JPH0216975Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to a heating furnace for manufacturing annular fluorescent lamps, and more specifically relates to a heating furnace used in the pretreatment process of straight bulb bending.

(b) Prior Art The process of heating and bending a straight bulb in the manufacture of annular fluorescent lamps is generally carried out in the following order using a turntable 1 as shown in FIGS. 1 to 6. The turntable 1 is arranged horizontally, has a plurality of heads 2, 2, . When a pair of heads 2,2 is in the first position _P1 , two straight valves 3,3 are supplied. These two straight bulbs 3, 3 have a fluorescent film formed on their inner surfaces, a stem having electrodes at both ends is sealed, and exhaust pipes 4, 4 extending from the upper end are connected to the corresponding heads 2, 2. At the same time, the two straight valves 3, 3 are suspended vertically at regular intervals by gripping the concave portion on the outer periphery of the upper end with the chucks 5, 5, and the two straight valves 3, 3 are suspended vertically at a constant interval, and the two straight valves 3, 3 are suspended in each subsequent position as a set.
It is intermittently fed to P ₂ , P ₃ . For example, if the radius r of turntable 1 is 1850 mm and the number of heads is 24,
The arrangement pitch ₁ of the two straight valves 3, 3 is set to approximately 180 mm, and these two are in the third position.
It is heated in the heating furnace 6 arranged at the ninth position _P3 to _P9 , and is bent into an annular shape at the tenth position _P10 . In this way, simultaneous heating and simultaneous bending of the straight valves 3, 3 as a set improves mass production.
This is effective as an energy saving measure, and the two array pitches ₁ of 180 mm are the most efficient heating size.

In the heating furnace 6 disposed at the third to ninth positions P ₃ to _{P 9} , a total of four heating sources are installed at each position (hereinafter referred to as heating positions P ₃ to _{P 9} ), for example, a radiant burner group 7, 7... will be installed.
One burner group 7 is a plurality of burners 8, 8... arranged in a continuous vertical line, and four burner groups 7a to 7a at any one heating position P _x are arranged in a row.
7d, the two burner groups 7a and 7b are fixed to the inner inner surface of the heating furnace 6, and the remaining two burner groups 7c and 7d are fixed to the outer inner surface of the heating furnace 6, as shown in FIG. Groups 7a and 7b and two outer burner groups 7c and 7d each facing each other 7a and 7
c, 7b and 7d are 2 at heating position P _x
7a, 3 and 7c and 7b, 3 and 7d are arranged in the radial direction of the turntable 1, being equidistant from the straight valves 3 and 3 and facing in parallel. These two straight valves 3, 3 have both burner groups 7a facing each other inside and outside.
and 7c, and are simultaneously heated by burner flames from 7b and 7d.

In the above manner, when the pair of straight valves 3, 3 enter the heating furnace 6, they are heated starting from the third heating position _P3 , and the temperature gradually rises, and then the temperature rises to the eighth, ninth heating position _P8 , At P ₉ , it is heated almost to its softening point. Also, two mount pins 9, 9 are waiting below the ninth heating position _P9 , and this position
When the straight valves 3, 3 are sent to P ₉ , the mount pins 9, 9 rise and the upper ends of the straight valves 3, 3
The valves 3, 3 are positioned by fitting into the lower end of the valve. The mount pins 9, 9 are the 10th pins coming out of the heating furnace 6.
The valves 3, 3 move intermittently together with the valves 3, 3 while they are positioned at position P ₁₀ , and at the 10th position P ₁₀ , the curved rollers 10, 10 with a two-part structure are used to grip the lower ends of the valves 3, 3. When the recess is ticked, the mounting pins 9,9 separate from the valves 3,3 and return to the ninth heating position _P9 . When the bending rollers 10, ₁₀ at the 10th position P10 check the valves 3, 3, they rotate upwardly along the valves 3, 3 and bend the straight valves 3, 3 into an annular shape.

By the way, each heating position P ₃ ~ of the heating furnace 6
At P ₉ , the pair of straight valves 3, 3 have opposing burner groups 7a, 7c, 7b facing their center line.
and 7d, but the two valves 3 and 3
Because the pitch ₁ of the bulb is as small as 180 mm, the opposing surfaces of the two bulbs 3 and 3 are heated to a higher temperature than the opposite surface due to each other's radiant heat, and the two bulbs form a V-shape as shown by the chain lines in Figure 5. Sometimes it warped. Such warping gradually increases starting from the third heating position _P3 , and when it reaches the ninth heating position _P9 , the mount pins 9, 9 are fixed to the straight valves 3, 3 due to the warping of the straight valves 3, 3. As a result, the lower ends of the straight valves 3, 3 may be damaged, and the valve position cannot be controlled by the mount pins 9, 9, resulting in the inability to perform bending or defective bending at the 10th position _P10. This is one of the factors that reduces the yield of annular fluorescent lamps.

(c) Purpose of the invention The purpose of the invention is to provide a heating furnace for manufacturing annular fluorescent lamps that solves the above-mentioned problems.

(d) Structure of the invention The present invention is an improved arrangement of heating sources in a heating furnace that simultaneously heats a pair of vertically suspended straight valves at multiple heating positions. The center-to-center distance between two opposing heating sources of four heating sources arranged with two straight valves in the middle in some heating positions is a set of two straight valves. It is characterized in that the arrangement pitch is the same as that of the above heating position, and the arrangement pitch of a set of two straight valves is selected and set within the range of 110 to 140% at other heating positions. The selection of the heating source arrangement pitch at each heating position takes into consideration that the warping of the pair of straight valves is corrected at least at the final heating position or a heating position near it, where the position is regulated by a mount pin, etc. be done. Therefore, even if a set of two straight valves are heated to warp in the heating furnace, the warp is corrected before exiting the heating furnace, and the bending process immediately after exiting the heating furnace is always performed accurately.

