JPH11188302A - Drying oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve quality of coating and to reduce time and labor required for cleaning work for a drying oven by removing dust accumulated in the oven. SOLUTION: A base 7 running on a conveyer rail 6 laid under the floor out of an oven and a trestle 4 on which a work W is placed are formed separately up and down through a support 8 with a required height and the support 8 is passed through a slit 9 formed in the floor wall 3F of the drying oven 1 into the oven to move the work W in the oven and to dry it. In addition, when the floor face 3f is cleaned and a cleaning liq. is let to flow on the floor face 3f, the cleaning liq. flows down on the floor face 3f formed on an inclined face toward the slit 9 and while it washes dust accumulated on the floor face 3f away, it flows into dust recovery channels 16 and then, it is drained outside. Therefore, before the dust made to fall on the floor face 3f grows to such a size that generates failure of coating, the dust can be simply removed only by letting the cleaning liq. flow and quality of the coating can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel type drying furnace for drying a work while conveying it by a conveyor,
Particularly, it is suitable for use in a coating drying furnace for drying a coating film.

[0002]

2. Description of the Related Art In a coating line for an automobile body or the like, an automobile body as an object to be coated is placed on a conveyor trolley to carry the coating while being conveyed. We carry in and bake and dry the coating film. In this way, if the entire carriage is carried into the drying furnace, it is possible to continuously apply and dry the article while transporting the article without the trouble of replacing the article on the way.

[0003] In this case, a truck of a conveyor for transporting an article to be coated enters the furnace from outside the furnace and travels out of the furnace again. During the operation of the drying furnace, the carts at room temperature are successively provided. Heat is taken in and the heat inside the furnace is taken out, and the heat is taken out of the furnace. As a result, the heat efficiency is reduced and the running cost is increased. Moreover, not only is the dust attached to the truck easy to be brought into the furnace while traveling outside the furnace, but also the mechanically movable parts such as the rollers and drive mechanism of the truck are arranged inside the furnace, Dust is likely to be generated inside.

[0004] For this reason, the present applicant has proposed a drying oven in which a mechanically movable portion of a conveyor for transporting a workpiece is disposed outside the oven (see Japanese Patent Application Laid-Open No. 8-155372). In this conveyor, a base on which a work is placed and a base running on the conveyor rail are formed vertically separated via a support having a required height, and the conveyor rail is laid under a furnace outer floor, and the support is provided. Is penetrated into a furnace through a slit formed in a floor wall of a drying furnace so that a workpiece placed on the gantry can be moved in the furnace. With this configuration, since there is no mechanically movable part of the conveyor in the furnace, the heat efficiency is excellent, and no dust is brought in or generated by the mechanically movable part.

[0005]

By the way, even if the mechanically movable part of the conveyor is arranged outside the furnace as described above, the drying furnace is provided with entrances for taking in and out the work at both ends thereof. When passing through an entrance or the like, fine dust contained in the outside air is brought into the furnace together with the outside air. The hot air blown into the drying furnace is clean because it passes through a purifying device such as a filter, but extremely small dust that cannot be removed by the purifying device is brought into the furnace.

[0006] Since these dusts are extremely minute, they do not adversely affect the coating film even if they adhere directly to the coating film, but they repeatedly fly up into the furnace or fall down to the floor. In the meantime, dust becomes a nucleus and organic solvent components contained in the furnace air agglomerate on the surface, and they adhere to each other, coarsen, and gradually grow to a size that adversely affects the coating film. .

[0007] In recent years, in both the radiant heating zone (dark red zone) installed in the front stage of the furnace and the convection heating zone installed in the subsequent stage, hot air is vigorously directed toward the lower surface of the work that is difficult to dry. Some types have a hot-air blowing nozzle that blows out.When dried in this type of drying furnace, large dust that does not fly up in a normal drying furnace will fly up, and this will adhere to the coating film surface and cause coating failure. was there.

For this reason, in order to prevent the occurrence of coating defects, the inside of the furnace must be frequently cleaned. In this cleaning work, for example, after the operation of the drying furnace is stopped, fine mist water or alkaline water is sprayed to moisten the floor surface, and then the worker wipes the floor with a mop or a rag. He was doing primitive work and was very laborious and tedious.

