JPH08233216A - Combustion device - Google Patents

Abstract

PURPOSE: To provide a combustion device showing a relative trouble-free design, capable of, accommodating for many variations with a less number of components as much as possible, showing a relative easy assembling and capable of realizing a low NOx of discharged gas and a stable combustion. CONSTITUTION: A plurality of main flame gas nozzles 7, auxiliary flame gas nozzles 9 and nozzle dampers 31 are manufactured in advance in such a way that the most suitable mixing ratio for realizing a low NOx of discharged gas under each of stabilized combustion states for each of kinds of fuel of which use is expected as a fuel gas may be obtained, each of a plurality of kinds of gas nozzles 7, 9 and nozzle damper 31 which are adapted for the type of' gas used as fuel gas can be selected and fixed to the combustion device. Due to this fact, it is possible to eliminate a troublesome design operation, adapt for many variations with a less number of components, perform a relative easy assembling of the components, and realize a low NOx formation of discharged gas under a stabilized combustion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses both rich combustion, which burns with a mixture having a relatively high fuel gas concentration, and conversely, light combustion, which burns with a mixture having a relatively low fuel gas concentration. Accordingly, the present invention relates to an improvement in a combustion device capable of realizing a low concentration of nitrogen oxides (hereinafter referred to as “NOx”) in exhaust gas under stable combustion. In this specification, a combustion device of a water heater will be described.

[0002]

2. Description of the Related Art In a combustion apparatus, if light combustion is performed in order to reduce NOx in exhaust gas, it becomes difficult to realize stable combustion.
If rich combustion is performed in an attempt to achieve stable combustion, the exhaust gas will have low N
It is known that it is difficult to achieve Ox conversion.

Therefore, a plurality of combustion sections, each of which is composed of a light combustion burner which forms a main flame and a rich combustion burner which forms an auxiliary flame for stabilizing the main flame, are arranged in parallel, and each light combustion burner has a fuel gas. Combustion device in which a main flame gas nozzle that supplies fuel gas from a supply source to a lean combustion burner and an auxiliary flame gas nozzle that supplies fuel gas to the rich combustion burner are adjacent to each rich combustion burner Was proposed.

[0004]

By the way, in the above device, combustion can be carried out at an optimum mixing ratio according to the gas species of the fuel gas, that is, low NOx of the exhaust gas under stable combustion.
In order to realize this, each burner is configured such that a fixed amount of fuel gas is supplied through a gas nozzle and a fixed amount of primary air is supplied through an air fan.

However, the above-mentioned device requires not only the parts specific to each gas type, but also the internal structure of the device is different for each gas type, so that the gas type that will be used as the fuel gas It takes a lot of time to design because it is necessary to design it. Also, since it is necessary to prepare parts for each gas type, the number of parts must be increased. Further, there is a drawback that the assembly work becomes complicated because the parts used for each gas type and the internal structure are different.

Therefore, an object of the present invention is to achieve relatively low design, relatively large number of valuations with as few parts as possible, and relatively easy to assemble, low exhaust NOx and stable combustion. The object of the present invention is to provide a combustion device that can do so.

[0007]

In order to achieve the above object, a first aspect of the present invention relates to a first burner that forms a main flame with a mixture having a relatively low fuel gas concentration, and a fuel gas concentration In a combustion device including a second burner that forms an auxiliary flame for stabilizing the main flame with a relatively rich air-fuel mixture, a first fuel gas provided close to the air-fuel mixture introduction portion of the first burner. A supply nozzle and a second fuel gas supply nozzle provided in the vicinity of the air-fuel mixture introducing portion of the second burner, and the diameter of each fuel supply nozzle is set according to the gas type of the fuel gas. It is characterized by being.

In order to achieve the above object, the second aspect of the present invention
In the combustion apparatus according to claim 1, the side surface of (1) controls the amount of primary air flowing into the air-fuel mixture introducing portion of each burner in the vicinity of each fuel supply nozzle to an amount suitable for the gas species of the fuel gas. Is provided with a primary air inflow amount control member having a through hole formed therein.

In order to achieve the above object, a third aspect of the present invention is provided.
The side surface of the first burner forms a main flame with a mixture having a relatively low fuel gas concentration, and the second burner forms an auxiliary flame for stabilizing the main flame with a mixture having a relatively high fuel gas concentration. In a combustion apparatus comprising: a gas pipe that individually connects between each burner and a fuel gas supply source, each gas pipe, a valve mechanism provided for adjusting the fuel gas supply amount, And the opening degree of each of the valve mechanisms is controlled according to the gas type of the fuel gas.

