DE2253487A1 - DEVICE FOR PERFORMING A HEAT TREATMENT ON COVERS ON A CONTINUOUSLY FORWARDING TRAIL, IN PARTICULAR SHEET METAL - Google Patents

Description

Device for carrying out a heat treatment on coatings on a continuously advancing path, in particular Sheet metal track

The invention relates to a device for carrying out a heat treatment on coatings on a continuously advancing one Railway, especially sheet metal.

In the past few years there have been more and more areas of application result, where raw material or semi-finished products are provided with color or otherwise treated before the final product is molded. Typical for this procedure is the coloring or painting of sheet metal semi-finished products, before it is deformed in the die. To do this, an excellent coating is required which is wear-resistant enough to withstand acid, caustic or the like

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the same, and the coating must also be scratch-resistant and abrasion-resistant. In numerous use cases paint that contains epoxy compounds is used. The advantage of overlaying geometrically flat material instead geometrically complex end products is evident. This manufacturing method also allows the inside to completely cover or coat and protect the product.

Heretofore, the high cost of these coatings has been offset by the ease of handling and the high speed at which the final product can be formed, but only in limited areas. Because of this high cost, the applications that use this technology are quite limited. Equipment is expensive and the coatings require temperatures on the order of 120 to 260 ^° C (250 to 500 ^° F). The final application must be completely and evenly distributed and checked very carefully and precisely. After the coating has been applied, the surface cannot be touched until the coating has cured in a suitable manner by means of a heat treatment. In the case of coating or covering long strips of semi-finished products such as sheet steel wound from a roll, the length of the treatment furnace is the determining factor that determines the speed at which the coating can be applied, as this is precisely through the arch or the sag of the Material is dictated when the material is pulled through the furnace. With the equipment available today, the time that the material must be exposed to the heat treatment limits production to approximately 0.5 to 0.76 meters per second (100 to 150 feet per minute). This limiting one

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Factor makes the policy of "pulling over before." Molding "economically impracticable for most mass-produced items, for example for the automotive industry. However, according to the present invention, the Heat treatment can actually be carried out in less than a third of the time previously required, thereby reducing the Production speed is nearly tripled with the result of correspondingly reduced costs. One of those marked improvement has made the process economically viable for mass production systems as in automobile manufacturing, in such a way that at least one of the major automobile manufacturers in the United States is currently in the process of converting its production to this system by moving from the present Invention makes use.

There are different types of coating or coating, each of which requires different treatments. Some coatings that are applied in liquid form require an evaporation time and then heat cure, while others are curable by preheating the metal and then applying the coating.

According to the present invention, an apparatus for heat treatment of sheet material such as sheet metal is provided, which is wound in the form of large coils. Web material is unwound from the spool and secured with a suitable one Coating material such as paint coated and then passed through a heat treatment chamber in the form of an arcuate shape sagging track. The heat treatment apparatus according to the present invention includes a plurality of Building blocks or module sections running along the length of the web

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are arranged one behind the other when they are traversed by the web.

Each of the modular or modular units is a specific point within the heat treatment of each particular one Material type assigned. When applying the invention on For the treatment of paint, for example of the epoxy type, which is applied to sheet metal sheets, the heat treatment device has the following modular units arranged one behind the other: a suction or evaporation section, a Section with dynamic flow conditions and a high-speed section. The second and third sections use special burners arranged in a special way. At both ends, that is, at the inlet and Air curtains are provided at the outlet end of the device to specifically remove boundary layers as well to close off the ends, as will be described in detail later. If necessary, a second one can also be used Furnace section with dynamic flow conditions and a high-speed section together with a suction section be provided in order to undertake a further treatment of the material. In fact, there can be so many at a time Modular units are provided that are required to treat the material, although it is because of the extremely high Efficiency of the device according to the invention is normally not required.

The primary object of the invention is to provide a high speed heat treatment apparatus for web material.

