JPH0457386B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a continuous drying oven, and more particularly to a continuous drying oven that prevents evaporated fume from adhering to walls from painted materials.

(Prior art) As shown in FIGS. 4 and 5, an oven for continuous drying of coated materials consists of a heating zone A and an air cooling zone B, which are connected to each other in a coating device ( For example, a plate material 1 whose surface has been painted is transferred to an oven by a conveyor 2, and delivered to an endless rotary conveyor 3 provided so as to be able to pass through a heating zone A and an air cooling zone B. After being heated and dried during transportation in step 3, it is cooled and sent out. The rotary conveyor 3 described above is provided with support racks 4 at regular intervals for supporting the coated plate materials 1 in an upright state, and the plate materials 1 on the transport conveyor 2 are transferred to the rotary conveyor 3 one after another in the delivery chamber 5. After being transferred to the support rack 4, it is placed in an upright state, and as the rotary conveyor 3 moves, it passes through the heating zone A and the air cooling zone B. The heating zone A is equipped with a hot air blower 6, a lower pressure accumulation chamber 7, a plate heating chamber 8, and an exhaust chamber 9, and the hot air sent out from the blower 6 is first sent to the lower pressure accumulation chamber 7 as shown in FIG. Then, after passing through the plate heating chamber 8, it reaches the exhaust chamber 9, and is again sent to the lower pressure accumulation chamber 7 by the blower 6 and circulated. The plate material 1 passing through the heating chamber 8 is heated and heated by the circulating hot air, but at this time flammable fume from the paint evaporates, so in order to prevent combustion explosion, the flammable fume in the circulating hot air is heated against the air. must be maintained below the lower explosive limit at all times, so air is mixed in to dilute the concentration. In order to keep the volume of circulating hot air constant, the area where the amount of evaporated fume is the largest in the heating zone A, specifically, the transfer chamber 5 of the plate material 1 at the entrance of the heating chamber A, and the transfer chamber 5 of the plate material 1 to the heating chamber A at the entrance of the heating chamber A. The atmosphere near the entrance is exhausted to the outside by an exhaust fan 10 and transferred to a deodorizing device (not shown) for deodorizing treatment.

Therefore, at the same time as outside air flows in from the entrance 11 of the delivery chamber 5, a large amount of hot air flows into the delivery chamber 5 from the boundary opening 12 between the delivery chamber 5 and the heating chamber 8. Because it is large,
A phenomenon occurs in which the low-temperature atmosphere in the delivery chamber 5 flows into the heating chamber 8.

(Problems to be Solved by the Invention) The phenomenon of the low-temperature atmosphere flowing into the heating chamber 8 from the delivery chamber 5 described above causes a temperature drop in the heating chamber 8, and the temperature drop causes the inner wall surface of the delivery chamber 5 to This causes the inconvenience that flammable fume adheres to the inner wall surface of the heating chamber 8. When flammable fume adheres to these walls, flammable gas evaporates from this adhered fume, and the inside of the heating chamber 8 contains flammable fume evaporated from the painted board material 1 and an indefinite amount of combustible gas evaporated from the adhered fume. In order to predict the presence of this high concentration of combustible fume and maintain the lower explosive limit, the combustible fume generated from the plate material 1 is The reality is that safety is ensured by introducing a large amount of diluted air, which is equivalent to an air-to-air ratio several times higher than the lower explosive limit of Huyum.

Furthermore, since the connecting portion 13 between the heating zone A and the air cooling zone B must allow the passage of the plate material 1 in an upright state, the opening 14 of the connecting portion 13 is substantially the same as that of the heating chamber 8. The size is equivalent to the vertical cross-sectional area,
Therefore, a flow of internal atmosphere inevitably occurs between heating zone A and air-cooling zone B, which causes a temperature drop in heating zone A and a temperature increase in air-cooling zone B, resulting in heating and cooling inside the oven. There is a problem that the length of the effective working area becomes short, and in order to make the length of the effective working area sufficient as described above, the length of the entire oven furnace must be increased. This not only requires a larger amount of hot air and diluted air, but also increases the amount of burner combustion, making it uneconomical.In addition, it takes a lot of time and effort to periodically remove the fume that adheres to the wall. It takes.

