JPH06267512A - High power ultraviolet irradiation light source - Google Patents

Abstract

PURPOSE:To provide a high power luminous tube and improve its life property and ultraviolet output property by sending air into a space between the luminous tube of an ultraviolet irradiation lamp and the inner tube of a water cooling jacket for cooling. CONSTITUTION:A straight-run silica glass luminous tube 11 has both ends held via a steatite luminous tube base not to have contact with the inner tube 21 of a water cooling jacket 2. The jacket 2 has both ends fitted to disc-like end caps 3a, 3b, each of which is provided with a cool air vent hole 31 and an exhaust port 32. Cool air 5 from the outside flows from the vent hole 31 through the opening of the luminous tube base into a space between the luminous tube 11 and the inner tube 21 of the jacket 2, so that heat is dissipated from the surface of the luminous tube to be cooled down and exhausted from the exhaust port 32 to the outside. In this way, the luminous tube 11 is free from thermal deformation, devitrification with silica and reaction with additives and shows stable ultraviolet output property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a photochemical reaction light source used for drying ink or paint or curing a resin, and more particularly to a high power type UV irradiation light source.

[0002]

2. Description of the Related Art A light source used for drying UV-curable ink or paint is cooled with water to absorb heat rays in order to reduce the influence of heat radiated from the arc tube on a work. It is used as a formula. Also, drying,
There is a strong demand for increasing the curing speed and improving the curing performance of thick films, etc., and higher output of the light source is required.

In general, when a water-cooled lamp is used at a high output of 200 W / cm or more per effective luminous length of the arc tube, the cooling effect is not sufficient by indirectly cooling the outer circumference of the arc tube with cooling water. The surface temperature of the arc tube made of quartz glass exceeds 1000 ° C., and thermal deformation such as sagging or bulging of the quartz tube occurs. When a part of the arc tube comes close to the water cooling jacket due to thermal deformation of the arc tube, it becomes the coldest part, and the mercury or metal halide enclosed in the arc tube agglomerates, causing a rapid decrease in the ultraviolet ray output.

Further, when the surface temperature of the arc tube exceeds 1000 ° C., devitrification of the arc tube or a chemical reaction between quartz and the additive in the arc tube occurs, and the ultraviolet ray transmittance of the arc tube decreases, so that the ultraviolet ray output decreases. There is a problem.

[0005]

Therefore, it is conceivable to increase the tube diameter of the arc tube to lighten the load on the tube wall to lower the surface temperature of the arc tube. However, there is a problem in that the size of the ultraviolet irradiation device becomes large, and in particular, a reflector having the same size as that of the conventional one has a reduced light condensing degree and a peak illuminance of ultraviolet rays, which does not lead to improvement in performance as a high-output type light source.

The present invention has been made in view of the above circumstances, and it is possible to increase the output of an arc tube, and in particular, to obtain a high output type ultraviolet irradiation light source with a load per unit emission length of 200 W / cm or more. An object of the present invention is to provide a light source having excellent lamp characteristics such as life characteristics and ultraviolet ray output characteristics.

[0007]

DISCLOSURE OF THE INVENTION According to the present invention, a UV irradiation lamp is arranged in a double tube type water cooling jacket consisting of an inner tube and an outer tube, and the space between the arc tube of the lamp and the inner tube of the water cooling jacket. It is characterized by cooling by ventilating. In particular, it is characterized in that end caps are fitted to both ends of the double-tube water-cooling jacket, and cooling air is circulated from the outside to the exhaust port of the other cap through the ventilation port of the one cap.

[0008]

With the above structure, the ultraviolet irradiation lamp is cooled by the cooling water circulating through the water cooling jacket and the cold air flowing through the space between the arc tube and the water cooling jacket, so that the surface temperature of the arc tube is lowered. Further, thermal deformation of the arc tube does not occur, and devitrification of the quartz and reaction with the additive do not occur, so that stable UV output characteristics can be obtained.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view of an ultraviolet irradiation light source, which includes an ultraviolet irradiation lamp 1, a water cooling jacket 2, and end caps 3a and 3b at both ends of the water cooling jacket. The ultraviolet irradiation lamp 1 has a straight tube-shaped quartz glass arc tube 11 having a pair of electrodes sealed at both ends thereof, and a rare gas, mercury, and F.
At least one or more of metal halides such as e, Sn, Co, Mg, and Pb capable of obtaining effective light emission in the ultraviolet region are encapsulated. The water cooling jacket 2 is made of a transparent material such as cylindrical quartz glass and has a double pipe structure composed of an inner pipe 21 and an outer pipe 22. Also, the water cooling jacket 2 is connected to the outside through connecting pipes 23a and 23b provided on both outer circumferences. The cooling water 4 circulates in the jacket to cool the arc tube adjacent thereto through the air layer and absorb the heat radiated from the lamp 1.