[0010]

According to the first aspect of the present invention, the caliber of the first fuel gas supply nozzle and the caliber of the second fuel gas supply nozzle are optimized in advance for each gas type that will be used as the fuel gas. It is manufactured so that a mixing ratio can be obtained, and one that is suitable for the gas species used as the fuel gas from these fuel gas supply nozzles, that is, low N of exhaust gas under stable combustion.
Since a nozzle that can realize Ox can be selected and attached to the device, it is relatively easy to design, can handle many valuations with a small number of parts, is relatively easy to assemble, and has stable combustion. Low NOx in the exhaust under
Can be realized.

According to the second aspect of the present invention, the first and second aspects are provided.
The diameter of the through hole of the primary air amount control member provided in the vicinity of the fuel supply nozzle is manufactured in advance so that an optimum mixing ratio can be obtained for each gas type that will be used as the fuel gas, From these primary air amount control members,
It is relatively easy to design because it is possible to select the one that is suitable for the type of gas used as the fuel gas, that is, the one that can realize low NOx emission under stable combustion, and install it in the device. It can support many valuations with a small number of parts, is relatively easy to assemble, and realizes low NOx emission under stable combustion.

According to the third aspect of the present invention, the opening degree of the valve mechanism provided for adjusting the fuel gas supply amount in the gas pipes that individually connect the burners and the fuel gas supply source is adjusted. Since it is controlled according to the type of fuel gas, it is relatively easy to design, can handle many valuations with a small number of parts, is relatively easy to assemble, and is stable in combustion. The NOx of the exhaust gas can be reduced.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings.

First, as one embodiment of the present invention, a combustion apparatus applied to a water heater as shown in FIGS. 1 to 9 will be described.

As shown in FIGS. 1 to 3, the above-mentioned apparatus comprises a plurality of burners 1 capable of rich and lean combustion, an air introducing section 3 in which the burners 1 are arranged in parallel, and a gas manifold adjacent to the air introducing section 3. 5. As shown in FIG. 9, a plurality of main flame gas nozzles 7 and a plurality of auxiliary flame gas nozzles 9 are provided, the base portion of which is fixed to the gas manifold 5 and the tip portion of which is provided close to each burner 1. An air introduction fan 11 connected to the introduction unit 3 is provided.

As shown in FIG. 6, each burner 1 has an inner space portion 14 of a light burn burner 13 and a rich burn burner 15.
The outer space portion 1 of the rich combustion burner 15 with the one plate-shaped member formed with the upper portion of the light combustion burner 13 sandwiched therebetween.
And two cover members for forming 6. The light combustion burner 13 is formed in a substantially U-shape on the side surface of the plate-like member with a predetermined bulge so that the air-fuel mixture for forming the main flame can be introduced. Similarly, the inner space portion 14 of the rich combustion burner 15 is also formed in a substantially L-shape on the side surface of the plate member so as to have a predetermined bulge so that the air-fuel mixture for forming the auxiliary flame can be introduced. (Figs. 4 to 6)
reference).

A substantially elliptical air-fuel mixture inlet 17 is provided at the end of the lean burner 13 on the air introducing portion 3 side, and the heat exchanger 27 shown in FIG. 2 is heated at the upper end. In order to do so, a plurality of main flame outlets 19 formed in slits are arranged in parallel. In order to introduce the air-fuel mixture having a relatively low fuel gas concentration into the air-fuel mixture inlet 17, the tip portion of the main flame gas nozzle 7 having a shape as shown in FIG. 8 faces.

A substantially circular air-fuel mixture inlet 21 is provided at the end of the rich combustion burner 15 on the side of the air introducing portion 3 in the inner space, and the upper end of the outer space is shown in FIG. In order to heat the heat exchanger 27 shown, a plurality of auxiliary flame outlets 23 formed in a substantially rectangular shape are arranged in parallel.
In order to introduce the air-fuel mixture having a relatively high fuel gas concentration into the air-fuel mixture inlet 21, the tip of the auxiliary flame gas nozzle 9 having a shape as shown in FIG. 8 faces. The inner space 14 of the rich combustion burner 15 is provided with a plurality of small holes 25 for communicating with the outer space 16 of the rich combustion burner 15.

