JPS607823A - Production of metal vacuum double container - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention Technical Field The present invention provides a metal vacuum double container, particularly a metal inner container and an outer container with a plating layer on the inner wall surface of a vacuum insulation space formed between an inner container and an outer container to improve the radiation coefficient. The present invention relates to a double-walled metal vacuum container with a /J% reduction in insulation properties.

Prior art In order to prevent heat loss or heat intrusion due to radiation between the inner and outer containers of a metal vacuum double container, the radiation coefficient is reduced by interposing a heat shield plate or by plating or polishing the wall surface. is already well known, but each of these steps is only performed separately, making the work complicated and costly. To solve this problem, we installed a heat shield made of a metal plate with a higher melting point than the brazing filler metal that seals the inner and outer containers under vacuum heating, and cooled the entire container after the vacuum heating process completed melting. A method for manufacturing a heat shielding plate in which a metal material is deposited on the inner and outer container wall surfaces corresponding to the heat shielding plate is known from Japanese Patent Laid-Open No. 110219/1983.

However, the heat shield plate has a triple structure with the inner and outer containers,
This alone makes the structure of the container more complicated and heavier. In addition, the heat shield plate must be formed into a container shape that is almost similar to the inner and outer containers, and must be fitted to the inner and outer containers, which simplifies the manufacturing process.
Still not fully satisfied due to cost reduction. Moreover, the inner and outer surfaces of the heat shield plate cause gas to remain, and the area where the gas remains doubles, making it difficult to maintain a predetermined degree of vacuum.

Purpose This invention provides a metal vacuum double wall structure that can eliminate the above-mentioned conventional drawbacks in a structure that has a plating layer on both the inner wall surfaces formed by the inner and outer containers of a vacuum insulation space so as to double reduce the radiation coefficient. The object of the present invention is to provide a method for manufacturing a container.

Structure In this invention, a metal outer container and a metal inner container whose outer peripheral surface has been previously formed with a plating layer are combined into a double container.

Next, along with a vacuum sealing step of evacuating and sealing the space between the inner container and the outer container, or in a loose vacuum sealing process, a vapor deposition plating process is performed on the inner circumferential surface of the outer container using the plating metal as a vapor deposition source.

Various known methods such as a vacuum evaporation method, a sputtering method, and an ion blating method can be used for the vapor deposition plating process.

It is desirable that the plating layer pre-formed on the outer circumferential surface of the inner container has a layer thickness that takes into account the plating layer deposited on the inner circumferential surface of the outer container. In this case, electrical treatment is performed by insulating the inner container and the outer container with an airtight joint interposed with an insulator such as ceramic.

The plating layer previously formed on the outer circumferential surface of the inner container and the vapor-deposited plating layer formed on the inner circumferential surface of the outer container double reduce the radiation coefficient of the metal vacuum double container, reducing heat loss and Doubles the heat intrusion suppression effect.

The plating layer pre-formed on the outer circumferential surface of the inner container can be applied to the inner and outer surfaces of the outer container already combined with the inner container, without increasing the number of containers or members to be combined in the double-metal vacuum container. To provide a deposition source for vapor deposition plating that is applied in conjunction with or subsequent to a vacuum sealing process between containers.

Embodiment Referring to FIG.
An embodiment will be described in which the inner circumferential surface of the metal outer container 3 is subjected to vapor deposition plating treatment using the plating layer 2 formed on the outer circumferential surface as a vapor deposition source.

The metal inner container 1 and outer container 3 are made of, for example, a stainless steel plate that is heat insulating and has low thermal conductivity. The inner container l has a plating layer 2 formed on its outer peripheral surface in advance,
Since it is an outer peripheral surface, it can be easily formed by any desired method such as electroplating and various vapor deposition plating, including the simplest method of immersion plating in a plating solution or chemical plating. The outer container 3 has a body 3a and a bottom 3b formed as separate bodies, and the body 3a is connected to the inner container 1 having the plating layer 2.
After fitting and combining, the body 3a and the bottom 3b are hermetically sealed 4 and integrated by welding or the like, and the inner and outer containers 1.3 are assembled into a double container. These inner and outer containers 1 and 3 are integrated by airtightly joining 4 their lip fitting portions by welding or the like.

A copper tip tube 5 is provided on the bottom 3b of the outer container 3 in an airtight manner 4 by welding or the like. The tip tube 5 may be integrally formed with the bottom portion 3b or may be placed at a desired position in the outer container 1.

