JPH0534309B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for sealingly bonding ceramic members, and particularly to a method for sealingly bonding ceramic members by local heating.

(Prior Art) Conventionally, hermetic bonding that requires airtightness between ceramic members has been carried out by an overall heating method, preferably by applying low-melting glass to the bonding surfaces and heating the entire assembly in a heating furnace. It was common.

(Problem to be Solved by the Invention) However, when heating and sealing the entire ceramic container as described above, a large heating device is required, and heating the entire container results in large energy loss. Depending on the substance contained in the container, the quality of the stored material may change due to overall heating.
There was a problem in which it was impossible to heat the entire product when it was sealed. In particular, when trying to seal and store low-level radioactive waste generated from nuclear power plants in ceramic containers, conventional whole heating systems have been problematic.

An object of the present invention is to solve the above-mentioned problems and to provide a method for sealing a ceramic lid and a glass by local heating between the ceramic lid and the container, which can seal between the ceramic members without heating the entire body. be.

(Means for Solving the Problems) In the glass bonding method between ceramic members of the present invention, when sealing a ceramic container with a ceramic lid, the angle between the tip of the ceramic container and the peripheral edge of the ceramic lid is 50°. ~85°,
The ceramic lid is set on the ceramic container so that the thickness of the tip of the ceramic container is less than 1/2 of the wall thickness of the container, and the heated joint is heated locally with a burner while rotating the joint. The method is characterized in that glass powder or molten glass is supplied to the container, and the ceramic container is sealed with a ceramic lid.

(Function) In the above-mentioned configuration, after the burner heats only the joint part locally, for example, by supplying glass powder and melting it, or by supplying molten glass, it is possible to avoid heating the whole part. Bonding with sufficient sealing performance can be achieved by only local heating.

(Example) Figures 1a to 1d are diagrams showing the glass sealing method of the present invention in the order of steps. In this embodiment, first, an object to be sealed, such as radioactive waste, is placed in a ceramic container 1, and then the ceramic lid 2 is attached leaving a gap at the joint 3. Next, the first
As shown in Figure a, the ceramic container 1 and ceramic lid 2 near the joint 3 are heated by flames from two burners 4-1 and 4-2 provided on the joint 3. Ordinary propane gas burners can be used as the burners 4-1 and 4-2, and in order to achieve uniform heating, the burners 4-1 and 4-2 are rotated at low speed, and the ceramic container 1 is rotated at an even lower speed in the opposite direction. It is rotating. Also, when heating with a burner,
It is preferable to cover the parts other than the joint part 3 with a heat insulating material.

The heating rate in burner heating is preferably controlled to 90° C./hr or less, since cracks may occur if the heating rate is too fast. Further, the holding temperature of the joint portion 3 after heating varies depending on the melting point of the glass used, but as an example, when using a low melting point glass with a melting point of about 400°C, it is preferable to hold it at 500 to 520°C for 1.5 to 2 hours. At this time, if the holding time is too short, a temperature difference may occur between the ceramic container 1 and the ceramic lid 2 near the joint 3, which may cause cracks.

Next, as shown in FIG. 1b, preferably low melting point glass powder is supplied to the joint 3 from the powder supply port 5, or melted low melting point glass is preferably supplied from the melt injection port 6 as shown in FIG. 1c. Pour into the joint 3. 1st
When powder is supplied to the joint 3 as shown in Figure b, it is necessary to melt it using the heat of the joint 3, so if the powder is fine, it may cause problems in terms of meltability, fluidity, etc. It is preferable to use granules with a particle size of about 5 μm. Although commercially available low melting point glasses can be used, it is preferable to use one whose coefficient of thermal expansion is as close as possible to the coefficients of thermal expansion of the ceramic container 1 and the ceramic lid 2. Further, in both cases of FIGS. 1b and 1c, it is preferable to rotate the ceramic container 1 at a low speed.

As shown in Figure 2, the shape of the joint is such that the angle α of the tip of the ceramic container and the periphery of the lid are both 50 to 85 degrees, and the wall thickness t of the joint at the tip of the ceramic container is equal to that of the container. It is preferable that the thickness be 1/2 or more of the wall thickness T, and the shape is such that the surface to be bonded can be uniformly heated and glass bonding can be easily performed. This has the effect of reducing thermal damage to the bonded material due to thermal stress.

Finally, the low melting point glass is supplied to the joint 3 and then cooled to obtain a container in which the joint 3 is sealed with the low melting glass 7 as shown in FIG. 1d. Incidentally, no cracks occurred in the obtained container.

The present invention is not limited only to the embodiments described above, and numerous modifications and changes are possible. For example, in the embodiment described above, an example was shown in which two burners were used, but the number of burners is not limited to two, and it is also possible to further increase the number. Further, the material of the ceramic container is not particularly limited, and it goes without saying that any ceramic can be used.

(Effects of the Invention) As is clear from the detailed explanation above, according to the glass sealing method of the present invention, after the joint is locally heated with a burner, for example, low melting point glass powder is supplied or melted glass powder is supplied. By supplying melting point glass, a ceramic container and a ceramic lid can be hermetically bonded together without heating the entire container. Therefore, large-scale heating equipment is not required, energy loss required for heating is small, and even if the object to be stored is radioactive waste, etc., which would be inconvenient if heat is applied, it can be suitably sealed in a ceramic container.

[Brief explanation of the drawing]

1A to 1D are diagrams showing the glass sealing method of the present invention in the order of steps, respectively, and FIG. 2 is a diagram showing an enlarged view of the shape of the joint portion. DESCRIPTION OF SYMBOLS 1...Ceramic container, 2...Ceramic lid, 3...Joint part, 4-1, 4-2...Burner,
5... Powder supply port, 6... Melt injection port, 7... Low melting point glass.

Claims (1)

[Claims] 1. When sealing a ceramic container with a ceramic lid, the angle between the tip of the ceramic container and the periphery of the ceramic lid is 50 to 85 degrees,
The ceramic lid is set on the ceramic container so that the thickness of the tip of the ceramic container is less than 1/2 of the wall thickness of the container, and the heated joint is heated locally with a burner while rotating the joint. 1. A method for bonding glass between ceramic members, comprising: supplying glass powder or molten glass; and sealing the ceramic container with a ceramic lid.