JPH06159628A - Combustion device - Google Patents

Abstract

PURPOSE:To provide a combustion device for performing a thick and thin fuel combustion in which an input reduction can be attained without any occurrence of drain or any abnormal combustion. CONSTITUTION:In the case that a high inputting is carried out, all solenoid opening or closing valves are kept at opened states. During an intermediate inputting operation, only solenoid opening or closing valves 130 and 140 are kept open. During a low inputting operation, only the solenoid opening or closing valves 140 and 220 are opened or closed. During a minimum inputting operation, only the solenoid opening or closing valve 140 is opened.

Description

Detailed Description of the Invention

[0001]

This invention relates to NOx in exhaust gas.
The present invention relates to a combustor that performs rich-lean combustion in order to reduce

[0002]

2. Description of the Related Art A normal burner which has high input combustion (for example, No. 24) has a low input combustion (for example, No. 2.5).
In such a case, the amount of gas and the amount of air are adjusted so that the high excess air ratio (excess air ratio 3 to 4) is achieved to lower the dew point temperature of the exhaust gas and prevent the occurrence of drainage.

[0003]

However, the primary air-excessive lean air-fuel mixture is discharged from the main flame port, and the excess gas-rich rich air-fuel mixture is discharged from the sleeve flame port adjacent to the main flame port to perform rich-lean combustion. In the case of a burner that aims to reduce NOx in the exhaust gas by increasing the excess air ratio in order to prevent the occurrence of drainage in low input combustion, the primary air excess ratio of the light air-fuel mixture ejected from the main flame port will reach the combustion limit ( Primary air excess ratio about 1.
Since it exceeds 6), the lean combustion flame is blown off and combustion cannot be maintained.

An object of the present invention is to provide a combustor for performing rich / lean combustion, which can reduce the input without causing drainage or abnormal combustion.

[0005]

In order to solve the above-mentioned problems, the present invention is directed to a light air-fuel mixture which forms a main flame outlet for discharging a light air-fuel mixture in excess of primary air and sucks in primary air and gas. The main passage formed at the base end of the intake port and the sleeve flame port for discharging the rich gas mixture in excess of gas are adjacent to the side of the main flame port, and the rich air mixture intake port for inhaling the primary air and gas is provided. A combustor in which a plurality of burners each having a sub-passage formed at a base end are provided in a row, and a main nozzle and a sub-nozzle for supplying gas to each of the passages are faced to the respective suction ports, and the burner is provided with respect to the burner. The input is reduced by stopping the gas supply from the main nozzle into the main passage.

[0006]

[Operation and effect of the invention] When the gas supply to the burner from the main nozzle to the main passage is stopped in order to reduce the input amount, the combustion is stopped because the primary air excess light air-fuel mixture is not discharged from the main flame port. However, only the rich air-fuel mixture discharged from the sleeve flame mouth will burn. At this time, since only the air is discharged from the main flame port, the secondary air for combustion increases at the sleeve flame port, the excess air ratio increases, the dew point temperature of the exhaust gas decreases, and the drain is less likely to occur. In order to prevent further drainage, even if the excess air ratio is further increased, the excess gas mixture is discharged from the sleeve flame outlet, so it is discharged from the sleeve flame outlet through the auxiliary passage. The primary air excess ratio of the rich mixture does not exceed the combustion limit, and normal combustion can be maintained. In this way, since the excess air ratios of the primary air and the secondary air can be set to be large, the input amount can be reduced without causing drainage or abnormal combustion.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. In the low NOx combustor A shown in the figure, a substantially funnel-shaped light air-fuel mixture intake port 111 for inhaling primary air and gas is formed at the base end, and an air-rich light air-fuel mixture G ₁ is formed at the tip of the main flame port 1.
A main passage 11 having a substantially J-shape for discharging from 12 and a substantially funnel-shaped rich air-fuel mixture inlet 121 for sucking primary air and gas are formed at the base end, and a gas-rich rich air-fuel mixture G ₂ is provided at the tip of the sleeve. A sub-passage 12 having a substantially J shape for discharging from a flame port 122 (slit shape) is provided, and the sleeve flame port 12 is provided on both sides of the main flame port 112.
First burner block 1 in which a predetermined number of adjacent burners 10 are arranged in a row, and second burner block 2 in which similar burners 10 are arranged in a row at a ratio of, for example, 2/3 of the predetermined number.
And the first gas supply pipe 13 with the nozzle 131 facing the light mixture inlet 111 of the burner 10 of the first burner block 1.
And the second gas supply pipe 14 with the nozzle 141 facing the rich air-fuel mixture inlet 121 of the burner 10 of the first burner block 1.
And the third gas supply pipe 21 with the nozzle 211 facing the light mixture inlet 111 of the burner 10 of the second burner block 2.
And the fourth gas supply pipe 22 with the nozzle 221 facing the rich air-fuel mixture inlet 121 of the burner 10 of the second burner block 2.
And is installed in the gas water heater 700 shown in FIG. Incidentally, 701 is a heat exchanger that exchanges heat with the combustion heat of the burner 10 by passing water, and 702 is a fan for supplying combustion air to the burner 10. A proportional valve 300 is arranged in the gas supply path, and electromagnetic opening / closing valves 130, 140, 210, 220 are arranged in the branched gas supply paths, and all the electromagnetic opening / closing valves are opened at the time of a large input. When the valve is in the valve state and the medium input is applied, the solenoid opening / closing valves 130, 14
Only 0 is opened, at the time of a small input, only the electromagnetic opening / closing valves 140 and 220 are opened, and at the time of minimum input, only the electromagnetic opening / closing valve 140 is opened. still,
The electromagnetic on-off valve 140 may be omitted (directly connected).

