JP2582299B2 - Fluidized bed heat treatment furnace for wires - Google Patents

Description

The present invention relates to a fluidized bed heat treatment furnace for wires.

[Conventional technology and its technical problems]

Hard steel wires and piano wires represented by wire ropes, steel cords, PC steel wires, and the like are obtained by cold-working (drawing) hot-rolled wires with dies and rolls. Since these products require high mechanical properties and fatigue properties, heat treatment and cold working methods are important points in addition to the composition of the materials. Drawing is usually performed in a number of times, and the heat treatment called patenting is performed in drawing when the degree of work increases and the tensile strength and hardness increase.

As a heating means used for this patenting, especially for strand-type patenting, a direct-fired furnace that directly heats a passing line with a heating flame, and an indirect heating furnace that heats a wire passing through a muffle from outside the muffle,
From the viewpoint of heating efficiency and economy, alumina, zircon sand,
Recently, fluidized bed heating furnaces which use fluidized particles of silicon carbide, silicon iron or the like and allow a wire to pass through the bed have been recently used in many cases. The following types of fluidized bed heating furnaces are conventionally known.

As shown in FIG. 6 (a), the solid particles a are arranged in the retort above the rectifying member b having a porous structure, and the blast air introduced into the chamber c below the rectifying member is blown out from the rectifying member b so as to be solid particles. The fluidized bed is heated to a predetermined temperature by indirectly applying heat to the solid particles a from a heating source d provided on both side walls of the furnace (indirect heating method).

As shown in FIG. 6 (b), the chamber c is a gas combustion chamber, in which the burner d burns the gas, and the high temperature combustion gas is ejected from the rectifying member b to obtain fluidization and heating of the solid particles a. As shown in FIG. 6 (c), air is supplied to the chamber c to fluidize the solid particles, and the gas distribution pipe e is placed just above the straightening member b. The heating gas is supplied to the fluidized bed f, and the heating gas and the air are mixed and burned in the fluidized bed f (heating inside the fluidized bed). As shown in FIG. A method in which air is supplied to a chamber c to fluidize solid particles, and a combustion gas is directly blown against a fluidized bed f by a burner d attached to a furnace body to heat the fluidized bed f (a fluidized bed upper direct heating method). As shown in FIG. 6 (e), the combustion cylinder g
A burner d is attached to the outer end of the furnace to burn a mixture of the heating gas and air in the combustion cylinder g, and feed the flowing air downstream of the burner to dilute the flowing air. In order to obtain fluidity and heating by mixing (air gas heating method with internal combustion in a fluidized bed) However, in these prior arts, the rectifying member b for maintaining the flow of the fixed particles a is constantly exposed to the fluidized bed temperature. Is done. For this reason, when used in a temperature range exceeding the red heat range, the life of the nozzles, perforated plates, woven fabric, perforated combustion cylinders, etc. that constitute the straightening member is short, and clogging may occur due to oxidation and oxides. Cheap. Therefore, the heating temperature is actually limited to a maximum of 700 ° C., and it becomes difficult to perform heating at a higher temperature, and there has been a problem that the heating time becomes longer. Further, since complicated maintenance and inspection are required, there is a problem that running costs are increased and downtime is lengthened. Furthermore, since the movement of the solid particles tends to fluctuate due to the clogging or the like, it is difficult to stably obtain a fluidized bed shape from a low temperature to a high temperature, and there is a problem that high-quality heat treatment cannot be performed. Furthermore, since the entire fluidized bed is heated in the furnace width direction, there is a problem that it is not possible to form fluidization conditions according to the throughput per unit time and to carry out efficient fluidized heating.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to continuously obtain a stable fluidized bed shape in a region exceeding the red heat temperature range. Fluidized bed of wire rods that can perform quality heat treatment, has a long life even at high temperature heat treatment exceeding 1000 ° C, and can omit complicated work such as clogging of rectifying means and maintenance and inspection caused by this. An object of the present invention is to provide a heat treatment furnace.

It is another object of the present invention to provide a fluidized bed heat treatment furnace for wire rods capable of forming fluidization conditions according to the throughput per unit time and performing efficient fluidized heating.

