CN1206686C - Thermal switch for controlling cooling of infrared detector - Google Patents
Thermal switch for controlling cooling of infrared detector Download PDFInfo
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- CN1206686C CN1206686C CN 02150896 CN02150896A CN1206686C CN 1206686 C CN1206686 C CN 1206686C CN 02150896 CN02150896 CN 02150896 CN 02150896 A CN02150896 A CN 02150896A CN 1206686 C CN1206686 C CN 1206686C
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- thermal switch
- spring
- memory alloy
- heat conducting
- cold
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Abstract
The present invention discloses a thermal switch for controlling the cooling of an infrared detector. The present invention comprises a memory alloy spring, an ordinary small spring, a drum-shaped heat conducting copper sheet, a cold junction and a heat conducting block, wherein the memory alloy spring performs the functions of sensing temperature and generating shrinkage force; the ordinary small spring assists the movement of the memory alloy spring, provides drawing force and provides the optimal contact force of the heat conducting block and a cooling platform; the drum-shaped heat conducting copper sheet mainly performs the function of heat conduction and simultaneously moves with the movement of the spring; the cold junction is convenient for connecting a cold source; the heat conducting block is used for the good thermocontact with the cooling platform. The present invention has the advantages of large movement range which can reach 1mm, effective disconnection thermal resistance increase, cold loss reduction, exquisite thermal switch appearance, simple structure and easy realization.
Description
Technical field
The present invention relates to remember thermal switch, specifically be meant a kind of thermal switch that is used to control space Infrared Detectors cooling usefulness.
Background technology
Along with space to ground is observed to polynary, focal plane technology and the development of long wave detection direction, detector requires more and more higher to space refrigeration, require more low temperature on the one hand, as about 60K, require bigger cold on the other hand, as 1～2W, also more and more higher to life requirements simultaneously, as 3～5 years.Finish this task, the space radiation Refrigeration Technique is unable to do what one wishes, and the mechanically refrigerated life-span has restricted its further application.For improving mechanical refrigeration useful life spatially, people utilize many refrigeration machines that same chill station output cold is realized requirement.It utilizes existing sterlin refrigerator, under nominal situation, uses one of them refrigeration machine as main frame, and other refrigeration machine is as backup machine.When main frame breaks down, use backup machine to freeze, improve the reliability and the life-span of whole refrigerating system with this.For avoiding backup machine and chill station hot link to consume the cold of chill station, a thermal switch is set between each refrigeration machine and chill station, allows thermal switch be in " opening " and " pass " two states respectively to realize refrigeration machine and be connected and to disconnect with chill station.Like this, when main refrigeration machine normally provided cold, we allowed the thermal switch conducting, cold is passed to chill station by thermal switch, and for the refrigeration machine that backs up, allows thermal switch be in off-state, cold just can not leak the refrigeration machine that is in normal temperature to this like this, has improved the efficient of whole refrigerating system.When main refrigeration machine breaks down, at this moment will utilize the refrigeration machine of backup to substitute main refrigeration machine cold will be provided, and open and back up the thermal switch that refrigeration machine links to each other, and allow cold flow to chill station, disconnect the thermal switch of the main refrigeration machine of existing fault simultaneously, reduce the loss of cold.If the refrigeration machine of many backups is arranged, such substituting just can be carried out repeatedly, to reach the useful life of whole refrigerating system.Another use of thermal switch is exactly to open the time of a plurality of refrigeration machines with the minimizing chill station simultaneously, and can satisfy the refrigeration requirement of big cold.
The existing thermal switch that is used for the space in home and abroad mainly contains following two types at present:
1. contact thermal switch
A. early stage contact thermal switch: in the airship of seven Surveyor series that the U.S. launched between in January, 968 in May, 1966 to one, the refrigeration of controlling infrared platform adopts shuttle contact thermal switch, it utilizes the heat sensitivity of thermometal bar to make the contact plug generation move up and down, when contact plug contacts with the radiation lid, heat passage is opened, otherwise closes.The contact thermal switch of this form has a shortcoming, and that is exactly that structure is comparatively complicated, and contact heat resistance is bigger.
B. in order to simplify the structure of above-mentioned contact thermal switch, and improve its service behaviour, the Si Weier spacelab has proposed a kind of new thermal switch.The thermal switch structure of this novelty is very simple, mainly contains three parts and forms: thin-wall stainless steel steel pipe, two small one and large one columniform beryllium rounding dishes.Its operation principle is to utilize two kinds of different materials: the expansion shrinkage of stainless steel and beryllium is different, thereby realizes the switch motion of thermal switch, as shown in Figure 1.The shortcoming of the thermal switch of this form is: because the difference of stainless steel and beryllium expansion shrinkage is limited, therefore the gap that produces is very little, has only 0.05-0.13mm, makes that like this disconnection thermal resistance of device is less, and cold damage is serious.Next is that the beryllium metal has radioactivity, and processing is difficulty comparatively.
