JP2001012708A - Combustion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion apparatus for restricting an increase in production of NOx. SOLUTION: In a combustion apparatus including a combustion box 2 communicating with a flame hole portion 5 of a burner and forming a combustion chamber 22, there are provided partition plates 31, 32, 33 for dividing the inside of the combustion box into a plurality of combustion chambers 23, 24, 25. Secondary combustion air taken into the combustion chambers 23, 24, 25 is incorporated from an upper portion of the combustion chambers 23, 24, 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to city gas and LPG.
The present invention relates to a combustion device mainly used for a gas burner such as a gas.

[0002]

2. Description of the Related Art Generally, in a combustion apparatus having a combustion chamber connected to a flame hole of a burner, secondary combustion air is supplied to a flame formed in the combustion chamber to complete combustion.

FIG. 5 is a side sectional view showing a conventional burner main body 1 and a combustion box 2 forming a combustion chamber. 1 is a burner body, 2 is a combustion box, 3 is a partition plate, 4 is an intermediate burner, 5 is a primary burner, 6 is a secondary burner, 7 is a burner plate, and 8 is a primary burner. Secondary combustion air holes 9 provided on both sides are secondary combustion air holes provided on the side surface of the combustion box 2.

[0004] The flame formed in the combustion chamber 2 takes in the secondary combustion air from both sides of the primary flame hole 5 and the secondary combustion air holes 8 and 9 on the side of the combustion chamber 2 to shorten the length of the flame. We burn with stable flame.

[0005]

However, in the conventional combustion apparatus 10, the secondary combustion air holes are taken in from both sides of the primary flame hole 5 and the side of the combustion box to achieve complete combustion. Therefore, the secondary combustion air must be intensively flown into the combustion chamber 2 and the temperature of the flame rises and NOx
Did not progress.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a combustion apparatus which solves the above-mentioned problems of the conventional combustion apparatus and suppresses an increase in the generation of NOx.

[0007]

According to one aspect of the present invention, there is provided a combustion apparatus having a combustion chamber connected to a burner hole of a burner and forming a combustion chamber. A partition plate for dividing into the combustion chambers is provided, and secondary combustion air taken into each combustion chamber is taken in from above each combustion chamber.

According to a second aspect of the present invention, there is provided a combustion apparatus having a combustion chamber connected to a flame hole of a burner and forming a combustion chamber, wherein the inside of the combustion chamber is divided into a plurality of combustion chambers by a plurality of partition plates having the flame hole. It is divided and the interval between the partition plates becomes narrower toward the downstream side of the flame.

According to a third aspect of the present invention, there is provided a combustion apparatus having a combustion chamber connected to a flame hole of a burner and forming a combustion chamber, wherein each of the partition plates for dividing the inside of the combustion chamber into a plurality of combustion chambers has a flame hole. The size of the flame hole of the downstream-side partition plate is smaller than the size of the flame hole of the upstream side.

According to a fourth aspect of the present invention, in a combustion device having a combustion chamber connected to a burner hole of a burner and forming a combustion chamber, secondary combustion air taken into each combustion chamber is formed in the burner hole of the combustion chamber. The flame is introduced into the combustion chamber from a position where the recirculation of the combustion gas is reduced as much as possible.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the same components as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG.
Indicates a gas fan heater (hereinafter referred to as a hot air heater) to which the combustion device according to the present invention is applied. The hot air heater 13 has a partition 15 inside an outer case 14, and is provided with a combustion device 10 and a blower 16 inside the partition 15. An air inlet 17 is formed on the back of the outer case 14, and a warm air outlet 18 is formed on the lower front.

During the operation of the hot air heater 13, the mixed gas of the primary combustion air and the fuel supplied to the burner hole 5 of the burner burns. The air sucked in from the air inlet 17 cools the outer case 14 through the ventilation path 21 between the outer case 14 and the partition wall 15 and rises around the primary combustion chamber 22 and the combustion device 10, Primary combustion chamber 22
Then, the combustion device 10 is cooled. Part of the air that has flowed into the surroundings of the primary combustion chamber 22 flows into the combustion chamber 22 through holes formed in the lower part and the side surfaces of the flame hole 5, and becomes secondary combustion air. The flame of the flame hole 5 can be more stably burned by the secondary combustion air. The combustion gas is supplied to the ventilation passage 21 together with the cooling air flowing from the upper part of the combustion device 10.
Then, the air is blown from the hot air outlet 18 through the blower 16.