Accordingly, the present invention can prevent dust from growing in the furnace to such a size as to cause poor painting, and therefore, can cause poor painting due to dust adhering to the coating film. Instead, it is a technical task to improve the coating quality and to reduce the labor and trouble required for the cleaning operation of the drying furnace.

[0010]

In order to solve this problem, the present invention provides a conveyor for conveying a work, which is disposed along a tunnel-type furnace body, wherein the conveyor has a gantry on which the work is placed. Is attached to a base running on a conveyor rail laid under the floor of the furnace body via a column having a required height, and the column is formed through a slit formed in a floor wall of the furnace body along the transport direction. In a drying furnace which is configured to move a workpiece placed on the gantry through the furnace in the furnace, the furnace body has a floor surface formed on an inclined surface having a downward slope from both left and right sides toward the slit. Dust collecting grooves are provided in parallel on both left and right edges of the opening of the floor wall forming the slit to collect dust dropped on the floor surface together with the cleaning liquid flowing down the floor surface.

According to the present invention, for example, when water or alkaline water cleaning liquid is allowed to flow on the floor of the drying furnace in a state in which the operation of the drying furnace is stopped, the cleaning liquid is inclined downward from both the left and right sides toward the central slit. It flows along the floor formed on the inclined surface toward the slit. Since the dust collecting grooves are provided on both left and right edges of the floor wall forming the slit, the flowing cleaning liquid does not flow out of the furnace from the slit but flows into the dust collecting groove. Therefore, before the dust accumulates on the floor surface of the drying furnace and becomes coarse, only the cleaning liquid is allowed to flow on the floor surface, and the dust collected on the floor surface flows into the dust collecting groove together with the cleaning liquid, making cleaning work easy. To end.

At this time, along the left and right side walls of the furnace body,
If a cleaning liquid supply facility for flowing the cleaning liquid is provided on the floor surface, it is sufficient to make the cleaning liquid flow out of the cleaning liquid supply facility,
It is not necessary for the operator to flow the cleaning liquid to the floor with a hose or the like. Further, since the cleaning liquid is collected in the dust collecting groove, the mechanically movable part of the conveyor such as the drive chain disposed below the slit is not flooded.

[0013] Furthermore, the dust collection groove may be configured such that an opening edge on the floor surface side of the upper surface opening is formed at a height equal to or lower than the floor surface and an opening edge on the slit side is formed higher than the floor surface height. Even if the gas flows vigorously on the floor surface, the opening edge on the slit side blocks the flow, so that it can be reliably poured into the dust collecting groove. Furthermore, a hot air blowing nozzle arranged near the floor surface of the left and right side walls of the furnace body forms an airflow from the left and right sides thereof to the slits along the floor surface, from a discharge pipe connected to the dust collection groove. If the air is exhausted, dust falling on the floor can be dropped into the dust collecting groove as needed while operating the drying oven.

[0014]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a front view showing an example of a drying furnace according to the present invention, FIG. 2 is a front view showing a dust collecting groove, and FIGS. 3 and 4 are a front view and a plan view showing another example of a dust collecting groove. For convenience of description, in FIG. 1, the right side of the center line is a radiant heating zone for drying the work by radiant heat, and the left side is a convective heating zone for drying the work by convective heat.

The drying furnace 1 of the present embodiment is formed in a tunnel type for drying a work W such as an automobile body while being conveyed by a conveyor 2, and a radiant heating zone 1A is formed in a preceding stage thereof, and convection heating is performed in a subsequent stage thereof. Zone 1B is formed. In order to heat the inside of the furnace, hot air circulation ducts 10 for circulating heated air at about 220 to 230 ° C. and radiating radiant heat are provided on both left and right sides of the radiant heating zone 1A.
Are disposed on both sides of the convection heating zone 1B.
A hot air blowing duct 11 for blowing out heated air at about 0 ° C. is provided.

