JPH0673270B2 - Distortion method for glass structure - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a strain relief method for a glass structure in which a neck of a cathode ray tube and a funnel are connected.

[Technical background of the invention and its problems] A cathode ray tube, especially a color cathode ray tube, is provided in an envelope including a neck, a funnel and a panel, an explosion-proof band wound around the envelope, and the envelope. If an electron gun or the like is provided and various defects occur, the envelope is collected. The method is to remove the explosion-proof band, crack a part of the exhaust pipe or the neck, introduce air, and use an acid solution or heat to separate the funnel and the panel. Next, after separating the neck or the boundary between the neck and the funnel, a new neck is re-welded to the separated portion to form a glass structure composed of the neck and the funnel. Since this re-fusion is performed by heating the neck or the boundary portion with the burner, residual cooling occurs in the vicinity of the boundary portion between the neck and the funnel if it is cooled as it is. This residual strain is removed by heating the neck (1) and the funnel (2) by an electric furnace (3) while supporting the neck (1) of the glass structure with the neck (1) facing downward as shown in FIG. However, as shown in FIG. 2, since the funnel must be arranged with the upper opening facing up, heat is radiated upward from the inner surface even if the portion for removing strain is externally heated. As shown by the broken line in FIG. 3, the temperature of the funnel portion (above the welded portion) cannot be raised to the required temperature (strain removal temperature). Further, when the power of the heater is increased, the neck portion is overheated, making it impossible to perform optimum simultaneous annealing of both the funnel portion and the neck portion.

As a result, there is a possibility that damage may occur due to residual strain during the subsequent CRT assembly process or during use of the CRT, resulting in not only economical loss but also a serious accident such as a fire.

[Object of the Invention] The present invention has been made in order to solve the drawbacks of the conventional methods, and an object of the present invention is to provide a method for removing strain in a glass structure that does not cause cracks.

[Summary of the Invention] The present invention is a method for strain relief of a glass structure composed of a neck and a funnel, wherein the neck or the funnel is heated and melted at the boundary between the neck and the funnel, and the glass structure is supported with the neck facing downward. A method for straining a glass structure, comprising heating a neck part and a part of the funnel part from the surroundings in a state where a heat insulating lid is arranged inside the funnel part having an open upper part.

[Examples of the Invention] FIG. 1 is a view for explaining a method of removing strain of a glass structure according to the present invention. A glass structure including a neck (1) and a funnel (2) is batched so that the neck (1) faces downward. Put in the electric furnace (3) of mold, neck (1) and funnel (2)
This part is held outside the funnel so that it can be heated in order to remove the residual strain that has occurred. The electric furnace has a heater inside, and can heat the glass structure to a temperature required for strain relief. It is better to provide a heat resistant lid on the upper part of the electric furnace in order to improve heating efficiency.

The structure up to this point is the same as the conventional structure, but in the present invention, a heat insulating lid (4) is further provided inside the funnel (2) above the electric furnace (3).

The effect of the heat retaining lid will be described below. Fig. 3 shows the temperature of each part when the glass structure is heated in an electric furnace. The thin line is measured at point A (inside the funnel), the middle line is at point B (outside the funnel), and the thick line is at point C (outside the neck). Indicates temperature. The solid lines show the case of the present invention, and the broken lines show the case of the conventional example.

The heat-insulating lid (4) is made of aluminum, for example, and the lower surface is about 85 mm above the boundary of the neck weld and 25 mm above the electric furnace upper surface.
It was installed on the upper part of mm.

By disposing the heat retaining lid inside the funnel, heat release from the inside of the funnel can be suppressed, so that it is possible to effectively raise the temperature of the funnel, particularly the upper portion of the welded portion, up to the strain removal temperature. As a result, the power of the heater can be suppressed, the temperature difference between the funnel and the neck can be suppressed to a low level without overheating the neck, and both can be set to appropriate strain removal temperatures.

By the method of the present invention, the residual strain of the glass structure subjected to strain relief is reduced to the strength of the safety region, accidents such as cracks are eliminated, and proper strain removal treatment using a batch type electric furnace can be realized. It has become possible. This is possible without using a large continuous heating furnace and the like, and the economic effect thereof is great.

It should be noted that although the position of the heat retaining lid (4) does not substantially affect the strain characteristics even if it is moved up and down, it must be above the strain generating portion. Further, the material is not limited to aluminum, and any other material having heat resistance can be used.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a strain relief method for a glass structure of the present invention, FIG. 2 is a diagram for explaining a conventional method, and FIG. 3 is a diagram showing temperatures of respective parts when the glass structure is heated. 1 ... Neck, 2 ... Funnel 3 ... Electric furnace, 4 ... Insulation lid

Claims (1)

[Claims] 1. A method for strain relief of a glass structure composed of a neck and a funnel, wherein a neck or a boundary between the neck and the funnel is heated and melt-processed, wherein the glass structure is supported with the neck facing downward, and the upper part is opened. A method for straining a glass structure, comprising heating a neck part and a part of the funnel part from the surroundings in a state where a heat insulating lid is arranged inside the funnel part.