JP2004065393A

JP2004065393A - Method for producing metallic vacuum structure

Info

Publication number: JP2004065393A
Application number: JP2002226399A
Authority: JP
Inventors: Tatsujiro Hyodo; 兵頭　龍二郎; Hiroshi Haida; 拝田　寛; Arata Suzuki; 鈴木　新
Original assignee: Zojirushi Corp
Current assignee: Zojirushi Corp
Priority date: 2002-08-02
Filing date: 2002-08-02
Publication date: 2004-03-04
Anticipated expiration: 2022-08-02
Also published as: JP3682276B2

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an oxide film from being formed on the surface of components in the production of a metallic vacuum structure. <P>SOLUTION: The metallic structural members 4 and 5 are arranged in a heating furnace 2. Air in the furnace 2 is purged with inert gas. The inert gas heated by a gas burner 19 is supplied into the furnace 2 to keep positive pressure, and closed space 6 is heated and simultaneously exhausted via an exhaustion hole 7. The hole 7 is sealed. The gas burner 19 is stopped and non-heated inert gas is supplied into the furnace 2 to cool the closed space 6. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、金属製の魔法瓶、真空容器、真空二重管、真空断熱パネル、真空断熱シート等の金属製真空構造体の製造方法に関する。
【０００２】
【従来の技術】
魔法瓶等の金属製真空構造体の製造では、例えば、構成部材（例えば魔法瓶の外瓶と内瓶）により形成される閉空間を加熱しつつ排気孔から真空引きして排気し、断熱効果を得るための所定の真空度とする。その後、排気孔を封止して閉空間を密閉する。
【０００３】
【発明が解決しようとする課題】
前記金属製真空構造体の製造における閉空間の加熱排気が大気雰囲気中で行われた場合、構成部材の表面に酸化被膜が形成されるのを避けることができなかった。この酸化被膜は防錆処理や磨き加工等の後加工の妨げとなり、特に口部が小さく内部が深い瓶形状の真空容器、大判の真空断熱パネル、薄厚の真空断熱シート等の酸化被膜除去処理は困難であり、後工程が制限される。
【０００４】
特許第２７６６２１３号には、加熱用のガスバーナの破損により加熱炉中に燃焼ガスや空気が流入した場合に不活性ガスを加熱炉中に導入することが記載されている。しかし、これは故障発生時の被処理物の酸化防止や炉の損傷防止を図ったものに過ぎず、積極的に不活性ガス雰囲気中で加熱処理することを意図したものではない。
【０００５】
そこで、本発明は、金属製真空構造体の製造において構成部材の表面の酸化被膜形成を防止することを課題としている。
【０００６】
【課題を解決するための手段】