(Means for Solving the Problems) An object of the present invention is to effectively prevent fume from adhering to the wall surface of the oven as described above, and to prevent the atmosphere from flowing between the heating zone and the air cooling zone. The object of this invention is to improve the various problems mentioned above in ovens, and is constructed as follows. That is, as shown in FIGS. 1 and 2, the inner wall 15 of the transfer chamber 5 of the drying oven heating zone A and the heating chamber 8 near the boundary opening 12 between the transfer chamber 5 and the heating chamber 8. The inner wall 16 and the inner circumferential wall 18 of the exhaust duct 17 have a double structure with spaces 19 and 19 through which air can flow, respectively, and the high temperature exhaust gas from the deodorizing device is introduced into the spaces 19 and 19. The surface temperature of the inner walls 15, 16, and 18 is connected to 180° C. or higher, and further, the heating zone A and the air cooling zone B are substantially separated, and a pair of supports are provided for each of the heating zone A and the air cooling zone B. A heating zone conveyor 3A equipped with grooves 4a and 4b and a cooling zone conveyor 3B equipped with a receiving groove 4 are provided, and a plate material 1 is provided between both conveyors 3A and 3B.
An intermediate conveyor 20 is provided to transport the water in a horizontal state to reduce the opening area of the connecting openings 21 and 26 between the heating zone A and the air cooling zone B. , 22 are arranged facing each other to prevent free flow of air at the connection between the heating zone A and the air cooling zone B.

(Function) Next, the drying oven of the present invention configured as described above will be explained in more detail while describing its function. Spaces 19, 19, 19 are provided on the inner peripheral wall 18 of the exhaust duct 17 provided above the chamber 5 and on the surface side of the inner wall 16 of the heating chamber 8 near the opening 12 at the boundary between the delivery chamber 5 and the heating chamber 8, respectively. A corrosion-resistant metal plate is stretched to create a double structure, and pressure accumulators 23, 23 are provided above and below the inlet opening 11 of the plate 1, and the above-mentioned spaces 19, 19, 19 and the pressure accumulator 23 are provided. ，
23, the high-temperature gas discharged from the deodorizing device is introduced into the spaces 19, 19, 19 and released from the pressure accumulation chambers 23, 23, thereby causing the inner walls 15, 16 and the inner circumferential wall 18 to be in communication with each other. While maintaining the surface temperature at 180℃ or higher, the pressure accumulation chamber 23,
The flow of internal and external air at the entrance opening 11 of the delivery chamber 5 is blocked by the hot air jetted from the nozzle 23 at a rate of about 10 m/min. In this way, the temperature inside the heating chamber 8 is prevented from decreasing, and the combustible fume evaporated from the painted board material 1 does not solidify and adhere even if it comes into contact with the wall surface, and due to the exhaust action of the exhaust fan 10, it is sent to the deodorizing device along with the high temperature atmosphere. It is ejected towards.

In addition, the above-mentioned double-structured inner wall 15 of the heating zone A,
As shown in FIG. 2, the wall temperature at locations other than 16 can be reduced by causing the circulation blower 6 to blow out a high temperature atmosphere downward from the pressure accumulation chambers 24, 24 on both sides, and then blowing the high temperature atmosphere from the floor of the board heating chamber 8. The atmosphere is ejected upward to heat the plates 1, 1, flows into the exhaust chamber 25, and is divided into an atmosphere flow that returns to the blower 6 side and an air flow that moves from the exhaust fan 10 to the deodorizing device. 180 because it is always in contact with a high temperature atmosphere.
Maintains temperature above ℃ and no fume build-up occurs.

