JP2006333970A - Method of manufacturing vacuum structure and the vacuum structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum structure capable of obtainiong a stable heat insulation performance and simultaneously performing a surface treatment. <P>SOLUTION: In the method of manufacturing a vacuum structure to obtain high vacuum from 10<SP>-4</SP>Torr to 10<SP>-6</SP>Torr by discharging air from the internal space 13 of components 11 and 12 in low vacuum from 10<SP>-2</SP>Torr to 1 Torr, sealing the internal space, post-heating and activating a getter 15; the getter 15 is composed of an alloy containing zirconium, and the getter 15 is disposed for an amount exceeding 0.33 mg/cm2 to the surface area of an inner wall surface forming the internal space 13. Also, in the state of attaching a surface material forming a surface layer 20, post-heating is performed from 250°C to 830°C, and the activation of the getter 15 and the surface treatment of the constituting members are simultaneously performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a vacuum structure such as a thermos, a vacuum double tube, a vacuum double jacket, a vacuum heat insulation panel, a vacuum vessel, and the like, and a vacuum structure therefor.

  Prior art document information relating to the method of manufacturing a vacuum structure according to the present invention includes the following.

Japanese Patent Publication No. 2-55153 JP 2003-65490 A

In Patent Document 1, a structure is placed in a vacuum heating furnace and maintained at a heating temperature of 580 to 600 ° C. and a vacuum degree of 10 ⁻⁴ to 10 ⁻⁵ Torr (10 ⁻² to 10 ⁻³ Pa) for about 1 hour. After that, a method of sealing three exhaust holes having a diameter of 0.5 mm with an electron beam welder is disclosed.

However, in order to obtain such a high vacuum degree of 10 ⁻⁴ to 10 ⁻⁵ Torr, in addition to a roughing rotary pump, expensive equipment such as an oil diffusion pump that requires attention to maintenance is required. Moreover, since it takes a long time to vacuum, there is a disadvantage that the processing time required for this equipment is long, resulting in high processing costs.

Therefore, the present applicant provides a method for manufacturing a vacuum heat insulator described in Patent Document 2. In this manufacturing method, the internal space of the structure is evacuated and sealed at a low vacuum of 0.75 × 10 ⁻² Torr (1 Pa) to about 0.75 Torr (1 × 10 ² Pa), and then heated. By activating the getter, a high vacuum degree of 10 ⁻⁴ Torr to 10 ⁻⁶ Torr is obtained.

  According to the manufacturing method described in Patent Document 2, the problem described in Patent Document 1 can be sufficiently solved. However, in order to obtain a stable degree of vacuum (heat insulation performance) by this method, it is necessary to select the state before exhaust, which contributes to the gas contained in the constituent members of the vacuum structure and the gas attached to the surface, and the material and amount of the getter. It becomes a decisive factor. In addition, when using this type of vacuum structure, it is preferable to perform surface treatment in order to provide functionality with corrosion resistance or decoration with appearance, but this surface treatment processing is expensive. There is a drawback that is necessary.

  The present invention has been made in view of conventional problems, and can be manufactured in a short time with a simple exhaust facility, and at the same time, a surface treatment process can be performed, and a stable heat insulation performance can be secured at a low cost. It is an object of the present invention to provide a manufacturing method and a vacuum structure thereof.

In order to solve the above-mentioned problems, a method for manufacturing a vacuum structure according to the present invention includes a getter disposed on the internal space side of a component member, and the internal space is exhausted at a low vacuum of 10 ⁻² Torr to 1 Torr. After sealing, in the method of manufacturing a vacuum structure in which the getter is post-heated and activated to obtain a high vacuum of 10 ⁻⁴ Torr to 10 ⁻⁶ Torr, the getter is made of an alloy containing zirconium, The getter is configured to be disposed in an amount exceeding 0.33 mg / cm ² with respect to the surface area of the inner wall surface forming the internal space.

