JPS637830B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultraviolet irradiation device for curing an ultraviolet curable resin coating, which is an object to be irradiated with ultraviolet rays, applied to the surface of a thread-like or string-like object running at high speed. More specifically, the purpose is to cool the discharge tube, which is the source of ultraviolet radiation, in a good and effective manner.

In recent years, with regard to optical fibers, which have been rapidly developing, the coating materials for optical fibers have been changing from heat-drying types to ultraviolet curing types, with the aim of reducing manufacturing costs and increasing production speed.

The basic structure of the commercially available ultraviolet irradiation equipment developed for the purpose of curing the ultraviolet curable paint coated on the surface of the optical fiber is the first reflector in the form of an elliptical cylinder with a mirrored inner surface. A discharge tube (hereinafter simply referred to as a UV lamp) such as an air-cooled high-pressure mercury lamp or an air-cooled metal vapor discharge lamp is placed at the focal axis position of the ultraviolet ray source, and an ultraviolet radiation source is placed at the second focal axis position. The ultraviolet ray transmitting hollow tubes that form the passages for the irradiated object to pass through are arranged and fixed, but this ultraviolet irradiation device is not always used in a constant position. It is used for optical fibers that run horizontally, or for optical fibers that run vertically, and optical fibers that run inside hollow tubes.
In some cases, there is one lamp, and in other cases there are several or even dozens of lamps, so the output of the UV lamp may need to be changed and adjusted, so the heating state of the UV lamp is not necessarily constant. For this reason, not only was it not possible to always operate the UV lamp in a good condition, but the UV lamp had to be operated in an unreasonable condition, which shortened the life of the UV lamp.

The present invention was devised to eliminate the drawbacks and inconveniences of the conventional examples described above, and it is possible to adjust the degree of air cooling for the discharge tube as a source of ultraviolet light, that is, the UV lamp, from both ends of the UV lamp. It has been made possible.

An embodiment of the present invention will be described below with reference to the drawings.

The ultraviolet ray irradiation device according to the present invention includes a cylindrical box body 5 whose both ends are closed by end plates, an elliptical cylinder whose inner circumferential surface is mirror-finished, and a first focal point of the mirror-finished elliptical inner circumferential surface. A discharge tube, that is, a UV lamp 1, which is a source of ultraviolet light is placed near the axis A, and an ultraviolet transmitting hollow tube 2, which forms a path for the object to be irradiated with ultraviolet light, is placed and fixed near the second focal axis B. An elliptical cylindrical reflecting mirror 3 is installed inside the box 5, and air chambers 9 are formed at both ends of the box 5 with open end faces of the reflecting mirror 3. A pair of retaining plates 6 are provided between the box body 5 and the reflecting mirror 3 to form a passage chamber 9' between the cylindrical wall and the outer peripheral surface of the reflecting mirror 3, and the passage chamber 9' is formed. It consists of a cooling air intake opening 10 and an exhaust opening 11 formed in the cylindrical wall portion of the box body 5, and includes three reflecting mirrors near the UV lamp 1;
That is, a first gap 4 as a passage for cooling air is formed at a location where the ellipse and its long axis intersect, and at the same time, the three reflecting mirrors near the hollow tube 2, that is, the ellipse and its long axis intersect. A second gap 4' as a passage for cooling air is formed at the location, an air volume adjustment hole 7 whose opening area can be adjusted is formed in the holding plate 6, and the second gap 4' and the exhaust gas are The exhaust opening 11 is communicated with the exhaust duct 11' by an exhaust duct 11'.

In the illustrated embodiment, the reflecting mirror 3 has an elliptical cylinder,
It is constructed by dividing the body into two parts along a plane including its long axis, and arranging the two divided elliptical cylinder pieces facing each other with first and second gaps 4 and 4' formed between the divided end faces. has been done.

This reflecting mirror 3 has both elliptical cylindrical pieces fixed to both holding plates 6 in a fixed positional relationship, and is attached and fixed to the box body 5 by these holding plates 6.

Therefore, by fixing the reflecting mirror 3 to the box body 5 using both holding plates 6, an air chamber 9 is formed in the box body 5 at both ends thereof, with the end faces of the reflecting mirror 3 being open. A passage chamber 9' located between the outer circumferential surface of the reflecting mirror 3 and the cylindrical wall of the box body 5 is formed in the center.

In the front wall of the cylindrical wall of the box body 5, an exhaust opening 11 is formed in the center, and intake openings 10 with intake air filters attached are formed on both sides of the exhaust opening 11. Both intake openings 10 serve as openings to the outside of the passage chamber 9', while the exhaust opening 1
1 is configured to communicate only with the second gap 4' through an exhaust duct 11'.

In addition, an air volume adjustment hole 7 formed in the holding plate 6
has a structure in which the aperture area can be adjusted, but this aperture area adjusting means is not particularly limited, and in the case of the illustrated embodiment, the air volume adjustment hole 7 is A flat plate-shaped air volume adjustment shutter 8 of a size that can completely close the air volume adjustment hole 7 is rotatably attached to the air volume adjustment hole 7 with a pin, and the amount of wrap of this air volume adjustment shutter 8 with respect to the air volume adjustment hole 7 is adjusted. By the way,
The opening area of the air volume adjustment hole 7 is adjusted and changed.

In this way, an air intake opening 10 and an exhaust opening 11 communicating with the second gap 4' are formed in the cylindrical wall of the box 5 forming the passage chamber 9', and the holding plate 6 is provided with an air volume adjustment mechanism. Since the hole 7 is formed, the cooling air taken into the passage chamber 9' from both the intake openings 10 directly cools the UV lamp 1 through the first gap 4, and then directly flows into the passage chamber 9'. 2 through the gap 4' and the exhaust opening 11, and from the passage chamber 9' through the air volume adjustment hole 7 to the air chamber 9.
The end portion of the UV lamp 1 is cooled from the air chamber 9 and separated into a portion that is exhausted through the second gap 4' and the exhaust opening 11. Note that FIGS. 2 and 3 In the hollow tube 2
Rare gas purge block 1 attached to one end
2 is for supplying a rare gas to cool the hollow tube 2.