In one embodiment of the present invention, the diameters of the main flame gas nozzles 7 and the auxiliary flame gas nozzles 9 described above are set so that a fuel flow rate suitable for the gas species used as the fuel gas can be obtained. Has been done. In addition, in the vicinity of the tips of the main flame gas nozzles 7 and the auxiliary flame gas nozzles 9, the primary air flowing into the air-fuel mixture inlet 17 of each light burner 13 and the air-fuel mixture inlet 21 of each rich burner 15 is introduced. A nozzle damper 31 having a plurality of through holes 29 as shown in FIG. 7 is provided in order to control the amount so as to match the gas type used as the fuel gas.

FIG. 5 is a diagram showing the positional relationship between each of the above-mentioned burners 1, the air introducing portion 3 and the gas manifold 5. In FIG. 5, the bottom surface portion 33 of the air introduction portion 3
Also, the pair of burner holding portions 35 provided in the middle stage have a large number of secondary air introduction holes required to introduce secondary air in addition to the primary air introduced to form the air-fuel mixture together with the fuel gas. 37 is formed.

The above-mentioned main flame gas nozzle 7 and auxiliary flame gas nozzle 9 and the nozzle damper 31 are respectively optimally mixed with each other according to the gas type expected to be used as the fuel gas, as shown in Table 1 below. A plurality of types of gas nozzles 7 are manufactured in advance so that the ratio can be obtained.
9 and the nozzle damper 31, the ones suitable for the gas species used as the fuel gas are selected and attached to the above device.

[0022]

[Table 1] In Table 1, the primary air ratio m1 of each gas type is obtained by m1 = primary air amount / theoretical air amount (1), and the theoretical air amount is proportional to the gas amount.

In the present embodiment, when the primary air ratio m1 of each gas type is calculated by the equation (1), the condition for realizing the low NOx of the exhaust gas under stable combustion is, for example, the primary air ratio m1 = Based on 0.5, the primary air amount / gas amount is multiplied by 0.5. That is, for example, the primary air ratio m1 during light combustion of gas species is
The ratio of the amount of gas and the amount of primary air during light combustion is 60:80
Therefore, m1 = 0.5 × 80/60 = 0.67, and the ratio of the gas amount and the primary air amount during rich combustion is 40:
Since it is 20, m1 = 0.5 × 20/40 = 0.25
Is. In the same manner, the primary air ratio m1 of the gas species can be obtained during light combustion and during rich combustion.

It can be said from Table 1 that the primary air ratio m1 decreases as the gas amount increases, and the primary air ratio m1 increases as the gas amount decreases, based on the above 0.5. The primary air amount is opposite to the above. However, the numerical value of the primary air ratio shown in Table 1 is an example at a certain combustion amount,
Actually, it changes with the control of the combustion amount and the air amount.

Next, when the primary air ratio m1 in the light combustion is increased, when the light combustion amount is increased (the rich combustion amount is decreased), the light combustion amount and the light combustion primary air ratio m1 are increased. In this case, the case where the primary air ratio m1 of light combustion is reduced will be described.

(A) When the primary air ratio m1 is increased in the light combustion When the primary air ratio m1 is increased by changing the gas used from the gas type to the gas type, the light combustion burner is passed through the gas manifold 5. Since it is only necessary to change the distribution amount of the gas supplied to each of the gas burner 13 and the rich combustion burner 15, only the nozzle diameters of the main flame gas nozzle 7 and the auxiliary flame gas nozzle 9 need to be replaced with those suitable for the gas species. Becomes
In this case, in lean combustion, the primary air ratio m1 increases because the gas amount decreases, and in rich combustion, the primary air ratio m1 decreases because the gas amount increases.

(B) When the primary air ratio m1 is increased When the primary air ratio m1 is increased by changing the gas used from the gas type to the gas type, the air is introduced through the air introduction section 3 and the rich combustion burner 13 Since it is only necessary to change the distribution amount of the primary air supplied to the combustion burner 15, the nozzle damper 31 may be replaced with the nozzle damper 31 in which the diameters of the plurality of through holes 29 are adapted to the gas type. In this case, in lean combustion, the primary air amount increases and the primary air ratio m1 increases, and in rich combustion, the primary air amount decreases and the primary air ratio m1 decreases.

