JP2003307301A - Radiant tube burner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiant tube burner for improving heat efficiency by improving exhaust heat recovering efficiency of combustion gas. <P>SOLUTION: This single end type radiant tube burner 1 is constituted by arranging a burner body 2 on one end, and blocking up the other end. The radiant tube burner 1 has a cylindrical heat exchange body 5 arranged between a partition wall 22 and an inner tube 4 so as to be connected in the shaft direction of an outer tube 3. A second exhaust passage 82 for communicating with a first exhaust passage 81 is formed between the heat exchange body 5 and the inner tube 4, and a third exhaust passage 83 for communicating with an exhaust port 24 is formed between the heat exchange body 5 and the partition wall 22. The heat exchange body 5 is provided with an exhaust communicating hole 51 for communicating the second exhaust passage 82 and the third exhaust passage 83. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a radiant tube burner for heating an atmospheric gas in a heat treatment furnace without directly contacting with a combustion gas.

[0002]

2. Description of the Related Art As shown in FIGS. 9 to 11, combustion gas 102 from a burner nozzle 920 is passed through a radiant tube 90.
Of the combustion gas 102 and the heat treatment furnace 6 through the inside of the furnace.
There is a radiant tube burner 9 that heats the inside of the heat treatment furnace 6 by the radiant heat from the surface of the radiant tube 90 without directly contacting the atmospheric gas 103 therein. As an example thereof, a radiant tube 9 having a double tube structure having an outer tube 3 and an inner tube 4
Burner body 9 having burner nozzle 920 at one end
There is a single end type radiant tube burner 9 configured by providing 2 and sealing the other end.

In the radiant tube burner 9, the combustion air 101 sucked from the intake port 923 is caused to flow in the first intake passage 971 formed between the housing 921 of the burner body 92 and the partition wall 922. Then, the combustion air 101 is supplied to the inner tube 9
4, the second intake passage 972 formed between the inside of the inner tube 94 and the burner nozzle 920 is caused to flow, and is burned together with the fuel injected from the burner nozzle 920.

Thereafter, the combustion gas 102 that has undergone this combustion
From the other end of the inner tube 94, a first exhaust passage 981 formed between the inner tube 94 and the outer tube 93, and a second exhaust passage 982 formed between the inner tube 94 and the partition wall 922. And is discharged from the exhaust port 924.

When the combustion gas 102 flows, the first exhaust passage 981 and the second exhaust passage 98
The combustion gas 102 flowing through the inner tube 9
By using 4 as a heat transfer surface and exchanging heat with the combustion air 101 flowing into the inner tube 94,
Exhaust heat from the combustion gas 102 is recovered.

[0006]

However, the combustion gas 1 flowing through the first exhaust passage 981 and the second exhaust passage 982
02 almost linearly flows to the exhaust port 924. Therefore, in the conventional single-ended radiant tube burner 9 described above, the combustion gas 10
The exhaust heat recovery efficiency of No. 2 is not so good, and the heat efficiency of the radiant tube burner 9 cannot be improved much after all. In addition, since the heat insulating material 95 for preventing the burner body 92 from reaching a high temperature is arranged on the side of the second exhaust passage 982 of the partition wall 922, it is difficult to further improve the thermal efficiency. ing.

The present invention has been made in view of the above conventional problems, and improves the exhaust heat recovery efficiency of combustion gas.
It is intended to provide a radiant tube burner capable of improving thermal efficiency.

[0008]

According to the present invention, there is provided a housing in which an intake port and an exhaust port are arranged in the outer peripheral direction, a partition wall arranged on the inner peripheral side of the housing, and a burner nozzle arranged on the inner peripheral side of the partition wall. A cylindrical burner body provided with an outer tube connected to the outer peripheral side of the burner nozzle in the axial direction of the burner body, and an inner tube disposed between the burner nozzle, the partition wall and the outer tube. The combustion air sucked from the intake port is caused to flow in an intake passage formed between the housing and the partition wall, is made to flow from one end of the inner tube, and is injected from the burner nozzle. And burn the combustion gas from the other end of the inner tube between the inner tube and the outer tube. In a radiant tube burner configured to flow the formed first exhaust passage and guide it to the exhaust port, a cylindrical heat exchange is performed between the partition wall and the inner tube so as to connect in the axial direction of the outer tube. A body is provided, and a second exhaust passage communicating with the first exhaust passage is provided between the heat exchange body and the inner tube.
An exhaust passage is formed, and a third exhaust passage communicating with the exhaust port is formed between the heat exchange body and the partition wall, and the heat exchange body is provided with the second exhaust passage and the exhaust passage. The radiant tube burner is provided with an exhaust communication hole communicating with the third exhaust passage (claim 1).