According to the invention, a heat treatment device is to be provided

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will see the special air jet curtains at the entrance and outlet ends of the apparatus used to remove air boundary layers following the path for the heat treatment to reinforce, and to remove the boundary layer of hot gases from the web to cool down to reinforce the web material.

In addition, the present invention aims to provide a heat treatment device be provided, which works with extremely high efficiency and extremely quickly, whereby a Coating process prior to molding for many fields of application is economically applicable and whereby the It should be possible to achieve significant cost savings and a high quality of the end products.

These and other essential objects and advantages of the invention will become apparent to those skilled in the art a person skilled in the art easily works from the following description, in which the invention is explained in more detail using exemplary embodiments with reference to the drawings will. In the drawings show:

1 shows a side view of a device according to the invention;

Fig. 2 is an end view of the apparatus of Fig. 1 for illustration of the inlet end;

Fig. 3 is a schematically drawn longitudinal section through the The device of Fig. 1; .

4 is an enlarged sectional view of one of the burner assemblies.

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Reference is made in particular to FIGS. 1 and 2 below taken where a heat treatment device forming an embodiment for a heat treatment of web material is shown and designated as a whole with 10. The device basically comprises an elongated one Tunnel with an inlet end 12 and an outlet end 14. They has a variety of different functions taking over heat treatment sections, an evaporation or suction section 18, a section 16 with dynamic Have flow conditions and a high-speed section 10. Devices 22 and 24 for training of air curtains are placed at the inlet and outlet ends of the tunnel. Each of the sections can be used as a modular or building block construction designed and suitably connected and connected to a heat treatment device to form any or all of the aforementioned sections in any desired length and arrangement as the case may be the special materials to be treated there. For example, in the case of a heat treatment of color substances on semi-finished metal products, it is sometimes desirable to provide all of the above-mentioned sections, that is, sections for evaporation or suction, with dynamic flow conditions and with high-speed conditions that are arranged together, the section with dynamic flow conditions being the largest in terms of its length is so that a web moving therethrough is subjected to this particular treatment for the greatest period of time is. The evaporation or extraction section 18 is provided with a hood 25 at the upper end and via lines 26 to a Exhaust fan 28 connected. This arrangement removes the gases and volatiles from the web material and leads this through an afterburner 30, which is via a trigger 32 for

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Is vented towards the atmosphere.

With additional reference to Pig. 3, various sections of the heat treatment device in FIG individually described. Normally, the web W moves along the central part of the heat treatment device in FIG a substantially horizontal plane, it being pointed out is that the web sags in an arc when only supported at both ends. The different Portions of the device act above and below the web to treat both surfaces at the same time. Of the The upper part of each section is therefore described in detail, with like reference numerals bearing "d © n-Xnde-x (') to designate like components in the lower part to be used.

When the web begins its passage through the device, it first passes through the detachment or evaporation or take-off station 18. This take-off section 18 of the device lies next to and in front of section 16 with dynamic flow conditions and downstream thereof with regard to the movement of the web W. The take-off section removes volatile gases, which are sometimes close to 700-750 dmVh (200 gallons per hour). The gases are removed by passing the web through a fume hood where the volatile gases are removed by an exhaust fan removed. The removal of the gases can be accelerated by a plurality of suitably arranged Air nozzles 52, which are arranged so that thereby a jet-shaped air flow from above and below on the Surface of the web is straightened. In some cases it can

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heated air is diverted from one of the heating sections into the vent section who, to let the volatile substances evaporate with increased effect. In case that If volatile constituents are to be vented from the vent section to the atmosphere, it is desirable that the remove volatile constituents in a safe manner. An air purifying device similar to that previously described Has the exhaust vent 28 and the afterburner 38 can be provided for this purpose. The gases are with withdrawn from the trigger section at high speed and passed through the afterburner 30, where a plurality of Burners 54 of similar construction to the burners in the dynamic flow section is arranged. The gases are ignited and burned, and the harmless fumes are then passed through the vent 32 discharged into the atmosphere. A suitable air purification method and a corresponding device for treating volatile substances is shown and described in US Pat. No. 3,497,308.

