JP2010281555A5 - - Google Patents

Description

Heat treatment furnace

The present invention relates to a thermal processing furnace, to heat treatment furnace especially high thermal efficiency.

  Patent Document 1 discloses a continuous heat treatment furnace. This continuous heat treatment furnace has an axial fan provided at the upper part of the furnace body, a heating device provided below it, a slit plate provided below it, and a beam provided below it (a workpiece is suspended on the beam). To be lowered). According to the continuous heat treatment furnace described in Patent Document 1, it is possible to save human power as much as possible, improve productivity, uniform work quality, and improve thermal efficiency.

  Patent document 2 discloses a hot-air circulating furnace. The hot air circulating furnace includes a furnace body having a heat source and a rotary hearth, an annular mounting table, an axial fan, and an annular partition. The mounting table is provided along the peripheral wall of the furnace body at a portion near the outer peripheral side of the rotary hearth. A workpiece is placed on the mounting table so that it can be carried in and out in the radial direction. A circulating flow can pass vertically through the mounting table. The axial fan is provided near the ceiling of the furnace body. The axial fan sucks hot gas from its outer peripheral direction toward the center and discharges it toward the rotary hearth. The annular partition separates the inside of the furnace into an outer peripheral side region where the mounting table is installed and an inner side region inside it. The annular partition defines a passage where the circulating flow is reversed near the rotary hearth and the ceiling of the furnace body. According to the hot-air circulating furnace described in Patent Document 2, the processing amount can be increased while being small.

Japanese Patent Laid-Open No. 51-131408 JP 2004-257658 A

  However, the continuous heat treatment furnaces disclosed in Patent Document 1 and Patent Document 2 have a problem that there is room for improvement in thermal efficiency.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a heat treatment furnace capable of increasing the thermal efficiency.

  The heat treatment furnace of the present invention will be described with reference to the drawings. Note that the use of the reference numerals in the figure in this column is intended to assist understanding of the contents of the invention, and is not intended to limit the contents to the illustrated range.

According to an aspect of the present invention, the heat treatment furnace includes a furnace body 10, a hearth 12, a blower 14, a cylindrical partition 16, and a shelf 18. The furnace body 10 has openings 40 and 42 with doors. The openings 40 and 42 with doors are for taking the workpiece 100 in and out. The hearth 12 is disposed at the lower part of the furnace body 10. The hearth 12 rotates in the horizontal direction. The blower 14 is disposed inside the furnace body 10 and above the hearth 12. The cylindrical partition 16 is disposed inside the furnace body 10 and between the blower 14 and the hearth 12. The shelf 18 is attached to the hearth 12. The shelf 18 is for placing a workpiece. A space between the blower 14 and the hearth 12 is partitioned by a cylindrical partition 16 into a central space 50 and an outer peripheral space 52. A space 50 in the central portion is configured as a gas inlet to the blower 14. Wind discharged from the blower 14 is passed is fed into the space 5 2 of the outer peripheral portion. Shelves 18, attached to the hearth 12 to be placed in the space 5 2 of the outer peripheral portion, with the rotation of the hearth 12, is pivoted in the space 52 of the outer peripheral portion. In the position below the cylindrical partition 16, the guide portion 20 that guides the wind in the outer peripheral space 52 into the central space 50 is arranged. A heating device 22 that heats the air discharged from the blower 14 is disposed at a position above the cylindrical partition 16. Of the outer peripheral space 52 above the shelf 18, the outer peripheral space 52 is more heated than the outer heating portion 80 in the outer peripheral space 52 than the portion 82 in the outer peripheral space 52 that is in the soaking zone. A distributor 24 that distributes the air heated by the heating device 22 is disposed so as to supply heat.

  The wind that has passed through the outer peripheral space 52 is guided by the guide 20 to the central space 50. The blower 14 sucks gas from the space 50 in the central portion and sends the air to the space 52 in the outer peripheral portion. The heating device 22 heats the wind. The distribution unit 24 distributes the air heated by the heating device 22 so as to supply more heat to the portion 80 that becomes the heating zone than the portion 82 that becomes soaking. Meanwhile, the shelf 18 is swung in the outer peripheral space 52 as the hearth 12 rotates. Thereby, heat is given to the workpiece 100 placed on the shelf 18 through the wind. The heat given to the workpiece 100 in the portion 80 that becomes the heating zone is larger than the heat given to the workpiece 100 in the portion 82 that becomes the soaking zone. Since the low temperature workpiece 100 immediately after being put in the furnace body 10 is given more heat than when the predetermined temperature is reached, it is expended for the temperature increase in the portion 80 that becomes the heating zone. Insufficient heat is generated, and the workpiece 100 is less likely to be heated more than necessary in the soaking zone 82. As a result, the thermal efficiency is increased.