In the radiant tube burner of the present invention, a cylindrical heat exchange body is provided between the partition wall of the burner body and the inner tube to efficiently recover the exhaust heat from the combustion gas. . Exhaust heat recovery performed when the combustion gas flows through each exhaust passage will be described below. That is, the combustion gas burned from the burner nozzle flows through the first exhaust passage, the second exhaust passage, and the third exhaust passage, and is exhausted from the exhaust port to the outside of the radiant tube burner.

When the combustion gas flows in the first exhaust passage and the second exhaust passage, the combustion gas exchanges heat with the combustion air flowing in the inner tube with the inner tube serving as a heat transfer surface. The temperature of this combustion air can be raised. In this way, as the first stage exhaust heat recovery, the exhaust heat due to the combustion gas flowing through the first exhaust passage and the second exhaust passage can be recovered.

Then, the combustion gas from which the exhaust heat of the first stage has been recovered flows from the second exhaust passage to the third exhaust passage through the exhaust communication hole provided in the heat exchange body. When the combustion gas from which the exhaust heat of the first stage has been recovered flows in the third exhaust passage, the combustion gas exchanges heat with the combustion air flowing in the intake passage by using the partition wall as a heat transfer surface. The temperature of this combustion air can be raised. Thus, as the second stage exhaust heat recovery, the exhaust heat due to the combustion gas flowing through the third exhaust passage can be recovered.

As described above, according to the present invention, by providing the heat exchange body to form the second exhaust passage and the third exhaust passage, the combustion from the first exhaust passage to the exhaust port is performed. Gas can be made difficult to flow.
Then, the exhaust heat recovery efficiency of the combustion gas can be improved by performing the two stages of exhaust heat recovery with the residence time of the combustion gas in the radiant tube burner being lengthened. Therefore, the thermal efficiency of the radiant tube burner can be improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The preferred embodiments of the present invention described above will be described. The radiant tube burner of the present invention can be fixed to the furnace wall of a heat treatment furnace and used to heat the atmospheric gas in the heat treatment furnace without contacting with the combustion gas. Then, the radiant tube burner is designed so that the atmosphere gas in the heat treatment furnace is 500 to 11
It is preferably used when heating to a temperature of 00 ° C.
In this case, the high thermal efficiency can be realized without heating the burner body so much. When the atmospheric gas in the heat treatment furnace is heated to a temperature higher than 1100 ° C., it is necessary to cool the burner body by providing a cooling means such as a heat insulating material in the burner body.

The exhaust communication hole in the heat exchange body is
It is preferable that the burner body is provided on the opposite side to the exhaust port in the outer peripheral direction (claim 2). In this case, the combustion gas flowing in the second exhaust passage and the third exhaust passage easily flows into the exhaust port, and exhaust heat recovery in the first and second stages is not sufficiently performed. As it is, it is possible to easily prevent exhaust from the exhaust port.

Further, the exhaust communication hole in the heat exchange body is provided near one end of the heat exchange body, and the exhaust port in the burner body is provided near the other end of the heat exchange body. It is preferable to provide (claim 3). Also in this case, the combustion gas flowing in the second exhaust passage and the third exhaust passage easily flows into the exhaust port, and exhaust heat recovery in the first and second stages is not sufficiently performed. As it is, it is possible to easily prevent exhaust from the exhaust port.

Further, it is preferable that a plurality of exhaust communication holes are provided in the heat exchange body (claim 4). In this case, the second exhaust passage and the third exhaust passage can be communicated with each other through the plurality of exhaust communication holes.