[Means for solving the problem]

In order to achieve the above object, the present invention relates to a furnace in which solid particles are accommodated, heated and heated by flowing gas through a wire rod to perform heat treatment. A gas chamber for movement and a gas chamber for flow and heating are defined and the upper partition wall is filled with granules, and one of the two partition walls has a base end connected to the main flow gas chamber and an ejection hole at the front end. Is a plurality of distribution nozzles reaching a position below the wire rod pass line by a required level, and the other end is connected to the gas chamber for flow and heating, and the ejection hole at the tip is equal to or higher than the upper partition wall level. A plurality of distribution nozzles that stop at a slightly higher level are arranged such that the lower distribution nozzle is located in the space between the higher distribution nozzles, and the difference in the level of the ejection holes of the two distribution nozzles causes the particle size to drop. Body fixed layer It has a configuration which defines a shallow particle fluidized bed depths than the particle fixed bed.

The structure may be provided uniformly on the entire furnace body, but more preferably, the inside of the furnace is divided into a plurality of blocks by partition walls having a height from the furnace bottom to below the wire rod pass line, A main flow gas chamber and a flow and heating gas chamber are provided for each block, and two types of distribution nozzles are provided.

[Action]

Air is supplied to the main flow gas chamber, and flammable gas or a mixed gas of the flammable gas and air is supplied to the flow and heating gas chamber.

The air supplied to the main flow gas chamber passes through each distribution nozzle, and is ejected from an ejection hole which is opened at about the middle of the height of the granular layer, whereby the granular layer flows. In addition, the combustible gas supplied to the gas chamber for flowing and heating also passes through each of the other distribution nozzles and is ejected from the ejection hole into the granular layer. The ejection hole is opened at a lower level of the granular layer. Therefore, the granular layer in this region hardly moves due to the layer pressure applied from above,
It becomes a particle fixed layer.

The combustible gas ascends through the gaps between the particles and diffuses into the fluidized bed above the level of each distribution nozzle orifice, thereby further fluidizing the fluidized bed and mixing with air for combustion. Then, the particles in the fluidized bed are heated. The wire is heated by being sent through this fluidized bed.

The fixed particle layer has a greater layer thickness than the particle fluidized bed, and is cooled by gas ejected from the lower distribution nozzle and indirectly cooled by gas passing through the upper distribution nozzle. And the temperature gradient of the particle fixed layer is gentle. Therefore, the partition wall as a rectifier or a rectifier plate is not exposed to the fluidized bed temperature,
There is no problem even if the furnace temperature exceeds ℃.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 and 2 show an embodiment of a fluidized bed heat treatment furnace for wires according to the present invention. Reference numeral 1 denotes a furnace body, 1 is a furnace body made of a heat-resistant metal in a box shape, at least a side wall of which is covered with a refractory 1b, and a plurality of wires W for passing a plurality of wires W at both ends in the furnace length direction. An inlet 15 and an outlet 16 are provided, and the upper part of the furnace body is covered with an exhaust hood 17 having a chimney.

Reference numerals 2a, 2b, 2c, and 2d denote partition walls that are erected at regular intervals in the furnace. The partition walls 2a to 2d are respectively the bottom wall of the furnace body.
It has a height from 1a to a predetermined level (lower than the pass line connecting the inlet 10 and the outlet 11), and both side edges are hermetically connected to the width direction side wall of the furnace body by welding or the like. The area below the pass line is divided into five blocks A, B, C, D, and E.

Reference numeral 3 denotes a first (upper) partition wall stretched in the furnace below the pass line, and 4 denotes a second (lower) partition wall stretched between the first partition wall 3 and the furnace body bottom wall 1a. It is. The partition walls 3 and 4 are made of a heat-resistant metal, and the edges in the furnace width direction are connected to the furnace body side walls, respectively.
The furnace length direction edges of the partition walls 3 and 4 are air-tightly connected to the side walls of the furnace body, and the furnace length direction edges of the other partition walls are airtightly connected to the partition walls 2a to 2d. Gas chambers 5a to 5e for main flow and gas chamber 6a for flow and heating in the lower area respectively
To 6e are formed separately.