  Moreover, it is desirable that the distribution unit 24 described above includes a first wind supply unit 62 and a second wind supply unit 64. The 1st wind supply part 62 is arrange | positioned on the part 80 used as a heating zone. The 2nd wind supply part 64 is arrange | positioned on the part 82 used as soaking. The second wind supply unit 64 has a smaller amount of wind supply per unit time than the first wind supply unit 62.

  Alternatively, it is desirable that the first wind supply unit 62 described above is a member having a hole. In this case, the second wind supply unit 64 is a member having a hole and having a smaller sum of opening areas of the holes than the first wind supply unit 62.

  Or it is desirable for the distribution part 24 mentioned above to further have the members 66 and 68 arrange | positioned on the openings 40 and 42 with a door in the space 52 of an outer peripheral part. In this case, the members 66 and 68 disposed on the openings 40 and 42 with doors are disposed so as to form a gap with the inner peripheral surface of the furnace body 10.

  By forming the gap, an air curtain is formed in a portion of the inner peripheral surface of the furnace body 10 where the openings 40 and 42 are provided. This air curtain suppresses intrusion of outside air from the openings 40 and 42. Since intrusion of outside air is suppressed, a temperature drop when the doors of the openings 40 and 42 are opened and closed is reduced. Since the temperature drop is reduced, heat loss due to the opening and closing of the doors of the openings 40 and 42 is also reduced. Since heat loss is reduced, the thermal efficiency can be further increased.

  As described above, according to the heat treatment furnace according to the present invention, the thermal efficiency can be increased.

It is a vertical sectional view of the heat treatment furnace concerning the embodiment of the present invention. It is a horizontal sectional view of the heat treatment furnace concerning the embodiment of the present invention. It is a conceptual diagram which shows arrangement | positioning of each area concerning the internal space of the furnace body concerning embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1 and FIG. 2, the structure of the heat processing furnace concerning this embodiment is demonstrated. The heat treatment furnace according to this embodiment includes a furnace body 10, a hearth 12, a blower 14, a cylindrical partition 16, a shelf 18, an induction unit 20, a heating device 22, a distribution unit 24, and a suction unit. A control plate 26 and a sand removal plate 28 are provided.

  The furnace body 10 has an inlet opening 40 and an outlet opening 42. A door is attached to each of the inlet opening 40 and the outlet opening 42. The number of these doors is determined according to how many shelves 18 are provided.

  The hearth 12 is disposed below the furnace body 10 so as to face the inside of the furnace body 10. The hearth 12 rotates in the horizontal direction in the furnace body 10. However, in the present embodiment, various members (for example, shelves) attached to the workpiece 100 and the hearth 12 inside the furnace body 10 and members (for example, the cylindrical partition 16 and the distributing unit 24) disposed therein. 18), it is considered that the hearth 12 is rotating in the horizontal direction even if it is not horizontal in the strict sense. The blower 14 sucks gas and sends wind. In this embodiment, an axial fan is attached as the blower 14.

  The cylindrical partition 16 partitions the interior of the furnace body 10 into a central space 50 and an outer peripheral space 52. With reference to FIG. 3, the space 50 in the central portion and the space 52 in the outer peripheral portion will be described. The central portion space 50 is the middle portion of the furnace body 10. The outer peripheral space 52 is a portion surrounding the central space 50 in the furnace body 10. In the present embodiment, the blower 14 sucks gas from the space 50 in the central portion of the furnace body 10 and sends the wind to the space 52 in the outer peripheral portion.

  The outer peripheral space 52 is divided into a first section 80, a second section 82, a third section 84, and a fourth section 86. The first section 80 is a section disposed on the rotational direction side of the hearth 12 with respect to the inlet opening 40. In this embodiment, this part becomes a heating zone. The second section 82 is a section that continues from the first section 80 at the end of the hearth 12 in the rotation direction among both ends of the first section 80. In this embodiment, this part is a soaking zone. In the present embodiment, the end portion of the second section 82 faces the outlet opening 42. The third section 84 is a section following the second section 82 at the end of the hearth 12 in the rotation direction among both ends of the second section 82. The position of the third section 84 is between the inlet opening 40 and the outlet opening 42. The fourth section 86 is a section facing the inlet opening 40. The fourth section 86 continues to the third section 84 at the end on the rotational direction side of the hearth 12 among both ends of the third section 84.

