JP2022175794A - metal strip heat treatment furnace - Google Patents

Abstract

To provide a metal strip heat treatment furnace in which the amount of gas sprayed on a metal strip can be quickly changed while suppressing temperature changes inside the furnace where the metal strip is heat treated, and which has an extremely simple structure, high reliability and low facility cost.SOLUTION: A metal strip heat treatment furnace is equipped with: a furnace body 2 in which a metal strip W to be heat treated travels; a circulation duct system 5 comprising an internal duct 3 provided inside the furnace and an external duct 4 provided outside the furnace and communicated with the internal duct to circulate hot air inside the furnace; and a heater 6 provided in the external duct to heat gas. The internal duct is provided with a nozzle 8 for blowing hot air to the metal strip, and a communication opening 9 for discharging hot air into the furnace to reduce the amount of heating of the metal strip is openably/closably provided.SELECTED DRAWING: Figure 1

Description

INDUSTRIAL APPLICABILITY The present invention makes it possible to quickly change the amount of gas blown onto a metal strip while suppressing temperature changes inside the furnace body for heat-treating the metal strip, and at the same time, has an extremely simple structure, high reliability, and equipment. The present invention relates to a metal strip heat treatment furnace capable of reducing costs.

Conventionally, Patent Documents 1 to 3, for example, are known as metal strip heat treatment furnaces for heat-treating a metal strip running inside a furnace body.

The "vertical continuous annealing furnace for metal strip" of Patent Document 1 is provided with an indirect heating means and a heating rotating roll in the heating chamber, a preheating zone on the entrance side of the heating chamber, and a cooling zone on the exit side of the heating chamber. Annealing is performed by heating and transporting the metal strip while winding it around a heating rotating roll.

A suction duct is provided in the preheating zone of this vertical continuous annealing furnace for metal strip, and the atmosphere of the preheating zone sucked by a hot air circulation fan is heated to a predetermined temperature by a heater equipped with an indirect heating means such as an electric heater tube. It is heated and supplied to each hot air blowing nozzle through a supply duct to blow hot air onto the metal strip to preheat it.

The "strip material processing apparatus" of Patent Document 2 is configured by dividing the downstream side of a circulation duct having a heater in the width direction of the strip material, and arranging in the width direction of the strip material and blowing hot air onto the strip material. means, temperature measuring means for measuring the temperature distribution in the width direction of the strip material downstream of the hot air blowing means, and reducing the temperature difference in the width direction of the strip material according to the detection result of the temperature measuring means. and hot-air adjusting means for adjusting the amount of hot air to be blown by adjusting the opening of the damper for each hot-air blowing means.

The "shutter mechanism for strip-shaped work processing equipment" of Patent Document 3 is a nozzle having an injection port for blowing gas onto a traveling strip-shaped work, and between the nozzle and the strip-shaped work, it is possible to arrange a gap with respect to the nozzle. a shutter; and a moving device for moving the shutter to a first position where the shutter blocks the space between the nozzle and the strip-shaped work and a second position where the shutter does not block the space between the nozzle and the strip-shaped work, wherein the moving device comprises the shutter. to move a rod provided along the running direction of the belt-shaped work in the running direction.

In this belt-shaped work processing equipment, the heat treatment temperature of the belt-shaped work is lowered by blocking the hot air blowing to the traveling belt-shaped work with a shutter.

As in Patent Documents 1 to 3, the heat treatment of the running metal strip is performed by blowing hot air onto the metal strip, and the pattern of the treatment temperature varies depending on the material and thickness of the metal strip to be continuously treated. When the heat treatment temperature needs to be changed downward, the amount of hot air blowing on the metal strip is reduced.

In order to reduce the amount of hot air blown onto the metal strip, Patent Document 1 proposes to reduce the rotation speed of the hot-air circulation fan, and Patent Document 2 adjusts the opening of a damper provided for each hot-air blowing means. No. 5,200,000, a shutter is arranged between a nozzle for blowing hot air and a metal strip to block the hot air.

JP-A-11-61276 JP 2010-163634 A Japanese Patent No. 6332878

When lowering the heat treatment temperature, if the number of rotations of the hot air circulation fan is lowered as in Patent Document 1, it takes a long time to lower the temperature to the desired temperature.

