CN114396825A - A two cavity formula heat-conduction switch and utmost point cryogenic equipment for utmost point cryogenic equipment - Google Patents
A two cavity formula heat-conduction switch and utmost point cryogenic equipment for utmost point cryogenic equipment Download PDFInfo
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- CN114396825A CN114396825A CN202111658473.7A CN202111658473A CN114396825A CN 114396825 A CN114396825 A CN 114396825A CN 202111658473 A CN202111658473 A CN 202111658473A CN 114396825 A CN114396825 A CN 114396825A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
- F28F2013/005—Thermal joints
- F28F2013/008—Variable conductance materials; Thermal switches
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
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Abstract
The invention discloses a two-cavity heat conduction switch for cryogenic equipment and the cryogenic equipment, wherein the two-cavity heat conduction switch for the cryogenic equipment comprises: the upper fixing plate, the lower fixing plate, the outer cavity wall and the inner cavity wall; the outer cavity wall is arranged between the upper fixing plate and the lower fixing plate, and a closed cavity, namely an outer cavity, is formed by the upper fixing plate, the lower fixing plate and the outer cavity; an external cavity heat conducting device is arranged in the external cavity; the inner cavity wall is arranged between the upper fixing plate and the lower fixing plate, a closed cavity, namely an inner cavity, is formed by the upper fixing plate, the lower fixing plate and the inner cavity wall, and the inner cavity wall is arranged inside the outer cavity wall; an internal cavity heat conduction device is arranged in the internal cavity. According to the invention, the active thermal switch and the passive thermal switch are combined, and the thermal switches in two different temperature ranges are combined, so that different heat conduction effects in a high-temperature region and a low-temperature region can be achieved, higher heat conduction efficiency can be obtained in the high-temperature region, and the low-temperature system can be cooled more quickly in the high-temperature region.
Description
Technical Field
The invention relates to the field of low-temperature switches, in particular to a two-cavity heat conduction switch for cryogenic equipment and the cryogenic equipment.
Background
With the rise of quantum computing, countries in the world have a large number of layouts in the research and development of quantum computing; in material science, the quantum behavior of new materials at extremely low temperatures is extensively studied by condensed physicists in various countries around the world; in the detector field, new forms of high resolution photon and ray detectors are being developed by various countries. Whether it is a quantum computer, condensed state physical research or a novel detector, the research carried out has all demands on the extremely low temperature environment provided by the dilution refrigerator.
The problems of large equipment, long temperature rise and fall period and complex operation are faced by the dilution refrigerator at present. The problem with long ramping periods can be ameliorated in the industry by using suitable thermal switches. The thermal switch is a heat-conducting switch, and in the equipment cooling process, a high-temperature area needing rapid cooling is turned on, so that heat at the bottom of the equipment is transferred to a cold head of the equipment at the highest speed. When the temperature reaches low temperature and the refrigeration mode of the equipment is changed, the thermal switch is required to be closed, and the thermal connection between the lowest temperature area of the equipment and the cold head with the slightly higher upper temperature is disconnected. The thermal switches currently used include mechanical thermal switches, gas gap thermal switches, superconducting thermal switches, graphite thermal switches, and memory alloy thermal switches.
The mechanical thermal switch adopts two smooth and softer heat-conducting metal surfaces for contact heat transfer, usually the surfaces are plated with gold copper, the two metal surfaces are tightly contacted by applying force through external driving, the external driving force is a component for controlling electromagnetic driving by manpower or engineering, and the contact and non-contact of the two metal surfaces are controlled to achieve the purpose of heat transfer on and off. However, the mechanical thermal switch adds a moving part to the refrigerator environment, and the reliability in long-term use is unknown in consideration of the influence of deformation due to temperature change.
The gas gap type thermal switch is one of the most widely used thermal switches at present. The thermal switch is connected between the cold end and the hot end through a sealing tube, air is filled in the sealing tube, heat is conducted through internal gas, and the switch is in an 'on' state; gas is pumped out of the sealed tube or is absorbed into the adsorbate, so that the tube is in a vacuum state, the heat conduction of the sealed tube is poor, and the thermal switch is in an off state.
The superconducting type thermal switch utilizes the characteristic of poor heat conduction of the superconductor, after the superconductor in the switch enters a superconducting state, the switch is in an off state, the superconductor is quenched and becomes good in heat conduction through micro-heating, and the switch enters the on state.