Reference numeral 7 denotes a number of distribution nozzles rising from the first partition wall 3 of each block. The distribution nozzles 7 are arranged at a predetermined interval from each other. Each distributing nozzle 7 is made of a heat-resistant material, and has a height (length) whose base end communicates with the main flow gas chambers 5a to 5e, and whose tip reaches a position below the pass line by a required level. A nozzle orifice 70 having a porous or lattice structure made of ceramic or heat-resistant metal is fixed at the tip.

Reference numeral 8 denotes a number of distribution nozzles rising from the second partition wall 4 of each block, which are arranged between the distribution nozzles 7. Each of the distribution nozzles 8 is also made of a heat-resistant material,
The proximal end communicates with the gas chambers for flow and heating 6a to 6e, while the distal end has the same height (length) as the first partition wall 3 or a level slightly higher than this. An orifice member 80 having a porous or lattice structure made of ceramic or heat-resistant metal is fixed to the nozzle.

Reference numeral 9 denotes a supply system connected to each of the main flow gas chambers 5a to 5e. The supply system 9 is connected to an air supply means 92 such as a blower or a fan. As shown, a control device 90 including a flow control valve is provided, whereby the main flow gas chamber of each of the blocks A to E is provided.
The amount of air supply to 5a to 5e can be arbitrarily adjusted. Preferably, each main flow gas chamber 5a to 5e has a second
As representatively shown in the figure, a measuring means 91 is provided to detect the amount of air or further the pressure and temperature, and to send a signal to the control device 90.

10 is a heating gas supply system connected to each of the flow and heating gas chambers 6a to 6e, and has a combustible gas line 102 and an air line 103, and these lines are provided with control valves 104 and 105, respectively. According to the required fluidized bed temperature, only the combustible gas or a mixture of the combustible gas and air can be selectively supplied. In particular, when heating above the red heat temperature, the gas density is about 1 /
Therefore, it is necessary to reduce the air supply amount by the control valve 105.

Further, a control device 100 including a flow control valve is provided downstream of the control valves 104, 104, whereby the gas supply amounts to the flow and heating gas chambers 6a to 6e of each of the blocks A to E are arbitrarily adjusted. It is possible to do. Also in this case, it is preferable that the control device 100 is operated by a signal from the measuring means 101 as shown in FIG.

Reference numeral 12 denotes a particle layer which is loaded at a height equal to or higher than the pass line with the first partition wall 3 of each of the blocks A to E as the bottom.
The particle layer 12 is made of solid particles such as alumina, zircon sand or silicon carbide. The particle layer 12 has a particle fixed layer 121 between the distribution nozzle 8 and the first partition wall 3 during operation, and a solid particle of the distribution nozzle 7. A particle fluidized bed 120 is formed between the nozzle member 70 and the layer surface.

Here, the depth h ₂ of the depth h ₁ and the particle fixed layer 121 of particles fluidized layer 120 is preferably set to h ₁ <h _2. This is because when h ₁ ≧ h ₂ , the thermal buffer effect of the particle fixing layer 121 cannot be expected, and the thermal strain of the first partition wall 3 increases. As a preferred example, when the furnace length is 1000 mm and the furnace width is 800 mm, h ₁ = 300 mm and h ₂ = 500 mm.

Note that the entirety of the particle layer 12 does not necessarily need to be the same. For example, the entire solid particles in the region to be the particle fixed layer 121 have a mass (if the same material is used) that in the region to be the particle fluidized bed 120. (A large particle diameter), or a multilayer structure in which the solid particles to be formed of the particle fixed layer 121 are substantially equal in surface to the particle fluidized bed, and the lower the layer, the larger the mass. With such a configuration, the gas from the distribution nozzle 8 rises more quickly, and a more firm particle fixing layer can be obtained.