In addition, since the amount of hot air itself is reduced, the temperature in the entire furnace is lowered, and the time required to raise the heat treatment temperature again becomes longer.

If it takes a long time to change the heat treatment temperature, there is a problem that the metal strips that have not been properly heat-treated are carried out of the furnace during that time, and the metal strips are wasted.

Providing a damper as in Cited Document 2 or providing a shutter as in Cited Document 3 complicates the structure. There was a problem that it was necessary to install a large number of the equipment, and the equipment cost increased.

The present invention has been devised in view of the above-mentioned conventional problems, and is capable of rapidly changing the amount of gas blown onto the metal strip while suppressing the temperature change inside the furnace body for heat-treating the metal strip. It is also an object of the present invention to provide a metal strip heat treatment furnace which is extremely simple in structure, highly reliable, and capable of reducing equipment costs.

A metal strip heat treatment furnace according to the present invention includes a furnace body in which a metal strip to be heat treated travels, an internal duct provided inside the furnace body, and an internal duct provided outside the furnace body and communicating with the internal duct. Composed of an external duct, it comprises a circulation duct system for circulating the gas inside the furnace body, a heating means provided in the external duct for heating the gas, and the internal duct has a nozzle for blowing the gas onto the metal strip. In addition, in order to reduce the amount of heating of the metal strip, a communicating hole for discharging the gas into the furnace body is provided so as to be openable and closable.

A metal strip heat treatment furnace according to the present invention includes a furnace body in which a metal strip to be heat treated travels, an internal duct provided inside the furnace body, and an internal duct provided outside the furnace body and communicating with the internal duct. Composed of external ducts, it comprises a circulation duct system for circulating the gas inside the furnace body, cooling means provided in the external ducts for cooling the gas, and the internal ducts having nozzles for blowing the gas onto the metal strip. In addition, in order to reduce the amount of cooling of the metal strip, a communicating hole for discharging the gas into the furnace body is provided so as to be openable and closable.

An opening/closing means for opening and closing the communication hole is provided, the communication hole being disposed at an appropriate position in the internal duct, the opening/closing means comprising an opening/closing member for freely opening and closing the communication hole, and an opening/closing member from the opening/closing member. It is characterized by comprising a transmission member extending to the outside of the furnace body, and an extendable cylinder provided outside the furnace body and engaged with the transmission member to move the open/close member.

The internal duct is supported by the furnace body via a support, and the communication hole is arranged at a position close to the support.

In the metal strip heat treatment furnace according to the present invention, it is possible to quickly change the amount of gas blown onto the metal strip while suppressing the temperature change inside the furnace body for heat-treating the metal strip, and the structure is extremely simple. , the reliability is high and the equipment cost can be reduced.

1 is a schematic side sectional view showing a preferred embodiment of a metal strip heat treatment furnace according to the present invention; FIG. The opening/closing means provided in the metal strip heat treatment furnace shown in FIG. 1 is shown, FIG. 2(A) is an enlarged view of the main part when the opening/closing means is closed, and FIG. 2(B) is the opening/closing means when it is open. Fig. 2 is an enlarged view of a main part of the time; A modification of the metal strip heat treatment furnace shown in FIG. 1 is shown, FIG. 3A is an enlarged view of the main part when the opening/closing means is closed, and FIG. It is a principal part enlarged view. FIG. 2 is an enlarged view of a main part showing another modification of the metal strip heat treatment furnace shown in FIG. 1;

A preferred embodiment of a metal strip heat treatment furnace according to the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, a metal strip heat treatment furnace (hereinafter referred to as a heat treatment furnace) 1 according to the present embodiment is fed from an opening 2a in the upper part of a furnace body 2 that is covered with a casing with a heat insulating material. This is a hot-air heat treatment furnace that blows heated gas as hot air onto the metal strip W that is sent out from the lower opening 2b and runs from top to bottom inside the furnace body 2 for heat treatment. The running direction of the metal strip W may be reversed from bottom to top.

The heat treatment furnace 1 has an internal duct 3 provided along the vertical direction inside the furnace body 2 and an external duct 3 provided along the vertical direction outside the furnace body 2 and communicating with the internal duct 3 via a communication pipe 5a. A circulation duct which has a duct 4 and circulates the hot air inside the furnace body 2 from the suction port 4a of the external duct 4 communicating with the inside of the furnace body 2 to the inside of the furnace body 2 through the external duct 4 and the internal duct 3. A system 5 is provided.