The shape memory alloy thermal switch can be designed according to the characteristics of different temperature transformation shapes through the shape memory alloy, and is generally used for the thermal switch of a high-temperature area. When the temperature reaches a certain value, the shape memory alloy deforms, so that the switch is switched from an on state to an off state.
The gas gap type thermal switch is divided into an open circulation type thermal switch and a closed type thermal switch, the open circulation type thermal switch can vacuumize the interior of the thermal switch and deflate the interior of the thermal switch through a vacuum pump set to complete the switching-off and the switching-on of the switch, and the closed type switch generally adsorbs heat-conducting medium gas in a closed cavity when an adsorption device reaches a certain temperature, so that the heat-conducting state of the thermal switch is changed into the switching-off state, and the switching temperature of a heat pipe is constant.
Disclosure of Invention
An object of the present invention is to provide a two-chamber heat conduction switch for a very low temperature device and a new technical solution of the very low temperature device.
According to a first aspect of the present invention there is provided a two-chamber heat conductive switch for a very low temperature device, comprising: the device comprises an upper fixing plate, a lower fixing plate, an outer cavity wall, an inner cavity wall and an adsorption pump device;
the outer cavity wall is arranged between the upper fixing plate and the lower fixing plate, and a closed cavity, namely an outer cavity, is formed by the upper fixing plate, the lower fixing plate and the outer cavity; an external cavity heat conduction device is arranged in the external cavity and forms an external switch;
the inner cavity wall is arranged between the upper fixing plate and the lower fixing plate, a closed cavity, namely an inner cavity, is formed by the upper fixing plate, the lower fixing plate and the inner cavity wall, and the inner cavity wall is arranged inside the outer cavity wall; an internal cavity heat conduction device is arranged in the internal cavity and forms an internal switch; the sorption pump means is in communication with the interior chamber;
the inner chamber and the outer chamber are filled with heat-conducting gas; the adsorption pump device is internally provided with an adsorption material;
when the extremely low temperature equipment is at room temperature, the heat conducting gas is gaseous, and at the moment, the inner switch and the outer switch are both in an on state, namely a heat conducting state;
when the temperature of the extremely low temperature equipment is gradually reduced, the temperature in the external cavity reaches a first preset value, the heat conducting gas in the external cavity is liquefied, the air pressure in the external cavity is reduced, the heat conducting capacity is reduced, and the external switch is in a closed state at the moment, namely a non-heat conducting state; the adsorption pump device heats the adsorption material, so that the adsorption material does not adsorb heat-conducting gas in the inner cavity, and the inner switch is still in an on state, namely a heat-conducting state;
when the temperature of the extremely low temperature equipment is gradually reduced and reaches a second preset value range, the adsorption pump device stops heating, and meanwhile, the adsorption pump device adsorbs heat-conducting gas in the internal cavity, so that the internal cavity becomes vacuum, the air pressure is reduced, the heat conductivity is reduced, and the internal switch is in a closed state, namely a non-heat-conducting state; at this time, both the inner switch and the outer switch of the two-cavity heat conduction switch are in an off state.
According to the technical scheme of the first aspect of the invention, the internal chamber heat conduction device comprises an upper heat conduction blade and a lower heat conduction blade, the upper heat conduction blade is connected with the upper fixing plate, the lower heat conduction blade is connected with the lower fixing plate, and a gap of 50-1000um is arranged between the upper heat conduction blade and the lower heat conduction blade.
According to the technical scheme of the first aspect of the invention, the external chamber heat conduction device comprises an external chamber upper heat conduction wall and an external chamber lower heat conduction wall, the external chamber upper heat conduction wall is connected with the upper fixing plate, the external chamber lower heat conduction wall is connected with the lower fixing plate, and a gap of 50-1000um is formed between the external chamber upper heat conduction wall and the external chamber lower heat conduction wall.
According to the technical scheme of the first aspect of the invention, the lower heat-conducting wall of the external chamber and the upper heat-conducting wall of the external chamber are both of circular tube structures, and the diameter of the lower heat-conducting wall of the external chamber is larger than that of the upper heat-conducting wall of the external chamber.
