JP4877680B2 - Wire heating furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wire heating furnace for heating a wire such as a tungsten wire to a high temperature.
[0002]
[Prior art]
For example, as a wire heating furnace for heating a wire such as tungsten conveyed on a production line to a high temperature in a short time, a flame is placed on one end of a cylindrical combustion chamber configured to allow the wire to pass on the central axis. Conventionally, a configuration in which a burner is installed so as to swirl along the inner wall of the combustion chamber and the wire is heated by a swirling flame and radiant heat from the combustion chamber wall has been proposed.
[0003]
4 and 5 are examples thereof, and those shown in FIGS. 6 and 7 are other examples. 5 is a cross-sectional view taken along the line CC 'in FIG. 4, and FIG. 7 is a cross-sectional view taken along the line DD' in FIG.
In these figures, symbol a is a cylindrical combustion chamber, b is a burner installed on one end side of the cylindrical combustion chamber a, c is a wire, d is an exhaust cylinder, e is a waste heat recovery device, and burner b is air. The premixing burner is configured such that the air supplied from the inlet f and the fuel gas supplied from the fuel gas inlet g are mixed in advance, and the air-fuel mixture is ejected from the nozzle h, and the air is mixed with the fuel gas. In addition, the waste heat recovery device e is preheated by exchanging heat with the exhaust gas to increase the flame temperature and improve the efficiency.
[0004]
4 and 5, the nozzle h of the burner a is configured to form a swirling flow by injecting an air-fuel mixture at an angle in the axial direction of the cylindrical combustion chamber a. For example, it is described in Japanese Utility Model Publication No. 56-32877.
[0005]
6 and 7, the nozzle h of the burner a is configured to inject a mixture from a direction perpendicular to the axial direction of the cylindrical combustion chamber a to form a swirling flow. For example, it is described in Japanese Utility Model Publication No. 57-32347.
[0006]
[Problems to be solved by the invention]
In the conventional wire heating furnace described above, the burner installed at one end of the cylindrical combustion chamber is a premix burner that burns the air-fuel mixture. There is a limit to temperature.
For this reason, flame temperature and furnace temperature cannot be raised above a certain temperature, and it takes time to raise the temperature of the wire.
Therefore, the conveyance speed of the wire cannot be increased, and the required furnace length becomes long, so that there is a problem that installation becomes difficult in a production line with a limited space.
The present invention aims to solve such problems.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, in the present invention, a partitioning cylinder is installed coaxially with a space inside the cylindrical combustion chamber configured to allow a wire to pass through the central axis, Comprises a space on one end side of the partitioning cylinder, a burner is arranged around it, an exhaust pipe is formed at an appropriate location, and the burner supplies fuel gas and oxidant toward the outer periphery of the wire. A wire heating furnace is proposed which is configured as a premixed burner that jets to form a swirling flow, and the partitioning cylinder is provided with a communication hole at a position away from the burner.
[0008]
In the present invention, it is proposed that the burner is configured to eject the fuel gas and the oxidant in a direction perpendicular to the wire, or to eject the fuel gas and the oxidant in a direction other than the direction perpendicular to the wire.
[0009]
According to the present invention, in the above configuration, the burner is proposed to be configured by an injection nozzle in which a fuel gas injection unit is arranged at the center and an air injection unit is arranged around the fuel gas injection unit.
[0010]
And in this invention, it proposes that a space part is made into a truncated cone shape in said structure.
[0011]
Furthermore, in the present invention, the present invention proposes that the partitioning cylinder is made of a material having heat resistance and heat transfer properties such as ceramics.
[0012]
Furthermore, in the present invention, in the above configuration, it is proposed that the exhaust pipe is configured with a waste heat recovery unit for exchanging heat with the oxidant supplied to the burner.
[0013]
In the present invention, air, oxygen-enriched air, or oxygen can be used as the oxidizing agent.
[0014]
According to the present invention, in the space on the one end side of the partitioning cylindrical body, the fuel gas and the oxidant are ejected from the burner toward the outer peripheral direction of the wire, so that the flame slightly touches the outer periphery of the wire, It turns at the inner peripheral wall of the space, and then moves while turning in the direction of the other end of the partitioning cylinder.
[0015]
Therefore, the wire is heated by the convection heat of the flame, the flame and the radiant heat from the inner wall surface of the partitioning cylinder, and the predetermined heating is performed in a short time while preventing local heating.
[0016]
The flame that has moved from one end side to the other end side of the partitioning cylinder passes through a communication hole provided at a position away from the burner and reaches a space between the partitioning cylinder and the outside of the partitioning cylinder. After the wall surface is heated, it is exhausted through an exhaust pipe.
[0017]
Since flames are formed on the inside and outside of the partitioning cylinder in this way, the partitioning cylinder is heated to a higher temperature, and hence the amount of radiant heat transfer to the wire is increased, and the wire is heated to a high temperature in a short time. Can be heated.
[0018]
Since the wire can be heated to a high temperature in a short time, the furnace length can be shortened and the conveying speed of the wire can be increased.
