JP2010257877A - UV irradiation equipment - Google Patents

Abstract

An object of the present invention is to suppress early devitrification and blackening in the case of high input power by limiting the distance between an ultraviolet lamp and a cooling unit that are affected by lamp temperature.
A pair of discharge electrodes 15a and 15b are arranged opposite to each other in an axial direction in an arc tube 14 having an airtight discharge space 13 made of ultraviolet transmissive quartz glass. An ultraviolet lamp 100 is configured by enclosing a sufficient amount of a noble gas, mercury, halogen, and a light emitting metal enclosure to maintain an arc discharge state in the discharge space 13, and emits ultraviolet light when it is turned on. Let The ultraviolet lamp 100 is accommodated in the inner tube 21 of the dual structure cooling unit 200 that circulates a coolant 24 for cooling the ultraviolet lamp 100 between the inner tube 21 and the outer tube 22 and transmits ultraviolet rays. The distance D [mm] between the ultraviolet lamp 100 and the inner tube 21 of the cooling unit 200 and the input power P [W / cm] of the ultraviolet lamp 100 satisfy the relationship of D ≦ −0.2P + 35.
[Selection] Figure 1

Description

  The present invention relates to an ultraviolet irradiation device used for photochemical treatment, photodisinfection, photowashing, and the like with ultraviolet rays irradiated from an ultraviolet lamp.

  In the conventional ultraviolet irradiation device, the surface of the ultraviolet irradiation lamp that irradiates ultraviolet rays becomes high temperature. Therefore, a cooling mechanism for preventing breakage is necessary, and generally a cooling method by air cooling is used. The air cooling method includes a direct method in which a gas is directly applied to a lamp for cooling, and an indirect method in which the gas around the transmission container is cooled by cooling the transmission container installed in the outer peripheral direction of the lamp with a liquid, thereby cooling the lamp. In particular, the latter method is used when the temperature rise of the irradiated object is suppressed or when there is a liquid that is the irradiated object in the lamp outer peripheral direction. (For example, Patent Document 1)

JP 2008-226806 A

  Although the technique of the above-mentioned patent document 1 can improve the processing capability for the irradiated object by increasing the lamp input power, the indirect method of cooling the lamp by cooling the gas around the lamp, Since the cooling capacity is limited, the input power is limited to 120 W / cm or less. In general, when the lamp surface temperature continues to be lit at 850 ° C. or higher, there is a problem that defects such as devitrification and blackening occur at an early stage.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ultraviolet irradiation device capable of extending the life even by lighting with high input power by limiting the distance between the ultraviolet lamp that has an influence on the lamp temperature and the cooling unit. .

  In order to solve the above-described problems, an ultraviolet irradiation device according to the present invention includes an arc tube provided with a discharge space having an airtight property made of an ultraviolet light transmissive material, and an arc tube in the axial direction of the arc tube. An ultraviolet lamp comprising: a pair of discharge electrodes arranged; and an enclosure composed of a rare gas, mercury, halogen, and a luminescent metal in an amount sufficient to maintain an arc discharge in the discharge space. A cooling unit that houses the ultraviolet lamp, circulates a cooling liquid for cooling the ultraviolet lamp between the inner tube and the outer tube, and transmits ultraviolet rays, and includes the ultraviolet lamp and the cooling unit. The distance D [mm] from the inner tube and the input power P [W / cm] of the ultraviolet lamp satisfy the relationship of D ≦ −0.2P + 35.

  According to the present invention, by limiting the distance between the ultraviolet lamp that has an influence on the lamp temperature and the cooling unit, it is possible to extend the life of the lamp even when it is turned on with a high input power of 120 W / cm or more.

It is a system structure figure for explaining one embodiment about the ultraviolet irradiation device of this invention. It is a block diagram for demonstrating the ultraviolet lamp used in FIG. It is the I-I 'sectional view taken on the line of FIG. It is explanatory drawing for demonstrating the relationship of the distance of an ultraviolet lamp and a cooling unit. It is explanatory drawing for demonstrating the relationship between input electric power and the distance between an ultraviolet lamp and a cooling unit. It is a system structure figure for demonstrating other embodiment regarding the ultraviolet irradiation device of this invention. It is a block diagram for demonstrating the ultraviolet lamp used in FIG. It is the II-II 'sectional view taken on the line of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  1 to 3 are diagrams for explaining an embodiment of the ultraviolet irradiation apparatus according to the present invention. FIG. 1 is a basic system structure diagram. FIG. 2 is a configuration diagram for explaining an ultraviolet lamp used in FIG. 3 is a cross-sectional view taken along the line II ′ of FIG.

  The ultraviolet irradiation device includes an ultraviolet lamp 100 and a cooling unit 200. The ultraviolet lamp 100 and the cooling unit 200 are positioned at predetermined intervals by spacers 12a and 12b attached to the sockets 11a and 11b of the ultraviolet lamp 100.

