CN106092329B - Integrated micro Dewar inner tube and implementation method - Google Patents
Integrated micro Dewar inner tube and implementation method Download PDFInfo
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- CN106092329B CN106092329B CN201610538849.3A CN201610538849A CN106092329B CN 106092329 B CN106092329 B CN 106092329B CN 201610538849 A CN201610538849 A CN 201610538849A CN 106092329 B CN106092329 B CN 106092329B
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- 238000000034 method Methods 0.000 title claims abstract description 10
- 238000003466 welding Methods 0.000 claims abstract description 21
- 238000005219 brazing Methods 0.000 claims abstract description 11
- 229910000679 solder Inorganic materials 0.000 claims description 50
- 238000001514 detection method Methods 0.000 claims description 36
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 24
- 238000007789 sealing Methods 0.000 claims description 21
- 239000007789 gas Substances 0.000 claims description 20
- 238000010168 coupling process Methods 0.000 claims description 18
- 238000005859 coupling reaction Methods 0.000 claims description 18
- 230000008878 coupling Effects 0.000 claims description 17
- 239000000463 material Substances 0.000 claims description 17
- 239000007788 liquid Substances 0.000 claims description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims description 12
- 239000001307 helium Substances 0.000 claims description 10
- 229910052734 helium Inorganic materials 0.000 claims description 10
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 10
- 239000010935 stainless steel Substances 0.000 claims description 10
- 229910001220 stainless steel Inorganic materials 0.000 claims description 10
- 238000003754 machining Methods 0.000 claims description 6
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 claims description 4
- NEIHULKJZQTQKJ-UHFFFAOYSA-N [Cu].[Ag] Chemical group [Cu].[Ag] NEIHULKJZQTQKJ-UHFFFAOYSA-N 0.000 claims description 4
- 238000002844 melting Methods 0.000 claims description 4
- 230000008018 melting Effects 0.000 claims description 4
- 239000010936 titanium Substances 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- 238000010622 cold drawing Methods 0.000 claims description 3
- 238000007654 immersion Methods 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- 229910001069 Ti alloy Inorganic materials 0.000 claims description 2
- 238000001816 cooling Methods 0.000 claims description 2
- 238000000227 grinding Methods 0.000 claims description 2
- 238000007514 turning Methods 0.000 claims description 2
- 239000010964 304L stainless steel Substances 0.000 claims 1
- 238000005057 refrigeration Methods 0.000 abstract description 8
- 238000010923 batch production Methods 0.000 abstract description 3
- 230000009467 reduction Effects 0.000 abstract description 2
- 230000009286 beneficial effect Effects 0.000 abstract 1
- 238000002360 preparation method Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 238000007664 blowing Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J5/02—Constructional details
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- Spectroscopy & Molecular Physics (AREA)
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Abstract
The invention discloses an integrated miniature Dewar inner tube and an implementation method thereof. One end of the cold finger is arranged on the cold finger base and is welded into a whole by adopting a brazing mode, the other end of the cold finger is arranged on the cold head, and the cold head and the cold finger are brazed into a whole. The invention not only meets the rigidity required by the support of the detector, but also realizes the air tightness required by low-temperature refrigeration when the high-pressure working medium expands and the high precision required by the reciprocating motion of the movable part of the refrigerator. The invention reduces the heat load of the integrated micro Dewar inner tube, and is composed of three parts of airtight welding, thereby being beneficial to batch production and cost reduction. The invention has simple structure, convenient operation and good compatibility and can be applied to various integrated infrared detector components.
Description
Technical Field
The invention relates to a low-temperature miniature Dewar assembly technology, in particular to an integrated miniature Dewar inner tube and an implementation method, which are suitable for integrated packaging of a refrigeration type infrared detector.
Background
The infrared detector Dewar component has wide application in the aerospace infrared field. With the wavelength expansion to long wave and the improvement of detection sensitivity, the infrared detector must work at a deep low temperature. Because the mechanical refrigeration has the advantages of compact structure, small volume, light weight, short refrigeration time, large adjustable range of refrigeration temperature and the like, the detection device of the type at present mostly adopts a mechanical refrigeration mode in application. The Stirling refrigerator is one of the mechanical refrigeration methods which are frequently selected. Compared with the Stirling refrigerator with a free piston structure, the Stirling refrigerator with the rotating motor and the crank connecting rod structure has the advantages of compact structure, high efficiency, mature technology and low price, and is widely applied.