According to the technical scheme of the first aspect of the invention, the adsorption pump device of the two-cavity type heat conduction switch comprises an adsorption material, an adsorption pump, a heating copper block, a thermometer, a heating wire and a signal connector, wherein one end of the adsorption pump penetrates through the outer cavity wall and the inner cavity wall to be communicated with the inner cavity;
when the temperature of the extremely low temperature equipment reaches the temperature of the heat conduction gas in the external cavity for liquefaction, the heating wire is controlled to heat through the signal connector, the temperature of the heating copper block is controlled to be within a third preset value range, the adsorbing material is enabled to be in a state of not adsorbing the heat conduction gas, and the heat conduction gas in the internal cavity can exchange heat;
when the temperature of the extremely low temperature equipment reaches the range of a fourth preset value, the signal connector controls the heating wire to stop, the adsorption pump adsorbs heat-conducting gas in the internal cavity through an adsorption material, so that the internal switch is in an off state, namely a non-heat-conducting state, and at the moment, the whole two-cavity heat-conducting switch thermal switch is in the off state.
According to the technical scheme of the first aspect of the invention, the two-cavity heat conduction switch for the cryogenic equipment further comprises an inner cavity valve, and the inner cavity valve passes through the outer cavity wall and the inner cavity wall to be communicated with the inner cavity.
According to the technical scheme of the first aspect of the invention, the two-cavity heat conduction switch for the extremely-low temperature equipment further comprises an internal cavity valve, and the internal cavity valve passes through the upper fixing plate or the lower fixing plate and is communicated with the internal cavity.
According to the technical scheme of the first aspect of the invention, the two-cavity heat conduction switch for the cryogenic device further comprises an external cavity valve, and the external cavity valve passes through the wall of the external cavity or the upper fixing plate or the lower fixing plate to be communicated with the external cavity.
According to the technical scheme of the first aspect of the invention, the heat conducting gas inside the outer chamber is nitrogen; the heat conducting gas filled in the inner chamber is inert gas.
According to the technical scheme of the first aspect of the invention, the inner chamber and the outer chamber are filled with heat-conducting gas.
According to a second aspect of the present invention there is provided a very low temperature apparatus in which is provided a two-chamber heat-conductive switch for a very low temperature apparatus according to the first aspect of the present invention.
According to the embodiment disclosed by the invention, the following beneficial effects are achieved:
through combining active thermal switch and passive form thermal switch, combine two different temperature interval's thermal switch, can reach the thermal conductance effect that differs in high temperature district and low temperature district, obtain higher thermal conductance efficiency in the high temperature district, be favorable to the low temperature system to lower the temperature more fast in the high temperature district.
Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.
Fig. 1 is a schematic diagram of a two-chamber heat-conducting switch for a very low temperature device according to an embodiment;
fig. 2 is a diagram illustrating a two-chamber heat conduction switch for a very low temperature device according to an embodiment.
The figures are labeled as follows:
1-upper fixing plate, 2-upper fixing threaded hole, 3-outer cavity wall, 4-adsorbing material, 5-adsorbing pump, 6-heating copper block, 7-thermometer, 8-heating wire, 9-signal connector, 10-outer cavity, 11-inner cavity, 12-lower fixing plate, 13-outer cavity lower heat conducting wall, 14-lower heat conducting blade, 15-outer cavity valve, 16-outer cavity upper heat conducting wall, 17-inner cavity valve, 18-upper heat conducting blade, 19-inner cavity wall, and 20-lower fixing threaded hole.
Detailed Description
Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.
The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.
The existing gas gap type thermal switch of the active control switch has the problems of large volume and easy damage. Since the open circulation type gas gap switch requires a pump set at room temperature, the internal gas during the evacuation and the gas discharge needs to enter a gas circulation system. For closed thermal switches, there are passive control switches and active control switches.
The passive control air gap type thermal switch is mainly characterized in that working gas is filled into the air gap type thermal switch, the gas is used as a transmission medium, the gas is gaseous when the temperature is high, the thermal switch is in an 'on' state, and when the temperature is reduced to a certain value, the gas is liquefied, the thermal conductivity is reduced, and the thermal switch enters an 'off' state. Therefore, the switch temperature of the passive control switch is constant, and the active control requirement cannot be met, but the passive control switch has the advantages of simple structure, convenience in installation and suitability for commercialized and miniaturized equipment. The use requirement of the existing extremely low temperature equipment is gradually increased, and the requirement of active control on a thermal switch is required.
