JPS6034766A - Coating and drying furnace for resin member - Google Patents

Abstract

PURPOSE:To provide a coating and drying furnace for resin members which requires less heat amt. for elevation of temp., and can prevent insufficient drying of product, by enabling heating by a direct convection heating method in the stage for elevating temp. of the furnace and by an indirect convection heating method in the stage of baking and curing of coated film. CONSTITUTION:At openings of both ends of a drying furnace 1, high-temp. air in the furnace 1 is sucked form an end of a circulation duct 3, 3a by a circulation fan 4, 4a, and air curtain is formed by an air curtain device 2, 2a ejecting high- temp. air downward from another end of the circulation duct preventing thus flowing out of high-temp. air from the opening parts at both ends. During elevation of temp. of the drying furnace 1, elevation of temp. is performed by direct convection heating by which high-temp. air produced by a combustion burner 20 is directly supplied. When the temp. reaches specified temp., the temp. is maintained by the indirect convection heating utilizing a heat exchanger 17. Resin members loaded on a truck are conveyed into a drying furnace 1 at a specified temp. by a conveyor and coated film on the surface or the member is baked.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paint drying oven suitable for baking and curing a paint film formed on the surface of a resin part.

Conventionally, when baking and curing the paint film formed on the surface of urethane resin parts, etc., heat is used via a heat exchanger to prevent drying defects such as wrinkled skin during baking and curing of the paint film. An indirect convection type paint drying oven is used.

The indirect convection type paint drying oven is shown in Figure 3. In FIG. 3, reference numeral 51 denotes a paint drying furnace, and the paint drying furnace 1 has a circulation duct 52a whose both ends open into the inside of the paint drying furnace 1, and a circulation fan installed in the middle of the circulation duct 52a. 52b is provided, and an air supply chamber 53 and an exhaust chamber 54 are formed inside. On the outside of the paint drying oven 1, one end opens to an air supply chamber 53, and the other end opens to an exhaust chamber 5.
A circulation duct 55 is disposed that opens to the 4, and a heat exchanger 56 and a circulation fan 57 are disposed in the middle of the circulation duct 55.
and is provided. Further, the heat exchanger 56 has a structure in which an air supply duct 60 in which a combustion burner 58 and an air supply fan 59 are provided is connected.

However, such an indirect convection type paint drying oven 51
, the high temperature air heated by the combustion burner 58 and the circulating air circulating in the circulation duct 55 are transferred to the heat exchanger 5.
Since the heat exchange is carried out by 6, an extra amount of heat is required to heat the air in each car, and when the temperature rises in the early stages of operation of the paint drying oven 1, that is, when there are no painted resin parts. , even when drying defects never occur.

Since the temperature is raised via the heat exchanger 56, there is a problem that it takes time to raise the temperature.

The present invention was made to solve the above-mentioned problems, and its purpose is to use direct convection heating when increasing the temperature of the drying oven.
A coating drying oven for resin parts that uses indirect convection heating during baking and curing of paint films to reduce the amount of heat during temperature rise and prevents drying defects during baking and curing of resin parts loaded with T1. It is about providing.

The above-mentioned object of the present invention is to provide a drying furnace in which a near car generator is installed at the frontage of two ends, and an air supply chamber and an exhaust chamber are formed inside the drying furnace. Open to the chamber.

A circulation duct is provided whose other end is connected to the exhaust chamber, a heat exchanger and a circulation fan are provided in the middle of the circulation duct, and the heat exchanger is provided with a combustion burner and an air supply fan. A first detour duct connects the downstream side of the air supply fan of the air supply duct and the downstream side of the heat exchanger of the circulation duct, and connects the upstream side of the circulation duct and the upstream side of the air supply duct. are connected by a second detour duct, dampers are provided in each of the circulation duct and the air supply duct on the upstream and downstream sides of the heat exchanger, and the first... Second
This can be achieved by using a coating drying oven for resin parts, which is characterized by providing a damper in each of the detour ducts.

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a longitudinal cross-sectional view of a coating drying furnace for resin parts according to the present invention, and FIG. 2 is a front view taken along the line "T" in FIG. 1. In FIGS. 1 and 2, l is a drying oven formed in the shape of a tunnel and open at both ends, and air curtain devices 2.2a are provided at both ends of the drying oven 10, respectively. ing. This air curtain device 12.
2a is.