Because the cold quantity provided by the Stirling refrigerating machine with the rotating motor and the crank connecting rod structure is generally small, when the refrigeration type infrared detector is packaged, the infrared detector is mostly directly installed on an inner pipe of a miniature Dewar, the Dewar inner pipe is connected with the Stirling refrigerating machine in a matching mode, and the refrigerating quantity provided by the refrigerating machine directly cools the Dewar inner pipe. The Dewar inner tube is a carrier supported by the low-temperature detector and is also an expansion cavity of high-pressure working medium of the refrigerator. The control and stiffness of the dewar inner tube thermal load is a key to design and fabrication. In foreign countries, the micro Dewar inner tube is mainly prepared by thales company in France and Ricor company in Israel, but the preparation method is not reported. In China, a Chinese patent 'miniature metal inner tube for guidance' (201310000806.6) mainly reports the structure of a Dewar inner tube, and from the patent drawings, the Dewar inner tube is formed by welding a cold platform after being machined traditionally, and the preparation method is not reported. In order to reduce the heat load of the dewar inner tube and to reduce the cost of mass production, a new method must be explored to solve the problem.
Disclosure of Invention
The invention aims to provide an integrated miniature Dewar inner tube and an implementation method thereof, which can reduce the heat load of the integrated miniature Dewar inner tube and meet the requirements of batch production and cost reduction.
The purpose of the invention is realized by the following steps: the integrated micro Dewar inner tube is composed of a cold finger base 1, a cold finger 2 and a cold head 3, as shown in figure 1.
The shape of the cold finger base 1 is like a hollow boss, and the material is stainless steel 304L. The cold finger base 1 is internally provided with a circular solder slot hole 101, a cold finger guide hole 102, a cold finger positioning hole 103 and a coupling sealing hole 104. The diameter of the solder slot hole 101 is 0.6mm-1mm larger than the diameter of the outer circle of the cold finger 2, and the depth is 0.5mm-1 mm. The diameter of the cold finger guide hole 102 is 0.005mm-0.01mm larger than the diameter of the excircle of the cold finger 2, and the depth is 1mm-3 mm. The diameter of the cold finger positioning hole 103 is 1mm-1.3mm smaller than the diameter of the inner circle of the cold finger 2, and the depth is 0.5mm-1.5 mm. The diameter of the coupling sealing hole 104 is 11.9mm-12.1mm, and the depth is 12mm-13 mm. The outer side of the cylindrical surface of the cold finger base 1 is provided with a circular convex edge 105, the lower end surface of the circular convex edge 105 is provided with a circular groove 106, the groove depth is 0.5mm-0.6mm, and the groove width is 0.9mm-1.1 mm.
The shape of the cold finger 2 is like a hollow cylinder, and the material is stainless steel 304L, titanium alloy TC4 or GH 605. The diameter of the inner circle of the cold finger 2 is 7.5mm-7.7mm, the diameter of the outer circle of the cold finger 2 is respectively processed into a linear type, an inverted cone type or a stepped type with a thickened lower end according to requirements, the wall thickness of the part processed close to the end of the cold head 3 is 0.1mm-0.3mm, and the total height of the cold finger 2 is 46mm-47 mm.
The material of the cold head 3 is 4J32 or 4J 29. The lower end of the cylindrical surface is provided with a circular boss-shaped gas expansion platform 301, the outer diameter of the gas expansion platform 301 is 0.005mm-0.015mm larger than the inner circle diameter of the cold finger 2, and the height is 1mm-2 mm. An annular convex edge solder loading platform 302 is arranged on the outer side of the gas expansion platform 301, the inner diameter of the solder loading platform 302 is 0.6mm-1mm larger than the outer diameter of the cold finger 2, and the height of the solder loading platform 302 is 0.5mm-1.5mm lower than that of the gas expansion platform 301. The outer diameter of a device mounting table 303 at the upper end of the cold head 3 is 14.9mm-15.1mm, and the thickness is 0.5mm-0.6 mm.
The lower end surface of the cold finger 2 is inserted into the cold finger guide hole 102 of the cold finger base 1 and is welded into a whole in a brazing mode, and then the upper end surface of the cold finger 2 is inserted into the solder loading platform 302 of the cold head 3, and the cold head 3 and the cold finger 1 are brazed into a whole.
