JP4993666B2 - UV paint curing equipment, paint curing method - Google Patents

Description

  The present invention relates to an ultraviolet coating curing facility for irradiating a workpiece with ultraviolet rays and curing an ultraviolet curable coating applied to the surface of the workpiece, and a coating curing method by irradiating the workpiece with ultraviolet rays.

  Conventionally, an ultraviolet paint curing facility is used in a process of curing an ultraviolet curable paint (UV paint) applied to a workpiece such as a vehicle component. More specifically, in the ultraviolet paint curing equipment, the work surface is irradiated with ultraviolet rays while the work is conveyed in a certain direction by a conveyor, thereby curing the UV paint on the work surface.

  However, the oxygen present in the air may inhibit the curing of the UV paint (so-called “oxygen inhibition”). In conventional UV paint curing equipment, UV paint is cured by irradiating with a high amount of UV light so as to counteract the above oxygen inhibition. However, in order to cure UV paint efficiently, UV light is irradiated. It is desirable to reduce the oxygen concentration in the irradiation zone as much as possible.

Therefore, a processing tank having a work inlet / outlet formed at the top is provided, and ultraviolet rays are irradiated to the work passing through the processing tank in a state where the processing tank is filled with an inert gas such as carbon dioxide (carbon dioxide). (For example, refer to Patent Documents 1 and 2). In this way, as carbon dioxide heavier than air accumulates in the processing tank, the oxygen concentration in the processing tank decreases as air is pushed out from the work inlet / outlet, so the UV paint can be cured efficiently. Can do.
Japanese translation of PCT publication No. 2003-515445 (refer to claims 1, 5, 6 etc.) Japanese Patent Laying-Open No. 2005-342549 (see FIG. 1 etc.)

  By the way, a UV lamp is usually used for ultraviolet irradiation. Note that the UV lamp emits visible light and infrared light in addition to ultraviolet light. And the infrared rays irradiated from the UV lamp increase the temperature of the wall part of the processing tank by hitting the inner surface of the processing tank, and the heat of the wall part increases the temperature of carbon dioxide in the processing tank. In particular, if the workpiece is a large component such as a vehicle component, it is necessary to provide UV lamps at multiple locations in the treatment tank to irradiate the entire surface of the workpiece with ultraviolet rays, so the temperature rise of the wall becomes significant. Further, the temperature rise of carbon dioxide gas becomes remarkable. As a result, the specific gravity of the carbon dioxide gas becomes smaller and lighter, so that the carbon dioxide gas easily leaks out of the treatment tank through the work entrance at the top of the tank. Therefore, in order to keep the oxygen concentration low, the carbon dioxide gas must be continuously supplied, so that the consumption amount of the carbon dioxide gas increases, resulting in an increase in cost.

  This invention is made | formed in view of said subject, The objective is to provide the ultraviolet-ray coating curing equipment and coating-curing method which can suppress the consumption cost by reducing the consumption of an inert gas. .

In order to solve the above-mentioned problem, the invention described in claim 1 is an ultraviolet paint curing facility for irradiating a work piece with ultraviolet light to cure the ultraviolet curable paint applied to the work surface, and the inner surface side is light. It is composed of a wall portion that can function as a reflecting surface, and the wall portion has a pair of side walls provided perpendicular to the equipment installation surface and facing each other. A processing tank configured to accumulate heavy inert gas therein, and the work inlet / outlet while lifting the work while bringing the work into the processing tank via the work inlet / outlet while lowering the work to the carrying-out means for carrying out the work, through holes provided on at least one of the pair of side walls to the outside of the processing bath through the, so as not to protrude on the inner surface of the side wall Ri attached, a light source for irradiating ultraviolet light to the work passing through the processing bath, and a cooling means for cooling the side wall in a position facing the light source from its outer surface, said light source and said cooling means The gist of the present invention is an ultraviolet paint curing facility, which is arranged with the conveying means interposed therebetween .

  Usually, the wall portion located at the position facing the light source has a remarkable temperature rise because the light emitted from the light source directly hits it. However, according to the invention of claim 1, the wall portion is cooled by the cooling means. As a result, temperature rise is prevented. Thereby, since the temperature rise of the inert gas in a processing tank by the heat transmitted from the wall part can be prevented, the thermal expansion accompanying a temperature rise is avoided and the inert gas does not easily become light (that is, low density). As a result, the inert gas is less likely to leak out of the processing tank from the work inlet / outlet at the upper part of the tank, so that the consumption of the inert gas can be reduced, and consequently the running cost of the ultraviolet paint curing equipment can be suppressed. Further, since the inner surface side of the wall portion can function as a light reflecting surface, the ultraviolet rays uniformly strike the entire work surface while being reflected by the inner surface of the wall portion. Therefore, the ultraviolet curable coating material can be efficiently cured. Further, since the wall portion is cooled from the outer surface side by the cooling means, there is no need to install the cooling means on the inner surface side of the wall portion, and the light from the light source is not blocked.

  Here, examples of the inert gas include rare gas group element gases such as helium gas, neon gas, and argon gas in a narrow sense, and nitrogen gas and carbon dioxide gas having low chemical reactivity in a broad sense. Examples of the inert gas heavier than air include argon gas and carbon dioxide (carbon dioxide), but it is preferable to use carbon dioxide that is relatively cheaper than argon gas. Further, if carbon dioxide gas is used as the inert gas, the gas diffusion rate is lower than that of helium gas, nitrogen gas, or the like, so that the inert gas is less likely to leak out of the treatment tank.

