JPS5849467A - Method and device for continuous drying and baking - Google Patents

Abstract

PURPOSE:To improve heat transfer ability and to shorten a treatment time by providing a heating stage independently between a drying stage and a baking stage, and heating a metallic strip while conveying the same by a floating system in the heating stage. CONSTITUTION:In the stage of drying and baking a metallic strip 4 which is coated with prescribed paint continuously by heating the same while running the strip without contact, a heating stage 10 which heats the strip 4 quickly up to the temp. at which forming components for paint films can be polymerized after evaporation of solvents is provided independently between a drying stage 8 wherein the solvents are evaporated from the paint coated on the strip 4 and a baking stage 12 wherein the prescribed paint films are formed on the surfaces of the strip 4 by polymerizing the forming components for paint films in the paint. In said stage 10, the strip 4 is heated while the same is conveyed by a floating system, whereby the heat transfer ability to the strip 4 is increased, the treatment time is reduced and the baking is homogenized.

Description

[Detailed description of the invention] The heather invention is 1! I! Continuous drying anti-seizing relates to a method and apparatus n.
11 of the new local float force type that takes the length 1't of the catenary method and the float method to 'kt' and adds 1 + person! Subsequent drying and baking relates to methods and apparatus.

Conventionally, continuous dry baking, in which the mating strip is moved downward without contact and heated with hot air to dry and glare the paint, has been carried out using either the catenary (fl feed) method or the float method.
(, γ-lift conveyance) method has been used.

Among them, in the catenary method, there is nothing to correct the distance between the metal strip and the hot air jet nozzle, so if suspended conveyance is performed over a long span, the metal strip will fall or twist, and the metal strip The distance between the nozzle and the nozzle will vary. However, the tendency for collapse (twisting) to occur increases as the suspension span becomes longer, and is more pronounced in the center of the catenary curve than near both ends. Therefore, in order to prevent insects from contacting the metal strip and the hot air jet nozzle, a distance that is at least twice as long (approximately 200 M) is provided between the metal strip and the hot air nozzle as in the case of the float method. Therefore, the catenary and hollow methods have the drawbacks of low heat transfer ability and non-uniform baking.

On the other hand, in the F0-) method, the shortcomings of the catenary method are turned into advantages, as the conveyance stability is improved and the distance between the metal strip and the nozzle can be shortened, so the heat transfer ability is improved. It has advantages such as high cost and uniform baking. However, if the weight of the gold maple strip is heavy and the heating temperature of the strip is low, more hot air than that for heating is required for the lifting force, and therefore a large fan power is required. Even if hot air is within an allowable temperature range that does not adversely affect the strip, if it is blown at that temperature, the temperature of the strip will rise too much, so the heat and temperature must be lowered. When operating a machine like Jin's, a device is required to control not only the volume of hot air but also the altitude of the hot air. This means that as the temperature tx difference between the strip and the hot air decreases, the blowing speed of the hot air decreases and the heat conduction decreases, and the fan power is required by that amount (U+).

The purpose of Mokuko Tll'i is to provide a novel continuous dry baking method and apparatus that incorporates the advantages of the prevapicatenary method and the float method. The metal strip coated with the paint is heated while running under non-contact conditions, and is continuously dried and baked. After the solvent evaporates, the film-forming components are polymerized between the step and the main baking step, where the coating film-forming components in the preparation are weighed to form a prescribed coating film on the IJ tube surface. A temperature raising step for rapidly heating the metal maple strip to the desired temperature is provided independently, and in the temperature raising step, the metal strip is heated while being conveyed by a float system.

Further, as an apparatus suitable for implementing such a method, the present invention provides an apparatus for heating a metal strip coated with a predetermined paint while running it in a non-contact state, and continuously drying and baking it. A drying zone, a temperature raising zone, and an attached belt are provided in the heat treatment furnace where such drying and baking are performed, and the drying zone includes a first heating mechanism that heats the metal strip that is conveyed in a suspended state. a second heating mechanism that heats the metal strip while conveying it in a float manner in the temperature increasing zone; and a second heating mechanism that heats the metal strip while conveying it in a suspended state in the baking zone; The third heating mechanism is located to the left of each arrangement. .

Thus, according to the present invention, the IJ tube can be held constant and reliably by the float method or the central vinegar 7 minute (Jul) in the furnace, where the IJ knob is significantly bent (twisted). , the furnace is divided into both parts (drying to flattening and baking band) and small snozen, which effectively suppresses fluctuations in the metal strip, and the feature of the float system in the middle part makes it possible to separate the metal strip and It is possible to shorten the distance between nozzles as much as possible, and due to drying, heat transfer f? While the force is improved and the baking becomes more uniform, it requires only 7 amps of power compared to the conventional all-float system, and it is easier to control the air volume. A heating process based on a new consideration that divides the two processes of drying and baking into eight processes of drying, heating, and baking, allows large quantities of α
By skillfully utilizing the characteristics of the floating heating method, the metal strip is rapidly heated to a temperature that can polymerize the film-forming components, and the baking process extends the strip boiling time in the process. This also has the effect of completing the polymerization reaction and achieving complete baking.