(C) Increase the amount of light combustion (decrease the amount of rich combustion)
When the gas used is changed from gas type to gas type to increase the lean burn amount, the primary air ratio m1 on the lean burn side does not change, and the lean burn burner 13 and the rich burn burner 15 respectively Since it is necessary to change both the distribution amount of the supplied gas and the distribution amount of the primary air, the nozzle diameters of the main flame gas nozzle 7 and the auxiliary flame gas nozzle 9 are replaced with those suitable for the gas species, and the nozzle damper 31 is used. Also, it is necessary to replace the nozzle damper 31 with the diameter of the plurality of through holes 29 adapted to the gas type. In this case, the gas amount and the primary air amount increase in the light combustion, and the gas amount and the primary air amount decrease in the rich combustion.

(D) Light burn amount and light burn primary air ratio m
When 1 is increased When the gas used is changed from gas type to gas type and the light burn amount and the primary air ratio m1 of light burn are increased,
Since it is necessary to change both the distribution amount of the gas and the distribution amount of the primary air supplied to the light combustion burner 13 and the rich combustion burner 15, respectively, the main flame gas nozzle 7 and the auxiliary flame gas nozzle 9 are required.
It is necessary to replace the nozzle diameter of No. 1 with a nozzle suitable for the gas type, and also replace the nozzle damper 31 with a nozzle damper 31 in which the diameters of the plurality of through holes 29 are compatible with the gas type. In this case, the gas amount and the primary air amount increase in the light combustion, and the gas amount and the primary air amount decrease in the rich combustion.

(E) Light burn amount and light burn primary air ratio m
When 1 is increased When the gas to be used is changed from gas type to gas type and the light burn amount and the primary air ratio m1 of the light burn are increased, they are supplied to the light burn burner 13 and the rich burn burner 15, respectively. Since it is necessary not only to change the distribution amount of gas, but also to change the distribution amount after increasing the absolute amount of primary air, the nozzle diameters of the main flame gas nozzle 7 and the auxiliary flame gas nozzle 9 are changed to gas. Replace with one that matches the seed,
As for the nozzle damper 31, it is necessary to replace the nozzle damper 31 with a nozzle damper 31 in which the diameters of the plurality of through holes 29 match the gas species. In this case, the gas amount and the primary air amount increase in the light combustion, and the gas amount and the primary air amount decrease in the rich combustion.

(F) When the primary air ratio m1 of the light combustion is reduced: When the gas used is changed from the gas type to the gas type and the primary air ratio m1 of the light combustion is reduced, the absolute amount of the primary air is reduced. Since it is necessary to reduce the distribution amount of the primary air supplied to the light burner burner 13 and the rich burner burner 15 respectively, the nozzle damper 31 should be a nozzle damper in which the diameters of the plurality of through holes 29 are adapted to the gas species. You need to replace it with 31. In this case, the amount of gas does not change in both light and dark combustion.

(G) Regardless of which of the above gas types is used as the fuel gas, it is possible to satisfy the conditions for realizing low NOx emission under stable combustion by performing rich / lean combustion. However, in the case of a gas species having a high burning rate, the above condition may not be satisfied under rich and lean combustion. Gas species are shown as an example. That is, with respect to the gas type, it is not possible to distinguish between the light combustion and the rich combustion, as is apparent from Table 1.

According to the above arrangement, the rich and lean combustion can be adjusted independently. For example, in the case of a gas type that generates a large amount of NOx, the inner diameter of the main flame gas nozzle 7 that is a light combustion nozzle is increased to increase the light combustion amount, or the rich combustion is increased to increase the primary air amount of the rich combustion. By reducing the outer diameter of the auxiliary flame gas nozzle 9 that is a working nozzle or by increasing the diameter of the through hole 29 on the rich combustion side of the nozzle damper 31, the range of the stable combustion region can be widened. On the contrary, in the case of a gas species with a small NOx generation amount, the inner diameter of the main flame gas nozzle 7 is reduced to reduce the light combustion amount, and the main flame gas nozzle 7 is reduced to reduce the primary air amount of the light combustion. By increasing the outer diameter or decreasing the diameter of the through hole 29 on the light combustion side of the nozzle damper 31, the range of the stable combustion region can be widened.

According to the above construction, the main flame gas nozzle 7 and the auxiliary flame gas nozzle 9 and the nozzle damper 31 are used to reduce NOx in the exhaust gas under stable combustion for each gas type expected to be used as fuel gas. A plurality of types are manufactured in advance so as to obtain an optimum mixing ratio to realize the gas mixture, and the gas nozzles 7 and 9 and the nozzle damper 31 of the plurality of types are
Since it is possible to select ones that are compatible with the type of gas used as fuel gas and attach them to the above-mentioned device, it is relatively easy to design, can support many valuations with a small number of parts, and can be assembled. Reducing NOx in exhaust gas under stable combustion can be realized relatively easily.