In addition, examples of the cooling means include one that cools the wall portion using a refrigerant such as cold air or cooling water, but if the cold air is used as the refrigerant, the refrigerant flow path through which the refrigerant flows as much as the cooling water is used. Since it is not necessary to pay attention to the sealing, the cooling means can be easily configured.
Furthermore, in the present invention, the wall portion refers to a member that forms a processing tank, and is provided not only on the side wall provided perpendicular to the equipment installation surface (horizontal plane) but also on the equipment installation surface. Includes walls (upper and lower walls).

In order to solve the above-mentioned problems, the invention according to claim 2 is an ultraviolet paint curing facility for irradiating a work with ultraviolet light and curing the ultraviolet curable paint applied to the work surface, the inner surface side being light. It is composed of a wall portion that can function as a reflecting surface, and the wall portion has a pair of side walls provided perpendicular to the equipment installation surface and facing each other. A processing tank configured to accumulate heavy inert gas therein, and the work inlet / outlet while lifting the work while bringing the work into the processing tank via the work inlet / outlet while lowering the work with respect to the conveying means for unloading the workpiece, through holes provided on at least one of the pair of side walls to the outside of the processing bath through the, so as not to protrude on the inner surface of the side wall Ri attached, a light source for irradiating ultraviolet light to the work passing through the processing bath has a refrigerant flow path the light reflecting surface has and inside the outer surface, the side wall in a position facing the light source And a light reflecting member with a cooling mechanism installed in the light source, and the light source and the light reflecting member are disposed with the conveying means interposed therebetween, and the gist thereof is an ultraviolet paint curing facility.

  Usually, the wall portion at the position facing the light source has a remarkable temperature rise because the light emitted from the light source directly hits it. According to the invention of claim 2, the light reflecting member is provided on the wall portion. While installing, cooling a light reflection member with a cooling mechanism prevents the temperature of the wall from rising. Thereby, since the temperature rise of the inert gas in a processing tank by the heat transmitted from the wall part can be prevented, thermal expansion is avoided and the inert gas does not easily become light (that is, low density). As a result, the inert gas is less likely to leak out of the processing tank from the work inlet / outlet at the upper part of the tank, so that the consumption of the inert gas can be reduced, and consequently the running cost of the ultraviolet paint curing equipment can be suppressed. Further, since the inner surface side of the wall portion and the outer surface of the light reflecting member can function as a light reflecting surface, the ultraviolet rays uniformly hit the entire work surface while being reflected by these surfaces. Therefore, the ultraviolet curable coating material can be efficiently cured. The light reflecting member of the present invention may be installed, for example, on the inner surface side of a wall portion facing the light source, or may be installed so as to be fitted into an opening formed in the wall portion.

  Here, examples of the refrigerant that flows through the refrigerant flow path include cold air and cooling water. However, if cold air is used as the refrigerant, the cooling air flow may be reduced as much as when cooling water is used. Therefore, a light reflecting member with a cooling mechanism can be easily configured. Further, since the light reflecting member can be configured to be detachable, the light reflecting member can be replaced when it becomes dirty or damaged.

In order to solve the above-described problem, the invention according to claim 3 is configured such that the inner surface side is configured by a wall portion that can function as a light reflecting surface, and the wall portion is provided perpendicular to the equipment installation surface and faces each other. In a processing tank having a pair of side walls and having a work inlet / outlet formed in the upper part of the tank, an inert gas heavier than air is stored, and in this state, the work is carried in and out through the work inlet / outlet Irradiating the workpiece passing through the processing tank with ultraviolet light from a light source attached so as not to protrude to the inner surface side of the side wall with respect to a through hole provided in at least one of the pair of side walls , a coating curing method for curing the ultraviolet-curable coating material applied to the workpiece surface, using a cooling means placed on the side wall in a position facing the light source, to face the light source While cooling the side wall at the position from the outer surface side, and its gist the coating curing method characterized by performing the ultraviolet irradiation of the workpiece passing between said cooling means and said light source.

  Therefore, according to the third aspect of the present invention, since the ultraviolet ray is irradiated while cooling the wall portion facing the light source from the outer surface side, the temperature rise of the wall portion due to the light emitted from the light source is prevented. And the temperature rise of the inert gas in a processing tank by the heat transmitted from the wall part is prevented. As a result, the thermal expansion of the inert gas is avoided, the inert gas is not light (that is, has a low density), and the inert gas is less likely to leak out of the processing tank from the work entrance at the top of the tank. Therefore, the consumption of the inert gas can be reduced, and consequently the running cost of the ultraviolet paint curing equipment can be suppressed. In addition, since the work is carried in and out with the inert gas stored in the processing tank, the processing tank is filled with the inert gas when the work is irradiated with ultraviolet rays. Therefore, the ultraviolet curable coating is cured without being inhibited by oxygen.

In order to solve the above-described problem, the invention according to claim 4 is configured such that the inner surface side is configured by a wall portion that can function as a light reflecting surface, and the wall portion is provided perpendicular to the equipment installation surface and faces each other. In a processing tank having a pair of side walls and having a work inlet / outlet formed in the upper part of the tank, an inert gas heavier than air is stored, and in this state, the work is carried in and out through the work inlet / outlet Irradiating the workpiece passing through the processing tank with ultraviolet light from a light source attached so as not to protrude to the inner surface side of the side wall with respect to a through hole provided in at least one of the pair of side walls , a coating curing method for curing the ultraviolet-curable coating material applied to the workpiece surface, the flow of refrigerant to the light reflecting member with a cooling mechanism, wherein disposed on the side wall in a position facing the light source While cooling the light reflecting member itself Te, as its gist the coating curing method characterized by performing the ultraviolet irradiation of the workpiece passing between said light reflecting member and the light source.

