JPH0737841B2 - Combustion device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a domestic or commercial combustion device such as a heating appliance.

2. Description of the Related Art In recent years, in combustion devices, efforts have been made to expand the variable range of the combustion amount while improving the exhaust gas characteristics. As one of the means, we have succeeded in greatly improving the above characteristics by using a combustion device in which a large number of flame nozzles face each other.

An example of the above-described combustion device will be described below with reference to the drawings.

FIG. 6 to FIG. 8 show a conventional combustion device using an opposing flame.

Reference numeral 31 is a fuel nozzle for ejecting fuel, 32 is a vaporizing cylinder for vaporizing the fuel, 33 is a heater for heating the vaporizing cylinder, 34 is a mixing chamber for mixing vaporized fuel and air, 35 is a fuel passage, and 36 is a fuel passage. Forked fuel supply path, 37 flame outlet, 38 combustion chamber wall, 39
Is a flame and 40 is a combustion chamber. 41 is a side plate on the opposite side of the mixing chamber 34, 42 is a secondary air supply pipe, and the secondary air is allowed to flow through a through hole 43 formed in the side plate 41. Reference numeral 44 is a burner cover that covers the outside of the fuel passage, and the space between the burner cover 44 and the fuel passage 35 is a secondary air chamber 45. Reference numeral 46 is a cover that covers the space between the burner cover 44 and the combustion chamber wall 38, which has a secondary air supply port 47 formed therein, and supplies secondary air upward from the combustion chamber between the burner cover 44 and the upper end of the combustion chamber wall. A gap 48 is formed.

The operation of the combustion device configured as described above will be described below.

First, when the heater 33 is energized and the vaporization cylinder 32 reaches a predetermined temperature, combustion air and liquid fuel are sent into the vaporization cylinder 32,
The liquid fuel is vaporized by the vaporization tube 32 and is sent to the mixing chamber 34 while being mixed with air, and the air and the vaporized fuel are sufficiently mixed in the mixing chamber 34. The mixed air-fuel mixture passes through the fuel passage 35 and reaches the flame port 37 from the multiple fuel supply passages 36. Flame mouth
When the air-fuel mixture ejected from 37 is ignited, a flame 39 is formed, and the secondary air is supplied mainly from the secondary air port 47 during strong combustion and from the gap 48 during weak combustion and burns. Here, since the flame ports 37 are provided to face each other, the flame
39 are formed facing each other as shown in FIG. as a result,
Even when the amount of air is increased or the amount of combustion is large, it is very difficult for the flame to blow off, and the variable range of the amount of air and the amount of combustion is widened.

However, in the above-described configuration, the vertical wall portion 46a of the cover 46 is abnormally heated by the radiant heat from the secondary flame 39a formed above the combustion chamber, and therefore, is used for a long period of time. If so, this portion is deformed and the size of the gap 48 is changed, so that the amount of secondary air supplied from this gap is increased and CO is likely to be generated during weak combustion. Also this gap 48
Since the vertical wall portion 46a forming the above and the combustion chamber wall 38 are flush with each other, the secondary flame formed in this gap 48 portion has a gap of the above-mentioned gap 48 in accordance with a subtle change in the secondary air jet pressure. There is also a problem that it becomes unstable, such as being attached to or separated from the opening edge.

The present invention has been made in view of such a point, and an object thereof is to suppress the generation of CO during weak combustion and to stabilize the secondary flame.

Means for Solving the Problems In order to achieve the above object, the present invention forms a combustion chamber by facing two surfaces of a combustion chamber wall having a large number of flame openings, and a secondary air chamber is provided outside the combustion chamber. An outer flange is formed at the upper end of the combustion chamber wall, and a plurality of secondary air holes are formed above the flange, and an outward inclined wall and a vertical wall connected to these. And a vertical wall portion of the cover is arranged outside the combustion chamber wall, and a secondary air chamber is provided between the lower end of the vertical wall portion of this cover and the flange portion. A heat insulating plate is provided on the upper surface of the flange at the upper end of the combustion chamber wall to communicate with the vertical wall of the cover with a cooling gap covering the vertical wall. It is positioned outside the combustion chamber wall so as to form a step on the upper part of the chamber wall, and a large number of through holes are provided. The secondary air is supplied to the upper part of the combustion chamber together with the secondary air holes.