Further, it is preferable that a baffle plate for hindering the flow of the combustion gas into the exhaust communication hole is provided on the upstream side of the flow of the combustion gas in the heat exchange body with respect to the exhaust communication hole. ). In this case, the combustion gas can be made difficult to flow from the second exhaust passage to the third exhaust passage through the exhaust communication hole. for that reason,
With the residence time of the combustion gas in the radiant tube burner being made longer, the two stages of exhaust heat recovery can be performed.

Further, it is preferable that the heat exchange body is detachably attached to the burner body (claim 6). In this case, by exchanging the heat exchange body, the heat exchange body can be easily replaced or maintained.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) As shown in FIGS. 1 to 3, a radiant tube burner 1 of the present embodiment is provided with a burner body 2 at one end of a radiant tube 10 having a double tube structure having an outer tube 3 and an inner tube 4. A single-ended radiant tube burner 1 having the other end closed. In this example, a cylindrical heat exchange body 5 is provided between the burner body 2 and the inner tube 4 to efficiently recover the exhaust heat of the combustion gas 102 burned by the burner nozzle 20.

That is, the radiant tube burner 1 has a housing 2 in which an intake port 23 for combustion air 101 and an exhaust port 24 for the combustion gas 102 are arranged in the outer peripheral direction.
1 and a partition wall 22 arranged on the inner peripheral side of the housing 21
And the burner nozzle 20 arranged on the inner peripheral side of the partition wall 22.
It has a cylindrical burner body 2 provided with. Further, the radiant tube is arranged on the outer peripheral side of the burner nozzle 20 and is arranged between the outer tube 3 connected in the axial direction of the burner body 2 and the burner nozzle 20, the partition wall 22 and the outer tube 3. The inner tube 4 is provided.

An intake passage 71 for opening the intake port 23 is formed between the housing 21 and the partition wall 22, and the combustion gas is provided between the inner tube 4 and the outer tube 3. A first exhaust passage 81 is formed to allow 102 to flow. Further, the radiant tube burner 1 has a tubular heat exchange body 5 arranged between the partition wall 22 and the inner tube 4 so as to be connected in the axial direction of the outer tube 3.

Due to the disposition of the heat exchange body 5, a second exhaust passage 82 communicating with the first exhaust passage 81 is provided between the heat exchange body 5 and the inner tube 4.
Are formed, the heat exchange body 5 and the partition wall 22 are formed.
And the third exhaust passage 8 communicating with the exhaust port 24.
3 is formed. Further, the heat exchange body 5 is provided with an exhaust communication hole 51 that communicates the second exhaust passage 82 and the third exhaust passage 83.

In the radiant tube burner 1, the combustion air 101 sucked from the intake port 23 is
The intake passage 71 is made to flow and is made to flow from one end of the inner tube 4, and is burned together with the fuel injected from the burner nozzle 20. Then, the combustion gas 102 that has undergone this combustion is transferred from the other end of the inner tube 4 to the first exhaust passage 81 and the second exhaust passage 82.
Then, it is flowed to the third exhaust passage 83 and discharged from the exhaust port 24 to the outside of the radiant tube burner 1.

This will be described in detail below. In this example, as shown in FIGS. 1 to 3, the radiant tube burner 1 is used to heat the atmosphere gas 103 in the heat treatment furnace 6, and the atmosphere gas 103 is brought into direct contact with the combustion gas 102. Heat without. Also,
In this example, the radiant tube burner 1 is used at a temperature of the atmosphere gas 103 in the heat treatment furnace 6 of 500 to 110.
Used when heating to 0 ° C. The radiant tube 1 of this example is a straight type in which the outer tube 3 and the inner tube 4 have a linear shape.

The radiant tube burner 1 is fixed to the furnace wall 61 of the heat treatment furnace 6, and the burner nozzle 2
The combustion gas 102, which has been burnt at 0, exchanges heat with the atmosphere gas 103 in the heat treatment furnace 6 using the outer tube 3 as a heat transfer surface.
Heat 3. Further, the outer tube 3 is fixed to the outer wall surface 611 of the furnace wall 61 by a fixing portion 31, and the burner body 2 has the heat exchange body 5 detachably disposed therein to fix it. It is attached to the part 31.