  Therefore, according to the invention described in claim 4, since the ultraviolet light is irradiated while cooling the light reflecting member installed on the inner surface side of the wall portion at the position facing the light source, the light is emitted from the light source. The temperature rise of the wall portion is prevented, and the temperature rise of the inert gas in the treatment tank due to the heat transferred from the wall portion is prevented. As a result, the thermal expansion of the inert gas is avoided, the inert gas is not light (that is, has a low density), and the inert gas is less likely to leak out of the processing tank from the work entrance at the top of the tank. Therefore, the consumption of the inert gas can be reduced, and consequently the running cost of the ultraviolet paint curing equipment can be suppressed. In addition, since the work is carried in and out with the inert gas stored in the processing tank, the processing tank is filled with the inert gas when the work is irradiated with ultraviolet rays. Therefore, the ultraviolet curable coating is cured without being inhibited by oxygen.

  As described above in detail, according to the invention described in claims 1 to 4, it is possible to provide an ultraviolet paint curing facility and a paint curing method capable of reducing the consumption of the inert gas and suppressing the running cost. .

[First Embodiment]

  Hereinafter, a first embodiment embodying the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the ultraviolet paint curing equipment 10 is incorporated in a production line for producing a large workpiece W, and the workpiece W is irradiated with ultraviolet rays and applied to the workpiece surface in the previous step. This equipment cures mold paint (UV paint). The workpiece W of the present embodiment is a resin vehicle component (bumper) having a coated surface W1 on the front surface side and a concave curved surface W2 that is not the coated surface W1 on the back surface side.

  Further, the ultraviolet paint curing equipment 10 includes a work transfer passage 11 and a processing tank 12 positioned below the work transfer passage 11. The workpiece conveyance path 11 conveys the workpiece W to which the UV paint is applied. On the other hand, the processing tank 12 has a plurality of wall parts, specifically, a tank upper part 12a that constitutes a ceiling part of the processing tank 12, a tank bottom part 12b that constitutes a floor part of the processing tank 12, and four side walls 12e, 12f, 12g, and 12h are formed in a substantially rectangular parallelepiped shape. These tank upper part 12a, tank bottom part 12b, and side walls 12e to 12h are formed of an aluminum plate having gas impermeability in the thickness direction. The aluminum plate has a relatively high reflectivity of ultraviolet rays, and the inner surfaces of the tank upper part 12a, the tank bottom part 12b, and the side walls 12e to 12h are smooth surfaces. For this reason, the inner surface side of the tank upper part 12a, the tank bottom part 12b, and the side walls 12e to 12h functions as a light reflecting surface. Further, in the tank upper portion 12a, a work loading port 12c (work inlet / outlet) for loading the work W into the processing tank 12 from the work transfer path 11 and a work W outside the processing tank 12 (inside the work transfer path 11). A work carry-out port 12d (work entry / exit) for unloading is opened at different locations.

  As shown in FIGS. 1 and 2, the ultraviolet paint curing facility 10 includes a floor conveyor 14 as a conveying means. The floor conveyor 14 conveys the workpiece W with the concave curved surface W2 facing downward while being supported by the workpiece support 19. Further, the floor conveyor 14 carries the workpiece W into the processing tank 12 through the workpiece carry-in inlet 12c while lowering the workpiece W, and also moves outside the processing tank 12 through the workpiece carry-out outlet 12d while raising the workpiece W. The work W is carried out. In addition, the floor conveyor 14 is provided with the workpiece conveyance path | route 18 in which the workpiece | work support body 19 is conveyed. The workpiece conveyance path 18 is constituted by a pair of guide rails 17a having a U-shaped cross section. Both guide rails 17 a are provided in parallel to the longitudinal direction of the workpiece conveyance path 18.

  As shown in FIG. 2A, the work support 19 includes a carriage 17 on which four wheels 17c are rotatably attached. Each wheel 17c is supported by a pair of guide rails 17a. For this reason, the carriage 17 moves along the both guide rails 17a (work conveyance path 18) by being pulled by, for example, a pulling member (wire, chain, etc.) not shown. In addition, the structure which the trolley | bogie 17 self-propells may be sufficient. In addition, the work support 19 includes a support bar 17 b provided to be rotatable with respect to the carriage 17. The support bar 17b supports the workpiece W at the upper end portion and has a weight 17d heavier than the workpiece W at the lower end portion. Thereby, when the workpiece support 19 passes through the inclined portion of the workpiece conveyance path 18, the support rod 17b rotates with respect to the carriage 17 by the weight 17d. For this reason, the support bar 17b is maintained substantially upright with respect to the installation surface of the guide rail 17a, and the direction of the workpiece W supported by the support bar 17b is maintained in the substantially same state.

  As shown in FIGS. 1 and 2, UV lamps 61 a and 61 b (light sources) are respectively installed on the side walls 12 g and 12 h facing each other in the processing tank 12. Specifically, the UV lamp 61a is attached to the through hole 13 provided in the side wall 12g and protrudes to the outer surface side of the side wall 12g. Similarly, the UV lamp 61b is attached to the through hole 13 provided in the side wall 12h and protrudes to the outer surface side of the side wall 12h. Each of the UV lamps 61 a and 61 b is provided corresponding to a place where the lowest point of the floor conveyor 14 is present in the processing tank 12. These UV lamps 61a and 61b are installed in parallel to the height direction of the processing tank 12 (that is, vertically placed), and irradiate the work W passing through the processing tank 12 with ultraviolet rays. In addition, although each UV lamp 61a, 61b was installed vertically, it may be installed horizontally. If installed vertically as in this embodiment, the UV paint can be cured without unevenness.