Action According to the present invention, the radiant heat of the vertical wall from the secondary flame is blocked by the heat shield plate by the above configuration, and the heat shield plate and the vertical wall portion are cooled by the secondary air flowing through the cooling gap between them. Therefore, the thermal deformation of this portion is small. Even if the vertical wall is deformed or the heat shield plate that is likely to reach a relatively high temperature is deformed, the secondary air is supplied through the through hole formed in the heat shield plate. The amount (opening area) does not change, and therefore the secondary air can be continuously supplied as designed and the generation of CO can be suppressed. Moreover, since the heat shield plate is located slightly outward of the combustion chamber wall and forms a step on the upper part of the combustion chamber wall, a part of the secondary flame comes to adhere to this step. The next flame is also stable.

Embodiment One embodiment of the present invention will be described below with reference to the accompanying drawings. In FIGS. 1 to 5, 1 is a vaporization tube for vaporizing liquid fuel, 2 is a fuel nozzle for ejecting the liquid fuel into the vaporization tube 1, which is in communication with a pump. Reference numeral 3 denotes an air passage for guiding the combustion air from the blower to the vaporization cylinder 1, which is opened at the inlet of the vaporization cylinder 1 together with the fuel nozzle 2. A mixing chamber 4 is provided at the outlet of the vaporization cylinder 1 and communicates with the fuel passages 5 on both sides. A large number of fuel supply passages 6 are branched from the fuel passage 5, and the other end of the fuel supply passage 6 penetrates the combustion chamber wall 7 and opens into the combustion chamber 8 to form a flame port 9. Here, the two combustion chamber walls 7 face each other, and the flame ports 9 are provided at positions facing each other. Reference numeral 10 is a flame formed in the flame port 9, and the flames 10 from both sides face each other. Further, the fuel passage 5, the fuel supply passage 6 and the combustion chamber wall 7 are formed by a burner body 11 formed by bending one sheet metal, and a plurality of burner bodies 11 are connected to each other. A flange portion 7a is formed on the upper end of the combustion chamber wall 7 by bending outward. Reference numeral 12 is a side plate that fixes the burner body 11 and the vaporization cylinder 1 on the opposite side of the mixing chamber 4, 13 is a secondary air supply pipe, and the burners 11 are connected to each other via a through hole 14 formed in the side plate 12. Secondary air is made to flow into the space. Reference numeral 15 is a burner cover that covers the outside of the fuel passage 5 of the burner body 11, and the space between the burner bodies serves as a secondary air chamber 16. Reference numeral 17 is a cover for covering a space between the burner cover 15 and the combustion chamber wall 7, and as shown in FIG. A wall portion 17b, a vertical wall portion 17a is located outside the combustion chamber wall 7, and a lower end of the vertical wall portion 17a is arranged so as to form a constant gap 19 on the flange portion 7a at the upper end of the combustion chamber wall 7. I am doing it. Reference numeral 20 denotes a heat shield plate attached to the upper end of the combustion chamber wall 7 by spot welding or the like. In this embodiment, the heat shield plate is formed in a shape and a heat shield portion 20a is provided upright on the upper end of the collar portion 7a.
The heat shield 20a of the heat shield plate 20 is located slightly outside the combustion chamber wall 7 to form a step 21 at the upper end of the combustion chamber wall, and a cooling gap is formed between the cover 17 and the vertical wall 17b. 22 is formed, and a large number of through holes 23 are formed in the lower part thereof, the through holes 23 having an area for supplying an optimum amount of secondary air during weak combustion.
In addition, 24 is an ignition electrode for igniting the air-fuel mixture, and 25 is a vaporization cylinder 1
It is a heater embedded in.

The operation of the combustion device configured as described above will be described below.

First, the heater 25 is energized to heat the vaporization cylinder 1. When the vaporization cylinder 1 reaches a predetermined temperature, the blower is operated and the combustion air is sent to the vaporization cylinder 1 through the air passage 3. Further, the pump also operates, and the fuel flows from the fuel nozzle 2 to the vaporization cylinder 1
Gush out inside. Since the vaporization cylinder 1 is at a temperature at which the liquid fuel vaporizes, the fuel is vaporized and introduced into the mixing chamber 4 from the outlet of the vaporization cylinder 1 while being mixed with the combustion air as shown by the broken line arrow in FIG. In the mixing chamber 4, the fuel and air become a uniformly mixed mixture and flow into the fuel passage 5 as shown by the solid arrow in FIG. Further, the air-fuel mixture advances from the fuel passage 5 to the fuel supply passage 6 branched into a large number, and the air-fuel mixture emitted from the opening of the combustion supply passage 6, that is, the flame port 9 is ignited by the ignition electrode.
When ignited by 24, flame 10 is formed and combustion continues. At this time, secondary flames 10A '(during strong combustion) and 10A "(during weak combustion) are formed in the upper part of the combustion chamber 8 as shown in FIG. Mainly, a large amount of secondary air X from the secondary air hole 18 is obtained to perform combustion, and the secondary flame 10A ″ during weak combustion is a small amount of secondary air Y from the through hole 23.
To obtain and burn.

