Paint drying equipment

Abstract

Provided is drying equipment for painting, with which heat loss can be reduced and energy can be saved.　This drying equipment for painting comprises a drying chamber 2 in which an object to be coated is dried, a heating means that heats air, an air supply means that supplies air heated by the heating means to the drying chamber 2, an air recovery means that recovers air from the drying chamber 2, and a processing means that processes volatile substances contained in the air recovered by the air recovery means. The drying equipment for painting is characterized in that the heating means doubles as the processing means.

Description

[Technical field]

[0001] The present invention relates to a coating drying facility comprising a drying chamber for drying substrates, a heating means for heating air, an air supplying means for supplying air heated by the heating means to the drying chamber, an air recovery means for recovering air from the drying chamber, and a processing means for processing volatile substances contained in the air recovered by the air recovery means. [Background technology]

[0002] In paint drying equipment used to dry painted automobiles and their parts, the temperature inside the drying chamber is generally maintained at around 120°C to 180°C, and the painted object is passed through the drying chamber for around 30 minutes to bake and harden the paint film.

[0003] As a means of heating the air supplied to the drying chamber, indirect heating furnaces (indirect heating furnaces) are used rather than direct flame heating furnaces, because there is a risk that nitrogen oxides, in particular, contained in the burner combustion gas, may have a deleterious effect on the coating, and this tendency is particularly strong in the topcoat drying process.

[0004] In addition, since the baking and hardening process of the coating generates volatile organic compounds (VOCs) with bad odors, the coating drying equipment is equipped with a deodorizing furnace as a means for treating the volatile organic compounds. It is generally said that volatile organic compounds are oxidized and decomposed by heating at 750°C to 800°C or higher for about 0.8 seconds, and the treatment in the deodorizing furnace is carried out according to such standards.

[0005] A conventional paint drying facility is known, for example, as shown in the following Patent Document 1. In this paint drying facility, the above-mentioned indirect heating furnace and deodorizing furnace are provided independently. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-238199 A Summary of the Invention [Problem to be solved by the invention]

[0007] In conventional paint drying equipment, heat loss of about 10% to 15% of the burner combustion amount occurs in the indirect heating furnace. This is the exhaust heat loss of the burner combustion air in the indirect heating furnace.

[0008] In addition, in conventional paint drying equipment, outside air heated by the heat obtained from the exhaust heat recovery of the deodorizing furnace is generally introduced into the drying chamber to ventilate the drying chamber, and the ventilated air is oxidized in the deodorizing furnace and exhausted outside the equipment. The heat loss associated with the ventilation of the drying chamber and the exhaust from the deodorizing furnace accounts for approximately 20% to 30% of the heat consumption of the entire drying chamber.

[0009] That is, in conventional paint drying equipment, heat loss is likely to occur in the indirect heating furnace and the deodorizing furnace, and there is still room for improvement in terms of reducing heat loss and saving energy.

[0010] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a paint drying facility which has less heat loss and can save energy. [Means for solving the problem]

[0011] The coating drying equipment according to the present invention is characterized by having a drying chamber for drying the object to be coated, The drying apparatus includes a heat exchanger for heating the air recovered from the drying chamber, and a combustion chamber for combusting the air recovered from the drying chamber to decompose volatile substances. A heating means; Equipped with The heating means in Heated air but The drying chamber fart supply Will be In paint drying equipment, The system further includes a first heat recovery means for recovering heat from exhaust gas discharged from the combustion chamber, and a second heat recovery means for recovering heat from exhaust gas discharged from the first heat recovery means, and the air supplied from the drying chamber to the combustion chamber is supplied from the drying chamber to the first heat recovery means and is preheated by the first heat recovery means before being supplied to the combustion chamber. It is at the point.

[0012] According to this configuration, since the heating means also functions as the processing means, it is easier to reduce the degree of heat loss and energy saving compared to the conventional case in which the heating means and the processing means are provided separately. Furthermore, since there is no need to provide a separate processing means, the equipment cost can be reduced. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic configuration diagram of a first embodiment of a paint drying facility. [Diagram 2] FIG. 4 is a schematic configuration diagram of a second embodiment of a paint drying facility. [Diagram 3] FIG. 11 is a schematic configuration diagram of a third embodiment of a paint drying facility. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] An embodiment of a paint drying facility according to the present invention will be described with reference to the drawings. [First embodiment] (Paint drying equipment) As shown in Figure 1, the paint drying equipment 1 includes a drying chamber 2 for drying the object to be coated, a heating means for heating air, an air supplying means for supplying the air heated by the heating means to the drying chamber 2, an air recovery means for recovering air from the drying chamber 2, and a treatment means for treating volatile substances contained in the air recovered by the air recovery means.