  As the UV lamps 61a and 61b, as shown in FIG. 2, a condensing lamp including a light emitting unit 62 and an aluminum plate 63 (reflecting plate) having a concave reflecting surface is used. At the position where the UV lamps 61a and 61b and the processing tank 12 are partitioned, a heat ray cut filter 64 as a partition is provided. Specifically, the heat ray cut filter 64 is attached so as to close the through hole 13. The heat ray cut filter 64 transmits ultraviolet rays into the processing bath 12 among light rays (visible rays, ultraviolet rays, infrared rays) irradiated from the UV lamps 61 a and 61 b and suppresses transmission of infrared rays into the processing bath 12. It has become. Therefore, the UV lamps 61a and 61b are arranged close to the treatment tank 12 filled with carbon dioxide (carbon dioxide).

  As shown in FIGS. 1 and 2, cooling devices 41 a and 41 b (cooling means) are respectively installed on the side walls 12 g and 12 h facing each other in the treatment tank 12. More specifically, the cooling device 41a is installed on the side wall 12g facing the UV lamp 61b, and cools the side wall 12g. The cooling device 41b is installed on the side wall 12h facing the UV lamp 61a and cools the side wall 12h. That is, the cooling devices 41a and 41b and the UV lamps 61a and 61b are arranged in a staggered manner along the conveying direction of the workpiece W (see FIG. 2B). Each cooling device 41a, 41b is provided corresponding to a location where the lowest point of the floor conveyor 14 is present in the processing tank 12.

  As shown in FIG. 2A, the cooling devices 41a and 41b are arranged outside the processing tank 12, and include a box-shaped cooling device body 40, a plurality of cooling fins 42, and a fan 43. I have. The fan 43 is disposed on the lower side of the cooling device main body 40 and supplies outside air as cold air into the cooling device main body 40. The cooling fins 42 are arranged at equal intervals along the vertical direction on the outer surface of the side wall 12e located in the cooling device main body 40, and extend horizontally. Each cooling fin 42 is cooled by cold air sent from the fan 43. Thereby, the outer surfaces of the side walls 12g and 12h are cooled by the cooling devices 41a and 41b, and a part of the side walls 12g and 12h is cooled, and accordingly, the carbon dioxide gas in the processing tank 12 is also cooled. Further, the cold air that has passed through the cooling device main body 40 is discharged to the outside through the exhaust port 44. Note that the fan 43 of the present embodiment is disposed on the lower side of the cooling device main body 40 and allows cool air to flow from the lower side toward the upper side. You may make it flow cold air toward. In addition, the size and shape of the cooling device main body 40 may be arbitrarily changed according to the position of the fan 43.

  As shown in FIG. 1, the ultraviolet paint curing equipment 10 includes a tank 32 that stores carbon dioxide gas (inert gas) heavier than air in a liquefied state. Further, the ultraviolet paint curing equipment 10 includes a carbon dioxide supply pipe 37 that constitutes a carbon dioxide supply path capable of communicating between the tank 32 and the inside of the treatment tank 12. A heating device 34 and a decompressor 38 are installed on the carbon dioxide supply pipe 37. The heating device 34 heats the temperature of the carbon dioxide gas sent out from the tank 32 to, for example, 0 ° C. or higher and 10 ° C. or lower from below freezing point. Thereby, freezing of the decompressor 38 on the processing tank 12 side on the carbon dioxide supply pipe 37 can be prevented and temperature rise in the processing tank 12 due to the supplied carbon dioxide gas can be prevented. In addition, the heating apparatus 34 of this embodiment is an apparatus which uses a heat exchanger as a heating source. Moreover, the decompressor 38 is arrange | positioned downstream of the heating apparatus 34, and reduces the pressure of the carbon dioxide gas heated by the heating apparatus 34, and sends it to the process tank 12 side.

  As shown in FIG. 1, a carbon dioxide supply pump 33, a temperature sensor 39, a carbon dioxide supply valve 35 and a carbon dioxide supply port 36 are provided on the carbon dioxide supply pipe 37. The carbon dioxide gas supply pump 33 is disposed on the downstream side of the heating device 34, and the punching metal 51 is supplied with carbon dioxide gas heated by the heating device 34 at a speed of 10 mm / sec or less (in this embodiment, a speed of 2 mm / sec or less). (Rectifying means) is allowed to pass through. In this way, the speed of the carbon dioxide gas is suppressed, so that the carbon dioxide gas is less likely to leak out of the processing tank 12 from the work carry-in port 12c and the work carry-out port 12d. The temperature sensor 39 is disposed downstream of the carbon dioxide supply pump 33, measures the temperature of the carbon dioxide heated by the heating device 34, and outputs a first temperature measurement signal to the CPU 21. . The carbon dioxide supply valve 35 is disposed on the downstream side of the temperature sensor 39, and switches the carbon dioxide supply pipe 37 between an open state and a closed state. The carbon dioxide supply valve 35 is configured to be able to supply carbon dioxide into the treatment tank 12 when switched to the open state. Note that the carbon dioxide supply valve 35 of the present embodiment is an electromagnetic valve that is operated by a solenoid (not shown). Further, the carbon dioxide supply ports 36 are installed at a plurality of locations on the tank bottom 12b of the processing tank 12 (see FIG. 2A), and supply carbon dioxide into the processing tank 12. As a result, carbon dioxide gas accumulates in the treatment tank 12. Note that the carbon dioxide supply port 36 of the present embodiment is a nozzle that opens upward.