The space between the inner container 1 and the outer container 3 is evacuated and sealed by cold welding and closing the chip tube 5 under a predetermined degree of vacuum by suction and exhaust through the chip tube 5, thereby creating a vacuum insulation space 6. It is said that

The vacuum sealing process for forming this vacuum insulation space 6 is usually
It is heated under appropriate conditions. It activates gas components that tend to remain in the rough surface recesses and corners such as the metal surfaces and joints 4 in the space between the inner and outer containers 1.3, making it easier to be sucked and exhausted. This is to activate a getter for adsorbing residual gas (not shown) disposed between them to prevent a decrease in the degree of vacuum due to residual gas in the vacuum heat insulating space 6 after vacuum sealing.

Therefore, by performing this heating at a temperature that can evaporate the metal material forming the plating layer 2 on the outer circumferential surface of the inner container 1, activation of the gas component and getter is promoted and the getter formed on the outer circumferential surface of the inner container 1 is heated. Vapor deposition plating is performed on the inner peripheral surface of the outer container 3 using the plating layer 2 as a vapor deposition source, together with the vacuum sealing process between the inner and outer containers 1 and 3, and the inner peripheral surface of the outer container 3 is also coated as shown by the imaginary line in FIG. A plating layer 7 is formed.

The plating layers 2 and 7 double the radiation coefficient of the metal vacuum double container 8 formed as described above, and reduce the radiation coefficient to the outside! It is formed to prevent loss and heat intrusion from the outside, and suitable materials include metals such as silver, copper, chromium, nickel, and tin, or alloys based on these metals.

An appropriate heating temperature that can evaporate the materials may be set based on the relationship between the materials used and the degree of vacuum created by exhaust between the inner and outer containers 1.3.

For example, Figure 2 shows the pressure and humidity diagrams for representative materials, silver, copper, and chromium.
Ou 10r respectively. In this figure, the respective lines Ag, Cu for each material.

The high temperature side of Or indicates the vapor region, and the degree of vacuum is 10”
Assuming a Torr table, the required heating temperature is approximately 820° C. for silver, approximately 1020° C. for copper, and approximately 1130° C. for chromium.

By the way, the vertical total emissivity of each material is 0.00 for silver.
44-0.02, 0005-0.018 for copper, 0.058-006 for chromium, 0.44-0.36 for the rough surface of stainless steel 5US-304, and 0.44 for the polished surface. 074, the double emissivity reduction effect of the plating layers 2 and 7 on the stainless steel vacuum double container 8 is large, and the heat insulation properties are improved accordingly.

In addition, there are materials such as nickel that have a small emissivity of 0.022 to 0.04, and various materials can be used effectively, and it goes without saying that alloys based on each material may also be used. .

In addition, the plating layer 2 is used as the vapor deposition source and the inner circumferential surface of the outer container 3 is vapor-deposited after the vacuum sealing process between the inner and outer containers 1 and 3 is performed in a normal temperature range, and then the temperature is raised to the required temperature for vapor deposition. Plating can also be performed, and even in this case, the temperature can be raised easily and quickly from the vacuum sealing process temperature to the required temperature, and vapor deposition plating can be achieved just by raising the temperature, so it is especially suitable for systems with complicated processes. The process does not take a long time and can be said to be a simultaneous process in the vacuum sealing process.

On the other hand, the vacuum sealing process between the inner and outer containers 1.3 is carried out by the so-called vacuum brazing method, in which the final joints (or all necessary joints) are brazed in a vacuum space that has reached a predetermined degree of vacuum. In this case, vapor deposition plating on the inner circumferential surface of the outer container 3 can be performed in the same manner using the vacuum vapor deposition method described above. In the vacuum brazing method, heating for gas release and activation of the getter and heating of the soldering pot are performed in the vacuum space, and in particular, the temperature of the wax liquid is determined by using the plating layer 2 as a deposition source and the outer container. 3. The temperature required for vapor deposition plating on the inner peripheral surface has been reached, and vapor deposition plating is achieved during the normal vacuum sealing process between the inner and outer containers 1 and 3, and the vacuum sealing process time using the vacuum brazing method is extremely short. Coupled with this, the productivity of the metal vacuum double container 8 having the plating layers 2 and 7 is extremely high.

In the case of this embodiment using the vacuum brazing method, the metal material for the plating layer 2 must be selected to have a melting point higher than the melting point of the brazing filler metal used in the vacuum brazing method, preferably higher than the temperature of the brazing fluid. As a brazing material, 1
Various types of solder such as silver solder, brass solder, aluminum solder, phosphor solder, and nickel solder can be selected and used.

Next, with reference to FIG. 3, a description will be given of an example of a case in which the inner peripheral surface of the outer container 3 is vapor-deposited and plated by sputtering using the plating layer 2 on the outer periphery of the inner container 1 as a vapor deposition source.