FIG. 10 shows a fuel gas piping system of a combustion apparatus according to another embodiment of the present invention.

In the present embodiment, the distribution ratio of the amount of fuel supplied to both the rich and lean combustion burners is a value that can realize low NOx emission under stable combustion regardless of the type of gas used and the amount of gas used. Therefore, the opening degree of the proportional valve 55 of the gas pipe 53 connected to the main flame gas nozzle 51 and the opening degree of the proportional valve 61 of the gas pipe 59 connected to the auxiliary flame gas nozzle 57 are controlled.

Also in this embodiment, the same effect as in the above-mentioned embodiment can be obtained. In FIG. 10, reference numerals 63 and 65 are electromagnetic valves, reference numeral 67 is a main pipe of a gas pipe, reference numeral 69 is an original solenoid valve provided in the main pipe 67, and reference numerals 71 and 73 are gas nozzles 51 and 57, respectively. It is a gas manifold.

It should be noted that the above contents are only related to the embodiments according to the present invention, and it does not mean that the present invention is limited to the above contents.

[0039]

As described above, according to the present invention,
It is possible to provide a combustion device that requires relatively few designs, can handle a large number of valuations with as few parts as possible, and that can achieve low NOx emission and stable combustion that are relatively easy to assemble.

[Brief description of drawings]

FIG. 1 is a partial side view of a burner according to an embodiment of the present invention.

FIG. 2 is a partial front view of a combustion device including a plurality of burners shown in FIG.

3 is a partially enlarged front view of FIG.

4 is a perspective view of the burner shown in FIG. 1. FIG.

5 is a perspective view of an air introducing portion in which a plurality of burners in FIG. 1 are arranged in parallel.

FIG. 6 is a perspective view showing an internal configuration of the burner shown in FIG.

FIG. 7 is a partial plan view of a nozzle damper.

FIG. 8 is a perspective view of a gas nozzle.

FIG. 9 is a partial plan view of a portion of the gas manifold where a plurality of gas nozzles are provided.

FIG. 10 is an explanatory diagram showing a fuel gas piping system of a combustion device according to another embodiment of the present invention.

[Explanation of symbols]

 1 Burner 3 Air Introducing Section 5 Gas Manifold 7 Light Combustion Gas Nozzle 9 Rich Combustion Gas Nozzle 11 Air Fan 13 Light Combustion Burner 15 Rich Combustion Burner 17, 21 Mixture Introducing Section 19 Main Flame Outlet 23 Auxiliary Flame Outlet 29 Through Hole 31 nozzle damper

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Joji Arita 43-1, Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo Nihon Yupro Co., Ltd. (72) Inventor Yoshinori Shichi 43-1, Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo Issue Nihon Yupro Co., Ltd. (72) Inventor Keiji Adachi 43-1, Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo Prefecture Nihon Yupro Co., Ltd. (72) Inventor Kunihiko Nakano 43-1, Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo Prefecture Issue Nihon Yupro Co., Ltd.

Claims (3)

[Claims] 1. A first burner which forms a main flame with a mixture having a relatively low fuel gas concentration, and a second burner which forms an auxiliary flame for stabilizing the main flame with a mixture having a relatively high fuel gas concentration. In a combustion device including a burner, a first fuel gas supply nozzle provided in the vicinity of the air-fuel mixture introducing portion of the first burner, and a first fuel gas supply nozzle provided in the vicinity of the air-fuel mixture introducing portion of the second burner. 2 fuel gas supply nozzles, and the diameter of each of the fuel supply nozzles is set according to the gas species of the fuel gas. 2. The combustion device according to claim 1, wherein the amount of primary air flowing into the air-fuel mixture introducing portion of each burner in the vicinity of each fuel supply nozzle is controlled to an amount suitable for the gas type of the fuel gas. A combustor comprising: a primary air inflow control member having a through hole formed therein. 3. A first burner which forms a main flame with a mixture having a relatively low fuel gas concentration, and a second burner which forms an auxiliary flame for stabilizing the main flame with a mixture having a relatively high fuel gas concentration. In a combustion apparatus including a burner, a gas pipe that individually connects each of the burners and a fuel gas supply source, and a valve mechanism provided in each of the gas pipes to adjust a fuel gas supply amount. The opening degree of each of the valve mechanisms is controlled according to the gas type of the fuel gas.