WO2005107960A1

WO2005107960A1 - Paint booth by direct heating method for saving energy

Info

Publication number: WO2005107960A1
Application number: PCT/KR2005/000271
Authority: WO
Inventors: Ho-Seop Yeo
Original assignee: Power Tech Co., Ltd
Priority date: 2004-05-10
Filing date: 2005-01-29
Publication date: 2005-11-17
Also published as: KR100582864B1; KR20050107673A

Abstract

The present invention relates to a paint booth by direct heating method. The paint booth comprises: a burner 302 for blasting, injecting and igniting fuel; a furnace 301 for burning the fuel ignited by the burner 302; a combustion outlet 305 adapted to be fluid- communicated with each other so as to mix and blast the hot air exhausted from the furnace 301 and the air from the outside; a blast blower 304 for mixing and heating primarily the hot air from the combustion outlet and the cold air from the outside; a heat exchanger 306 in which the air primarily heated and mixed and exhausted from the blast blower 304 is heat-exchanged while flowing the outer surface of the furnace 301; a painting chamber 308 for allowing the hot air passed through the heat exchanger 306 to flow in through a ceiling duct 307 having a ceiling duct filter 315; and an exhauster 400 forr comprising a exhaustion blower 313 and a exhaustion filter 314 to exhaust the air coming out from the painting chamber 308 and cleaning in an exhaustion filter 314. According to the present invention, the paint booth has good heat efficiency and combustion in the furnace 301 is stable.

Description

PAINT BOOTH BY DIRECT HEATING METHOD FOR SAVING ENERGY

Technical Field The present invention relates to a paint booth by direct heating method. More

specifically, the invention relates to a paint booth, which comprises: a burner 302 for blasting,

injecting and igniting fuel; a furnace 301 for burning the fuel ignited by the burner 302; a

combustion outlet 305 and an air inlet 303 adapted to be fluid-communicated with each other

so as to mix and blast the hot air exhausted from the furnace 301 and the air from the outside;

a blast blower 304 for mixing and heating primarily the hot air from the combustion outlet

and the cold air from the outside; a heat exchanger 306 in which the air primarily heated and

mixed and exhausted from the blast blower 304 is heat-exchanged while flowing the outer

surface of the furnace 301 ; a painting chamber 308 for allowing the hot air passed through the

heat exchanger 306 to flow in through a ceiling duct 307 having a ceiling duct filter 315; and

an exhauster 400 for exhausting the air coming out from the painting chamber 308 and

cleaning in an exhaustion filter 314. According to the invention, the paint booth has a good

heat efficiency and combustion in the furnace 301 is stable.

Background Art The present invention provides a method and a device for heating efficiently a

painting chamber 308 of a paint booth, in which both painting and heat treatment can be done

using a fan 300 and an exhauster 400.

A painting chamber of a paint booth that is used for both painting and heat treatment is provided with air by a blast blower while painting, and the air provided to the painting

chamber is exhausted outside by an exhaustion blower with the paint sprayed in the painting

chamber. After painting has been completed, in order to dry the painted object, heat is

provided to the painting chamber by a blower, raising temperature of the painting chamber for

heat treatment. When treating heat, high temperature air is provided to the painting chamber

by a blast blower and a heat supplying device in the blower, so heat is treated.

When painting, generally, a paint booth is used without operating a heat supplying

device, but, in case that painting quality is deteriorated by very low outside temperature, the

outer air heated about 20 ^°C is provided to a painting chamber. A conventional paint booth by indirect heating, as shown in FIG.1, largely includes a

ceiling duct 106 and a floor duct 110, consisting of a painting chamber 108 which is used for

painting, a blower 100 which heats the outer air and provides it to the inside of the painting

chamber 108 through the ceiling duct 106, and exhauster 500 which absorbs paint and organic

compounds generated at the painting chamber 108 using a exhaustion filter 112, and exhausts

outside the air purified using a exhaustion blower 111.

Specifically, the blower 100 consists of a suction filter 120 which removes dust when

sucking the outer air, a blast blower 104 which blasts the air that has passed the suction filter,

and a heat supplying device which heats the blasted air.

A heat supplying device of a paint booth by indirect heating consists of an ignition

burner 102, a fuel injection hole, a furnace 101 which burns the fuel injected by the ignition

burner 102, a heat exchanger 105 which transfers the heat of the combusted hot air, and a

combustion outlet 113 which exhausts the combusted air that transferred heat. The air that

flows in from the blast blower 104 receives heat through the heat exchanger 105 using an indirect heating method and flows inside the painting chamber 108.

However, the heat exchange efficiency of an indirect heating method is no more than

40 - 50%, consuming much fuel. To enhance heat exchange efficiency, the surface area and

the volume of the heat exchanger 105 should be increased. However, increase of the surface

area and the volume of the heat exchanger 105 raises production costs, worsening the price

competitiveness and causing the increase of construction and land costs.