The section 16 with dynamic flow conditions is a highly effective convection heater with upper Walls 33 »bottom walls 35 and side walls 37, respectively of insulated construction creating a tunnel-like structure with open ends. The furnace has a central heated oven chamber 34 and a pair of opposing air chambers 36 and 36 'which next to the upper and lower walls of the chamber.

The air chambers 36 extend over the length and width the heating chamber 34. A large number of high-volume burner

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Units 38 is arranged to bring hot gases into the furnace chamber 34 through a plurality of elongated, spaced guide members 40 to drive. Air nozzle assemblies 42, which are next to the guide bodies, are connected from a pressure medium source (not shown) to the hot gases in the furnace chamber 34 have a dynamic venturi effect granted.

The air nozzle assemblies 42 include a number of openings (not shown) drilled in a conduit 39 connected to the well. The openings or holes are drilled along the pipelines 39 at predetermined intervals across the width of the furnace. The openings are made large enough to provide the effective speed of treatment required. With others In other words, the farther away the rays are from the treatment site, the larger the openings. At a practical example of application of the invention is air from the openings at a speed of 91.5 m / sec. (18 "Feet per minute") using a 24-oz entrained air in the chamber is sucked in to circulate and generate a high level of turbulence, which is at least the IiIm adhering to the heated material is eliminated. That The minimum entrainment ratio is approximately 40: 1, that is, for every 28 dnr (I cubic feet) of air exiting the

Orifice, there are at least 1133 diir (40 cubic feet) sucked into or carried away by the flow, with the same effect as for a volume of 28 dnr (1 cubic foot), which normally occurs at 1133 dm ³ (40 cubic feet) Ci ¹ M), which flow at approximately 55 feet per second (15.5 m / sec). The higher the temperature is at

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that the furnace works, the greater the speed, and consequently also the turbulence.

Each burner assembly 38 includes an elongated manifold 44, which is fed with a pressurized combustible gas mixture, for example from Natural gas and filtered air. The air is supplied to the manifold 44 from a filter 46 via suitable conduits 48 where it is combined with the gas in a mixer 50. A fan assembly 45 is provided to the To direct air through the filter and through line 48 to the mixer 50 under pressure. The outlet of the mixer is with connected to each of the burner connections or distribution lines via lines 43.

4 also shows that each burner assembly 38 has a plurality of adjacent cooperating ones Burner units 39 comprise, which extend generally along the width of the furnace within the manifold 44 extend. The burner units are preferably those shown in US Pat. No. 3,232,593 Construction on. Each burner has a hollow receptacle housing 41 with an inlet port 43 and an open front, which is covered by a thin porous combustion layer 45, which in turn is opposite the open side of the housing is sealed and is held above this by means of a sieve device 47. The combustion layer 45 can consist of a metal fiber, a thin porous ceramic felt or a fine mesh screen. The combustible gas mixture is caused to emerge substantially uniformly from the porous combustion layer in order to adhere to it Burn outer surface. Brackets 49 support upright on the circumference

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arranged channel walls 51, which form an elongated outlet opening 54 serving for the conduction of the hot gases with discharge into the air chambers 36 on opposite sides of the web. . . ■ -

Any number of burner assemblies 38 can be used as required be provided in each section 16 with dynamic flow conditions. In the one shown in Mg Embodiment several sections 16 are shown with dynamic flow conditions, each Section has an upper and a lower burner arrangement 39 and 39 ', which are connected and arranged there are. The sections with dynamic flow conditions are arranged in a row one behind the other in order to achieve the to form elongated heating chamber.