The external duct 4 is provided with a heater 6 as heating means for heating the gas into hot air. The circulation duct system 5 is also provided with a blower 7 for circulating the hot air from the external duct 4 to the internal duct 3 .

A pair of internal ducts 3 are provided facing the surface of the metal strip W and sandwiching the metal strip W from both sides in the thickness direction thereof, and are spaced apart from each other. That is, the metal strip W is run so as to pass between two internal ducts 3 facing each other. These internal ducts 3 are provided with their lower ends 3 a supported by the bottom 2 c of the furnace body 2 .

The inner duct 3 and the outer duct 4 are connected and communicated by a pair of upper and lower communication pipes 5a provided through the furnace wall 2d at their lower portions.

The external duct 4 is appropriately supported outside the furnace body 2 . A blower 7 is provided above the external duct 4 .

The upper portion of the external duct 4 communicates with the upper portion inside the furnace body 2 via the suction port 4a. A lower portion of the external duct 4 communicates with a lower portion of the internal duct 3 via a lower communicating pipe 5a. A heater 6 is provided at an intermediate position in the vertical direction of the external duct 4 .

The hot air generated by the heater 6 is circulated downward through the external duct 4 by the blower 7, flows through the lower communicating pipe 5a into the lower part of the internal duct 3, and then flows upward through the internal duct 3. The metal strip W is then circulated through the circulation duct system 5 to return to the upper portion of the external duct 4 through the suction port 4a.

In the illustrated example, a pair of circulation duct systems 5 are provided in a facing arrangement so as to sandwich the metal strip W from both sides in the thickness direction of the metal strip W.

However, only one external duct 4 having a heater 6 and a blower 7 is installed with the suction port 4a as one location, and the hot air is branched from the external duct 4 and both internal ducts 3 are provided facing each other. , one of the external ducts 4, the heaters 6 and the blowers 7 may be omitted.

The inner duct 3 is provided with a plurality of nozzles 8 arranged facing the metal strip W for blowing the hot air in the inner duct 3 onto the metal strip W.

Each nozzle 8 is formed in a slit-like shape elongated in the width direction of the metal strip W (the direction perpendicular to the running direction of the metal strip W), and is spaced apart from each other in the vertical direction.

The internal duct 3 provided inside the furnace body 2 has its lower end 3a supported by the bottom portion 2c of the furnace body 2, and thermally expands upward.

On the upper surface of the internal duct 3 where such thermal expansion occurs, a communicating hole 9 that can be opened to the inside of the furnace body 2 is provided as shown in FIGS. 1 and 2 . That is, the communication hole 9 is configured to be openable and closable by the opening/closing means 10 .

The opening/closing means 10 includes a plate-like opening/closing member 11 for freely opening and closing the communicating hole 9 disposed on the upper surface of the internal duct 3, and a rod-like member provided at the center of the upper surface of the opening/closing member 11 and extending upward. A transmission member 12, a first flange 13 provided at the upper end of the transmission member 12, an annular second flange 14 disposed below the first flange 13 and through which the transmission member 12 penetrates, and the first flange 13 and a tubular telescopic bellows 15 that seals between the second flange 14 and the second flange 14 from the outside.

The transmission member 12 is operated vertically. The communicating hole 9 is closed when the opening/closing member 11 contacts with the downward movement of the transmission member 12 , and is opened when the opening/closing member 11 is separated by the upward movement of the transmission member 12 .

The transmission member 12 is movably passed through the open/close member 11 through a through hole 2e provided in the furnace wall 2d above the internal duct 3, and protrudes above the furnace body 2 outside the furnace body 2. As shown in FIG.

The first flange 13 is attached to the upper end of the transmission member 12 outside the furnace body 2 . Accordingly, the first flange 13 is also moved vertically. The second flange 14 is fixed to the furnace body 2 via a mounting seat 23 outside the furnace body 2 .

A bellows 15 is joined to the peripheral edges of the first flange 13 and the second flange 14 . The bellows 15 is expanded and contracted when the transmission member 12 and the first flange 13 are vertically moved to approach or separate from the second flange 14 .