On the other hand, the heating zone A and the air-cooling zone B of the oven are substantially separated as shown, and the heating zone side conveyor 3A is provided with the above-mentioned support plates 4a and 4b, and the cooling zone side is provided with the catch plate 4, respectively. An intermediate transport conveyor 2 is installed so that the conveyors 3B rotate in synchronization in the same direction, and can sequentially transport the plate material 1 in a horizontal state between both conveyors 3A and 3B.
0 is provided at the end of the heating zone side conveyor 3A, and the plate material 1 is transferred horizontally onto the intermediate conveyor 20 at the end of the heating zone side conveyor 3A to convey the plate material 1 to the air cooling chamber B, and then transferred to the air cooling zone side conveyor 3B. The structure is such that it is brought into an upright state again by the upright action of the stopper 4 and is allowed to pass through the air cooling chamber B.

With this configuration, the opening area of the outlet opening 21 of the heating chamber 8 is significantly reduced, and pressure accumulators 22, 22 are arranged above and below the outlet opening 21, and high temperature gas is discharged from the pressure accumulators 22, 22. This prevents free flow of air between the inside and outside of the outlet section 21. Therefore, the opening 2 of the air cooling zone B of the heating chamber 8
6 or the intrusion of low-temperature air from the outside is prevented, and the atmosphere in the heating chamber 8 is maintained at a high temperature.

FIG. 3 shows an example of a flow sheet for carrying out the above-mentioned action. Based on this flow sheet, the flow of gas is explained. The atmosphere inside the chamber 8 is sent from the exhaust fan 10 to the deodorizing device 28 via the heat exchanger 27, and then to the burner 2.
After being combusted and deodorized in step 9, it is introduced into the heat exchanger 27 again and then into another heat exchanger 30. The high temperature gas in the heat exchanger 30 is then transferred to the blower 31.
is fed into the conduit 32 by the action of the conduit 3
2 to 2 to the pressure accumulation chambers 22, 22, 23, 23,
and is introduced into the spaces 19, 19 of the double-structured inner walls 15, 16 and the surrounding wall 18, and is discharged from the nozzles of the pressure accumulating chambers 22, 23 to prevent circulation of internal and external air at the outlet opening 21 and the inlet opening 11. and the surface temperature of the inner walls 15, 16 and the peripheral wall 18.
Keep at 180℃ or higher. And each of the above spaces 19,
The high-temperature gas in the chimney 19 is sent to the high-temperature chimney 33 and discharged by the exhaust fan 42. Also, the heat exchanger 30
A part of the high-temperature gas passing through is sent to the deodorizing burner 29 and the oven temperature increasing burner 34 by the blower 31, thereby increasing the temperature of the combustion air and saving fuel consumption. 35 is a combustible fume to air ratio detection device that detects the mixture ratio of flammable fume in exhaust gas;
The rotation of the exhaust fan 10 is controlled in response to an increase or decrease in the mixing ratio, and the amount of diluted air introduced from the air inlet 36 is adjusted, thereby constantly keeping the concentration of flammable fumes in the oven atmospheric gas below the explosion limit. It operates so that it is below the lower limit. As mentioned above, since the inner wall temperature of a portion of the delivery chamber 5 and the heating chamber 8 is maintained at 180° C. or higher, there is almost no adhesion of fume to the inner wall surface, and the entrance and exit port 23 of the heating zone A,
Since the inflow of outside air from the exhaust fan 11 is prevented, the amount of flammable fume evaporating from the painted board material 1 can be almost accurately detected by the detection device 35.
0 rotation control and increase/decrease in the amount of dilution air introduced, ensuring safe operation.

