Low-temperature constant-temperature cold source using latent heat of adsorption

Abstract

The application discloses a low-temperature constant-temperature cold source utilizing adsorption latent heat, which is provided with an adsorption container filled with an adsorbent and filled with a working gas, and utilizes the adsorption latent heat generated when the working gas is desorbed to provide the cold source. The low-temperature constant-temperature cold source utilizes the adsorption latent heat generated when the working gas is desorbed to provide the cold source for a cooling platform. The application does not have any active moving parts, and has the characteristic of no vibration; the adsorption of the working gas on the surface of the adsorbent can occur in a wide temperature range higher than the boiling point of the working gas, so that the cooling can be provided in a wide temperature range; the utilization of the adsorption latent heat as the cold source can cope with greater heat shock, has better temperature stability, and has the advantages of simple device structure, easy-to-obtain material, convenient operation, low cost and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cryogenic constant-temperature cold source, in particular to a cryogenic constant-temperature cold source using adsorption latent heat. BACKGROUND

[0002] Cryogenic constant-temperature environment is a necessary condition for the realization of low-temperature micro-nano processing, low-temperature in-situ microscopic observation, high-precision infrared imaging and superconducting calorimeter and other scientific technologies. However, these systems involving micro-nano precision processing and observation are very sensitive to mechanical vibration, so the cryogenic constant-temperature cold source providing the cryogenic constant-temperature environment has very high low-vibration requirements. On the other hand, in order to realize stable processing conditions and observation environments at different temperatures, it is very important for the cryogenic constant-temperature cold source to be able to flexibly provide cold energy in a large temperature range.

[0003] There are two general ways to obtain a cryogenic constant-temperature cold source: active cryogenic refrigerator cooling and low-temperature liquid cooling.

[0004] Active cryogenic refrigerators, such as Stirling-type refrigerators, pulse tube refrigerators, G-M-type refrigerators, throttling refrigerators, etc., can easily obtain refrigeration in a large temperature range. However, these refrigerators often have active moving parts such as compressors and rotating valves, which have large mechanical vibrations when running, and cannot meet the requirements of micro-nano processing / observation systems for system mechanical vibration.

[0005] Low-temperature liquid cooling technology uses low-temperature liquids such as liquid nitrogen and liquid helium to provide low-temperature constant-temperature cold source by evaporation and heat absorption. The system generally has low mechanical vibration. However, low-temperature liquid cooling can only provide the temperature points of the boiling points of the liquid, such as 4K (-269℃) for liquid helium, 20K (-253℃) for liquid hydrogen, 27K (-246℃) for liquid neon, and 77K (-196℃) for liquid nitrogen, and cannot flexibly adjust the temperature of the cryogenic constant-temperature cold source in a large temperature range.

[0006] Therefore, the above-mentioned traditional cryogenic constant-temperature cold source technology cannot meet the requirements of micro-nano processing / observation systems. SUMMARY

[0007] In order to provide a vibration-free, adjustable-temperature cryogenic constant-temperature cold source for the fields of micro-nano processing, microscopic observation, high-precision optical imaging, etc., the present application proposes a cryogenic constant-temperature cold source using adsorption latent heat, and adopts the following technical solutions:

[0008] A cryogenic constant-temperature cold source using adsorption latent heat, an adsorption container is provided, the adsorption container is filled with an adsorbent, and is filled with a working gas. The adsorption latent heat generated by the desorption of the working gas is used to provide a cooling platform with a cold source.

[0009] The adsorbent is a high specific surface area physical adsorbent material, such as activated carbon, organic metal grid material, molecular sieve, silica gel, etc.; the adsorbent can adsorb a large amount of working gas under high pressure and low temperature conditions; by controlling the working gas to flow out of the adsorption container, the pressure in the container is reduced, the working gas adsorbed on the surface of the adsorbent is desorbed, and the gas desorption will absorb heat; the latent heat of adsorption generated by the gas desorption provides a non-vibration cold source, and provides refrigeration for the cooling platform.

[0010] The working gas can be helium, hydrogen, neon, nitrogen or commonly used low-temperature working gas such as methane; according to the different cooling temperature zones (T L ~T H ) required by the cold source, it is appropriate to select a gas with a boiling point T BP,Gas lower than the lowest temperature T L of the required cooling temperature zone, a larger adsorption amount, and a larger latent heat of adsorption as the working gas.

