JPS634875A - Drying furnace for painting - Google Patents

Abstract

PURPOSE:To attain good drying quality and to conserve heat energy by covering the flame from a heater provided in a circulation duct with a cylindrical body having air permeability and averting the direct contact of the solvent-component contained in circulating air with the flame. CONSTITUTION:The heater 9 to inject the flame 17 is provided in the circulation duct 7 connected to a drying furnace 1 and the flame 17 is covered by the cylindrical body 18 having the air permeability. The body 18 is further preferably formed of a contact material. More specifically, the direct contact of the solvent-component contained in the circulating air with the flame is averted, by which the material to impair the quality of the drying the painting is not generated; therefore, the drying quality is improved. A large volume of the circulating air is exchanged with the outdoor air in order to clean the circulating air, by which the problem of a large quantity of heat loss generated heretofore is solved. The heat energy is thereby conserved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a paint drying oven for drying the paint after painting the body of an automobile.

(Prior Art) Generally, drying after coating on the body of an automobile or the like is carried out using a drying oven of direct heating type. An example of this type is a drying oven 1 as shown in FIG. The oven body 2 of this drying oven 1 is formed in the shape of a tunnel, and rails 3 are arranged in parallel on the floor surface thereof. On this rail s, a cart 5 carrying a car body 4 as an object to be dried is conveyed to a conveyor 6.
It can be moved by being connected to. A circulation duct 7 is located parallel to the upper part of the furnace body 2 on the outside thereof, and both ends of the circulation duct 7 are open into the furnace body 2 . A hot air generation mechanism is located in the circulation duct 7, and as the hot air generation mechanism,
A burner equipped with a fuel supply path 8 on the upstream side where heated air circulates in the upper part of the circulation duct 7? is installed and burner 9
A supply duct 10 extends to the outside to take in combustion air. Furthermore, a filter 11 and a circulation fan 12 are located at intervals downstream from the burner 9, and a ventilation duct 13 is attached downstream of the circulation fan 12 to adjust the circulating air.

(Problems to be Solved by the Invention) When drying is carried out using the drying oven configured as described above, the circulating air is directly heated by the burner. The evaporating solvent is exposed to the burner flame and its vicinity at high temperatures (50°C).
0 to 1500°C) and undergo thermal decomposition.

This is caused by yellow substances that adhere to the car body and cause yellowing of the paint film,
This causes the generation of curing accelerators that accelerate the curing of the coating film. In particular, high-white yellowing, poor adhesion between the intermediate coat and top coat, and so-called interlayer peeling occur. As a measure to prevent such problems, a large amount of ventilation is carried out to discharge yellow substances and hardening accelerators from the drying oven and lower their concentration. Therefore, a large amount of heat loss is involved.

Therefore, the present invention has been developed as a VC to solve the above-mentioned problems, and by covering the flame from the heating device installed in the circulation duct with a permeable cylinder, the flame contained in the circulating air can be reduced. To provide a paint drying oven which can achieve good drying quality and save thermal energy without producing substances that impair the quality of paint drying by preventing direct contact of a solvent with flame.

(Means for Solving the Problems) A feature of the present invention for achieving the above object is that a heating device for injecting flame into a circulation duct connected to a drying oven is provided, and the flame is made to have air permeability. This is achieved by the cylinder, and preferably the cylinder is made of a catalyst material.

(Function) According to the paint drying oven of the present invention having the above configuration, the solvent contained in the circulating air does not come into direct contact with the flame and high-temperature air of the zero-force heating device, so the paint quality is reduced. Since no damaging substances are generated and the circulating air is heated by contact with the cylinder, the drying quality of the coating is good.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. First, FIG. 1 shows an embodiment of the coating drying oven 1 of the present invention,
It has the same configuration as that already explained in the prior art based on FIG. 3, and the same reference numerals are given to the same parts, and detailed explanation thereof will be omitted. A circulation duct 7 is located in the upper part of the furnace body 2, which is the same as the one shown in FIG. One is an inlet 14 for circulating air, and the other forms an outlet 15 to allow circulation. To explain one embodiment shown in FIG. 1, the circulation duct 7
Inside, a burner 9 is installed as a heating device above the inlet 14, and is connected to the fuel supply path 8 via a control pulp 16. A metal cylindrical body 18 is formed of a porous material having air permeability so as to cover the flame 17 from the burner 9 within the circulation duct 7.
is installed. This metal cylindrical 18Fi container shape is formed by forming a thin ribbon-shaped nickel-chromium alloy metal material into an aggregate and supported by a reinforcing member, or it is made of pellets made of nickel-chromium alloy metal material. It is made into a shape and placed in a net-like structure formed into a cylindrical body.