After the path through the evaporation or withdrawal, - and the sections with dynamic flow conditions have run, they can be subjected to further heat treatment a high speed section 20 are subjected. The high speed section includes a plurality of Burners 56 that are similar to burners 38 and 54 previously described. The burners 56 are arranged so that they heated gases at high speed towards the top and bottom surfaces of the web conduct as the web passes through the furnace chamber 57. Each of the high speed burners 56 has a number of individual ones Burner units with an inlet port and an open one Front surface, each covered by a thin layer of combustion held in place by means of a sieve is of the type previously discussed in connection with the section with dynamic flow conditions

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Written and in Pig. 4 is shown. The burners are in a manifold 66 which extends the width of the chamber 57 * A plurality of manifold burner assemblies 56 is distributed in the form of rows across the chamber, their spacing and number being determined by the nature of the straight treated material, Any high velocity burner manifold assembly includes a positive pressure pressure chamber 58 similar to port 53 shown in FIG and has a restricted outlet 60 which has a large volume and high temperature output generated by heated gases. This gas output is higher Speed is directed to the surfaces of the web. The top, bottom and side walls of the Örenner are off an insulating material 59 similar to that used in connection with the section 16 with dynamic flow conditions is shown. The insulation material and construction for the high speed section must, however, be designed for higher temperatures, since the high-speed sections at continuous Operation tend to reach higher temperatures than the section with dynamic flow conditions.

A combustible mixture of gases and air is formed in mixer 62 and via line 64 into the distribution chamber 66 of each burner assembly 56 inserted. The volume and temperature of the flow rate can be changed by changing the Pressure and the gas mixture supplied to the burner can be regulated. Which have large volumes and a high temperature Gases developed on the burner surface are injected into the pressure chamber 58. The pressure in the Chamber 58 creates a driving force to force the gases into the furnace chamber 57 through the restricted outlet 60. the

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Exit flow from the narrowed outlet can be within the ' Oven, as shown by the arrows shown at the outlets 60, can be directed in different directions. In the one in Pig. 3 are the burners 56 located at the inlet end of the high speed section are arranged, with a view to the movement of the web 7 upstream, whereby a proportion of the with high speed and high pressure gases flowing in the direction of the section 16 with dynamic flow conditions is injected towards. Further executors via one high velocity burners suitable for the practice of the present invention can be found in U.S. Patent 3,390,944.

The devices 22 and 24 provided for producing air curtains or for removing boundary layers, which are arranged at the inlet and outlet ends of the heat treatment device, are connected via a corresponding line 27 to a compressed air source. Like from the Pig. 2 and 3, the air curtain devices 22 and 24 each include a pair of tubes 23 and 23 'extending across the width of the ends 12 and 14 of the furnace. Each of the tubes has a plurality of orifices or nozzles 29, to direct a high velocity stream of air at an acute angle onto the surfaces of the web with respect to the opening as indicated by arrows in FIG. In some applications, the pressure needs to be only slightly _greater, than the ambient pressure, and piping 27 may be directly connected to the same pressure source which is used for feeding the burner.

The operation of the device is as follows;

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The material subjected to the heat treatment is applied to both ends of the heat treatment apparatus in a conventional manner held and supported and is pulled through the oven at a predetermined rate depending on the desired treatment. After the application or coating, for example paint, has been applied to the web, the surface cannot be touched until the heat treatment is completed. The web material is painted, coated, coated or treated in a different way in the conventional manner and enters the at the entrance end (left side with reference to FIG. 3) Heat treatment device. A layer or film of air (sometimes called a boundary layer) follows the surface the train when it moves forward. When the web surface reaches the evaporation section and in When this occurs, the air curtain members 22 located upstream direct a high velocity air flow onto the surface of the web, preferably at an acute angle thereto, as a result of which turbulence is developed thereupon, and remove it the adherent boundary layer by "peeling off" it, the web surface of the subsequent heat treatment is exposed. As known to those skilled in the art, the volatile gases are removed when the Web passes through the evaporation or discharge section. This can of course be done in a number of ways, though to avoid environmental pollution, it is preferred to treat the gases by placing them in an afterburner 30 leads, as has already been described in various ways. Since the exhaust vent 28 creates a zone of reduced pressure within the vent section, air flows from areas of higher pressure, that is, from the section 16 with dynamic flow conditions and the high-speed section 20 in FIG An evaporation or exhaust section. Air nozzles 52, the

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are arranged halfway and below the web, help to remove 'the solvents by creating turbulence and a flow of the gases that removes the volatile solvents. The train then enters the section with thermal flow conditions.

