JPH1045417A - Method for cooling hollow glass formed body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for cooling a hollow glass formed body which solves various problems associated with forming and solves the deficiency of the cooling capacity of a panel while preventing the deformation of the inside surface of the panel by an air pressure by optimizing the temp. distribution at the time of cooling the panel. SOLUTION: Fused glass is supplied to a lower die 4 and an upper die is lowered to press form this fused glass, following which the upper die is risen to open the dies and air is blown from a duct having an annular blow-off port 3 to the hollow glass formed body 5 in the lower die 4 to cool the formed body. This duct is formed of double structures consisting of an outside pipe 1 and an inside pipe 2. This inside pipe 2 is fixed by mounting its circumference at the outside pipe 2. The annular blow-off port 3 is disposed between these two pipes. The cross sectional shape of the annular blow-off port 3 is selected by the shape of the hollow glass formed body 5 to be cooled. The shape may be a elliptic shape or an approximately rectangular shape in addition to a circular shape. In a more preferable embodiment, the central part at the front end of the duct enclosed by the annular blow-off port 3 of the duct is provided with a pooling part 6 for the air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hollow glass product such as a panel for a cathode ray tube, by improving the temperature distribution at the time of cooling a glass molded body immediately after pressure molding, and efficiently producing the same.

[0002]

2. Description of the Related Art In the production of glass products, press molding is a widely used method. Above all, a certain amount of molten glass is supplied to the lower mold, and then the upper mold is lowered and press-formed, then the upper mold is raised to separate from the lower mold and the molded body, that is, the mold is opened, and then the lower mold is opened. It is common to take out the molded body after cooling it in the mold.

A typical example of this process is a press forming process of a panel which is a main glass part of a cathode ray tube.
First, a predetermined amount of molten glass lump called a gob is supplied to a lower mold. The lower mold filled with the gob is then transported to a press position, where the upper mold is lowered and the gob is pressed into a panel shape. Although the glass is rapidly cooled by the press, the glass is continuously cooled in the lower mold until the temperature at which the panel can be taken out after the upper mold is raised and the mold is opened.

[0004] This cooling is carried out sequentially to a plurality of cooling positions for each lower die. Therefore, the contact surface of the panel with the lower mold is cooled by the lower mold, and the surface not in contact with the mold is cooled by blowing air from above.

[0005] In this case, the side of the panel immediately after molding is deformed and falls down inside. Therefore, while the panel is still hot and soft, a means called an air former for preventing the panel from being deformed by blowing air force is used. The cooling is performed with an emphasis on preventing the side portion from falling down, rather than the cooling efficiency, and thereafter, the cooling is performed with an emphasis on the cooling efficiency. In the latter cooling step, cooling air is usually blown onto the panel from a duct having a circular cross section.

[0006] The panel sufficiently cooled to such a state that deformation in subsequent handling does not pose a problem is taken out of the lower mold and sent to the next step, and the lower mold after taking out the panel is again put into the next gob. Sent to the gob supply position to receive

As described above, the steps of glass supply → press → cooling by air former → cooling by duct → panel removal → next glass supply are performed by forming the panel by sequentially transferring the lower molds to the respective positions. Is done.

[0008]

In the panel forming process, when the cycle time from the supply of the gob to the removal of the panel is to be reduced in order to increase the productivity, the cooling capacity of the panel per unit time is increased. Therefore, the air flow is increased in an attempt to increase the cooling by the duct.

However, since the conventional duct has a general cylindrical shape, the center of the panel is cooled intensively, while not only the cooling amount for the entire panel is insufficient, but also the temperature distribution of the panel deteriorates, and In addition, various molding problems such as deterioration of mold release and abnormal curvature of the inner and outer surfaces of the panel occur. Also, if the air flow rate is excessively increased to increase the cooling amount, the inner surface of the panel is deformed by the air pressure.

SUMMARY OF THE INVENTION The present invention solves various problems in molding by optimizing the temperature distribution during cooling of the panel, and solves the insufficient cooling capacity of the panel while preventing the inner surface of the panel from being deformed by air pressure.

[0011]

SUMMARY OF THE INVENTION According to the present invention, a molten glass is supplied to a lower mold, and then the upper mold is lowered and press-formed, then the upper mold is raised to open the mold, and the hollow glass in the lower mold is opened. A method for cooling a hollow glass molded body, characterized in that the molded body is cooled by blowing air from a duct having an annular outlet.