The intake port 23 is arranged on the furnace wall side of the burner body 2, and the exhaust port 24 is provided.
Is disposed on the opposite side of the burner body 2 from the furnace wall. In this example, the side closer to the furnace wall 61 is called the furnace wall side, and the side farther from the furnace wall 61 is called the furnace wall opposite side. The partition wall 22 of the burner body 2 is provided from the end of the housing 21 on the furnace wall side,
The partition wall 22 opens the intake passage 71 on the opposite side of the furnace wall.

The inner tube 4 has its end on the furnace wall side attached to the end of the partition wall 22 on the opposite side of the furnace wall, and the burner nozzle 20 is on the opposite side of the burner body 2 to the furnace wall. It is fixed to the end of the inner tube 4 and is disposed inside the inner tube 4. A second intake passage 72 is formed between the inside of the inner tube 4 and the burner nozzle 20. In this example, the intake passage 71 is used as a first intake passage 71, and the first intake passage 71 and the second intake passage 72 are communicated with each other at an end portion of the burner body 2 opposite to the furnace wall.

Further, the exhaust communication hole 51 in the heat exchange body 5 is provided at a position farthest from the exhaust port 24 in the burner body 2 in the outer peripheral direction. The exhaust communication hole 51 is provided near the furnace wall side end of the heat exchange body 5. A plurality of the exhaust communication holes 51 may be provided on the opposite side of the exhaust port 24 in the burner body 2 in the outer peripheral direction (see FIGS. 6 and 7).

Below, the radiant tube burner 1 is used.
And the combustion gas 102 is heated by each exhaust passage 8
Exhaust heat recovery performed when flowing through 1, 82, 83 will be described. First, as shown in FIG.
Combustion air 101 is sucked in from 3 and the combustion air 10
1 is made to flow through the first intake passage 71 and the second intake passage 72. Then, in the inner tube 4,
The combustion air 101 and the fuel injected from the burner nozzle 20 are mixed and burned.

Then, the combustion gas 102 that has undergone this combustion
Flows in the inner tube 4 toward the furnace wall side, contacts the tip portion 32 of the outer tube 3, and then flows into the first exhaust passage 81. The combustion gas 102 exchanges heat with the atmosphere gas 103 in the heat treatment furnace 6 with the outer tube 3 as a heat transfer surface, and heats the atmosphere gas 103.

Next, the combustion gas 102 is mixed with the first combustion gas.
It flows from the exhaust passage 81 to the second exhaust passage 82.
At this time, the first exhaust passage 81 and the second exhaust passage 82 are
The combustion gas 102 flowing through the inner tube 4 exchanges heat with the combustion air 101 flowing through the second intake passage 72 in the inner tube 4 with the inner tube 4 as a heat transfer surface, and the temperature of the combustion air 101 rises. (See FIG. 2 and FIG. 3). Thus, as the first stage exhaust heat recovery, the first exhaust passage 81 and the second exhaust passage 82 are provided.
Exhaust heat due to the combustion gas 102 flowing through can be recovered.

Next, the combustion gas 102 from which the exhaust heat of the first stage has been recovered is transferred from the second exhaust passage 82 to the third exhaust passage 83 through the exhaust communication hole 51 provided in the heat exchange body 5. And flow. When the combustion gas 102 from which the exhaust heat of the first stage has been recovered flows through the third exhaust passage 83, the combustion gas 102 uses the partition wall 22 of the burner body 2 as a heat transfer surface and the intake passage. By exchanging heat with the combustion air 101 flowing through 71, the temperature of the combustion air 101 can be raised (see FIGS. 2 and 3). In this way, as the second stage exhaust heat recovery, the exhaust heat due to the combustion gas 102 flowing through the third exhaust passage 83 can be recovered. Then, after that, the combustion gas 102 that has recovered the exhaust heat of the second stage is exhausted to the outside of the radiant tube burner 1 through the exhaust port 24.

