JPH07260108A - Burner device - Google Patents

Abstract

PURPOSE:To permit low NOx combustion by a method wherein a combustion chamber is opened to provide a secondary flame port for high combustion while an auxiliary combustion chamber, covering a primary flame port so as to be capable of transferring heat, is provided in the combustion chamber and the auxiliary combustion chamber is provided with an auxiliary combustion chamber frame port for weak combustion. CONSTITUTION:A combustion chamber 4 is provided in a space upper than a primary flame port 2 for a burner 1 receiving a burner while the upper surface of the combustion chamber 4 is opened to make it a secondary flame port 20 upon high combustion. An auxiliary combustion chamber 3, equipped with an auxiliary combustion chamber flame port 5 at the upper surface thereof, is constituted so as to cover the vicinity section 29 of the primary flame port 2 of the burner 1. The fixed auxiliary combustion chamber 3 is heated by the radiation heat of the primary flame 19 whereby an auxiliary combustion chamber fixing section 28 is heated by the transfer of heat and the temperature of the same is risen. The vicinity section 29 of the primary flame port 2 is heated directly by the primary flame 19 while heating of the vicinity section 29 is transferred to the whole of the burner 1 in addition to the heat transfer of the auxiliary combustion chamber fixing section 28 and the temperature of the whole of the burner 1 is increased whereby fuel gas in the burner 1 is heated and expanded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for reducing NOx suitable for household combustion equipment.

[0002]

2. Description of the Related Art Conventionally, an apparatus of this type has been disclosed in FIG.
As in Japanese Patent Laid-Open No. 2-39329, the Bunsen burner 11 has a primary flame hole 12 that partially opens on the upper surface and is covered with a primary combustion chamber wall 13 having a secondary flame hole 14. With this configuration, the flame at the time of maximum combustion is the primary flame hole 12
A primary flame 15 is formed on the upper side, and a secondary flame 16 is formed on the secondary flame hole 14. Further, at the time of minimum combustion, the primary flame 1 on the primary flame hole 12
The secondary flame 16 could not be formed in the secondary flame hole 14 immediately outside of No. 5, and the secondary flame 16a was formed immediately outside of the primary flame 15 in the wall of the primary combustion chamber.

[0003]

However, in this kind of two-stage combustion, the primary flame hole 12 and the secondary flame hole 1 are usually used.
The load of 4 is designed with a value suitable for the maximum combustion amount. For this reason, at maximum combustion, a perfect 2 due to flame holding in each flame hole 12,14.
Stage combustion can be formed. On the other hand, if the combustion amount is reduced, the secondary flame hole 1
Since the load on 4 is too low, the secondary flame 16 is less likely to be formed on the secondary flame hole 14 and the two-stage combustion does not occur, and the secondary flame 16a is formed on the primary flame hole 12 outside the primary flame 15. It becomes a normal premixed flame that can be integrated, and the NOx concentration in the combustion exhaust gas increases. That is, when the amount of combustion is reduced, there is a problem that two-stage combustion is not performed and low NOx combustion cannot be realized. Further, there is a problem that the primary flame is easily lifted under the condition that the oxygen concentration in the atmosphere is lowered.

[0004]

In order to solve the above-mentioned problems, the burner device of the present invention is provided with a Bunsen burner having a primary flame hole on the upper surface thereof, and the Bunsen burner is accommodated in the space on the primary flame hole side of the Bunsen burner. As a combustion chamber, the combustion chamber is opened to have a secondary flame hole for high combustion, and an auxiliary combustion chamber is provided in the combustion chamber to cover the primary flame hole of the Bunsen burner so that heat can be transferred. The chamber is provided with an auxiliary combustion chamber flame hole for weak combustion that is open.

For the flame in the combustion chamber, an auxiliary air hole communicating with the outside air is provided on the wall of the combustion chamber.