As described above, the ultraviolet irradiation device according to the present invention blows cooling air onto the UV lamp 1 from the first gap 4 formed along the UV lamp 1, so that the UV lamp 1 can be effectively heated. Can be cooled.

In addition, a box body 5 in which both ends of the UV lamp 1 are located
An air chamber 9 is formed at both ends of the reflecting mirror 3 in which the UV lamp 1 is arranged, and the end face of the reflecting mirror 3 is open.
The amount of cooling air flowing into the air chamber 9 can be freely changed by adjusting the opening area of the air volume adjustment hole 7, so that there is no difference in the degree of cooling at both ends of the UV lamp 1. You will be able to give.

For example, as shown in Figure 2, in the case of horizontal installation where the UV lamp 1 is placed in a horizontal position, the UV
Since the lamp 1 is heated uniformly over its entire length, the cooling operation for the UV lamp 1 can be uniformly performed over its entire length, and therefore both air volume adjustment holes 7 have their open areas adjusted equally. Just leave it there.

On the other hand, as shown in Figure 3, in the case of a vertical arrangement in which the UV lamp 1 is placed in an upright position, the entire UV lamp 1 is uniform due to thermal interference between each part. Since the upper part is heated to a higher temperature than the upper part, the air volume adjustment hole 7 formed in the lower retaining plate 6 is closed and the lower part is heated to a higher temperature. While cooling air is not supplied to the air chamber 9 of
By fully opening the air volume adjustment hole 7 formed in the upper holding plate 6 and adjusting it so that a sufficient amount of cooling air is supplied to the upper air chamber 9, the UV lamp 1, which tends to become hot, can be removed. This means that the upper half of the UV lamp 1 can be sufficiently cooled, and thereby the UV lamp 1 can be operated in good condition.

Note that it is necessary to efficiently and uniformly irradiate the object with ultraviolet rays from the UV lamp 1 to the object passing through the hollow tube 2 at high speed. When UV-curable resin paint is actually cured, UV
The arc tube diameter d of lamp 1 is larger than 12 mm, but 24
Good results could be obtained by setting the value smaller than mm.

If the arc tube diameter d of the UV lamp 1 is set to 12 mm or less, the efficiency of collecting the generated ultraviolet rays will increase, but on the other hand, the lifespan will be shortened due to devitrification of the quartz tube that is the arc tube of the UV lamp 1. To prevent this, the input power to the UV lamp 1 must be reduced and the cooling of the UV lamp 1 must be achieved considerably, which is not practical in operation.

On the other hand, if the arc tube diameter d of UV lamp 1 is set to 24 mm or more, the efficiency of collecting the generated ultraviolet rays will be poor.
For this reason, it was not possible to efficiently cure the ultraviolet curable paint that was the object to be irradiated.

Further, it was preferable that the emission length of the UV lamp 1 was 150 mm or more.

This is because if the emission length of the UV lamp 1 becomes 150 mm or less, it becomes impossible to obtain a continuous curing effect due to light ripples of the UV lamp 1 which is AC-lit.

As is clear from the above description, the ultraviolet irradiation device according to the present invention can uniformly cool the entire UV lamp regardless of the position of the UV lamp, and therefore can operate the UV lamp well. In addition, this makes it possible to efficiently irradiate the object with ultraviolet rays, and since the position of the UV lamp is not restricted, the device can be installed and used in a convenient installation position. It exhibits many excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a simplified diagram for explaining the basic configuration of the apparatus of the present invention. FIG. 2 is a partially cutaway overall perspective view showing an embodiment of the horizontally installed apparatus of the present invention in which a UV lamp is arranged in a horizontal position. FIG. 3 is a partially cutaway overall perspective view showing an embodiment of the present invention apparatus of a vertical installation type in which a UV lamp is arranged in an upright position. Explanation of symbols: 1; UV lamp; 2; hollow tube;
3; Reflector, 4, 4'; Gap, 5; Box body, 6; Holding plate, 7; Air volume adjustment hole, 8; Air volume adjustment shutter, 9; Air chamber, 9'; Passage chamber, 10; Intake opening Part, 11; Exhaust opening, 11'; Exhaust duct.

Claims (1)

[Claims] 1 A cylindrical box 5 with both ends closed, a discharge tube 1 as an ultraviolet generation source near a first focal axis A of the elliptical cylindrical inner peripheral surface with a mirror surface, and a second focal axis B. An elliptical cylindrical reflecting mirror 3 is installed in the box body 5 with UV-transmitting hollow tubes 2 that form passages for the ultraviolet irradiated object arranged and fixed in the vicinity, The box body 5 is designed to form air chambers 9 with open end faces of the reflector 3, and to form a passage chamber 9' between the cylindrical wall of the box body 5 and the outer peripheral surface of the reflector 3. and a pair of retaining plates 6 provided between the reflecting mirror 3 and the passage chamber 9'.
A cooling air intake opening 10 and an exhaust opening 11 formed in the cylindrical wall portion of the box body 5 forming the
A first gap 4 as a passage for cooling air is formed at three locations of the reflecting mirror near the discharge tube 1, and a second gap 4 is formed at three locations of the reflecting mirror near the hollow tube 2.
A gap 4' is formed, an air volume adjustment hole 7 whose opening area can be adjusted is opened in the holding plate 6, and the second gap 4' and the exhaust opening 11 are communicated with each other. Irradiation device.