  As shown in FIGS. 1 and 2 (a), the punching metal 51 is parallel to the tank bottom 12b above the tank bottom 12b in the processing tank 12 and below the irradiation zone irradiated with ultraviolet rays. Has been placed. The punching metal 51 is configured by regularly arranging a plurality of through holes in a plate-like member. The punching metal 51 adjusts the flow of carbon dioxide when passing through each through-hole, and generates an upward flow of a minute wind velocity that flows upward from the entire tank bottom 12b. A filter or the like may be used instead of the punching metal 51 as the rectifying means. As the filter in this case, for example, a filter configured in a mat shape by stacking fibers together is suitable.

  As shown in FIG. 1, an oxygen concentration meter 24 and a thermometer 25 are installed in the irradiation zone in the treatment tank 12. The oxygen concentration meter 24 measures the oxygen concentration in the treatment tank 12 and outputs an oxygen concentration measurement signal to the CPU 21. Further, the thermometer 25 measures the temperature in the processing tank 12 and outputs a second temperature measurement signal to the CPU 21. The oxygen concentration meter 24 is located in the vicinity of the tank upper portion 12 a in the treatment tank 12 and is located above the upper end of the work W that has been conveyed to the lowest point of the floor conveyor 14. Accordingly, the oxygen concentration near the work W can be accurately measured by the oxygen concentration meter 24. Similarly, the thermometer 25 is also located in the vicinity of the tank upper portion 12a, and is located above the upper end of the work W that has been conveyed to the lowest point. Therefore, the temperature near the workpiece W can be accurately measured by the thermometer 25.

  Next, the electrical configuration of the ultraviolet paint curing equipment 10 will be described.

  As shown in FIG. 1, the ultraviolet paint curing facility 10 includes a control device 15 for comprehensively controlling the entire facility. The control device 15 includes a CPU 21, a ROM 22, a RAM 23, an input / output circuit, and the like. The CPU 21 is electrically connected to the UV lamps 61a and 61b, the floor conveyor 14, the fans 43 of the cooling devices 41a and 41b, the heating device 34, the decompressor 38, the carbon dioxide supply pump 33, and the carbon dioxide supply valve 35. They are controlled by various drive signals.

  Further, the first temperature measurement signal output from the temperature sensor 39 is input to the CPU 21. Then, the CPU 21 determines whether or not the temperature indicated by the first temperature measurement signal is lower than 0 ° C., and determines whether or not the temperature indicated by the first temperature measurement signal is higher than 10 ° C. ing. When the temperature indicated by the first temperature measurement signal is lower than 0 ° C., the CPU 21 performs control for starting heating of the carbon dioxide gas by the heating device 34. Further, when the temperature indicated by the first temperature measurement signal becomes higher than 10 ° C., the CPU 21 performs control to end the heating of the carbon dioxide gas by the heating device 34. According to such control, the temperature of the carbon dioxide gas supplied into the processing tank 12 can be kept constant. Moreover, since it is not necessary to heat the carbon dioxide gas wastefully, energy required for heating can be saved.

  Further, the oxygen concentration measurement signal output from the oxygen concentration meter 24 is input to the CPU 21. Then, the CPU 21 determines whether or not the oxygen concentration indicated by the oxygen concentration measurement signal is equal to or higher than a threshold value (for example, 3% or higher). When the oxygen concentration indicated by the oxygen concentration measurement signal is equal to or higher than the threshold value, the CPU 21 performs control to switch the carbon dioxide supply valve 35 to the open state. On the other hand, when the oxygen concentration indicated by the oxygen concentration measurement signal is less than the threshold value, the CPU 21 performs control to switch the carbon dioxide supply valve 35 to the closed state. According to such control, since the oxygen concentration in the treatment tank 12 can be kept constant, the coating quality is stabilized. Further, since the wasteful supply of carbon dioxide gas is reduced, the consumption amount of carbon dioxide gas can be further reduced.

  Further, the second temperature measurement signal output from the thermometer 25 is input to the CPU 21. Then, the CPU 21 determines whether or not the temperature indicated by the second temperature measurement signal is less than 20 ° C., for example, and determines whether or not the temperature indicated by the second temperature measurement signal is higher than 40 ° C. It has become. When the temperature indicated by the second temperature measurement signal is higher than 40 ° C., the CPU 21 starts cooling the carbon dioxide gas by the cooling devices 41a and 41b by increasing the rotation speed of the fan 43 and increasing the air flow. It comes to perform control. When the temperature indicated by the second temperature measurement signal is less than 20 ° C., the CPU 21 stops the cooling of the carbon dioxide gas by the cooling devices 41a and 41b by controlling the fan 43 to reduce the rotational speed by reducing the rotational speed. Control to do. According to such control, since the temperature in the processing tank 12 can be kept constant, the curing time of the UV paint becomes constant, and the coating quality is stabilized. Further, since it is not necessary to cool the carbon dioxide gas wastefully, energy required for cooling can be saved. Although the temperature threshold is 20 ° C. here, this value may be set at 20 ± 1 ° C.

  Next, a paint curing method using the ultraviolet paint curing equipment 10 will be described.

  First, the CPU 21 outputs drive signals to the heating device 34, the decompressor 38, the carbon dioxide supply pump 33, and the carbon dioxide supply valve 35. As a result, the carbon dioxide supply valve 35 is switched to the open state, and the carbon dioxide heated by the heating device 34 and decompressed by the decompressor 38 passes through the carbon dioxide supply pipe 37 by the carbon dioxide supply pump 33 and processed. The tank 12 is filled.