[0025] In the drying chamber 2, the object to be coated, such as a painted automobile body or part, is transported by a transport device (not shown) and baked and dried with hot air (for example, at about 140° C.).

[0026] Within the drying chamber 2, there is provided a transport device (not shown) for transporting objects to be coated, such as automobile bodies and parts after painting, a blow-out header 20 that blows out hot air supplied from the combustion treatment furnace 3, and a suction header 21 that sucks in and recovers the air within the combustion treatment furnace 3.

[0027] The heating means includes an indirect heating type combustion treatment furnace 3 having a combustion burner 30, a combustion chamber 31, and a heat exchanger 32, a fuel amount adjustment mechanism that adjusts the amount of fuel supplied to the combustion burner 30, and a combustion air amount adjustment mechanism that adjusts the amount of air supplied to the combustion burner 30.

[0028] The air supply means includes an air supply duct 4 and an air supply fan B1. The air supply fan B1 is disposed in the air supply duct 4. The combustion treatment furnace 3 is connected to the blowing header 20 of the drying chamber 2 via the air supply duct 4.

[0029] The air recovery means includes an air recovery duct 5. The combustion treatment furnace 3 is connected to the suction header 21 of the drying chamber 2 via the air recovery duct 5.

[0030] The paint drying equipment 1 further includes a first heat exchanger H1 as a first heat recovery means for recovering heat from the exhaust gas discharged from the combustion treatment furnace 3, a second heat exchanger H2 as a second heat recovery means for recovering heat from the exhaust gas discharged from the first heat exchanger H1, and an outside air introduction means for introducing outside air into the drying chamber 2.

[0031] The first heat exchanger H1 is connected to the combustion treatment furnace 3 via a first exhaust duct 7a. The second heat exchanger H2 is connected to the first heat exchanger H1 via a second exhaust duct 7b. The second heat exchanger H2 is provided with a third exhaust duct 7c for exhausting exhaust gas outside the facility. An exhaust fan B4 is installed in the middle of the third exhaust duct 7c.

[0032] By operating the exhaust fan B4, the exhaust gas discharged from the combustion treatment furnace 3 passes through the first exhaust duct 7a, the first heat exchanger H1, the second exhaust duct 7b, the second heat exchanger H2, and the third exhaust duct 7c in that order, and is exhausted outside the apparatus.

[0033] The first combustion air supply duct 6a branches off from the air recovery duct 5 upstream of the combustion furnace 3, and is connected to the first heat exchanger H1.

[0034] The first heat exchanger H1 is connected to the combustion chamber 31 via a second combustion air supply duct 6b.

[0035] The outside air introduction means includes a first outside air introduction section 9a for introducing outside air, and an outside air introduction amount adjustment mechanism for adjusting the amount of outside air to be introduced.

[0036] The first outside air introduction portion 9a is connected to the second heat exchanger H2 via a first outside air introduction duct 8a. An outside air introduction fan B3 is provided in the first outside air introduction duct 8a.

[0037] The second outside air introduction portion 9b is connected to the combustion burner 30 via a third outside air introduction duct 8c. A burner blower B2 is provided in the middle of the third outside air introduction duct 8c.

[0038] The second heat exchanger H2 is connected to the air supply duct 4 via a second outside air introduction duct 8b.

[0039] By operating the air supply fan B1, the air in the drying chamber 2 is sucked in through the suction header 21 and transferred to the air recovery duct 5, and then a portion of the air is transferred to the combustion treatment furnace 3 for heat treatment. The heated air is transferred to the air supply duct 4 and supplied into the drying chamber 2 via the blow-out header 20. In other words, a hot air circulation path is formed between the drying chamber 2 and the combustion treatment furnace 3.

[0040] In addition, by operating the exhaust fan B4, the remaining air transferred to the air recovery duct 5 is transferred to the first heat exchanger H1 via the first combustion air supply duct 6a and preheated. The preheated air is transferred to the combustion chamber 31 via the second combustion air supply duct 6b.

[0041] By operating the burner blower B2, outside air is supplied to the combustion burner 30 via the second outside air introduction part 9b and the third outside air introduction duct 8c.

[0042] By operating the outside air introduction fan B3, outside air is transferred to the second heat exchanger H2 via the first outside air introduction section 9a and the first outside air introduction duct 8a and is preheated. The preheated outside air is transferred to the air supply duct 4 via the second outside air introduction duct 8b, and after merging with the air that has been heat-treated in the combustion treatment furnace 3, it is supplied into the drying chamber 2 via the blow-out header 20.