As shown in FIGS. 1 and 2, both ends of the arc tube 11 are held so as not to come into contact with the inner tube 21 of the water cooling jacket through the arc tube base 12 made of steatite. In addition, an appropriate number of openings 13 are formed along the outer periphery of the flange portion of the base 12 to serve as cold air circulation holes. Further, disk-shaped end caps 3a and 3b are fitted at both ends of the water cooling jacket 2, one end cap 3a is provided with a cooling air vent 31 and the other end cap 3b is provided with an exhaust port 32. is there. Then, the cooling air 5 from the outside enters the inside of the water cooling jacket 2 from the ventilation hole 31 as shown by the arrow, passes through the opening 13 of the arc tube base 12, and the arc tube 1
1 and the inner tube 21 of the water cooling jacket 2 flow. At this time, heat is taken from the surface of the arc tube to cool the arc tube. Further, it is discharged to the outside from the opening 13 and the exhaust port 32 of the other arc tube base.

Next, specific examples of the present invention will be described. Approximately 10 Torr of rare gas, mercury, and halides of Fe and Sn are enclosed in a quartz arc tube with a total length of 530 mm, an outer diameter of 24 mm, and a distance between electrodes on both ends of 400 mm.
UV irradiation lamp, total length 550mm, outer tube inner diameter 36m
The lamp is supported via a Steatite arc tube base in which four openings with a diameter of 3 mm are formed in the flange inside a water-cooled jacket with an inner diameter of 26 mm, and end caps are fitted to both ends. A high power UV irradiation light source was constructed. Then, when the cooling water having a water temperature of 25 ° C. is circulated and used in the water cooling jacket and a required amount of air is ventilated from the outside to measure the arc tube surface temperature, the characteristics as shown in FIG. 3 are obtained. Was given.

As can be seen from the figure, the surface temperature of the arc tube 11 is about 1050 ° C. in the windless state when the lamp lighting load is 200 W / cm, but the surface temperature of the arc tube is 750 to 750 by flowing the cool air. It can be lowered to 900 ° C. Therefore, thermal deformation of the arc tube does not occur. It should be noted that the surface temperature of the arc tube is 1000 ° C., and it is desirable to regulate the surface temperature to 800 to 900 ° C. in consideration of the ultraviolet ray output intensity. As is clear from FIG.
It should be ~ 15 l / min.

In the above embodiment, the lamp load is 200 W / cm.
However, if it exceeds this, the surface temperature of the arc tube will be high, so it is necessary to increase the air volume.
On the contrary, when it is small, especially 160 W / cm is not a high power type light source, and it is not necessary to cool it by air.

As the air cooling means, cooling air may be blown or sucked to cool. Further, the arc tube base holds the lamp properly, and if the ventilation is possible, the shape or the number of openings can be freely designed.

[0015]

As is apparent from the above description, the high-power type UV irradiation light source according to the present invention enables high-speed photochemical reaction and high performance by using a high-load lamp. There are advantages such as excellent output characteristics.

[Brief description of drawings]

FIG. 1 is a schematic side view of a high-power type ultraviolet light source according to the present invention.

FIG. 2 is a side view and a plan view of the same main portion.

FIG. 3 is a characteristic diagram showing an arc tube surface temperature and a cooling air volume.

[Explanation of symbols]

 1 UV irradiation lamp 2 Water cooling jacket 21 Water cooling jacket inner pipe 22 Water cooling jacket outer pipe 23a, 23b Connection pipe 3a, 3b End cap 31 Vent port 32 Exhaust port 4 Cooling water 5 Cooling wind

Claims (2)

[Claims] 1. A light source in which an ultraviolet irradiation lamp is arranged in a double tube type water cooling jacket consisting of an inner tube and an outer tube, and is cooled by ventilating the space between the arc tube of the lamp and the inner tube of the water cooling jacket. A high-output type ultraviolet light source characterized by: 2. The end caps are fitted to both ends of the double-tube water-cooling jacket, and cooling air is circulated from the outside through the ventilation port of one cap to the exhaust port of the other cap. The high-power ultraviolet light source described.