The invention discloses a preparation method of an integrated micro Dewar inner tube, which comprises the following steps:
(1) when parts are machined, the diameter of the integrated miniature Dewar inner tube needs to be 0.2-0.4 mm smaller than that of a finished product. The cold finger 2 is formed by mechanical processing or cold drawing, and honing processing is carried out after forming to ensure that the cylindricity of the cold finger is less than 0.03 mm; the thickness of the device mounting table 303 at the upper end of the cold head 3 is 0.1mm-0.2mm thicker than the designed size during machining and forming; the lower end face of the cold finger 2 is inserted into the cold finger guide hole 102 of the cold finger base 1, and the welding flux slot hole 1 of the cold finger base 101 and the diameter of the outer circle of the cold finger 2, the solder is evenly and fully filled into the fit clearance, the mixture is put into a vacuum brazing furnace, the vacuum degree is lower than 1 multiplied by 10 -3 Pa. On the basis of the melting point of the solder, 10-30 ℃ is increased to be used as the welding temperature, and the welding is carried out for 5-10 min. If the material of the cold finger 2 is stainless steel or GH605, the solder is iron-nickel alloy (brand DHNi-C); if the material of the cold finger 2 is selected to be TC4, the solder is selected to be titanium-based (40Ti20Zr20Cu20 Ni).
(2) And (3) a special core rod is plugged into an inner hole of the cold finger 2, the outer circumferential surface of the cold finger 2 and the coupling sealing hole 104 of the cold finger base 1 are processed to the required size by taking the special core rod as a reference, and the coaxiality of the coupling sealing hole 104 and the inner hole of the cold finger 2 is ensured to be lower than 0.02 mm.
(3) Under the assistance of special frock, honing the interior circle of cold finger 2 for the roughness of the interior circle of cold finger 2 is less than Ra0.4, and the circularity is less than 0.02mm, and the cylindricity is less than 0.03 mm.
(4) The gas expansion platform 301 at the lower end of the cold head 3 is inserted into the upper end of the core column 2 and then is inverted, and the solder is filled into the gap between the inner side of the solder loading surface 302 of the cold head 3 and the excircle of the cold finger 2. The solder is silver-copper material (brand Ag72Cu28), and is placed into a vacuum brazing furnace with the vacuum degree lower than 1 × 10 -3 Pa, increasing 10-30 ℃ as the welding temperature on the basis of the melting point of the solder, and keeping for 5-20 minutes for welding.
(5) And (3) completely immersing the cold head 3 in liquid nitrogen, taking out after the immersion time is 1-3 minutes, keeping the room temperature for more than 5 minutes, and repeating for 5-10 times.
(6) The upper end face of the device mounting table 303 of the cold head 3 is turned, and the reserved margin is machined to the design size. And then, grinding the inner hole of the cold finger by using a special tool to ensure that the cylindricity of the inner circle of the cold finger 2 is lower than 0.02 mm.
(7) The prepared integrated micro Dewar inner tube is subjected to leak detection by a special tool, and when the leak rate is less than 3 multiplied by 10 -11 Pa.m 3 And when the leak detection is successful, the leak detection is qualified, as shown in figure 2.
(8) Helium gas of 5MPa is filled into the inner cavity of the prepared integrated micro Dewar inner tube by using special tools for leak detection, and when the leak rate is less than3×10 -11 Pa.m 3 And when the leak detection is successful, the leak detection is qualified, as shown in figure 3.
(9) And pouring a proper amount of liquid nitrogen into the inner cavity of the prepared integrated micro Dewar inner tube by using a special tool, so that the cold head of the integrated micro Dewar inner tube is cooled to the required temperature of 77K. When the liquid nitrogen surface is evaporated to the welding seam of the cold finger base 1 and the cold finger 2, helium is filled into the cold tube for leak detection, and when the leak rate is less than 3 multiplied by 10 -11 Pa.m 3 And when the leakage is detected in seconds, the leakage detection is qualified. When the liquid nitrogen is consumed quickly, helium is filled into the cold tube for leak detection, and when the leak rate is less than 3X 10 -11 Pa.m 3 At/s, the leak detection is acceptable, as shown in FIG. 4.
Thus, the preparation of the integrated micro Dewar inner tube is completed.
The invention has the advantages that:
(1) the invention has simple structure, convenient operation and low cost;
(2) the compatibility is good, and the infrared detector is applied to various integrated infrared detector components;
(3) the heat load of the Dewar inner pipe can be reduced, the batch production is facilitated, and the cost is reduced.