[0011] The adsorption of the working gas on the surface of the adsorbent can occur in a wide temperature range above the boiling point of the working gas, so the adsorption container can provide cooling in a wide temperature range; using the latent heat of adsorption as a cold source can cope with greater thermal shock and has better temperature stability.

[0012] In order to realize continuous and long-term cooling, the adsorption container can be arranged in parallel and alternately.

[0013] Further, a low-temperature constant-temperature cold source using adsorption latent heat includes: a working gas storage tank, a gas supply valve, an exhaust valve, a gas supply and exhaust pipe, an exhaust port, an adsorption container, a cooling platform, a low-temperature liquid storage tank, a cooling platform, a thermal switch I, a pressure gauge, a thermometer I, a thermometer II and a heater I.

[0014] The working gas storage tank is connected to the room temperature end of the gas supply and exhaust pipe through the gas supply valve, and the low temperature end of the gas supply and exhaust pipe is connected to the adsorption container; the room temperature end of the gas supply and exhaust pipe is connected to the exhaust port through the exhaust valve; the room temperature end of the gas supply and exhaust pipe is provided with a pressure gauge; the adsorption container is provided with a thermometer II and a heater I.

[0015] The low-temperature liquid storage tank is connected to the cooling platform through the thermal switch I; the low-temperature liquid storage tank is in thermal connection with the adsorption container; the adsorption container is in thermal connection with the cooling platform; the cooling platform is provided with a thermometer I, and the sample to be cooled is installed on the cooling platform.

[0016] The cooling platform is made of a metal with good thermal conductivity, such as aluminum, oxygen-free copper, etc.; the cooling platform is provided with an interface in thermal connection with the low-temperature liquid storage tank and the adsorption container, and is also provided with an interface for installing the sample to be cooled.

[0017] The gas supply valve is a stop valve, which is opened during the gas filling process to allow the high-pressure working gas in the working gas tank to fill the adsorption container, and is closed when the adsorption container provides cold energy; the gas exhaust valve is a control valve or a metering valve with precise flow control, which controls the slow exhaust of the working gas in the adsorption container by adjusting the opening degree when the adsorption container provides cold energy.

[0018] The low-temperature liquid tank contains low-temperature liquid, such as liquid helium, liquid hydrogen, liquid neon, or liquid nitrogen, etc.; the low-temperature liquid tank provides a non-vibration primary cold source by using the latent heat generated by the evaporation of the low-temperature liquid.

[0019] The thermal connection can realize the transfer of cold energy, which is used to conduct the cold energy of the low-temperature liquid tank to the adsorption container and the cooling platform as pre-cooling, and also transfer the cold energy generated by the adsorption container to the cooling platform to provide cooling for the sample.

[0020] The thermal switch is a thermal control device that can realize the disconnection or connection of the thermal connection, and there are many different types according to different principles, such as mechanical thermal switch, gas gap thermal switch, superconducting thermal switch, etc.; the function of the thermal switch I is to disconnect the thermal connection between the cooling platform and the low-temperature liquid tank when the adsorption container is working, to isolate the thermal influence of the low-temperature liquid tank on the cooling platform, to reduce the heating amount required by the heater I to control the temperature of the cooling platform, and to reduce the consumption of the low-temperature liquid in the low-temperature liquid tank.

[0021] As a preferred embodiment, a thermal switch II is further provided between the low-temperature liquid tank and the adsorption container, which functions to disconnect the thermal connection between the adsorption container and the low-temperature liquid tank when the adsorption container is working, thereby reducing the heating amount required by the heater I to control the temperature of the cooling platform and reducing the consumption of the low-temperature liquid in the low-temperature liquid tank.

[0022] As a preferred embodiment, a heater II is provided on the gas supply and exhaust pipe, and a thermometer III is further provided on the room temperature end of the gas supply and exhaust pipe chamber, which functions to heat the exhaust cold gas to room temperature when the adsorption container is exhausting, to avoid the cold gas freezing the room temperature components, such as pressure gauges and exhaust valves, to a too low temperature, which affects the normal work of the room temperature components or even damages them.