The hot gases that fill the air chamber 36 of the section 16 with dynamic flow conditions are with drifted continuously at a considerable speed into the furnace chamber 34 under the influence of the Venturi effect, the from the high pressure nozzle assemblies 42 results. The hot gases and drive air mix when they enter the furnace chamber flow in, creating a heat convection with a relatively high temperature and under dynamic flow conditions is applied to the surfaces of the web in oven chamber 34.

After going through the section with dynamic Flow conditions can subject the material to a further heat treatment in the high-speed section 20 which provides a more localized application of the hot gases. Generally the high speed section leads to a heat treatment at a significantly increased temperature in order to cure and solidify the final order. The heated ones Gases are directed from the constricted outlet 60 onto the web surface in the furnace chamber 57 at high velocity.

When the train stops moving from the high-speed section continues, the hot gases form another boundary layer that adheres to and follows the web material. If- the train with the If the boundary layer adhering to it is pulled out of the oven, the web has a tendency to remain hot, the heat tending to to overcure the tempered or finished material. It is therefore desirable to have a second air curtain or air curtain

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-Oil device 24 for removing the boundary layers at the outlet end of the heat treatment device. Air jets are applied from the air curtain device 24 onto the surface of the web, preferably at an acute angle, directed and break the boundary layer of the hot gases or break them up follow the track to expose the surfaces of the track to the surrounding atmosphere, thereby rapidly cooling them is attainable. The curtain also closes off the outlet end of the tunnel and holds, since it is at an acute angle in the direction towards the outlet end (see Fig. 1), most of the hot gases are within the furnace. As for the one in this field As is apparent to those skilled in the art, a final vent section may be adjacent the outlet end of the high speed section be arranged to remove the heated gases.

The slack or arcuate shape of the web in the oven between its support points at the ends of the oven determines the length the web that can be subjected to the heat treatment. This in turn determines the speed at which the coating is applied and the heat treatment can be carried out. In so far common systems is the fundamental factor that affects all heating and heat treatments and the length of stay in the Furnace has a decisive influence on the heat transfer rate. This in turn depends on the oven temperature the effectiveness of the contact of the hot gases, the heat exchange on the article surfaces, the intensity of the radiant heat and the rate at which the vapors are removed from the article surfaces. As for the one on this one As will be readily apparent to those skilled in the art from the foregoing description, the present description diminishes Invention, the necessary length of stay compared to the conventional equipment significantly by reducing the

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time necessary for handling the spell. When using the In the present invention, the surfaces can be reduced in less than a third of what is necessary for conventional equipment Time to be treated. Therefore, the production can be increased approximately three times that of the conventional one Systems, which results in considerable cost savings.

While a preferred embodiment of the invention is described and is shown, it should be noted that other modifications and variations of the invention are possible are who make use of the teaching according to the invention.

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Claims (10)