Drawings
Fig. 1 is a general diagram of an integrated micro dewar inner tube:
in the figure: 1-cold finger base;
101-solder slot;
102-cold finger guide holes;
103-cold finger positioning hole;
104-coupling seal holes;
105-circular convex edge;
106-circular groove;
2-cold finger;
3, cooling the head;
301-gas expansion stage;
302-solder loading station;
303 — device mounting table.
Fig. 2 is a diagram of an integrated miniature Dewar inner tube normal-temperature normal-pressure leak detection device.
Fig. 3 is a diagram of a normal-temperature high-pressure leak detection device for an integrated miniature Dewar inner tube.
Fig. 4 is a diagram of an integrated miniature Dewar inner tube low-temperature normal-pressure leak detection device.
Fig. 5 is a ladder-type cold finger diagram of an integrated micro Dewar inner tube.
Fig. 6 is an inverted cone-shaped cold finger diagram of the integrated micro dewar inner tube.
Detailed Description
The following detailed description of embodiments of the invention is provided in conjunction with the appended drawings:
example 1 is GH605 integrated micro dewar inner tube:
as shown in figure 1, the material of the cold finger base 1 is stainless steel 304L, the upper end of the cylinder of the cold finger base is provided with a circular welding flux groove hole 101, the diameter is 9 +/-0.1 mm, and the depth is 1 mm. The diameter of the cold finger pilot hole 102 is
The depth was 1.5 mm. The diameter of the cold finger locating hole 103 is
The depth is 0.5 mm. The coupling sealing hole 104 has a diameter of 12 + -0.1 mm and a depth of 12.6 mm. The circular flange 105 has an outer diameter of 31.9mm and a height of 3.6 mm. The circular groove 106 has an outer diameter of 27mm, a groove width of 1mm and a groove depth of 0.6 mm. The shape of the cold finger 2 is like a hollow cylinder, the material is GH605, and the diameter of the inner circle is
Diameter of outer circle
The length of the cold finger 2 is 46.5 mm. The cold finger 2 is formed by cold drawing, and honing processing is carried out after forming to ensure that the cylindricity of the cold finger is better than 0.03 mm. The material of the cold head 3 is 4J32, and the excircle diameter of the gas expansion platform 301 of the cold head 3 is
The depth was 1.5 mm. The outer side of the gas expansion platform 301 is provided with an annular convex-edge solder loading platform 302, the inner diameter of the solder loading platform 302 is 8.8 + -0.1 mm, the depth is 0.6mm, and the height of the solder loading platform 302 is 0.5mmmm lower than that of the gas expansion platform 301. The height of the device mounting table 303 on the upper part of the cold head 3 after machining and forming is 0.2mm higher than the forming height of the integrated micro Dewar inner tube. The procedure of example 1 is as follows:
(1) the lower end face of the cold finger 2 is inserted into a cold finger guide hole 102 of the cold finger base 1, iron-nickel alloy solder (brand DHNi-C) is added into a gap between a solder groove hole 101 of the cold finger base 1 and the cold finger 2, the iron-nickel alloy solder is uniformly and fully filled into a matching gap, and the vacuum brazing furnace is put into the gap. Vacuum degree better than 1X 10 -3 Pa, the welding temperature is 1055 ℃, and the welding is carried out after 15 min.
(2) A special core rod is plugged into an inner hole of the cold finger 2, the outer circumferential surface of the cold finger 2 and the coupling sealing hole 104 of the cold finger base 1 are processed by taking the special core rod as a reference, and the processing diameter of the coupling sealing hole 104 is
And simultaneously, the coaxiality of the coupling sealing hole 104 and the inner hole of the cold finger 2 is ensured to be better than 0.02 mm.
(3) The inner circle of the cold finger 2 is honed, so that the roughness of the inner circle of the cold finger 2 is better than Ra0.4, the circumferential degree of the inner circle is better than 0.02mm, and the cylindricity is better than 0.03 mm.
(4) And inserting the gas expansion table 301 at the lower end of the cold head 3 into the upper end of the core column 2, and then inverting, and filling the solder into a gap between the inner side of the solder loading table 302 of the cold head 3 and the excircle of the cold finger 2. The solder is silver copper solder (brand: Ag72Cu28), put into a vacuum brazing furnace, the vacuum degree is better than 1 x 10-3Pa, the welding temperature is 810 ℃, and the solder is kept for 10 minutes.