As described above, in this embodiment, by providing the heat exchange body 5 and forming the second exhaust passage 82 and the third exhaust passage 83, the first exhaust passage 81 is formed.
Therefore, it is possible to make it difficult for the combustion gas 102 to flow toward the exhaust port 24. Then, the exhaust heat recovery efficiency of the combustion gas 102 is improved by performing the two-stage exhaust heat recovery in a state where the residence time of the combustion gas 102 in the radiant tube burner 1 is lengthened, and the radiant tube The thermal efficiency in the burner 1 can be improved.

(Second Embodiment) In this embodiment, as shown in FIGS. 4 and 5, in the radiant tube burner 1 of the first embodiment, the flow of the combustion gas 102 from the exhaust communication hole 51 in the heat exchange body 5 is increased. Of the exhaust communication hole 51 on the upstream side, that is, on the furnace wall side of the exhaust communication hole 51.
This is an example in which a baffle plate 52 that prevents the flow of the combustion gas 102 to the inside is provided. In this example, the baffle plate 52 is provided between the outer tube 3 and the inner tube 4, and the first exhaust passage 81 and the second exhaust passage 82 have an opening 521 provided in the baffle plate 52. Are communicated via. Others are the same as those in the first embodiment.

In this embodiment, the combustion gas 102 flowing in the first exhaust passage 81 is obstructed by the baffle plate 52, and the second combustion gas 102 flows only through the opening 521.
It flows to the exhaust passage 82. Therefore, the combustion gas 102 flowing through the first exhaust passage 81 does not flow much into the second exhaust passage 82, and the third exhaust passage 83 does not flow.
It can be prevented from flowing into. Therefore, the combustion gas 10 in the radiant tube burner 1 is
The two stages of exhaust heat recovery can be performed with the residence time of No. 2 further increased, and the thermal efficiency of the radiant tube burner 1 can be further improved. In addition, it is possible to obtain the same effect as that of the first embodiment.

As shown in FIGS. 6 and 7, the exhaust communication hole 51 is formed in the exhaust port 24 of the burner body 2.
Alternatively, a plurality may be provided on the opposite side in the outer peripheral direction.
In this case, the second exhaust passage 82 and the third exhaust passage 83 can be communicated with each other through the plurality of exhaust communication holes 51, and the same effect as this example can be obtained.

Example 3 In this example, in order to confirm the excellent effect of the radiant tube burner 1 (invention product, see FIGS. 1 to 3) having the heat exchange body 5,
The thermal efficiency (%) of the radiant tube burner 1 was measured. For comparison, the same measurement was performed for the conventional radiant tube burner 9 (comparative product, see FIGS. 9 to 11) that does not have the heat exchange body 5.

The results of the above measurements are shown in FIG. In the present example, the thermal efficiency H is set such that the temperature of the atmosphere gas 103 in the heat treatment furnace 6 (temperature in the furnace) is 500 to 10
When the temperature is maintained at 00 (° C.), a difference obtained by subtracting the exhaust heat amount Q2 of the combustion gas 102 discharged from the exhaust port 24 from the combustion heat amount Q1 consumed for combustion of the burner nozzle 20 is set as the combustion heat amount Q1. Divide, 100 (%) to this
(H = (Q1−Q2) / Q1 × 100)
(%)).

As shown in the figure, the thermal efficiency of the invention product was 78 to 95 (%), whereas that of the comparative product was 70 to 80 (%). That is, it was found that the thermal efficiency of the above-mentioned invention product is higher than that of the above-mentioned comparative product regardless of whether the furnace temperature is maintained at any temperature between 500 and 1000 (° C). Therefore, it can be seen that the radiant tube burner 1 having the heat exchange body 5 can realize high thermal efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view showing a radiant tube burner according to a first embodiment.

FIG. 2 is a diagram showing a radiant tube burner according to the first embodiment and is a cross-sectional view taken along the line AA in FIG.

FIG. 3 is a view showing a radiant tube burner according to the first embodiment, and is a cross-sectional view taken along the line BB in FIG.

FIG. 4 is an explanatory sectional view showing a radiant tube burner in the second embodiment.

5 is a view showing a radiant tube burner according to the second embodiment and is an explanatory cross-sectional view taken along the line AA in FIG.