本発明は、金属製構造部材により形成された閉空間を加熱しつつ前記金属製構造体に形成された排気孔を介して排気し、前記排気孔を封止した後冷却する金属製真空構造体の製造方法において、不活性ガス雰囲気中で前記加熱排気及び前記冷却を行うことを特徴とする、金属製真空構造体の製造方法を提供する。
【０００７】
本発明に係る金属製真空構造体の製造方法では、不活性ガス雰囲気中で加熱排気及び冷却を行うので、金属製構成部材表面の酸化被膜形成を防止することができる。従って、酸化被膜の除去処理を行うことなく、防錆処理や磨き加工等を行うことができ、金属製真空構造体の後加工が容易となる。前記不活性ガスは、例えば窒素又はアルゴンである。
【０００８】
具体的には、前記金属製構造部材を加熱炉内に配置し、前記不活性ガスにより前記加熱炉内の空気をパージし、前記加熱炉内に加熱装置により加熱された不活性ガスを供給して正圧に維持し、前記閉空間を加熱しつつ排気孔を介して排気し、前記排気孔を封止し、前記加熱装置を停止して前記加熱炉内に非加熱の不活性ガスを供給して前記閉空間を冷却する。
【０００９】
あるいは、前記金属製構造部材の内部に加熱装置により加熱された前記不活性ガスを吹き込んで前記閉空間を加熱し、前記排気孔を介して前記閉空間内を排気し、前記排気孔を封止し、前記加熱装置を停止して前記構造部材の内部に非加熱の前記不活性ガスを吹き込んで、前記閉空間を冷却する。
【００１０】
【発明の実施の形態】
次に、図面を参照して本発明の実施形態について詳細に説明する。
【００１１】
（第１実施形態）
図１は本発明の第１実施形態に係る金属製真空構造体の製造方法を実行するための製造装置１を示している。
【００１２】
製造装置１は、加熱炉２を備えている。加熱炉２内には金属製真空構造体の一例である金属製の魔法瓶３が複数個（本実施形態では５個）収容される。魔法瓶３は内瓶４と外瓶５とを備えている。内瓶４と外瓶５とは口部で互いに接合されており、外瓶５と内瓶４により閉空間６が形成されている。外瓶５の底部には閉空間６を排気するための排気孔７が設けられている。また、外瓶５には閉空間６の排気後に排気孔７を封止するためのチップ管８が設けられている。各魔法瓶３のチップ管８は炉外まで延びており、真空引き用配管１１に接続されている。真空引き用配管１１は真空引き用ポンプ１２に接続されている。また、加熱炉２の外側には、各魔法瓶３のチップ管８を圧着して封止するための圧着機構１３が配設されている。
【００１３】
一端が不活性ガス供給源１５に接続された不活性ガス供給管１６が設けられている。不活性ガス供給源１５から供給される不活性ガスは、例えば、窒素やアルゴンである。不活性ガス供給管１６の他端側は複数の支管１６ａに分岐して加熱炉２内に延びている。各支管１６ａはそれぞれ加熱炉２内に配置された魔法瓶３の内瓶４の内部まで延びている。
【００１４】
加熱炉２の上部には魔法瓶３が配置された被処理物配置室１７と隔壁２ａによって隔離された加熱帯１８が設けられている。この加熱帯１８内にガスバーナ１９が燃焼ガスを噴射する。不活性ガス供給管１６の各支管１６ａは加熱帯１８を通過して被処理物配置室１７内へ延びており、不活性ガス供給源１５から供給される不活性ガスが加熱帯１８で加熱されるようになっている。
【００１５】
加熱炉２には、被処理物配置室１７と連通する排出口２ｂが設けられている。この排出口２ｂにはバルブ２１を介して圧力調整用ポンプ２２が接続されている。
【００１６】
この製造装置１による魔法瓶３の製造方法について説明すると、まず、ガスバーナ１９が停止した状態で、不活性ガス供給源１５から不活性ガス供給管１６を介して被処理物配置室１７内に常温の不活性ガスを供給する。また、バルブ２１を開弁し、圧力調整用ポンプ２２を作動させる。不活性ガス供給管１６の支管１６ａの先端は各魔法瓶３の内部に位置しているので、図１において矢印Ａで示すように、不活性ガスは各魔法瓶３の内部から被処理物配置室１７内に流入する。不活性ガス供給前に被処理物配置室１７内に充満していた空気は、不活性ガスによりパージされる。詳細には、被処理物配置室１７内の空気は、排気口２ｂからバルブ２１を経て圧力調整用ポンプ２２により排出される。
