CN119123697B

CN119123697B - A dilution refrigerator with built-in cold trap for sample preparation of two-dimensional thin film materials

Info

Publication number: CN119123697B
Application number: CN202411591260.0A
Authority: CN
Inventors: 张伟; 陈亚光; 常凯; 林海城
Original assignee: Beijing Institute Of Quantum Information Science
Current assignee: Beijing Institute Of Quantum Information Science
Priority date: 2024-11-08
Filing date: 2024-11-08
Publication date: 2025-01-21
Anticipated expiration: 2044-11-08
Also published as: CN119123697A

Abstract

The invention discloses a built-in cold trap of a dilution refrigerator for preparing a two-dimensional film material sample, which comprises a shell, wherein the top end of the shell is provided with an air inlet pipe, the side surface of the shell is provided with an air outlet pipe, the bottom end of the shell is detachably provided with an airtight cover, the interior of the shell is provided with a filtering mechanism, the filtering mechanism comprises a gas distribution vertical pipe and a cylindrical filtering cover, and the top end of the gas distribution vertical pipe is communicated with the air inlet pipe. Before entering the dilution refrigerator, the gas is uniformly dispersed through the gas distribution vertical pipes and the separation guide plates, and is subjected to primary filtration through the primary filter screen on the cylindrical filter cover, so that large particle impurities in the gas are effectively removed, the adsorbent outside the cylindrical filter cover further absorbs residual impurities and steam, secondary filtration is realized through the secondary filter screen in the air outlet filter, the purity of the gas is further improved, the occurrence of blockage of a circulating pipeline is reduced, and the normal operation efficiency of the dilution refrigerator is ensured.

Description

Built-in cold trap of dilution refrigerator for preparing two-dimensional film material sample

Technical Field

The invention relates to the technical field of dilution refrigerators, in particular to a built-in cold trap of a dilution refrigerator for preparing a two-dimensional film material sample.

Background

The principle of ultralow temperature refrigeration of the independently-developed ultrahigh true molecular beam epitaxy-ultralow temperature scanning tunnel microscope combined system is 3He-4He dilution refrigeration. The vapor is typically pumped from the liquid phase of the mixing chamber and returned to the system through the pump stack by differential pressure to be reused. The vapor extracted in this process gradually warms to room temperature and then drops again to very low temperatures (< 40 mK a). In the whole circulation process, a small amount of air leakage exists in the air passage, and possibly existing miscellaneous air in the pipeline is likely to be frozen in a low-temperature part of the pipeline, so that the air passage is blocked.

Therefore, a cold trap is required to be added at the air inlet end of the dilution refrigerator, and the Chinese patent No. CN102743894B discloses a cold trap which does not have the function of filtering impurity gas.

Therefore, the invention solidifies the impurity gas at low temperature, so that the impurity gas is filtered by the first-stage filter screen and the second-stage filter screen and is adsorbed by the adsorbent, thereby reducing the occurrence of blockage of the circulating pipeline and ensuring the normal operation effect of the dilution refrigerator.

Disclosure of Invention

In order to solve the problems mentioned in the background art, the invention provides a built-in cold trap of a dilution refrigerator for preparing a two-dimensional film material sample.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

the built-in cold trap of the dilution refrigerator for preparing the two-dimensional film material sample comprises a shell, wherein the top end of the shell is provided with an air inlet pipe, the side surface of the shell is provided with an air outlet pipe, the bottom end of the shell is detachably provided with an airtight cover, and the interior of the shell is provided with a filtering mechanism;

The filtering mechanism comprises a gas distribution vertical pipe and a cylindrical filtering cover, the top end of the gas distribution vertical pipe is communicated with the air inlet pipe, a plurality of separation guide plates are fixed outside the gas distribution vertical pipe, refrigerant is introduced into the separation guide plates, and an air outlet is formed in the position, located between two adjacent separation guide plates, of the gas distribution vertical pipe;

The cylindrical filter cover is sleeved outside the separation guide plate, and a first-stage filter screen is arranged on the cylindrical filter cover at a position corresponding to the air outlet;

the outer part of the inner cylinder filter cover of the shell is filled with adsorbent.

Preferably, the air outlet pipes are arranged in a plurality, and the air outlet pipes are uniformly distributed around the shell and are connected to the air inlet end of the dilution refrigerator through pipelines.

Preferably, an air outlet filter is arranged between the air outlet pipe and the shell, and a secondary filter screen is arranged in the air outlet filter.

Preferably, the bottom end of the shell and the airtight cover are fixed through buckles, the buckles are provided with a plurality of buckles, and the buckles are annularly and uniformly distributed around the shell.