  As shown in FIG. 2, the ultraviolet lamp 100 is made of quartz glass having ultraviolet transparency, and electrodes 15 a and 15 b made of, for example, tungsten are disposed inside both ends in the longitudinal direction of the arc tube 14 that forms the discharge space 13. The The arc tube 14 is constituted by a single tube having an outer diameter φ of 27.5 mm, a wall thickness m of 1.5 mm, and a light emission length L of about 100 mm, for example.

  The electrodes 15a and 15b are welded to one end of the molybdenum foils 17a and 17b via the inner leads 16a and 16b, respectively. One end of an outer lead (not shown) is welded to the other end of the molybdenum foils 17a and 17b. The portions of the molybdenum foils 17a and 17b heat and seal the arc tube 14 from the inner leads 16a and 16b of the arc tube 14 to one end of the outer lead.

  The molybdenum foils 17a and 17b may be any material that has a thermal expansion coefficient close to that of quartz glass forming the arc tube 14, but molybdenum is used as a material suitable for this condition. The outer leads connected at one end to the molybdenum foils 17a and 17b, respectively, are insulated and sealed with power supply lead wires 19a and 19b electrically connected inside, for example, ceramic sockets 18a and 18b. Connected to the power circuit.

  In the arc tube 14, a sufficient amount of argon gas, which is a rare gas for maintaining arc discharge, is 1.3 kPa, and iron, tin, indium, bismuth, which are metals for emitting mercury and ultraviolet light, At least one of thallium and manganese and a halogen are enclosed.

  The cooling unit 200 is made of a transparent material that is transparent to ultraviolet rays, such as cylindrical quartz glass. The cooling unit 200 includes an inner tube 21 and an outer tube 22 provided outside thereof, and has a double tube structure. The ultraviolet lamp 100 is included in the inner tube 21.

  As shown in FIG. 3, the inner tube 21 of the cooling unit 200 has an inner diameter d1 of 32 mm and an outer diameter d2 of 36 mm, and the outer tube 22 has an inner diameter d3 of 66 mm and an outer diameter d4 of 70 mm, for example.

  In the cooling unit 200, a coolant 24 such as water is circulated from the outside through connection pipes 23a and 23b provided at outer peripheral ends. As shown in FIG. 1, the coolant 24 has a low temperature from the connecting pipe 23a, cools the ultraviolet lamp 100 from the connecting pipe 23b, and discharges the warmed water. The warmed water is cooled and input again from the connection pipe 23a.

A metal oxide film is deposited on the outer surface of the outer tube 22. This metal oxide is composed of at least one of TiO ₂ , CeO ₂ , ZnO ₂ , SnO ₂ , and ZrO ₂ . The metal oxide film is component-adjusted so as to absorb a wavelength component of 300 nm or less in the light emitted from the ultraviolet lamp 100.

  When the lamp length is 100 cm and a lamp power of 16 kW (160 W / cm) is supplied and ultraviolet rays are emitted from the ultraviolet lamp 100, the metal oxide film deposited on the outer surface of the outer tube 22 is 300 nm or less. Absorbs wavelength components. Accordingly, ultraviolet rays having a wavelength range of 300 to 430 nm effective for curing the resin are transmitted through the cooling unit 200 and irradiated onto an irradiation object such as an ultraviolet curable resin.

  At this time, the cooling unit 200 circulates the coolant 24 and controls so that the temperature of the arc tube 14 of the ultraviolet lamp 100 does not exceed 850 ° C. It is known that when the surface temperature of the arc tube 14 reaches 850 ° C. or more, a blackening phenomenon occurs due to the reaction between the sealed gas and quartz glass which is the material of the arc tube 14.

  Here, regarding the relationship between the distance D between the luminous tube 14 of the ultraviolet lamp 100 having the above-described configuration and the inner tube 21 of the cooling unit 200 having the above-described configuration, D [mm] and the lamp input power P [W / cm], FIG. This will be described with reference to FIG.

  In FIG. 4, when the five types of input power of 80, 120, 140, 160, and 170 W / cm are supplied to the ultraviolet lamp 100, the favorable arc tube 14 and the inner tube 21 of the cooling unit 200 at 850 ° C. or less. The distance D is shown. In FIG. 4, considering the adverse effect of contact between the ultraviolet lamp 100 and the cooling unit 200, data is an example in which 1 mm is the minimum value.

  At 80 W / cm, the surface temperature of the arc tube 14 does not exceed 850 ° C. in any of up to 15 mm shown in FIG. 4, which is favorable in terms of lamp life. However, in this case, there is a problem that the desired illuminance cannot be obtained because the input power is small.

  In addition, the distance is about 11 mm or less at 120 W / cm, the distance is about 6.5 mm or less at 140 W / cm, the distance is about 3 mm or less at 160 W / cm, and the distance is about 1.3 mm or less at 170 W / cm. When set, the lamp can be made to have a long life since the blackening phenomenon due to the reaction between the enclosed material and the arc tube 14 can be prevented while obtaining good illuminance at 850 ° C. or lower.