In the following, the continuous dry baking according to the invention will be explained in more detail with reference to the drawings showing a suitable apparatus for carrying out the method.

First, in FIG. 1, reference numeral 2 denotes a continuous drying/baking furnace that dries and bakes paint while running a metal strip 4. Inside the furnace shell 6, there is a drying zone 8 at the front and a raised area at the middle. A band 10 and a band 12 are provided at the rear.

Then, in the drying zone 8 and the baking zone 12, the metal strip 4, which is conveyed in a suspended state, is heated by jetting hot air from a large number of jetting nozzles provided in the inner chamber 7 and the lower chamber 9. The first heating mechanism 11 and the eighth heating mechanism 15F are different from each other by 10±,
Also, the temperature in the middle part increases.

The belt 10 is conveyed by a float method:
A second heating mechanism 18 is provided which floats and heats the group metal strip 4 by jetting hot air from the upper floater 14 and the lower floater 16.

On the other hand, in front of the entrance 20 of the furnace shell 6 is a guide roller 22.2.
4 and coating coaters 26 and 28 are installed, and the outlet 30 of the furnace shell 6 is equipped with a cooler (forced air cooling device) 32 for strip cooling, a guide port 4 34, and a water cooling chamber 36 using water injection. Furthermore, a ringer roll 88 for dewatering, a drying device 40, and guide rollers 42, 44, 46 are provided.
are arranged sequentially.

By the way, such upper and lower parts 70-ta 14 and 1
6 (■Various formats may be applied, but the patent application filed by the same applicant as the present invention, 1986-1986)
Taking No. 2 as an example, the upper floater 14 has a configuration in which a large number of hot air jet nozzle holes are arranged in a staggered manner, and the lower floater 16 has a large number of hot air jet nozzle holes that are arranged continuously in the running direction of the strip. A configuration is adopted in which they are arranged in a rhombus shape and in a plurality of rows on each side of the rhombus shape.

For example, in another device published by the same applicant (Japanese Patent Application No. 56-121749), the lower floater 16 has a hole-shaped or slit-shaped ejection nozzle that is continuous in the running direction of the strip. The jet nozzles are arranged in a rhombus shape and arranged in rows on each side of the rhombus shape, and extend upward from the outer side of the rows of jet nozzles forming the rhombus shape for a predetermined distance. A configuration may also be adopted in which a piece-shaped wind guide plate is provided to cover the upper part of the ejection nozzle, and the gas ejected from the ejection nozzle is guided to the center side of the rhombic shape by the wind guide plate. It is.

Furthermore, if we take the known floater shown in FIG. 2 as an example,
Consisting of a pair of static pressure pads 50 made of hollow rectangular cylinders extending in the width direction of the metal strip 4, and velocity pressure tubes 60 arranged alternately with the static pressure pads 50 in the longitudinal direction of the strip 4. The static pressure pad 50 is
As shown in the figure, a pair of inwardly inclined slits 62 are provided on the surface facing the IJ tab 4. The hot air blown out from this slit 52 creates a static pressure area 54 between the metal base strip 4 and both slits 52.
is formed. In addition, several velocity pressure nozzles 62 are formed on the surface of the velocity pressure tube 6LO facing the metal IJ tube 4, and the gold strip 4 is heated by the hot air jetted from these velocity pressure nozzles 62. It is.

In this way, in any type of floater, a static pressure region is formed by the ejected gas, and the metal strip 4 is stably transported in a floating state.

In the continuous dry baking oven configured in this way, the metal strip 4 is guided by guide rollers 22, 24, coated with a predetermined paint by coaters 26, 28, and then guided into the oven shell 6.

The strip 4 is heated to approximately 100°C by the hot air blown from both chambers 7 and 9 in a suspended state in the dry calving chamber 8.
The temperature is raised to a certain temperature, and the bath agent in the applied paint is evaporated. Next, in the temperature rising zone lO, the strip 4 is
is stably suspended almost horizontally, and rapidly heated by a large amount of hot air jetted out to a temperature (approximately 200° C.) at which the coating film-forming components can be polymerized.

Further, the baking is carried out in the band 12 while running in a suspended state at approximately -280°C in order to complete the polymerization reaction.
It is kept at °C for a predetermined period of time. In addition, from the viewpoint of the influence on the paint film, blowing is preferable in the drying zone 8 where the paint has fluidity, and it is desirable to treat with strong wind in the temperature rising zone 10 where the paint has lost its fluidity after drying. However, for dry baking with such a configuration, the oven is capable of such operation.