Preferably, the cylinder filter cover is rotatably installed in the shell through the annular guide rail, a first toothed ring is fixed at the top end of the cylinder filter cover, a first rotating motor is fixed at the top end of the shell, a first gear is fixed on an output shaft of the first rotating motor, and the first gear is meshed with the first toothed ring.

Preferably, the outside that is close to the top position of gas distribution standpipe rotates through the support and installs the threaded rod of vertical setting, and the number of threaded rod is the same with separating the guide plate, and the threaded rod extends to between the adjacent guide plate that separates, still is equipped with special-shaped scraper blade between the adjacent guide plate that separates, the both sides of special-shaped scraper blade respectively with two separation guide plate sliding contact, the threaded rod runs through special-shaped scraper blade through the screw hole.

Preferably, the top of threaded rod is fixed with the second gear, and the outside of gas distribution standpipe rotates installs the second ring gear, and a plurality of second gears all mesh with the second ring gear, and the top of shell is fixed with the second rotating electrical machines, and the output shaft of second rotating electrical machines and the top fixed connection of one of them second gear.

Preferably, the bottom of the special-shaped scraping plate is fixed with a lower plugging plate through a connecting vertical shaft, and the top end of the lower plugging plate is of an inclined plane structure.

Preferably, a baffling channel is arranged in the separation guide plate, adjacent separation guide plates are communicated end to end through a refrigerant serial flow pipe, and a refrigerant inlet pipe and a refrigerant outlet pipe are respectively connected to the first separation guide plate and the last separation guide plate.

Preferably, the separation guide plate has a curved wave-shaped structure.

Compared with the prior art, the invention has the beneficial effects that:

1. Before entering the dilution refrigerator, the gas is uniformly dispersed through the gas distribution vertical pipes and the separation guide plates, and is subjected to preliminary filtration through the primary filter screen on the cylindrical filter cover, so that large-particle impurities in the gas are effectively removed, the residual impurities and steam are further absorbed by the adsorbent outside the cylindrical filter cover, secondary filtration is realized through the secondary filter screen in the air outlet filter, the purity of the gas is further improved, the occurrence of blockage of a circulating pipeline is reduced, and the normal operation effect of the dilution refrigerator is ensured.

2. The cylinder filter cover is driven by the annular guide rail and the rotating motor, can automatically rotate, combines the scraping plate function of the separation guide plate, realizes active cleaning of the inside of the cylinder filter cover, reduces impurity accumulation, and improves cleaning efficiency and long-term operation stability of equipment. The special-shaped scraping plates between the separation guide plates are driven by the threaded rods to lift and move, impurities on the guide plates are effectively scraped, the impurities are rapidly discharged through the inclined plane design of the lower plugging plate, and the frequency and difficulty of manual maintenance are reduced.

3. The separation guide plate adopts a bending wave-shaped structure, a baffling channel is arranged in the separation guide plate, and the high-efficiency cooling of gas is realized through the serial flow of refrigerants. The design not only increases the contact area of the refrigerant and the gas and improves the heat exchange efficiency, but also reduces the risk of local overheating through the uniform dispersion of the gas, and the cooled gas can more uniformly flow through the primary filter screen, so that the filtering efficiency and the utilization rate of the filter screen are improved, and the purity of the gas is further improved.

4. The detachable design between shell and the airtight cover is convenient for clean drum filter cover, separation guide plate, is convenient for change the adsorbent, has reduced maintenance cost.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a perspective view of the present invention;

FIG. 2 is a top view of the present invention;

FIG. 3 is a schematic view of the internal structure of the air outlet filter according to the present invention;

FIG. 4 is a schematic view of the internal structure of the housing of the present invention;

FIG. 5 is a schematic view of a first view of a connection between a partition baffle and a gas distribution standpipe according to the present invention;

FIG. 6 is a schematic view of a second view of the connection between a partition baffle and a gas distribution standpipe according to the present invention;

FIG. 7 is a cross-sectional view of a partition baffle of the present invention;

FIG. 8 is an enlarged detail view of the circular rail position of the present invention;

FIG. 9 is a schematic view of the distribution position of the special-shaped scraping plate of the invention;

FIG. 10 is a perspective view of a cylindrical filter housing of the present invention from above;

FIG. 11 is a schematic top view of the internal structure of the housing of the present invention;

FIG. 12 is a schematic diagram of the fit relationship between the profiled screed and the separating baffle of the present invention (profiled screed is at the highest point state);

FIG. 13 is a schematic diagram showing the cooperation relationship between the special-shaped scraper and the separation baffle (the special-shaped scraper is positioned at the lowest point state);

