JPS635815Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a paint drying oven.

For example, when painting objects that require high quality such as automobile bodies, indirect convection is used in the first half of the zone in the direction of movement of the object to be dried, while the second half is Direct convection type paint drying ovens are often used.

In the indirect convection method, a part of a circulation duct that forms a closed path is placed inside the drying oven along its length, and the heat of the high-temperature airflow (hot air) circulating inside this duct is transferred to the duct. The heat is transferred to the air inside the furnace via a heat transfer panel installed on the side where the material to be dried passes through.
The temperature of the air inside the furnace is raised by thermal convection, and the material to be dried is dried. The hot air flowing through the duct is
It is discharged to the outside of the system via an exhaust duct connected to this circulation duct.

The above-mentioned indirect convection method uses hot air flowing inside the circulation duct to indirectly raise the air inside the furnace and dry the material to be dried. The heat transfer efficiency is poor compared to the conventional method, and in order to raise the air inside the furnace above a certain temperature, the temperature of the air inside the duct must be raised considerably. Furthermore, since the hot air inside the duct is exhausted after flowing through the duct, there is also the problem that there is a large amount of exhaust heat loss.

The present invention relates to an improvement of the above-mentioned conventional indirect convection type paint drying oven.By installing a member with a good heat transfer coefficient on the heat transfer panel of the circulation duct, the temperature of the hot air inside the circulation duct can be lowered. Another object of the present invention is to provide an indirect convection type paint drying oven that can efficiently increase the temperature of the air near the passage of the material to be dried, and can therefore also reduce exhaust heat loss.

The paint drying oven of the present invention has a heat transfer panel installed on the surface of the in-furnace hot air circulation duct on the side where the material to be dried passes. A heat member is provided to penetrate the heat transfer panel.

Hereinafter, the paint drying oven of the present invention will be explained in more detail based on the drawings.

Fig. 1 is a schematic top view showing an example of the paint drying oven of the present invention, Fig. 2 is a schematic cross-sectional view taken along the line - in Fig. 1,
FIG. 3 is a schematic cross-sectional view taken along the - line in FIG. 1.

As shown in Figures 1 and 2, a paint drying oven 1
consists of an indirect convection furnace 2 located in the first half zone in the direction of conveyance of the material to be dried (indicated by white arrows in the figure), and a direct convection furnace 3 located in the second half zone.

The indirect convection furnace 2 includes a pair of hot air circulation ducts (hereinafter simply referred to as the inside of the duct furnace) 4a and 4b, which are arranged on both sides of a coating zone of a predetermined length in the longitudinal direction of the zone. , consisting of a ceiling plate 6 with a substantially U-shaped cross section bridged over the top of these duct furnace interiors 4a, 4b, and a furnace shell 7 that covers these duct furnace interiors 4a, 4b and the ceiling plate 6 from the outside. .
The material to be dried A is carried into a drying chamber 8 comprised of duct furnace interiors 4 a and 4 b and a ceiling plate 6 . The material to be dried A is placed on a trolley a ₃ having rails a ₁ and a ₂ at its lower end, and is transported through the furnace.

Heat transfer panels 5a and 5b with excellent heat conduction are provided on the surfaces of the duct furnace interiors 4a and 4b facing the material to be dried A, and the duct furnace interiors 4a and 4b are connected to each other through the heat transfer panels 5a and 5b. The heat of the flowing high-temperature air is transferred to the drying chamber 8. In Figure 2, 9, 9,...
is a support rod that supports each duct furnace interior 4a and 4b.

Both end portions of the duct furnace interior 4a constitute circulation system paths that extend from the inlet and outlet portions of the furnace to the outside of the furnace and connect to each other. Hot air circulation duct formed outside the furnace (hereinafter referred to as duct outside the furnace) 4
In c, the combustion device 10 is provided upstream from the furnace 2, and the fan 11 is provided downstream from the furnace 2. Further, an exhaust duct 12 is connected between the combustion device 10 and the fan 11. Both ends of another duct furnace interior 4b extend across the coating zone, are connected to both ends of the duct furnace interior 4a, and similarly form a circulation path together with the duct furnace exterior 4c.

An air suction duct (not shown) is connected to the combustion device 10, and air sucked through the duct is combusted by a burner (not shown) provided in the combustion device 10. Combustion gas, that is, hot air is transferred from the duct furnace exterior 4c to the respective duct furnace interiors 4a and 4b.
It flows through the duct furnace interiors 4a and 4b due to the suction force of the fan 11, and after exiting the furnace 2, it is exhausted to the outside of the system via the exhaust duct 12.

Numerous heat pipes 13, 13, . . . are attached to heat transfer panels 5a, 5b provided in the in-furnace duct portions 4a, 4b. The heat pipe 13 is a pipe with a high thermal conductivity medium sealed inside and closed at both ends, and is fixed through holes drilled in the heat transfer panels 5a and 5b. The heat pipe 13 is connected to the heat transfer panel 5
They may be simply fitted into holes provided in holes a and 5b, or special fixing means may be provided.

For example, as shown in FIG. 3, the heat pipes 13, 13, . Install this. In this way, there are fewer heat pipes 13 on the furnace entrance side of the duct furnace interior 4a through which high-temperature hot air passes, and there are fewer heat pipes 13 on the furnace exit side where the temperature gradually decreases.
3 is provided in large numbers, the heat supplied to the material to be dried A passing through the furnace becomes uniform, which is preferable. The same applies to the mounting density of heat pipes to the heat transfer panel 5b.