[0023] As a preferred embodiment, a flow controller I is provided between the gas supply valve and the room temperature end of the gas supply and exhaust chamber, and a flow controller II is provided between the exhaust interface and the exhaust valve; the purpose of setting the flow controller I is to more accurately control the gas filling amount and to realize a faster gas filling process; the purpose of setting the flow controller II is to more accurately and in real time control the exhaust amount, so as to reduce the heating amount of the heater I for temperature control, reduce the exhaust rate, and prolong the cooling time under the premise of meeting the constant temperature control.

[0024] As a further preferred, a vacuum pump is further provided between the exhaust valve and the exhaust interface, which can further evacuate the gas in the adsorption container, thereby prolonging the cooling time.

[0025] The working principle of the above low-temperature constant-temperature cold source is that a low-temperature liquid storage tank is used as a non-vibration primary cold source, the heat switches I, II and III are closed, the adsorption container, the cooling platform and the sample installed on the cooling platform are pre-cooled to an initial low-temperature T ini , by heat conduction. ini , which is slightly lower than T L ; while pre-cooling the adsorption container, the gas supply valve is opened and the exhaust valve is closed, the working gas in the working gas storage tank is filled into the adsorption container, the room-temperature working gas filled into the adsorption container is cooled to a low temperature, and a large amount of working gas is adsorbed to the surface of the adsorbent in the adsorption container as the pressure in the adsorption container increases; when the pressure gauge connected to the room-temperature end of the gas supply and exhaust pipe reaches a preset pressure p ini , the gas supply valve is closed, and as the gas in the adsorption container and the gas supply and exhaust pipe is further cooled and adsorbed to the surface of the adsorbent, the pressure in the adsorption container is further reduced; when the pressure tends to be stable, the gas supply valve can be opened again for gas filling, and after the above gas filling process is repeated for several times, the pressure of the adsorption container tends to the preset pressure p ini , and the temperature is stable at T ini ; after the adsorption container is filled with gas, the heat switches I and II are disconnected, the heater I on the adsorption container is turned on, the temperature of the cooling platform is controlled to a set cooling temperature T set , and the exhaust valve is opened, so that the gas in the adsorption container is slowly exhausted; as the pressure in the adsorption container gradually decreases, the gas is desorbed from the surface of the adsorbent, and the desorption process absorbs heat, thereby generating cold energy to maintain the constant low temperature of the cooling platform.

[0026] The beneficial effects of the present application are as follows:

[0027] Low-temperature micro-nano machining, low-temperature in-situ microscopic observation, high-precision infrared imaging and superconducting calorimeter technology usually require a low-temperature constant-temperature cold source. However, these systems involving micro-nano precision machining and observation are very sensitive to mechanical vibration, so the low-temperature constant-temperature cold source providing a low-temperature constant-temperature environment has very high low-vibration requirements. On the other hand, in order to realize stable machining conditions and observation environment at different temperatures, it is very crucial whether the low-temperature constant-temperature cold source can flexibly provide cold energy in a large temperature range. At present, the general low-temperature constant-temperature cold source is obtained by active low-temperature refrigeration machine cooling and low-temperature liquid cooling, the former has a large vibration due to the active moving parts, and the latter cannot flexibly adjust the temperature of the low-temperature constant-temperature cold source in a large temperature range, so they cannot meet the needs of the above technical fields for a low-temperature constant-temperature cold source without vibration and capable of adjusting the temperature in a large range.

[0028] In order to meet the above requirements, the application innovatively proposes a low-temperature constant-temperature cold source using adsorption latent heat, which uses the adsorption latent heat generated by the desorption of working gas to provide a cold source for the cooling platform. The technical scheme has no active moving parts and has the characteristics of no vibration; the adsorption of working gas on the surface of the adsorbent can occur in a wide temperature range above the boiling point of the working gas, so it can provide cooling in a wide temperature range; using adsorption latent heat as a cold source can cope with greater thermal shock and has better temperature stability; and the device of the application has simple structure, easy-to-obtain materials, convenient operation and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The first embodiment of the low-temperature constant-temperature cold source using adsorption latent heat is a schematic diagram.

[0030] Figure 2 The second embodiment of the low-temperature constant-temperature cold source using adsorption latent heat is a schematic diagram.

[0031] Figure 3 The third embodiment of the low-temperature constant-temperature cold source using adsorption latent heat is a schematic diagram.

