JP5192988B2 - Continuous processing equipment for painted steel sheet - Google Patents

Description

The present invention relates to a continuous processing apparatus for coated steel sheets.

For example, in a continuous processing equipment for coated steel sheets that drys and bakes the coating film, the drying furnace that dries the coating film does not cause wrinkles on the coating film immediately after coating, preventing sudden boiling of the solvent in the coating film A horizontal catenary type radiant tube furnace that can control the temperature in the low temperature range while evaporating the solvent is used. A furnace can be used.
Here, in a continuous annealing apparatus for a steel sheet having a preheating furnace and a direct-fired heating furnace provided at the subsequent stage of the preheating furnace, the combustion exhaust gas generated in the direct-fired heating furnace is supplied to the preheating furnace to In order to reduce the fuel intensity of the preheating furnace and improve the thermal efficiency of the preheating furnace by heating the steel plate, the preheating furnace and the direct heating furnace are continuously arranged, and the upstream side of the direct heating furnace (combustion) Exhaust gas supply that supplies combustion exhaust gas generated in a direct-fired heating furnace between the downstream side of the exhaust gas flow and the downstream side of the preheating furnace (upstream side of the combustion exhaust gas flow) to the preheating furnace A gas exhaust pipe communicating with the chimney for exhausting the exhaust gas is provided on the upstream side of the preheating furnace (on the downstream side with respect to the combustion exhaust gas flow). It is recommended that a bypass pipe with a damper be connected in the middle of the pipe Is (e.g., see Patent Document 1). Also, in order to quickly discharge the combustion exhaust gas generated in the direct-fired heating furnace and operate the burner efficiently, the preheating furnace is directly connected to the direct-heating furnace, and the direct-fired type near the steel plate outlet of the preheating furnace It has been proposed to connect a portion close to the heating furnace (downstream side of the preheating furnace) and a direct-fired heating furnace with a flue gas flue and provide an outlet near the steel plate inlet of the preheating furnace (for example, Patent Document 2). reference).

JP-A-6-158182 Japanese Patent Laid-Open No. 11-12658

The inventions of Patent Documents 1 and 2 are for continuous annealing equipment, not for drying and baking of coated steel sheets. For this reason, in the inventions of Patent Documents 1 and 2, the entrance side of the preheating furnace is sealed with the seal roll, so that intrusion of outside air from the entrance side of the preheating furnace can be blocked. However, in a drying furnace (for example, a radiant tube furnace or a hot air blowing furnace) of a continuous processing apparatus for coated steel sheets, the steel sheet (paint film) cannot be touched until the coated film after coating is dried. For this reason, a seal roll is provided at the steel plate inlet of a drying furnace, for example, a radiant tube furnace, so that intrusion of outside air from the steel plate inlet cannot be blocked, and outside air enters the radiant tube furnace from the steel plate inlet of the radiant tube furnace. However, there arises a problem that the thermal efficiency of the radiant tube furnace is lowered. For this reason, it is necessary to close the door at the entrance of the steel plate of the radiant tube furnace to the limit that does not cause obstacles in the passage of the coated steel plate, but if the door is closed to the limit, the tension applied for conveying the coated steel plate When fluctuation occurs, the coated steel plate vibrates and collides with the door, causing a problem that the coating film is wrinkled or the steel plate is broken. In addition, when the direct heating furnace itself is provided with a connecting pipe that communicates with the chimney, the connection between the direct heating furnace and the chimney cannot be completely blocked even if the damper provided in the connecting pipe is closed. Due to the draft effect, the gas in the direct heating furnace and the radiant tube furnace is sucked. In this case, if the amount of combustion exhaust gas generated in the direct heating furnace is kept below the amount of gas sucked by the draft effect of the chimney when the damper of the connecting pipe is closed, the radiant tube is passed through the steel plate inlet of the radiant tube furnace. Outside air will be sucked into the furnace. Furthermore, regarding the combustion exhaust gas exhausted from the direct heating furnace by the draft effect, the amount of heat cannot be effectively used, and there is a problem that the thermal efficiency of the radiant tube furnace is lowered.