In the figure, a shell 1, an air inlet pipe 101, an air outlet filter 102, a secondary filter 1021, an air outlet pipe 103, an airtight cover 104, a buckle 105, an annular guide rail 106, a first toothed ring 107, a first rotary motor 108, a first gear 109, a second rotary motor 110, a gas distribution vertical pipe 2, a separation guide plate 201, an air outlet 202, a baffle channel 203, a refrigerant serial pipe 204, a refrigerant introducing pipe 205, a refrigerant introducing pipe 206, a cylindrical filter cover 3, a primary filter screen 301, a second toothed ring 4, a threaded rod 401, a second gear 402, a special-shaped scraper 403, a connecting vertical shaft 404 and a lower plugging plate 405 are shown.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Example 1

Referring to fig. 1-13, a built-in cold trap of a dilution refrigerator for preparing a two-dimensional film material sample comprises a shell 1, wherein an air inlet pipe 101 is arranged at the top end of the shell 1, an air outlet pipe 103 is arranged on the side surface of the shell 1, an airtight cover 104 is detachably arranged at the bottom end of the shell 1, and a filtering mechanism is arranged in the shell 1;

The filtering mechanism comprises a gas distribution vertical pipe 2 and a cylindrical filtering cover 3, the top end of the gas distribution vertical pipe 2 is communicated with the air inlet pipe 101, a plurality of separation guide plates 201 are fixed outside the gas distribution vertical pipe 2, refrigerants are led into the separation guide plates 201, and an air outlet 202 is formed in the position, located between two adjacent separation guide plates 201, of the gas distribution vertical pipe 2;

the cylindrical filter cover 3 is sleeved outside the separation guide plate 201, and a first-stage filter screen 301 is arranged on the cylindrical filter cover 3 at a position corresponding to the air outlet 202;

After the gas enters the cold trap through the air inlet pipe 101, firstly, the gas enters the gas distribution vertical pipe 2, in the vertical pipe 2, the gas is uniformly dispersed by a plurality of separation guide plates 201 and is primarily cooled by refrigerants in the separation guide plates 201, the cooled gas is sprayed out from the air outlets 202 of the gas distribution vertical pipe 2, the air outlet pipes 103 are provided with a plurality of air outlet pipes 103, the air outlet pipes 103 are uniformly distributed around the shell 1 and are connected to the air inlet end of the dilution refrigerator through pipelines, and the air passes through the first-stage filter screen 301 on the cylindrical filter cover 3, so that impurity particles in the gas are further removed, and the dispersed gas can more uniformly flow through the first-stage filter screen 301, and the first-stage filter screen 301 is of an arc structure, so that the utilization efficiency of the first-stage filter screen 301 is higher, and the filtering effect is improved.

The outside of the cylindrical filter housing 3 inside the shell 1 is filled with the adsorbent, the gas after the first-stage filtration then enters the outer region of the cylindrical filter housing 3 and contacts with the filled adsorbent, and the adsorbent further absorbs residual impurities and steam in the gas, so that the gas finally entering the dilution refrigerator is ensured to be highly pure.

Wherein, a gas outlet filter 102 is arranged between the gas outlet pipe 103 and the shell 1, a secondary filter screen 1021 is arranged in the gas outlet filter 102, and the gas absorbed by the adsorbent flows out from the cold sink after being filtered again by the secondary filter screen 1021, thereby achieving the effect of secondary filtration.

Example 2

Referring to fig. 1 to 13, the difference between the present embodiment and embodiment 1 is that the bottom end of the housing 1 and the airtight cover 104 are fixed by the snap fasteners 105, and the snap fasteners 105 are provided in plurality, and the plurality of snap fasteners 105 are uniformly distributed around the housing 1 in a ring shape;

The airtight cover 104 is used for sealing the housing 1, and due to the detachable design of the airtight cover 104, the primary filter screen 301 is convenient to clean, and the adsorbent in the housing 1 can be conveniently replaced.

Example 3

Referring to fig. 1 to 13, the present embodiment differs from embodiment 1 in that a cylindrical filter housing 3 is rotatably mounted inside a housing 1 through an annular guide rail 106, a first toothed ring 107 is fixed to the top end of the cylindrical filter housing 3, a first rotary motor 108 is fixed to the top end of the housing 1, a first gear 109 is fixed to an output shaft of the first rotary motor 108, and the first gear 109 is engaged with the first toothed ring 107;

When the first rotary motor 108 is started, the first gear 109 is meshed with the first toothed ring 107 to drive the cylindrical filter cover 3 to rotate, and at the moment, the separation guide plate 201 can serve as a scraping plate to scrape impurities accumulated in the cylindrical filter cover 3, so that the purpose of active cleaning is achieved, and the cleaning efficiency is improved.