[0043] In this embodiment, the heating means is configured to also function as the processing means. That is, a part of the air containing the volatile substances in the drying chamber 2 is transferred to the combustion chamber 31 via the first combustion air supply duct 6a and the second combustion air supply duct 6b, and is maintained in the combustion chamber 31 at a high temperature where the volatile substances can be decomposed, whereby the volatile substances are oxidatively decomposed.

[0044] In this embodiment, the combustion air (a part of the air containing volatile substances in the drying chamber 2) advected through the first combustion air supply duct 6a is preheated in the first heat exchanger H1 to perform primary heat recovery. And the outside air introduced through the first outside air introduction part 9a is preheated in the second heat exchanger H2 to perform secondary heat recovery.

[0045] By performing this primary heat recovery and secondary heat recovery, it is possible to make the temperature of the exhaust gas discharged from the combustion treatment furnace 3 approximately the same as the temperature inside the drying chamber 2, thereby further reducing heat loss in the paint drying equipment 1.

[0046] According to this embodiment, since outside air is introduced into the combustion burner 30, clogging of the burner nozzle of the combustion burner 30 due to volatile substances in the combustion air does not occur, and redundancy is provided.

[0047] (Control method for coating drying equipment) The paint drying equipment 1 of this embodiment is provided with a drying chamber temperature sensor (not shown) for detecting the temperature inside the drying chamber 2, a combustion furnace temperature sensor T for detecting the temperature of the combustion exhaust gas of the combustion burner 30 inside the combustion treatment furnace 3, a flowmeter F1 for measuring the flow rate of air in the first combustion air supply duct 6a, a flowmeter F2 for measuring the flow rate of air in the first outside air introduction duct 8a, a fuel supply valve for supplying fuel to the combustion burner 30, and a controller. Note that a VOC concentration sensor for detecting the concentration of volatile organic compounds (VOCs) inside the drying chamber 2 may be provided as necessary.

[0048] The controller controls the opening of the fuel supply valve and the output of the burner blower B2, the outside air introduction fan B3, and the exhaust fan B4 based on the detection values ​​of the drying chamber temperature sensor, the combustion furnace temperature sensor T, the flow meter F1, the flow meter F2, etc.

[0049] The fuel amount adjustment mechanism that adjusts the amount of fuel supplied to the combustion burner 30 is configured with a controller and a fuel supply valve. The combustion air amount adjustment mechanism that adjusts the amount of air supplied to the combustion burner 30 is configured with a controller and a burner blower B2. The outside air introduction amount adjustment mechanism that adjusts the amount of outside air introduced is configured with a controller and an outside air introduction fan B3.

[0050] The temperature inside the drying chamber 2 can be maintained at a set temperature (for example, about 140°C) by the controller controlling the fuel supply valve and adjusting the amount of fuel supplied to the combustion burner 30. Even when the amount of fuel supplied is maximized, it is desirable to ensure an air ratio of 1.0 or more. The case where the amount of fuel is minimized refers to a state where the fuel supply valve is at the minimum opening, the amount of fuel is about 1 / 10 of the rated amount, and the amount of heat loss exceeds the amount of heat generated.

[0051] The controller also controls the burner blower B2 to supply air in proportion to the amount of fuel to achieve the set air ratio.

[0052] The controller controls the burner blower B2, so that the temperature inside the combustion furnace 3 can be maintained at a set temperature (e.g., 800°C to 1000°C). When the temperature inside the combustion furnace 3 exceeds the set upper limit, the airflow of the burner blower B2 is increased to adjust the temperature inside the combustion furnace 3 to below the upper limit, and when the temperature falls below the set lower limit, the airflow of the burner blower B2 is decreased to adjust the temperature inside the combustion furnace 3 to above the lower limit.

[0053] The controller controls the outside air introduction fan B3 to adjust the amount of outside air introduced, thereby maintaining the VOC concentration within a certain range in the drying chamber 2. Note that the VOC concentration (also referred to as the VOC load in this specification) may be determined based on the detection value by the VOC concentration sensor, or may be determined based on the number of objects to be coated present in the drying chamber 2, the control output of the combustion burner 30, or the like.

[0054] The controller is configured to be able to adjust the amount of exhaust by controlling the output of the exhaust fan B4 and the like based on the VOC load in the drying chamber 2.

[0055] In addition, it is preferable that the controller controls the burner blower B2 and the outside air introduction fan B3 so that the amount of combustion air and the amount of introduced outside air are approximately equal.