(5) And completely immersing the cold head 3 in liquid nitrogen, taking out the cold head after 3 minutes of immersion time, keeping the temperature at room temperature for 7 minutes, and repeating the steps for 8 times.
(6) And (4) performing turning on the device mounting table 303 of the cold head 3, and processing the reserved allowance to be 66.5 +/-0.02 mm. The inner bore of the cold finger 2 is ground with a special tool. The cylindricity of the inner circle of the cold finger 2 is ensured to be better than 0.02 mm.
(7) Prepared by special toolAnd carrying out normal-temperature leak detection on the integrated miniature Dewar inner tube. The principle of the special tool is shown in the attached figure 2, and the special tool comprises a leakage detection port seat, a leakage detection test tube and a fixed pressing block. The special tool and the integrated miniature Dewar inner tube are sealed through a sealing medium (an O-shaped ring), and four screws are screwed in for compressing. Inserting the integrated miniature Dewar inner tube with special tool into leak detector via leak detection test tube, starting the detector, and blowing helium gas into the inner cavity of the integrated miniature Dewar inner tube, when the leak rate is less than 3 × 10 -11 Pa.m 3 And when the leakage is detected in seconds, the leakage detection is qualified.
(8) And (3) carrying out pressurization leak detection on the prepared integrated micro Dewar inner tube by using a special clamp. The principle of the special fixture is shown in attached figure 3, and the special fixture comprises a leakage detection port seat, a leakage detection test tube, a fixing cover cap and an inflation clamping and sealing tube. The special fixture and the integrated micro Dewar inner tube are sealed through a sealing medium (O-shaped ring), four screws are screwed in for compressing, helium of 5MPa is filled into an inner cavity of the Dewar inner tube through the inflation clamp sealing tube, and the inflation clamp sealing tube is clamped and sealed. Inserting the integrated miniature Dewar inner tube with special fixture into the leak detector via the leak detection test tube, starting the detector, and when the leak rate is less than 3 × 10 -11 Pa.m 3 And when the leakage is detected in seconds, the leakage detection is qualified.
(9) And (3) carrying out low-temperature leak detection on the prepared integrated micro Dewar inner tube by using a special tool, as shown in the attached figure 4. The special tool and the integrated miniature Dewar inner tube are sealed through a sealing medium (an O-shaped ring), and four screws are screwed in for compressing. And inserting the integrated micro Dewar inner tube provided with the special tool into a leak detector through a leak detection test tube, and pouring a proper amount of liquid nitrogen into the inner cavity of the integrated micro Dewar inner tube to cool the cold head of the integrated micro Dewar inner tube to the required temperature of 77K. When the liquid nitrogen surface is evaporated to the welding seam between the cold finger base 1 and the cold finger 2, filling helium gas into the inner cavity of the integrated micro Dewar inner tube for leak detection, and when the leak rate is less than 3 × 10 -11 Pa.m 3 And when the leakage is detected in seconds, the leakage detection is qualified. When liquid nitrogen is consumed quickly, helium is used for blowing the welding part of the core column 2 and the cold head 3 for leakage detection, and when the leakage rate is less than 3 multiplied by 10 -11 Pa.m 3 And when the leakage is detected per second, the leakage detection is qualified.
The preparation of the GH605 integrated micro Dewar inner tube is completed.
Example 2 is TC4 integrated miniature dewar inner tube:
as shown in FIG. 5, the material of the cold finger base 1 is stainless steel 304L, the upper end of the cylinder is provided with a circular solder slot hole 101, the diameter is 9.8 +/-0.1 mm, and the depth is 1 mm. The diameter of the cold finger pilot hole 102 is
Depth of 1.5mm, diameter of the cold finger positioning hole 103
The depth is 0.5 mm. The coupling seal hole 104 has a diameter of 12mm and a depth of 12.6 mm. The circular flange 105 has an outer diameter of 31.9mm and a height of 3.6 mm. The circular groove 106 has an outer diameter of 27mm, a groove width of 1mm and a groove depth of 0.6 mm. The cold finger 2 is a hollow cylinder step type, the material is TC4, and the diameter of the inner circle is
The diameter of the outer circle near the cold head 3
The length is 37 +/-0.1 mm; the diameter of the excircle close to the cold finger base 1 is 8.8mm, and the length is 10 mm. The cold finger 2 is formed by machining, as shown in fig. 5. Honing is carried out after forming, so that the cylindricity of the honing tool is better than 0.03 mm. The cold head 3 corresponds to example 1. The steps of this example are as follows:
(1) the lower end face of the cold finger 2 is inserted into the cold finger guide hole 102 of the cold finger base 1, and titanium-based solder (40Ti20Zr20Cu20Ni) is added into the gap between the solder groove hole 101 of the cold finger base 1 and the cold finger 2. Filling the Ti-based solder into the gap, and brazing in a vacuum brazing furnace to obtain a vacuum degree of 1 × 10 -3 Pa, the welding temperature is 910 ℃, and the welding is carried out after 15 minutes of holding.