【００１７】
次に、真空引きポンプ１２を作動させ、排気孔７を介した各魔法瓶３の閉空間６の排気を開始する。排気開始後、ガスバーナ１９を作動させ、不活性ガス供給源１５からの不活性ガスを加熱帯１８で加熱して被処理物配置室１７内に供給する。また、バルブ２１の開閉及び圧力調整用バルブ２１の作動によって、被処理物配置室１７内を不活性ガスによって正圧で維持する。
【００１８】
このように加熱された不活性ガスを被処理物配置室１７内全体に充満させることにより、魔法瓶３の閉空間６を所定温度（例えば４５０℃）に加熱しつつ、排気孔７を介して各魔法瓶３の閉空間６を排気する。この加熱下での排気によって、魔法瓶３の閉空間６が所定の真空度（例えば５×１０^−６Ｔｏｒｒ）に達した後、圧着機構１３によりチップ管８を圧着する。これによって排気孔７が封止され、閉空間６が密閉される。
【００１９】
次に、ガスバーナ１９を停止して、不活性ガス供給源１５から不活性ガス供給管１６を介して非加熱の不活性ガスを被処理物配置室１７内に供給し、閉空間６を冷却する。この際、バルブ２１を開弁し、圧力調整用ポンプ２２によって被処理物配置室１７内の不活性ガスを連続的に排気する。閉空間６の温度が所定温度（例えば１５０℃）に低下するまで、この不活性ガスによる冷却を継続する。
【００２０】
本実施形態では、以上のように被処理物配置室１７内に不活性ガスを充満させ、不活性ガス雰囲気中で魔法瓶３の閉空間６の加熱及び冷却を行うので、内瓶４や外瓶５の表面における酸化被膜形成を防止することができる。特に、不活性ガス供給管１６の支管１６ａの先端が魔法瓶３の内瓶４の内部に延びており、不活性ガスは各魔法瓶３の内部から被処理物配置室１７内へ流出するので、魔法瓶３の内瓶４及び外瓶５の表面に確実に不活性ガスを供給して酸化被膜形成を防止することができる。本実施形態の製造方法により製造された魔法瓶３は内瓶４及び外瓶５に酸化被膜が形成されてないので、防錆処理や磨き加工等の後工程を容易に行うことができる。
【００２１】
（第２実施形態）
図２及び図３は、本発明の第２実施形態に係る金属製真空構造体の製造方法を実行するための製造装置１を示している。
【００２２】
第１実施形態では複数個の魔法瓶３を加熱炉２に設けた一つの被処理物配置室１７内に配置したが、第２実施形態では製造装置１の内部空間は仕切壁１ｂにより複数の被処理物配置室２３に仕切られており、各被処理物配置室２３に１個づつ配置される魔法瓶３に対して個別に加熱排気及び冷却を行うことができる。また、第１実施形態では魔法瓶３はチップ管８（図１）を備えるが、第２実施形態では排気孔７に孔付きのろう材９が取り付けられている。
【００２３】
不活性ガス供給源１５に接続された不活性ガス供給管１６の各支管１６ａの先端は、被処理物配置室２３に配置された魔法瓶３の内瓶４の内部に位置している。また、各支管１６ａの内部には、電源２４から電力供給されるとジュール熱を発生する電気ヒータ２７が配置されている。
【００２４】
被処理物配置室２３の底壁２３ａには開口２３ｂが設けられている。この開口２３ｂ内に魔法瓶３の下部が挿入されている。外瓶５と開口２３ｂの周壁との間には隙間が設けられており、この隙間を介して被処理物配置室２３の内部と大気が連通している。
【００２５】
開口２３ｂから露出している魔法瓶３の外瓶５の底面と排気加熱機構３０の上面との間には環状のシール部材２５が介在しており、排気孔７を含む密閉空間が形成されている。排気加熱機構３０に設けられた真空引き用流路３１は、一端がこの密閉空間と連通し、他端が真空引き用ポンプ１２に接続されている。また、排気加熱機構３０には、この密閉空間を挟んで排気孔７と対向するように電磁誘導加熱用のコイル３２が配置されている。
【００２６】