That is, as shown in FIG. 1, the present invention uses a duct having an annular outlet 3 to cool a hollow glass molded article 5 in a lower mold 4 when the hollow glass molded article 5 is cooled. It is an object of the present invention to efficiently cool a peripheral side portion from a peripheral corner portion where cooling is required, to optimize a cooling distribution, and to shorten a cooling time.

As is clear from FIGS. 1 and 2, the duct has a double pipe structure comprising an outer pipe 1 and an inner pipe 2. The inner pipe 2 is not shown, but its periphery is fixed to the outer pipe 1. And
An annular outlet 3 is provided between these two tubes. Annular outlet 3
Can be appropriately selected according to the shape of the hollow glass molded body 5 to be cooled, and may be an elliptical shape or a substantially rectangular shape in addition to the circular shape shown in the figure.

Further, according to the present invention, the direction of air blowing can be controlled by the annular outlet structure at the tip of the duct, so that the cooling rate for the glass compact can be controlled. In order to cool the peripheral portion from the corner portion of the hollow glass molded body more efficiently, it is desirable that the tip of the inner tube 2 is slightly protruded from the outer tube 1 as shown in the figure. However, the distal ends of the outer tube 1 and the inner tube 2 can be selectively set to the same level or the inner tube 2 can be retracted from the distal end of the outer tube 1 depending on the use condition.

The outlet structure of the duct affects the direction of the cooling air flow. In addition to the relative movement of the distal ends of the outer tube and the inner tube as described above, optimization of the air flow can be achieved by changing the shape of the distal ends of these inner and outer tubes that substantially form the annular outlet. FIG. 3 shows an example. The distal end of the outer tube 1 is bent outward, and the distal end of the inner tube 2 is bent inward, so that the blowing width of the air flow is enlarged and the air flow is smooth.

Further, in a preferred embodiment of the present invention, an air pocket 6 is provided at the center of the end of the duct surrounded by the annular outlet 3 of the duct. The cooling air that rebounds from the lower part of the glass molded body 5 is buffered by the pool portion 6 and excessive turbulence of the air is reduced, so that the inner surface deformation of the molded body due to the turbulence of the cooling air can be prevented. The pool 6 is formed by the inner pipe 2
It can be easily formed by shifting the mounting position of the closing top plate 7 upward.

The present invention is suitable for a case in which a plurality of dies are provided on a rotary disk in a multi-head manner and a glass molded body in the die is sequentially cooled at a plurality of positions while the rotary disk is rotated. This is because a desired cooling distribution can be more easily obtained by using in combination with a conventional duct. Therefore,
The method of the present invention may be applied to at least one of the plurality of cooling locations.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the molding of a 21-inch CRT panel using a rotating disk, the cooling method of the present invention was changed by changing the duct of the fifth cooling position among the six cooling positions to a duct having an annular outlet. did. The inner diameter of the outer tube was 200 mm, and the outer diameter of the inner tube was 130 mm. The cooling conditions at this time are summarized in Table 1 in comparison with the conventional method.

In the past, there was a problem in the mold release between the lower mold and the panel, and the inner and outer surfaces of the panel were greatly distorted in order to greatly increase the flow rate of the sixth cooling duct immediately before being taken out. Thus, even when the sixth cooling duct flow rate was reduced, the lower mold was released from the panel better, and the distortion of the inner and outer surfaces of the panel was reduced. as a result,
The turntable cycle time was reduced by 9%.

[0020]

[Table 1]

[0021]

According to the present invention, the cooling of the peripheral portion of the panel, which has been insufficient until now, can be effectively performed, and the temperature distribution of the panel can be optimized by the flow rate of the duct and the duct diameter. As a result, the mold release between the panel and the lower mold is improved, the distortion of the main surface of the panel is suppressed, and the production cycle time can be greatly improved. Further, since the conventional main facilities can be realized with only a part of additional changes as they are, new costs are minimized, so that the cost performance is excellent.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view schematically showing a cooling method of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a longitudinal sectional view of a duct used in another embodiment of the present invention.

[Explanation of symbols]

 1: Outer pipe 2: Inner pipe 3: Annular outlet 4: Lower die 5: Hollow glass molded body 6: Drift part

Claims (2)

[Claims] 1. A molten glass is supplied to a lower mold, and then the upper mold is lowered and press-molded, then the upper mold is raised to open the mold, and the hollow glass molded body in the lower mold has an annular outlet. A method for cooling a hollow glass molded body, comprising blowing air from a duct to cool the hollow glass molded body. 2. A duct according to claim 1, wherein said duct has a double pipe structure comprising an outer pipe and an inner pipe, and an air outlet is provided at a central portion of the end of the duct surrounded by an annular outlet. 1
A method for cooling a hollow glass molded body according to the above.