[0032] The correspondence between the reference signs and the component names is as follows:

[0033] 1. Working gas storage tank; 2. Gas supply valve; 3. Exhaust valve; 4. Gas supply and exhaust pipe; 5. Exhaust port; 6. Adsorption container; 7. Cooling platform, 8. Low-temperature liquid storage tank, 9. Thermal switch I, 10. Pressure gauge, 11. Temperature gauge I, 12. Temperature gauge II, 13. Heater I, 14. Sample to be cooled, 15. Thermal switch II, 16. Heater II, 17. Temperature gauge III, 18. Flow controller I, 19. Flow controller II, 20. Vacuum pump, 21. Gas supply valve a, 22. Gas supply valve b, 23. Gas supply main valve, 31. Exhaust valve a, 32. Exhaust valve b, 61. Adsorption container a, 62. Adsorption container b, 101. Pressure gauge a, 102. Pressure gauge b, 121. Temperature gauge II-a, 122. Temperature gauge II-b, 131. Heater I-a, 132. Heater I-b, 151. Thermal switch II-a, 152. Thermal switch II-b, 153. Thermal switch III-a, 154. Thermal switch III-b, 400. Counterflow heat exchanger, 411. Gas supply and exhaust pipe room temperature end pipeline a, 412. Gas supply and exhaust pipe low-temperature end pipeline a, 421. Gas supply and exhaust pipe room temperature end pipeline b, 422. Gas supply and exhaust pipe low-temperature end pipeline b. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. However, the described embodiments are only some, not all, of the embodiments of the present invention. Other embodiments based on the embodiments of the present invention, without creative effort by those skilled in the art, are all within the scope of protection of the present invention.

[0035] Example 1:

[0036] like Figure 1 As shown, a low-temperature constant-temperature cold source utilizing latent heat of adsorption includes a working fluid storage tank (1), a gas supply valve (2), an exhaust valve (3), a gas supply and exhaust pipe (4), an exhaust port (5), an adsorption container (6), a cooling platform (7), a low-temperature liquid storage tank (8), a thermal switch I (9), a pressure gauge (10), a thermometer I (11), a thermometer II (12), and a heater I (13).

[0037] The working medium storage tank (1) is connected to the room temperature end of the gas supply and exhaust pipe (4) via the gas supply valve (2), and the low temperature end of the gas supply and exhaust pipe (4) is connected to the adsorption container (6); the room temperature end of the gas supply and exhaust pipe (4) is connected to the exhaust port (5) via the exhaust valve (3); a pressure gauge (10) is provided at the room temperature end of the gas supply and exhaust pipe (4); a thermometer II (12) and a heater I (13) are provided on the adsorption container (6).

[0038] The cryogenic liquid storage tank (8) is connected to the cooling platform (7) via a thermal switch I (9); the cryogenic liquid storage tank (8) is thermally connected to the adsorption container (6); the adsorption container (6) is thermally connected to the cooling platform (7); a thermometer I (11) is provided on the cooling platform (7), and the sample (14) to be cooled is installed on the cooling platform (7).

[0039] The steps and principles for providing a low-temperature constant-temperature cold source to the sample under test using this embodiment are as follows:

[0040] Step 1: Turn on the thermal switch I (9), and the cryogenic liquid storage tank (8) precools the cooling platform (7) and adsorption container (6), and the sample to be cooled (14) is also precooled at the same time; finally, the cooling platform (7), adsorption container (6) and the sample to be cooled (14) are precooled to the same temperature T as the cryogenic liquid in the cryogenic liquid storage tank (8). ini =T BP,Gas .

[0041] Step 2: When the adsorption container (6) is pre-cooled, close the exhaust valve (3) and open the gas supply valve (2) to fill the working gas in the working gas tank (1) into the adsorption container (6). The room temperature working gas is cooled to low temperature in the adsorption container (6), and a large amount of working gas is adsorbed to the surface of the adsorbent in the adsorption container (6) as the pressure in the adsorption container (6) increases.

[0042] Step 3: When the pressure gauge (10) connected to the room temperature end of the gas supply and exhaust pipe (4) reaches the preset pressure p ini , close the gas supply valve (2). As the gas in the adsorption container (6) and the gas supply and exhaust pipe (4) is further cooled and adsorbed to the surface of the adsorbent, the pressure in the adsorption container (6) will further decrease. When the pressure tends to be stable, the gas supply valve (2) can be opened again for charging. After repeating the above charging process several times, the pressure in the adsorption container (6) tends to the preset pressure p ini , and the temperature stabilizes at T ini .