On the other hand, to solve the problems of a paint booth of an indirect heating heat

exchange method, the present inventors invented a direct heating paint booth and applied for

the Korean Patent Application 10-2001-0055230. The direct heating method was invented to

solve the problem of low energy efficiency of conventional methods, which is a very practical

and useful heat supplying method for paint booth, maximizing energy efficiency and

simplifying the structure. As shown in FIG. 1 , compared with a conventional indirect heating

method which exhausts, after combustion, the combusted hot air through combustion outlet,

the patent-applied direct heating method, as shown in FIG 2, has a configuration that the hot

air combusted in the furnace 201 is exhausted through combustion outlet 206, is heated first

together with the cold air from the outside which flow into the painting chamber, is heated / second by the heat exchanger, and flows into the painting chamber again.

However, a conventional direct heating method includes a ceiling duct filter to

remove dust in a ceiling duct, where the air which flows into the painting chamber is passing.

A ceiling duct filter is a very dense filter, so that pressure is applied to pass the filter.

Therefore, since positive pressure is applied next the blast blower 204 because of the ceiling

duct filter, the hot air which is provided from the burner 202 through the furnace 201 is

exposed to the positive pressure, so that, to be mixed with the outside cold air, the blasted air pressure of the burner 202 should higher than the positive pressure which is caused by the

ceiling duct filter. In this case, to provide pressure to the burner, excessive pressure of the air

which is supplied to the burner is required, therefore ignition of the burner and control of

temperature in the paint booth become difficult. On the other hand, when a furnace burns, the internal temperature of a furnace 201

goes up more than 1000 ^°C, and when the furnace stops burning to control temperature, it falls

down abruptly as low as room temperature because of the heat exchange. Generally, a

furnace 201 is made by stainless steel which has a high coefficient of thermal expansion, so

that, according to frequent heating and cooling, welded joints of a furnace 201 may have

cracks. At this time, if a flame leaks through a crack of a welded joint by high blast pressure

of the inside of a burner 202, floating particles, like dust, at the ceiling duct may catch a fire,

resulting in a fire of the paint booth with neighborhood of heat exchanger and dust of the

ceiling duct.

Disclosure of Invention

The present invention has been made in order to solve the above problems in the prior

art which are caused by the excessive blast pressure of a furnace and to supply heat

effectively, and it is an object of the invention to provide a paint booth by direct heating,

which maximizes energy efficiency, is safe without having danger of fire even when a furnace

has a crack by lowering blast pressure of the furnace, and is very practical and useful because

of the simple structure.

In order to accomplish the above object, according to one aspect of the present

invention, an air inlet is connected to the combustion outlet which exhausts combusted hot air flowing out from the furnace.

Brief Description of Drawings

Further objects and advantages of the present invention can be more fully understood

from the following detailed description taken in conjunction with the accompanying drawings,

in which:

FIG. 1 shows a conventional paint booth by indirect heating; FIG. 2 shows a heat exchanger of a conventional paint booth by direct heating; FIG. 3 shows a paint booth by direct heating according to the present invention; and FIG. 4 shows a combustion-filter-added paint booth by direct heating according to the

present invention.

Best Mode for Carrying Out the Invention

The preferred embodiments of the present invention will be hereafter described in

detail with reference to the accompanying drawings.

FIG. 3 shows a structure of a paint booth according to the present invention. The

paint booth includes a suction filter 320, a blast blower 304, a furnace 301, a combustion

outlet 305, a heat exchanger 306, a conversion damper 311, a burner 302, and a combustion

filter 330, and comprises a blower 300, in which the upper portion is connected to a ceiling

duct 307, and the combustion outlet 305, which is configured to supply hot air combusted in

the furnace 301 to the blast blower 304, is fluid-communicated with an air inlet 303; a painting chamber part which includes a ceiling duct 307, a ceiling duct filter 315

which enters and passes a painting chamber 308 from the ceiling duct 307, a painting chamber 308, a floor grating 309 installed at the lower portion of the painting chamber, and a floor

duct 310; and an exhauster 400 which includes a conversion damper 312, an exhaustion filter 314,

and an exhaustion blower 313. A paint booth according to the present invention will be hereafter explained in detail.

The heat supply method of the painting chamber 308 is a direct heating method. The

combustion outlet 305, which exhausts the hot air exhausted from the furnace 301, is fluid-

communicated with the air inlet 303, flowing air into the blast blower 304, therefore the hot

air exhausted from the combustion outlet 305 and the cold air flowing into from the outside

through the suction filter 320 are mixed and first heated through the blast blower 304, and

heated second while the heated air is passing the heat exchanger 306.