In the other drawings, reference numeral 13 denotes an ignition pilot burner provided on the side wall of the furnace body, and reference numeral 14 denotes a measuring means for detecting the temperature of the particle layer. In addition, 15 is a maintenance plug for cleaning when particles fall from the distribution nozzle,
The main flow gas chambers 5a to 5e and the flow and heating gas chambers 6a to 6e are provided. Also, the maintenance plug is not shown,
It is also provided on the side of the granule storage zone for exchanging the granules.

In the case where the furnace is small, the partition walls 2a to 2d may not be provided, and it goes without saying that this is also included in the present invention. 3 to 5 show this embodiment. In this embodiment, a gas chamber 6 for flowing and heating is defined between the first partition wall 3 and the second partition wall 4, and the second
A main flowing gas chamber 5 is defined between the partition wall 4 and the bottom wall 1a.

Therefore, the distribution nozzle 7 whose base end communicates with the main flowing gas chamber 5 extends upward through the first partition wall 3, and the distribution nozzle 8 whose base end communicates with the flow and heating gas chamber 6 extends from the first partition wall 3. Stopped at a low height. The other points are the same as those of the above-described embodiment, and the description thereof is omitted.

[Operation of the embodiment]

The use and operation will be described with reference to FIGS. 1 and 2.

When the furnace of the present invention is used as a patenting furnace, a wire W, for example, a strand for stranding is drawn out in parallel from a swift (not shown) on the furnace body inlet side, and flows through a particle layer, that is, a particle fluidized bed 120 from an inlet 15. It is heated while passing through and guided to the outlet 16, then cooled by being passed through a cooling device of, for example, a fluidized powder type, and wound into a coil by a winder.

In the case of performing the above heating step, in the present invention, air is continuously fed into the main flow air chambers 5a to 5e by the supply systems 9, and the heating gas (combustible gas alone or a mixture thereof with air) is supplied by the supply system 10. Gas) is continuously fed into the gas chambers 6a to 6e for flowing and heating.

In this way, the air supplied to the main flow air chambers 5a to 5e rises through the respective distribution nozzles 7 and becomes the nozzle member 70 at the tip.
To the intermediate level of the particle layer 12 from the
The particle layer at a level above 70 is fluidized by aeration to form a particle fluidized bed 120. The heating gas supplied to the flow and heating air chambers 6a to 6e is supplied to the main flow air chamber.
It rises in each distribution nozzle 8 penetrating through 5a to 5e, and is ejected from the nozzle member 80 at the tip to the bottom level of the particle layer 12, but since this particle layer 12 is thick and pressed by gravity, the injection pressure It hardly moves and becomes the particle fixed layer 121.

Therefore, the heating gas is applied to the particle fixed layer as shown in Fig. 1a.
It rises through the particle gap of 121 and diffuses into the particle fluidized bed 120. Therefore, fluidization of the particle fluidized bed 120 is further promoted, and the particles are mixed with the air in the fluidized bed 120 with stirring. Then, when ignited by the pilot burner 13, the fuel burns vigorously, whereby the particle fluidized bed 120 is heated, and the wire W passing therethrough is heated.

In the present invention, instead of forming the entire particle layer on the first partition wall 3 into a fluidized bed, a difference is provided in the injection port level of the distribution nozzles 7 and 8 so that the thick particle fixed layer 121 is formed on the first partition wall 3. We are creating it. Moreover, the particle fixed layer 121 is directly cooled by the flow of the heating gas ejected from the distribution nozzle 8 and also indirectly cooled by the air passing through the distribution nozzle 7.

Therefore, the particle fixing layer 121 has a gentle temperature gradient as schematically shown in FIG. 1a, and the temperature of the first partition wall 3
Tb does not exceed a certain value, for example, fluidized bed temperature Tt10
Even at 00 ° C., the temperature of the first partition wall can be 200 ° C. or less. In addition, since the thermal buffer layer is composed of solid particles, it can absorb distortion due to heat, and there is no possibility of breakage.

Therefore, even if the fluidized bed temperature is set to 1100 ° C. or higher, the life of the first partition wall 3 can be significantly prolonged, and at the same time, the wire heating time is shortened by 40% or more compared to the conventional case where the maximum temperature is 700 ° C. It is possible to perform a very efficient heat treatment. In addition, since there is no clogging of the rectifying device due to oxidation or oxide as in the related art, maintenance is improved.

