AU600623B1

AU600623B1 - Varnishing furnace

Info

Publication number: AU600623B1
Application number: AU41163/89A
Authority: AU
Inventors: Ching-Shun Wu
Original assignee: CHING SHUN WU
Current assignee: CHING SHUN WU
Priority date: 1989-01-20
Filing date: 1989-09-08
Publication date: 1990-08-16
Anticipated expiration: 2009-09-08
Also published as: DE68904303D1; EP0378731A1; EP0378731B1; ATE84362T1

Abstract

A varnishing furnace (1) utilizing a plurality of near-ultrared radiation bulbs (2) alternatively arranged into a number of rows spaced apart by a distance on one side, both sides, or both sides and bottom of the furnace to form high temperature regions (3) and low temperature regions (4) alternatively disposed so as to increase varnishing quality, reducing working time as well as saving energy.

Description

i 11 6 23--, COMMONWEALTH OF AUSTRALIA Patents Act 1952 CHING-SHUN WU iS do'o. miilt ccnu!ains the amendm';nts made und:r Section ,9 and is correct for printint i Name of Applicant Address of Applicant Actual Inventor Address for Service No. 2, Alley 18, Lane 58, Min Te Road, Tainan, Taiwan, Republic of China CHING-SHUN WU GRANT ADAMS COMPANY, Patent Trade Mark Attorneys, 9th Floor, National Mutual Centre, 144 Edward Street, BRISBANE. QUEENSLAND. 4000

AUSTRALIA.

COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED: "VARNISHING FURNACE" The following statement is a full description of the invention including the best method of performing it known to us.

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TITLE: VARNISHING FURNACE

ABSTRACT

A varnishing furnace utilizing a plurality of near-ultrared radiation bulbs alternatively arranged into a number of rows spaced apart by a distance on one side, both sides, or both sides and bottom of the furnace to form high temperature regions and low temperature regions alternatively disposed so as to increase varnishing quality, reducing working time as well as saving energy.

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_I If TITLE: VARNISHING FURNACE BACKGROUND OF THE INVENTION This invention relates to a varnishing furnace which utilizes specially arranged near-ultrared radiation bulbs to bake a workpiec.

The varnishing furnace on the market generally falls into three categories: tle electric varnishing furna e, the gas varnishing furnace, and the mediumor far-ultrared ,arnishing furnace. HIoweve r, the first two kinds of varnishling furnaces are seldom used due to their poor productivity, insufficient safety and high cost. Then, the medium or far-ultrared furnace, which is provided with mcdium- or far-ultrared radiation bulbs at one or both sides, becomes the most commonly used furnace for baking. Nevertheless, since the mediunm- or far-ultrared ray is rather long in wavelength, the penetration capability thereof is poor. Further, it requires a long period of time to raise the temperature and so it is impossible for them to dry the paint on 20 the workpiece in a short period of time, thereby causing the following drawbacks: 1. Since the temperature rising rate is slow, it is necessary to have a long furnace to as to increase 57T 2

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fF of the baking time hence easily overheating the workpiece and causing the painting to become a layer of so-called ski n.

2. Since the heat penetration capability is poor, the upper and lower layers of the painting will be subject to different temperatures and the solvent in the lower layer of painting and the upper layer of painting will require different periods of time to vaporize thereby forming so-called pin holes or wrinkles on the upper layer of painting on the workpiece.

3. Since the time for baking is rather long, the electricity cost will he increased and the chance for the dust particle to adhere to the surface of the workpiece will become greater.

4. Since the furnaces have a long body, it will be necessary to prepare a large space to accomodate them.

Since the medium- and far-ultrared rays cannot raise the temperature in a short time and have weak penetration capability, it will be difficult to bake the recess of a workpiece.

Anyhow, in case the medium- and far-ultrared radiation bulbs are replaced with near-ultrared radiation ones, the temperature will be raised in a short time but there will be the following two defects at the same time: S3.

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1. .Since -the near-ultrared ray will. provide higher temperature, the paint ing on the workpiecc will be easily overheated.

2. If the baking time is reduced in order to avoid ovrerheating, it is easier to form so-called pin holes or wrinkles on the pain t ing on the workp iecc L- Pl LII SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a varnishing furnace which may obviate and mitigate the above-mentioned drawbacks.

