JPS6211244B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a combustor that burns gaseous fuel to heat a heat exchanger and other parts, in which combustion air is supplied by a blower and a portion of the supplied air is This relates to a combustor that uses the air as primary air for premixture and burns the remaining air as secondary air.

Conventional configurations and their problems As seen in conventional gas water heaters, multiple Bunsen burners are arranged in parallel and each sucks air with a gas nozzle and mixes it with gas for combustion. There were also those that completely premixed the combustion air and fuel and supplied it with combustion, each with its own characteristics. The present invention relates to a burner that uses a blower to send air for combustion, and that forms a Bunsen flame that provides premixed air (primary air) and diffused air (secondary air). By changing the passage resistance near the outlet of the passage, the amount of premixed air can be controlled, and the premixed air ratio that matches the nature and combustion amount of the fuel to be supplied can be set arbitrarily. Secondary air is supplied from the outer periphery, giving a swirling flow to the diffused air supplied from the center, and supplying the swirling secondary air to the flame formed in the burner to create a gap between the flame and the secondary air. This forced the spread.

Conventionally, combustors using such blowers have been effective in obtaining sufficient combustion air and achieving a large amount of combustion in a compact size, but they tend to lose flame stability, and are particularly difficult to adjust the amount of premixed air (air-fuel ratio). It was difficult. Therefore, in order to accommodate many gas types and to adjust the combustion amount, electronic control is used to control the air-fuel ratio and limit the applicable gas types, making the system expensive, large, and difficult to use. Furthermore, since the flame and the secondary air were diffused by natural diffusion, the flame was elongated and spread widely, making it impossible to realize a more compact combustor. Therefore, the flame has been reduced by inserting a diffuser plate into the combustion chamber or an oxidation catalyst made of a heat-resistant oxide with catalytic action, which is expensive and requires no use of the diffuser plate or oxidation catalyst. Because the burner is fixed at a fixed position, the flame length differs depending on the gas type, making it impossible to obtain the same effect with any gas type.

Purpose of the Invention The present invention provides a combustor that uses a blower to supply premixed air and secondary air for combustion, in which the secondary air is smoothly supplied to the flame formed in the flame hole and uniformly over the entire circumference of the flame. The purpose is to stabilize the flame in the flame hole and continue stable combustion even if the amount of air in the premixture changes.

Structure of the Invention In order to achieve this object, the present invention provides a burner including a plurality of flame holes and a primary air supply port for a premixture around a premixture chamber connected to the flameholes, and Consisting of an air passage that supplies combustion air to the flame hole, a blower that blows air to the air passage, and a combustion chamber for the burner, the burner has a central air passage in the center and an outer peripheral air passage in the outer periphery. and opening the primary air supply port to the peripheral air passage,
A swirler is provided in the central air passage on the rotating shaft of the blower and has a cut-and-raised shape in the combustion direction, and a burner is provided in the center in the outer circumferential air passage between the flame hole and the primary air supply port. A partition plate having a hole is provided, and the burner is inserted into the burner port of the partition plate to form a gap near the burner hole on the outer periphery of the burner, and a plurality of two holes are formed on the circumference of the partition plate outside the gap. A combustion cylinder is provided in front of the partition plate and has an opening whose inner diameter at the tip is reduced inwardly from the secondary air supply port to form the combustion chamber. did.

With this configuration, the flame formed in the burner is tilted toward the center by secondary air supplied from the outer periphery of the burner. On the other hand, secondary air is supplied to the flame from the center of the burner in the form of a swirling flow, which induces forced diffusion between the flame and the secondary air. Therefore, the air necessary for combustion is forcibly supplied to the flame surface, making the flame shorter. Therefore, it has the effect of shortening the flame and making the combustor more compact, which is the objective of the present invention. In addition, even when the amount of air in the premixture changes and decreases, secondary air is supplied to the entire flame surface through gaps and secondary air holes, so that secondary air can be supplied to the vicinity of the flame holes. supplied,
A diffusion surface for the premixture and secondary air exists between the flame hole and the gap, and has the effect of stabilizing the flame toward the flame hole.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3.