(Effects of the Invention) As described above, the continuous drying oven of the present invention has the inner wall 15 of the delivery chamber 5 of the heating zone A of the oven and the heating chamber 8 near the boundary opening 12 between the delivery chamber 5 and the heating chamber 8. The inner wall 16 of the exhaust duct 17 and the inner circumferential wall 18 of the exhaust duct 17 are respectively provided with a space 19 through which air can circulate.
It has a double structure with 19 interposed therebetween, and the space 1
High-temperature gas from the deodorizing device is introduced into the interiors of the heating chambers 8 and 19 to maintain the surface temperature of the inner walls 15, 16 and the inner circumferential wall 18 at 180°C or higher. Flammable fumes are prevented from adhering to the inner wall surface of the movement area of the exhaust gas toward the exhaust duct 17, and almost all of the flammable fumes evaporated from the painted plate material 1 in the heating chamber 8 are introduced into the deodorizing device. During combustion in the deodorizing device, the thermal calories of this flammable fume can be effectively used, and the value measured for the concentration of flammable fume in the exhaust duct almost matches the concentration of flammable fume in the heating chamber 8. Therefore, the introduction of dilution air can be effectively controlled in order to control the atmosphere within the heating chamber 8 to the lower explosive limit.

Further, the heating zone A and the air cooling zone B are substantially separated, and each of the heating zone A and the air cooling zone B is provided with a heating zone side conveyor 3A and a receiving tube 4, respectively. A belt side conveyor 3B is provided, and a plate material 1 is installed between both conveyors 3A and 3B.
An intermediate conveyor 20 is provided to transport the heating zone A and the air cooling zone B in a horizontal state to reduce the opening areas of the openings 21 and 26 at the connection between the heating zone A and the air cooling zone B.
Since the pressure accumulating chambers 22, 22 and 23, 23 are disposed facing each other at the entrance and exit of the heating zone A, air circulation at the entrance and exit of the plate material 1 of the heating zone A is substantially prevented, and low-temperature air flows into the heating chamber 8. This reduces heat loss, making it possible to maintain a high temperature in the heating chamber 1 even with a small amount of combustion, and achieving dramatic energy savings.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view illustrating the drying oven of the present invention, FIG. 2 is a front sectional view taken along line AA in FIG. FIG. 5 is a side sectional view of a conventional drying oven, and FIG. 5 is a front sectional view taken along the line A--A in FIG. A... Heating zone, B... Air cooling zone, 1... Painted plate material, 2... Conveyor, 3A... Heating zone side conveyor equipped with a pair of support strips, 3B... Cooling zone equipped with support strips. Side conveyor, 4...Supporting rack, 4
a, 4b...a pair of support racks, 5...transfer room,
8... Heating chamber, 11... Inlet opening, 12... Boundary opening between delivery chamber and heating chamber, 15... Inner wall of delivery chamber, 16... Inner wall of heating chamber near boundary opening, 17... ...Exhaust duct, 18...Inner peripheral wall of exhaust duct, 19...Space, 20...Intermediate conveyor, 21...Exit opening, 22, 23...
Pressure accumulation chamber.

Claims (1)

[Claims] 1 Inner wall 1 of delivery chamber 5 of heating zone A of oven
5 and the boundary opening 1 between the delivery chamber 5 and the heating chamber 8
The inner wall 16 of the heating chamber 8 and the inner circumferential wall 18 of the exhaust duct 17 in the vicinity of No. 2 have a double structure with spaces 19, 19 through which air can flow, respectively, and the deodorizing device exits into the spaces 19, 19. Each of the inner walls 15, 16 and the inner peripheral wall 18 are heated by introducing high temperature gas.
The heating zone A and the air cooling zone B are substantially separated, and each of the heating zone A and the air cooling zone B is provided with a pair of support plates 4a and 4b. A heating zone side conveyor 3A equipped with a cooling zone side conveyor 3B equipped with a catch plate 4 is provided, and both conveyors 3A, 3B are provided.
An intermediate conveyor 20 for horizontally transporting the plate material 1 is provided in between to reduce the opening area of the connecting openings 21 and 26 between the heating zone A and the air cooling zone B, and a pair of upper and lower openings are provided at the entrance and exit of the heating zone A. A continuous drying oven characterized in that pressure accumulation chambers 22, 22 and 23, 23 are arranged facing each other.