この製造装置１による魔法瓶３の製造方法について説明すると、まず、真空引き用ポンプ１２を作動させ、排気孔７及び真空引き流路３１を介した閉空間６内の排気を開始する。次に、電気ヒータ２７を作動させ、不活性ガス供給源１５から不活性ガス供給管１６を介して被処理物配置室２３内に加熱された不活性ガスを供給し、閉空間６内を所定温度（例えば５５０℃）に加熱する。この際、不活性ガス供給管１６の支管１６ａの先端は魔法瓶３の内部に位置しているので、図２及び図３において矢印Ｂで示すように、加熱された不活性ガスは魔法瓶３の内部から被処理物配置室２３内に流入する。被処理物配置室２３内の不活性ガスは、開口２３ｂを介して製造装置１の外部に流出する。
【００２７】
閉空間６内を前記の所定温度に維持しつつ、真空引き用ポンプ１２を作動させ、排気孔７及び真空引き流路３１を介した閉空間６内の排気を継続する。この加熱下での排気によって、魔法瓶３の閉空間が所定の真空度（例えば５×１０^−６Ｔｏｒｒ）に達した後、電源２８からコイル３２に電力を供給して磁界を生じさせ、外瓶２の底部に発生する渦電流によってろう材９を電磁誘導加熱する。溶融したろう材９によって排気孔７が封止され、閉空間６が密閉される。
【００２８】
次に、電源２４からの給電を停止して電気ヒータ２７による加熱を停止し、不活性ガス供給源１５から不活性ガス供給管１６を介して非加熱の不活性ガスを被処理物配置室２３内に供給し、閉空間６を冷却する。この際、非加熱の不活性ガスは魔法瓶３の内部から被処理物配置室２３内に流入し、開口２３ｂを介して製造装置１の外部に流出する。
【００２９】
本実施形態では、以上のように被処理物配置室２３内の魔法瓶３に加熱又は冷却用の不活性ガスを供給し、不活性ガス雰囲気中で魔法瓶３の閉空間６の加熱排気及び冷却を行うので、内瓶４や外瓶５の表面における酸化被膜形成を防止することができる。本実施形態の製造方法により製造された魔法瓶３は内瓶４及び外瓶５に酸化被膜が形成されてないので、防錆処理や磨き加工等の後工程を容易に行うことができる。
【００３０】
魔法瓶の製造を例に本発明を説明したが、本発明は真空容器、真空二重管、真空断熱パネル、真空断熱シート等の他の金属製真空構造体の製造にも適用することができる。
【００３１】
【発明の効果】
以上の説明から明らかなように、本発明に係る金属製真空構造体の製造方法では、不活性ガス雰囲気中で構造部材により形成される閉空間の加熱排気及び冷却を行うので、構成部材表面の酸化被膜の形成を防止することができる。従って、酸化被膜の除去処理を行うことなく、防錆処理や磨き加工等の後加工を金属製真空構造体に施すことができ、後加工が容易となる。特に、口部が小さく内部が深い瓶形状の真空容器、大判の真空断熱パネル、薄厚の真空断熱シート等の酸化被膜除去処理が困難な金属製真空構造体の後加工が容易になる。
【図面の簡単な説明】
【図１】本発明の第１実施形態に係る金属製真空構造体の製造方法に使用する製造装置を示す概略断面図である。
【図２】本発明の第２実施形態に係る金属製真空構造体の製造方法に使用する製造装置を示す概略断面図である。
【図３】図２の製造装置の部分拡大断面図である。
【符号の説明】
１　製造装置
１ｂ　仕切壁
２　加熱炉
２ａ　隔壁
２ｂ　排出口
３　魔法瓶
４　内瓶
５　外瓶
６　閉空間
７　排気孔
８　チップ管
９　ろう材
１１　真空引き用配管
１２　真空引き用ポンプ
１３　圧着機構
１５　不活性ガス供給源
１６　不活性ガス供給管
１６ａ　支管
１７，２３　被処理物配置室
１８　加熱帯
１９　ガスバーナ
２１　バルブ
２２　圧力調整用ポンプ
２３ａ　底壁
２３ｂ　開口
２５　シール部材
２４，２８　電源
２７　電気ヒータ
３０　排気加熱機構
３１　真空引き用流路
３２　コイル[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a metal vacuum structure such as a metal thermos, a vacuum vessel, a vacuum double tube, a vacuum heat insulating panel, and a vacuum heat insulating sheet.
