters the dilution refrigerator, it is first evenly dispersed by the gas distribution vertical pipe and the partition guide plate, and then preliminarily filtered through the primary filter on the cylindrical filter cover, effectively removing large particle impurities in the gas. The adsorbent outside the cylindrical filter cover further absorbs residual impurities and steam. The secondary filter in the air outlet filter realizes secondary filtration, further improving the purity of the gas and reducing the blockage of the circulation pipeline, so as to ensure the normal operation of the dilution refrigerator.

[0022] 2. The cylindrical filter cover can rotate automatically through the drive of the annular guide rail and the rotary motor. Combined with the scraper function of the partition guide plate, it can realize active cleaning of the inside of the cylindrical filter cover, reduce the accumulation of impurities, improve the cleaning efficiency and the long-term operation stability of the equipment. The special-shaped scraper between the partition guide plates is driven by the threaded rod to move up and down, effectively scraping off the impurities on the guide plate, and quickly discharging the impurities through the inclined design of the lower sealing plate, reducing the frequency and difficulty of manual maintenance.

[0023] 3. The partition guide plate adopts a curved wave-shaped structure with a baffle channel inside. Through the series flow of the refrigerant, efficient cooling of the gas is achieved. This design not only increases the contact area between the refrigerant and the gas, improves the heat exchange efficiency, but also reduces the risk of local overheating through the uniform dispersion of the gas. The cooled gas can flow through the primary filter more evenly, improving the filtration efficiency and the utilization rate of the filter, and further improving the purity of the gas.

[0024] 4. The detachable design between the outer shell and the airtight cover makes it easy to clean the cylindrical filter cover and the partition guide plate, and to replace the adsorbent, thus reducing maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A perspective view of the present invention;

[0027] Figure 2 A top view of the present invention;

[0028] Figure 3 It is a schematic diagram of the internal structure of the air outlet filter of the present invention;

[0029] Figure 4 It is a schematic diagram of the internal structure of the housing of the present invention;

[0030] Figure 5 A schematic diagram showing the connection relationship between the partition guide plate and the gas distribution vertical pipe of the present invention from a first viewing angle;

[0031] Figure 6 A schematic diagram showing the connection relationship between the partition guide plate and the gas distribution vertical pipe of the present invention from a second viewing angle;

[0032] Figure 7 is a cross-sectional view of a partition guide plate of the present invention;

[0033] Figure 8 It is an enlarged detail view of the position of the annular guide rail of the present invention;

[0034] Fig. 9 This is a schematic diagram of the distribution position of the special-shaped scraper of the present invention;

[0035] Fig.10 It is a three-dimensional diagram of the cylindrical filter cover of the present invention from an upward perspective;

[0036] Fig.11 It is a schematic diagram of the internal structure of the housing of the present invention from a top view;

[0037] Fig.12 It is a schematic diagram of the matching relationship between the special-shaped scraper and the dividing guide plate of the present invention (the special-shaped scraper is at the highest point);

[0038] Fig.13 It is a schematic diagram of the matching relationship between the special-shaped scraper and the dividing guide plate of the present invention (the special-shaped scraper is at the lowest point);

[0039] In the figure: outer shell 1, air inlet pipe 101, air outlet filter 102, secondary filter 1021, air outlet pipe 103, airtight cover 104, buckle 105, annular guide rail 106, first gear ring 107, first rotating motor 108, first gear 109, second rotating motor 110, gas distribution vertical pipe 2, partition guide plate 201, air outlet 202, baffle channel 203, refrigerant series flow pipe 204, refrigerant inlet pipe 205, refrigerant outlet pipe 206, cylindrical filter cover 3, primary filter 301, second gear ring 4, threaded rod 401, second gear 402, special-shaped scraper 403, connecting vertical shaft 404, lower blocking plate 405. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] Reference Figure 1-13 A dilution refrigerator with a built-in cold trap for preparing two-dimensional thin film material samples, comprising a housing 1, an air inlet pipe 101 is provided at the top of the housing 1, an air outlet pipe 103 is installed on the side of the housing 1, an airtight cover 104 is detachably installed at the bottom of the housing 1, and a filtering mechanism is provided inside the housing 1;