As shown in FIG. 1, the primary combustion chamber 22 of the combustion device 10 includes a Bunsen burner-type burner main body 1. On the upper side of the burner main body 1, a primary flame hole portion 5 is provided, and a large number of slit-like flame holes are arranged in the flame hole portion 5 in the longitudinal direction. Are formed. The primary combustion chamber 22 includes a metal combustion box 2 having combustion chambers 23, 24, 25 connected to the primary flame hole 5 of the burner main body 1, and a metal support plate 26 supporting the burner main body 1. Have. Partition plates 31 and 32 are provided at an intermediate portion of the combustion box 2, and three combustion chambers 23, 24 and 25 are formed by three partition plates combined with a partition plate 33 also serving as a top plate 33 of the combustion box 2. It is formed.

The first-stage combustion chamber 23 has a width (D) of the combustion box 2.
, And a secondary combustion air hole 34 is provided on both upper side surfaces. In the center of the first-stage partition plate 31, a secondary flame hole portion 37 having an opening having a width A is formed in a horizontally long rectangular shape. The height of the second-stage combustion chamber 24 is lower than the height of the first-stage combustion chamber 23 (M), and the center of the second-stage partition plate 32 is a horizontally elongated rectangular tertiary flame hole having an opening having a width B. 38 are formed. The third-stage combustion chamber 25 has a height (N) lower than that of the second-stage combustion chamber 24, and a quaternary flame hole portion having an opening having a width C in a horizontally long rectangular shape at the center of the third-stage partition plate 33. 39 are formed. The width A, B, C of each flame hole is
When the width of C is B or less and the width of B is A or less, the size of the flame hole portion of the downstream partition plate is set to be equal to or less than the size of the flame hole portion of the upstream partition plate. Height L, M, of each combustion chamber
N becomes narrower toward the downstream side of the flame, such that the height of L is M or less and the height of M is N or less.

The height of the first-stage combustion chamber 23 is, as described above, at least 1.5 times the width D of the combustion chamber 2 and the first-stage combustion chamber 23 is supplied by secondary combustion air flowing in from the side. A vortex of air is formed in the inside, making it difficult for the exhaust gas recirculation effect to occur. When the exhaust gas recirculates in the combustion chamber 23, the secondary combustion air is mixed into the flame again, and the remaining unburned gas burns again and raises the temperature of the flame. NOx is easily generated, and NOx increases.

FIG. 2 is a diagram showing the relationship between the intake of secondary combustion air and the combustion flame in each combustion chamber of such a combustion apparatus.

In the first stage combustion chamber 23, a flame is formed in the primary flame hole 5, and the secondary combustion air hole 8 in the support plate 26 is formed.
Air flows in from the air and is used as secondary combustion air. Secondary combustion air also flows in from the secondary combustion air holes 34 on the upper side surface of the first-stage combustion chamber 23. The unburned gas in the first-stage combustion chamber 23 is burned by the secondary combustion air to form a flame in the secondary flame hole 37 in the second-stage combustion chamber 24.

That is, the relationship between the amount of secondary combustion air and the flame has a relationship roughly as shown in the graph of FIG. If the supply amount of the secondary combustion air is small, an unstable flame having a long flame length is formed, resulting in incomplete combustion in which carbon monoxide is easily emitted. As the amount of secondary combustion air increases, the length of the flame gradually decreases. When the amount of secondary combustion air reaches an appropriate level, the flame becomes a stable flame with a short flame length (S region). The flame temperature at this time is about 10
00 ° C. If the amount of secondary combustion air further increases, the length of the flame becomes longer or blows off, resulting in an unstable flame. At this time, the temperature of the flame rises to around 1200 to 1300 ° C. At a temperature near this temperature, the temperature enters the temperature range of the NOx generation region (T region), and the NOx generation amount increases.

From such a relationship, if the position of the secondary combustion air hole 34 on the side surface of the combustion chamber 23 is low (close to the flame hole plate 7),
If the inflowing secondary combustion air enters the flame along the flame hole plate 7 and raises the temperature of the flame, or if there is too much space above the secondary combustion air holes, a vortex of air will form in this space. It is easy to do, causing the exhaust gas recirculation action, the flame temperature rises,
This leads to an increase in NOx.