In the present embodiment, when the fan is rotating at a predetermined speed, the primary air excess ratio on the side of the main flame port 112 is about 1.2 and the sleeve flame port 122 from a large input to a medium input.
The primary air intake damper (not shown) provided at each air-fuel mixture suction port so that the primary air excess ratio on the side becomes approximately 0.4.
The degree of opening is set, and the rich-lean combustion is performed by the lean combustion with excess combustion air and the excess gas combustion. Further, during the small input to the minimum input, the gas supply to the main flame port 112 is stopped and only the sleeve flame port 122 side is burned. At this time, the air ejected from the main flame outlet 112 through the main passage 11 acts as secondary air, and the excess air ratio due to the primary air and the secondary air increases to 3 to 4, but the air on the sleeve flame outlet 122 side is increased. Fan 702 so that the primary air excess ratio is about 0.8 or less
The rotation speed of is set.

The advantages of this embodiment will be described below. Burning the first and second burner blocks 1 and 2 (Nos. 24 to 12), burning only the first burner block 1 (Nos. 14 to 7), sleeve flame outlets of the first and second burner blocks 1 and 2. The low NOχ combustor A is changed by sequentially switching only the 122 side to combustion (No. 10 to 4) and only the sleeve flame port 122 side of the first burner block 1 (No. 5 to 1.6). The input amount can be continuously decreased from No. 24 to 1.6. Therefore, a small input (No. 7) where drainage is likely to occur
In the following cases, the rich / lean combustion is stopped and only the sleeve flame port 122 side set to gas rich (primary air excess ratio 0.4) is burned, so the secondary air amount is increased to prevent drainage. Even if the excess air ratio of the primary air and the secondary air is increased to 3 to 4, the primary air excess ratio can be suppressed to 0.8 or less, and combustion can be continued without lifting.

Up to the middle input, the light and dark combustion is performed at the main flame port 112 and the sleeve flame port 122. Moreover, since the excess air ratio is set to 3 to 4 in the combustion of only the sleeve flame port 122 performed with a small input (No. 7) or less, the flame temperature does not rise, and the generation of NOχ can be suppressed in both.