(2) A special core rod is plugged into an inner hole of the cold finger 2, the outer circumferential surface of the cold finger 2 and the coupling sealing hole 104 of the cold finger base 1 are processed by taking the special core rod as a reference, and the diameter of the coupling sealing hole 104 of the cold finger base 1 is equal to
mm while ensuring that the coaxiality of the coupling seal hole 104 and the inner hole of the cold finger 2 is better than 0.02 mm.
(3) The inner circle of the cold finger 2 is honed, so that the roughness of the inner circle of the cold finger 2 is better than Ra0.4, the circumference of the inner circle is better than 0.02mm, and the cylindricity is better than 0.03 mm.
(4) The steps (4) to (9) of example 1 were repeated to complete the preparation of the TC4 integrated miniature dewar inner tube.
Example 3 is a stainless steel integrated micro dewar inner tube:
as shown in fig. 6, the cold finger base 1 is the same as embodiment 2. The cold finger 2 is in an inverted cone shape and is formed by machining, and the material is stainless steel 316L. The diameter of the inner circle of the cold finger 2 is
The diameter of the outer circle near the cold head 3 is
The diameter of the outer circle close to the cold finger base 1 is 8.8mm, and the total length is 46.5 mm. The diameter of the excircle near the cold finger base 1 is
The length is 6 +/-0.1 mm, and the diameter of the rest length is changed from 8mm to 8.8 mm. After the forming, honing processing is carried out, so that the cylindricity of the honing tool is better than 0.03mm, as shown in figure 6. The cold head 3 corresponds to examples 1 and 2. The procedure of this example was the same as that of example 1, and the preparation of the stainless steel integrated micro dewar inner tube was completed by repeating the steps (1) to (9) of example 1.
Claims (2)
1. The utility model provides a miniature dewar inner tube of integrated form, includes cold finger base (1), cold finger (2), cold head (3), its characterized in that:
the cold finger base (1) is in a hollow boss shape and made of 304L stainless steel, a circular solder slotted hole (101), a cold finger guide hole (102), a cold finger positioning hole (103) and a coupling sealing hole (104) are sequentially arranged on the cold finger base (1) from the upper surface to the lower surface of the cold finger base, wherein the solder slotted hole (101) is communicated with the upper surface, the coupling sealing hole (104) is communicated with the lower surface of the cold finger base, the diameter of the solder slotted hole (101) is 0.6mm-1mm larger than the excircle diameter of the cold finger (2), and the depth of the solder slotted hole is 0.5mm-1 mm; the diameter of the cold finger guide hole (102) is 0.005mm-0.01mm larger than the diameter of the excircle of the cold finger (2), and the depth is 1mm-3 mm; the diameter of the cold finger positioning hole (103) is 1mm-1.3mm smaller than the diameter of the inner circle of the cold finger (2), and the depth is 0.5mm-1.5 mm; the diameter of the coupling sealing hole (104) is 11.6mm-11.8mm, and the depth is 12mm-13 mm; the outer side of the cylindrical surface of the cold finger base (1) is provided with a circular convex edge (105), the lower end surface of the circular convex edge (105) is provided with a circular groove (106), the groove depth is 0.5mm-0.6mm, and the groove width is 0.9mm-1.1 mm;
the material of the cold finger (2) is stainless steel 304L, titanium alloy TC4 or GH 605; the diameter of the inner circle of the cold finger (2) is 7.5mm-7.7mm, the diameter of the outer circle of the cold finger (2) is processed into a linear type, an inverted cone type or a step type with a thickened lower surface according to requirements, the wall thickness of the part close to the end of the cold head (3) after processing is 0.1mm-0.3mm, and the total height of the cold finger (2) is 46mm-47 mm;
the cold head (3) is made of 4J32 or 4J29, the lower end of the cylindrical surface of the cold head is provided with a circular boss-shaped gas expansion table (301), the outer diameter of the gas expansion table (301) is 0.005-0.015 mm larger than the inner circle diameter of the cold finger (2), and the height is 1-2 mm; an annular convex-edge solder loading platform (302) is arranged on the outer side of the gas expansion platform (301), the inner diameter of the solder loading platform (302) is 0.6-1 mm larger than the outer diameter of the cold finger (2), and the height of the solder loading platform (302) is 0.5-1.5 mm lower than that of the gas expansion platform (301); the upper end of the cold head (3) is provided with a device mounting table (303), the outer diameter of the device mounting table is 14.9-15.1 mm, and the thickness of the device mounting table is 0.5-0.6 mm;
the lower end face of the cold finger (2) is inserted into a cold finger guide hole (102) of the cold finger base (1) and is welded into a whole in a brazing mode, then the upper end face of the cold finger (2) is inserted into a solder loading platform (302) of the cold head (3), and the cold head (3) and the cold finger (2) are brazed into a whole.
