JP3653376B2 - Combustion equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion apparatus in which fuel and primary air are mixed in a mixing section, and the mixture is ejected from a burner head and burned.
[0002]
[Prior art]
Conventionally, as this type of combustion apparatus, for example, as disclosed in JP-A-8-5021, a burner body, a bottomed cylindrical burner case provided on the outer periphery of the burner body, and the burner case A combustion cylinder in which a flame is formed, and a blower that is connected to the burner case and supplies combustion air to the burner body. The burner body is configured to burn from the blower. Vaporization comprising a fuel nozzle for spraying fuel while air is supplied, and a rotary atomizer for scattering and vaporizing the fuel supplied from the fuel nozzle using the centrifugal force and mixing with the combustion air A chamber is provided, and a secondary air supply passage is formed between the burner case and the burner body to branch a part of the combustion air supplied from the blower and send it into the combustion cylinder. It is.
[0003]
As shown in FIG. 4, an annular secondary air control plate 1 is provided at the end of the secondary air supply path facing the combustion cylinder, and the secondary air control plate 1 includes A plurality of secondary air ejection holes 2 having the same shape and communicating with the secondary air supply path and the combustion cylinder are provided at predetermined intervals in the circumferential direction.
[0004]
In such a conventional combustion apparatus, after heating the side wall of the vaporization chamber, fuel is sprayed into the vaporization chamber by a fuel nozzle, and primary air for combustion is supplied by a blower. Is sprayed to the inner wall of the vaporizing chamber by a rotary atomizer to vaporize by the heat of the side wall of the vaporizing chamber, generate an air-fuel mixture having a predetermined air-fuel ratio, and eject the air-fuel mixture from the burner head. A flame is formed by igniting, and the secondary air is supplied to the outer periphery of the flame via the secondary air ejection hole 2 of the secondary air control plate 1 to promote the secondary combustion of the flame. I try to let them.
[0005]
[Problems to be solved by the invention]
By the way, in the above-described combustion apparatus, usually, the combustion capacity is usually adjustable in multiple stages such as strong combustion and weak combustion.
[0006]
For example, when the combustion device is used in a heat source device such as a water heater, the required hot water temperature is high or low, or the heat device is used in a heat source device such as a hot water heater. The multi-stage combustion control described above is performed when the required heat quantity is large or small.
[0007]
Such combustion control is performed by adjusting the amount of fuel and combustion air supplied to the combustion device. In particular, the secondary air ejection holes 2 for supplying secondary air are formed to have the same diameter. Therefore, for example, when the hole diameters of these secondary air ejection holes 2 are formed to a size suitable for strong combustion, the flow velocity of the secondary air ejected from the secondary air ejection holes 2 is extremely low during weak combustion. As a result, the spread of the flame cannot be suppressed by the secondary air flow, and it is assumed that the combustion cylinder and the like are abnormally overheated.
[0008]
In order to suppress such problems, it is conceivable to increase the amount of secondary air during weak combustion, but the amount of primary air also increases as the amount of secondary air increases. The balance between the amount of air and the amount of primary air breaks down, causing problems such as lifting combustion caused by excess air and noise, which cannot be an effective means.
[0009]
The present invention has been made in view of such conventional problems, and provides a combustion apparatus that can optimally maintain the flame shape and suppress the generation of noise even when the combustion state is changed. The purpose is to do.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, a combustion apparatus according to claim 1 of the present invention includes a mixing section that mixes fuel and primary air, a burner head that burns an air-fuel mixture from the mixing section, and the burner. A plurality of secondary air injection holes arranged in a ring to supply secondary air to the outer periphery of the flame formed in the head, and the combustion capacity can be switched by adjusting the fuel supply amount and the air supply amount In the combustion apparatus described above, the secondary air ejection holes are formed by a plurality of types of large and small types of holes having different hole diameters provided alternately over the entire circumference .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3. In FIG. 1, reference numeral 10 represents a heat source unit of a hot water heating apparatus to which a combustion apparatus according to the present embodiment is applied. The heat source device 10 includes a housing 11, a hot water heater 12 provided in the housing 11, a circulation pump 13 for supplying heated water to the hot water heater 12, a reserve tank 14, and the hot water heating. And a combustion device 15 according to the present embodiment, which is attached to the vessel 12.
[0013]
Next, the combustion device 15 will be described in detail. The combustion device 15 includes a bottomed cylindrical burner casing 16 and a fan casing 17 provided outside the bottom of the burner casing 16 as shown in FIG. A combustion cylinder 18 provided continuously with the opening of the burner casing 16, a burner body 19 mounted in the burner casing 16, a blower fan 20 installed in the fan casing 17, and the fan A motor 21 is mounted outside the casing 17 and rotationally drives the blower fan 20.