After being dried and baked in the furnace shell 6 in this way, the metal strip 4 is guided to the outside from the outlet 3° of the furnace shell, cooled with forced air by the cooler 32, and changed direction by the guide roller 34. It will be done. And metals) IJ knob 4
is further cooled by water jet in a water cooling chamber 86, dehydrated by a ringer roll 38, dried in a drying device 4o, passed through guide rollers 42, 44, 46, and wound up as a product. It has become.

In this way, the metal strip 4 is connected to the guide rollers 28 and 34.
As the metal strip 4- is suspended in a catenary curve inside the fried rice 6, only the central part is suspended and supported in a horizontal state, so that the catenary part of the metal strip 4- is partitioned into two short and small snowboards. The shortcoming of the catenary system, which is the lack of transport stability, is improved, while the shortcoming of low heating capacity does not pose a major problem in the drying zone 8 and the burning problem in the zone 12. Incidentally, a small heating capacity in the temperature rising zone 10 is a big problem, but in the present invention, the strip 4 is conveyed by a float system for 10 seconds in the temperature rising zone 10, so a large heating capacity can be generated. be.

Further, as shown in FIG. 4, if the metal strip 4, which is held between the upper and lower floaters 14 and 16 and maintained in a floating state, is bent or twisted, the action of the static pressure region Since the force is inversely proportional to the square of the distance between the metal strip 4 and the floater 14 or 16, the wind pressure distribution changes according to the twist, and the metal strip 4 is automatically returned to the state shown in FIG. 5 immediately. Therefore, the metal strip can run extremely stably at all times.

Furthermore, if the entire furnace is of the catenary type, the central part of the furnace (heating zone) where the metal strips are significantly collapsed,
In order to be stably and reliably held by the float method, the metal strip 4 is attached to the upper or lower floater 14.
The risk of contacting the floaters 14 and 16 resulting in defective products is completely eliminated, and the distance between the metal strip 4 and both floaters 14 and 16 can be shortened as much as possible, for example, close to 40 to 4tto=. Therefore, the impingement speed of the hot air on the metal strip 4 increases, the heat transfer capacity increases, the processing time is shortened, and the baking becomes more homogeneous.Furthermore, continuous dry baking increases the conveyance speed of the device or the furnace. Since it is also possible to shorten the length, it has excellent effects on energy saving and cost reduction.

In the above embodiments, the series of drying and baking as shown in FIG. may be arranged in a continuous manner.

In addition, an upper chamber 7 as a first and third heating mechanism,
It is assumed that the lower chamber 9 is heated by ejecting hot air from a large number of ejection nozzles provided therein, and the three types of floaters described in 0f1 are illustrated as examples of the second heating mechanism, but other known methods are used. It's a formal power 11 heat mechanism, so there's no point in insulting it.

It goes without saying that other modifications and improvements can be made to the present invention based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional explanatory view of an apparatus suitable for carrying out the continuous drying and baking method according to the present invention, and FIG. 2 shows the upper part of the apparatus,
Section IK1 showing an example of the lower floater 14.16, No. 8
The figure is an enlarged cross-sectional view of the static pressure pad 50, FIG. 4 is a schematic cross-sectional view in the strip width direction showing the twisted state of the IJ knob 4, and FIG. . 2: Furnace for continuous dry baking 4: Metal strip 7: Upper chamber 9: Lower chamber 8: Drying zone
lo: Temperature raising zone 11: First heating mechanism 12: Baking zone 13: Second heating mechanism 15: Third heating mechanism 14: Upper floater
16; Lower floater 50: Static pressure pad Applicant: Daido Steel Co., Ltd.

Claims (2)

[Claims] (1) Metallic surface coated with a specified paint) Continuously heat the IJ tube while running it under non-contact conditions. In drying and baking, there are two steps: a drying step to evaporate the solvent from the paint applied to the metal strip, and a baking step to polymerize the film-forming components in the paint to form a predetermined paint film on the surface of the strip. After the solvent evaporates during
(the metal layer) up to a flow rate that allows the coating film-forming components to be polymerized)
A continuous dry baking method characterized in that a temperature raising step for rapidly heating the IJ tube is provided independently, and in the temperature raising step, the metal strip is heated while being conveyed by a float method. 0 (2) The metal base coated with the specified paint) The IJ tube is heated while running under non-contact conditions, and is continuously dried.
In the baking equipment, a drying zone, a heating zone, and a baking zone are provided in the heat treatment furnace in which the drying and baking are carried out, and the drying and recording zone is provided with the metal strip which is conveyed in a suspended state. The first heating bar is heated by plowing and heating, the second heating +1 is placed in the lifting zone to heat the gold strip while conveying it by a float method, and the baking is carried out by heating. The continuous dry baking system is characterized in that a third heating mechanism is respectively arranged to heat the metal strip being fed in a suspended state.