[0043] Step 4: After the adsorption container (6) is filled, disconnect the thermal switch I (9) and open the heater I (13) on the adsorption container (6) to control the temperature of the cooling platform (7) to the set cooling temperature T set . At the same time, open the exhaust valve (3) to slowly exhaust the gas in the adsorption container (6). As the pressure in the adsorption container (6) gradually decreases, the gas is desorbed from the surface of the adsorbent, which absorbs heat during the desorption process and generates cold energy to maintain the constant low temperature of the cooling platform.

[0044] Example 2:

[0045] As shown in Figure 2 , a low-temperature constant-temperature cold source using adsorption latent heat is provided. The difference between this embodiment and Example 1 is that the low-temperature constant-temperature cold source further includes a thermal switch II (15), a heater II (16), a thermometer III (17), a flow controller I (18), a flow controller II (19), and a vacuum pump (20). The low-temperature liquid tank (8) and the adsorption container (6) are provided with a thermal switch II (15); the gas supply and exhaust pipe (4) is provided with a heater II (16), and the room temperature end of the gas supply and exhaust pipe (4) is further provided with a thermometer III (17); the gas supply valve (2) and the room temperature end of the gas supply and exhaust pipe (4) are provided with a flow controller I (18), and the exhaust port and the exhaust valve are provided with a flow controller II; the flow controller II (19) and the exhaust port (5) are further provided with a vacuum pump (20).

[0046] The difference between this embodiment and Example 1 in the operation steps is as follows:

[0047] In step 1, the thermal switch II (15) is opened to connect the low temperature liquid tank (8) with the adsorption vessel (6) to pre-cool the adsorption vessel (6) and the working gas filled therein.

[0048] The mass of the working gas filled in the adsorption vessel (6) in steps 2 and 3 and the initial pressure p ini and the initial temperature T ini are recorded by the flow controller I (18) to quickly estimate the mass m ini of the working gas actually needed to be filled in the adsorption vessel (6) for the next operation, so that in step 3, the flow controller I (18) can be set to automatically shut down after passing the mass m ini of the working gas, and the filling process can be completed in one single operation.

[0049] In step 4, the thermal switch II (15) is opened when the low temperature constant temperature cold source provides constant temperature cooling for the sample to be cooled; the exhaust flow of the flow controller II (19) is set to stabilize the cooling platform (7) at the set cooling temperature T set , and the heat compensation power required by the heater I (13) is as small as possible; when the pressure of the adsorption vessel (6) is lower than about 2 bar, the vacuum pump (20) is opened to further extend the working time of the adsorption vessel (6); during the exhaust process of the adsorption vessel (6), the heater II (16) is opened to heat the low temperature working gas exhausted from the adsorption vessel (6) to room temperature (measured by the temperature meter III (17) at the room temperature end of the gas supply and exhaust pipe), so as to protect the downstream exhaust valve (3), the flow controller II (19) and the vacuum pump (20) from being damaged by the low temperature working gas.

[0050] Example 3:

[0051] In order to realize continuous and long time cooling, the adsorption vessel can be set to two in parallel and work alternately. For example, Figure 3As shown, a low-temperature constant-temperature cold source using adsorption latent heat, comprising a working medium storage tank (1), an exhaust interface (5), a cooling platform (7), a low-temperature liquid storage tank (8), a thermal switch I (9), a thermometer I (11), a flow controller I (18), a flow controller II (19), a vacuum pump (20), a gas supply valve a (21), a gas supply valve b (22), a gas supply total valve (23), an exhaust valve a (31), an exhaust valve b (32), an adsorption container a (61), an adsorption container b (62), a pressure gauge a (101), a pressure gauge b (102), a thermometer II-a (121), a thermometer II-b (122), a heater I-a (131), a heater I-b (132), a thermal switch II-a (151), a thermal switch II-b (152), a thermal switch III-a (153), a thermal switch III-b (154), a counterflow heat exchanger (400), a supply and exhaust pipe room temperature end pipeline a (411), a supply and exhaust pipe low-temperature end pipeline a (412), a supply and exhaust pipe room temperature end pipeline b (421), and a supply and exhaust pipe low-temperature end pipeline b (422).