The nozzle member 70 of the distribution nozzle 7 has a high temperature, but if this material is made of ceramic or the like, there is no problem. The nozzle itself is cooled by the air passing therethrough, and the outer peripheral side is a particle fixed layer.
There is no danger of deformation or destruction because it is surrounded by 121.

In a specific implementation, the thickness of the particle fluidized bed 120 and the particle fixed layer 121 is set, and under these conditions, the gas flow rate in the particle fluidized bed is within a predetermined range (for example, 8.0 to 12 cm /
s), and set the main flow air pressure and heating gas pressure (for example, 3400 to 3600 mmH ₂ O) so that the injection speed from the distribution nozzle is faster than the gas combustion speed. The necessary air amount and heating gas amount may be controlled by the control devices 90 and 100 accordingly.

Further, a plurality of partition walls 2a to 2d are provided in the furnace and divided into a plurality of blocks A to E in the furnace length direction.
~ E, distributing nozzles 7,8 are arranged and control devices 90,10
In the case where the flow rate and the like are individually controlled at 0, arbitrary blocks A to
By selectively operating E, the heating conditions and fluidization conditions can be freely changed, so that a wide range of wire diameters and materials can be processed. Moreover, since the partition walls 2a to 2d partition from the middle of the fluidized bed to the lower part, the expansion of the fluidized bed can be stabilized, the fluidized bed can be formed in a stable shape, and high-quality heat treatment can be performed.

The present invention provides a fluidized bed that is stable from low to high temperatures, so it is suitable as a heating means for patenting. In addition, Japanese Patent Application Publication No. 500177/1985 and Japanese Patent Publication No. 1-15563
The present invention can be applied to a wide range of heat treatments such as quenching and transformation for the production of low-carbon duplex steel wires (including steel wires) indicated in No. 2, and annealing, quenching and tempering, and bluing.

〔The invention's effect〕

According to the present invention described above, in a furnace in which solid particles are accommodated, heated and heated by flowing a wire while passing through a wire, heat treatment is performed. The gas chambers 5a to 5e for main flow and the gas chambers 6a to 6e for flow and heating are formed and separated from each other, and the upper partition wall 3 is filled with granules.
The base end of one of the three partition walls 3 and 4 has a main flow gas chamber 5a.
5e, a plurality of distributing nozzles 7 each having a leading end orifice reaching a position below the wire rod pass line by a required level, and the other end having a base end leading to a flow / heating gas chamber 6a to 6e. And a plurality of distribution nozzles 8 stopping at a level equal to or slightly higher than the upper partition wall 3 such that the lower distribution nozzle 8 is located in the space between the higher distribution nozzles 7. The granules are divided into the particle fixed layer 121 and the particle fixed layer 1 by the level difference between the ejection holes of the two distribution nozzles 7 and 8.
Since it is defined in the particle fluidized bed 120 shallower than 21, the wire can be subjected to a wide range of heat treatment from a low temperature to a high temperature, and in particular, supplied to the air chambers 6a to 6e for flow and heating. The heating gas rises in each distribution nozzle 8 penetrating through the main flow air chambers 5a to 5e, and flows from the nozzle member 80 at the tip to the particle layer 12.
However, since the particle layer 12 is thick and pressed by gravity, it hardly moves due to the injection pressure, becomes the particle fixed layer 121, and provides a difference in the nozzle level of the distribution nozzles 7 and 8. As a result, a particle fixed layer 121 thicker than the particle fluidized bed 120 is created on the first partition wall 3, and the particle fixed layer 121 is directly cooled by the flow of the heating gas ejected from the distribution nozzle 8 and distributed. Nozzle 7
Since the heat resistance, which is indirectly cooled by air passing through the inside, can be improved, heat treatment in the temperature range of 1000 to 1100 ° C exceeding the red heat temperature range can be performed stably for a long time during connection, and it is always stable Since the shape of the fluidized bed can be obtained, high-quality heat treatment can be performed, and excellent effects such as easy maintenance can be obtained because clogging of the rectifying means does not occur.