[0002]
[Prior art]
In the production of a vacuum structure made of metal such as a thermos, for example, a closed space formed by components (for example, an outer bottle and an inner bottle of a thermos) is evacuated and evacuated from an exhaust hole while heating to obtain a heat insulating effect. To a predetermined degree of vacuum. Thereafter, the exhaust hole is sealed to seal the closed space.
[0003]
[Problems to be solved by the invention]
When heating and evacuation of a closed space in the production of the metal vacuum structure is performed in an air atmosphere, formation of an oxide film on the surface of the component cannot be avoided. This oxide film hinders post-processing such as rust prevention and polishing, and in particular, oxide film removal processing for bottle-shaped vacuum vessels with a small mouth and deep inside, large-sized vacuum insulation panels, thin vacuum insulation sheets, etc. Difficult and limited post-processing.
[0004]
Japanese Patent No. 2,766,213 describes that when a combustion gas or air flows into a heating furnace due to breakage of a heating gas burner, an inert gas is introduced into the heating furnace. However, this is merely an attempt to prevent oxidation of the object to be processed and damage to the furnace when a failure occurs, and is not intended to positively perform heat treatment in an inert gas atmosphere.
[0005]
Therefore, an object of the present invention is to prevent the formation of an oxide film on the surface of a component in the production of a metal vacuum structure.
[0006]
[Means for Solving the Problems]
The present invention provides a metal vacuum structure that heats a closed space formed by a metal structural member, exhausts air through an exhaust hole formed in the metal structure, seals the exhaust hole, and then cools the exhaust hole. The method of manufacturing a metal vacuum structure, wherein the heating and exhausting and the cooling are performed in an inert gas atmosphere.
[0007]
In the method for manufacturing a metal vacuum structure according to the present invention, since heating and exhausting and cooling are performed in an inert gas atmosphere, formation of an oxide film on the surface of the metal component can be prevented. Therefore, it is possible to perform a rust prevention process, a polishing process, and the like without performing the removal process of the oxide film, and the post-processing of the metal vacuum structure becomes easy. The inert gas is, for example, nitrogen or argon.
[0008]
Specifically, the metal structural member is disposed in a heating furnace, the air in the heating furnace is purged with the inert gas, and an inert gas heated by a heating device is supplied into the heating furnace. To maintain a positive pressure, exhaust the air through an exhaust hole while heating the closed space, seal the exhaust hole, stop the heating device, and supply an unheated inert gas into the heating furnace. Then, the closed space is cooled.
[0009]
Alternatively, the inert gas heated by a heating device is blown into the inside of the metal structural member to heat the closed space, exhaust the inside of the closed space through the exhaust hole, and seal the exhaust hole. Then, the heating device is stopped and the unheated inert gas is blown into the inside of the structural member to cool the closed space.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described in detail with reference to the drawings.
[0011]
(1st Embodiment)
FIG. 1 shows a manufacturing apparatus 1 for executing a method for manufacturing a metal vacuum structure according to a first embodiment of the present invention.
[0012]
The manufacturing apparatus 1 includes a heating furnace 2. In the heating furnace 2, a plurality (five in the present embodiment) of metal thermos bottles 3 as an example of a metal vacuum structure are accommodated. The thermos bottle 3 includes an inner bottle 4 and an outer bottle 5. The inner bottle 4 and the outer bottle 5 are joined to each other at the mouth, and a closed space 6 is formed by the outer bottle 5 and the inner bottle 4. An exhaust hole 7 for exhausting the closed space 6 is provided at the bottom of the outer bottle 5. Further, the outer bottle 5 is provided with a chip tube 8 for sealing the exhaust hole 7 after exhausting the closed space 6. The tip tube 8 of each thermos bottle 3 extends to the outside of the furnace and is connected to a vacuum evacuation pipe 11. The evacuation pipe 11 is connected to an evacuation pump 12. In addition, a crimping mechanism 13 for crimping and sealing the chip tube 8 of each thermos bottle 3 is provided outside the heating furnace 2.