Reference numeral 1 indicates a combustor, 2 a heat exchanger, 3 a combustion gas passage within the heat exchanger 3, 4 a downstream connection to the heat exchanger 3, and the inner diameter of the tip reduced inward, which will be described later. A combustion chamber 5 is formed by a combustion cylinder having an opening 40 inside the position of the secondary air port 30. Reference numeral 6 denotes a blower case, which is connected through a combustion cylinder 4, and includes a motor 7, rotating blades 8, a suction port 9, an outlet 10, and a fixed blade portion 11 at the bottom to form a blower 12. 13 is a ring-shaped burner with a large number of slit-shaped flame holes 14 in the upper part and a central air passage 15 in the center;
The interior is divided by a gas uniformity plate 16 and a premixture uniformity plate 17 into a gas pressure equalization chamber 18 and a premixture chamber 1.
9. A premixture pressure equalizing chamber 20 is formed, and each chamber is connected by a uniform supply means in which a plurality of uniform gas distribution holes 21 and a plurality of uniform premixture distribution holes 22 are evenly distributed and drilled. Reference numeral 23 designates a plurality of primary air supply ports equally spaced in the circumferential direction on the outer circumferential wall of the upper burner of the gas pressure equalization chamber 18 in the premixture chamber 20. 24 is a gas supply pipe to the burner 13 and opens to the gas pressure equalization chamber 18. 25 is the blower case 6 peripheral wall and burner 13
The outer circumferential air passage is composed of an outer circumferential wall of
A partition plate 2 is connected to the secondary air supply passage 26, and the other end is provided to partition the combustion chamber 5 and the outer peripheral air passage 25.
The burner 13 is inserted into the burner port 28 of No. 7, and the gap 29 between the burner 13 and the partition plate and the partition plate 2 are
7 through a secondary air port 30. Further, the central air passage 15 is connected to the outlet 10, and supplies air from the blower 12 to the center of the burner 13, and supplies secondary air for combustion to the flame 31. In the central air passage 15, the shaft center 32 of the motor 7 to which the rotary blades 8 of the blower 12 are attached is extended and exposed, and a swirler 33 cut and raised toward the direction of the combustion chamber 5 is provided at the tip. 34 fixes the burner 13 to the blade part 1
1 and constitutes the outer peripheral secondary air supply path 26. 35 faces the outer peripheral air passage 25,
At the pressure outlet provided in the blower case 6, 36 indicates an ignition electrode, 37 indicates a flame rod,
Both are attached at positions separated from each other by a constant distance from the flame hole 14. Here, the burner 13 has a flame hole portion 38 forming the flame hole 14 connected to the burner body 3.
9. The combustor 1 is configured as described above.

In the above configuration, when the power source (not shown) for operating the combustor 1 is turned on, the blower 12 starts driving, sucks air from the suction port 9, and
Discharge more. Thereafter, a portion of the air passes through the outer peripheral secondary air supply passage 26 and flows into the combustion chamber 5 from the outer peripheral air passage 25, through the gap 29, and the secondary air port 30. At that time, part of the air is transferred to the outer peripheral air passage 25
The air flows into the premixture chamber 19 through the primary air supply port 23 of the burner 13 provided in the burner 13, mixes with gas to be described later, and is ejected from the flame hole 14 as a premixture through the premixture uniform distribution hole 22. At the same time as the blower 12 is driven, the gas pressure equalization chamber 1 in the burner 13 is supplied from the gas supply pipe 24.
Gas is supplied into the flame hole 14 , flows into the premixing chamber 19 from the gas uniform distribution hole 21 , is premixed with the primary air supplied from the primary air supply port 23 , and flows into the flame hole 14 as described above. The flame 31 is ejected and ignited by the igniter 36 to form a flame 31. This flame is detected by the flame rod 37 and continues to maintain the combustion state. At this time, a part of the air from the blower 12 is supplied from the central air passage 15 as secondary air necessary for the central part of the burner 13, turned into a swirling flow by the swirler 33, and supplied to the flame 31. .