The present invention has been made in view of such circumstances, and suppresses the intrusion of outside air from the steel sheet inlet of the radiant tube furnace to the deep part of the radiant tube furnace to improve the thermal efficiency of the radiant tube furnace and avoid the occurrence of soot on the steel sheet. It aims at providing the continuous processing apparatus of the coated steel plate which can do.

The continuous processing apparatus of the coated steel sheet according to the present invention that meets the above-described object is provided in a horizontal catenary type radiant tube furnace that is supplied with a coated steel sheet and dries the coated film of the steel sheet, and a steel sheet outlet portion of the radiant tube furnace. In a continuous processing apparatus for a coated steel sheet, comprising a direct-fired heating furnace that is directly connected and receives the steel sheet discharged from the radiant tube furnace and bakes the coated film after drying on the steel sheet.
First exhaust means for exhausting combustion exhaust gas generated in the direct-fired heating furnace is provided immediately upstream of the steel sheet inlet of the radiant tube furnace.

In the coated steel sheet continuous processing apparatus according to the present invention, a duct that communicates with the first exhaust means and sucks outside air that has entered from the steel sheet inlet is provided immediately downstream of the steel sheet inlet of the radiant tube furnace. preferable.

In the continuous processing apparatus for a coated steel sheet according to the present invention, a second exhaust means is provided in the steel plate outlet of the direct-fired heating furnace so as to communicate with the steel plate outlet and exhaust the combustion exhaust gas in the steel plate outlet. A partition for suppressing the outflow of combustion exhaust gas in the direct-fired heating furnace by passing the steel plate through a portion of the steel plate outlet portion immediately upstream of the communication portion between the exhaust means of 2 and the steel plate outlet portion; preferable.
Moreover, the continuous processing apparatus of the coated steel plate concerning this invention can use the continuous processing apparatus of this coated steel plate as a drying and baking apparatus of a water-soluble coating film.
Here, the water-soluble coating film may be an insulating film of a directional silicon steel sheet.

In the coated steel sheet continuous processing apparatus according to the present invention, the first exhaust means for exhausting the combustion exhaust gas generated in the direct heating furnace is provided immediately upstream of the steel sheet inlet of the radiant tube furnace. When exhaust gas generated in a direct heating furnace is exhausted through a chimney communicating with the direct heating furnace itself, or the exhaust gas generated in the direct heating furnace is radiant tube downstream from the steel plate inlet of the radiant tube furnace Compared with the case of exhausting through a chimney communicating with the furnace part, it is possible to increase the flow rate of the combustion exhaust gas that passes through the steel plate inlet of the radiant tube furnace and is discharged to the outside. For this reason, conventionally, in order to suppress the outside air from entering the deep part of the radiant tube furnace, the door of the steel plate was closed to the lower limit opening degree that allows the steel plate to pass through. The opening degree of the door can be increased from the lower limit opening degree by an amount corresponding to an increase in the flow rate of the combustion gas passing through the steel plate inlet. As a result, even if the tension applied to the steel plate for the steel plate conveyance fluctuates and the catenary (pass line) of the steel plate fluctuates, the steel plate can be prevented from contacting the door provided at the steel plate inlet.

It goes without saying that the steel plate can be heated by the flow of the combustion exhaust gas that passes through the radiant tube furnace and is discharged by the first exhaust means, the fuel unit of the radiant tube furnace is reduced, and the thermal efficiency of the radiant tube furnace is improved. .
In addition, if the direct-fired heating furnace itself is provided with a connecting pipe that communicates with the chimney, the combustion exhaust gas amount of the direct-fired heating furnace will be less than the amount of gas drawn by the draft effect of the chimney even if the damper of the connecting pipe is closed However, in the present invention, since the direct-fired heating furnace itself is not provided with a connecting pipe communicating with the first exhaust means, this problem does not naturally occur. Further, since there is no exhaust of the combustion exhaust gas from the direct heating furnace itself to the connecting pipe communicating with the first exhaust means, the heat amount of the combustion exhaust gas is effectively used in the radians and the tube furnace, and the thermal efficiency of the radiant tube furnace is improved. Needless to say to raise it.

