JP6376384B2 - Ultraviolet irradiation discharge tube - Google Patents

Description

  The present invention relates to a discharge tube for ultraviolet irradiation capable of irradiating ultraviolet rays for curing ultraviolet curable ink and the like.

Ultraviolet irradiation discharge tubes that can irradiate ultraviolet rays that cure ultraviolet curable inks are used in the field of coatings in addition to printing and painting.
The discharge tube for ultraviolet irradiation generates heat during ultraviolet irradiation and the tube surface temperature becomes extremely high. For this reason, the discharge tube is provided with cooling means using cold air or cold water to control the tube surface temperature. As an example, Patent Document 1 discloses a water-cooled high-pressure discharge lamp.

JP 2008-146962 A

  The main cause of heat generation is that visible light, infrared rays, etc. other than ultraviolet rays irradiated from the discharge tube touch the air and exhaust as heat. Further, the ultraviolet rays that can be irradiated by the discharge tube are about 20%, and the others are visible light, infrared rays, and the like, and energy loss occurs with respect to power consumption. For this reason, there is a demand for a discharge tube that can efficiently irradiate ultraviolet rays, such as increasing the irradiation rate of ultraviolet rays by reducing irradiation other than ultraviolet rays with respect to power consumption.

  SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to provide an ultraviolet irradiation discharge tube that reduces the heat generation of a discharge vessel and increases the irradiation efficiency of ultraviolet rays by outputting direct current generated in the tube. Yes.

  As a first means for solving the above-mentioned problems, the present invention comprises a discharge vessel filled with mercury and an inert gas, and a pair of electrodes are attached so as to face both ends of the discharge vessel to allow alternating current to flow. An ultraviolet ray irradiation discharge tube capable of irradiating ultraviolet rays, wherein the discharge vessel includes a pair of DC output terminals capable of outputting a direct current of the discharge vessel during ultraviolet ray irradiation. It is to provide.

  The present invention provides, as a second means for solving the above-mentioned problem, in the first means, wherein the DC output terminal is at the center of the pair of electrodes and in a direction orthogonal to a straight line connecting the pair of electrodes facing each other. It is another object of the present invention to provide a discharge tube for ultraviolet irradiation characterized by being attached so as to face each other.

  According to the present invention, as a third means for solving the above-mentioned problems, in the first or second means, the discharge vessel is provided with a spherical portion having a central cross section larger than the cross sections at both ends, and the DC output terminal Is to provide a discharge tube for ultraviolet irradiation, wherein the pair of electrodes are mounted on a vertical line passing through the center of the spherical portion when the pair of electrodes are arranged along the horizontal direction.

  According to the above configuration, since the DC output terminal is provided, the DC in the discharge vessel can be taken out. Thereby, generation | occurrence | production of visible light other than an ultraviolet-ray, infrared rays, etc. can be reduced, the heat_generation | fever resulting from this can reduce, and the irradiation efficiency of an ultraviolet-ray can be improved.

  According to the above configuration, since the direct current output terminal is attached at the position farthest from the electrode, direct current generated in the discharge vessel can be output from the direct current output terminal to the outside without escaping from the electrode.

  According to the above configuration, mercury accumulates around the DC output terminal attached below the spherical portion, and this terminal is easily charged with a positive charge, and the DC output terminal attached downward from the DC output terminal attached above. Electrons move toward, and direct current easily flows. In addition, since the DC output terminal is attached at a position farthest from the electrode, the DC generated in the discharge vessel can be efficiently output from the DC output terminal to the outside without coming out of the electrode.

It is a front view which shows the structure outline of the discharge tube for ultraviolet irradiation of this invention.

  Embodiments of an ultraviolet irradiation discharge tube according to the present invention will be described below in detail with reference to the accompanying drawings.

[Ultraviolet irradiation discharge tube 10]
FIG. 1 is a front view showing a schematic configuration of a discharge tube for ultraviolet irradiation according to the present invention. As shown in the drawing, the discharge tube 10 for ultraviolet irradiation of the present invention has a discharge vessel 20, an electrode 30, and a DC output terminal 40 as the main basic configuration.

[Discharge vessel 20]
The discharge vessel 20 is a substantially straight tubular (rod-shaped) quartz glass tube using quartz glass as a material. Mercury and an inert gas are sealed inside the discharge vessel 20. As an example of the inert gas of the present invention, argon, neon, krypton, xenon, or the like can be used. The inert gas is sealed in the discharge vessel 20 so as to have an appropriate pressure (as an example, 2.66 kPa).

[Electrode 30]
A pair of electrodes 30 are attached to both ends of the discharge vessel 20 along the axial direction so that the tips are opposed to each other. As an example of the material of the electrode 30, tungsten can be used. The electrode 30 is electrically connected to a terminal 34 that protrudes outward in the axial direction of the discharge vessel 20 through a metal foil 32 that is airtightly embedded at both ends of the discharge vessel 20. As the metal foil 32, molybdenum or the like can be used as an example of a material. An alternating current power source is connected to the electrode 30 of the present embodiment to flow alternating current.

[Spherical part 22]
The discharge vessel 20 is provided with a spherical portion 22 at the center that is the farthest from the pair of electrodes 30 at both ends. The spherical portion 22 is set to have a cross-sectional diameter larger than the cross-sectional diameters at both ends of the discharge vessel 20, and in this embodiment, the cross-sectional diameter is set to twice the cross-sectional diameter at both ends. The center of the spherical portion 22 is set to be located at the center of the discharge vessel 20 on the longitudinal axis of the discharge vessel 20.