It consists of a circulation duct 3.3a whose both ends open into the inside of the drying oven 1, and circulation fans 4, 4a provided in the middle of the circulation ducts 3, 3a.

The air curtain devices 2, 2a are connected to the circulation duct 3.
, 3a, the high-temperature air inside the drying oven 1 is sucked in from one side, and an air curtain is formed from the other side to close the openings at both ends of the drying oven 1.

Further, a conveyor 5 is installed in the center of the drying oven 1 in the longitudinal direction, and this conveyor 5I also has a trolley 6 on which the resin parts W to be dried are placed and transported. There are multiple doguwa to hang on to. Rails 8, 8a are laid on both sides of the conveyor 5, and the cart 6 is guided by the rails 8.8 m.

Further, partition plates 9, 9a are disposed in the lower both sides of the drying oven 1 in the longitudinal direction. This partition plate 9.9m
has a space between it and the side furnace wall Qla, and its upper end is connected to the side furnace wall 1.
It is bent towards the a side.

Its tip is fixed to the side furnace.

The lower end is fixed to the floor 10. And the partition plate 9.9
A plurality of air outlets 11. The space between the partition plates 9, 9a and the side furnace jlla forms a space 12a in the air supply chamber. A partition plate 13 is disposed in the center of the ceiling oven wall 1b in the drying oven 1 in the longitudinal direction, and both ends and side ends of the partition plate 13 are fixed to the ceiling oven wall g1b. And this partition plate 1
A plurality of suction ports 14 are opened at the bottom of 3.
The space formed by the partition plate 13 and the ceiling furnace 111b forms an exhaust chamber 15.

Also, one end of the outside of the drying oven 1 is connected to the air supply chamber, and one end is connected to the air supply chamber.
A circulation duct 16 is provided which opens into the exhaust chamber 2a and whose other end opens into the exhaust chamber 15.

A heat exchanger 17 and a circulation fan 18 are provided in the middle of the circulation duct 16. Further, an air supply duct 19 formed in a loop shape is connected to this heat exchanger 17, and a combustion burner 20 and an air supply fan 21 are provided in the middle of this air supply duct 19. The downstream side of the air supply fan 21 of the air supply duct 19 and the downstream side of the heat exchanger 17 of the circulation duct 16 are connected by a first detour duct 22, and the upstream side of the circulation duct 16 and the downstream side of the heat exchanger 17 of the circulation duct 16 are connected to each other. 19
is connected to the upstream side by a second detour duct 23.

Further, dampers 24 and 24 are provided on the upstream and downstream sides of the heat exchanger 17 of the circulation duct 16 to open and close the passage of the circulation duct 16.
Dampers 24b and 24c are provided on the upstream and downstream sides of the heat exchanger 17 of the air duct 19 to open and close the passage of the air duct 19. Further, dampers 24d and 24e are provided in the middle of each of the first detour duct 22 and the second detour duct 23.

In the coating drying oven for resin parts configured as described above, the openings at both ends of the drying oven 1 suck high-temperature air inside the drying oven 1 from one end of the circulation ducts 3, 3a by the circulation fan 4.4a, High-temperature air is jetted downward from the other end into the drying oven 1 to form an air curtain, and the openings at both ends of the drying oven 1 are closed to prevent the high-temperature air from flowing out.

When the temperature of the drying furnace 1 is raised at the beginning of its operation, the temperature is raised by direct convection heating to which high-temperature air is directly supplied by the combustion burner 20. Namely.

Damper 2 of the first detour duct 22 and the second detour duct 23
4d and 24e are opened, and the circulation duct 16 and air supply f'
) 19 (D dan z<24, 24a, 24b.

24c is closed. In this state, the air supply duct 19 is connected to the second bypass duct 23 and the air supply duct 1.
Through 9, the royal air for heating inside the furnace 1 is supplied to the combustion burner 20 and heated to a predetermined temperature. The heated high-temperature air is passed through the air supply duct 19 by the air supply fan 21 and the circulation fan 18 into the first bypass duct 22. ? The air outlet 11 is connected to the i-ring duct 16 and the air supply chamber through the air outlet 12a. lla
The inside of the drying oven 1 is heated to a predetermined temperature.