More specifically, the painting booth comprises a burner 302 which is capable of

blasting, injecting and igniting fuel; a furnace 301 which burns the fuel ignited by the burner

302; a combustion outlet 305 and an air inlet 303 which are combined to mix and blast the hot

air exhausted from the furnace 301 and the air from the outside, and a blast blower 304 which

mixes and heats first the hot air from the combustion outlet and the cold air from the outside;

a heat exchanger 306 which makes the air, which is heated first and then mixed and exhausted

from the blast blower 304, exchange heat while flowing the outer surface of the furnace 301; a

painting chamber 308 which allows the hot air, which has passed the heat exchanger 306, to

flow in through a ceiling duct 307 that includes a ceiling duct filter 315; and an exhauster 400

exhausting the air coming out from the painting chamber 308.

Hereafter, FIG. 3 depicted as an embodiment of the present invention will be

explained more specifically. The fuel ignited by the burner 302 which is capable of blasting, injecting fuel, and

igniting burns with oxygen in the air blasted in the furnace 301, heating the air blasted from

the burner 302, and the hot air exhausted from the furnace 301 is exhausted through the

combustion outlet 305 located at the bottom of the furnace 301. Since the combustion outlet 305 is fluid-communicated with the air inlet 303 where

the blast blower 304 is resting, the heated hot air flows in effectively to the ceiling duct 307

through the combustion outlet 305 by the suction operation of the blast blower 304 which is

resting at the blower 300 connected to the ceiling duct 307.

On the other hand, the cold air flows into the air inlet 303 through the suction filter

320 by the suction operation of the blast blower 304, and is mixed with the hot air, flowed in

through the combustion outlet 305, by the blast blower 304, being exhausted through the

exhaustion outlet of the blast blower 304.

The mixed air, the air heated by the first direct heating method which comes through

the combustion outlet 305 and the cold air flowed in from the outside, is heated second while

passing the heat exchanger 306 again, improving the thermal efficiency more. The heat-

exchanged air flowed into the ceiling duct flows into the painting chamber 308 through the

filter which is included in the ceiling duct filter 315.

After playing the role of heat treatment for painting or drying in the painting chamber

308, the heat-exchanged air flowed into the painting chamber 308 may be exhausted to the

outside through the exhauster 400 which includes an exhaustion filter 314 and an exhaustion

blower 313 (mainly adopted in painting operation), however, since the air exhausted from the

painting chamber 308 is the air with temperature higher than the room temperature containing

waste heat, the air passed through the painting chamber may be recycled (mainly used in case of heat treatment for drying) to flow into the blower 300 again and reuse the exhausted air by

installing the floor duct 310 additionally and combining the floor duct 310 with the blower

and ceiling duct 307.

Since, according to the present invention, while painting, the paint booth does not

need to flow the hot air into the painting chamber 308 and only the air from the outside is

flow in and flow out to maintain the operation environment in the painting chamber 308, the

air exhausted from the painting chamber 308 is exhausted outside through the exhauster 400.

When performing the heat treatment process after the paint operation, the hot air heated by the

direct heating method, after flowing into the painting chamber 308, is circulated to the blower

300 again and mixed with the first heated air which is exhausted from the furnace 301.

That is, since the air does not need to be heated while painting, the air which passed

the painting chamber 308 is exhausted to the outside by the exhauster 400, but, when drying

paint, to maintain the temperature between 60 and 80 ^°C, the conversion damper 311, 312,

which can be selectively opened and closed, is installed in order not to exhausted the air

which passed the painting chamber 308 to the outside by the exhauster, but to be fluid-

communicated with the floor duct 310 at the lower portion of blower 300, so that the heated

air which passed the painting chamber can be recycled by the blower and the ceiling duct. In

order to accomplish the purpose, a conversion damper 311, 312 is installed so that the air may

be selectively exhausted by the exhauster 400 or recycled to the blower 300 by the floor duct

310, allowing the operator of the paint booth can selectively operate.

In the combustion method of direct heating according to the present invention, the

fuel which is ignited at the burner 302 and the air which flowed in by the burner blast blower

(not configured) which supplies air to the burner 302 are burnt in the furnace 301 at between 500 and 1200°C for 0.2 to 3 seconds, but, considering thermal efficiency and economic point

of view, it is desirable to be burnt at between 800 and 1000^°C for 0.5 to 2 seconds. The

furnace continues the above combustion repeatedly to maintain the predetermined

temperature. The burnt air flows into the blast blower 304 which is fluid-communicated with

the combustion outlet 305 through the combustion outlet 305, is mixed with the cold air of the

outside, passes the heat exchanger 306, and is blown into the painting chamber 308 through

the outlet of the heat exchanger 306 by way of the ceiling duct.