[0056] The amount of outside air introduced is adjusted by the controller and the outside air introduction fan B3 so that the flow rate of the first outside air introduction duct 8a is approximately the same as the amount of combustion air in the first combustion air supply duct 6a. For example, in this embodiment, the flow meter F1 provided in the first combustion air supply duct 6a and the flow meter F2 provided in the first outside air introduction duct 8a adjust the mass flow rate converted from the temperature of the passing air to be approximately the same. The reason why the flow meter F1 is provided in the first combustion air supply duct 6a is that the air volume of the third exhaust duct 7c includes the air volume from the burner blower B2, and the combustion air in the second combustion air supply duct 6b is heated by the first heat exchanger H1, which reduces the measurement accuracy.

[0057] Second Embodiment Next, a second embodiment of the paint drying equipment 1 according to the present invention will be described with reference to the drawings. Configurations similar to those in the first embodiment described above will be given the same symbols and will not be described again, and different configurations will be mainly described.

[0058] As shown in FIG. 2, the first heat exchanger H1 in the paint drying equipment 1 of this embodiment is connected to the combustion chamber 31 via the second combustion air supply duct 6b, and is further connected to the combustion burner 30 via the third combustion air supply duct 6c.

[0059] The third combustion air supply duct 6c branches off from the second combustion air supply duct 6b, and a burner blower B2 is installed midway through the third combustion air supply duct 6c.

[0060] By operating the air supply fan B1, the air in the drying chamber 2 is sucked in through the suction header 21 and transferred to the air recovery duct 5, and then a portion of the air is transferred to the combustion treatment furnace 3 for heat treatment. The heated air is transferred to the air supply duct 4 and supplied into the drying chamber 2 via the blow-out header 20. In other words, a hot air circulation path is formed between the drying chamber 2 and the combustion treatment furnace 3.

[0061] By operating the exhaust fan B4, the remaining air transferred to the air recovery duct 5 is transferred to the first heat exchanger H1 via the first combustion air supply duct 6a and preheated. The preheated air is transferred to the combustion chamber 31 via the second combustion air supply duct 6b.

[0062] Also, a part of the air preheated in the first heat exchanger H1 is supplied to the combustion burner 30 via the third combustion air supply duct 6c by operating the burner blower B2.

[0063] In this embodiment, the heating means is also configured to function as the processing means. That is, a part of the air containing the volatile substances in the drying chamber 2 is transferred to the combustion chamber 31 via the first combustion air supply duct 6a and the second combustion air supply duct 6b, and is supplied to the combustion burner 30 via the first combustion air supply duct 6a, the second combustion air supply duct 6b, and the third combustion air supply duct 6c, and is maintained in the combustion chamber 31 at a high temperature at which the volatile substances can be decomposed, whereby the volatile substances are oxidatively decomposed.

[0064] According to this embodiment, outside air is not used as the air supplied to the combustion burner 30, which results in a high energy saving effect, and since the combustion air is taken in in proportion to the amount of fuel, a stable flame can be generated.

[0065] In addition, in this embodiment, the amount of outside air introduced is adjusted by the controller and the outside air introduction fan B3 so that the flow rate of the first outside air introduction duct 8a is approximately the same as the amount of combustion air in the first combustion air supply duct 6a or the exhaust amount of the third exhaust duct 7c.

[0066] Third Embodiment Next, a third embodiment of the paint drying equipment 1 according to the present invention will be described with reference to the drawings. Configurations similar to those in the first embodiment described above will be given the same symbols and will not be described again, and different configurations will be mainly described.

[0067] As shown in Fig. 3, the first heat exchanger H1 in the paint drying equipment 1 of this embodiment is connected to the combustion burner 30 via the second combustion air supply duct 6b. A burner blower B2 is installed in the middle of the second combustion air supply duct 6b.

[0068] By operating the air supply fan B1, the air in the drying chamber 2 is sucked in through the suction header 21 and transferred to the air recovery duct 5, and then a portion of the air is transferred to the combustion treatment furnace 3 for heat treatment. The heated air is transferred to the air supply duct 4 and supplied into the drying chamber 2 via the blow-out header 20. In other words, a hot air circulation path is formed between the drying chamber 2 and the combustion treatment furnace 3.

[0069] By operating the burner blower B2, the remaining air transferred to the air recovery duct 5 is transferred to the first heat exchanger H1 via the first combustion air supply duct 6a and preheated. The preheated air is supplied to the combustion burner 30 via the second combustion air supply duct 6b. Here, there are cases where the entire amount of the discharge side air of the burner blower B2 does not pass through the combustion burner 30, and a part of it bypasses the combustion burner 30 and is supplied to the combustion chamber 31.