(E) Embodiment Next, an embodiment to which the present invention is applied will be described with reference to FIGS. 7 to 9. The _{heating furnace 6' shown in FIG .}
Heat sources installed separately, e.g. burner groups 11, 1
For example, the array pitch of 1... is set to the 7th heating position.
P ₇ is the same as before and the remaining heating position P ₃
~ Change only P ₆ , P ₈ , and P ₉ as follows.

Now, one of the heating positions P ₃ to P ₆ and P ₈ excluding heating positions P ₇ and P ₉ is set as P _y , and the four burner groups of this heating position P _y are set as 11a.
~11d, as _shown in FIG _. 180mm), e.g. 240mm within the range of 110-140% of ₁
Set to . Also, the opposing burner groups 11a and 11
c, 11b and 11d are arranged in the radial direction of the turntable 1, and due to the relationship ₂ > ₁ , the straight valves 3,
3 is placed inside the opposing line between the opposing burner groups 11a and 11c, 11b and 11d.

Also, the burner groups ₁₁ , 11, _.
Set it to

Further, two opposing burner groups 1 of the burner groups 11, 11, . . . at the final heating position _P9
The distance between the centers of 1, 11, 11, 11 _{is 1} or ₂
You can set it to , but experimentally it is ₁ 〈 ₃ 〈 ₂ .
It is desirable to set it to approximately 220mm of ₃ .

According to the above structure, a set of two straight valves 3, 3
In the third to sixth heating positions _P3 to _P6 , the opposite surfaces of the opposing surfaces are mainly heated by the burner flame. Therefore, the sixth heating position P ₆ where the heating temperature increases
9, the two straight valves 3, 3 bend inward toward each other as shown by the chain lines in FIG. When this comes to the seventh heating position P ₇ , here the two straight bulbs 3 , 3 are heated to a higher temperature on their opposite sides, so that in the seventh heating position P ₇ the two straight bulbs 3 , 3 are heated to a higher temperature.
3 begins to deform outward, and as a result, the straight valves 3, 3 approach a straight state in which the warp has been corrected.
When the straight valve 3, 3 whose warp has been corrected comes to the ninth heating position P9, a mount pin ₉ ,
9 is inserted, and even if heating continues thereafter, there is no worry that the straight valves 3, 3 will warp due to the position regulation of the mount pins 9, 9, and they are sent to the 10th position P ₁₀ in a straight state to the desired position. Bending processing is performed. By correcting the warpage of the straight valves 3 and 3 at the seventh heating position P ₇ , the mount pin can be inserted later.
Bending processing is performed normally.

Note that the present invention is not limited to the above-mentioned embodiments; depending on the dimensions of the straight valve, the heating source arrangement pitch at each heating position of the heating furnace may be selected in three or more stages, or two straight valves may be removed. It is also possible to select the heating source arrangement pitch so that the warp is corrected by heating the material so that it warps inwards and then warps inward. Further, the heat source may be an electric heater other than a gas burner, or a combination of a gas burner and an electric heater.

In addition, the regulation range of 110 to 140% of the heating source array pitch at each heating position of the heating furnace is such that when it is less than 110%, it becomes difficult to correct the warpage of the two straight valves, and there is no difference from the conventional method. This is based on the reason that if it exceeds 140%, the heating efficiency of the bulb will decrease significantly, which is disadvantageous in terms of energy.

(f) Effects of the invention As explained above, according to the invention, even if a pair of straight valves warps during heating, this warping can be corrected in the subsequent heating position, and therefore the bending process after heating can be corrected. The rate of defective products during production is significantly reduced, and the yield rate of annular fluorescent lamp manufacturing can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of a turntable for manufacturing annular fluorescent lamps, FIGS. 2 and 3 are schematic plan views and front views of the conventional heating furnace in FIG.
The figure is a sectional view taken along the line A-A in Fig. 3, Fig. 5 is a sectional view taken along the line B-B in Fig. 4, Fig. 6 is a partially enlarged sectional view of Fig. 2, and Fig. 7 is a sectional view taken along the line A-A in Fig. 3. 8 and 9 are schematic plan views of the inside of the heating furnace showing one embodiment of the present invention.
FIG. 2 is a partially enlarged sectional view and a partially front view of the figure. 3... Straight valve, 6'... Heating furnace, 11,1
1a to 11d...Heating source, _P3 to _P9 ...Heating position, ₁ ...Valve arrangement pitch, ₂ , ₃ ...
...Center-to-center distance between heating sources.

Claims (1)

[Scope of utility model registration request] A total of four vertical heating systems, each consisting of two straight valves suspended vertically at regular intervals and facing each other in parallel, with each valve placed in the middle in a direction perpendicular to the conveyance direction in which the valves are arranged. In a heating furnace having a plurality of heating positions heated by a heating source, the center-to-center distance between two opposing heating sources in each heating position is set to the arrangement pitch of a set of two valves in some heating positions. A heating furnace for manufacturing annular fluorescent lamps, characterized in that the temperature is selected within the range of 110 to 140%.