The inner container 1 and the outer container 3 are electrically insulated by four airtight joints that are brazed together with an insulating material such as ceramic 11 interposed therebetween. In this state, the cathode of the high-voltage DC vaporization source power supply 12 is connected to the inner container 1, which has the plating layer 2 formed on the outer circumferential surface in advance, and the anode of the power source 12 is connected to the outer container 3, respectively. During or after the completion of the vacuum sealing process between the inner and outer containers 1 and 2, a voltage is applied for a necessary period of time to perform vapor deposition plating using the plating layer 2 on the outer peripheral surface of the inner container 1 as a vapor deposition source on the inner surface of the outer container 3. The power source 12 can be replaced with a high frequency power source.

In this case, the plating layer 2 as a vapor deposition source is used as a target in a sputtering method, and metal material atoms are heated and evaporated by ions formed between the inner and outer containers 1.3.
It is ejected and vaporized (pseudo-vaporization) at nearly 0 times the speed,
Moreover, since the inner circumferential surface of the outer container 3 collides with the inner peripheral surface of the outer container 3 in an accelerated state due to the electric attraction effect, a high-density plating layer 7 with good adhesion can be obtained in a very short time with a sufficient layer thickness. It will be done. The application of a negative voltage to the outer container 3 by cathode connection of the power source 12 may be omitted, and if the vacuum sealing process is performed in the evaporation temperature range of the plating layer 2, the plating process using the vacuum evaporation method also proceeds at the same time.

Furthermore, with reference to FIG. 4, an example of a case where the inner circumferential surface of the outer container 3 is vapor-deposited and plated by using the plating layer 2 on the outer circumferential surface of the inner container 1 as a vapor deposition source will be described with reference to FIG.

The inner and outer containers 1 and 3 are electrically insulated as in the case of the sputtering method. An evaporation source power source 21 such as a high frequency power source is connected to the inner container 1, and an anode of a high voltage DC power source 22 is connected to the inner container 1, and a cathode of the power source 22 is connected to the outer container 3, respectively. Then, during or after the vacuum sealing process between the inner and outer containers 1.3, electricity is applied from the power source 21 to the plating layer 2, which is the vapor deposition source, through the inner container 1 to evaporate the metal material of the plating layer 2. The vapor plating process is performed by applying different polar charges to the inner and outer containers 1 and 3 to ionize the evaporated atoms and causing them to accelerate and collide and adhere to the inner peripheral surface of the outer container 3.

In this case, the evaporation of the plating layer 2 and the adhesion of the evaporated atoms to the inner circumferential surface of the outer container 3 are most active, and a plating layer 7 with better adhesion and higher density is obtained than in the case of the tuttering method. . Further, if the vacuum sealing process is performed in the evaporation temperature range of the plating layer 2, it can be expected that the evaporation of the plating layer 2 will be accelerated, and the formation speed of the plating layer 7 can be increased. may be omitted.

Effects According to the present invention, a metal outer container and a metal inner container whose outer peripheral surface has been previously formed with a plating layer are combined into a double container,
At the same time or after the vacuum sealing step of evacuating and sealing the space between the inner container and the outer container, vapor deposition plating treatment is performed on the inner peripheral surface of the outer container using the plating layer as a vapor deposition source. The vacuum double container made of metal has a plating layer on both inner walls of the vacuum insulation space formed by the method, and the emissivity is doubled. It can be easily and inexpensively manufactured without the problem of a decrease in the predetermined degree of vacuum over time due to an increase in the gas residual area.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram when applying the vacuum evaporation method of this invention, Fig. 2 is a vapor pressure diagram of main plating materials, Fig. 3 is an explanatory diagram when applying the sputtering method, and Fig. 4 is an explanatory diagram when applying the sputtering method. It is an explanatory diagram when applying an ion brating method. l... Metal inner container, 2.7... Plating layer, 3...
Metal outer container, 4...airtight joint, 5...chip tube,
6...Vacuum insulation space, 8...Metal N vacuum double container Applicant: Agent Tiger Thermos Co., Ltd. Go Ayumu - Keiji

Claims (3)

[Claims] (1) A vacuum sealing process in which a metal outer container and a metal inner container with a plating layer pre-formed on the outer circumferential surface are combined into a double container, and the space between the inner container and the outer container is evacuated and sealed. After sealing, a method for manufacturing a metal vacuum double container, characterized in that vapor deposition plating is performed on the inner circumferential surface of the outer container using the plating metal as a vapor deposition source. (2) The method for manufacturing a metal vacuum double container according to claim 1, wherein the vapor deposition plating treatment on the inner circumferential surface of the outer container is performed by a vacuum evaporation method. (3) The method for manufacturing a metal vacuum double container according to claim 1, in which the vapor deposition plating treatment on the inner peripheral surface of the outer container is performed by a sputtering method. (4) The vapor deposition plating treatment on the inner peripheral surface of the outer container is performed by a sputtering method. , a method for manufacturing a metal vacuum double container according to claim 1, which is performed by an ion blating method.