In this way, the contact area is increased so that the air passing through the wall of the metal cylinder 18 can come into contact with as much of the material forming the metal cylinder 18 as possible. Further, the metal cylinder 18 can be prevented from oxidizing by coating the metal cylinder 18 with ceramics or the like.

Here Fi, the metal cylindrical body 18 formed as described above is doubled to direct the flame 17 of the burner 9. This flame 1
Near where the flame 17 of the burner 9 spouts out at the base end of the burner 7, there is a
A nozzle 19 for introducing outside air is open. The nozzle 19 is located so as to surround the flame 17, and communicates with a supply pipe 20 that passes through the metal cylinder 18 and extends to the outside of the circulation duct 7. The supply pipe 20 is connected to a filter 22 via a blower 21, so that outside air is blown out along the outside of the flame 17 inside the metal cylinder 1″8. Blower 21
When the rotation controller 23 connected to the temperature controller 25, the control pulp 16 for fuel supply, and the temperature sensor 24 attached to the furnace body 2 are electrically connected to the temperature controller 25, the amount of outside air introduced It also adjusts the amount of fuel supplied. The pressure inside the metal cylindrical body 18 is always maintained higher than that outside.

Next, in another embodiment shown in FIG. 2, a double metal cylinder 18 made of the same metal material as above is attached so as to cover the flame 17 from the burner 9. In this example, in order to suck the heated air inside the metal cylindrical body 18, one end of the circulation pipe 26 is placed at the bottom of the metal cylindrical body 18, that is, at the tip of the flame 17, at a location opposite to the opening cross section of the circulation duct 7. is open. The circulation pipe 26Fi protrudes outward from the circulation duct 7, returns to the circulation duct 7 via the blower 27, and is open. A temperature sensor 28 is attached to the circulation pipe 26 in front of the blower 27, and by electrically connecting this to a rotation regulator 29 that controls the rotation speed of the blower 27, the blower 27 is rotated and the metal tube The inside of the body 18 becomes a negative pressure, and the trap is formed so that drying circulating air is forcibly introduced into the metal cylinder body 18.

The metal cylinder 18I/i used here is formed by a catalyst. That is, as described in one embodiment, platinum catalyst powder is attached to a molded metal material, or a spongy platinum catalyst is attached to a metal cylinder using a mesh or other reinforcing member. It is molded into a body 18. Here, platinum was used as a catalyst, but other materials such as palladium can also be used.

Note that the blower 21 for introducing outside air described in one embodiment and the blower 27 for sucking heated air described in the other embodiment rotate in proportion to the combustion amount of the burner 9.

With the above configuration, the circulating air for drying circulates inside the paint drying oven 1. The circulating air that has come into contact with the car body 4, which is the object to be painted, enters the inlet 14 of the circulation duct 7, and the heated air inside the metal cylinder 18 By adding outside air to the cylinder and removing the heated air, the circulating air comes into contact with the metal cylinder 18K and is heated to a predetermined temperature, while the evaporation from the car body 4 contained in the circulating air is Since the solvent does not come into direct contact with the flame and high-temperature air inside the metal cylinder 18, it circulates as circulating air without generating substances that impair drying quality, or the metal cylinder made of a catalyst material. By contacting the body 18 and being combusted and decomposed, the circulating air is sucked by the circulation fan 121C and circulated from the circulation duct 7 into the furnace body 2 without directly coming into contact with the flame. The condition of the circulating air will be explained.