[0043] The filtering mechanism includes a gas distribution vertical pipe 2 and a cylindrical filter cover 3. The top of the gas distribution vertical pipe 2 is connected to the air inlet pipe 101. A plurality of partition guide plates 201 are fixed to the outside of the gas distribution vertical pipe 2. The interior of the partition guide plates 201 is filled with refrigerant. An air outlet 202 is provided on the gas distribution vertical pipe 2 between two adjacent partition guide plates 201.

[0044] The cylindrical filter cover 3 is sleeved on the outside of the partition guide plate 201, and a primary filter screen 301 is provided on the cylindrical filter cover 3 at a position corresponding to the air outlet 202;

[0045] After the gas enters the cold trap through the air inlet pipe 101, it first enters the gas distribution vertical pipe 2. In the vertical pipe 2, the gas is evenly dispersed by multiple partition guide plates 201 and is preliminarily cooled by the refrigerant inside the partition guide plates 201. The cooled gas is ejected from the outlet 202 of the gas distribution vertical pipe 2. There are multiple outlet pipes 103, and the multiple outlet pipes 103 are evenly distributed around the shell 1 and are connected to the air inlet end of the dilution refrigerator through a pipeline. The gas passes through the primary filter 301 on the cylindrical filter cover 3 to further remove impurity particles in the gas. Since the dispersed gas can flow through the primary filter 301 more evenly, the primary filter 301 is also an arc-shaped structure, so that the utilization efficiency of the primary filter 301 is higher and the filtering effect is improved.

[0046] The outside of the cylindrical filter cover 3 in the outer shell 1 is filled with adsorbent. The gas after the first-stage filtration then enters the outer area of ​​the cylindrical filter cover 3 and contacts with the filled adsorbent. The adsorbent further absorbs the residual impurities and steam in the gas, ensuring that the gas finally entering the dilution refrigerator is highly pure.

[0047] Among them, an air outlet filter 102 is installed between the air outlet pipe 103 and the shell 1, and a secondary filter screen 1021 is installed in the air outlet filter 102. The gas absorbed by the adsorbent is filtered again through the secondary filter screen 1021 and then flows out from the cold trap, achieving a secondary filtering effect.

[0048] Example 2

[0049] Reference Figure 1-13The difference between this embodiment and the embodiment 1 is that the bottom end of the housing 1 is fixed to the airtight cover 104 by a buckle 105, and there are multiple buckles 105, and the multiple buckles 105 are evenly distributed around the housing 1 in an annular shape;

[0050] The airtight cover 104 is used to seal the outer shell 1 . Due to the detachable design of the airtight cover 104 , it is convenient to clean the primary filter 301 and to replace the adsorbent in the outer shell 1 .

[0051] Example 3

[0052] Reference Figure 1-13 The difference between this embodiment and the first embodiment is that the cylindrical filter cover 3 is rotatably mounted inside the housing 1 through the annular guide rail 106, a first gear ring 107 is fixed to the top of the cylindrical filter cover 3, a first rotary motor 108 is fixed to the top of the housing 1, a first gear 109 is fixed to the output shaft of the first rotary motor 108, and the first gear 109 is meshed with the first gear ring 107;

[0053] When the first rotating motor 108 is turned on, the cylindrical filter cover 3 can be driven to rotate through the engagement of the first gear 109 and the first gear ring 107. At this time, the partition guide plate 201 can act as a scraper to scrape off the impurities accumulated inside the cylindrical filter cover 3, thereby achieving the purpose of active cleaning and improving the cleaning efficiency.