Further, the bellows 15 surrounds the space between the first flange 13 and the second flange 14 communicating with the inside of the furnace body 2 through the through hole 2e, thereby sealing the atmosphere inside the furnace body 2. As shown in FIG.

A push-up mechanism 16 that pushes up the transmission member of the opening/closing means 10 to open the communication hole 9 is provided on the furnace body 2 outside the furnace body 2 .

The push-up mechanism 16 has a vertically extendable cylinder 17 , a plate-shaped slide member 18 that is moved up and down by the cylinder 17 , and a guide 19 that guides the vertical movement of the slide member 18 .

The cylinder 17 is arranged side by side with the transmission member 12 so that its expansion/contraction direction is parallel to the extension direction of the transmission member 12 . A rod-shaped guide 19 is erected between the cylinder 17 and the transmission member 12 .

The slide member 18 is provided with a thrust bearing 20, and a guide 19 penetrates the thrust bearing 20 in the vertical direction. be.

The slide member 18 has a guide 19 interposed therebetween, and the cylinder rod 17a of the cylinder 17 is brought into contact with the lower end of the slide member 18 so that the cylinder rod 17a of the cylinder 17 can be freely contacted and separated. are spliced.

As shown in FIG. 2A, the cylinder rod 17a is separated from the slide member 18 when the cylinder rod 17a is contracted downward (the cylinder rod 17a is retracted into the cylinder 17). The opening 9 is closed by the open/close member 11 at this time.

Then, as shown in FIG. 2B, when the cylinder rod 17a is extended upward (the cylinder rod 17a is pulled out to the outside of the cylinder 17), it abuts against the slide member 18 and is engaged. Together with the slide member 18, the first flange 13 and the transmission member 12 of the opening/closing means 10 and the opening/closing member 11 are pushed upward.

When the open/close member 11 is pushed upward, the communication hole 9 of the internal duct 3 is opened, and part of the hot air in the internal duct 3 is discharged into the furnace body 2 .

At this time, the amount of hot air discharged can also be adjusted by stopping the extension operation of the cylinder rod 17a in the middle of the stroke and adjusting the degree of opening of the communication hole 9 by the opening/closing member 11 so as to be narrower than the fully open state. .

On the other hand, when the cylinder rod 17a is contracted, the slide member 18, which has been released from being pushed up, moves along the guide 19 to the first position by the lowering of the transmission member 12 due to its own weight and the weight of the first flange 13 and the open/close member 11. It descends together with the flange 13, and the communication opening 9 is closed by the open/close member 11 accordingly. Further, the cylinder rod 17a is separated from the slide member 18 as shown in FIG. 2(A).

That is, when the cylinder rod 17a is extended and raised, the communicating hole 9 is opened. 9 is closed.

As described above, the cylinder rod 17a and the slide member 18 are configured to be freely contactable and separable, and instead of closing the communication hole 9 by the action of gravity due to the weight of the opening/closing member 11, the cylinder rod 17a and the slide member 18 are moved. , so that the communication hole 9 can be opened and closed by moving the open/close member 11 up and down only by extending and retracting the cylinder rod 18a without relying on gravity.

In the heat treatment furnace 1 according to the present embodiment, the metal strip W is run while the cylinder rod 17a is lowered, that is, the communication hole 9 is closed, and the heater 6 and the blower 7 of the circulation duct system 5 are operated. Hot air is blown against the metal strip W from the nozzle 8 of the internal duct 3 to heat-treat the metal strip W at a predetermined temperature.

On the other hand, when the heating amount (heat treatment heat amount) of the metal strip W is to be reduced, the cylinder rod 17a is extended to open the communication hole 9. As shown in FIG. When the communication hole 9 is opened, part of the hot air in the internal duct 3 is discharged from the communication hole 9 to the inside of the furnace body 2, and the amount of hot air blown from the nozzle 8 to the metal strip W is reduced. The metal strip W can be heat-treated with a lower amount of heat than when the openings 9 are closed.