  In this state, the CPU 21 outputs a drive signal to the floor conveyor 14, causes the work support 19 (work W) to be carried into the processing tank 12 via the work carry-in entrance 12c, and performs processing via the work carry-out exit 12d. The work support 19 (work W) is carried out of the tank 12. The UV lamps 61a and 61b are always turned on because it takes time until the output of the ultraviolet rays is stabilized. For this reason, the workpiece | work W which passes the inside of the processing tank 12 is irradiated with an ultraviolet-ray. At this time, the ultraviolet rays uniformly strike the entire surface of the work W while being reflected by the inner surfaces of the tank upper part 12a, the tank upper part 12a, and the side walls 12e to 12h. As a result, the UV coating applied to the workpiece surface of the workpiece W is efficiently cured.

  By the way, although the carbon dioxide gas filled in the processing tank 12 accumulates in the processing tank 12, when the temperature of the side walls 12g and 12h rises when the light irradiated from the UV lamps 61a and 61b rises on the side walls 12g and 12h, the side wall 12g , 12h heats up. As a result, the specific gravity of the carbon dioxide gas decreases, flows upward, and leaks out of the processing tank 12 from the workpiece carry-in port 12c and the workpiece carry-out port 12d. For this reason, the CPU 21 always determines whether or not the temperature indicated by the second temperature measurement signal output from the thermometer 25 is higher than 40 ° C. When the temperature indicated by the second temperature measurement signal is higher than 40 ° C., the CPU 21 outputs a drive signal to the fan 43 of the cooling devices 41a and 41b, and controls to cool the side walls 12g and 12h from the outer surface. At this time, ultraviolet rays are irradiated to the workpiece W while the side walls 12g and 12h are cooled from the outer surface side. As a result, the carbon dioxide gas in the treatment tank 12 is also cooled, so that the specific gravity of the carbon dioxide gas increases, the specific gravity difference from the air increases, and the carbon dioxide gas becomes heavy. In this embodiment, when the specific gravity of carbon dioxide gas that becomes about 1.35 at 40 ° C. is cooled to 20 ° C., the specific gravity increases to about 1.43, and the difference from the specific gravity of air (about 1) increases. Thereafter, when the temperature indicated by the second temperature measurement signal becomes lower than 20 ° C., for example, the CPU 21 stops outputting the drive signal to the fans 43 of the cooling devices 41a and 41b.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) Normally, the side walls 12g and 12h located at the positions facing the UV lamps 61a and 61b are remarkably increased in temperature because the light irradiated from the UV lamps 61a and 61b directly hits them. Therefore, in the ultraviolet paint curing facility 10 of the present embodiment, the side walls 12g and 12h are cooled by the cooling devices 41a and 41b, so that the temperature rise of the side walls 12g and 12h can be prevented. Therefore, since the temperature rise of the carbon dioxide gas in the processing tank 12 due to the heat transmitted from the side walls 12g and 12h can be prevented, the thermal expansion of the carbon dioxide gas is avoided, and the carbon dioxide gas is difficult to be light (that is, low density). As a result, it is difficult for the carbon dioxide gas to leak out of the processing tank 12 from the work carry-in port 12c and the work carry-out port 12d, so that the consumption of the carbon dioxide gas can be reduced. For example, when the side walls 12g and 12h are cooled by the cooling devices 41a and 41b and the temperature (atmosphere temperature) in the processing tank 12 is cooled from 40 ° C. to 20 ° C., the amount of carbon dioxide outflow can be reduced by about 50%. Therefore, the running cost of the ultraviolet paint curing equipment 10 can be suppressed. Further, since the side walls 12g and 12h are cooled from the outer surface side by the cooling devices 41a and 41b, it is not necessary to install the cooling devices 41a and 41b on the inner surface side of the side walls 12g and 12h, and the light from the UV lamps 61a and 61b. Is not blocked. Moreover, since the space in the processing tank 12 is not reduced by the installation of the cooling devices 41a and 41b, problems such as contact between the workpiece W and the cooling devices 41a and 41b can be solved.

  (2) Since the treatment tank 12 of this embodiment is composed of an aluminum plate having a relatively high ultraviolet reflectance, the ultraviolet light is reflected by the tank upper part 12a, the tank upper part 12a, the inner surfaces of the side walls 12e to 12h, and the like. However, it hits the entire surface of the work W evenly. Therefore, even if the number of UV lamps 61a and 61b is reduced or the amount of light is reduced, the UV paint can be cured efficiently. Moreover, since the processing tank 12 is comprised by the aluminum plate which has a gas impermeability with respect to the thickness direction, a carbon dioxide gas permeate | transmits the tank upper part 12a, the tank bottom part 12b, and the side walls 12e-12h, and the processing tank 12 There is no leakage outside. Furthermore, since the work carry-in port 12c and the work carry-out port 12d are formed in the tank bottom 12b, the leakage of carbon dioxide from the work carry-in port 12c and the work carry-out port 12d can be minimized. Accordingly, it is possible to form the workpiece carry-in port 12c and the workpiece carry-out port 12d to some extent, and it is possible to process a large workpiece W having a three-dimensional shape.

  (3) In this embodiment, since carbon dioxide gas is supplied from the tank bottom 12b far from the work carry-in port 12c and the work carry-out port 12d, the carbon dioxide gas is difficult to diffuse into the air. And since the punching metal 51 produces an upward flow, the carbon dioxide gas which tends to flow to the tank bottom part 12b side can be reached to the tank upper part 12a. Therefore, the inside of the processing tank 12 can be reliably filled with carbon dioxide gas. Furthermore, it is possible to prevent the air outside the processing tank 12 from entering through the work carry-in port 12c and the work carry-out port 12d by the wind pressure of the upward flow.

