JP3655461B2 - drying furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drying furnace used for drying a paint applied to an object to be coated such as an automobile body or drying printing ink printed on paper or plastic.
[0002]
[Prior art]
For example, in an automobile body painting line, a drying furnace that dries the paint film is installed after the paint booth where the paint is sprayed. The coating film formed on the surface is dried.
The drying furnace is maintained at a temperature of about 100 to 160 ° C., and the coating film is dried and cured by evaporating moisture and organic solvent contained in the paint. Therefore, the concentration of the organic solvent gradually increases in the furnace, If left untreated, the organic solvent contained in the polluted air aggregates on the surface of the object to be coated such as an automobile body, fading the original color of the paint, resulting in a coating failure called yellowing.
For this reason, in a general drying furnace, polluted air (exhaust gas) is always discharged from the furnace body, and this is purified by an exhaust gas treatment device and then circulated and supplied to the furnace body or released to the atmosphere. .
[0003]
[Problems to be solved by the invention]
However, since the contaminated air convects inside the furnace before it is discharged to the outside, the evaporated organic solvent contained in the contaminated air is exposed on the exposed surface of the furnace body such as side walls, ceiling walls, floor walls, and partition walls. There was a problem that it aggregated and adhered as a spear.
In particular, when spears that adhere to the ceiling wall grow, they can be smudged onto the object to be coated, resulting in poor painting. In order to prevent this, even depending on the type of paint used, usually every two to three weeks. The furnace must be cleaned weekly.
In addition, the drying oven for painting the automobile body has a length of several hundreds of meters, and the cleaning work has to be relied on manually, which requires a lot of labor and the cost of the cleaning work increases. .
[0004]
In addition, the coating drying furnace has a large volume because it has a long overall length, and the exhaust gas treatment device requires a large amount of exhaust gas that is continuously discharged from the drying furnace. There was a problem that maintenance costs and running costs required for exchanging consumables and for cleaning the inside of the duct leading to the exhaust gas treatment apparatus increased.
In addition, the drying oven for printing is not as good as the drying oven for coating, but it is the same as the drying oven for coating in that the organic solvent components evaporate from the printing ink. It is the same.
[0005]
Thus, the present invention reduces labor required for cleaning operations in a drying furnace such as a coating drying furnace or a printing drying furnace, and also reduces the load on the exhaust gas treatment device, thereby significantly reducing maintenance costs and running costs. Is a technical issue.
[0006]
[Means for Solving the Problems]
In order to solve this problem, the present invention relates to a drying furnace in which contaminated air containing an evaporated organic solvent is generated by drying a workpiece in the furnace body, and the exposed surface of the furnace body or the air in the furnace body circulates. A water electrolysis promoter obtained by kneading pyroelectric material powder with a heat-resistant inorganic adhesive is coated on the inner surface of the duct.
[0007]
In the drying furnace according to the present invention, for example, when an automobile body painted with a paint containing an organic solvent is carried into the furnace and heated, the coating film is dried and cured.
At this time, since the surface of the furnace body and the inner surface of the duct through which the air in the furnace body flows are coated with a water electrolysis promoter kneaded pyroelectric material powder in a heat-resistant inorganic adhesive, When the pyroelectric material is heated, a negative charge appears on the exposed surface in the furnace and the inner surface of the duct due to the pyroelectric effect.
On the other hand, when the workpiece is heated, moisture and organic solvent evaporate from the undried coating film, which adheres to the exposed surface and the inner surface of the duct as a result of convection of the air in the furnace body, and becomes a spear.
And the water molecules contained in this spider receive the electrons that appear due to the pyroelectric effect, and some of them
H ₂ O + 2e ⁻ → O ² + + H ₂
H ₂ O + e ⁻ → O ⁻ + H ₂
Is electrolyzed into hydrogen and ionized oxygen.
And this ionized oxygen reacts with the organic substance which is the main component of the spear adhering to the exposed surface in a furnace body, oxidizes this, and decomposes | disassembles into water and a carbon dioxide.