  With reference to FIGS. 1 and 2 again, other parts of the heat treatment furnace according to the present embodiment will be described. The shelf 18 is attached to the hearth 12. A workpiece 100 is placed on the shelf 18. Accordingly, the shelf 18 rotates in the horizontal direction together with the hearth 12. In this embodiment, six shelves 18 are provided.

  The induction unit 20 is also attached to the hearth 12. The guiding portion 20 guides the wind that has descended from the outer peripheral space 52 to the central space 50.

  The heating device 22 is disposed above the blower device 14. The heating device 22 heats the wind sent by the blower device 14. In this embodiment, two combustion burners are attached as the heating device 22.

  The distribution unit 24 is disposed above the shelf 18 in the outer peripheral space 52. The distribution unit 24 distributes the air heated by the heating device 22. The air heated by the heating device 22 is distributed so that more heat is supplied to the first section 80 than in the second section 82.

  The distribution unit 24 will be described in detail. As is clear from FIG. 1 and FIG. 2, the distribution unit 24 is attached so as to leave a slight gap with the inner periphery of the furnace body 10. For this reason, the part arrange | positioned on the 4th area 86 (as a result on the inlet opening 40) among the distribution parts 24 is arrange | positioned so that a clearance gap may be formed between the inner peripheral surfaces of the furnace body 10. FIG. It becomes. Thereby, a part of the wind sent by the blower 14 descends through the gap between the inner peripheral surface of the furnace body 10 and the distribution unit 24.

  The distribution unit 24 includes a first wind supply unit 62, a second wind supply unit 64, a first shielding unit 66, and a second shielding unit 68. The first wind supply unit 62 is disposed on the first section 80. In the case of the present embodiment, the first wind supply unit 62 is three plates. These plates have large holes. Since the larger holes are made, most of the hot air sent by the blower 14 is distributed to the first section 80. Since most of the hot air is dispensed, the underlying workpiece 100 is rapidly heated. As a result, the first section 80 becomes a heating zone. The 2nd wind supply part 64 is arrange | positioned on the 2nd area. In the case of this embodiment, the 2nd wind supply part 64 is seven boards. These plates have small holes. Since the small hole is made, the hot air sent from the blower 14 is not distributed to the second section 82 so much. Since hot air is not distributed much, the temperature is kept constant in the second section 82. As a result, the second section 82 becomes a soaking zone. In the present embodiment, the number of holes per unit area of the first wind supply unit 62 and the second wind supply unit 64 is the same. The size of the board which comprises them is also the same. In the present embodiment, the first wind supply unit 62 and the second wind supply unit 64 differ only in the size of the holes. Thereby, in this embodiment, the sum of the opening area of the hole of the board which comprises the 2nd wind supply part 64 is less than the sum of the opening area of the hole of the board which comprises the 1st wind supply part 62, Become. The first shielding part 66 is disposed on the third section 84. The second shielding part 68 is disposed on the fourth section 86. In the case of this embodiment, the 1st shielding part 66 is one board. The same applies to the second shielding part 68. The first shielding part 66 and the second shielding part 68 are also provided with holes. The number of those holes per unit area is half that of the second wind supply unit 64. The sizes of these holes are the same as those of the second wind supply unit 64. Because of such a structure, most of the wind sent by the blower 14 is blocked in these areas. However, even in these regions, a gap is provided between the inner periphery of the furnace body 10. Furthermore, the first shielding part 66 and the second shielding part 68 are provided with holes, although not as much as the second wind supply part 64. Therefore, the wind distributed to these regions falls down through the gap between the inner peripheral surface of the furnace body 10 and the distribution unit 24. By passing through the gap, an air curtain is formed on the inner peripheral surface of the furnace body 10 around the inlet opening 40. In the present embodiment, an air curtain is formed not only around the inlet opening 40 but also on the entire inner peripheral surface of the furnace body 10.

  The suction control plate 26 is attached to the hearth 12 so as to be disposed just below the space 52 in the outer peripheral portion. A sand removal plate 28 is also attached to the hearth 12. The sand removal plate 28 is attached to the inside of the guide portion 20. The sand removing plate 28 scrapes the sand from the wind inside the guiding portion 20. The crushed sand is discharged from a discharge port provided at the bottom of the hearth 12.