[0054] Example 4

[0055] Reference Figure 1-13 The difference between this embodiment and the embodiment 3 is that a vertically arranged threaded rod 401 is rotatably installed on the outside of the gas distribution vertical pipe 2 near the top through a bracket, the number of the threaded rod 401 is the same as the number of the dividing guide plates 201, and the threaded rod 401 extends between adjacent dividing guide plates 201, and a special-shaped scraper 403 is further arranged between adjacent dividing guide plates 201, and both sides of the special-shaped scraper 403 are in sliding contact with the two dividing guide plates 201 respectively, and the threaded rod 401 penetrates the special-shaped scraper 403 through a threaded hole;

[0056] When the threaded rod 401 rotates, the special-shaped scraper 403 can only slide up and down because it is clamped between the two partition guide plates 201, thereby driving the special-shaped scraper 403 to move up and down, so that the impurities accumulated on the partition guide plates 201 can be scraped and cleaned.

[0057] Among them, a second gear 402 is fixed to the top of the threaded rod 401, a second gear ring 4 is rotatably installed on the outside of the gas distribution vertical pipe 2, and multiple second gears 402 are meshed with the second gear ring 4. A second rotating motor 110 is fixed to the top of the housing 1, and the output shaft of the second rotating motor 110 is fixedly connected to the top of one of the second gears 402;

[0058] In order to drive the multiple threaded rods 401 to rotate synchronously, it is only necessary to turn on the second rotating motor 110. The second rotating motor 110 can drive one of the second gears 402 to rotate, and then drive the multiple threaded rods 401 to rotate synchronously through the engagement of the second gear 402 with the second gear ring 4, and then drive the multiple special-shaped scrapers 403 to rise and fall synchronously.

[0059] The bottom end of the special-shaped scraper 403 is fixed with a lower blocking plate 405 by connecting the vertical shaft 404, and the top end of the lower blocking plate 405 is an inclined structure;

[0060] After the impurities scraped off by the special-shaped scraper 403 fall to the top of the lower sealing plate 405, since the top of the lower sealing plate 405 is a sloped structure, the impurities will not stay on the top of the lower sealing plate 405, but will slide downward due to gravity and eventually fall to the outside of the outer shell 1, which is convenient for the rapid discharge of impurities.

[0061] Example 5

[0062] Reference Figure 1-13 The difference between this embodiment and embodiment 1 is that a baffle channel 203 is provided inside the partition guide plate 201, adjacent partition guide plates 201 are connected end to end through a refrigerant series flow pipe 204, and the first partition guide plate 201 and the last partition guide plate 201 are respectively connected with a refrigerant inlet pipe 205 and a refrigerant outlet pipe 206, and the partition guide plate 201 is a curved wave-shaped structure;

[0063] The refrigerant flows in through the refrigerant inlet pipe 205, flows in series in the deflection channels 203 of each partition guide plate 201, and finally flows out from the refrigerant outlet pipe 206. The gas can be cooled by heat exchange, thereby solidifying the impurity gas and reducing the temperature of the airflow, thereby alleviating the thermal load of the system.

[0064] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0065] In the present invention, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] The control method of the present invention is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by technicians in this field. The provision of power is also common knowledge in this field. The present invention is mainly used to protect mechanical devices, so the present invention will no longer explain the control method and circuit connection in detail.