Next, a second embodiment of the present invention will be described with reference to FIG. The low NOχ combustor B shown in FIG.
A first burner block 1 in which a predetermined number of burners 10 similar to the combustor A are arranged in a row, and a second burner block 2 in which the same burners 10 are arranged in a row at a ratio of, for example, 2/3 of the above-mentioned predetermined number. The first gas supply pipe 1 with the nozzle 131 facing the light air-fuel mixture suction port 111 of the burner 10 of the first burner block 1.
3 and the second gas supply pipe 1 in which the nozzle 141 faces the rich air-fuel mixture inlet 121 of the burner 10 of the first burner block 1.
4 and the lean mixture inlet 111 and the rich mixture inlet 121 of the burner 10 of the second burner block 2 have nozzles 23 respectively.
And a third gas supply pipe 23 facing 1 and 232.
It is mounted in the gas water heater 700 shown in FIG. A proportional valve 300 is arranged in the gas supply path, and electromagnetic switching valves 130, 140, 2 are provided in the branched gas supply paths.
30 are arranged, all the electromagnetic opening / closing valves are opened at the time of a large input (No. 24), only the electromagnetic opening / closing valves 130 and 140 are opened at the time of a medium input (No. 10), and the minimum input (2.5 No.), only the electromagnetic opening / closing valve 140 is opened. In this embodiment, the solenoid opening / closing valve 1
40 may be omitted (directly connected).

Next, a third embodiment of the present invention will be described with reference to FIG. In this embodiment, the structure of the low NOχ combustor itself is the same as that of the second embodiment, but all the electromagnetic opening / closing valves are opened at the time of large input (No. 24), and the electromagnetic opening / closing at the time of medium input. Only the valve 230 is opened, and at the time of small input, the electromagnetic opening / closing valves 130, 14
Only 0 is opened, and at the minimum input (No. 2), only the electromagnetic opening / closing valve 140 is opened.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, the structure of the low NOx combustor itself is the same as that of the second embodiment, but all the electromagnetic opening / closing valves are opened at the time of the large input (No. 24), and the electromagnetic opening / closing at the time of the medium input. Only the valves 140 and 230 are opened, and at the time of the minimum input (No. 2.5), only the electromagnetic opening / closing valve 140 is opened. Also in this embodiment, the electromagnetic on-off valve 140 can be omitted (directly connected).

The low NOx combustor shown in the second to fourth embodiments has the advantage that the input amount can be continuously switched from No. 24 to No. 2.5 or less without generating drainage. The gas supply pipe and the solenoid on-off valve need only be three systems, and the structure is simple and the cost can be reduced.

Next, a fifth embodiment of the present invention will be described with reference to FIGS.
It will be described based on. The low NOx combustor C includes a burner block 3 in which a predetermined number of the same burners 10 as those in the low NOx combustor A are arranged in a row, and a first gas supply pipe in which a light air-fuel mixture suction port 111 of the burner 10 faces a nozzle 311. 31 and the nozzle 3 at the rich mixture intake port 121 of the burner 10 of the burner block 3.
The second gas supply pipe 32 facing 21 is provided and is installed in the gas water heater 700 shown in FIG. Further, electromagnetic opening / closing valves 310 and 320 are arranged in each gas supply passage, and a proportional valve 300 is arranged upstream thereof.

[To reduce the input amount] In FIG.
, As shown in FIG.
With the valve 20 open (light: dark ratio is constant at 2: 1), both the main flame port 112 and the sleeve flame port 122 burn rich and light, and the proportional valve 300 gradually reduces the gas amount (fan 702). Similarly, the electromagnetic switching valve 310 is closed at the point b, and the rotational speed of the fan 702 is increased at the point b, and only the electromagnetic opening / closing valve 320 is opened between b and d, and the burner block 3 is opened. Only the sleeve flame port 122 is kept in a combustion state, and secondary air is discharged from the main flame port 112 to set the excess air ratio to 3 to 4. Then, the proportional valve 300 reduces the gas amount to the minimum input. When the gas amount is reduced between b and d, the rotation speed of the fan 702 is gradually reduced at a rate smaller than the reduction of the gas amount, and as the input becomes smaller, the excess air ratio composed of primary air and secondary air. To prevent the occurrence of drainage. At this time, the primary excess air ratio gradually increases, but is suppressed to about 0.8 or less, so that stable combustion is achieved.

[When increasing the input amount]
, The solenoid valve 320 is opened and the burner block 3 is kept in the combustion state with only the sleeve flame port 122 between d → b, and the proportional valve 300 increases the gas amount (rotation of the fan 702). (The number is gradually increased), the electromagnetic on-off valve 310 is opened at the point b, the rotation speed of the fan 702 is decreased, and the electromagnetic on-off valves 310 and 320 are kept open between b and a (light: dark). (The ratio is constant at 2: 1) Both the main flame port 112 and the sleeve flame port 122 perform rich and lean combustion, and the proportional valve 300 gradually increases the gas amount.