According to the heat treatment furnace 1 according to the present embodiment, the internal duct 3 is provided with the communication opening 9 for communicating the interior of the internal duct 3 with the interior of the furnace body 2, and the opening/closing means 10 for opening and closing the communication opening 9 is provided. Therefore, when the communicating hole 9 is closed by the opening/closing means 10, the amount of hot air blown from the nozzle 8 of the internal duct 3 to the metal strip W increases, and when the communicating hole 9 is opened by the opening/closing means 10, The hot air in the internal duct 3 is discharged from the communication hole 9, and the amount of hot air blown from the nozzle 8 to the metal strip W can be reduced.

With an extremely simple structure in which the internal duct 3 is provided with the communication hole 9 and the opening/closing means 10, high reliability and a reduction in equipment cost can be ensured, and only by opening the communication hole 9, Since it is not necessary to control the operation of the blower 7 and the heater 6, and part of the hot air is discharged from the internal duct 3 into the furnace body 2, the temperature change inside the furnace body 2 can be suppressed. The amount of hot air blown to the metal strip W can be quickly adjusted to reduce it, and the metal strip W can be prevented from being wasted.

The configuration in which the communication openings 9 are opened and closed by the opening and closing means 10 can reduce the blowing amount of hot air from all the nozzles 8 at once. , the structure is simple, and the equipment cost can be reduced.

Since the hot air is discharged into the furnace body 2 through the communication holes 9, the temperature inside the furnace body 2 can be maintained even if the heating amount is changed by changing the amount of the hot air blown onto the metal strip W. Therefore, it is possible to shorten the time required for closing the communicating hole 9 and returning the heating amount of the metal strip W to the original value, thereby suppressing generation of useless metal strip W.

Since the communication hole 9 of the internal duct 3, the opening/closing member 11 for opening and closing the communication hole 9, and the transmission member 12 passing through the through hole 2e are provided on the upper surface of the internal duct 3, they move according to the thermal expansion of the internal duct 3. The closed state of the communication hole 9 can be reliably maintained.

Since the push-up mechanism 16, including the cylinder 17, is provided outside the furnace body 2, damage due to heat can be prevented.

FIG. 3 shows a modification of the above embodiment. In the above embodiment, the case where the communication hole 9 is provided on the upper surface of the internal duct 3 has been described. 3 is provided laterally at a position close to the lower end 3a as a support portion supported by the bottom portion 2c of the furnace body 2, that is, at a position close to the starting point of thermal elongation. In this case, the communication opening 9 cannot be maintained in the closed state by the weight of the opening/closing member 11 and the like.

In this variant, the cylinder 17 is laterally extendable, and the cylinder rod 17a is moved so that the extending cylinder rod 17a abuts and the retracting cylinder rod 17a moves away as shown in FIG. 3(A). The transmission member 12 is pressed and urged toward the internal duct 3 side between the slide member 18 with which the transmission member 18 abuts so as to be freely contactable and detachable, and the spring seat 22 provided on the side of the furnace body 2 so as to face the slide member 18. A spring 21 is provided.

3B, when the cylinder rod 17a is extended, the cylinder rod 17a abuts and presses the slide member 18, thereby causing the transmission member 12 to move against the spring 21. The body 2 is pulled outward, and the opening/closing member 11 opens the communication hole 9 .

On the other hand, when the cylinder rod 17a is retracted, the cylinder rod 17a is separated from the slide member 18, and the transmission member 12 connected to the slide member 18 is moved by the spring 21 supported by the spring seat 22 on the furnace body 2 side. 2 is pushed inward, and the opening/closing member 11 closes the communication hole 9 as shown in FIG. 3(A).

FIG. 4 shows another modification of the above embodiment. In this modification, as in the modification of FIG. 3, the communicating hole 9 is provided sideways at a position close to the starting point of thermal expansion.

A sleeve 24 is provided on the outside of the furnace body 2 so as to communicate with the through hole 2e and through which the transmission member 12 is passed, and a ring provided on the sleeve 24 so as to be freely inserted and withdrawn inwardly. A body-shaped seal retainer 25 and a ring provided inside the sleeve 24 to surround the transmission member 12 and prevent hot air from leaking out of the furnace body 2 from the through hole 2e via the sleeve 24. A flexible sealing member 26 having a shape and a cylinder 17 which is provided on the furnace body 2 via a mounting seat 23 and in which a cylinder rod 17a which is laterally expanded and contracted is connected to the transmission member 12 is provided.