It is the primary object of the present invention to provide a varnishing furnace which can dry the painting on the workpiece in a short time.

It is another object of the present invention to provide a varnishing furnace which may obviate the occurrence of so-called pin hole, wrinkle or dead point on the workpiece during baking.

It is still another object of the present invention to provide a varnishing furnace which may avoid the occurrence of so-called skin.

It is still another object of the present invention to provide a varnishing furnace which has a rather short body in comparison with the conventional.

It is still another object of the present invention to provide a varnishing furnace which is energy-saving.

i. SIt is still another object of the present i invention to provide a varnishing furnace which can reduce the chance of dust particle in the air to adhere to the surface painting of the workpiece.

It is a further object of the present invention to provide a varnishing furnace which can make the painting firmly adhere on the workpiece.

I6 6 I BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiment of the present invention will be described in detail in conjunction with the accompanying drawings wherein like numberals refer to like or similar parts and in which: FIG. 1 is a perspective view, partly broken, of a varnishing furnace according to the preferred embodiment of the present invention; and FIG. 2 shows the working procedures of the present invention.

7 L; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT ,ith reference first to FIG. 1, the varnishing furnace 1 according to the present invention is provided with three rows of near-ultrared radiation bulbs 2 on cne side, both sides, or both sides and bottom thereof. There is a distance betweeen every two rows of near-ultrared radiation bulbs 2. Then, the space enclosed by or just in front of the near-ultrared radiation bulbs 2 forms a high temperature region 3 while the space between two rows of near-ultrared radiation bulbs 2 builds up a low tuemperature region 4.

Looking now at FIG. 2, when a workpiece 5 enters into the varnishing furnace 1, the workpiece 5 is first preheated at a low temperature region 4 and then passed through a high temperature region 3. Since the nearultrared radiation bulbs 2 can increase the temperature quickly, the temperature of the workpiece 5 will produce heat due to the vigorous oscillation between the parties thereof and this will decrease the temperature difference between the upper and lower layers of painting on the workpiece 5. Hence, the time required for the solvent in the upper and lower layers 8 r Ily j of painting on the workpiece 5 to vaporize will be nearly the same thereby decreasing the occurrence of so-called pin hole and baking dead points. Further, the time difference between the /solidifying of the the upper and lower layers of painting on the workpiece will be diminished, avoiding the occurrence of socalled wrinkles. Thereafter, the workpiece 5 passes through a low temperature region 4 where the workpiece is only subject to indirect heat through the air.

This is because the near-ultrared radiation bulbs 2 has a short wavelength and small radiation range.

Apparently, the temperature at the low temperature region .1 will be lower than that at the high temperature region 3. The low temperature region 4 is 15 designed so that the temperature thereat is lower than that required for [stlid-fyiErg the painting on the workpiece 5. Meanwhile, the temperature of the workpiece 5 is gradually increased eliminating the time difference for the upper and lower layers of painting on the workpiece 5 to vaporize orLs.olidify. Lastly, the workpiece 5 passes a number of high and low temperature regions alternatively diposed for baking.

Other embodiments and modifications will occur to those skilled in the art. No attempts has been made to illustrate all possible embodiments of the invention, S Tt9 i i i_ i. 1 but rather intended such alternations and further applications as illustrated herein being contemplated as would normally occur to one skilled in the art to which the invention relates.

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Claims

1. A varnishing furnace comprising a plurality of near-ultrared radiation bulbs arranged in a number of rows longitudinally spaced along one side, or opposed sides, or opposed sides and bottom, of the furnace, thereby forming respective high temperature regions in the furnace in front of the rows of near-ultrared radiation bulbs, the high temperature regions being arranged alternately with respective low temperature regions in the furnace between adjacent rows of the near-ultrared radiation bulbs; so arranged that for painted workpieces travelling through the furnace: the temperatures in the high temperature regions are gerater than the temperature required to vapourize solvent in, and cure and harden, the paint on the workpieces; and the temperatures in the low temperature regions are lower than the temperature required to cure and harden the paint on the workpieces.

2. A varnishing furnace substantially as hereinbefore described with reference to the accompanying drawings. DATED this thirty-first day of May 1990. CHING-SHUN WU By his Patent Attorneys GRANT ADAMS COMPANY t N !A Or