[0052] The working medium storage tank (1) is connected with the inlet of the flow controller I (18) through the gas supply valve (23); the outlet of the flow controller I (18) is divided into two parallel paths, one path is connected with the supply and exhaust pipe room temperature end pipeline a (411) through the gas supply valve a (21), and the other path is connected with the supply and exhaust pipe room temperature end pipeline b (421); the supply and exhaust pipe room temperature end pipeline a (411) is provided with a pressure gauge a (101) and is connected with the hot end of the first path in the counterflow heat exchanger (400); the supply and exhaust pipe room temperature end pipeline b (421) is provided with a pressure gauge b (102) and is connected with the hot end of the second path in the counterflow heat exchanger (400); the supply and exhaust pipe room temperature end pipeline a (411) and the supply and exhaust pipe room temperature end pipeline b (421) are further connected with the flow controller II (19), the vacuum pump (20) and the exhaust interface (5) in sequence through the exhaust valve a (31) and the exhaust valve b (32) respectively; the cold end of the first path in the counterflow heat exchanger (400) is connected with the adsorption container a (61) through the supply and exhaust pipe low temperature end pipeline a (412), and the cold end of the second path in the counterflow heat exchanger (400) is connected with the adsorption container b (62) through the supply and exhaust pipe low temperature end pipeline b (422); the adsorption container a (61) is provided with a thermometer II-a (121) and a heater I-a (131), and the adsorption container b (62) is provided with a thermometer II-b (122) and a heater I-b (132); the adsorption container a (61) is connected with the low temperature liquid storage tank (8) through the thermal switch II-a (151) and is connected with the cooling platform (7) through the thermal switch III-a (153); the adsorption container b (62) is connected with the low temperature liquid storage tank (8) through the thermal switch II-b (152) and is connected with the cooling platform (7) through the thermal switch III-b (154); the low temperature liquid storage tank (8) is connected with the cooling platform (7) through the thermal switch I (9); the cooling platform (7) is provided with a thermometer I (11), and the sample to be cooled (14) is installed on the cooling platform (7).

[0053] The steps and principles for providing a low-temperature constant-temperature cold source for the sample to be measured are as follows:

[0054] Step 1: turn on the thermal switch I (9), the thermal switch II-a (151) and the thermal switch II-b (152), and turn off the thermal switch III-a (153) and the thermal switch III-b (154); the low temperature liquid storage tank (8) pre-cools the cooling platform (7), the adsorption container a (61) and the adsorption container b (62), and the sample to be cooled (14) is also pre-cooled; finally, the cooling platform (7), the adsorption container a (61), the adsorption container b (62) and the sample to be cooled (14) are pre-cooled to the same temperature T ini =T BP,Gas .

[0055] Step 2: While pre-cooling adsorption vessel a (61), close exhaust valve a (31) and exhaust valve b (32), close supply valve b (22), set the accumulated mass of flow controller I (18) to zero, then open supply valve a (21), charge the working gas in working gas tank (1) into adsorption vessel a (61), the room temperature working gas is cooled to low temperature in adsorption vessel a (61), as the pressure in adsorption vessel a (61) increases, a large amount of working gas is adsorbed to the surface of the adsorbent material in adsorption vessel a (61).

[0056] Step 3: When the pressure gauge a (101) reaches the preset pressure p ini , close the supply valve a (21), as the gas in the adsorption vessel a (61) and its connecting pipeline is further cooled and adsorbed to the surface of the adsorbent, the pressure in the adsorption vessel a (61) will further decrease, when the pressure tends to be stable, the supply valve a (21) can be opened again for charging, after repeating the above charging process several times, the pressure of the adsorption vessel a (61) tends to the preset pressure p ini , and the temperature stabilizes at T ini ; record the accumulated mass of flow controller I (18) as m ini ;