  According to the present invention, since the exhaust is performed in a low vacuum, the exhaust speed of the gas molecules is high, and the temperature rise speed of the structural members of the structure is also high. As a result, degassing from the constituent members and exhausting of the closed internal space are promoted, and as a result, exhaust time is shortened. Specifically, the exhaust of the internal space is not a high vacuum pump such as an oil diffusion pump, but a vacuum roughing pump conventionally used as an auxiliary pump, specifically, a rotary pump only, or A rotary pump and a mechanical booster pump can be used in combination. Therefore, exhaust can be started up instantly.

In addition, since the getter is made of an alloy containing zirconium and is disposed in an amount exceeding 0.33 mg / cm ² with respect to the surface area of the inner wall surface of the constituent member, stable heat insulation performance can be obtained with certainty.

  In this manufacturing method, the post-heating is performed at 250 ° C. to 830 ° C. in a state where a surface material for forming a surface layer is adhered to at least a part of the surface of the component member, and activation of the getter and component member are performed. It is preferable to perform the surface treatment simultaneously. In this way, the process related to the manufacture of the vacuum structure can be simplified, and the manufacturing cost can be greatly reduced.

  In this case, it is preferable that the post-heating is performed in a state where a heat-resistant cover is disposed on the sealing portion of the constituent member. If it does in this way, the conditions regarding the sealing method of an exhaust part can be eased.

Further, the vacuum structure of this manufacturing method, after sealing was evacuated with low vacuum of 1Torr from 10 ^-2 Torr to interior components, 10 by activating the getter by post-heating ^-4 In a vacuum structure having a high vacuum level of 10 ⁻⁶ Torr from Torr, the getter is made of an alloy containing zirconium, and the getter is 0.33 mg / cm ² with respect to the surface area of the inner wall surface forming the internal space. It is arranged in an amount exceeding.

In the method for manufacturing a vacuum structure and the vacuum structure according to the present invention, since the exhaust is performed at a low vacuum, the exhaust speed of gas molecules is high, and the temperature rise speed of the structural members of the structure is also high. As a result, the degassing from the constituent members and the exhaustion of the closed internal space are promoted, so that the exhaust time is shortened. In addition, the getter activated by post-heating after sealing is made of an alloy containing zirconium, and is disposed in an amount exceeding 0.33 mg / cm ² with respect to the surface area of the inner wall surface of the constituent member. It is possible to reliably obtain the heat insulation performance. In addition, since the post-heating is performed at 250 ° C. to 830 ° C. in a state where the surface material for forming the surface layer is adhered, the getter activation and the surface treatment of the constituent members are performed simultaneously. The manufacturing process can be simplified. As a result, the manufacturing cost can be greatly reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and FIGS. 2A and 2B show a thermos bottle 10A which is a vacuum structure according to the first embodiment of the present invention. FIGS. 3A, 3B to 6 show the manufacturing method thereof. Show. The thermos 10A includes a metal inner bottle 11 and an outer bottle 12 made of stainless steel (SUS304) or the like. The inner bottle 11 and the outer bottle 12 are respectively composed of body bodies 11a and 12a and bottom plates 11b and 12b. The trunks 11a and 12a are joined to each other by welding or the like, and an internal space 13 having a high vacuum degree of 10 ⁻⁴ Torr to 10 ⁻⁶ Torr is formed between them.

  A metal foil 14 made of copper or aluminum for preventing radiant heat transfer is wound around the outer surface of the body 11a of the inner bottle 11.

  A getter 15 for adsorbing the gas generated in the internal space 13 is disposed on the bottom plate 12b of the outer bottle 12 so as to be located on the internal space 13 side. Moreover, the recessed part 16 recessed outward (downward in FIG. 1) is provided in the center. In the center of the recess 16, an exhaust portion 17 that is further recessed outward is provided, and an exhaust port 18 for exhausting the internal space 13 is provided at the tip of the exhaust portion 17. The exhaust port 18 is closed by welding a separate sealing plate 19.