The active control air gap type closed thermal switch mainly uses an adsorption pump which takes active carbon and the like as raw materials as a gas adsorption device, and when the required switch state is 'on', the adsorption pump is heated to release gas adsorbed by the adsorption pump, so that the gas enters the thermal switch to conduct heat. Since the heated sorption pump is a relatively large heat source, the sorption pump is generally placed in a higher temperature region, or is supported and suspended in a vacuum environment by using a gas guide tube communicated with the thermal switch cavity, or is directly placed at room temperature outside the vacuum equipment, which causes the volume of the equipment to increase. Meanwhile, as the equipment is arranged in a vacuum cavity of the extremely-low-temperature equipment, the complex and long air pipe connecting structure can increase the air leakage risk of the vacuum system, and even can cause the gas loss of a heat transfer medium to influence the stability of the system.
In order to meet the requirements of miniaturization, convenience and stability of an active control air gap type closed thermal switch, the invention realizes a delicate air gap type thermal switch combining an extremely-low temperature active control type and a passive control type through a skillful design structure.
The first embodiment is as follows:
the present embodiment provides a two-chamber heat conduction switch (hereinafter, referred to as a thermal switch) for cryogenic equipment, wherein in the field of cryogenic equipment, cryogenic temperature refers to equipment capable of providing a temperature range of at most 1K or less, as shown in fig. 1, the two-chamber heat conduction switch includes: an upper fixing plate 1, a lower fixing plate 12, an outer cavity wall 3 and an inner cavity wall 19;
the outer cavity wall 3 is arranged between the upper fixing plate 1 and the lower fixing plate 12, and a closed cavity, namely an outer cavity 10, is formed by the upper fixing plate 1 and the lower fixing plate 12; an external cavity heat conduction device is arranged in the external cavity 10, and the external cavity heat conduction device form an external switch;
the inner cavity wall 19 is arranged between the upper fixing plate 1 and the lower fixing plate 12, a closed cavity, namely an inner cavity 11 is formed by the upper fixing plate 1 and the lower fixing plate 12, and the inner cavity wall 19 is arranged inside the outer cavity wall 3; an internal cavity heat conduction device is arranged in the internal cavity 11, and the internal cavity heat conduction device form an internal switch; the inner chamber and the outer chamber are filled with heat-conducting gas; and an adsorption material is filled in the adsorption pump device.
In some embodiments, the inner chamber wall 19 and the outer chamber wall 3 are cylindrical stainless steel tubes and are welded to the upper and lower fixation plates 1 and 3.
The inside cavity heat-transfer device includes upper portion heat conduction blade 18 and lower part heat conduction blade 14, upper portion heat conduction blade 18 with upper portion fixed plate 1 is connected, lower part heat conduction blade 14 with lower part fixed plate 12 is connected, upper portion heat conduction blade 18 with be equipped with 50-1000 um's clearance between the lower part heat conduction blade 14, the two contactless, wherein, more preferred be 50-200um, this clearance structure is compacter, and the effect is better, and the clearance is too little, and the processing degree of difficulty is big, and is with high costs to be difficult to install, the clearance is too big, and the heat conductivity is poor, and the structure is not compact, bulky.
According to the above scheme, further, the upper fixing plate 1, the lower fixing plate 12 and the internal chamber heat conducting device are made of copper materials, the three types of heat conducting devices can be connected in a welding mode, the air tightness is good, specifically, the upper heat conducting blades 18 and the lower heat conducting blades 14 are made of copper materials, in fig. 1, the internal chamber heat conducting device is a triangular wedge-shaped scheme, or can be a parallel blade scheme or an annular tube scheme like the outer chamber wall 3, the core point is that the heat transfer surfaces of the upper heat conducting blades and the lower heat conducting blades are not in contact, but the gaps are small enough, the larger the relative area is, the better the free gas space of the whole chamber is, and the smaller the free gas space of the whole chamber is.
Specifically, the internal cavity heat conduction device comprises an external cavity upper heat conduction wall 16 and an external cavity lower heat conduction wall 13, the external cavity upper heat conduction wall 16 is connected with the upper fixing plate 1, the external cavity lower heat conduction wall 13 is connected with the lower fixing plate 12, a gap of 50-1000um is arranged between the external cavity upper heat conduction wall 16 and the external cavity lower heat conduction wall 13, wherein the gap is more preferably 50-200um, the gap structure is more compact, the effect is better, the gap is too small, the processing difficulty is large, the cost is high, the installation is not easy, the gap is too large, the heat conductivity is poor, the structure is not compact, and the size is huge.