Here, the secondary air flow supplied from the gap 29 flows as shown as A in FIG.
1, while the secondary air supply port 30
The secondary air flow supplied by the secondary air flow is bent toward the opening 40 of the combustion tube 4 as shown by B in FIG.
The area ratio between the flow rates of the flame 31 which is supplied from the middle to the tip of the flame 31 is set such that the amount supplied from the secondary air supply port 30 is greater than the amount supplied from the gap 29. That is, the gap 29
If the amount of secondary air supplied is increased, flame 3
1 will be blown away, and if the amount is too small, the flame 31 will be supplied with secondary air only from the secondary air supply port 30, and the flame 31 will be
is attached to the secondary air supply port 30, resulting in combustion as shown in FIG. Therefore, the amount of air is such that the flame 31 adheres to the flame hole, and the amount of air is mainly necessary for combustion.
The secondary air is supplied from the air supply port 30.

The heat exchanger 2 is heated by the above combustion.

In the present invention having such a configuration and operation, the secondary air supplied to the center of the burner 13 is supplied to the swirler 3.
8 creates a swirling flow, so when it is supplied to the flame 31, it flows in the direction of the combustion chamber 5 and in the direction of the flame 31, so that the flow is forced toward the flame 31. This results in a state where secondary air is blown. Therefore, if there is no swirling flow, flame 3
Since secondary air is not actively supplied to the heat exchanger 1, the flame 31 extends in the direction of the heat exchanger 2, and the flame 31 touches the heat exchanger 2, which is cooled and generates CO. Next, the air supply becomes active,
Since the secondary air and the unburnt air-fuel mixture in the flame 31 are forcibly mixed, the flame 31 does not extend and becomes a short flame 31, which has the effect of eliminating the generation of CO. In addition, since the combustor 1 forcibly creates a premixture, the drop in the power supply voltage applied to the blower 11 or the pressure acting on the primary air supply port 23 may be affected by the gap 29 due to dimensional variations during mass production. ,2
If this decreases due to an increase in the area of the secondary air supply port 30, etc., the amount of primary air in the premixture may decrease. During combustion at this time, secondary air is supplied from the outer periphery to the flame 31 from the gap 29 to the base of the flame 31 as a secondary air flow A, and from the secondary air port 30 to the tip of the flame. A secondary air flow B is provided. In this way, supply from two places,
Furthermore, by providing the secondary air flow A at the base of the flame 31, a diffusion surface for the premixed air and secondary air ejected from the flame hole 14 is formed between the flame hole 14 and the gap 29. Therefore, even if the amount of primary air changes due to fluctuations in the power supply voltage during combustion or variations in mass production dimensions, the flame 31 will flow to the secondary air supply port 30 because the secondary air is supplied from the gap 29. The attached state, that is, the secondary air supply port 3 shown in FIG.
The flame 31 is not formed between the flame hole 14 and the flame hole 14, but is formed in the flame hole 14. Therefore,
Since the flame hole 31 is not formed between the secondary air supply port 30 and the flame hole 14, the partition plate 27
is not heated and does not undergo thermal deformation during combustion, so the area of the gap 29 changes and 1
Since the amount of secondary air does not change, the set combustion can be continued even if there are fluctuations in power supply voltage or dimensional variations during mass production.

Furthermore, if we look at the phenomenon in which the secondary air supplied from the central air passage by the swirler 33 described above becomes a swirling flow and is blown toward the flame 31, we can see that the
1 is blown toward the outside of the burner 13 due to the strength of the swirling flow. At this time, since secondary air is supplied from the gap 29 and the secondary air port 30, a secondary air flow is generated outside the burner 13.
Both of these phenomena occur, that is, the flame 31 is inserted toward the outside of the burner 13 by the swirling flow, but the flame 31 is
The flame 31 adheres to the flame hole 14 of the burner 13 due to the secondary air flow generated outside the burner 3 acting as a wall. Therefore, even if a swirling flow is applied, the flame 31
Even if it is pushed outward, it does not escape and adheres to the flame hole 14, so the effect of the swirling flow described above is reflected in the gap 2.
9 and without the secondary air port 30.
Further, the swirler 33 has a cut and raise in the direction of the combustion chamber 5, and is provided on the rotating shaft 32 of the motor 7 to forcibly rotate it, so that it has the effect of sucking out secondary air from the central air passage 15. Therefore, it does not become a resistance to the blower 12.