The getter 15 is for maintaining a desired degree of vacuum by absorbing gas generated in the internal space 13, and is made of an alloy containing zirconium, preferably an alloy containing zirconium as a main component (70% by weight). Is good. The getter 15 according to the present embodiment has a block shape, and exceeds 0.33 mg / cm ² with respect to the inner wall surface forming the internal space 13, specifically, the surface area of the outer surface of the inner bottle 11 and the inner surface of the outer bottle 12. It is equivalent to. The getter 15 may be made of a thin foil.

  In the present embodiment, the surface of the thermos 10A, that is, the inner surface of the inner bottle 11 and the outer surface of the outer bottle 12 is provided with a function to prevent corrosion resistance, such as baking by baking or fluorine coating. A layer 20 is provided.

  Next, a method for manufacturing the thermos bottle 10A will be described.

  First, as shown in FIG. 2A, a metal foil 14 is wound around an inner bottle 11 in which a bottom plate 11b is joined to a body 11a. Further, as shown in FIG. 2B, a getter 15 is disposed on the bottom plate 12 b of the outer bottle 12. And as shown to FIG. 3 (A), the inner bottle 11 is inserted from the lower end opening of the body 12a of the outer bottle 12, and a mutual opening part is joined. Thereafter, as shown in FIG. 3B, a bottom plate 12b is disposed on the body 12a of the outer bottle 12 and joined to each other. Thereby, the double container 10B before exhaust is formed. The assembly process of the double container 10B can be variously modified.

  Next, as shown in FIG. 4, the exhaust pipe 22 is pressed through the seal member 21 to the exhaust port 18 of the double container 10 </ b> B, and the rotary pump 24 is connected to the exhaust pipe 22 through the pipe 23. In addition, a leak test device 25 is connected to the pipe 23. If the rotary pump 24 is used in combination with a mechanical booster pump (not shown) instead of using the rotary pump 24 alone, the exhaust can be instantly started.

Subsequently, the rotary pump 24 is driven to evacuate the internal space 13 of the double container 10B to a low vacuum level of 10 ⁻² Torr to 1 Torr. In addition, although this exhaust process can be performed at normal temperature, you may perform in the state heated at the temperature of about 250 degrees C or less as needed.

  Next, in a state where this low vacuum is maintained, the leak test device 25 inspects whether there is a leak in the internal space 13 of the double container 10B, and when it is confirmed that there is no leak, FIG. As shown, the sealing plate 19 is welded and joined to the exhaust part 17 of the double container 10B. As a result, a thermos bottle 10C in a low vacuum exhaust state is formed.

  Many thermos bottles 10C are manufactured by the above method, and these are processed collectively in the following steps. First, as shown in FIG. 5B, a surface material for forming the surface layer 20 is attached to the inner surface of the inner bottle 11 and the outer surface of the outer bottle 12 of the thermos bottle 10C by coating or spraying.

Subsequently, a large number of thermos bottles 10C are accommodated in a heating furnace (not shown) and heated from 250 ° C to 830 ° C. Thereby, the getter 15 inside the thermos bottle 10C is sufficiently activated by the heat transmitted from the outer bottle 12, and the occluded gas on the metal surfaces of the inner bottle 11 and the outer bottle 12 is sufficiently released. As a result, the occluded gas released into the inner space 13 of the thermos bottle 10C is absorbed by the getter 15 together with the residual air. As a result, the internal space 13 reaches a high vacuum level of 10 ⁻⁴ Torr to 10 ⁻⁶ Torr.

  Further, the surface material attached to the thermos bottle 10 </ b> C is baked or baked by the post-heating, and the surface layer 20 is formed simultaneously with the activation of the getter 15. Thereby, the thermos 10A in which the desired surface layer 20 is formed with a high degree of vacuum shown in FIG. 1 is obtained.