In some embodiments, the outer chamber lower heat-conducting wall 13 and the outer chamber upper heat-conducting wall 16 are both circular tube structures, and may be stainless steel tubes, and are connected to the middle of the upper fixing plate 1 and the lower fixing plate 12 by welding, so that the heat conductivity is good, and the air tightness of the cavity is ensured, and the outer chamber lower heat-conducting wall 13 has a larger diameter than the outer chamber upper heat-conducting wall 16, and the two are not in direct contact, and have a certain gap.
Preferably, a two-cavity formula heat-conduction switch for utmost point cryogenic equipment still includes the adsorption pump device, the adsorption pump device includes adsorption material 4, adsorption pump shell 5, heating copper billet 6, thermometer 7, heater strip 8 and signal connector 9, the one end of adsorption pump shell 5 is passed outer chamber wall 3 and inner chamber wall 19 and inside cavity 11 intercommunication, be provided with adsorption material 4 and heating copper billet 6 in the adsorption pump 5, be equipped with heater strip 8 and thermometer 7 in the heating copper billet 6, heater strip and thermometer are connected with signal connector 9, make things convenient for signal connection.
In some embodiments, as depicted in fig. 1, the two-chamber heat conduction switch for very low temperature devices further comprises an internal chamber valve 17, the internal chamber valve 17 communicating with the internal chamber 11 through the outer chamber wall 3 and the inner chamber wall 19.
Of course, in other embodiments, the internal chamber valve 17 has other arrangements, as shown in fig. 2, the two-chamber heat conduction switch for very low temperature equipment further includes the internal chamber valve 17, and the internal chamber valve 17 is communicated with the internal chamber 11 through the upper fixing plate 1 or the lower fixing plate 12.
In some embodiments, the inner chamber 11 is evacuated, leak picked up, and helium filled through the inner chamber valve 17.
The two-cavity heat conduction switch for the extremely-low-temperature equipment further comprises an external cavity valve 15, wherein the external cavity valve 15 penetrates through the outer cavity wall 3 or the upper fixing plate 1 or the lower fixing plate 12 to be communicated with the external cavity 10, and the external cavity is vacuumized, leaked and inflated.
In some embodiments, the inside of the outer chamber 10 and the inside of the inner chamber 11 are filled with a heat conducting gas, preferably, the outer chamber 10 is filled with nitrogen, and the inside of the inner chamber 11 is filled with an inert gas, specifically, argon, helium, neon, wherein helium is the most preferable choice.
Upper portion fixed plate 1 with lower part fixed plate 12 has last fixed screw hole 2 and fixed screw hole 20 down respectively for fix the thermal switch on two upper and lower cold drawing of utmost point cryogenic equipment, make the upper and lower fixed plate of thermal switch and two cold drawing about the equipment have fine thermal contact, when the thermal switch is the state of opening, can transmit upper portion with faster speed with the heat of equipment substructure like this, in order to reach the effect that improves the cooling rate.
According to the above scheme, further, be provided with fixed screw hole 2 on upper portion fixed plate 12, be provided with down fixed screw hole 20 on lower portion fixed plate 12 for fix the thermal switch on two upper and lower cold drawing of utmost point cryogenic equipment, make upper portion fixed plate 12, lower part fixed plate 12 and two upper and lower cold drawing of equipment of thermal switch have fine thermal contact, when the thermal switch is the state of opening, can transmit the heat of equipment substructure upper portion with faster speed like this, in order to reach the effect that improves the cooling rate.
When the extremely low temperature equipment is at room temperature, the heat conducting gas is gaseous, and at the moment, the inner switch and the outer switch are both in an on state, namely a heat conducting state;
when the temperature of the extremely low temperature equipment is gradually reduced, the temperature in the external cavity reaches a first preset value, the heat conducting gas in the external cavity is liquefied, the air pressure in the external cavity is reduced, the heat conducting capacity is reduced, and the external switch is in a closed state at the moment, namely a non-heat conducting state; the adsorption pump device heats the adsorption material, so that the adsorption material does not adsorb heat-conducting gas in the inner cavity, and the inner switch is still in an on state, namely a heat-conducting state;
when the temperature of the extremely low temperature equipment is gradually reduced and reaches a second preset value range, the adsorption pump device stops heating, and meanwhile, the adsorption pump device adsorbs heat-conducting gas in the internal cavity, so that the internal cavity becomes vacuum, the air pressure is reduced, the heat conductivity is reduced, and the internal switch is in a closed state, namely a non-heat-conducting state; at the moment, the two-cavity heat conduction switch completes heat conduction, and an inner switch and an outer switch of the two-cavity heat conduction switch are both in an off state.