In the second-stage combustion chamber 24, the combustion gas (flame) flowing through the secondary flame holes 37 of the first-stage partition plate 31 is not completely burned as described above.
The unburned gas contained in the flame is burned by the secondary combustion air flowing from the secondary combustion air hole 35 on the upper side surface of the combustion chamber 24. If the height M of the second-stage combustion chamber 24 is lower than a predetermined height, the supply of the secondary combustion air is extremely reduced, and there is no effect on the reduction of NOx. Therefore, this height is
For example, the height M of the combustion chamber 24 needs to be a predetermined height (1 / 4D or more) (relative to the width D). Also,
If the height of the secondary combustion air hole on the upper side surface is low, the combustion chamber 24
Exhaust gas recirculation action in the furnace raises the temperature of the flame and increases NOx
Leads to an increase in

In the third combustion chamber 25, the combustion gas (flame) flowing through the tertiary flame hole 38 of the second-stage partition plate 32 is not completely burned, but enters into the flame. The contained unburned gas is burned by the secondary combustion air flowing from the secondary combustion air holes 36 on the upper side surface of the combustion chamber 25. If the height N of the third-stage combustion chamber 25 is lower than a predetermined height, the supply of the secondary combustion air is extremely reduced, and there is no effect on the reduction of NOx. Therefore, for example, this height is lower than the height M of the second-stage combustion chamber 24, but the height N of the third-stage combustion chamber 25 is equal to the predetermined height (1 with respect to the width D). / 4
D or more). Also, if the height of the secondary combustion air holes 36 on the upper side surface is low, the third-stage combustion chamber 25
Exhaust gas recirculation action in the furnace raises the temperature of the flame and increases NOx
Leads to an increase in

In this manner, each of the flame holes 37, 38, 3
The combustion gas that has been sequentially burned in step 9 is the top plate 33 of the combustion box 2.
At the time, the unburned gas flowing out of the combustion chamber 2 through the quaternary flame hole 39, and the unburned gas remaining in the combustion gas is completely burned using the air flowing around the combustion chamber 2 as secondary combustion air. Let it. Even if the amount of secondary combustion air in this combustion is too large, since the unburned gas component is small, the temperature of the flame rises only slightly and does not lead to an increase in NOx.

The amount of the secondary combustion air flowing into the combustion chambers 23, 24, 25 of each stage depends on the widths A, B of the flame holes 37, 38, 39 of the upper partition plates of the combustion chambers 23, 24, 25. , C (FIG. 1)
) And secondary combustion air holes 34, 35, 36
The secondary combustion air amount increases when the width A, B, C or the area of the air hole is large, and decreases when the width is small. In the present invention, the required amount of the secondary combustion air is reduced toward the downstream side of the flame, and the widths A, B, and C are reduced toward the downstream side of the flame. By reducing the width, the temperature of the flame in each combustion chamber can be prevented from rising too much.

As described above, the inside of the primary combustion chamber 22 is multi-staged, and the secondary combustion air is supplied little by little to the combustion chambers 23, 24, and 25 of each stage, whereby complete combustion is performed while suppressing the temperature rise of the flame. This makes it possible to supply the secondary combustion air such that the combustion device can suppress the generation of NOx.

As described above, according to the combustion apparatus 10 of the present invention, the fuel sent to the burner main body 1 is discharged from the primary flame hole 5, and the combustion is performed in the first combustion chamber 23. A large combustion flame is formed from the primary flame hole 5 to the secondary flame hole 37, and a flame is formed in the first stage combustion chamber 23. The secondary combustion air holes 8 in the support plate 26
The secondary combustion air flows into the combustion chamber 23 through the combustion chamber 23. The secondary combustion air also flows in from the secondary combustion air holes 34 on the upper side surface to burn unburned gas.

In the secondary combustion hole portion 37, secondary combustion is performed by the secondary combustion air flowing into the first-stage combustion chamber 24 from the first-stage secondary combustion air hole 34. The remaining unburned gas is burned in the first stage combustion chamber 23.

In the tertiary flame hole portion 38, secondary combustion is further performed by the secondary combustion air flowing from the secondary combustion air hole 35 of the second stage combustion chamber 24. The remaining unburned gas is burned in the combustion chamber 24 of the stage.

Further, in the fourth flame hole portion 38, the secondary combustion air flowing from the secondary combustion air hole 36 of the third stage combustion chamber 25 and the air around the combustion chamber 2 are used as the secondary combustion air. The remaining unburned gas components are burned.

As described above, the amount of the secondary combustion air flowing from the upper side surfaces of each of the combustion chambers 23, 24, and 25 does not intensively flow into some of the combustion chambers.
Since it is possible to adjust the size of the width 39, such as the widths A, B, C, etc., it is possible to suppress the excessive temperature rise of the flame,
An increase in the occurrence of x is suppressed.