Here, when the temperature of the post-heating is lower than 250 ° C., the formation time of the surface layer 20 by the activation of the getter 15 and the fluorine processing or coating processing becomes very long. Is not realistic. Moreover, when the post-heating temperature is higher than 830 ° C., there is a problem that high-temperature oxidation occurs when the metal material is exposed to a high temperature in the atmosphere. Incidentally, in SUS304, it is said that high-temperature oxidation occurs at 870 ° C. to 925 ° C. or more, but since oxidation occurs gradually even at a temperature below that, treatment at the lowest possible temperature is desirable. Further, the metal foil 14 disposed in the internal space 13 needs to be treated at a saturation vapor pressure or lower in order to prevent a decrease in performance. When an aluminum foil or a copper foil is used, the saturation is 10 ⁻⁶ Torr. It is desirable that the vapor pressure is 1000 ° C or lower. Moreover, among the surface treatments performed simultaneously, the baking temperature of enamel is 600 to 830 ° C. Therefore, in the present invention, the heating temperature is set to 250 ° C. to 830 ° C. including the various surface treatment temperatures so that the getter 15 can be reliably activated.

FIG. 6 shows changes in pressure and temperature in the internal space 13 in the method for manufacturing a vacuum structure described above. When the internal space 13 of the double container 10B is exhausted, the pressure in the internal space 13 decreases from 1 atmosphere to 10 ⁻² Torr. Here, after performing a leak test at the point T, the exhaust part 17 is sealed with the sealing plate 19 at the point S. At this time, even after the internal space 13 of the double container 10B is sealed, the occluded gas continues to be released from the surfaces of the metallic inner bottle 11 and the outer bottle 12 which are constituent members. It will increase.

Next, when the thermos 10C is heated to 450 ° C. in a heating furnace, the occluded gas is sufficiently released and released from the surfaces of the inner bottle 11 and the outer bottle 12, so that the pressure in the inner space 13 further increases. When the getter 15 is activated by heating, the liberated stored gas is absorbed by the getter 15 together with residual air. As a result, the pressure in the inner space 13 of the thermos bottle 10C gradually decreases and reaches a desired high vacuum level of about 2.25 × 10 ⁻⁵ Torr. At the same time, the surface layer 20 is formed.

As described above, in the manufacturing method according to the first embodiment, since the exhaust is performed at a low vacuum, the exhaust speed of the gas molecules is high, and the temperature rise speed of the constituent members of the structure is also high. Therefore, degassing from the inner bottle 11 and the outer bottle 12 which are constituent members and the exhaust of the closed internal space 13 are promoted, and the exhaust time is shortened. Moreover, since the getter 15 is made of an alloy containing zirconium and is disposed in an amount exceeding 0.33 mg / cm ² with respect to the surface area of the inner wall surface of the constituent member, stable heat insulation performance can be reliably obtained. .

  In the above embodiment, the leak test and the sealing are performed by performing the leak test of the internal space 13 before sealing the internal space 13 and performing the seal when it is confirmed that there is no leak. The process is performed. In addition, post-heating is performed in a state where the surface material forming the surface layer 20 is adhered, and the activation of the getter 15 and the surface treatment of the thermos bottle 10C are performed simultaneously. Therefore, the manufacturing process can be greatly simplified, and the manufacturing cost can be greatly reduced.

  FIG. 7 shows a thermos bottle 10A according to the second embodiment, and FIGS. 8A and 8B and FIGS. 9A and 9B show a manufacturing method thereof. This thermos bottle 10 is different from the first embodiment in that the tip tube 26 is disposed in the exhaust part 17 with a brazing material and the exhaust part 17 is covered with a heat-resistant cover 27. The cover 27 includes a cap 28 made of a metal material such as aluminum in consideration of the bonding strength with the bottom plate 12 b of the outer bottle 12, and a filler 29 made of ceramic filled in the cap 28.

  Next, a method for manufacturing the thermos bottle 10A of the second embodiment will be described.