According to the scheme in the previous step, further, when the temperature of the extremely low temperature equipment reaches the temperature of the heat conduction gas in the external chamber for liquefaction, the heating wire is controlled to heat through the signal connector, the temperature of the heating copper block is controlled to be within a third preset value range, the adsorbing material is enabled to be in a state of not adsorbing the heat conduction gas, and the heat conduction gas in the internal chamber can be subjected to heat exchange;
when the temperature of the extremely low temperature equipment reaches the range of a fourth preset value, the signal connector controls the heating wire to stop, the adsorption pump adsorbs heat-conducting gas in the internal cavity through an adsorption material, so that the internal switch is in an off state, namely a non-heat-conducting state, and at the moment, the whole two-cavity heat-conducting switch thermal switch is in the off state.
Wherein, two cavity formula heat conduction switch "on" state and "off" state specifically mean: the "on" state is a state with good heat conduction, and the "off" state is a state with poor heat conduction; the two-cavity heat conduction switch is essentially a heat conduction switch, namely a switch for controlling heat conduction.
According to the two-chamber type heat conduction switch for the very low temperature device, in some embodiments, the working principle and working process of the more specific application are as follows:
1. the process of the entire system cooling at utmost point cryogenic equipment begins, the system of whole utmost point cryogenic equipment is the room temperature, the state of the inner switch of hot switch and outer switch all is opened at this time and all is in the state of heat conduction promptly, the heat-conducting gas that sets up in the outside cavity is nitrogen gas, the heat-conducting gas that sets up in the inside cavity is the helium, the entire system operation of utmost point cryogenic equipment, begin the cooling, the cold head of utmost point cryogenic equipment takes away the heat on system upper portion earlier, the temperature reduces, because there is temperature gradient's existence, the heat of utmost point cryogenic equipment lower part can be conducted upper portion through hot switch.
2. The first preset temperature is when the temperature of the copper plate of the upper fixing plate 1 reaches the temperature of liquid nitrogen, generally the first preset temperature is the liquefaction temperature of the heat conducting gas in the external chamber, the nitrogen in the external chamber 10 is liquefied and settled at the upper part, the temperature of the lower part in the external chamber 10 is still above the temperature of the liquid nitrogen, when the liquid nitrogen is settled to the lower part, the heat is absorbed and evaporated, and the heat is carried to the copper plate of the upper fixing plate 1 in a reciprocating mode, so that the heat of the copper plate of the lower fixing plate 12 is carried to the copper plate of the upper fixing plate 1, and good heat transfer is formed. Until the temperature of the copper plate of the lower fixing plate 12 reaches below the liquid nitrogen temperature, the liquid nitrogen vapor pressure in the outer chamber 10 is reduced thereafter, the thermal conductivity is reduced, the partial pressure of the gas in the chamber after liquefaction becomes small, the gas between the upper and lower heat-conducting plates becomes small, the gas molecules become small, the thermal conductivity becomes poor, and at this time, the outer switch of the thermal switch is in an off state.
3. At this time, the thermal switch of the internal chamber 11 is still in an on state, but because the temperature of the whole system of the cryogenic device reaches the liquid nitrogen temperature, the heating wire is controlled to start heating through the signal connector, the temperature of the heating copper block is controlled to be about 70K, that is, the third preset value range can be 60-80K, it is ensured that the activated carbon adsorbent is not in an adsorption state, the internal chamber 11 has enough helium as heat exchange gas, at this time, the heat of the lower fixing plate 12 and the lower system is transferred to the lower heat conducting blade 14 through contact heat transfer, the heat of the lower heat conducting blade 14 is transferred to the helium in the internal chamber 11, the helium transfers the heat to the upper heat conducting blade 18, and the heat is transferred to the cold head through contact heat transfer to take out of the whole system of the cryogenic device.