Further, according to the fourth aspect of the present invention, since the inside of the furnace is divided into a plurality of blocks by the partition walls and the flow conditions and the heating conditions are set for each of these blocks so that they can be operated simultaneously, the processing of the wire W per unit time By selectively operating any of the blocks A to E according to the amount, heating conditions and fluidization conditions can be freely changed, and therefore, a wide range of wire diameters and materials can be processed. Moreover, since the partition walls 2a to 2d partition from the middle of the fluidized bed to the lower part, the fluidized bed can be formed into a fluidized bed shape in which expansion of the fluidized bed is stabilized, and an excellent effect that high-quality heat treatment is possible is obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing one embodiment of the present invention, FIG. 1a is an explanatory view showing a partially enlarged view of FIG. 1 together with a temperature gradient, and FIG. FIG. 3 is a longitudinal side view showing another embodiment of the present invention, FIG. 4 is a longitudinal front view thereof, FIG. 5 is a partial plan view thereof, and FIG. 6 (a). (E) is a sectional view of a conventional fluidized bed heating furnace. 1 ... furnace body, 2a-2d ... wall, 3 ... first partition wall, 4
...... Second partition wall, 5a-5e ... Main flow gas, 6a-6e ...
… Heating and flowing gas chamber, 7,8 …… Distribution nozzle, 9,10 ……
Supply system, 12 ... Particle layer, 90,100 ... Control device, 120 ...
Particle fixed bed, 121: Particle fluidized bed

Claims (5)

(57) [Claims] 1. A furnace in which solid particles are accommodated, and heat treatment is performed by passing the wire while heating and flowing the gas through a gas, wherein a main flow is provided at a lower portion of the furnace body 1 through two partition walls 3, 4. The gas chambers 5, 5a to 5e and the gas chambers 6, 6a to 6e for flowing and heating are defined and filled with the granular material on the upper partition wall 3, and one of the two partition walls 3, 4 has: Gas flow chamber for main flow at base end
A plurality of distributing nozzles 7 whose leading orifices reach the position below the wire pass line by a required level through 5,5a to 5e, and the other end has flow and heating gas chambers 6,6a to 6e at the base end. A plurality of distribution nozzles 8 whose discharge ports at the leading end stop at a level equal to or slightly higher than the upper partition wall 3 are provided in a space between the lower distribution nozzle 8 and the higher distribution nozzle 7. The particles are defined so as to be positioned, and the particles are defined as a particle fixed layer 121 and a particle fluidized bed 120 having a smaller depth than the particle fixed layer 121 due to the level difference between the ejection holes of the two distribution nozzles 7 and 8. A fluidized bed heat treatment furnace for wire rods. 2. The main flow gas chambers 5, 5a to 5e are in the upper position, and the flow and heating gas chambers 6, 6a to 6e are in the lower position.
The fluidized bed heat treatment furnace for wires according to claim 1, wherein the distribution nozzles (6, 6a to 6e) penetrate the upper partition wall (3). 3. The main flow gas chambers 5, 5a to 5e are lower, the flow and heating gas chambers 6, 6a to 6e are higher, and the main flow gas chambers 5, 5a
The fluidized bed heat treatment furnace for wires according to claim 1, wherein the distribution nozzles (7) to (5e) penetrate the upper partition wall (3). 4. A plurality of blocks A, B, C, D, and E are formed by partitions 2a to 2d having a height from the furnace bottom 1a to below the wire rod pass line.
Claims are provided in which the main flow gas chambers 5a to 5e and the flow and heating gas chambers 6a to 6e are provided for each block and two types of distribution nozzles 7, 8 are provided. 4. A fluidized bed heat treatment furnace for the wire rod according to any one of items 1 to 3. 5. The main flow gas chambers 5, 5a to 5e and the flow and heating gas chambers 6, 6a to 6e are connected to supply systems 9, 10 via respective control devices 90, 100, and the fluid supply conditions are individually set. Claims 1 to 4 that are controlled in a controlled manner
Item 10. A fluidized bed heat treatment furnace for wire rods according to any of the above items.