C. the USA space Dynamic Test Chamber has been produced a kind of model machine of thermal switch, and the operation principle of this thermal switch equally also is to utilize the difference of different metal thermal effect to make.Its shortcoming also is that cold damage is serious because the too small disconnection thermal resistance that causes in gap is too small.
2 GAP TYPE thermal switch
NASA has developed a thermal switch that is used for the 2K temperature, and it mainly is to utilize in the inflation between two conducting strips and bleed to make thermal conductivity between the two poles of the earth of whole thermal switch that the variation of several magnitude be arranged, and realizes the function of thermal switch " opening " and " pass ".Weak point is the air gap that it will process a 0.01mm, and technological requirement is high; Owing to the existence of gas, it is higher to the seal request of device simultaneously; The GAP TYPE thermal switch mainly is applicable to utmost point low temperature environment, and the temperature as 0.1K in the magnetic refrigeration is not suitable for this warm area of 50-100K.
Summary of the invention
The objective of the invention is to develop a kind of can be under steric requirements, 50～100K warm area uses, and is simple in structure, the thermal switch that the thermal resistance that is easy to process is bigger.
The object of the present invention is achieved like this, and thermal switch comprises: memory alloy spring, common little spring, cydariform heat conduction copper sheet, cold head and heat-conducting block.Memory alloy spring is enclosed within outside the little spring, two of little spring are enclosed within respectively on the step of two boss, and circle has a radial direction through hole at the bottom of the boss, and two Dan Huang Silk of memory alloy spring penetrate the radial direction through hole of two boss respectively, and affixed with through hole, constitute an elastomer that is subjected to temperature sense.This elastomer embeds in the cydariform heat conduction copper sheet, and two ends are connected with heat-conducting block with cold head by screw respectively about it, constitute a thermal switch thus.
Memory alloy spring plays temperature sensor, produces the effect of convergent force; The effect of common little spring has two, and one. the motion of assisted memory alloy spring provides tensile force; Two. the best contact force of heat-conducting block and infrared platform is provided; Cydariform heat conduction copper sheet mainly plays conductive force, also can move along with movement of springs simultaneously; Cold head be for the ease of with being connected of low-temperature receiver; Heat-conducting block be for the good thermo-contact of chill station.
The thermal switch course of work of the present invention is as follows:
Free state: the i.e. machining state of cydariform copper sheet.
The launch environment state: owing to be in the restoring force effect that the extended state memory alloy spring provides, little spring is in compressive state, and this moment, thermal switch was in off-state.
Low-temperature working state: when ambient temperature reaches the 220K left and right sides, memory alloy spring begins to soften, its power can't overcome the elastic force of little spring, little spring drives heat-conducting block and moves upward, when temperature reached the 150K left and right sides, heat-conducting block contacted fully with chill station, and its contact force is provided by the little spring that still is in compressive state, this moment, thermal switch was in closure state, and cold passes to chill station by thermal switch by low-temperature receiver.When refrigeration machine quits work, working temperature goes back up to about 150K, and memory alloy spring produces restoring force, and when temperature is higher than 220K, thermal switch is in off-state again, and the cold transmission stops, and thermal switch is got back to the normal temperature state again.
The present invention has following effect:
1. because the present invention adopts the memory alloy material of high reliability, therefore, switch varies with temperature and is quick on the draw.
2. movement travel is big, can reach 1mm, has effectively increased the disconnection thermal resistance and (has disconnected thermal resistance＞1000K/W), thereby reduced cold damage (the heat conduction temperature difference＜4K/W).
3. elegant in shape, simple in structure, be easy to realize.
Description of drawings
Fig. 1 is a cross-sectional view of the present invention;
Fig. 2 is a boss cross-sectional view of the present invention;
Fig. 3 is three kinds of state diagrams of cydariform heat conduction copper sheet of the present invention.
Embodiment
See Fig. 1, memory alloy spring 3 is enclosed within outside the little spring 4, two of little spring are enclosed within respectively on the step 201 of two boss 2, circle has a radial direction through hole 202 at the bottom of the boss, two springs of memory alloy spring penetrate the radial direction through hole 202 of two boss respectively, and affixed with through hole, constitute an elastomer that is subjected to temperature sense.This elastomer embeds in the cydariform heat conduction copper sheet 5, and two ends are connected with heat-conducting block 1 with cold head 7 by screw 6 respectively about it, constitute a thermal switch thus.