4. When the temperature of the lower part of the whole system of the very low temperature equipment reaches the design temperature, for example: the cryogenic equipment is a cryogenic dilution refrigerator, the lower temperature of the cryogenic equipment reaches a temperature area of 5-10K, namely the range of a fourth preset value is 5-10K, the heating wire can be closed to stop heating, so that the temperature of the adsorption pump is gradually reduced, the adsorption material can generally make active carbon, the active carbon can gradually adsorb helium in the internal cavity 11 when the temperature of the adsorption pump is reduced, so that the state of the thermal switch of the internal cavity 11 is changed into 'off', the state of the whole thermal switch is changed into 'off', the adsorption pump adsorbs heat-conducting gas in the internal cavity through the adsorption material and enables the internal cavity to be vacuum, so that the internal switch is changed into the off state, namely the non-heat-conducting state, and at the moment, the whole two-cavity type heat-conducting switch thermal switch is changed into the off state. The next operating mode and state may be entered for very low temperature devices.
According to the design of the two-cavity type heat conduction switch for the extremely low temperature equipment, the active heat switch and the passive heat switch are combined, and the heat switches in two different temperature ranges are combined, so that different heat conduction effects in a high temperature area and a low temperature area can be achieved, higher heat conduction efficiency in the high temperature area is obtained, and the low temperature system can be cooled more quickly in the high temperature area.
The invention creatively provides a mode that the vacuum adsorption pump is tightly attached to the thermal switch, but not a mode that the vacuum adsorption pump is connected through a relatively easily damaged air pipe, so that the vacuum adsorption pump is not easily collided and damaged, and the stability of the system can be improved. When satisfying above advantage, because passive form thermoswitch is outside at active thermoswitch, when the temperature is less than liquid nitrogen temperature, when passive form thermoswitch is in the off-state, outside cavity is equivalent to a vacuum insulation layer, can reduce the direct contact heat transfer between active carbon adsorption pump and the inside cavity refrigeration cavity. Meanwhile, a thinner stainless steel material is used as the inner cavity cylinder structure and the outer cavity cylinder structure, so that the heat in the activated carbon adsorption pump is transmitted to the copper plate as little as possible in a heating state, meanwhile, the heat leakage between the upper fixing plate 1 and the lower fixing plate 12 in a thermal switch closing state is reduced, and the on-off ratio of the thermal switch is improved.
Example two:
the present embodiment provides a very low temperature device in which the two-chamber type heat conduction switch for a very low temperature device according to any one of embodiments 1 is provided.
In summary, the present invention provides a two-chamber heat conduction switch for very low temperature equipment, which combines an active thermal switch and a passive thermal switch to achieve the effect of two-stage cooling. The thermal switch is mainly characterized in that the thermal switch mainly has a double-layer cavity structure, and two different working media are respectively used in the two cavities: such as helium and nitrogen, so that the thermal switch can have two switching points. In the process of cooling the extremely low temperature equipment, in order to enable the high thermal conductivity in a high temperature area, the nitrogen in the cavity at the outer side is in a gaseous state, the thermal switch is in an open state, after the liquefaction temperature of the nitrogen is reached, the nitrogen in the cavity of the thermal switch at the outer layer is liquefied, the thermal switch is disconnected, the vacuum state is kept in the cavity, a vacuum layer is formed, and the vacuum layer can reduce the heat transfer of the active carbon adsorption pump to the cavity of the thermal switch at the inner part. The internal thermal switch is an active thermal switch and is connected to an external activated carbon adsorption pump through a thin tube and an outer vacuum layer. The activated carbon adsorption pump is provided with a heating wire and a thermometer, helium in the activated carbon is released by heating the heating wire, and the helium is not adsorbed by heating, so that the purpose of controlling the on-off of the inner side thermal switch is achieved.
Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.