In the conveyor 2, a gantry 4 on which a workpiece W is placed is driven by a drive chain C or the like along a furnace main body 3 on a conveyor rail 6 laid on a conveyor pit 5 formed below the floor. The support 8 is attached to the base 7 via a support column 8 having a required height, and the support column 8 is configured to travel along the transport direction while penetrating the furnace through a slit 9 formed in the floor wall 3F. I have. Therefore, when the workpiece W is placed on the gantry 4 and the conveyor 2 is run, the base 7 travels in the conveyor pit 5 outside the furnace, and the work W placed on the gantry 4 is transported in the furnace. In addition,
The conveyor pit 5 is a groove-shaped space formed under the floor of the furnace main body 3 for arranging the conveyor rail 6 and its drive chain C, and as shown in FIG. When building at a position higher than the installation surface G, the floor wall 3
In addition to the case where the floor wall 3F of the drying furnace 1 is constructed at the same height as the installation surface G, the installation surface G may be formed by excavation.

The furnace body 3 has a ceiling wall 3U, left and right side walls 3L, 3R, and a floor wall 3F formed in a heat insulating structure, and a floor surface 3f.
Are formed on a downwardly inclined surface facing the slit 9 from both left and right sides. In the vicinity of the floor surface 3f of the left and right side walls 3L and 3R, a hot air blowing nozzle 12 for forming an airflow from both right and left sides toward the center slit 9 along the floor surface 3f to dry the lower surface of the work W is provided. Openings are formed at predetermined intervals in each of the ducts 10 and 11 along the longitudinal direction of the furnace main body 3, and a cleaning liquid supply pipe (cleaning liquid supply equipment) 13 for flowing water, alkaline water, and other cleaning liquids down the floor 3f is provided. Have been. The cleaning liquid supply pipe 13 is provided on the floor 3f.
The cleaning liquid may be sprayed toward the left and right side walls as necessary.

In addition, in front of the hot air blowing nozzle 12,
A diffuser 14 is provided, and an ejector 15 is formed by the nozzle 12 and the diffuser 14.
When the hot air blown from the nozzle passes through the throat portion of the diffuser 14, the surrounding air is sucked in, and the air is blown at a flow rate larger than the flow rate blown out from the nozzle 12.

Dust collecting grooves 16 for collecting dust collected on the floor 3f together with a cleaning liquid or an airflow flowing down the floor 3f are provided on both left and right edges of the opening of the floor wall 3F forming the slit 9. They are arranged in parallel. The upper surface opening 17 of the dust collecting groove 16 has an opening edge 17f on the floor surface 3f side equal to or lower than the height of the floor surface 3f and an opening edge 17s on the slit 9 side.
Are formed higher than the height of the floor surface 3f to form a weir.

The dust collection groove 16 is connected to a discharge pipe 18 that sucks and discharges dust along with a cleaning liquid or an air flow flowing down from the cleaning liquid supply pipe 13 along the floor surface 3f. A drain pipe 19 for sucking and discharging the cleaning liquid;
It is branched to an exhaust pipe 20 for sucking air. And
The drainage pipe 19 includes a suction pump 21 that sucks the cleaning liquid that has flowed into the dust collecting groove 16 at a suction amount substantially equal to the flow rate of the cleaning liquid supplied to the cleaning liquid supply pipe 13, and the drainage pipe that is not in use. A valve 22 for closing 19 is interposed. The exhaust pipe 20 has an exhaust fan 23 that sucks dust together with an airflow flowing along the inclination of the floor 3f, a damper 24 that closes the exhaust pipe 23 when not in use, and a filter 2 that
5 are interposed.

The above is an example of the configuration of the present invention, and its operation will be described below. First, hot air is supplied to the hot air circulation duct 10 of the radiant heating zone 1A and the hot air blowing duct 11 of the convection heating zone 1B to start the drying furnace 1, and then,
When the conveyor 2 is started and the work W is transported, the work W is blown out mainly by the radiant heat of the hot air circulation duct 10 when passing through the radiant heating zone 1A and into the furnace when passing through the convective heating zone 1B. It is heated and dried by hot air.