2. A method of implementing the integrated micro dewar inner tube of claim 1, comprising the steps of:
1) during machining of partsThe diameter of the integrated micro Dewar inner tube is required to be smaller than the diameter of a finished product by 0.2mm-0.4 mm; the cold finger (2) is formed by mechanical processing or cold drawing, and honing processing is carried out after forming to ensure that the cylindricity of the cold finger is less than 0.03 mm; the thickness of the device mounting table (303) at the upper end of the cold head (3) is 0.1mm-0.2mm thicker than the design size during machining and forming; inserting the lower end face of the cold finger (2) into a cold finger guide hole (102) of the cold finger base (1), adding solder into a gap between a solder slotted hole (101) of the cold finger base (1) and the excircle diameter of the cold finger (2), filling the solder into the matched gap uniformly and fully, putting the gap into a vacuum brazing furnace, and keeping the vacuum degree lower than 1 x 10 -3 Pa, increasing 10-30 ℃ as a welding temperature on the basis of the melting point of the solder, and keeping for 5-10min for welding; if the material of the cold finger (2) is stainless steel or GH605, the solder is iron-nickel alloy; if the material of the cold finger (2) adopts TC4, the solder adopts titanium-based solder;
2) a special core rod is plugged into an inner hole of the cold finger (2), the outer circumferential surface of the cold finger (2) and a coupling sealing hole (104) of the cold finger base (1) are machined to required sizes by taking the special core rod as a reference, and the coaxiality of the coupling sealing hole (104) and the inner hole of the cold finger (2) is ensured to be lower than 0.02 mm;
3) under the assistance of a special tool, honing the inner circle of the cold finger (2) to ensure that the roughness of the inner circle of the cold finger (2) is lower than Ra0.4, the roundness is lower than 0.02mm, and the cylindricity is lower than 0.03 mm;
4) inserting a gas expansion table (301) at the lower end of a cold head (3) into the upper end of a cold finger (2) and then inverting the gas expansion table, filling a solder into a gap between the inner side of a solder loading table (302) of the cold head (3) and the excircle of the cold finger (2), wherein the solder is a silver-copper material, putting the silver-copper material into a vacuum brazing furnace, and keeping the vacuum degree lower than 1 x 10 -3 Pa, increasing 10-30 ℃ as a welding temperature on the basis of the melting point of the solder, and keeping for 5-20 minutes for welding;
5) completely immersing the cold head (3) in liquid nitrogen, taking out after the immersion time is 1-3 minutes, keeping the room temperature for more than 5 minutes, and repeating for 5-10 times;
6) turning the upper end face of a device mounting table (303) of the cold head (3), and processing the reserved allowance to the designed size; grinding the inner hole of the cold finger (2) by using a special tool to ensure that the cylindricity of the inner circle of the cold finger (2) is lower than 0.02 mm;
7) the prepared integrated micro Dewar inner tube is subjected to leak detection by a special tool, and when the leak rate is less than 3 multiplied by 10 -11 Pa.m 3 When the leakage is detected in seconds, the leakage is qualified;
8) helium gas of 5MPa is filled into the inner cavity of the prepared integrated micro Dewar inner tube by using special tools for leak detection, and when the leak rate is less than 3 multiplied by 10 -11 Pa.m 3 When the leakage is detected in seconds, the leakage is qualified;
9) pouring a proper amount of liquid nitrogen into the inner cavity of the prepared integrated micro Dewar inner tube by using a special tool, and cooling the cold head (3) of the integrated micro Dewar inner tube to the required temperature of 77K; when the liquid nitrogen surface is evaporated to the welding seam of the cold finger base (1) and the cold finger (2), helium is filled into the cold tube for leak detection, and when the leak rate is less than 3 multiplied by 10 -11 Pa.m 3 When the leakage is detected in seconds, the leakage is qualified; when the liquid nitrogen is consumed quickly, helium is filled into the cold tube for leak detection, and when the leak rate is less than 3X 10 -11 Pa.m 3 And when the leakage is detected in seconds, the leakage detection is qualified.