[0014]
The burner body 19 is formed in a bottomed cylindrical shape, and a burner plate 22 as a burner head is attached to an intermediate portion in the axial direction so as to divide the inside into two. A large number of flame holes 22a are formed, and a space between the burner plate 22 and the bottom of the burner body 19 serves as a vaporizing chamber A serving as a mixing portion. Further, a peripheral wall forming the vaporizing chamber A is formed on the peripheral wall. Is embedded with an electric heater 23 for vaporization such as a sheathed heater for heating the peripheral wall.
[0015]
Further, through holes 19a and 16a are formed in the center of the bottom of the burner body 19 and the center of the bottom of the burner casing 16, and the air outlet 17a of the fan casing 17 is opposed to the through holes 19a and 16a. The combustion air fed from the blower port 17a is supplied as primary air to the vaporizing chamber A through the through holes 19a and 16a.
[0016]
Further, in the vaporizing chamber A, a throttle plate 24 for narrowing the air-fuel mixture flow path, which will be described later, is provided in the vicinity of the burner plate 22, and between the throttle plate 24 and the bottom of the burner body 19. Is provided with a rotary atomizer 25 that scatters fuel toward the inner wall surface of the vaporizing chamber A and stirs and mixes the primary air and vaporized fuel supplied through the through holes 19a and 16a. Yes.
[0017]
The rotary atomizer 25 is attached to the rotary shaft 26 of the blower fan 20 and is rotationally driven together with the blower fan 20.
[0018]
On the other hand, at the bottom of the burner casing 16, a plurality of secondary air supply holes 16b are formed at intervals in the circumferential direction at positions surrounding the through-holes 16a. The fan is connected via a communication hole 27 a formed in a seal member 27 interposed between the burner casing 16 and the fan casing 17 and a secondary air discharge hole 17 b formed in the fan casing 17. The casing 17 communicates with the casing 17.
[0019]
An annular accumulator chamber B is formed between the burner casing 16 and the burner body 19, and a part of the combustion air sent from the blower fan 20 is stored in the accumulator chamber B. It is designed to be supplied as secondary air.
[0020]
On the other hand, a secondary air control plate 28 is provided at the downstream end of the air storage chamber B so as to cover the end of the air storage chamber B. The secondary air control plate 28 includes Secondary air ejection holes 28a and 28b for feeding secondary air from the air storage chamber B to the front of the burner body 19 are formed.
[0021]
More specifically, the secondary air control plate 28 includes a large diameter portion 29 and a small diameter portion 30, and the small diameter portion 29 is fitted to the outer periphery of the opening of the burner body 19, A flange 29a that is brought into contact with a stepped portion 19b formed on the outer periphery and engaged with a predetermined position of the burner body 19 and that is continuously provided at the tip of the large-diameter portion 29 includes the burner casing. By being clamped at a connection portion between the burner body 16 and the combustion cylinder 18, the burner body 19 and the burner casing 16 and the combustion cylinder 18 are clamped and fixed together.
[0022]
As shown in FIG. 3, the secondary air ejection holes 28a and 28b are formed in a large number at intervals in the circumferential direction. In the present embodiment, the secondary air ejection holes 28a and 28b are formed in two types of large and small hole diameters and arranged alternately. The ratio of the opening area varies depending on the capability of the combustion device 15 and the like, but is set to 2: 1, for example.
[0023]
Further, reference numeral 31 in FIG. 2 denotes a burner thermistor attached to the side wall of the burner body 19, 32 denotes a spark plug positioned in front of the burner plate 22, 33 denotes a frame rod, and 34 denotes A fuel supply nozzle that extends from the air blowing port 17a of the fan casing 17 toward the base end of the rotary atomizer 25 and sprays fuel to the rotary atomizer 25. Reference numeral 35 denotes the fan casing 17. It is the inlet provided in the wall part.
[0024]
Next, the operation of the combustion apparatus 15 according to this embodiment configured as described above will be described. At the time of ignition, the vaporizing heater 23 is energized to heat the burner body 19, and the temperature of the burner body 19 is increased. When the temperature reaches a predetermined temperature, the blower fan 20 is driven, and fuel is supplied from the fuel supply nozzle 34 to the rotating atomizer 25 which is rotating, and this fuel is directed toward the inner wall surface of the vaporizing chamber A. It is vaporized in contact with the inner wall surface.
[0025]
On the other hand, a part of the combustion air supplied from the blower fan 20 is supplied as primary air from the blower port 17a to the vaporizing chamber A of the burner body 19 as shown by an arrow A in FIG. The fuel mixture is mixed with vaporized fuel in the chamber A, and the air-fuel mixture is discharged from the flame hole 22a of the burner plate 22 to the front of the burner body 19 through the throttle plate 24. At this time, the ignition operation by the spark plug 32 is performed. As shown by the symbol F in FIG. 2, a flame is formed in front of the burner plate 22 and combustion is started.