First, in one embodiment shown in FIG. 1, the burner 9 has three
It burns in the range of ~300,000 ken1/H, and this combustion heat is transferred from the inner metal cylinder 18 to the outer metal cylinder 18 with a gap.
can be conveyed to. At this time, the inside and outside (IQ metal cylinder 18
In order to make the temperature distribution as constant as possible, the outside air of α5~5J/rHi (1) is
70 and added to the heated air inside the metal cylinder 18. Due to this, the temperature distributed in the inner metal cylinder 18 is 300 to 600°C, and the temperature distributed in the outer metal cylinder 18 with a gap is 30°C.
0 to 400°C, and the variation J of the temperature distribution becomes small. Therefore, as described above, the circulating air is heated by contacting the metal cylinder 18, and the circulating air in the furnace body 2 is heated by the drying air. A predetermined temperature can be maintained.Here, the inner and outer porous metal cylindrical bodies 18 have a burner combustion air contact surface roughness of about 1700 m''/rr/. In this way, the solvent is prevented from coming into direct contact with the flame and high-temperature air inside the metal cylindrical body 18, thereby preventing the generation of yellow substances and the like. At this time, the inside of the metal cylindrical body 18 is filled with combustion gas and the outside air introduced into the metal cylindrical body 18.
Since the pressure is higher than that outside, the circulating air containing the solvent does not enter into the metal cylinder 18 even if it comes into contact with the metal cylinder 18.

- On the other hand, in another embodiment shown in FIG.
A blower 27 is rotated to cause a portion of the heated air to flow into the circulation pipe 26. By this,
By creating a negative pressure in the metal cylinder 18 compared to the inside of the circulation duct 7, especially near the inlet 14, and forcing the circulating PJI air into contact with the metal cylinder 18 made of outer and inner catalyst materials, Tljl The solvent contained in the air is burned and decomposed into harmless water and carbon dioxide within the layer of the metal cylindrical body 18, and the solvent is kept in direct contact with the flame and high-temperature air. As a result, the circulating air can come into contact with the porous metal cylinder 18 more, resulting in a thermal efficiency of 10,000. Here, the heated air flowing into the circulation pipe 26 is not discharged to the outside, but the metal cylinder 18. It is used temporarily to create a negative pressure in the inside of the duct 18, and the inflowing air is returned to the circulation duct 7 again, so that no heat loss occurs.

Note that in both embodiments [1 and 2] above, the metal cylinder 1B is used in a double layer, but it may be in a single layer or in three or more layers as required.

In addition, although one embodiment and another embodiment have been disclosed separately as a means for adjusting the air within the metal cylinder 18, by providing both together, even better purification and heating of the circulating air can be achieved. It can be achieved.

(Effects of the Invention) From the above, by covering the flame injected from the heating device provided in the paint drying oven of the present invention with a cylindrical body, preferably with a cylindrical body made of a catalyst material, burner flame and high temperature Heat can be efficiently heated by blocking the air and the circulating air and bringing the drying circulating air into contact with the cylinder at a predetermined temperature. At this time, either prevent the outside of the solvent in the circulating air from coming into direct contact with the flame or high-temperature air to prevent the outside of the solvent from deteriorating into substances that impair the quality of the coating, or force the circulating air into the cylinder. By infiltrating and burning and decomposing the outside of the solvent, the outside of the solvent in the circulating air is prevented from coming into direct contact with flames and high-temperature air, making it possible to generate circulating air suitable for drying, resulting in good drying quality. Conventionally, the problem of large heat losses caused by replacing large amounts of circulating air with outside air in order to purify the circulating air can be overcome. This saves thermal energy.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view showing a paint drying oven which is an embodiment of the present invention, FIG. 2 is a schematic longitudinal cross-sectional view showing a paint drying oven which is an embodiment of the pond of the present invention, and FIG. 1 is a schematic vertical sectional view showing a conventional paint drying oven. 1: Drying oven (painting drying oven) 7: Circulation duct 9: Heating equipment fi (burner) 17: Flame 18: Cylinder (metal cylinder)

Claims (2)

[Claims] (1) A paint drying oven characterized in that a heating device for injecting flame is provided in a circulation duct connected to the drying oven, and the flame is further covered with a cylinder having air permeability. (2) The paint drying oven according to claim 1, wherein the cylindrical body is formed of a catalyst material.