FIG. 6 is a view showing a radiant tube burner using a heat exchange body having a plurality of exhaust communication holes according to the second embodiment, and is a cross-sectional explanatory view corresponding to the line AA of FIG. 4;

FIG. 7 is a perspective view showing a heat exchange body having a plurality of exhaust communication holes according to the second embodiment.

FIG. 8 is a graph showing the relationship between furnace temperature (° C.) and thermal efficiency (%) in Example 3.

FIG. 9 is a cross-sectional explanatory view showing a radiant tube burner in a conventional example.

10 is a view showing a radiant tube burner in a conventional example, which is a cross-sectional view taken along the line AA in FIG.

FIG. 11 is a view showing a radiant tube burner in a conventional example, and a cross-sectional view taken along the line BB in FIG.

[Explanation of symbols]

1. ． ． Radiant tube burner, 101. ． ． Combustion air, 102. ． ． Combustion gas, 103. ． ． Atmosphere gas, 2. ． ． Burner body, 20. ． ． Burner nozzle, 21. ． ． housing, 22. ． ． Partition wall, 23. ． ． Intake port, 24. ． ． exhaust port, 3. ． ． Outer tube, 4. ． ． Inner tube, 5. ． ． Heat exchange body, 51. ． ． Exhaust communication hole, 52. ． ． Baffle, 521. ． ． Aperture, 6. ． ． Heat treatment furnace, 71. ． ． First intake passage (intake passage), 72. ． ． The second intake passage, 81. ． ． First exhaust passage, 82. ． ． Second exhaust passage, 83. ． ． Third exhaust passage,

Continued front page    (72) Inventor Mitsuo Tomatsu             Aichi Prefecture Moriyama-ku Nagoya-shi Oishi Nakashidanji Oto             Exit 2720 Address 1 Inside Yokoi Machine Works Co., Ltd. F-term (reference) 3K017 BA01 BB04 BB07 BE05 BE08                       BE11                 3K091 AA20 BB08 BB26 CC06 CC22                       EA16 EA22

Claims (6)

[Claims] 1. A tubular shape comprising a housing having an intake port and an exhaust port arranged in an outer peripheral direction, a partition wall disposed on an inner peripheral side of the housing, and a burner nozzle disposed on an inner peripheral side of the partition wall. Of the burner body, an outer tube disposed on the outer peripheral side of the burner nozzle and connected in the axial direction of the burner body, and an inner tube disposed between the burner nozzle, the partition wall, and the outer tube. , The combustion air sucked from the intake port is caused to flow in an intake passage formed between the housing and the partition wall, flows from one end of the inner tube, and is burned with the fuel injected from the burner nozzle. A first exhaust gas formed between the inner tube and the outer tube from the other end of the inner tube through the combustion gas after the combustion. In the radiant tube burner configured to flow the air passage and guide it to the exhaust port, so as to connect in the axial direction of the outer tube,
A tubular heat exchange body is disposed between the partition wall and the inner tube, and a second exhaust passage communicating with the first exhaust passage is formed between the heat exchange body and the inner tube. A third exhaust passage communicating with the exhaust port is formed between the heat exchange body and the partition wall, and the heat exchange body has the second exhaust passage and the third exhaust passage. A radiant tube burner that has an exhaust communication hole that communicates with it. 2. The radiant tube burner according to claim 1, wherein the exhaust communication hole in the heat exchange body is provided on the opposite side of the exhaust port in the burner body in the outer peripheral direction. 3. The exhaust communication hole in the heat exchange body according to claim 1 or 2, wherein the exhaust communication hole is provided in the vicinity of one end of the heat exchange body, and the exhaust port in the burner body is provided in the heat exchange body. A radiant tube burner characterized by being provided in the vicinity of the other end. 4. The method according to claim 1, wherein
A radiant tube burner characterized in that a plurality of exhaust communication holes are provided in the heat exchange body. 5. The method according to any one of claims 1 to 4,
A radiant tube burner, characterized in that a baffle plate that prevents the flow of the combustion gas into the exhaust communication hole is provided on the upstream side of the flow of the combustion gas in the heat exchange body with respect to the exhaust communication hole. 6. The method according to any one of claims 1 to 5,
The radiant tube burner, wherein the heat exchange body is detachably attached to the burner body.