JPS5934947B2 - Paint drying oven - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paint drying and baking furnace, and more particularly to a paint drying and baking furnace that can treat harmful substances generated in the furnace for the purpose of pollution control and safe operation when drying and baking paint on automobile bodies and the like. .

In conventional paint drying and baking furnaces, various pollution countermeasures have been taken to remove harmful substances including organic substances generated, and although there have been some successes, all of these measures have been taken to eliminate harmful substances emitted from the furnace. This method processes the gas outside the furnace, which requires constantly processing high concentrations of harmful gases, which not only increases equipment costs but also reduces the consumption of processing agents such as activated carbon and absorption liquid. In addition, when combustion treatment is used, fuel consumption increases, leading to a rise in operating costs.

Furthermore, the high concentration of organic harmful substances in the furnace often adversely affects the coating quality of the object to be coated.

Additionally, since the paint drying and baking furnace is used for continuous processing, there are usually no doors installed at the entrance and exit, and an air curtain system is used to prevent the gas inside the furnace from leaking to the outside. There may be some leakage to the outside.

In this case as well, when the concentration of organic substances in the furnace is high, the working environment deteriorates, such as stinging the eyes of workers, and various problems remain from the standpoint of safe operation.

The purpose of the present invention is to eliminate the drawbacks of the pollution control measures in the conventional paint drying and baking furnaces, to be able to treat organic substances in the furnace, to improve the quality of the coating on objects to be painted, and to solve the problem of pollution and improve the quality of the work. An object of the present invention is to provide a paint drying and baking furnace that can improve the environment.

In order to achieve such an object, the present invention has a fireproof wall that surrounds the top, bottom, left and right, an entrance/exit for painted objects arranged at both ends of the longitudinal direction of the fireproof wall, and a continuous flow path for moving the painted objects from the entrance to the exit. a suction duct provided along the longitudinal direction of the fireproof wall and having a suction port for sucking in a part of the air inside the furnace and introducing it into the duct outside the furnace; a blow-off duct provided at the bottom of the furnace and disposed below the suction port, and blows hot air from the outside-furnace duct into the furnace through the blow-off port; A low-temperature active catalyst is provided in at least one of the suction port and the blow-off port of the blow-off duct.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Embodiment 1 FIG. 1 is a cross-sectional view of a paint drying and baking furnace for automobile bodies. , the entrance/exit is blocked from outside air by an air curtain.

The painted automobile body 2 is suspended by a conveyor 4 attached to a conveyor rail 3, and is successively and continuously transferred from an inlet to an outlet.

The air that heated the painted automobile body 2 inside the furnace is sucked in through the suction port 9 of the suction duct 5 provided extending in the length direction at both upper ends of the furnace, and is collected in a duct outside the furnace (not shown). The duct is reheated by a burner (not shown) installed in the middle of the duct, and is then passed through a circulation fan (not shown) to a blow-off duct 6 installed extending in the length direction of both ends of the lower part of the furnace. will be introduced in

The hot air introduced into the blow-off duct 6 is normally about 200°C, and is blown out from the blow-off duct 6 through the blow-off lower into the furnace again.
After heating the painted automobile body 2, the temperature drops to about 140°C and the material is introduced into the suction duct 5 via the suction port 9 again. Platinum-based low-temperature active catalysts 8 and 10, which can undergo an active reaction even at a relatively low temperature, are provided, and harmful organic substances contained in the circulating hot air are oxidized and removed by the oxidizing action of the low-temperature active catalysts.

In this case, the low-temperature active catalyst provided at the suction port and the blowout port has S, V, (space, velocity
) value, removal rate, etc., it may be provided at both or either of the suction port and the blowout port.

Note that S and VJii here are the values obtained by dividing the amount of gas to be treated by the amount of catalyst, so a high S, V value means that a large amount of gas to be treated with a small amount of catalyst. This means that it can process the amount of

That is, S, V. The higher the value, the better the performance of the catalyst.

In addition, these S and V values are determined in advance, such as what value is for a harmful substance removal rate of 80% under a constant temperature condition, or what value is for a harmful substance removal rate of 95%. .

■If the 0 curve is fixed and you want the 80 coefficient removal rate, calculate the values of S and V from that curve.
This makes it possible to find an appropriate amount of catalyst relative to the amount of gas to be treated.