[0019]
In the present invention, the burner is not a premix burner as in the prior art, but is a premix burner, so there is no risk of backfire even if the oxidant is preheated to a higher temperature.
[0020]
For this reason, in the case where the oxidant is preheated in the waste heat recovery unit provided in the exhaust pipe, the preheating temperature can be further increased, so that the temperature in the furnace can be increased also in this respect.
[0021]
If the space portion formed on one end side of the partitioning cylinder has a truncated cone shape, the end portion can be configured as a guide means for the wire, allowing the wire to pass through without shifting from the central axis, and It becomes easy for the swirling flow to move toward the partitioning cylinder.
[0022]
As an oxidant, not only air but also oxygen-enriched air or oxygen can be used to further increase the furnace temperature, further shortening the heating time and making the furnace compact. Is possible.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to FIGS.
1 is a longitudinal sectional view showing a wire rod heating furnace to which the present invention is applied, FIG. 2 is a sectional view taken along line AA 'in FIG. 1, and FIG. 3 is a sectional view taken along line BB' in FIG.
Reference numeral 1 denotes a cylindrical combustion chamber configured such that the wire rod 3 can pass over the central shaft 2, and the cylindrical combustion chamber 1 is configured using a refractory heat insulating material. Inside the cylindrical combustion chamber 1, a partitioning cylinder 4 is installed coaxially with an interval, and the inside of the cylindrical combustion chamber 1 is divided into an inner layer i and an outer layer o.
[0024]
In the cylindrical combustion chamber 1, a space portion forming member 6 that forms a truncated cone-shaped space portion 5 is installed on one end side of the partitioning cylinder 4, that is, on the right end side in the drawing. The member 6 is comprised with the fireproof heat insulating material. A guide hole 7 is formed in the narrow end portion of the space forming member 6 to prevent the wire 3 from shifting and to maintain it on the central axis.
[0025]
A plurality of, in this case, four air nozzles 8 are provided in the space portion forming member 6 in the radial direction, and a fuel gas nozzle 9 is provided on the inner coaxial axis thereof to constitute a premixing burner 10. An air chamber 11 is provided outside the space forming member 6, and a fuel gas chamber 12 is provided outside the air chamber 11.
[0026]
The four burners 10 are arranged so that the air from the air nozzle 8 and the fuel gas from the fuel gas nozzle 9 are in the direction perpendicular to the wire 3 as shown in FIG. 1 and the outer periphery of the wire 3 as shown by the broken line in FIG. It is configured to eject in the direction.
[0027]
In the cylindrical combustion chamber 1, an exhaust pipe 13 is provided at a position slightly closer to the burner 10. A waste heat recovery unit 14 is provided on the outer periphery of the exhaust pipe 13, and the waste heat recovery unit 14 is provided from the air inlet 15. A preheated air path 17 that reaches the preheated air inlet 16 of the air chamber 11 is formed.
[0028]
A plurality of communication holes 18 for communicating the inner layer i and the outer layer o are provided on the other end side of the partitioning cylinder 4.
[0029]
In the above configuration, the preheated air that reaches the waste heat recovery device 14 from the air inlet 15, where it is preheated by exchanging heat with the exhaust gas, and then reaches the air chamber 11 through the preheated air path 17 passes from the air nozzle 8 to the space portion. At the same time, the fuel gas supplied from the fuel gas inlet 19 to the fuel gas chamber 12 is jetted from the fuel gas nozzle 9 on the coaxial inner side of the air nozzle 8 to the inside of the space portion 5, and an appropriate ignition source Is ignited to form a flame.
[0030]
At this time, since the fuel gas and air are ejected from the burner 10 toward the outer periphery of the wire 3, the flame slightly touches the outer periphery of the wire 3, and then swirls on the inner peripheral wall 20 of the space portion 5. It moves while turning in the other end side direction in the partition cylinder 4, that is, in the inner layer i.
[0031]
Therefore, the wire 3 is heated by the convection heat of the flame and the radiant heat from the flame and the inner wall surface of the partitioning cylinder 4, and the predetermined heating is performed in a short time while preventing local heating.
[0032]
The flame that has moved the inner layer i from one end side to the other end side of the partitioning cylinder 4 passes through the communication hole 18 provided at a position away from the burner 10, that is, the space between the cylindrical combustion chamber 1, that is, After reaching the outer layer o, the outer wall surface of the partitioning cylinder 4 is heated, and then exhausted through the exhaust cylinder 13.
[0033]
As described above, the partitioning cylinder 4 is heated with a flame formed inside and outside thereof, and thus is heated to a higher temperature than that in which the flame is formed only on the inside. Accordingly, the amount of radiant heat transferred from the inner wall surface of the partitioning cylinder 4 to the wire 3 is increased, and the wire 3 can be heated to a high temperature in a short time.
[0034]
Since the wire 3 can be heated to a high temperature in a short time in this way, the length of the cylindrical combustion chamber 1, and hence the length of the wire heating furnace, can be configured to be short and compact. The entire line can be made compact and the conveying speed of the wire 3 can be increased.