Effects of the Invention The present invention described above has the following effects.

(1) Since the flame and the secondary air supplied from the central air passage are forced to diffuse, the length of the flame becomes shorter. This means that the flame volume is smaller, providing a more compact combustor. Moreover, since a diffusion plate or an oxidation catalyst is not required in the combustion chamber, the combustion chamber becomes inexpensive, and at the same time, forced diffusion is performed regardless of the gas type, so that the same effect can be obtained regardless of the gas type.

(2) Even if the amount of air in the premixture changes while combustion continues, the flame is retained in the flame hole, and there is no abnormal heating or deformation of the partition plate due to heating, so the combustor will not burn out or become unusable. etc. will disappear.

(3) Even if there are large variations in the dimensions of each part during mass production, it does not affect the combustor, so the cost of maintaining machining accuracy during mass production can be reduced.

(4) Large variations in the dimensions of each part during mass production are acceptable because the amount of air in the premixture during combustion changes greatly, and this is due to the fact that the combustor
This means that fluctuations in the amount of air in the premixture can be large, and the combustion range of the combustor is wide.

(5) A swirler blows a swirling flow from the center of the flame, pushing the flame toward the outside of the burner, but the secondary air supplied from the gap provided around the burner and the secondary air port The flow will not form a wall and be pushed outside the burner. Therefore, the flame is fixed in the swirling flow.
Since secondary air is supplied, mixing of the flame and secondary air is further promoted and the flame becomes shorter. Also,
Since the swirler's cut-and-raise is provided toward the combustion chamber, it acts as a suction effect for the secondary air flowing through the central air passage, so it does not act as resistance to the blower.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main part of a combustor showing one embodiment of the present invention, Fig. 2 is a partial sectional view of the combustor, Fig. 3 is an enlarged plan view of the partition plate portion of the combustor, and Fig. 4 is a sectional view of the main part of the combustor showing an embodiment of the present invention. It is a sectional view of the same flame hole part. 1...Combustor, 4...Blower case, 11...
Fixed blade part, 12...Blower, 13...Burner,
14... Flame hole, 15... Central air passage, 18...
Gas pressure equalization chamber, 19... Premixture chamber, 20... Premixture pressure equalization chamber, 23... Primary air supply port, 25...
Peripheral air passage, 26... secondary air supply passage for outer periphery,
27... Partition plate, 28... Burner port, 29...
Gap, 30...Secondary air port, 32...Axis, 33
... Swirl device, 38 ... Flame hole part, 39 ... Burner body part, 40 ... Opening.

Claims (1)

[Claims] 1. A burner having a plurality of flame holes and a primary air supply port for the premixture around the outer periphery of a premixture chamber connected to the flame holes, and an air supplying air for combustion to the flame holes of the burner. The burner includes a passageway, a blower for blowing air into the air passageway, and a combustion chamber for the burner, and the burner has a central air passageway in the center and an outer peripheral air passageway in the outer peripheral part, and the first air passageway is connected to the outer peripheral air passageway.
Next, open the air supply port into the central air passage;
a partition plate provided on the rotating shaft of the blower, a swirler having a cut-and-raised direction toward the combustion chamber, and having a burner port in the center in an outer peripheral air passage between the flame hole and the primary air supply port; A gap is formed on the outer periphery of the burner by inserting the burner into the burner port of the partition plate and close to the flame hole, and a plurality of secondary air supply ports are provided on the circumference of the partition plate on the outer periphery side of this gap. A combustor is provided with a combustion tube in front of the partition plate that has an opening whose inner diameter at its tip is reduced inwardly from the secondary air supply port to form the combustion chamber.