However, when the temperature inside the drying oven 1 is raised to a predetermined temperature, the temperature is maintained at the predetermined temperature by indirect convection heating supplied with heated air that has been heat exchanged by the heat exchanger 17. That is, the first detour duct 22 and the second detour duct 2
3 dampers 24d and 24e are closed, and the circulation duct 16
and dampers 24, 24a, 24b, 2 of the air supply duct 19
4c is open. In this state, the air inside the air supply duct 19 is circulated by the air supply fan 21 of the air supply duct 19,
The air is maintained at a predetermined high temperature by the combustion burner 2o and circulated within the air supply duct 19. At the same time, circulation fan 1
Air in the drying oven 1 is drawn in from the exhaust chamber 15 by 8 and passes through the heat exchanger 17 through the circulation duct 16 . At that time, the high-temperature air circulating through the air supply duct 19 exchanges heat and is heated, passes through the circulation duct 16 and the air supply chamber 12.12a, and passes through the air outlet 11. ll
A is supplied into the drying oven 1 and maintained at a predetermined temperature.

Then, it is kept in a drying oven 1 at a predetermined temperature.

The resin part W placed on the trolley 6 is carried in by the conveyor 5, and the paint film formed on the surface of the resin part W is baked and hardened.

As explained above, in the coating drying oven of the present invention,
When the temperature rises in the early stages of operation of the drying oven, the temperature is raised by direct convection heating, which supplies high-temperature air heated by the combustion burner directly into the drying oven, which greatly reduces the amount of heat supplied during temperature rise. This has the effect of shortening the temperature rise time of the drying oven.

In addition, when baking and hardening the paint film formed on the surface of resin parts, the temperature is maintained at a predetermined temperature by indirect convection heating, which supplies heated air that has been heat exchanged with a heat exchanger into the drying oven. Since the.

It has the effect of preventing the occurrence of drying defects such as Chichimiru L during baking hardening of the paint film.

Furthermore, in the present invention, when the temperature of the drying oven is raised, the temperature is raised by direct convection heating by the combustion burner, so it is possible to reduce the capacity of the combustion burner and the heat exchanger, and the fuel, l! This has the effect of reducing energy such as air and equipment costs.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of a coating drying oven for resin parts according to the present invention, Fig. 2 is a front view cut along the line G in Fig. 1, and Fig. 3 is a conventional coating drying oven for resin parts. FIG. 1... Drying oven, la... Side oven wall, 1b... Ceiling oven wall. 2.2a...Air curtain device. 1. , S33 &... Circulation duct.・l, 4 j 4 fi・-Circulation fan. 5...Conveyor, 6...Dolly, 7...Dog. 8.8a...Rail, 9.9a...Partition plate. 10...floor, 11. l1m...Air outlet. 12.12a...Air supply chamber, 13...Partition plate. 14... Suction port, 15... Exhaust chamber. 16... Circulation duct, 17... Heat exchanger. 18...Circulation fan, 19...Air supply duct. 20... Combustion burner, 21... Air supply fan. 22...First detour duct, 23...Second detour duct. 24.24a, 24b, 24c, 24d, 24e...
Dannoku Applicant Toyota Motor Corporation Figure 2

Claims (1)

[Scope of Claims] A drying oven that is provided with an air curtain device at both end openings and has an air supply chamber and an exhaust chamber formed inside, the drying oven having one end opened to the air supply chamber on the outside of the drying oven. A circulation duct whose other end opens into the exhaust chamber is provided, and a heat exchanger and a circulation fan are provided in the middle of the circulation duct. An air supply duct provided with a combustion burner and an air supply fan is connected to this heat exchanger, and the downstream side of the air supply fan of this air supply duct and the downstream side of the heat exchanger of the circulation duct are connected to the first. In addition, the upstream side of the circulation duct and the upstream side of the air supply duct are connected by a second bypass duct, and the circulation duct and the air supply duct are connected to the upstream side and the downstream side of the heat exchanger, respectively. A damper is provided, and the first. A coating drying furnace for resin parts, characterized in that each of the second detour ducts is provided with a damper.