At the same time, each zone 1A, 1
Hot air blow-out nozzle 1 disposed on left and right side walls 3L, 3R of B
Hot air is blown out of the work 2 to form an airflow from both left and right sides to the center slit 9 along the floor 3f, and the lower surface of the work W is dried. At this time, while the outside air flowing in from the entrance and exit of the drying furnace 1 and the minute dust contained in the hot air blown into the drying furnace 1 are flying in the furnace, the organic solvent contained in the air in the furnace is formed on the surface thereof. The components agglomerate and stick together to coarsen. Then, when it falls on the floor 3f in the furnace by its own weight, it is blown toward the slit 9 by the air flow formed by the hot air blowing nozzle 12. Here, if the exhaust fan 23 interposed in the exhaust pipe 20 is operated, the dust moves smoothly on the floor 3 f formed on the downward slope toward the slit 9 and the dust collection groove 16 is formed. And is discharged to the outside through the discharge pipe 18 and the exhaust pipe 20 communicating therewith. Accordingly, since the air in the furnace is kept clean, coating defects are reduced, and the coating quality can be further improved. In addition, since dirt in the furnace is reduced, it is not necessary to frequently perform a cleaning operation. In particular, when inspecting the inside of the drying furnace 1 which has been performed about once every two to three weeks, it is not necessary to completely clean the ceiling surface, the left and right side wall surfaces and the floor surface 3f. Sufficiently, it is sufficient to perform the entire cleaning about once every two to three months, so that the labor required for the cleaning operation can be significantly reduced.

When the entire cleaning is performed once every two to three months, the cleaning liquid is caused to flow out of the cleaning liquid supply pipe 13 and the drain pipe 19 while the operation of the drying furnace 1 is stopped.
Is operated with the same drainage capacity as the supply amount of the cleaning liquid. Since the floor surface 3f is formed as a downwardly sloping surface facing the slit 9 from both the left and right sides, the cleaning liquid flows down the floor surface 3f and pushes dust accumulated on the floor surface 3f while collecting dust in front of the slit 9. The dust that flows into the groove 16 and accumulates on the floor 3f is not sowed in the furnace and is discharged together with the cleaning liquid into the drain pipe 18 and the drain pipe 1.
Exhaust via 9. As described above, even in the entire cleaning operation performed about once every two to three months, the floor surface 3f can clean and remove the accumulated dust only by flowing down the cleaning liquid. Cleaning only the classes is sufficient, and the labor is significantly reduced.

At this time, since the cleaning liquid flows into the dust collecting groove 16 before flowing into the slit 9, the cleaning liquid does not overflow in a large amount as long as the splash is scattered to the outside from the slit 9. Also, as in this example, the dust collection groove 1
By forming the opening edge 17s on the side of the slit 9 on the side of the slit 9 higher than the floor 3f, the flow rate of the cleaning liquid flowing down the floor 3f is increased, and even when the cleaning liquid flows vigorously toward the slit 9, the dust collecting groove 16 is formed. Is reliably blocked by the opening edge 17s, so that it never overflows from the slit 9 to the conveyor 2 disposed therebelow. As described above, in this example, dust can be removed only by flowing the cleaning liquid, and the conveyor 2 does not get wet.

FIGS. 3 and 4 show a front view and a plan view of another example of the dust collecting groove 16. In this example, the dust collecting groove 16 can be opened and closed at the opening edge 17 s of the dust collecting groove 16 facing the slit 9. Pair of flaps 30R, 30L are hinges 31, 31
Attached through. And flap 30
As shown in FIG. 3, R and 30L abut each other in a mountain shape when viewed from the front with the tip 32 abutted and closed. Further, as shown in FIG. 4, the approach side edges 33R, 33L into which the support 8 enters between the flaps 30R, 30L advance from the base 34 toward the tip 32 as viewed from the upper surface thereof. It is formed to be inclined in the direction. Therefore, when the strut 8 enters while the flaps 30R, 30L are closed, the strut 8 is moved into the entry-side edges 33R, 3R.
Since each of the flaps 30R and 30L is automatically opened because the 3L is moved while being pushed and spread horizontally. When the support 8 has passed, the flaps 30R and 30L are automatically closed by their own weight or by the elasticity of a spring (not shown). The flaps 30R, 30L may be formed of a rubber plate, a resin plate, or the like, and the roots thereof may be fixed to the opening edge 17s of the dust collecting groove 16. In this case, each of the flaps 30R and 30L is bent and pushed open as the support 8 passes, and when the support 8 has passed, each of the flaps 30R and 30L is opened.
R, 30L closes automatically due to its elasticity.