  FIG. 5 shows a characteristic in which the input power [W / cm] at this time and the distance between the good arc tube 14 and the inner tube 21 are plotted in D [mm] and connected by a straight line. As can be seen from FIG. 5, an approximate expression D = −0.2P + 35 is obtained from the relationship of the distance D to the input at which the lamp surface temperature is 850 ° C. From this, it was possible to control the lamp temperature to 850 ° C. or lower under the condition of D ≦ −0.2P + 35. However, the input power P (W / cm) is assumed to be 120 ≦ P ≦ 170.

  In this embodiment, when the input power is between 120 W / cm and 170 W / cm, the distance D [mm] between the arc tube 14 and the inner tube 21 is a condition that satisfies the approximate expression of D ≦ −0.2P + 35. Thus, the blackening phenomenon can be suppressed while the desired illuminance is obtained, and the life can be extended.

  6 to 8 are diagrams for explaining another embodiment of the ultraviolet irradiation apparatus according to the present invention. FIG. 6 is a basic system structure diagram, and FIG. 7 is a configuration diagram for explaining an ultraviolet lamp used in FIG. 8 is a cross-sectional view taken along the line II-II ′ of FIG. In addition, the same code | symbol is attached | subjected to the component same as above-described embodiment, and description here is abbreviate | omitted.

  In this embodiment, a protrusion 61 whose tip is a spire or rounded shape is integrally formed on the outer surface of the intermediate portion in the longitudinal direction of the arc tube 14 of the ultraviolet lamp 100.

  The protrusion 61 is distinguished from an exhaust pipe trace, which is also referred to as a chip for enclosing an inclusion such as a rare gas in the arc tube 14, and the height of the provided projection 61 from the outer peripheral surface of the arc tube 14 is the exhaust gas. It is higher than the tube mark. The exhaust tube trace is not necessarily required by using the portion sealed by the arc tube 14, and can be eliminated.

  The height H of the protrusion 61 is such that the distance D [mm] between the arc tube 14 and the inner tube 21 satisfies the approximate expression of D ≦ −0.2P + 35 when the input power is between 120 W / cm and 170 W / cm. The relationship is lower (H <D) than the value. Under this condition, the value of the height of the protrusion 61 is determined as appropriate in consideration of the relationship between the input power values and the illuminance desired to be obtained with the same input power.

  In this embodiment, a protrusion lower than the distance D between the arc tube of the ultraviolet lamp and the inner tube of the cooling unit is integrally formed near the middle in the longitudinal direction of the arc tube. Thereby, long life can be ensured within the distance D. In addition to this, the middle part of the elongated arc tube in the longitudinal direction bends due to changes over time due to its own weight, thermal stress, etc. and directly touches the cooling unit, mercury in the lamp gathers at the contact part and the vapor pressure decreases. This also contributes to preventing the lamp voltage from decreasing.

  In this embodiment, at least one protrusion 61 may be formed on the outer peripheral surface of the arc tube 14, but a plurality of protrusions 61 may be formed in the peripheral surface direction as shown in FIG. In this case, as shown in FIG. 8, the position may not be on the same lap but may be shifted from the same lap. Furthermore, when the protrusions 61 are formed at a plurality of locations, they do not have to be on the same line in the axial direction.

100 UV lamp 13 Discharge space 14 Arc tube 15a, 15b Electrode 200 Cooling unit 21 Inner tube 22 Outer tube 24 Coolant 61 Projection

Claims (6)

An arc tube with a discharge space having an airtightness made of an ultraviolet light transmissive material;
A pair of discharge electrodes disposed opposite the arc tube in the axial direction of the arc tube;
An ultraviolet lamp comprising an enclosure made of a rare gas, mercury, halogen, and luminescent metal in a sufficient amount to maintain an arc discharge in the discharge space;
A cooling unit that houses the ultraviolet lamp, circulates a cooling liquid that cools the ultraviolet lamp between the inner tube and the outer tube, and transmits ultraviolet rays; and
The distance D [mm] between the ultraviolet lamp and the inner tube of the cooling unit and the input power P [W / cm] of the ultraviolet lamp satisfy the relationship of D ≦ −0.2P + 35. apparatus.   The ultraviolet irradiation apparatus according to claim 1, wherein the lamp input power P [W / cm] is in a range of 120 W / cm to 170 W / cm.   3. The ultraviolet irradiation apparatus according to claim 1, wherein a protrusion having a height lower than the distance D is integrally formed on the outer surface of the middle portion in the longitudinal direction of the arc tube.   4. The ultraviolet irradiation device according to claim 3, wherein at least one projection is provided on the outer surface in the longitudinal direction of the arc tube.   5. The ultraviolet irradiation device according to claim 3, wherein the protrusion has a thicker side on the arc tube side and a thinner tip.   The ultraviolet irradiation device according to claim 3, wherein the tip of the protrusion has a spire or a round shape.

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