The seal member 26 is sandwiched between the seal retainer 25 and a stopper ring 24b provided integrally with the sleeve 24 inside the sleeve 24. - Flanges 24a and 25a are provided, which are connected by fastening means 27 such as nuts so as to be freely tightened and loosened.

When the fastening means 27 is tightened and the seal retainer 25 is advanced into the sleeve 24, the seal material 26 is compressed so as to be in pressure contact with the outer periphery of the transmission member 12, thereby ensuring airtightness inside the furnace body 2. . Further, the linear movement of the transmission member 12 passing through the sleeve 24 is also enhanced.

In this modification, when the cylinder rod 17a of the cylinder 17 is extended, the transmission member 12 is pushed into the furnace body 2, the communication opening 9 is closed by the open/close member 11, and when the cylinder rod 17a is contracted, The transmission member 12 is pulled out of the furnace body 2 and the opening/closing member 11 opens the communication hole 9 .

In these modifications, since the communication hole 9 is provided at a position close to the lower end 3a that is the support portion of the internal duct 3, even if the internal duct 3 thermally expands, the position of the communication hole 9 moves. It can be opened and closed properly by suppressing this.

It is a matter of course that even these modified examples have the same effect as the above-described embodiment.

In the above-described embodiment and modification, the case where the metal strip W is heat-treated by hot air obtained by heating the gas with the heater 6 has been described. Even when a cooler is provided as a means and the metal strip W is cooled by cold air obtained by cooling the gas with the cooler, the amount of cooling of the metal strip W can be adjusted and the same effect can be achieved. Of course.

The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit and interpret the present invention. The present invention can be modified and improved without departing from its spirit, and it goes without saying that the present invention includes equivalents thereof.

REFERENCE SIGNS LIST 1 metal strip heat treatment furnace 2 furnace body 2a upper opening of furnace body 2b lower opening of furnace body 2c bottom 2d furnace wall 2e through hole 3 internal duct 3a lower end of internal duct 4 external duct 4a suction port 5 circulation duct system 5a communicating pipe 6 Heater 7 Blower 8 Nozzle 9 Communication hole 10 Opening/closing means 11 Opening/closing member 12 Transmission member 13 First flange 14 Second flange 15 Bellows 16 Lifting mechanism 17 Cylinder 17a Cylinder rod 18 Slide member 19 Guide 20 Thrust bearing 21 Spring 22 Spring seat 23 Mounting seat 24 Sleeve 24a Flange 24b Stopper ring 25 Seal retainer 25a Flange 26 Seal material 27 Fastening means W Metal strip

Claims (4)

a furnace body in which the metal strip to be heat-treated runs;
a circulation duct system for circulating gas inside the furnace body, comprising an internal duct provided inside the furnace body and an external duct provided outside the furnace body and communicating with the internal duct;
A heating means provided in the external duct for heating the gas,
The internal duct is provided with a nozzle for blowing gas onto the metal strip, and is provided with a communication hole that can be opened and closed to discharge the gas into the furnace body in order to reduce the amount of heating of the metal strip. metal strip heat treatment furnace. a furnace body in which the metal strip to be heat-treated runs;
a circulation duct system for circulating gas inside the furnace body, comprising an internal duct provided inside the furnace body and an external duct provided outside the furnace body and communicating with the internal duct;
A cooling means provided in the external duct for cooling the gas,
The internal duct is provided with a nozzle for blowing gas onto the metal strip, and is provided with a communication hole that can be opened and closed to discharge the gas into the furnace body in order to reduce the amount of cooling of the metal strip. metal strip heat treatment furnace. An opening and closing means for opening and closing the communication hole,
The communication opening is arranged at an appropriate location of the internal duct,
The opening/closing means includes an opening/closing member for freely opening and closing the communication hole, a transmission member extending from the opening/closing member to the outside of the furnace body, and a transmission member provided outside the furnace body and engaged with the transmission member. 3. The metal strip heat treatment furnace according to claim 1, further comprising a telescopic cylinder for moving the opening and closing member. The internal duct is supported by the furnace body via a support, and the communicating hole is arranged at a position close to the support. metal strip heat treatment furnace.

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