When the input amount is decreased, the solenoid on-off valve 310 is opened at the point b, and at the same time, the opening of the proportional valve 300 is slightly increased to increase the supply gas amount and the input amount is increased. , The electromagnetic opening / closing valve 310 may be opened at a position where the gas amount is larger than the point b, and at the same time, the opening degree of the proportional valve 300 may be narrowed to the gas amount at the point b. As a result, it is possible to stabilize combustion when switching the opening / closing of the electromagnetic opening / closing valve 310.

This embodiment has the following advantages. When performing the rich-lean combustion by both the main flame port 112 and the sleeve flame port 122, the drainage is generated while reducing the amount of gas flowing to the first gas supply pipe 31 and the second gas supply pipe 32 by narrowing the opening of the proportional valve 300. In order to prevent it, in the method of increasing the excess air ratio by adjusting the rotation speed of the fan 702, when the input amount is small, the air-rich combustion flame formed in the main flame port 112 blows off (primary excess air ratio). Is significantly over 1.6). Therefore, with the above method, it is not possible to prevent drainage and to significantly reduce the input amount while performing good combustion. In this embodiment, when the input amount is small, the electromagnetic opening / closing valve 310 is closed, only the electromagnetic opening / closing valve 320 is opened, and the burner block 3 is set to the combustion state only in the sleeve flame port 122. By reducing the amount (b → d), the drain can be prevented and the input amount can be drastically and continuously reduced while performing good combustion. Even in a small input state (combustion of only the sleeve flame port 22), the secondary air passing through the main flame port 112 increases in combustion with a large excess air ratio (for example, 3.0), and the flame temperature lowers.
The amount of Oχ is small.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a gas water heater in which a low NOχ combustor according to a first embodiment of the present invention is mounted.

FIG. 2 is an enlarged view of a main part of a low NOχ combustor attached to the gas water heater.

FIG. 3 is a cross-sectional view of a rich / lean combustion burner which is arranged in a plurality of rows and constitutes the low NOx combustor.

FIG. 4 is a structural explanatory view of a gas water heater in which low NOx combustors according to second to fourth embodiments of the present invention are mounted.

FIG. 5 is a structural explanatory view of a gas water heater equipped with a low NOχ combustor according to a fifth embodiment of the present invention.

FIG. 6 is a graph showing the relationship between the gas amount and the input amount in the gas water heater according to the fifth embodiment.

[Explanation of symbols]

10 Burner 11 Main Passage 12 Sub Passage 111 Light Air Mixture Inlet 112 Main Flame Inlet 121 Rich Air Mixture Inlet 122 Sleeve Sleeve Flame 211 Nozzle (Main Nozzle) 221 Nozzle (Sub Nozzle) G ₁ Light Air Mixture G ₂ Rich Air Mixture A, B Low NOx combustor (combustor)

[Procedure amendment]

[Submission date] December 9, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

[Figure 6]

[Procedure amendment]

[Submission date] December 9, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

[0010] Until the middle inputs, generates the NOχ shades combustion line Do I in the main fire hole 112 and the sleeves flame holes 122
Suppress . Further, in the combustion of only the sleeve flame holes 122 performed with a small input (No. 7) or less, the excess air ratio is set to 3 to 4, so that the flame temperature can be suppressed to a low level and the generation of NOχ can be suppressed.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

[Fig. 6] Fig. 6 is a view showing the function of appliances in the gas water heater of the fifth embodiment.
It is a graph which shows the relationship between force and the amount of input.

Claims (1)

[Claims] 1. A main passage having a main flame port for discharging a light air-fuel mixture in excess of primary air formed at a tip and a light air-fuel mixture intake port for inhaling primary air and gas at a base end, and a main passage for excess gas A plurality of rows of burners each having a sleeve flame outlet for discharging a rich air-fuel mixture adjacent to the side of the main flame outlet and having a sub-passage formed at the base end of a rich air-fuel mixture suction port for sucking primary air and gas A combustor in which a main nozzle and a sub-nozzle for supplying gas to each passage are faced to each of the suction ports, and the gas supply to the burner from the main nozzle into the main passage is stopped. Combustor characterized by reducing the input depending on the situation.