As described above, in this example, if the support 8 does not pass, the flaps 30R and 30L do not open and the slit 9
Is closed, the dust dropped into the dust collecting groove 16 by the cleaning liquid or the air flow passes through the slit 9 and is mechanically movable on the conveyor 2 such as the drive chain C disposed therebelow. Without falling to
Intrusion of outside air and leakage of air in the furnace can be suppressed as much as possible, so that the thermal efficiency in the furnace does not decrease.

In the above description, the case where the cleaning liquid supply pipe 13 is disposed in the furnace and the cleaning liquid automatically flows down to the floor 3f has been described. However, it is needless to say that the cleaning liquid hose or the like having a nozzle at the tip is used. The cleaning liquid may be caused to flow down to the floor 3f by the worker spraying water.

[0028]

As described above, according to the present invention, the dust dropped on the floor can be poured into the dust collecting groove together with the cleaning liquid, so that the labor required for cleaning the floor is significantly reduced. Before the dust falling on the floor of the drying oven grows to a size that causes poor painting,
By cleaning the floor surface, dust can be easily discharged to the outside of the furnace, so that coating defects due to dust adhering to the coating film do not occur and coating quality can be improved. It works.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of a drying furnace according to the present invention.

FIG. 2 is a front view showing a dust collection groove.

FIG. 3 is a front view showing another example of the dust collecting groove.

FIG. 4 is a plan view thereof.

[Explanation of symbols]

 1 ... Drying furnace W ... Work 2 ... Conveyor 3 ... Furnace body 3F ... Floor wall 3f ... Floor surface 4 ... Stand 6 ... Conveyor rail 7 ... Base 8 ... Prop

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F26B 15/16 F26B 15/16

Claims (4)

[Claims] A conveyor (2) for transporting a work (W).
Is disposed along a tunnel-type furnace body (3), and the conveyor (2) includes a gantry (4) on which a workpiece (W) is placed.
Is mounted on a base (7) running on a conveyor rail (6) laid under the floor of the furnace body (3), and a support (8) having a required height.
And the support (8) is penetrated through the furnace body (3) from the slit (9) formed in the floor wall (3F) of the furnace body (3) along the transport direction thereof, and In the drying furnace in which the work (W) placed on (4) is moved in the furnace, the furnace body (3) has a floor surface (3f) descending from both left and right sides toward the slit (9). The cleaning liquid flowing down the floor (3f) along the left and right edges of the opening of the floor wall (3F) formed on the slope and forming the slit (9) flows down the floor (3f). A drying furnace, wherein dust collecting grooves (16) for collecting the dust are arranged in parallel. 2. A top opening (17) of a dust collecting groove (16).
Means that the opening edge (17f) on the floor (3f) side is formed to be less than the height of the floor surface (3f) and the opening edge on the slit (9) side
(1) wherein the (17s) is formed higher than the height of the floor (3f).
Drying furnace as described. 3. A cleaning liquid supply system for flowing a cleaning liquid to a floor surface (3f) along left and right side walls (3L, 3R) of a furnace body (3).
The drying furnace according to claim 1 or 2, wherein a drying oven is provided. 4. Air flowing toward the slit (9) from both right and left sides along the floor (3f) near the floor (3f) on the left and right side walls (3L, 3R) of the furnace body (3). A hot air blowing nozzle (12) for forming a flow is provided, and the dust collecting groove (1
The drying furnace according to any one of claims 1 to 3, wherein a discharge pipe (18) for discharging dust accumulated in the groove (16) to the outside is connected to (6).