Claims (10)
1. A two-chamber, heat-conductive switch for cryogenic equipment, comprising: the device comprises an upper fixing plate, a lower fixing plate, an outer cavity wall, an inner cavity wall and an adsorption pump device;
the outer cavity wall is arranged between the upper fixing plate and the lower fixing plate, and a closed cavity, namely an outer cavity, is formed by the upper fixing plate, the lower fixing plate and the outer cavity; an external cavity heat conduction device is arranged in the external cavity and forms an external switch;
the inner cavity wall is arranged between the upper fixing plate and the lower fixing plate, a closed cavity, namely an inner cavity, is formed by the upper fixing plate, the lower fixing plate and the inner cavity wall, and the inner cavity wall is arranged inside the outer cavity wall; an internal cavity heat conduction device is arranged in the internal cavity and forms an internal switch; the sorption pump means is in communication with the interior chamber;
the inner chamber and the outer chamber are filled with heat-conducting gas; the adsorption pump device is internally provided with an adsorption material;
when the extremely low temperature equipment is at room temperature, the heat conducting gas is gaseous, and at the moment, the inner switch and the outer switch are both in an on state, namely a heat conducting state;
when the temperature of the extremely low temperature equipment is gradually reduced, the temperature in the external cavity reaches a first preset value, the heat conducting gas in the external cavity is liquefied, the air pressure in the external cavity is reduced, the heat conducting capacity is reduced, and the external switch is in a closed state at the moment, namely a non-heat conducting state; the adsorption pump device heats the adsorption material, so that the adsorption material does not adsorb heat-conducting gas in the inner cavity, and the inner switch is still in an on state, namely a heat-conducting state;
when the temperature of the extremely low temperature equipment is gradually reduced and reaches a second preset value range, the adsorption pump device stops heating, and meanwhile, the adsorption pump device adsorbs heat-conducting gas in the internal cavity, so that the internal cavity becomes vacuum, the air pressure is reduced, the heat conductivity is reduced, and the internal switch is in a closed state, namely a non-heat-conducting state; at this time, both the inner switch and the outer switch of the two-cavity heat conduction switch are in an off state.
2. The two-chamber heat conduction switch for very low temperature equipment according to claim 1, wherein the inner chamber heat conduction device comprises an upper heat conduction blade and a lower heat conduction blade, the upper heat conduction blade is connected with the upper fixing plate, the lower heat conduction blade is connected with the lower fixing plate, and a gap of 50-1000um is provided between the upper heat conduction blade and the lower heat conduction blade.
3. The two-chamber heat conductive switch for very low temperature equipment according to claim 2, wherein the outer chamber heat conductive means comprises an outer chamber upper heat conductive wall and an outer chamber lower heat conductive wall, the outer chamber upper heat conductive wall is connected to the upper fixing plate, the outer chamber lower heat conductive wall is connected to the lower fixing plate, and a gap of 50-1000um is provided between the outer chamber upper heat conductive wall and the outer chamber lower heat conductive wall.
4. The two-chamber heat conductive switch for very low temperature equipment according to claim 3, wherein the outer chamber lower heat conductive wall and the outer chamber upper heat conductive wall are both of a circular tube structure, and the outer chamber lower heat conductive wall has a larger diameter than the outer chamber upper heat conductive wall.
5. The two-chamber type heat conduction switch for very low temperature equipment according to claim 3, wherein the adsorption pump device comprises an adsorption pump, a heating copper block, a thermometer, a heating wire and a signal connector, one end of the adsorption pump passes through the outer chamber wall and the inner chamber wall to be communicated with the inner chamber, the heating copper block is arranged in the adsorption pump, the heating wire and the thermometer are arranged in the heating copper block, and the heating wire and the thermometer are connected with the signal connector;
when the temperature of the extremely low temperature equipment reaches the temperature of the heat conduction gas in the external cavity for liquefaction, the heating wire is controlled to heat through the signal connector, the temperature of the heating copper block is controlled to be within a third preset value range, the adsorbing material is enabled to be in a state of not adsorbing the heat conduction gas, and the heat conduction gas in the internal cavity can exchange heat;
when the temperature of the extremely low temperature equipment reaches the range of a fourth preset value, the signal connector controls the heating wire to stop, the adsorption pump adsorbs heat-conducting gas in the internal cavity through an adsorption material, so that the internal switch is in an off state, namely a non-heat-conducting state, and at the moment, the whole two-cavity heat-conducting switch thermal switch is in the off state.
6. The two-chamber heat transfer switch for very low temperature devices of claim 1 further comprising an internal chamber valve communicating with the internal chamber through the outer chamber wall and the inner chamber wall.
7. The two-chamber heat transfer switch for a very low temperature device of claim 1, further comprising an inner chamber valve communicating with the inner chamber through the upper fixing plate or the lower fixing plate.
8. The two-chamber heat transfer switch for a very low temperature device of claim 1, further comprising an external chamber valve communicating with an external chamber through the outer chamber wall or the upper or lower fixed plate.
9. The two-chamber heat transfer switch for very low temperature equipment of claim 1, wherein the heat transfer gas inside the outer chamber is nitrogen; the heat conducting gas filled in the inner chamber is inert gas.
10. A very low temperature device, characterized in that a two-chamber type heat conduction switch for a very low temperature device according to any one of claims 1 to 9 is provided in the very low temperature device.
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| CN114396825B (en) | 2023-08-15 |
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