In the continuous processing apparatus for coated steel sheets according to the present invention, when a duct that communicates with the first exhaust means and sucks outside air that has entered from the steel sheet inlet is provided immediately downstream of the steel sheet inlet of the radiant tube furnace, Even if the outside air enters the radiant tube furnace from the steel sheet inlet, it can be exhausted by the first exhaust means through the duct, and the outside air hardly penetrates to the deep part of the radiant tube furnace.

In the continuous processing apparatus for a coated steel sheet according to the present invention, when the second exhaust means and the partition are provided at the steel sheet outlet of the direct heating furnace, it is possible to prevent the combustion exhaust gas from flowing out to the rear stage of the direct heating furnace.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is an explanatory view of a continuous processing apparatus for coated steel sheets according to one embodiment applied to an insulating film drying and baking apparatus for grain-oriented silicon steel sheets according to the present invention, and FIG. 2 is a continuous processing for the coated steel sheets. It is explanatory drawing of an effect | action of an apparatus.

As shown in FIG. 1, a coated steel sheet 11 is supplied to a coated steel sheet continuous treatment apparatus 10 according to an embodiment applied to an apparatus for drying and baking an insulating film of a grain-oriented silicon steel sheet according to the present invention. A horizontal catenary-type radiant tube furnace 12 for drying the coating film of the steel plate 11 and a steel plate outlet 13 of the radiant tube furnace 12 are directly connected to the steel plate 11 discharged from the radiant tube furnace 12 and dried. The steel plate 11 is baked, for example, has a horizontal catenary direct-fired heating furnace 14, and is generated in the direct-fired heating furnace 14 immediately upstream of the steel plate inlet 15 of the radiant tube furnace 12. A first exhaust means 16 is provided for exhausting the combustion exhaust gas flowing into the exhaust gas. Details will be described below.

The radiant tube furnace 12 is provided on the downstream side of the coater roll 17 that grips the steel plate 11 conveyed in the horizontal direction from above and below and applies a coating film to the steel plate 11. The radiant tube furnace 12 is provided with a steel plate inlet 15 through which the steel plate 11 coated with the coating film passes at the upstream end, and heats the steel plate 11 coated with the coating film to dry the coating film (not shown). A drying processing unit 19 that is disposed in parallel with the radiant tube and the coater roll 17 and includes a support roll 18 that supports the steel plate 11 in a pair with the coater roll 17, and is connected to the subsequent stage of the drying processing unit 19. A steel plate outlet 13 having a discharge roll 20 (disposed in parallel with the support roll 18) for determining the height position of the pass line of the steel plate 11 coated with the coating film discharged from the radiant tube furnace 12, and have. Here, the upstream end of the drying processing unit 19 in which the opening of the steel plate inlet 15 is formed is a pair that slides in the vertical direction on the outer surface of the upstream end to cover the opening. A door 23 having upper and lower partition members 21 and 22 is provided.

The first exhaust means 16 is provided with a suction port above the upstream side (near side) of the steel plate inlet 15 and sucks the combustion exhaust gas in the radiant tube furnace 12 to the outside of the radiant tube furnace 12 through the steel plate inlet 15. And a first chimney 25 connected to the combustion exhaust gas discharge duct 24. The first chimney 25 and the base of the first exhaust means 16 communicate with a portion of the ceiling of the drying processing unit 19 of the radiant tube furnace 12 and immediately downstream of the steel plate inlet 15, and the steel plate inlet 15 is connected to the front. A duct 26 having a suction port for sucking outside air that has entered the radiant tube furnace 12 is provided. Here, a first damper 27 is provided in the flue gas exhaust duct 24, and a second damper 28 is provided in the duct 26, and a hood 29 is attached to the edge of the suction port of the flue gas exhaust duct 24. ing.