In addition, in the conventional method in which a low-temperature active catalyst is not provided at the suction port and the blowout port, the concentration of harmful organic substances in the hot air circulating in the furnace tends to gradually increase, but in the case of the present invention, the concentration of harmful organic substances in the hot air circulating in the furnace gradually increases. 70 parts of organic substances are removed, and about 30 parts of the remaining 30 parts are removed at the suction port 9, that is, 9 to 10 parts of the total, so about 80 parts of organic substances are removed as a whole. confirmed.

Example 2 FIG. 2 shows another embodiment of the invention.

The structure of the furnace itself is the same as that of the embodiment shown in FIG. Continuously transferred to the outlet.

The hot air that heated the automobile body 2 is passed through the suction port 19 of the suction duct 15 provided in the longitudinal direction along the ceiling in the upper center of the furnace.
It is sucked into the furnace, collected in a duct outside the furnace (not shown), reheated by a burner (not shown) midway through, and further extended in the length direction of both upper ends of the furnace via a circulation fan (not shown). The air is introduced into the blow-off duct 16 , and is blown out into the furnace from the blow-off port 17 of the blow-off duct 16 .

During this circulation cycle, low-temperature active catalysts 1B and 20 similar to those in Example 1 are provided at the outlet 17 and suction port 19, and harmful organic substances in the circulating hot air are oxidized and removed by the oxidation action of the low-temperature active catalysts 18 and 200.

In this case as well, the low-temperature activated catalyst may be provided at either or both of the suction port 19 and the blowout port 17 depending on its S, V, value, removal rate, etc.

In the case of this example as well, as in Example 1, it was confirmed that about 80 units of harmful substances were removed overall.

Some of the effects of the present invention have already been described, but in the conventional technology, the concentration of organic substances in the furnace is high, and the treatment equipment for treating this high concentration exhaust gas is also large-sized, resulting in an increase in equipment costs. Furthermore, in addition to the fuel consumption when performing combustion treatment, when activated carbon and absorbents are used, the consumption of these treatment agents also increases, so the drawbacks that caused the increase in operating costs can be completely eliminated. According to the present invention, most of the organic substances are oxidized and removed during circulation in the furnace.
Even when processing harmful gases discharged outside the furnace, the processing equipment can be extremely small due to the low concentration, resulting in extremely low fuel consumption or consumption of processing agents such as activated carbon and absorbents. Furthermore, in the prior art, no consideration was given to the fact that the high concentration of organic substances in the furnace adversely affects the quality of the painted object, but according to the present invention, harmful substances Since the concentration in the furnace is reduced, extremely good coating quality can be maintained.

Furthermore, as the concentration of hazardous substances in the furnace decreases as described above, there is no fear of injury to workers even if some hazardous gas leaks from the air curtain at the entrance/exit, improving the working environment and ensuring safe operation. I was able to achieve the same effect as a dog.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a paint drying and baking furnace in Example 1 according to the present invention, and FIG. 2 is a cross-sectional view of Example 2. 1... Fireproof wall, 2... Painted object (automobile body), 3... Conveyor rail, 4...
... Conveyor =, 5... Suction duct, 6...
...Blowout duct, 7...Blowout outlet, 8,10.
...Low temperature active catalyst, 9...Suction port, 13
...Truck, 14...Rail, 15...
...Suction duct, 16 ...Blowout duct, 17
...Blowout port, 18.20...Low temperature activated catalyst, 19...Suction port.

Claims (1)

[Claims] 1. A fireproof wall that surrounds the top, bottom, left and right, entrances and exits for painted objects located at both ends of the fireproof wall in the longitudinal direction, conveyance equipment that continuously transports the painted objects from the entrance to the exit, and a fireproof wall that surrounds the fireproof wall in the longitudinal direction. a suction duct provided along the longitudinal direction of the refractory wall and having an inlet for sucking in a part of the air inside the furnace and introducing it into the outside duct; a blow-off duct which has blow-off ports arranged and blows out hot air from a duct outside the furnace into the furnace through the blow-off ports; A paint drying and baking furnace characterized by having a low-temperature active catalyst installed on either side.