Therefore, the scum adhering to the exposed surface of the furnace body is gradually decomposed and reduced, and accordingly, the frequency and labor of the cleaning work are reduced, and the load of the exhaust gas treatment device is also reduced. , Running cost is reduced.
[0008]
Furthermore, another drying furnace according to the present invention is an oxygen active material in which ceramic powder containing a radioactive element is kneaded with a heat-resistant inorganic adhesive on the exposed surface in the furnace body or the inner surface of the duct through which air flows in the furnace body. Chemical material is applied.
According to this drying furnace, from the radioactive elements contained in the oxygen-activated material coated on the exposed surface of the furnace body to the water molecules contained in the spear adhered and agglomerated on the exposed surface of the furnace body and the inner surface of the duct. Irradiated with radiation, some of which
3H ₂ O → O ₃ + 3H ₂
2H ₂ O → O ₂ + 2H ₂
Water is separated into hydrogen and oxygen by the reaction represented by the following, whereby oxygen and ozone are obtained.
Therefore, these oxygen and ozone react with the organic matter that is the main component of the ani, and oxidize it and decompose it into water and carbon dioxide, so that the ani adhering to the exposed surface in the furnace and the inner surface of the duct gradually Disassembled to lose weight.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an explanatory view showing a drying furnace according to the present invention, and FIG. 2 is a schematic view showing a chemical change in the furnace body. For convenience of explanation, in FIG. 1, the right side shows a radiant heating zone in which the furnace body is heated with a dark red panel, and the left side shows a convection heating zone in which hot air is blown out to heat the furnace body.
[0010]
The drying furnace 1 according to the present example is used as a drying furnace for painting an automobile body, and is continuously provided in a painting booth (not shown). In the furnace body 2, an automobile body serving as a workpiece W is provided. The conveyor 3 to convey is laid along the longitudinal direction.
And the radiant heating zone 4A which dries an undried coating film to a dry state is formed in the front | former stage side of the drying furnace 1, and the convection heating which bakes and dries the coating film dried in the radiant heating zone 4A in the back | latter stage side. Zone 4B is formed.
[0011]
In the radiant heating zone 4 </ b> A, a dark red panel 6 to which hot air is circulated and supplied from the hot air generator 5 is disposed, and the interior of the furnace body 2 is heated by the radiant heat of the dark red panel 6.
In the convection heating zone 4 </ b> B, a hot air circulation system 10 is formed in which hot air sucked from the hot air suction duct 7 is heated by the heat exchanger 8 and then blown out from the hot air blowing duct 9. Are formed with gate-type partition walls 2P at predetermined intervals to prevent the lateral flow of hot air blown out from the hot air blowing duct 9.
Reference numeral 12 denotes an exhaust gas suction duct for discharging contaminated air generated in the furnace body 2, and 13 is an exhaust gas treatment device for purifying the contaminated air (exhaust gas) discharged through the exhaust gas suction duct 12.
[0012]
And the left and right side walls 2L and 2R in the furnace body 2, the ceiling wall 2U, the floor wall 2F, the partition wall 2P, the outer surface of the dark red panel 6, the outer surface of the hot air suction duct 7 and the hot air blowing duct 9, etc. A water electrolysis promoter 16 in which pyroelectric material powder is kneaded with a heat-resistant inorganic adhesive is applied to the exposed surface 14, the ducts 7 and 9 of the hot air circulation system 10, and the inner surface 15 of the exhaust gas suction duct 12. [0013]
Here, as pyroelectric materials, for example, tourmaline (tourmaline), quartz (SiO ₂ ), lithium tantalate (LiTaO ₃ ), lead titanate (PbTiO ₃ ), PZT porcelain (zirconate titanate) Any material that causes a pyroelectric action at the furnace temperature of the drying furnace, such as lead: a solid solution of PbZrO ₃ and PbTiO ₃ , can be employed.
Further, it may be a mixed powder in which quartz (SiO ₂ ) is mixed with at least one of feldspar, zircon (ZrSiO ₄ ) and titanium oxide (TiO ₂ ).