[0067] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A dilution refrigerator with a built-in cold trap for preparing two-dimensional thin film material samples, comprising a housing (1), an air inlet pipe (101) being provided at the top of the housing (1), an air outlet pipe (103) being installed at the side of the housing (1), and a gas-tight cover (104) being detachably installed at the bottom of the housing (1), characterized in that: A filtering mechanism is provided inside the housing (1); The filtering mechanism comprises a gas distribution vertical pipe (2) and a cylindrical filter cover (3); the top end of the gas distribution vertical pipe (2) is connected to the air inlet pipe (101); a plurality of partition guide plates (201) are fixed to the outside of the gas distribution vertical pipe (2); a refrigerant flows inside the partition guide plates (201); and a gas outlet (202) is provided on the gas distribution vertical pipe (2) between two adjacent partition guide plates (201); The cylindrical filter cover (3) is sleeved on the outside of the partition guide plate (201), and a primary filter screen (301) is provided on the cylindrical filter cover (3) at a position corresponding to the air outlet (202); The outside of the cylindrical filter cover (3) inside the housing (1) is filled with an adsorbent; A vertically arranged threaded rod (401) is rotatably mounted on the outside of the gas distribution vertical pipe (2) near the top end thereof through a bracket, the number of the threaded rods (401) being the same as the number of the dividing guide plates (201), and the threaded rods (401) extending between adjacent dividing guide plates (201), and a special-shaped scraper (403) being further arranged between adjacent dividing guide plates (201), the two sides of the special-shaped scraper (403) respectively being in sliding contact with the two dividing guide plates (201), and the threaded rod (401) passing through the special-shaped scraper (403) through a threaded hole.

2. The dilution refrigerator with built-in cold trap for preparing two-dimensional thin film material samples according to claim 1, characterized in that: A plurality of the air outlet pipes (103) are provided, and the plurality of air outlet pipes (103) are evenly distributed around the outer shell (1) and connected to the air inlet end of the dilution refrigerator through pipelines.

3. The dilution refrigerator with built-in cold trap for preparing two-dimensional thin film material samples according to claim 2, characterized in that: An air outlet filter (102) is installed between the air outlet pipe (103) and the housing (1), and a secondary filter screen (1021) is installed in the air outlet filter (102).

4. The dilution refrigerator with built-in cold trap for preparing two-dimensional thin film material samples according to claim 1, characterized in that: The bottom end of the shell (1) is fixed to the airtight cover (104) via a buckle (105), and a plurality of buckles (105) are provided. The plurality of buckles (105) are evenly distributed in a ring shape around the shell (1).

5. The dilution refrigerator with built-in cold trap for preparing two-dimensional thin film material samples according to claim 1, characterized in that: The cylindrical filter cover (3) is rotatably mounted inside the housing (1) via an annular guide rail (106); a first gear ring (107) is fixed to the top of the cylindrical filter cover (3); a first rotating motor (108) is fixed to the top of the housing (1); a first gear (109) is fixed to the output shaft of the first rotating motor (108); and the first gear (109) meshes with the first gear ring (107).

6. The dilution refrigerator with built-in cold trap for preparing two-dimensional thin film material samples according to claim 1, characterized in that: A second gear (402) is fixed to the top of the threaded rod (401), a second gear ring (4) is rotatably mounted on the outside of the gas distribution vertical pipe (2), a plurality of second gears (402) are all meshed with the second gear ring (4), a second rotating motor (110) is fixed to the top of the housing (1), and an output shaft of the second rotating motor (110) is fixedly connected to the top of one of the second gears (402).

7. The dilution refrigerator with built-in cold trap for preparing two-dimensional thin film material samples according to claim 6, characterized in that: A lower blocking plate (405) is fixed to the bottom end of the special-shaped scraper (403) via a connecting vertical shaft (404), and the top end of the lower blocking plate (405) is a sloped structure.

8. The dilution refrigerator with built-in cold trap for preparing two-dimensional thin film material samples according to claim 1, characterized in that: The partition guide plate (201) is provided with a deflection channel (203) inside, and adjacent partition guide plates (201) are connected end to end via a refrigerant series flow pipe (204), and the first partition guide plate (201) and the last partition guide plate (201) are respectively connected to a refrigerant inlet pipe (205) and a refrigerant outlet pipe (206).

9. The dilution refrigerator with built-in cold trap for preparing two-dimensional thin film material samples according to claim 8, characterized in that: The dividing guide plate (201) is a curved wave-shaped structure.

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