[0057] Step 4: After completing the charging of adsorption vessel a (61), disconnect thermal switch I (9) and thermal switch II-a (151), and open thermal switch III-a (153); open heater I-a (131) to heat and control the temperature of the cooling platform (7) to the set cooling temperature T set , at the same time, close the supply valve a (21), open the exhaust valve a (31), set the exhaust flow of flow controller II (19) so that the cooling platform (7) stabilizes at the set cooling temperature T set , at the same time, the heat compensation power required by heater I-a (131) is as small as possible; when the reading of pressure gauge a (101) is less than 2 bar, open the vacuum pump (20); when adsorption vessel a (61) provides constant low temperature cooling to the cooling platform (7), open the supply valve b (22), set the supply flow of flow controller I (18) consistent with the exhaust flow of flow controller II (19); at this time, the working gas in the working gas tank (1) is first pre-cooled by the second path of the counterflow heat exchanger (400) by the working gas discharged from adsorption vessel a (61) from the first path, then charged into adsorption vessel b (62), as the pressure in adsorption vessel b (62) increases, a large amount of working gas is adsorbed to the surface of the adsorbent material in adsorption vessel b (62).

[0058] Step 5: When the working gas in the adsorption container a (61) is almost exhausted, open the thermal switch II-a (151) and the thermal switch III-b (154), and disconnect the thermal switch II-b (152) and the thermal switch III-a (153); close the exhaust valve a (31) and the gas supply valve b (22), and open the gas supply valve a (21) and the exhaust valve b (32), switch the adsorption container a (61) to the gas charging state, and switch the adsorption container b (62) full of working gas to the working state, and connect with the cooling platform (7) to continue to provide constant temperature low temperature cooling, and the alternating switching can provide continuous constant temperature low temperature cooling.

Claims

1. A low-temperature constant-temperature cold source using latent heat of adsorption, characterized by, The low-temperature constant-temperature cold source is provided with an adsorption container filled with an adsorbent and filled with a working gas, and the adsorption latent heat generated by desorption of the working gas is used to provide the cold source; The system comprises a working gas storage tank, a gas supply valve, a gas exhaust valve, a gas supply and exhaust pipe, a gas exhaust interface, an adsorption container, a cooling platform, a low-temperature liquid storage tank, a thermal switch I, a pressure gauge, a thermometer I, a thermometer II and a heater I; The working gas storage tank is connected to the room-temperature end of the gas supply and exhaust pipe through the gas supply valve, the low-temperature end of the gas supply and exhaust pipe is connected to the adsorption container, the room-temperature end of the gas supply and exhaust pipe is connected to the gas exhaust interface through the gas exhaust valve, the room-temperature end of the gas supply and exhaust pipe is provided with a pressure gauge, the adsorption container is provided with a thermometer II and a heater I; The low-temperature liquid storage tank is connected to the cooling platform through the thermal switch I, the low-temperature liquid storage tank is thermally connected to the adsorption container, the adsorption container is thermally connected to the cooling platform, and the cooling platform is provided with a thermometer I, and a sample to be cooled is installed on the cooling platform.

2. The low-temperature constant-temperature cold source using latent heat of adsorption according to claim 1, characterized by, The adsorption container is provided in multiple parallel connections and works alternately.

3. The low-temperature constant-temperature cold source using latent heat of adsorption according to claim 1, characterized by, The working gas is helium, hydrogen, neon, nitrogen or methane.

4. The low-temperature constant-temperature cold source using latent heat of adsorption according to claim 1, characterized by, The adsorbent is activated carbon, organic metal mesh material, molecular sieve or silica gel.

5. The low-temperature constant-temperature cold source using latent heat of adsorption according to claim 1, characterized by, A thermal switch II is arranged between the low-temperature liquid storage tank and the adsorption container.

6. The low-temperature constant-temperature cold source using latent heat of adsorption according to claim 5, characterized by, The thermal switch I and the thermal switch II are mechanical thermal switches, gas gap thermal switches or superconducting thermal switches.

7. The low-temperature constant-temperature cold source using latent heat of adsorption according to any one of claims 1 to 6, characterized by, The gas supply and exhaust pipe is provided with a heater II, and the room-temperature end of the gas supply and exhaust pipe is further provided with a thermometer III.

8. The low-temperature constant-temperature cold source using latent heat of adsorption according to any one of claims 1 to 6, characterized by, A flow controller I is arranged between the gas supply valve and the room-temperature end of the gas supply and exhaust pipe, and a flow controller II is arranged between the gas exhaust interface and the gas exhaust valve.

9. The low-temperature constant-temperature cold source using latent heat of adsorption according to any one of claims 1 to 6, characterized by, A vacuum pump is further arranged between the gas exhaust valve and the gas exhaust interface.

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