All of these pyroelectric materials exhibit a pyroelectric effect when heated to about the atmospheric temperature of the drying furnace, and electric charges appear on the surface thereof.
[0014]
In addition, as the inorganic adhesive constituting the water electrolysis promoter 16, a heat-resistant inorganic adhesive that exhibits bond strength by low-temperature treatment (500 ° C.) such as water glass, colloidal silica, colloidal alumina, or the like is used.
And the water electrolysis promotion material 16 which knead | mixed the powder of the pyroelectric material mentioned above with the heat-resistant inorganic adhesive is the ducts 7 and 9 through which the exposed surface 14 in the furnace body 2 and the air in the furnace body 2 circulate. The inner surface 15 of the twelve steel plates 17 is coated with a thickness of 10 μm to 1 mm.
The coating method may be spraying by air atomization or coating by a roll coater or the like.
In addition, since the thermal expansion coefficients of the water electrolysis promoter 16 and the steel plate 17 are different, when the water electrolysis promoter 16 is applied thickly, it is not applied uniformly over the entire surface of the steel plate 17 but is applied discontinuously. If this is done, the water electrolysis promoter 16 will not crack even if the steel plate 17 is thermally expanded.
[0015]
The above is an example configuration of the present invention, and its operation will be described next.
When the drying furnace 1 is started and the inside of the furnace body 2 rises to a predetermined drying temperature, the automobile body serving as the workpiece W is conveyed by the conveyor 3 and the coating film is dried.
At this time, moisture and organic solvent contained in the coating film evaporate, and with the convection of the air in the furnace body 2, the ceiling wall 2U, left and right side walls 2R and 2L, floor wall 2F, partition wall 2P, dark red panel 6, the outer surface of the hot air suction duct 7, and the outer surface of the hot air blowing duct 9, such as the outer surface 14 in the furnace body 2, and circulates through the ducts 7 and 9 of the hot air circulation system 10 and the exhaust gas suction duct 12. Then, it adheres to the inner surface 15 and agglomerates.
[0016]
On the other hand, on the exposed surface 14 in the furnace body 2 and the inner surface 15 of each duct 7, 9, 12, a water electrolysis promoter 16 in which a pyroelectric material powder is kneaded with a heat-resistant inorganic adhesive is applied. When the pyroelectric material contained therein is heated, electric charges appear on the exposed surface 14 in the furnace body 2 and the inner surfaces 15 of the ducts 7, 9, 12 due to the pyroelectric effect.
Here, water molecules contained in the surface adhering to the exposed surface 14 and the inner surface 15 of the duct 12 receive electrons appearing on the surface of the water electrolysis promoter 16, and a part of them
H ₂ O + 2e ⁻ → O ² + + H ₂
H ₂ O + e ⁻ → O ⁻ + H ₂
Is electrolyzed into hydrogen and ionized oxygen.
And this ionized oxygen reacts with the organic substance which is the main component of the spear adhering to the exposed surface 14 etc. in the furnace body 2, oxidizes this, and decomposes | disassembles into water and a carbon dioxide.
[0017]
Therefore, since the dirt adhering to the exposed surface 14 in the furnace body 2 and the inner surface 14 of the duct 12 is gradually decomposed and reduced, the frequency and labor of the cleaning operation are reduced correspondingly, and the exhaust gas treatment device. The load of 13 is also reduced, and maintenance costs and running costs are reduced.
[0018]
Further, oxygen activity obtained by kneading ceramic powder containing a radioactive element on the exposed surface 14 in the furnace body 2 and the inner surfaces 15 of the ducts 7, 9, 12 instead of the water electrolysis promoter 16 in a heat-resistant inorganic adhesive. It may be a case where the chemical 18 is applied.
As the radioactive element, thorium (Th), uranium (U), actinium (Ac), neptunium (Np), or the like is used.