The direct-fired heating furnace 14 is connected to the steel plate outlet portion 13 of the radiant tube furnace 12 and includes a steel plate inlet 30 that receives the steel plate 11 discharged from the steel plate outlet portion 13 and dried of the coating film at the upstream end portion, A baking processing unit that is provided in parallel with a burner (not shown) that heats the dried coating film and burns it onto the steel plate 11 and a discharge roll 20 and that supports the steel plate 11 in pairs with the discharge roll 20. 32 and a discharge roll 34 (support roll 31 and a support roll 31) that is connected to the subsequent stage of the baking processing unit 32 and determines the height position of the pass line of the steel plate 11 on which the coating film discharged from the direct heating furnace 14 is baked. And a steel plate outlet portion 35 provided in the inside thereof.

In addition, a second exhaust means 36 that communicates with the steel plate outlet portion 35 and exhausts the combustion exhaust gas in the steel plate outlet portion 35 is provided at an intermediate portion of the steel plate outlet portion 35 of the direct-fired heating furnace 14. The steel plate 11 on which the coating film is baked is passed through the portion of the steel plate outlet 35 on the upstream side of the intermediate portion 35 (immediately upstream of the communication portion between the second exhaust means 36 and the steel plate outlet 35). A partition 39 including partition walls 37 and 38 that are paired up and down to suppress outflow of combustion exhaust gas in the fire-type heating furnace 14 is provided. Here, the second exhaust means 36 is connected to an intermediate portion of the ceiling of the steel plate outlet portion 35 and exhaust gas exhaust duct 40 for exhausting the combustion exhaust gas in the steel plate outlet portion 35, and a second exhaust gas exhaust duct 40 connected to the exhaust gas exhaust duct 40. The chimney 41 is provided. The exhaust gas discharge duct 40 is provided with a third damper 42. Thereby, it is possible to prevent the combustion exhaust gas from flowing out to the subsequent stage of the direct-fired heating furnace 14.

Then, the effect | action of the continuous processing apparatus 10 of the coated steel plate which concerns on one embodiment of this invention is demonstrated.
As illustrated in FIG. 2, the radiant tube furnace 12 and the direct-fired heating furnace 14 are configured so that the inside of the radiant tube furnace 12 is 600 to 1000 ° C. and the inside of the direct-fired heating furnace 14 is 800 to 1200 ° C. When the second burner is used, the first damper 27 of the combustion exhaust gas exhaust duct 24 of the first exhaust means 16, the second damper 28 of the duct 26, and the third of the exhaust gas exhaust duct 40 of the second exhaust means 36 are used. When each of the dampers 42 is opened, a partition 39 for suppressing the outflow of the combustion exhaust gas is provided at the steel plate outlet 35 of the direct-fired heating furnace 14, so that the direct-fire type is achieved by the draft effect of the first chimney 25. Most of the combustion exhaust gas generated in the heating furnace 14 flows into the radiant tube furnace 12 from the direct-fired heating furnace 14 and enters the upstream side of the radiant tube furnace 12 (steel plate inlet 15). Only it flows.

For this reason, the steel plate 11 coated with the coating film passing through the radiant tube furnace 12 is heated by the combustion exhaust gas flowing into the radiant tube furnace 12, and the fuel intensity of the radiant tube furnace 12 is reduced, thereby reducing the radiant tube furnace. The thermal efficiency of 12 is improved. A part of the combustion exhaust gas that has moved to the upstream side of the radiant tube furnace 12 enters the duct 26 and is discharged from the first chimney 25.