[0026]
On the other hand, the remaining portion of the combustion air supplied from the blower fan 20 was sent to the storage chamber B through the secondary air discharge hole 17b, the communication hole 27a, and the secondary air supply hole 16b. Later, from the outer peripheral portion toward the flame F from the secondary air ejection holes 28a and 28b formed in the secondary air control plate 28 provided on the downstream side thereof, the flame F is thereby supplied. Secondary combustion is promoted.
[0027]
Here, when the combustion is strong combustion, the supply amount of the secondary air is large. Therefore, the flow rate of the secondary air ejected from the large-diameter secondary air ejection hole 28a is fast, and the front thereof is forward. The formed flame F is narrowed down to a set range, stable combustion is maintained, and overheating of the combustion cylinder 18 due to the spread of the flame F is prevented, so that the combustion cylinder 18 can be protected. .
[0028]
Further, when the combustion is weak combustion, the flow rate of the secondary air supplied from the large-diameter secondary air ejection hole 28a is decreased by reducing the supply amount of the combustion air as a whole. However, since the secondary air ejection hole 28b having a small diameter is formed, the flow velocity of the secondary air is increased by the secondary air ejection hole 28b having a small diameter.
[0029]
Accordingly, even during weak combustion, secondary air having a sufficient flow velocity is supplied to the outer peripheral portion of the flame F, whereby the spread of the flame F is suppressed, and the above-described overheating of the combustion cylinder 18 is prevented. Thus, the combustion cylinder 18 can be protected.
[0030]
Furthermore, by ensuring the flow rate of secondary air during weak combustion, there is no need to increase the overall supply amount of combustion air, and as a result, the balance between the amount of fuel and primary air during weak combustion is balanced. As a result, the lifting combustion in which the flame F floats from the burner plate 22 is prevented, and the generation of combustion noise is suppressed.
[0031]
Note that the shapes, dimensions, and the like of the constituent members shown in the embodiment are merely examples, and can be variously changed based on design requirements and the like.
[0032]
For example, the area ratio of the large-diameter secondary air ejection hole 28a and the small-diameter secondary air ejection hole 28b is an example, and can be changed according to the required capacity for the combustion device 15, and the type of the hole diameter is also Two or more types may be used.
[0033]
Moreover, although the liquid fuel combustion apparatus which vaporizes and burns liquid fuels, such as petroleum, as one Embodiment was demonstrated, the gaseous fuel combustion apparatus which burns gaseous fuels, such as propane gas and city gas, may be sufficient.
[0034]
【The invention's effect】
As described above, in the combustion apparatus according to claim 1, the mixing portion for mixing the fuel and the primary air, the burner head for burning the air-fuel mixture from the mixing portion, and the burner head are formed. In a combustion apparatus comprising a plurality of secondary air ejection holes arranged in a ring to supply secondary air to the outer periphery of the flame, and capable of switching the combustion capacity by adjusting the fuel supply amount and the air supply amount, Since the secondary air ejection holes are formed by a plurality of large and small types of holes having different hole diameters provided alternately over the entire circumference , the amount of fuel and the amount of primary air are reduced in weak combustion. Sufficient secondary air flow rate can be secured while maintaining the balance. As a result, flame spread and lifting combustion are prevented over a wide range from strong combustion to weak combustion. It is possible to improve the durability, it is possible to suppress the occurrence of combustion noise, and, to allow the supply of uniform secondary air over the entire circumference of the outer periphery of the flame is always good and uniform combustion state can be obtained.
[Brief description of the drawings]
FIG. 1 is a front view showing a schematic configuration of a heat source machine to which an embodiment of the present invention is applied.
FIG. 2 is a longitudinal sectional view showing an embodiment of the present invention.
FIG. 3 is a front view of a secondary air control plate according to an embodiment of the present invention.
FIG. 4 is a front view of a conventional secondary air control plate.
[Explanation of symbols]
15 Combustor 16 Burner casing 18 Combustion cylinder 19 Burner body 20 Blower fan 22 Burner plate (burner head)
28 Secondary air control plate 28a Large diameter secondary air ejection hole 28b Small diameter secondary air ejection hole A Vaporization chamber (mixing section)
B Storage room F Flame

Claims (1)

A mixing section for mixing fuel and primary air, a burner head for burning the air-fuel mixture from the mixing section, and a plurality of annular arrangements for supplying secondary air to the outer periphery of the flame formed in the burner head A secondary air injection hole, and a combustion apparatus capable of switching the combustion capacity by adjusting the fuel supply amount and the air supply amount, wherein the secondary air injection holes are alternately provided over the entire circumference. Combustion device characterized by being formed of a plurality of types of holes of different sizes.

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