  First, as in the first embodiment, from the lower end opening of the body 12a of the outer bottle 12, the bottom plate 11b is joined to the body 11a, the inner bottle 11 around which the metal foil 14 is wound is inserted, and the mouths of each other are joined. . Thereafter, the getter 15 is disposed on the body 12a of the outer bottle 12 and the bottom plate 12b on which the tip tube 26 is disposed is bonded to each other. Thereby, as shown to FIG. 8 (A), the double container 10B before exhaust_gas | exhaustion is formed.

Next, the exhaust pipe 22 is pressed against the exhaust port 18 of the double container 10B and the rotary pump 24 is driven to exhaust the internal space 13 of the double container 10B to a low vacuum level of 10 ⁻² Torr to 1 Torr. Next, when the leak test apparatus 25 confirms that there is no leak while maintaining this low vacuum degree, the tip tube 26 of the double container 10B is sealed as shown in FIG. 8B. As a result, a thermos bottle 10C in a low vacuum exhaust state is formed.

  Subsequently, as shown in FIG. 9A, the cap 28 filled with the filler 29 is joined to the thermos bottle 10C. Then, as shown in FIG. 9B, a surface material for forming the surface layer 20 is attached to the inner surface of the inner bottle 11 and the outer surface of the outer bottle 12 of the thermos bottle 10C.

After that, as in the first embodiment, a large number of thermos bottles 10C are accommodated in a heating furnace (not shown) and heated, the getter 15 is activated, and the internal space 13 is brought to a high vacuum level of 10 ⁻⁴ Torr to 10 ⁻⁶ Torr. At the same time, the desired surface layer 20 is formed.

  The thermos 10A having the above-described configuration can eliminate the possibility that the brazing material is melted during post-heating and the tip tube 26 is detached by the cover 27. As a result, it is possible to obtain a thermos bottle 10A having a high vacuum level similar to that in the first embodiment, and the same actions and effects can be obtained. In addition, since the cover 27 is not affected by heat at the time of post-heating, the method for sealing the exhaust part 17 is not limited, and the sealing conditions can be relaxed.

In the manufacturing method in which the thermos 10C evacuated at a low degree of vacuum is made into a thermos 10A having a high degree of vacuum by post-heating, in order to obtain a stable degree of vacuum (= insulation performance), the inner bottle 11 and the outer parts which are constituent members are used. The pretreatment of the bottle 12 and the selection of the material and amount of the getter 15 activated by post-heating are decisive factors. The present inventors have found through a diligent experiment that the getter 15 made of an alloy containing zirconium is disposed in an amount exceeding 0.33 mg / cm ² with respect to the surface area of the inner wall surface forming the internal space 13. It is a thing.

  In this experiment, stainless steel outer bottle 12 and inner bottle 11 which are constituent members of a vacuum structure were prepared as pre-treatment before exhaustion, both with and without baking at temperatures up to 450 ° C. did. The post-heating temperature was 520 ° C. to 550 ° C., and the post-heating time was changed between 45 minutes and 60 minutes. Furthermore, the experiment was performed under various conditions for the amount of the getter 15. As a result, it has been found that by arranging a certain amount of getter 15 in the internal space 13 that is evacuated, stable quality can be obtained without being affected by the presence or absence of pretreatment.

That is, since the amount of gas adhering to the inner wall is larger than the amount of gas in the internal space 13 among the residual gas in the internal space 13 after the low vacuum exhaust, the getter 15 per unit area of the internal space 13 The weight of is a measure. When this value is 0.17 mg / cm ² , the variation of the heat retention effect is large, and the range is estimated to be within the range of 36.0 ° C to 55.8 ° C with a 95% confidence limit. There are some that can ensure heat retention performance at a sufficiently high vacuum of 52.0 ° C or higher, but they are not stable.

Therefore, when the amount of the getter 15 is increased to 0.33 mg / cm ² , the variation is reduced to a range of 51.3 ° C. to 56.8 ° C. Furthermore, when the amount of the getter 15 is increased to 0.50 mg / cm ^2, the dispersion of the pretreatment (history) before exhausting the structure is absorbed and stable heat retention performance is obtained. That is, stable quality can be obtained by providing the getter 15 in an amount exceeding 0.33 mg / cm ² .