[0035]
In the above operation, the burner 10 is not a premix burner as in the prior art, but is a premix burner, so there is no risk of backfire even if the waste heat recovery unit 14 preheats the air to a higher temperature. Thus, since the preheating temperature of the air can be further increased, the furnace temperature, particularly the temperature of the inner layer i can be further increased and the fuel consumption can be reduced.
[0036]
In this embodiment, the space 5 formed on one end side of the partitioning cylinder 4 has a truncated cone shape, so that the guide hole 7 of the wire 3 is provided at the end, and the wire 3 is displaced from the central axis. And the flame swirl flow easily moves in the direction of the partitioning cylinder 4.
[0037]
In the above embodiment, air is used as the oxidant, but oxygen-enriched air or oxygen can also be used as the oxidant. In these cases, the furnace temperature is further increased. Therefore, the heating time of the wire 3 can be further shortened and the wire heating furnace can be made compact.
[0038]
As described above, in this embodiment, the four burners 10 are configured to eject air and fuel gas in a direction perpendicular to the wire 3 as shown in FIG. As described above, the burner 10 can be appropriately inclined with respect to the wire 3 at an angle other than a right angle.
[0039]
【Effect of the invention】
Since the present invention is as described above, the following effects are obtained.
a. The wire is heated by the convection heat of the flame, the radiant heat of the flame, and the radiant heat from the inner wall surface of the partitioning cylinder heated to the inside and outside by the flame, so that local heating is prevented for a short time. It can be heated to a high temperature, the furnace length can be shortened to make it compact, and the conveying speed of the wire can be increased.
b. Since the burner is not a premix burner as in the past, but a premix burner, there is no danger of backfire even if the oxidant is preheated to a higher temperature, and the oxidizer is used in the waste heat recovery unit provided in the exhaust stack. When preheating is performed, the preheating temperature can be increased, so that the temperature in the furnace can be increased also in this respect.
c. If the space portion formed on one end side of the partitioning cylinder has a truncated cone shape, the end portion can be configured as a guide means for the wire, allowing the wire to pass through without shifting from the central axis, and It becomes easy for the swirling flow to move toward the partitioning cylinder.
d. As an oxidant, not only air but also oxygen-enriched air or oxygen can be used to further increase the furnace temperature, further shortening the heating time and making the furnace compact. Is possible.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a wire heating furnace to which the present invention is applied.
FIG. 2 is a cross-sectional view taken along line AA ′ of FIG.
FIG. 3 is a cross-sectional view taken along the line BB ′ of FIG.
FIG. 4 is a longitudinal sectional view showing an example of a conventional wire heating furnace.
FIG. 5 is a cross-sectional view taken along the line CC ′ of FIG.
FIG. 6 is a longitudinal sectional view showing another example of a conventional wire heating furnace.
7 is a cross-sectional view taken along the line DD ′ of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylindrical combustion chamber 2 Center axis | shaft 3 Wire rod 4 Partition cylinder 5 Space part 6 Space part formation member 7 Guide hole 8 Air nozzle 9 Fuel gas nozzle 10 Burner 11 Air chamber 12 Fuel gas chamber 13 Exhaust cylinder 14 Waste heat recovery device 15 Air inlet 16 Preheated air inlet 17 Preheated air path 18 Communication hole 19 Fuel gas inlet 20 Inner peripheral wall

Claims (7)

A partitioning cylinder is installed coaxially with an interval inside the cylindrical combustion chamber configured to allow the wire to pass through the central axis, and the cylindrical combustion chamber is provided with one end side of the partitioning cylinder. A space forming member that forms a frustoconical space whose diameter increases toward the partitioning cylinder is installed, a guide hole for the wire is formed at the narrow end of the space forming member, and a burner is formed around the space. And an exhaust nozzle is formed at an appropriate position of the cylindrical combustion chamber, and a burner is provided in the radial direction of the space portion forming member and is opened to the inner peripheral wall of the space portion forming member , and the air It is composed of a fuel nozzle provided coaxially on the inner side of the nozzle, and fuel gas and oxidant are ejected in the direction of the inner peripheral wall of the space forming member and toward the outer peripheral direction of the wire, and swirled on the inner peripheral wall It is configured as a premixed burner that forms a flow The cylinder for Ri, wire heating furnace, characterized in that a communication hole at a position away from the burner.   The wire heating furnace according to claim 1, wherein the burner is configured to eject the fuel gas and the oxidant in a direction perpendicular to the wire.   The wire heating furnace according to claim 1, wherein the burner is configured to eject the fuel gas and the oxidant in a direction other than a right angle to the wire.   The wire rod heating furnace according to claim 1, wherein the partitioning cylindrical body is made of a material having heat resistance and heat transfer properties.   The wire rod heating furnace according to claim 1, wherein the exhaust pipe is configured with a waste heat recovery unit for exchanging heat with an oxidant supplied to the burner.   The wire heating furnace according to any one of claims 1 to 5, wherein the oxidizing agent is air.   The wire heating furnace according to any one of claims 1 to 5, wherein the oxidizing agent is oxygen-enriched air or oxygen.

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