Moreover, since the suction port of the combustion exhaust gas discharge duct 24 communicating with the first chimney 25 is disposed above the upstream side (outside) of the steel plate inlet 15 of the radiant tube furnace 12, the first Due to the draft effect of the chimney 25, the remainder of the combustion exhaust gas is sucked in the combustion exhaust gas discharge duct 24 and discharged from the first chimney 25. For example, a direct-fired heating furnace itself emit combustion exhaust gas at a flow rate of 250 Nm 3 / ^hr, from the bottom of the steel sheet inlet of the radiant tube furnace ambient air flows at a flow rate of 800 Nm 3 / ^hr, the steel sheet inlet of radiant tube furnace Compared with the conventional coated steel sheet continuous processing apparatus in which the outside air flows out from the upper part at a flow rate of 550 Nm ³ / hr, in the present invention, the outside air flows in from the lower part of the steel sheet inlet 15 of the radiant tube furnace 12 at a flow rate of 800 Nm ³ / hr. When the outside air flows out from the upper part of the steel plate inlet 15 of the radiant tube furnace 12 at a flow rate of 800 Nm ³ / hr, for example, if the furnace width of the radiant tube furnace 12 is 1.5 m, the opening height of the steel plate inlet 15 (The distance between the lower end surface of the upper partition member 21 and the upper end surface of the lower partition member 22) can be increased from 340 mm to 390 mm (15%). It became possible. A part of the flue gas generated in the direct-fired heating furnace 14 leaks into the steel plate outlet 35 of the direct-fired heating furnace 14 through the partition 39, but leaks into the steel plate outlet 35. The combustion exhaust gas is sucked by the exhaust gas exhaust duct 40 due to the draft effect of the second chimney 41 and discharged from the second chimney 41. For this reason, it is possible to prevent the combustion exhaust gas from flowing out to the subsequent stage (inside the furnace roll 43 side) of the direct-fired heating furnace 14.

Even if the combustion load of the direct-fired heating furnace 14 is reduced and the generation amount of combustion exhaust gas is reduced, the continuous processing apparatus 10 for coated steel sheets is provided with a connecting pipe communicating with the chimney in the direct-fired heating furnace 14 itself. In addition, a flue gas exhaust duct 24 and a duct 26 communicating with the first chimney 25 are provided before and after the steel plate inlet 15 of the radiant tube furnace 12 adjacent to the upstream side of the direct heating furnace 14. For this reason, even when the combustion load of the direct heating furnace 14 is reduced, a flow of combustion exhaust gas from the downstream side to the upstream side exists in the radiant tube furnace 12. This flow prevents the outside air from further entering into the deep portion of the radiant tube furnace 12, and the outside air that has entered is sucked together with the combustion exhaust gas by the duct 26 and is discharged from the first chimney 25.

For this reason, in the conventional technology in which the direct-fired heating furnace itself is provided with a connecting pipe communicating with the chimney, in order to suppress the intrusion of outside air toward the deep part of the radiant tube furnace 12, the combustion exhaust gas flows out from the steel plate inlet. Although it was necessary to ensure the generation of the amount of combustion exhaust gas that can be generated, the combustion load of the direct-fired heating furnace could not be reduced. Even if the combustion load of the radiant tube furnace 12 is reduced, the outside air that has entered the radiant tube furnace 12 due to the flow of the combustion exhaust gas flowing from the downstream side to the upstream side in the radiant tube furnace 12 further enters the deep portion of the radiant tube furnace 12. Since it is suppressed, it becomes possible to reduce the combustion load of the direct-fired heating furnace 14. As a result, it becomes possible to process the steel plate 11 with severe restrictions on the upper limit temperature in the direct-fired heating furnace 14.
When applying the continuous processing equipment for coated steel sheets according to this embodiment to dry and bake water-soluble coating film, even if the solvent in the coating film is water-soluble coating film, it can prevent solvent boiling It is possible to obtain a coated steel sheet provided with a high-quality coating film that suppresses the occurrence of uneven color.
Moreover, when applying the continuous processing apparatus of the coated steel plate of this Embodiment for drying and baking of the insulating film of a directional silicon steel plate, a directional silicon steel plate contacts the door 23 of the steel plate inlet 15 of the radiant tube furnace 12. In other words, the contact between the grain-oriented silicon steel sheet and the door 23 can prevent the insulation film from wrinkling and destroying the insulation, thereby ensuring an insulation film with uniform characteristics.