Diesel, kerosene, LPG, and LNG may be used as fuel for the combustion method of

direct heating, but LPG or LNG, clean fuel, is more desirable. In addition, it is desirable to change the structure of a burner according to the type of

fuel. For example, in case of using clean fuel such as LPG and LNG, generally, they are

added with bad smelling materials to detect leakage. However, by opening the gas fuel valve

slowly the burner ignites the fuel, so that small amount of fuel flowed into the burner before

ignition is not burnt completely and flows into the painting chamber through the blower 300.

In case of painting operation, people work in a painting chamber and the burner bums and

extinguishes repeatedly to control temperature, so that operators feel bad because of the bad

smelling materials, causing a headache if excessive. (It does not matter when drying the paint,

since there is no operator.) Therefore, to minimize the flow of the incompletely burnt bad

smelling materials into the paint chamber, both a supplementary burner which maintains the

temperature of the combustion chamber and a main burner which controls the temperature of

the painting chamber are installed. The supplementary burner bums incessantly while heating

and the main burner bums continually for a predetermined time as explained above. Like this,

by using a supplementary burner and a main burner together, the incompletely burnt bad smelling materials can be removed, so that the operator may not smell the bad smelling

materials while working in the painting chamber.

A High/Low type burner may be used instead of a supplementary burner and a main

burner, which bums fervently with strong flame while heating and maintains only the

temperature of the furnace with mild flame while maintaining temperature, thereby

minimizing the fuel that burnt incompletely at the time of ignition by igniting the burner only

once when providing heat.

In addition, in case of using kerosene or diesel as fuel, much more soot is produced

compared with gas at the time of ignition and combustion. So that, when the burnt air

exhausted from the combustion outlet 305 flows into the painting chamber through the blower

300, soot is filtered by the ceiling filter, thereby shortening the life span of the ceiling duct

filter. So that, when using the above fuel, it is desirable to remove soot or dust in advance

through the combustion filter 330 before the air flows into the blast blower 304 through the

combustion outlet and then flows the air into the blower. (Refer to FIG. 4)

Industrial Applicability

As described above, a paint booth by direct heating according to the present invention

uses all the combustion heat by direct combustion and heating, thereby increasing thermal

efficiency, minimizing fuel consumption, and decreasing the construction costs practically by

the small heat exchanger and removal of the combustion exhaustion duct.

In addition, the pressure of the blasting air of furnace is lower than the air which

flows to the ceiling duct through the heat exchanger, eliminating the danger of fire when the

furnace is cracked, consequently it is safe. While the present invention has been described with reference to the particular

illustrative embodiments, it is not to be restricted by the embodiments but only by the

appended claims. It is to be appreciated that those skilled in the art can change or modify the

embodiments without departing from the scope and spirit of the present invention.

Claims

What Is Claimed Is:

1. A paint booth for performing a painting and a heat treatment at the same time,

the paint booth comprising a blower, an exhauster, and a painting chamber, wherein a

combustion outlet for exhausting hot air heated at a furnace in the blower is fluid-

communicated with an air inlet having a blast blower rested therein, the air burnt in the

furnace and cold air from the outside are mixed by the blast blower and primarily heated, and

the mixed heated air is secondarily heated while passing through a heat exchanger in the

blower and flows into the painting chamber.

2. A paint booth for performing a painting and a heat treatment at the same time,

the paint booth comprising: a burner 302 for blasting, injecting and igniting fuel; a furnace

301 for burning the fuel ignited by the burner 302; a combustion outlet 305 and an air inlet

303 adapted to be fluid-communicated with each other so as to mix and blast the hot air

exhausted from the furnace 301 and the air from the outside; a blast blower 304 for mixing

and heating primarily the hot air from the combustion outlet and the cold air from the outside;

a heat exchanger 306 in which the air primarily heated and mixed and exhausted from the

blast blower 304 is heat-exchanged while flowing the outer surface of the furnace 301; a

painting chamber 308 for allowing the hot air passed through the heat exchanger 306 to flow

in through a ceiling duct 307 having a ceiling duct filter 315; and an exhauster 400 for

exhausting the air coming out from the painting chamber 308 and cleaning in an exhaustion

filter 314.

3. The paint booth according to claim 2, further comprising a floor duct 310 and

conversion dampers 311, 312 such that the air exhausted from a painting chamber 308 flows

again into the blower 300.

4. The paint booth according to claim 2 or 3, wherein a combustion filter 330 is

further provided for filtering dust or soot of the hot air before the hot air of the combustion

outlet 305 flows into the blast blower 304.

5. A paint booth according to claim 2 or 3, wherein the burner is selected from a

main burner, a supplementary burner, or a High/Low burner.