Further, the position of the heat pipe 13 at which it is attached to the heat transfer panels 5a, 5b may be appropriately adjusted according to the outer shape of the material A to be dried. That is, in accordance with the uneven shape of the surface facing the heat transfer panels 5a and 5b of the material to be dried A passing through the oven, the heat pipe 13 located at a position corresponding to the concave portion of the material to be dried A is aligned with its axial center in the drying chamber. 8 side, and the heat pipe 13 at the position corresponding to the convex portion has its axial center aligned with the inside of the duct furnace 4a,
heat transfer panels 5a, 5b so as to be shifted inside of 4b.
Attach to. Further, the positions of the heat pipes 13, 13, . . . may be adjusted as appropriate depending on the material of the object to be dried, that is, a portion formed of a material with a large heat capacity and a portion formed of a material with a small heat capacity. In the figure, reference numerals 18 and 18 are air jet pipes for promoting convection of the air inside the drying chamber 8.

3 is a direct convection furnace connected to the outlet end of the indirect convection furnace 2 configured as described above. The direct convection furnace 3 has almost the same configuration as the indirect convection furnace 2, and communicates with the hot air circulation duct 14, the combustion device 15 and fan 16 disposed in the hot air circulation duct 14, and the hot air circulation duct 14. It has an exhaust duct 17. Also in the direct convection oven 3, a duct oven of a circulation duct 14 is disposed in the longitudinal direction, and the hot air flowing inside the duct oven is directly blown onto the material to be dried A to dry it. The hot air supplied to the drying room is
After being sucked in by the fan 16, the exhaust duct 1
7 to the outside of the system.

In the coating drying oven 1 having the above configuration, the material to be dried A placed on the trolley _a3 is conveyed to the drying chamber 8 of the indirect convection oven 2 from the direction indicated by the arrow in FIG. The temperature of the drying chamber 8 is determined by the heat of the hot air flowing from the outside 4c of the hot air circulation duct to the insides 4a and 4b of the duct furnace.
The heat is transferred through the drying chamber 8, and the drying material A passing through this drying chamber 8 is dried. The material to be dried A is then directly conveyed to the convection oven 3, where it is further completely dried, and then transported out of the drying oven 1.

As described above, the indirect convection furnace 2 has a large number of heat pipes 13, 13... attached to the heat transfer panels 5a, 5b that pass through the heat transfer panels, so that the heat inside the duct furnace 4a, 4b can be effectively dried. can be transmitted to the air in chamber 8. Since the upper surface of the drying chamber 8 is covered with the ceiling plate 6, heat convection occurs inside the drying chamber 8 without the transferred heat being diffused throughout the oven. Therefore, the air around the area through which the material to be dried A passes is efficiently heated. In particular, heat pipe 1
If the protruding ends of the drying chamber 8 of 3, 13, etc. are adjusted appropriately to follow the outer shape of the material to be dried, the material to be dried can be dried not only by convective heat transfer of the air in the drying chamber 8 but also by radiant heat transfer. This helps to raise the temperature of A, further improving the drying effect. Therefore, the temperature of the hot air flowing through the hot air circulation ducts 4a, 4b can be lowered compared to the conventional structure, so that exhaust heat loss can be reduced.

Specifically, in order to raise the temperature of the material to be dried A to 150°C, the hot air temperature on the inlet side of the hot air circulation ducts 4a and 4b, which was conventionally heated to about 350°C, becomes about 250°C.
The surface temperature of the heat transfer panels 5a and 5b at this time is
The temperature decreased from 250°C to 180°C, and the temperature of the hot air exhausted from the exhaust duct 12 decreased from about 300°C to about 200°C.

The heat transfer member used in the present invention is not limited to the above-mentioned heat pipe, but any material having good thermal conductivity may be used. As the heat transfer member, heat transfer rods, heat transfer plates, etc. made of materials with good thermal conductivity can be used, and both are placed in the heat transfer panel, with a part located inside the hot air circulation duct and the other part located inside the drying room. It is installed as follows.

Furthermore, the present invention is not limited to a structure in which an indirect convection furnace and a direct convection furnace are connected as in the above example;
It goes without saying that the present invention can also be applied to a paint drying oven consisting only of an indirect convection oven.

As detailed above, the paint drying oven of the present invention has a structure in which a heat transfer member is attached to the heat transfer panel provided on the surface of the hot air circulation duct in the oven on the side where the material to be dried passes, so that the air flowing through the circulation duct is Since the heat of the hot air can be well transferred to the air in the vicinity through which the material to be dried passes, the temperature of the hot air in the hot air circulation duct can be lowered compared to conventional ones. Therefore, it has the advantage that the energy required for heating can be reduced and exhaust heat loss due to hot air exhaust can be reduced.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of a paint drying oven, FIG. 2 is a schematic cross-sectional view taken along the - line in FIG. 1, and FIG. 3 is a schematic cross-sectional view taken along the - line in FIG. In the figure, 1...Paint drying oven, 2...Indirect convection oven,
3... Direct convection furnace, 4a, 4b... Inside the duct furnace, 4c... Outside the duct furnace, 7... Furnace shell, 8...
Drying chamber, 10... combustion device, 13... heat pipe.

Claims (1)

[Scope of Claim for Utility Model Registration] Consisting of a furnace body, a hot air circulation duct disposed inside the furnace body, and a heat transfer panel provided on the surface of the hot air circulation duct on the side through which the material to be dried passes, In an indirect convection type paint drying furnace that transmits heat of hot air flowing through the circulation duct to air inside the furnace body via the heat transfer panel, the heat transfer panel penetrates the heat transfer panel, and a part of the heat transfer panel A paint drying furnace characterized by comprising a heat transfer member located inside a circulation duct and the other part located inside the furnace body.