As described above, in the embodiment embodying the present invention, as shown in FIGS. 1 and 2, the steel tube outlet portion 13 of the radiant tube furnace 12 is provided with a region where the space between the upper and lower inner surfaces is narrowed, thereby providing the radiant tube furnace. Although the embodiment with a boundary between the direct-fired heating furnace 14 and the direct-fired heating furnace 14 is shown, a region where the distance between the upper and lower inner surfaces is narrowed is not provided in the steel plate outlet 13, and the radiant tube furnace 12 and the direct-fired heating furnace 14. Embodiments in which no boundary exists with the heating furnace 14 are also included in the present invention. Further, the present invention is not limited to the configurations described in the above-described embodiments, and includes other embodiments and modifications that can be considered within the scope of the matters described in the claims. .

It is explanatory drawing of the continuous processing apparatus of the coated steel plate which concerns on one Embodiment applied to the drying and baking apparatus of the insulating film of the grain-oriented silicon steel plate by this invention. It is explanatory drawing of an effect | action of the continuous processing apparatus of the same coated steel plate.

Explanation of symbols

10: Continuous treatment equipment for coated steel plate, 11: Steel plate, 12: Radiant tube furnace, 13: Steel plate outlet, 14: Direct-fired heating furnace, 15: Steel plate inlet, 16: First exhaust means, 17: Coater roll , 18: support roll, 19: drying processing unit, 20: discharge roll, 21: upper partition member, 22: lower partition member, 23: door, 24: combustion exhaust gas discharge duct, 25: first chimney, 26: duct , 27: first damper, 28: second damper, 29: hood, 30: steel plate inlet, 31: support roll, 32: baking processing unit, 34: discharge roll, 35: steel plate outlet, 36: second Exhaust means, 37, 38: partition wall, 39: partition, 40: exhaust gas exhaust duct, 41: second chimney, 42: third damper, 43: in-furnace roll

Claims (5)

A horizontal catenary-type radiant tube furnace that is supplied with a coated steel sheet and dries the coated film of the steel sheet, and is directly connected to a steel sheet outlet of the radiant tube furnace, and accepts the steel sheet discharged from the radiant tube furnace. In a continuous processing apparatus for a coated steel sheet, comprising a direct-fired heating furnace for baking the coated film after drying to the steel sheet,
A continuous processing apparatus for coated steel sheets, wherein a first exhaust means for exhausting combustion exhaust gas generated in the direct-fired heating furnace is provided immediately upstream of the steel sheet inlet of the radiant tube furnace. The continuous processing apparatus for coated steel sheets according to claim 1, wherein a duct is provided on the downstream side of the steel sheet inlet of the radiant tube furnace to communicate with the first exhaust means and suck outside air that has entered from the steel sheet inlet. The continuous processing apparatus of the coated steel plate characterized by the above-mentioned. The continuous processing apparatus of the coated steel plate of any one of Claim 1 and 2 WHEREIN: It communicates with this steel plate exit part in the steel plate exit part of the said direct-fired heating furnace, and exhausts the combustion exhaust gas in this steel plate exit part. 2 is provided, and the steel plate is passed through a portion of the steel plate outlet portion immediately upstream of the communication portion between the second exhaust means and the steel plate outlet portion. A continuous processing apparatus for coated steel sheets, characterized in that a partition for suppressing outflow is provided. The continuous processing apparatus for coated steel sheets according to any one of claims 1 to 3, wherein the continuous processing apparatus for coated steel sheets is a water-soluble coating film drying and baking apparatus. Processing equipment. The continuous processing apparatus for coated steel sheets according to claim 4, wherein the water-soluble coating film is an insulating film of a directional silicon steel sheet.

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