  A method of using the heat treatment furnace according to the present embodiment based on the above configuration will be described.

  The door of the entrance opening 40 is opened, and the workpiece 100 is inserted into the furnace body 10 from the outside of the heat treatment furnace using an appropriate jig. As described above, an air curtain is formed on the entire inner peripheral surface of the furnace body 10. This air curtain prevents outside air from entering when the door is opened.

  When the workpiece 100 is inserted, the door of the entrance opening 40 is closed. The hearth 12 rotates in a counterclockwise direction when the heat treatment furnace according to the present embodiment is viewed from above. When the hearth 12 rotates, the shelf 18 also rotates. When the shelf 18 rotates, the workpiece 100 placed thereon also rotates. As a result, the workpiece 100 sequentially moves from the heating zone to the soaking zone.

  Since the first wind supply unit 62 of the distribution unit 24 faces the heating zone, a large amount of wind hits the workpiece 100. Thereby, the workpiece 100 is heated rapidly. After passing through the heating zone, the workpiece 100 enters the soaking zone. The second wind supply unit 64 of the distribution unit 24 is opposed to the soaking zone. There is not much wind from the second wind supply unit 64. As a result, the temperature of the soaking zone is kept almost constant. Thereafter, the workpiece 100 enters the third section 84. Then, the door of the exit opening 42 is opened, and the workpiece 100 is taken out from the inside of the furnace body 10 with an appropriate jig. Thereby, the heat treatment with respect to the workpiece 100 is completed. Incidentally, as is apparent from the above description, in the present embodiment, an air curtain is formed on the entire inner peripheral surface of the furnace body 10. This air curtain prevents outside air from entering when the door is opened.

  As described above, according to the heat treatment furnace of this embodiment, heat treatment can be performed in one furnace. At that time, since heat is distributed through the distribution unit 24, heat can be distributed without waste even if a plurality of heat sources are not provided. Moreover, the furnace can be divided into a heating zone and a soaking zone by a simple structure. Furthermore, since the air curtain is formed in the inner peripheral surface of the furnace body 10, the heat treatment furnace according to the present embodiment can suppress the intrusion of outside air. Thereby, since heat loss is reduced, it is possible to reduce energy consumed for heat treatment.

  This point will be specifically described. The continuous heat treatment furnace as disclosed in Patent Document 1 consumes heat to heat the beam that suspends the workpiece. The heat loss increases accordingly. In a hot-air circulating furnace as disclosed in Patent Document 2, the temperature in the furnace decreases due to the intrusion of outside air when opening and closing the entrance and exit doors. As the temperature in the furnace decreases, the temperature rise of the workpiece in the heating zone will not be successful. The temperature of the workpiece in the soaking zone will not reach the expected temperature. This will adversely affect the quality of the workpiece.

  On the other hand, since the heat treatment furnace according to the present embodiment places the workpiece 100 on the shelf 18, once the temperature of the shelf 18 becomes high, the heat is hardly consumed to raise the temperature of the shelf 18 thereafter. In the heat treatment furnace according to the present embodiment, an air curtain is formed by blowing air from the gap between the inner peripheral surface of the furnace body 10 and the distribution unit 24. Since the air curtain is formed, intrusion of outside air is suppressed. Since the penetration of outside air is suppressed, the temperature inside the furnace is less likely to drop due to the entry of outside air. Since the temperature in the furnace decreases less, heat loss can be suppressed and the quality of the workpiece 100 can be kept good.

  In the heat treatment furnace according to the present embodiment, the sand removal plate 28 is attached to the inside of the induction unit 20. Since the sand removal plate 28 is attached to the inside of the guide portion 20, even if the casting sand remains in the workpiece 100, the sand is removed from the wind circulating inside the furnace body 10. . Since the sand is removed, the sand is less likely to wear the equipment in the furnace.

  Furthermore, the heat treatment furnace according to the present embodiment has a structure in which the wind rises through the space 50 in the central portion and the wind is sucked by the blower 14. By having such a structure, an effect that wear in the furnace hardly occurs can be obtained. Abrasion is less likely because sand is well removed from the wind. The reason why the sand is often removed from the wind is that the sand sinks due to gravity when the wind goes up the space 50 in the central portion.