Example 4

Referring to fig. 1-13, the difference between this embodiment and embodiment 3 is that the outer portion of the gas distribution standpipe 2 near the top end is rotatably provided with vertically arranged threaded rods 401 through a bracket, the number of the threaded rods 401 is the same as that of the separation deflectors 201, the threaded rods 401 extend between adjacent separation deflectors 201, a special-shaped scraping plate 403 is further provided between the adjacent separation deflectors 201, two sides of the special-shaped scraping plate 403 are respectively in sliding contact with the two separation deflectors 201, and the threaded rods 401 penetrate through the special-shaped scraping plates 403 through threaded holes;

When the threaded rod 401 rotates, the special-shaped scraping plate 403 can only slide up and down due to the fact that the special-shaped scraping plate 403 is clamped between the two separation guide plates 201, and then the special-shaped scraping plate 403 can be driven to move up and down, so that impurities accumulated on the separation guide plates 201 can be scraped and cleaned.

The top end of the threaded rod 401 is fixed with a second gear 402, the outer part of the gas distribution vertical pipe 2 is rotatably provided with a second toothed ring 4, a plurality of second gears 402 are meshed with the second toothed ring 4, the top end of the shell 1 is fixed with a second rotating motor 110, and an output shaft of the second rotating motor 110 is fixedly connected with the top end of one of the second gears 402;

in order to drive the plurality of threaded rods 401 to rotate synchronously, only the second rotating motor 110 is required to be started, the second rotating motor 110 can drive one of the second gears 402 to rotate, and then the second gears 402 are meshed with the second toothed ring 4 to drive the plurality of threaded rods 401 to rotate synchronously, so that the plurality of special-shaped scraping plates 403 are driven to move synchronously in a lifting mode.

Wherein, the bottom end of the special-shaped scraping plate 403 is fixed with a lower plugging plate 405 through a connecting vertical shaft 404, and the top end of the lower plugging plate 405 is of an inclined plane structure;

After the impurity scraped off by the special-shaped scraping plate 403 falls to the top end of the lower plugging plate 405, the top end of the lower plugging plate 405 is of an inclined surface structure, so that the impurity is guaranteed not to stay at the top end of the lower plugging plate 405, and the impurity can slide down due to gravity and finally fall to the outside of the shell 1, and the impurity is conveniently and rapidly discharged.

Example 5

Referring to fig. 1-13, the difference between this embodiment and embodiment 1 is that a baffle channel 203 is provided in the partition baffle 201, adjacent partition baffles 201 are connected end to end through a refrigerant serial pipe 204, and a refrigerant inlet pipe 205 and a refrigerant outlet pipe 206 are respectively connected to the first partition baffle 201 and the last partition baffle 201, and the partition baffles 201 have a curved wave structure;

The refrigerant flows in through the refrigerant introducing pipe 205 and flows in series in the baffling channels 203 of the separation guide plates 201, finally flows out from the refrigerant eduction pipe 206, and can cool the gas in a heat exchange mode, thereby solidifying the impurity gas, reducing the temperature of the air flow and reducing the heat load of the system.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

In the present invention, unless explicitly stated or limited otherwise, the terms "disposed," "mounted," "connected," "secured" and the like are to be construed broadly, as they are, for example, fixedly connected, detachably connected, or integrally formed, mechanically connected, directly connected, indirectly connected through intermediaries, or in communication between two elements or in interaction with each other. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

The control mode of the invention is automatically controlled by the controller, the control circuit of the controller can be realized by simple programming of a person skilled in the art, the supply of power also belongs to common knowledge in the art, and the invention is mainly used for protecting a mechanical device, so the invention does not explain the control mode and circuit connection in detail.

The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art, who is within the scope of the present invention, should make equivalent substitutions or modifications according to the technical scheme of the present invention and the inventive concept thereof, and should be covered by the 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 an airtight 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. A dilution refrigerator with a built-in cold trap for preparing two-dimensional thin film material samples according to claim 1, characterized in that: a plurality of the outlet pipes (103) are provided, and the plurality of outlet pipes (103) are evenly distributed around the outer shell (1) and connected to the air inlet end of the dilution refrigerator through a pipeline.

3. A dilution refrigerator with a 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. A dilution refrigerator with a 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) by a buckle (105), and there are multiple buckles (105), and the multiple buckles (105) are evenly distributed in a ring around the shell (1).

5. A dilution refrigerator with a 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) through 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) is meshed with the first gear ring (107).

6. A dilution refrigerator with a 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), multiple 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 the output shaft of the second rotating motor (110) is fixedly connected to the top of one of the second gears (402).

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

8. A dilution refrigerator with a built-in cold trap for preparing two-dimensional thin film material samples according to claim 1, characterized in that: a deflection 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 tube (204), and the first partition guide plate (201) and the last partition guide plate (201) are respectively connected to a refrigerant inlet tube (205) and a refrigerant outlet tube (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 partition guide plate (201) is a curved wave-shaped structure.