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| CN201620318436 | 2016-04-15 | ||
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| CN201610538849.3A Active CN106092329B (en) | 2016-04-15 | 2016-07-11 | Integrated micro Dewar inner tube and implementation method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107511549A (en) * | 2017-09-04 | 2017-12-26 | 中国电子科技集团公司第十研究所 | A kind of compound cold bench and its manufacture method |
| CN109655165B (en) * | 2019-01-10 | 2020-11-24 | 中国科学院上海技术物理研究所 | Integrated packaging structure for inhibiting noise influence of refrigeration working medium on infrared detector |
| CN111571498B (en) * | 2020-05-11 | 2021-11-05 | 中国电子科技集团公司第十一研究所 | Device for assembling multiband detector chip |
| CN111595463B (en) * | 2020-05-22 | 2022-11-08 | 中国科学院上海技术物理研究所 | Split type Dewar cold platform with low contact thermal resistance and coupling stress isolation |
| CN112241018A (en) * | 2020-10-09 | 2021-01-19 | 中核核电运行管理有限公司 | Gas cold finger sampling device |
| CN114406400A (en) * | 2022-02-24 | 2022-04-29 | 中国科学院上海技术物理研究所 | Titanium alloy core column and invar cold head combining piece brazing clamp and method |
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| JPH04315017A (en) * | 1990-12-21 | 1992-11-06 | Santa Barbara Res Center | Remote-ignition high-frequency getter used in dewar of metal infrared-ray detector |
| JPH08261821A (en) * | 1995-03-27 | 1996-10-11 | Mitsubishi Electric Corp | Infrared detector |
| US5598966A (en) * | 1994-07-19 | 1997-02-04 | Santa Barbara Research Center | Brazed lower vacuum housing for a dewar |
| CN103048052A (en) * | 2013-01-05 | 2013-04-17 | 昆明物理研究所 | Miniature metal Dewar inner tube for guidance |
| CN105136313A (en) * | 2015-09-22 | 2015-12-09 | 中国科学院上海技术物理研究所 | Liquid nitrogen horizontal refrigeration device for testing infrared detector Dewar assembly and design method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL231731B (en) * | 2014-03-27 | 2019-12-31 | Semi Conductor Devices An Elbit Systems Rafael Partnership | Ruggedized dewar unit for integrated dewar detector assembley |
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2016
- 2016-07-11 CN CN201620721537.1U patent/CN205898305U/en not_active Expired - Fee Related
- 2016-07-11 CN CN201610538849.3A patent/CN106092329B/en active Active
Patent Citations (5)
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|---|---|---|---|---|
| JPH04315017A (en) * | 1990-12-21 | 1992-11-06 | Santa Barbara Res Center | Remote-ignition high-frequency getter used in dewar of metal infrared-ray detector |
| US5598966A (en) * | 1994-07-19 | 1997-02-04 | Santa Barbara Research Center | Brazed lower vacuum housing for a dewar |
| JPH08261821A (en) * | 1995-03-27 | 1996-10-11 | Mitsubishi Electric Corp | Infrared detector |
| CN103048052A (en) * | 2013-01-05 | 2013-04-17 | 昆明物理研究所 | Miniature metal Dewar inner tube for guidance |
| CN105136313A (en) * | 2015-09-22 | 2015-12-09 | 中国科学院上海技术物理研究所 | Liquid nitrogen horizontal refrigeration device for testing infrared detector Dewar assembly and design method thereof |
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| CN205898305U (en) | 2017-01-18 |
| CN106092329A (en) | 2016-11-09 |
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