Claims (1J device for a high speed one Heat treatment of coatings on a continuously advancing path, in particular sheet metal by a heating chamber (34, 57) with side, lower and upper walls (37 »35, 33) which form an elongated tunnel having an inlet end (12) and an outlet end (14) for passing a web (W) therethrough; a hot gas generating burner assembly (38) located in the Chamber (34, 57) next to the aforementioned walls for generating a continuous flow of hot gases over the upper ones and disposed lower surfaces of the web (W); a plurality of individual burner units (39) as a component each burner arrangement (38) provided for generating hot gases, each burner unit (39) from a housing (41) with a gas inlet device (43) connected there and formed with one open side which is covered by a porous combustion layer (45) and with a screen holder (47) for Formation of a burn surface; a distributor device (44) connected to the inlet device (43) of each burner assembly intended for the production of hot gases (38) for supplying a flammable mixture - 19 309822 / 03QS is closed, and an air curtain device (22, 24) on at least one of the inlet and outlet ends (12 and 14, respectively), these devices directed at an acute angle to the 'continuous path (¥) is to peel and remove the gaseous boundary layer on the web (W) passing through this chamber (34, 57). 2. Device according to Ansoruch 1, characterized in that the air curtain device (22, 24) at the inlet end (12) of the heating chamber and at the outlet end (14) of the heating chamber to remove the boundary layer of the ambient air at the inlet end (12) of the heat treatment device and appropriately removing the boundary layer of heated air at the outlet end (14) of the device. 3. Apparatus according to claim 1, characterized in that trigger devices (18) in addition to the Heating chambers (34) located at the inlet end thereof for removing volatile gases from the coating on the web (W). 4. Apparatus according to claim 2, characterized in that g e k e η η - ζ e i c h η et that the air curtain device (22 or 23) is arranged at an acute angle with respect to the path (W) and opposite both said ends, in order to avoid the high-speed currents of air onto the web (W) to peel off the cool boundary layer of air from the web (W) at the inlet end (12) and to peel off the hot boundary layer of air from the web (W) at the outlet end (14). 5. Apparatus according to claim 2, characterized in that g e k e η η - 309822/0305 _ ₂ o - indicates that the air curtain device (22, 24) is arranged 1st next to an upper and lower part of said ends, being the high-speed flow of air on the the upper and lower surfaces of said web are directed at an angle thereto to peel off the boundary layer therefrom and to close said ends so that the heated gases are retained in the chamber. 6. The device according to claim 3, characterized by a second heating chamber (57) downstream of the the first-mentioned heating chamber (34) is arranged and has lateral, lower and upper walls, which have a second elongated Forming tunnels with an inlet and an outlet end for the web (W), as well as burners generating hot gases, which are arranged adjacent the upper and lower walls of the second chamber for introducing a high speed jet of heated gases onto the upper and lower surfaces of the web, each burner device comprising a housing which has a Hot gas pressure chamber with a narrowed outlet opening (60) of the pressure chamber (58), thus forming a hot gaseous flow can take place from the pressure chamber (58) into the heating chamber (57), while maintaining a positive pressure in the pressure chamber (58) and by a burner intended for combustion with a combustion surface in said housing, wherein the hot gas pressure chamber (58) and the constricted nozzle outlet (60) a High velocity flow of hot combustion gases in a jet stream from said outlet onto the surfaces cause of the mentioned path. 7. Apparatus according to claim 6, characterized in that the air curtain devices at the inlet end the first-mentioned heating chamber and at the outlet end of the second 309822/03 - 21 - named heating chamber are arranged around the boundary layer of the Ambient air at the inlet end of said heat treatment device to remove and to remove the boundary layer of heated air at the outlet end from here. 8. Heat treatment device according to claim 7, characterized in that the trigger devices with a blower (28) having an inlet and an outlet for removing volatile gases from the area of the auxiliary devices having, wherein the outlet is connected to a discharge line (32) which has a discharge opening, and that burners are provided in the flue line which has an inlet for a combustible gas mixture and one Hot gas discharge surface, which is in the direction of the discharge end of the vent (32) is directed to here a zone with a flow of hot gases for continuous ignition and produce combustion of the volatile gases prior to their passage through the vent 32. 9. Apparatus according to claim 7, characterized in that the trigger devices (18) also a plurality of air nozzles arranged above and below the web (W) to provide a continuous one Directing a jet of compressed air onto the surface of the web, to expedite the removal of the volatile gases therefrom. 10. The device according to claim 1, characterized in that the heating chamber has a plurality of elongated as well as spaced guide members (40) between the hot gas burners and the Web (W) are arranged above and below the same, with compressed air distributors (42) provided next to the guide members (40) 309822/0305 - 22 - are to blow compressed air into the heating chamber (34) so that so a dynamic flow of heated gases is created in the chamber (34) around the path (40). 309822/0305 COP *