[0070] In this embodiment, the heating means is also configured to function as the processing means. That is, a part of the air containing the volatile substances in the drying chamber 2 is transferred to the combustion burner 30 via the first combustion air supply duct 6a and the second combustion air supply duct 6b, and is maintained in the combustion chamber 31 at a high temperature where the volatile substances can be decomposed, whereby the volatile substances are oxidatively decomposed.

[0071] According to this embodiment, since outside air is not used as the air supplied to the combustion burner 30, the energy saving effect is high, and since the entire amount of combustion air is transported by the burner blower B2, an exhaust fan is not required, and the path for introducing the combustion air into the combustion chamber 31 can be simplified.

[0072] The controller is configured to adjust the amount of combustion air based on the VOC load in the drying chamber 2 so that the temperature in the combustion chamber 31 is maintained within a set range.

[0073] In addition, in this embodiment, the amount of outside air introduced is adjusted by the controller and the outside air introduction fan B3 so that the flow rate of the first outside air introduction duct 8a is approximately the same as the amount of combustion air in the first combustion air supply duct 6a or the exhaust amount of the third exhaust duct 7c.

[0074] Other embodiments 1. In the above-described embodiment, a filter device may be provided in the air recovery duct 5 or in the air supply duct 4, if necessary. 2. The configurations and control methods in the above-described embodiments may be used in appropriate combinations as necessary.

[0075] Although the present invention has been described with reference to the drawings as described above, it goes without saying that the present invention is not limited to the configuration of the drawings, and can be embodied in various forms without departing from the gist of the present invention. [Industrial Applicability]

[0076] The paint drying equipment according to the present invention can be particularly suitably used in technical fields in which paint is dried on the entire body or various parts that constitute the body of, for example, an automobile, a railway vehicle, an aircraft, a ship, etc. [Explanation of symbols]

[0077] 1. Paint drying equipment 2 Drying room 20 Balloon Header 21 Suction header 3 Combustion furnace 30 Combustion Burner 31 Combustion chamber 32 Heat exchanger 4 Air supply duct 5 Air recovery duct 50 Filter device 6a First combustion air supply duct 6b Second combustion air supply duct 6c No. 3 combustion air supply duct 7a First exhaust duct 7b Second exhaust duct 7c 3rd exhaust duct 8a First outdoor air intake duct 8b Second outdoor air intake duct 8c Third outdoor air intake duct 9a First outside air intake 9b Second outside air intake section H1 1st heat exchanger H2 2nd heat exchanger B1 Air supply fan B2 Burner Blower B3 Outdoor air intake fan B4 Exhaust Fan T Combustion furnace temperature sensor F1, F2 flowmeter

Claims

1. A drying chamber for drying the object to be coated; A heating means having a heat exchanger for heating the air recovered from the drying chamber, and a combustion chamber for combusting the air recovered from the drying chamber to decompose volatile substances, In the coating drying equipment, the air heated by the heating means is supplied to the drying chamber, a first heat recovery means for recovering heat from exhaust gas discharged from the combustion chamber; A second heat recovery means for recovering heat from the exhaust gas discharged from the first heat recovery means, A coating drying facility characterized in that the air supplied from the drying chamber to the combustion chamber is supplied from the drying chamber to the first heat recovery means, and is preheated by the first heat recovery means before being supplied to the combustion chamber.

2. A paint drying equipment as described in Claim 1, characterized in that it is equipped with a fuel quantity adjustment mechanism for adjusting the amount of fuel supplied to the combustion chamber, and a combustion air quantity adjustment mechanism for adjusting the amount of air supplied to the combustion chamber.

3. 3. The paint drying equipment according to claim 2, wherein the combustion air amount adjustment mechanism increases the amount of air supplied to the combustion chamber when the temperature inside the combustion chamber exceeds a set upper limit value, and decreases the amount of air supplied to the combustion chamber when the temperature inside the combustion chamber falls below a set lower limit value.

4. 4. The coating drying equipment according to claim 2, further comprising: an outside air introduction means for introducing outside air into the drying chamber; and an outside air introduction amount adjustment mechanism for adjusting the amount of outside air introduced into the drying chamber by the outside air introduction means.

5. 5. The coating drying facility according to claim 4, wherein the outside air introduced by the outside air introduction means is preheated by the second heat recovery means and then supplied to the drying chamber.

6. A paint drying equipment as described in claim 4 or 5, characterized in that the amount of outside air introduced into the drying chamber by the outside air introduction means and the amount of air supplied to the combustion chamber by the combustion air volume adjustment mechanism are controlled to be approximately the same amount.

Images