  The embodiments disclosed herein are illustrative in all respects. The scope of the present invention is not limited based on the above-described embodiment, and various design changes may be made without departing from the spirit of the present invention.

  For example, a heat source such as an electric heater may be attached as the heating device 22 instead of the combustion burner. The combustion burner can be arbitrarily determined according to the number of workpieces 100.

  Moreover, the distribution part 24 may have a slit instead of a hole. Furthermore, the first wind supply unit 62 and the second wind supply unit 64 of the distribution unit 24 may have different numbers per unit area as well as the size of the holes and slits.

  If it is not necessary to form an air curtain, the outer periphery of the distribution unit 24 may be in close contact with the inner peripheral surface of the furnace body 10. When an air curtain is formed only in one of the inlet opening 40 and the outlet opening 42, or when an air curtain is formed only in the inlet opening 40 and the outlet opening 42, the configuration of the distribution unit 24 will be described below. It may be something like this. The configuration is that a notch is provided in a member that constitutes the distribution unit 24 and is disposed at a location where an air curtain is to be formed. The place where the notch is provided is a place in contact with the inner peripheral surface of the furnace body 10. Thereby, a wind will flow along the internal peripheral surface of the furnace body 10 only in the location which wants to form an air curtain.

  Further, the distribution unit 24 may be a structure such as a box instead of a plurality of plates. In this case, the member which comprises the distribution part 24 may have the pipe | tube through which wind passes instead of a hole.

  In addition, the number of shelves 18 is not particularly limited. The number of shelves 18 may be 5 or less, or 7 or more. The number of doors respectively attached to the inlet opening 40 and the outlet opening 42 is not particularly limited. For example, you may attach a big door so that the workpiece 100 can be taken in / out from the shelf 18 for two steps. In this case, the number of doors is reduced.

  Moreover, the first shielding part 66 and the second shielding part 68 do not need to be provided with holes.

DESCRIPTION OF SYMBOLS 10 Furnace 12 Furnace 14 Air blower 16 Cylindrical partition 18 Shelf 20 Guidance part 22 Heating device 24 Distribution part 26 Suction control board 28 Sand removal board 40 Inlet opening 42 Outlet opening 50 Central part space 52 Outer part space 62 First 1 wind supply part 64 2nd wind supply part 66 1st shielding part 68 2nd shielding part 80 1st section 82 2nd section 84 3rd section 86 4th section 100 Workpiece

Claims (4)

A furnace body having an opening with a door for taking in and out the workpiece;
A hearth disposed at the bottom of the furnace body and rotating in a horizontal direction;
An air blower disposed inside the furnace body and above the hearth;
A cylindrical partition disposed inside the furnace body and between the blower and the hearth;
A heat treatment furnace attached to the hearth and provided with a shelf for placing a workpiece,
A space between the blower and the hearth is partitioned into a central space and an outer peripheral space by the cylindrical partition, and the central space is configured as a gas suction port to the blower. And the wind exhausted from the blower is sent to the space of the outer peripheral portion and passed therethrough,
The shelf is attached to the hearth so as to be arranged in the space of the outer peripheral portion, and is rotated in the space of the outer peripheral portion with the rotation of the hearth,
At a position below the cylindrical partition, a guide portion that guides wind in the space of the outer peripheral portion into the space of the central portion is disposed,
At a position above the cylindrical partition, a heating device for heating the wind discharged from the blower is disposed,
The upper part of the outer peripheral part above the shelf is supplied with more heat than the part of the outer peripheral part in the soaking zone to the part of the outer peripheral part that becomes a heating zone. A heat treatment furnace is provided, wherein a distribution unit for distributing the air heated by the heating device is disposed. The distributor is
A first wind supply unit disposed on a portion to be the heating zone;
It has a 2nd wind supply part arrange | positioned on the part used as the soaking zone, and the supply amount of the said wind per unit time is smaller than the said 1st wind supply part, It is characterized by the above-mentioned. The heat treatment furnace described. The first wind supply part is a member having a hole;
The heat treatment furnace according to claim 2, wherein the second wind supply unit is a member having a hole and having a smaller sum of opening areas of the holes than the first wind supply unit. The distribution part further has a member arranged on the opening with the door in the space of the outer peripheral portion,
The heat treatment furnace according to claim 2, wherein a member disposed on the opening with the door is disposed so as to form a gap with an inner peripheral surface of the furnace body.