[0013]
An inert gas supply pipe 16 having one end connected to the inert gas supply source 15 is provided. The inert gas supplied from the inert gas supply source 15 is, for example, nitrogen or argon. The other end of the inert gas supply pipe 16 branches into a plurality of branch pipes 16 a and extends into the heating furnace 2. Each branch pipe 16a extends to the inside of the inner bottle 4 of the thermos 3 arranged in the heating furnace 2, respectively.
[0014]
At the upper part of the heating furnace 2, there is provided a heating chamber 18, which is separated from the processing object placement chamber 17 in which the thermos 3 is placed and the partition wall 2 a. A gas burner 19 injects a combustion gas into the heating zone 18. Each branch pipe 16a of the inert gas supply pipe 16 passes through the heating zone 18 and extends into the processing object placement chamber 17, and the inert gas supplied from the inert gas supply source 15 is heated in the heating zone 18. It has become so.
[0015]
The heating furnace 2 is provided with a discharge port 2 b communicating with the workpiece placement chamber 17. A pressure adjusting pump 22 is connected to the outlet 2 b via a valve 21.
[0016]
A method of manufacturing the thermos bottle 3 by the manufacturing apparatus 1 will be described. First, in a state where the gas burner 19 is stopped, the inert gas supply source 15 enters the processing object placement chamber 17 through the inert gas supply pipe 16 at room temperature. Supply inert gas. Further, the valve 21 is opened, and the pressure adjusting pump 22 is operated. Since the distal end of the branch pipe 16 a of the inert gas supply pipe 16 is located inside each thermos bottle 3, as shown by an arrow A in FIG. Flows into. The air filled in the processing object placement chamber 17 before the supply of the inert gas is purged by the inert gas. Specifically, the air in the processing object placement chamber 17 is exhausted from the exhaust port 2b via the valve 21 by the pressure adjusting pump 22.
[0017]
Next, the vacuum pump 12 is operated, and the evacuation of the closed space 6 of each thermos bottle 3 via the evacuation hole 7 is started. After the start of evacuation, the gas burner 19 is operated, and the inert gas from the inert gas supply source 15 is heated in the heating zone 18 and supplied into the processing object placement chamber 17. Further, by opening and closing the valve 21 and operating the pressure adjusting valve 21, the inside of the processing object placement chamber 17 is maintained at a positive pressure by the inert gas.
[0018]
By filling the entire interior of the processing object placement chamber 17 with the heated inert gas, the closed space 6 of the thermos bottle 3 is heated to a predetermined temperature (for example, 450 ° C.) while being heated through the exhaust holes 7. The closed space 6 of the thermos 3 is evacuated. After the closed space 6 of the thermos bottle 3 reaches a predetermined degree of vacuum (for example, 5 × 10 ⁻⁶ Torr) by the evacuation under the heating, the tip tube 8 is crimped by the crimping mechanism 13. Thereby, the exhaust hole 7 is sealed, and the closed space 6 is sealed.
[0019]
Next, the gas burner 19 is stopped, and an unheated inert gas is supplied from the inert gas supply source 15 through the inert gas supply pipe 16 into the processing object placement chamber 17 to cool the closed space 6. . At this time, the valve 21 is opened, and the inert gas in the processing chamber 17 is continuously exhausted by the pressure adjusting pump 22. The cooling with the inert gas is continued until the temperature of the closed space 6 decreases to a predetermined temperature (for example, 150 ° C.).
[0020]
In the present embodiment, as described above, the processing object placement chamber 17 is filled with the inert gas, and the heating and cooling of the closed space 6 of the thermos bottle 3 are performed in the inert gas atmosphere. The formation of an oxide film on the surface of No. 5 can be prevented. In particular, the distal end of the branch pipe 16a of the inert gas supply pipe 16 extends into the inner bottle 4 of the thermos bottle 3, and the inert gas flows out of the inside of each thermos bottle 3 into the workpiece placement chamber 17, so that the thermos bottle 3 An inert gas can be reliably supplied to the surfaces of the inner bottle 4 and the outer bottle 5 to prevent the formation of an oxide film. Since the thermos bottle 3 manufactured by the manufacturing method of the present embodiment has no oxide film formed on the inner bottle 4 and the outer bottle 5, it is possible to easily perform a post-process such as a rust prevention process or a polishing process.