We have used the spring of two kinds of materials among the present invention.Little spring adopts common carbon element alloy steel material; Memory alloy spring is a memory alloy material, and this kind material has the memorial alloy effect.So-called shape memory effect is owing to martensitic phase transformation causes.When temperature is reduced to a certain temperature M
s, beginning martensitic phase transformation in alloy parent phase (often being austenite), M
sBe called martensite start temperature; Along with the further reduction of temperature, martensite volume increases gradually, up to M
fTemperature, martensitic phase transformation stops, M
fBe called the martensitic phase transformation final temperature.When memorial alloy is begun to heat up by low temperature, arrive A
sTemperature, martensite begin to change A to parent phase
sBe called the martensite reverse transformation and begin temperature; Temperature continues to raise, and martensite volume reduces gradually, when temperature arrives A
fThe time, martensite finishes A to the transformation of parent phase
fThe final temperature that is called the reverse change of martensite.M
s, M
f, A
s, A
fApplication to memorial alloy is very important.According to the actual conditions that thermal switch is used, the marmem martensite that is used for thermal switch changes final temperature A to parent phase
fRequirement is equal to or less than launch environment temperature, M
fMemorial alloy serviceability temperature when being higher than the mechanical refrigerator operate as normal.Have only the said temperature of satisfying condition, memorial alloy is in parent phase under the launch environment temperature, and after the mechanical refrigerator start, the beginning martensitic phase transformation changes, and when the mechanical refrigerator operate as normal, memorial alloy is in safe martensitic state.The present invention selects for use the NiTi memorial alloy as preferred material, the stable performance of NiTi marmem, and reversible strain is big, and cycle-index is less to the influence of memory performance decline, and practical application is very favourable.The phase transition temperature of memory alloy material is among the present invention: A
s＞150K, A
f＜220K, M
s＜220K, M
f＞150K.
Cydariform copper sheet design among the present invention should be taken into account mechanics and calorifics requirement, and by finite element analysis, it is comparatively suitable to draw drum organization, is convenient to switch motion and heat conduction like this, sees Fig. 3.Among Fig. 3 501 is free state: i.e. the machining state of cydariform copper sheet, and it highly is 15mm; Launch environment state 502: highly be 13mm; Low-temperature condition 503: highly be 14mm.Consider the calorifics requirement, the part material among the present invention all adopts red copper except that memory alloy spring and little spring.
Claims (2)
1. one kind is used to control the thermal switch that Infrared Detectors cools off usefulness, and comprising: memory alloy spring (3), little spring (4), cydariform heat conduction copper sheet (5), cold head (7) and heat-conducting block (1) is characterized in that:
Memory alloy spring (3) is enclosed within outside the little spring (4), two of little spring are enclosed within respectively on the step (201) of two boss (2), circle has a radial direction through hole (202) at the bottom of the boss, two springs of memory alloy spring penetrate the radial direction through hole (202) of two boss respectively, and it is affixed with through hole, constitute an elastomer that is subjected to temperature sense, this elastomer embeds in the cydariform heat conduction copper sheet (5), and two ends are connected with heat-conducting block (1) with cold head (7) by two screws (6) respectively about it.
2. according to a kind of thermal switch that is used to control Infrared Detectors cooling usefulness of claim 1, it is characterized in that: said memory alloy spring (3) is made for memorial alloy NiTi material; Little spring (4) is made for the carbon element alloy steel material, and remaining parts is the red copper material and makes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02150896 CN1206686C (en) | 2002-11-28 | 2002-11-28 | Thermal switch for controlling cooling of infrared detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02150896 CN1206686C (en) | 2002-11-28 | 2002-11-28 | Thermal switch for controlling cooling of infrared detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1412802A CN1412802A (en) | 2003-04-23 |
| CN1206686C true CN1206686C (en) | 2005-06-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 02150896 Expired - Fee Related CN1206686C (en) | 2002-11-28 | 2002-11-28 | Thermal switch for controlling cooling of infrared detector |
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| CN (1) | CN1206686C (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100499004C (en) * | 2007-10-31 | 2009-06-10 | 中国科学院上海技术物理研究所 | Bi-directional shift cool switch for spacing mechanical refrigeration system |
| CN104654692A (en) * | 2013-11-22 | 2015-05-27 | 中国科学院理化技术研究所 | Air gap type thermal switch applied to extremely-low-temperature refrigerator and heat conduction method thereof |
| CN104217894B (en) * | 2014-09-19 | 2016-07-06 | 中国科学院电工研究所 | A kind of conduction cooling superconducting magnet cryogenic heat switch |
| CN105304409A (en) * | 2015-09-11 | 2016-02-03 | 中国科学院理化技术研究所 | Thermal switch based on negative thermal expansion |
| CN107424853B (en) * | 2017-04-24 | 2019-01-22 | 上海交通大学 | A kind of electromagnetic clutch active control contact apparatus for heating switch for cryogenic system |
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2002
- 2002-11-28 CN CN 02150896 patent/CN1206686C/en not_active Expired - Fee Related
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|---|---|
| CN1412802A (en) | 2003-04-23 |
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Granted publication date: 20050615 Termination date: 20161128 |