From the above results, in the present invention, the getter 15 made of an alloy containing zirconium is disposed in an amount exceeding 0.33 mg / cm ² with respect to the surface area of the inner wall surface forming the internal space 13, so that after-heating Thus, it is possible to reliably obtain a vacuum structure having stable heat insulation performance. Moreover, since the activation of the getter 15 and the surface treatment can be performed simultaneously by post-heating, the manufacturing cost can be greatly reduced.

  In addition, the manufacturing method of the vacuum structure of this invention and its vacuum structure are not limited to the structure of the said embodiment, A various change is possible.

  In particular, the vacuum structure that can be manufactured by the above-described manufacturing method is not limited to the thermos 10A, but can be applied to a vacuum double tube, a vacuum double jacket, a vacuum heat insulation panel, a vacuum vessel, and the like, and obtains the same operation and effect. be able to.

It is a fragmentary sectional view which shows the thermos which is the vacuum structure of 1st Embodiment which concerns on this invention. (A) is a fragmentary sectional view which shows an inner bottle, (B) is a fragmentary sectional view which shows an outer bottle. (A) is the 1st process of a manufacturing method, (B) is a fragmentary sectional view showing the 2nd process of a manufacturing method. It is a fragmentary sectional view showing the 3rd process of a manufacturing method. (A) is a 4th process of a manufacturing method, (B) is a fragmentary sectional view which shows the 5th process of a manufacturing method. It is a figure which shows the change of the pressure and temperature of an internal space at the time of manufacture. It is a fragmentary sectional view which shows the thermos which is the vacuum structure of 2nd Embodiment. (A) is the 1st process of a manufacturing method, (B) is a fragmentary sectional view showing the 2nd process of a manufacturing method. (A) is a 3rd process of a manufacturing method, (B) is a fragmentary sectional view which shows the 4th process of a manufacturing method. It is a figure which shows the result of having experimented the relationship between the quantity of a getter, and heat retention effect.

Explanation of symbols

10A ... High vacuum thermos 10B ... Double container 10C ... Low vacuum thermos 11 ... Inner bottle (component)
12 ... Outer bottle (component)
DESCRIPTION OF SYMBOLS 13 ... Internal space 14 ... Metal foil 15 ... Getter 18 ... Exhaust port 19 ... Sealing plate 20 ... Surface layer 27 ... Cover 28 ... Cap 29 ... Filler

Claims (4)

A getter is disposed on the internal space side of the constituent member, the internal space is evacuated and sealed at a low vacuum of 10 ⁻² Torr to 1 Torr, and then the getter is activated by post-heating. ^In a manufacturing method of a vacuum structure that obtains a high vacuum degree of ^-4 Torr to 10 ^-6 Torr,
The getter is made of an alloy containing zirconium, and the getter is disposed in an amount exceeding 0.33 mg / cm ² with respect to the surface area of the inner wall surface forming the internal space. .   The post-heating is performed at 250 ° C. to 830 ° C. in a state where a surface material for forming a surface layer is adhered to at least a part of the surface of the component member, and activation of the getter and surface treatment of the component member are performed. The vacuum structure manufacturing method according to claim 1, wherein the vacuum structure is performed simultaneously.   The method of manufacturing a vacuum structure according to claim 2, wherein the post-heating is performed in a state where a heat-resistant cover is disposed on a sealing portion of the constituent member. The internal space of the component member is evacuated and sealed at a low vacuum of 10 ⁻² Torr to 1 Torr, and then heated to activate the getter to increase the vacuum of 10 ⁻⁴ Torr to 10 ⁻⁶ Torr. In the vacuum structure
The getter is made of an alloy containing zirconium, and the getter is disposed in an amount exceeding 0.33 mg / cm ² with respect to the surface area of the inner wall surface forming the internal space.

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