[0021]
(2nd Embodiment)
2 and 3 show a manufacturing apparatus 1 for executing a method for manufacturing a metal vacuum structure according to a second embodiment of the present invention.
[0022]
In the first embodiment, a plurality of thermos bottles 3 are arranged in one workpiece placement chamber 17 provided in the heating furnace 2, but in the second embodiment, the internal space of the manufacturing apparatus 1 is divided into a plurality of chambers by a partition wall 1b. The processing chambers 23 are partitioned, and the heating and exhausting and cooling can be individually performed on the thermos bottles 3 arranged one by one in each of the processing chambers 23. Further, in the first embodiment, the thermos 3 is provided with a tip tube 8 (FIG. 1), but in the second embodiment, a brazing material 9 with a hole is attached to the exhaust hole 7.
[0023]
The distal end of each branch pipe 16 a of the inert gas supply pipe 16 connected to the inert gas supply source 15 is located inside the inner bottle 4 of the thermos 3 placed in the processing object placement chamber 23. Further, an electric heater 27 that generates Joule heat when power is supplied from the power supply 24 is disposed inside each branch pipe 16a.
[0024]
An opening 23b is provided in the bottom wall 23a of the processing object placement chamber 23. The lower part of the thermos 3 is inserted into the opening 23b. A gap is provided between the outer bottle 5 and the peripheral wall of the opening 23b, and the inside of the processing object arrangement chamber 23 and the atmosphere communicate with each other through the gap.
[0025]
An annular seal member 25 is interposed between the bottom surface of the outer bottle 5 of the thermos bottle 3 exposed from the opening 23b and the upper surface of the exhaust heating mechanism 30, and a closed space including the exhaust hole 7 is formed. . One end of the evacuation flow channel 31 provided in the exhaust heating mechanism 30 communicates with the closed space, and the other end is connected to the evacuation pump 12. In addition, a coil 32 for electromagnetic induction heating is disposed in the exhaust heating mechanism 30 so as to face the exhaust hole 7 with the enclosed space interposed therebetween.
[0026]
The method of manufacturing the thermos bottle 3 by the manufacturing apparatus 1 will be described. First, the vacuum pump 12 is operated to start exhausting the closed space 6 through the exhaust hole 7 and the vacuum passage 31. Next, the electric heater 27 is operated to supply the heated inert gas from the inert gas supply source 15 into the processing object placement chamber 23 via the inert gas supply pipe 16, thereby causing the inside of the closed space 6 to pass through the predetermined space. Heat to a temperature (eg, 550 ° C.). At this time, since the distal end of the branch pipe 16a of the inert gas supply pipe 16 is located inside the thermos bottle 3, the heated inert gas is removed from the inside of the thermos bottle 3 as shown by an arrow B in FIGS. Flows into the processing object placement chamber 23 from the inside. The inert gas in the processing chamber 23 flows out of the manufacturing apparatus 1 through the opening 23b.
[0027]
While maintaining the inside of the closed space 6 at the above-mentioned predetermined temperature, the vacuum pump 12 is operated and the exhaust in the closed space 6 through the exhaust hole 7 and the vacuum passage 31 is continued. After the closed space of the thermos 3 reaches a predetermined degree of vacuum (for example, 5 × 10 ⁻⁶ Torr) due to the exhaust under heating, power is supplied from the power supply 28 to the coil 32 to generate a magnetic field. Electromagnetic induction heating of the brazing material 9 is performed by eddy current generated at the bottom of the brazing material 2. The exhaust hole 7 is sealed by the molten brazing material 9, and the closed space 6 is sealed.