Although considerable radiant heat is radiated from the secondary flames 10A ′, 10A ″ toward the cover 17 side, the secondary air holes 18
The vertical wall portion 17b of the cover 17 that is not affected by the cooling / heat shielding effect of the secondary air ejected from the heat shield plate 20 is shielded from the radiant heat by the heat shield portion 20a of the heat shield plate 20, and the space between this heat shield portion 20a and Since the formed cooling gap 22 is cooled by a part of the secondary air flowing as shown by the arrow a, the temperature is maintained at a relatively low temperature, and the conventional thermal deformation is hardly caused. Moreover, the temperature increase of the heat shield 20a covering the vertical wall 17b is suppressed by the cooling effect of the secondary air, and the thermal deformation of the heat shield 20a is reduced. Even if the vertical wall portion 17b is deformed or the heat shield portion 20a is thermally deformed to some extent, the secondary air that greatly affects the combustion during the weak combustion is passed through the through holes 23 formed in the heat shield portion 20a. Since the amount of air (opening area) does not change, the secondary air continues to be supplied as designed to suppress the generation of CO and ensure good combustion over a long period of time. It is possible. The secondary flame 10A '(10A ") formed in the upper portion of the combustion chamber 8 has the step 21 formed in the secondary air supply through hole 23 in the upper portion of the combustion chamber.
10A ′ (10 ″) is easily attached to this step portion 21. Therefore, even if the ejection pressure of the secondary air supplied from the through hole 23 changes slightly due to the uneven rotation of the blower due to voltage fluctuations, etc. The next flame 10A '(10A ") is always formed by adhering to this step portion 21 and is stable.

In addition, although the above-described embodiment has been described with respect to the combustion device using the liquid fuel, the gas fuel may be used, and in this case, the vaporizing cylinder is simply a mixing pipe.

EFFECTS OF THE INVENTION As is clear from the above description of the embodiments, according to the combustion apparatus of the present invention, it is possible to prevent thermal deformation of the secondary air supply portion in the upper part of the combustion chamber and suppress CO generation during weak combustion. In addition, the secondary flame can be attached to the step portion of the upper part of the combustion chamber to be stabilized, and good combustion can be obtained for a long period of time.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a combustion apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view thereof, FIG. 3 is an enlarged sectional view of the main portion thereof, and FIG. 4 is AA ′ of FIG. A sectional view, FIG. 5 is a sectional view taken along the line BB ′ of FIG. 4, FIGS. 6 to 8 show a conventional example, FIG. 6 is a sectional view of a combustion device, and FIG. 7 is C of FIG. -C 'sectional view, FIG. 8 is a DD' sectional view of FIG. 7 ... Combustion chamber wall, 7a ... Collar part, 8 ... Combustion chamber, 9 ... Flame port, 16 ... Secondary air chamber, 17 ... Cover, 17a ... Inclined wall part, 17b ... Vertical wall Part, 18 ... Secondary air hole, 19 ... Gap, 20 (20a) ... Heat shield, 21 ... Step, 22 ... Cooling gap, 23 ... Through hole.

Claims (1)

[Claims] 1. A two-sided combustion chamber wall having a large number of flame openings is opposed to form a combustion chamber, a secondary air chamber is formed outside the combustion chamber, and an upper end of the combustion chamber wall is formed. An outward facing flange portion is provided, and a cover having an outward facing inclined wall portion having a large number of secondary air holes formed above the flange portion and a vertical wall portion connected to the outward inclined wall portion is provided. The vertical wall portion is arranged outside the combustion chamber wall, and a gap communicating with the secondary air chamber is provided between the lower end of the vertical wall portion of the cover and the flange portion, and the upper end of the combustion chamber wall is provided. A heat shield plate is provided on the upper surface of the flange part of the cover to cover the vertical wall part of the cover with a cooling gap between the cover and the vertical wall part. The heat shield plate forms a step on the upper part of the combustion chamber wall. It is located outside the wall and has many through holes to supply secondary air to the upper part of the combustion chamber together with the secondary air holes. Combustion apparatus to so that.