[DC output terminal 40]
The DC output terminal 40 is attached to the spherical portion 22. The DC output terminal 40 is attached at a position farthest from the axis of the discharge vessel 20. The DC output terminal 40 is attached at a position that is orthogonal to the axis of the discharge vessel 20 and passes through the center of the spherical portion 22. In other words, the DC output terminals 40 are attached in a pair so that the tips are opposed to each other on a perpendicular line passing through the center of the spherical portion 22 when the pair of electrodes 30 are arranged in the horizontal direction. The DC output terminals 40 are a pair of terminals using tungsten as an example of a material. The DC output terminal 40 is a terminal that protrudes and extends outward in the axial direction of the quartz glass via a metal foil 42 hermetically embedded in a cylindrical quartz glass connected on a vertical line passing through the center of the spherical portion 22. 44 is electrically connected. As the metal foil 32, molybdenum or the like can be used as an example of a material. The DC output terminal 40 of the present embodiment is a terminal that can output a DC current generated inside the discharge vessel 20. A measuring instrument, a power storage device, and the like can be connected to the terminal 44.

[Action]
The operation of the discharge tube for ultraviolet irradiation according to the present invention having the above configuration will be described below.
It arrange | positions on a mounting base so that the axial direction (line which connects a pair of electrodes 30) of the discharge tube 10 for ultraviolet irradiation may become a horizontal direction, an alternating current power supply is connected to a pair of electrodes 30, and alternating current is sent. The DC output terminal 40 is connected to a wiring connected to a measuring instrument, a power storage device, etc. via a terminal 44.

  Inside the discharge vessel 20, electrons that have jumped out of the cathode of the electrode 30 are pulled toward the anode. At this time, the electrons collide with the mercury atoms and give energy to the mercury atoms. The mercury atoms are excited to emit energy as light (emit light), become ultraviolet light, visible light, and infrared light, and are irradiated from the discharge vessel 20.

  In addition, in the pair of DC output terminals 40 of the discharge vessel, mercury tends to accumulate due to gravity around the lower DC output terminal 40 and is easily charged with a positive charge. For this reason, electrons generated inside the discharge vessel 20 are pulled toward the lower DC output terminal 40, and electrons flow from the upper DC output terminal 40 toward the lower DC output terminal 40. Direct current can be detected by a direct current measuring instrument connected to the direct current output terminal 40. Furthermore, the direct current can be stored by the power storage device connected to the direct current output terminal 40. As a result, power consumption related to irradiation of visible light other than ultraviolet rays, infrared rays and the like can be stored by changing to direct current, and the irradiation efficiency of ultraviolet rays can be increased, and the heat generation of the discharge vessel 20 can be greatly reduced.

[Example]
Mercury was enclosed in 8.16% (6 μl) with respect to the volume ratio (48 cc) of the discharge vessel 20. When an AC voltage of 200 V is applied to the electrode 30 of the ultraviolet irradiation discharge tube 10, the electrode 30 has a voltage of 23 V, a current of 7.2 A, and a power consumption of 157 W. The tube surface temperature of the discharge vessel 20 was about 150 ° C.
Next, a measuring instrument (galvanometer) was connected to the DC output terminal 40, and the DC flowing through the DC output terminal 40 was measured. As a result, the DC voltage was 2.5 V, the current was 0.7 A, and the output was 1.75 W. The tube surface temperature of the discharge vessel 20 was 78 ° C. Thus, 10% of power generation was possible from the discharge vessel 20.

  The ultraviolet rays irradiated from the discharge tube for ultraviolet irradiation according to the present invention had a main wavelength of 254 nm, 365 nm, and 405 nm.

  The waveform of the direct current output from the discharge tube for ultraviolet irradiation of the present invention was a sine wave and a half-wave rectified rectangular pulsating flow.

  According to such a discharge tube for ultraviolet irradiation of the present invention, since the direct current output terminal is provided, the direct current in the discharge vessel can be taken out and generation of visible light, infrared light, etc. other than ultraviolet light can be reduced. And heat_generation | fever of a discharge container reduces and can improve the irradiation efficiency of an ultraviolet-ray. Further, by storing the direct current flowing to the direct current output terminal while irradiating ultraviolet rays from the discharge container, the power consumption of the discharge tube can be effectively utilized.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used industrially particularly for a discharge tube using an AC power source.

DESCRIPTION OF SYMBOLS 10 ......... Discharge tube for ultraviolet irradiation, 20 ......... Discharge vessel, 22 ......... Spherical part, 30 ......... Electrode, 32 ......... Metal foil, 34 ......... Terminal, 40 ......... DC output terminal 42 ......... Metal foil, 44 ......... Terminal.

Claims (3)

An ultraviolet irradiation discharge tube comprising a discharge vessel filled with mercury and an inert gas, capable of irradiating ultraviolet rays by flowing alternating current by attaching a pair of electrodes so as to face both ends of the discharge vessel,
The discharge vessel includes a pair of direct current output terminals capable of outputting a direct current of the discharge vessel when irradiated with ultraviolet rays.   2. The ultraviolet irradiation according to claim 1, wherein the DC output terminals are attached so as to be opposed to each other in a direction orthogonal to a straight line connecting the opposed electrodes at the center of the pair of electrodes. Discharge tube.   The discharge vessel is provided with a spherical portion whose center cross section is larger than the cross section at both ends, and the DC output terminal is on a perpendicular line passing through the center of the spherical portion when the pair of electrodes are arranged along the horizontal direction. The discharge tube for ultraviolet irradiation according to claim 1 or 2, wherein the discharge tube is attached.

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