[0028]
Next, the power supply from the power supply 24 is stopped to stop the heating by the electric heater 27, and the non-heated inert gas is supplied from the inert gas supply source 15 through the inert gas supply pipe 16 to the processing chamber 23. To cool the closed space 6. At this time, the unheated inert gas flows from the inside of the thermos bottle 3 into the processing object placement chamber 23, and flows out of the manufacturing apparatus 1 through the opening 23b.
[0029]
In the present embodiment, as described above, an inert gas for heating or cooling is supplied to the thermos bottle 3 in the processing object placement chamber 23, and the heating and exhausting and cooling of the closed space 6 of the thermos bottle 3 are performed in an inert gas atmosphere. As a result, the formation of an oxide film on the surface of the inner bottle 4 and the outer bottle 5 can be prevented. Since the thermos bottle 3 manufactured by the manufacturing method of the present embodiment has no oxide film formed on the inner bottle 4 and the outer bottle 5, it is possible to easily perform a post-process such as a rust prevention process or a polishing process.
[0030]
Although the present invention has been described by taking the production of a thermos as an example, the present invention can be applied to the production of other metal vacuum structures such as vacuum containers, vacuum double tubes, vacuum heat insulating panels, and vacuum heat insulating sheets.
[0031]
【The invention's effect】
As is clear from the above description, in the method for manufacturing a metal vacuum structure according to the present invention, heating and exhausting and cooling of the closed space formed by the structural members in an inert gas atmosphere are performed, so The formation of an oxide film can be prevented. Therefore, post-processing such as rust prevention and polishing can be performed on the metal vacuum structure without performing the oxide film removal processing, and the post-processing is facilitated. In particular, the post-processing of a metal vacuum structure, such as a bottle-shaped vacuum container having a small mouth portion and a deep inside, a large-sized vacuum heat insulating panel, a thin vacuum heat insulating sheet, and the like, which is difficult to remove an oxide film, becomes easy.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a manufacturing apparatus used for a method for manufacturing a metal vacuum structure according to a first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view showing a manufacturing apparatus used for a method for manufacturing a metal vacuum structure according to a second embodiment of the present invention.
FIG. 3 is a partially enlarged sectional view of the manufacturing apparatus of FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 1b Partition wall 2 Heating furnace 2a Partition wall 2b Discharge port 3 Thermos bottle 4 Inner bottle 5 Outer bottle 6 Closed space 7 Exhaust hole 8 Chip tube 9 Brazing material 11 Vacuum piping 12 Vacuum pump 13 Crimping mechanism 15 Inactive Gas supply source 16 Inert gas supply pipe 16a Branch pipes 17, 23 Workpiece placement chamber 18 Heating zone 19 Gas burner 21 Valve 22 Pressure adjusting pump 23a Bottom wall 23b Opening 25 Seal members 24, 28 Power supply 27 Electric heater 30 Exhaust heating mechanism 31 Vacuum passage 32 Coil

Claims

In a method for manufacturing a metal vacuum structure, a closed space formed by a metal structural member is heated and exhausted through an exhaust hole formed in the metal structure, and the exhaust hole is sealed and then cooled. ,
A method for producing a metal vacuum structure, wherein the heating and exhausting and the cooling are performed in an inert gas atmosphere.

Placing the metal structural member in a heating furnace,
Purging the air in the heating furnace with the inert gas,
Supplying an inert gas heated by a heating device into the heating furnace to maintain a positive pressure, and exhausting the closed space through an exhaust hole while heating the closed space;
Sealing the exhaust hole,
The method for manufacturing a metal vacuum structure according to claim 1, wherein the heating device is stopped, and an unheated inert gas is supplied into the heating furnace to cool the closed space.

Blowing the inert gas heated by a heating device into the inside of the metal structural member to heat the closed space, and exhausting the closed space through the exhaust hole,
Sealing the exhaust hole,
The method for manufacturing a metal vacuum structure according to claim 1, wherein the closed space is cooled by stopping the heating device and blowing the unheated inert gas into the inside of the structural member.