Although the present invention has been described based on one embodiment, the present invention is not limited to this. In the present invention, a three-stage combustion chamber is formed in the combustion chamber 2. However, depending on the size of the combustion chamber and the type of fuel, the number of stages is increased, and the secondary chamber is further adjusted in the combustion chamber of each stage. Combustion air may be taken in, and it is possible to obtain a combustion device in which an excessive rise in the temperature of the flame is suppressed and an increase in NOx is prevented.

[0031]

As described above, according to the first aspect of the present invention, the partition plate for dividing the inside of the combustion chamber into a plurality of combustion chambers is provided, and the secondary combustion air taken into each combustion chamber is supplied to each combustion chamber. By taking in separately, it is possible to take in stepwise without taking in intensively, and it is possible to prevent the temperature of the flame from being too high, so that it is possible to reduce the generation of NOx due to the heating of the combustion gas. .

According to the second aspect of the present invention, the interval between the partition plates is made narrower toward the downstream side in accordance with the shape of the flame which becomes smaller toward the downstream side, so that excessive secondary combustion air can be reduced. NOx can be reduced by preventing inflow and suppressing unnecessary flame spread.

According to the third aspect of the present invention, by reducing the size of the flame hole at the top of the combustion chamber of each stage, the amount of secondary combustion air taken into the combustion chamber can be suppressed. Since the size of the downstream flame hole is smaller than the size of the upstream flame hole, an excessive inflow of secondary combustion air can be suppressed, and an increase in the generation of NOx can be suppressed. it can.

According to the fourth aspect of the present invention, the secondary combustion air introduced into each combustion chamber is re-circulated from the position where the recirculation of the combustion gas of the flame formed in the flame hole of the partition plate in the combustion chamber is minimized. By taking the flame into the combustion chamber, it is possible to suppress an excessive rise in the temperature of the flame and suppress an increase in the generation of NOx.

[Brief description of the drawings]

FIG. 1 is a sectional view of a primary combustion chamber of a combustion device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between intake of secondary combustion air and combustion flame in each combustion chamber of the combustion device according to one embodiment of the present invention.

FIG. 3 is a sectional view of a gas fan heater (hot air heater) to which the combustion device according to the present invention is applied.

FIG. 4 is a graph showing a relationship between a secondary combustion air amount and a flame.

FIG. 5 is a sectional view of a conventional combustion device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Burner main body 2 Combustion box 5 Primary flame hole part 7 Flame hole plate 8 Secondary combustion air hole of support plate 10 Combustion device 13 Hot air heater 14 Outer case 16 Blower 17 Air intake 18 Hot air outlet 22 Primary combustion chamber 23 First-stage combustion chamber 24 Second-stage combustion chamber 25 Third-stage combustion chamber 26 Support plate 31 First-stage partition plate 32 Second-stage partition plate 33 Third-stage partition plate 34 Upper part of first-stage combustion chamber Secondary combustion air hole 35 Secondary combustion air hole in second-stage combustion chamber 36 Secondary combustion air hole in third-stage combustion chamber 37 Secondary flame hole 38 Tertiary flame hole 39 Quaternary flame hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihiko Kogure 1-1, Dainitsuhigashi-cho, Moriguchi-shi, Osaka Sanyo Electric Gas Equipment Co., Ltd. (72) Minoru Sugimoto 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Mitsunori Omori 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. (Reference) 3K017 AA06 AB05 AB10 AD03 AD08 AD11 AE01 AE02 AG04

Claims (4)

[Claims] 1. A combustion device having a combustion chamber connected to a burner hole of a burner and forming a combustion chamber, wherein a partition plate for dividing the inside of the combustion chamber into a plurality of combustion chambers is provided, and secondary combustion air taken into each combustion chamber is provided. Combustion device characterized by taking air from above each combustion chamber. 2. A combustion device having a combustion chamber connected to a flame hole of a burner and forming a combustion chamber, wherein the inside of the combustion chamber is divided into a plurality of combustion chambers by a plurality of partition plates having the flame hole, and A combustion apparatus characterized in that the distance between the partition plates is narrowed toward the downstream side of the flame. 3. A combustion apparatus having a combustion chamber connected to a flame hole of a burner and forming a combustion chamber, wherein each partition plate for dividing the inside of the combustion chamber into a plurality of combustion chambers is provided with a flame hole and a downstream side. A combustion device characterized in that the size of the flame hole of the side partition plate is smaller than the size of the flame hole on the upstream side. 4. A combustion device having a combustion chamber connected to a burner portion of a burner and forming a combustion chamber, the secondary combustion air taken into each combustion chamber is a combustion gas of a flame formed in the burner portion of the combustion chamber. A combustion device which is introduced into the combustion chamber from a position at which recirculation of the fuel is minimized.