(4) In the coating material curing method of the present embodiment, the work W is loaded after the carbon dioxide gas is accumulated, instead of storing the carbon dioxide gas in the processing tank 12 after the work W is loaded. Therefore, it is not necessary to stop the floor conveyor 14 in a state where the workpiece W is loaded and wait for the carbon dioxide gas to accumulate during the irradiation of ultraviolet rays. Therefore, the curing operation of the UV paint can be performed efficiently.
[Second Embodiment]

  Next, the ultraviolet paint curing facility 10 of the second embodiment will be described. In addition, about the structure which is common in 1st Embodiment, the detailed description is abbreviate | omitted instead of attaching | subjecting the same member number.

  As shown in FIG. 3, the ultraviolet paint curing equipment 10 of the present embodiment has a light with a cooling mechanism on the inner surface side of the side wall 12 h (or the side wall 12 g) at a position facing the UV lamp 61 a (or the UV lamp 61 b). The point which installed the reflection member 71 differs from 1st Embodiment. That is, the light reflecting member 71 is separate from the processing tank 12. The light reflecting member 71 has a flat plate shape and is disposed in contact with the side wall 12h (or the side wall 12g), so that contact with the workpiece W being conveyed is prevented.

  The light reflecting member 71 has substantially the same configuration as the cooling devices 41a and 41b of the first embodiment, and has a coolant channel 70 inside. On the coolant channel 70, a light reflecting member main body 72, a plurality of cooling fins 73, and a fan 43 are provided. The light reflecting member main body 72 is made of an aluminum plate having a relatively high ultraviolet reflectance, and the outer surface is a light reflecting surface. The light reflecting member main body 72 is itself cooled by cold air (refrigerant) sent from the fan 43 to each cooling fin 73. Along with this, the carbon dioxide gas in the treatment tank 12 is also cooled.

  Therefore, according to the present embodiment, the light reflecting member 71 is installed on the inner surface side of the side wall 12h (or the side wall 12g), and the light reflecting member 71 is cooled, thereby increasing the temperature of the side wall 12h (or the side wall 12g). Is prevented. Thereby, since the temperature rise of the carbon dioxide gas in the processing tank 12 by the heat transmitted from the side wall 12h (or the side wall 12g) can be prevented, the thermal expansion of the carbon dioxide gas is avoided, and the carbon dioxide gas is light (that is, low density). Hard to become. As a result, the carbon dioxide gas is less likely to leak out of the processing tank 12 from the work carry-in port 12c and the work carry-out port 12d, so that the consumption amount of the carbon dioxide gas can be reduced, and consequently the running cost of the ultraviolet paint curing equipment 10 can be suppressed. .

  In addition, you may change each embodiment of this invention as follows.

  -The cooling devices 41a and 41b of the said embodiment were each installed in the side walls 12g and 12h which face each other in the processing tank 12. FIG. However, the cooling devices 41a and 41b may be arranged so as to surround the processing tank 12 from below. Specifically, as shown in FIG. 4, the cooling device 41 may be disposed so as to cover the side walls 12 g and 12 h and the tank bottom 12 b.

  As shown in FIG. 5, the UV lamps 61a and 61b may be arranged so as to face each other on the side walls 12g and 12h. And you may arrange | position the cooling devices 41a and 41b so that the UV lamps 61a and 61b may be enclosed.

  In the above embodiment, the side walls 12g and 12h are cooled by using the cooling devices 41a and 41b to cool the carbon dioxide gas in the treatment tank 12, but the carbon dioxide cooled by the cooling devices 41a and 41b is used. You may make it supply gas in the processing tank 12. FIG.

  -Although the refrigerant | coolant of the said embodiment was the cold wind sent out from the fan 43, it is good also considering a cooling water etc. as a refrigerant | coolant.

  -The tank upper part 12a of the said embodiment, the tank bottom part 12b, and the side walls 12e-12h were formed with the aluminum plate with a comparatively high ultraviolet reflectivity, and the inner surface side was able to function as a light reflection surface. However, the inner surface of the tank upper part 12a, the tank bottom part 12b, and the side walls 12e to 12h may be made to function as a light reflecting surface by polishing the inner surface to be a mirror surface or performing vapor deposition on the inner surface.

  In the above embodiment, the UV lamps 61a and 61b, the floor conveyor 14, the fans 43 of the cooling devices 41a and 41b, the heating device 34, the decompressor 38, the carbon dioxide supply pump 33, and the carbon dioxide supply valve 35 are controlled by one CPU 21. However, each control may be performed by separate CPUs.

  In the above embodiment, the bumper is exemplified as the workpiece W to be painted by the ultraviolet paint curing equipment 10, but the invention is not limited to this. For example, other vehicle parts such as an aerodynamic addition (such as a spoiler) may be used as the workpiece W. Further, the work W is not necessarily a vehicle component.

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiment described above are listed below.

  (1) The ultraviolet paint curing equipment according to claim 1, wherein the cooling means are arranged in a staggered manner along the conveying direction of the workpiece.

  (2) The ultraviolet paint curing facility according to claim 1, wherein the cooling means is disposed so as to surround the processing tank from below.

  (3) In Claim 1, the said light source is arrange | positioned so that it may mutually oppose in the said processing tank, The ultraviolet-ray paint hardening equipment characterized by the above-mentioned.

  (4) In the technical idea (3), the cooling means is disposed so as to surround the light source.