[0019]
In this case, the radioactive element contained in the oxygen activating material coated on the exposed surface 14 in the furnace body 2 is included in the spear adhered and aggregated on the exposed surface 14 in the furnace body 2 and the inner surface 15 of the duct 12. When water molecules are irradiated with radiation, some of them
3H ₂ O → O ₃ + 3H ₂
2H ₂ O → O ₂ + 2H ₂
Water is separated into hydrogen and oxygen by the reaction represented by the following, whereby oxygen and ozone are obtained.
Therefore, these oxygen and ozone react with the organic substance that is the main component of the spider and oxidize it to decompose into water and carbon dioxide, so that they adhere to the exposed surface 14 in the furnace body 2 and the inner surface 15 of the duct 12. Yani is gradually decomposed and reduced in weight.
[0020]
It is to be noted that a water electrolysis promoter 16 in which pyroelectric material powder is kneaded in the heat-resistant inorganic adhesive, or an oxygen activation material 18 in which ceramic powder containing a radioactive element is kneaded in heat-resistant inorganic adhesive is applied. When water electrolysis-promoting tiles made of ceramics kneaded with pyroelectric material powder or oxygen-activated tiles made of ceramics containing radioactive elements are pasted with an inorganic adhesive, etc. It may be.
In this way, if it is made into a tile, the quality can be maintained constant by manufacturing the tile industrially, and since it is only necessary to paste the tile, the construction is simple and the case of coating There is an advantage that anyone can finish uniformly without causing uneven coating as compared to.
In this case, it is desirable to fill the tile joint with a heat-resistant and elastic filler so as not to clog the tile joints.
[0021]
【The invention's effect】
As described above, according to the present invention, the moisture contained in the spear adhering to the exposed surface in the furnace body and the inner surface of the duct is decomposed into hydrogen and oxygen, and the organic matter that becomes the main component of the spear is decomposed by the oxygen. Because it is oxidized and decomposed into water and carbon dioxide, the amount of scum adhering to the exposed surface is reduced naturally, reducing the frequency and labor of cleaning work, and at the same time reducing the load on the exhaust gas treatment device There is an excellent effect that the cost and the maintenance cost can be reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a drying furnace according to the present invention.
FIG. 2 is a schematic diagram showing chemical changes in the furnace.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Drying furnace 2 ... Furnace body W ... Work piece 7 ... Hot-air suction duct 9 ... Hot-air blowing duct 14 ... The exposed surface 15 in a furnace body ... The inner surface 16 of a duct ... -Water electrolysis promoter 18 ... oxygen activation material

Claims (4)

In a drying furnace in which contaminated air containing an evaporated organic solvent is generated by drying the workpiece (W) in the furnace body (2), the exposed surface (14) in the furnace body (2) or the furnace body (2 The inner surface (15) of the duct (7, 9, 12) through which the air in the interior circulates is coated with a water electrolysis promoter (16) in which pyroelectric material powder is kneaded with a heat-resistant inorganic adhesive. A drying furnace characterized by that. In a drying furnace in which contaminated air containing an evaporated organic solvent is generated by drying the workpiece (W) in the furnace body (2), the exposed surface (14) in the furnace body (2) or the furnace body (2 ) Oxygen-activated material (18), in which ceramic powder containing radioactive elements is kneaded with heat-resistant inorganic adhesive, is applied to the inner surface (15) of the duct (7, 9, 12) through which air flows. A drying furnace characterized by having In a drying furnace in which contaminated air containing an evaporated organic solvent is generated by drying the workpiece (W) in the furnace body (2), the exposed surface (14) in the furnace body (2) or the furnace body (2 ) A water electrolysis facilitating tile made of ceramic that is kneaded and fired with pyroelectric material powder is affixed to the inner surface (15) of the duct (7, 9, 12) through which the air flows. Features a drying oven. In a drying furnace in which contaminated air containing an evaporated organic solvent is generated by drying the workpiece (W) in the furnace body (2), the exposed surface (14) in the furnace body (2) or the furnace body (2 ) A drying furnace characterized in that an oxygen-activated tile made of ceramic containing a radioactive element is attached to the inner surface (15) of the duct (7, 9, 12) through which the air in the inside flows.

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