  (5) The ultraviolet paint curing facility according to claim 1 or 2, wherein the light source includes a heat ray cut filter at a position separating the light source and the processing tank.

  (6) The ultraviolet paint curing facility according to claim 1 or 2, wherein the light source is provided corresponding to a place where the lowest point of the conveying means is present in the processing tank.

  (7) In Claim 1 or 2, the workpiece entrance / exit is composed of a workpiece carry-in port for carrying the workpiece into the processing bath and a work carry-out port for carrying the workpiece out of the treatment bath. UV paint curing equipment characterized by that.

  (8) The ultraviolet paint curing facility according to claim 1 or 2, wherein the inert gas is carbon dioxide.

  (9) The ultraviolet paint curing method according to claim 1 or 2, wherein the inert gas is supplied so as to pass through the rectifying means at a speed of 10 mm / sec or less (preferably a speed of 2 mm / sec or less). Facility.

Sectional drawing which shows schematic structure of the ultraviolet-ray coating curing equipment in 1st Embodiment. (A) is a sectional side view showing a schematic configuration of an ultraviolet paint curing facility, and (b) is a plan view showing a schematic configuration of a treatment tank. The sectional side view which shows schematic structure of the ultraviolet-ray coating curing equipment in 2nd Embodiment. The sectional side view which shows schematic structure of the ultraviolet-ray coating curing equipment in other embodiment. The sectional side view which shows schematic structure of the ultraviolet-ray coating curing equipment in other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Ultraviolet paint hardening equipment 12 ... Processing tank 12a ... Tank upper part 12b as a wall part ... Tank bottom part 12c as a wall part ... Work inlet / outlet 12d as a work inlet / outlet Work outlets 12e, 12f, 12g as a workpiece inlet / outlet 12h ... side wall 14 as wall part ... floor conveyors 41a, 41b as conveying means ... cooling devices 61a, 61b as cooling means ... UV lamp 70 as light source ... refrigerant flow path 71 ... light reflecting member W with cooling mechanism ... work

Claims (4)

UV paint curing equipment that irradiates the work with UV light and cures the UV curable paint applied to the work surface.
The inner surface side is constituted by a wall portion that can function as a light reflecting surface, the wall portion is provided perpendicular to the equipment installation surface and has a pair of side walls facing each other, and a work entrance is formed at the top of the tank, A treatment tank configured to accumulate an inert gas heavier than air; and
Unloading means for unloading the work to the outside of the processing tank through the work entrance while raising the work, while loading the work into the processing tank through the work entrance while lowering the work;
A light source that is attached to at least one of the pair of side walls so as not to protrude to the inner surface side of the side walls, and that irradiates the workpiece passing through the processing tank with ultraviolet rays,
Cooling means for cooling the side wall at a position facing the light source from the outer surface side thereof ,
The ultraviolet paint curing facility, wherein the light source and the cooling means are arranged with the conveying means interposed therebetween . UV paint curing equipment that irradiates the work with UV light and cures the UV curable paint applied to the work surface.
The inner surface side is constituted by a wall portion that can function as a light reflecting surface, the wall portion is provided perpendicular to the equipment installation surface and has a pair of side walls facing each other, and a work entrance is formed at the top of the tank, A treatment tank configured to accumulate an inert gas heavier than air; and
Conveying means for carrying the work into the processing tank through the work entrance while lowering the work, and carrying the work out of the processing tank through the work entrance while raising the work;
A light source that is attached to at least one of the pair of side walls so as not to protrude to the inner surface side of the side walls, and that irradiates the workpiece passing through the processing tank with ultraviolet rays,
A light reflecting member with a cooling mechanism installed on the side wall , which has a light reflecting surface on the outer surface and a coolant channel inside and has a position facing the light source ;
The ultraviolet paint curing facility , wherein the light source and the light reflecting member are arranged with the conveying means interposed therebetween . The inner surface side is configured by a wall portion that can function as a light reflecting surface, and the wall portion has a pair of side walls that are provided perpendicular to the equipment installation surface and face each other, and a work entrance is formed in the upper part of the tank. While accumulating an inert gas heavier than air in the treatment tank and carrying in and out the workpiece through the workpiece inlet / outlet in this state, with respect to the through hole provided in at least one of the pair of side walls A paint curing method that cures an ultraviolet curable coating applied to the surface of the workpiece by irradiating the workpiece passing through the processing tank with ultraviolet rays from a light source attached so as not to protrude to the inner surface side of the side wall. There,
Passing between the light source and the cooling means while cooling the side wall at the position facing the light source from the outer surface side by using the cooling means installed on the side wall facing the light source. A method of curing a paint, characterized by performing ultraviolet irradiation on the workpiece. The inner surface side is configured by a wall portion that can function as a light reflecting surface, and the wall portion has a pair of side walls that are provided perpendicular to the equipment installation surface and face each other, and a work entrance is formed in the upper part of the tank. While accumulating an inert gas heavier than air in the treatment tank and carrying in and out the workpiece through the workpiece inlet / outlet in this state, with respect to the through hole provided in at least one of the pair of side walls A paint curing method that cures an ultraviolet curable coating applied to the surface of the workpiece by irradiating the workpiece passing through the processing tank with ultraviolet rays from a light source attached so as not to protrude to the inner surface side of the side wall. There,
The coolant passes through between the light source and the light reflecting member while cooling the light reflecting member by flowing a coolant through the light reflecting member with a cooling mechanism installed on the side wall facing the light source. A paint curing method characterized by performing ultraviolet irradiation on a workpiece.

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