[0006]

With the above-described structure, in the present invention (1), when the amount of combustion is large, the secondary flame is formed on the secondary flame hole to form the two-stage combustion. Further, when the amount of combustion is small, the secondary flame is formed on the auxiliary combustion chamber flame hole, and even if the position of the secondary flame is changed, the secondary combustion still occurs. The primary flame of the auxiliary combustion chamber raises the primary flame temperature by heat reflection from the auxiliary combustion chamber wall, and stable two-stage combustion can be realized.
Ox combustion becomes possible. Further, by contacting the auxiliary combustion chamber fixing portion of the auxiliary combustion chamber in the vicinity of the primary flame hole, the burner body is heated, the fuel gas in the burner body expands, and the gas ejection speed from the primary flame hole increases. As for the primary air area, the degree of suction increases due to an increase in the gas ejection speed from the primary flame hole, so the primary air area can be reduced, and excess air during high combustion can be suppressed to further improve combustion performance.

In the second means, the primary flame easily lifts irrespective of the combustion amount in the low oxygen concentration state and when the primary air amount is insufficient. Therefore, the auxiliary air hole communicating with the outside air is formed in the combustion chamber wall. By providing the above, combustion air can be taken in from the auxiliary air holes to stabilize the primary flame when the oxygen concentration is low and the primary air amount is insufficient.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a hot air heater according to an embodiment used in the present invention. In FIG. 1, reference numeral 1 is a burner body, which has two primary flame holes. The primary flame holes 2 are also provided on the upper surface or the side surface of the burner 1, and the shape of the primary flame holes may be elongated slits or round holes. Alternatively, the opening of the primary flame hole 2 may be covered with a wire mesh. Reference numeral 3 denotes an auxiliary combustion chamber, which houses the upper portion of the burner 1. The combustion chamber 4 is covered with a combustion guide A6, a combustion guide B7, and a combustion guide C8. During combustion, the blades 10 are rotated by driving the motor, and the warm air heated by the burner 1 flows along the blade guides 17. The hot air heated by the burner 1 is the blade 1
Aspirated by 0. The air required to burn the burner 1 is
Combustion air passes through a gap on the right side of the combustion guide B7 and the combustion guide C8 and becomes combustion air. Further, the air passing between the combustion guide C8 and the combustion guide A6 is mixed with the hot air heated by the burner 1 to become warm air, and flows along the blade guide 17 by the suction force of the blade 10. The combustion guide D18 is a guide for a passage of hot air heated by the burner 1. The combustion chamber unit 24 is covered with an outer box 25, and the vane guide 1
The warm air that has flowed along 7 is blown out from a warm air outlet 26 provided in the outer box 25.

Next, the structures of the combustion chamber 4, the auxiliary combustion chamber 3 and the burner 1 will be described with reference to FIGS. 2 and 3. 2,
In FIG. 3, the auxiliary combustion chamber 3 has an auxiliary combustion chamber flame hole 5 on the upper surface.
The burner 1 is configured so as to cover a portion 29 (a portion surrounded by a broken line) near the primary flame hole 2 of the burner 1. The auxiliary combustion chamber fixing portion 28 below the auxiliary combustion chamber 3 is tightly fixed to a portion 29 near the primary flame hole 2 of the burner 1 so as not to cover the primary flame hole 2. Since the fixed auxiliary combustion chamber 3 is heated by the radiant heat of the primary flame 19, the auxiliary combustion chamber fixing portion 28 is also heated and heated by heat conduction. The vicinity 29 of the primary flame hole 2
Is also directly heated by the primary flame 19, the heat of the auxiliary combustion chamber fixing portion 28 is added to the heat of the neighboring portion 29 and the heat is transferred to the entire burner 1, and the temperature of the entire burner 1 rises. The fuel gas inside is heated and expanded. When the fuel gas in the burner 1 expands and the specific gravity becomes lighter, the difference in specific gravity from the outside air increases and the gas ejection speed from the primary flame hole 2 increases. From the burner inlet 30 due to the increase in gas ejection speed. The intake amount of primary air increases. That is, the draft as a force for ejecting the fuel gas from the primary flame hole 2 becomes large, and the suction amount of the primary air from the burner inlet 30 is larger than that when the auxiliary combustion chamber 3 is not attached.
Since the primary flame 19 is formed in the entire combustion range, this draft increase can be expected in all combustion states. Therefore, the adjustment of the intake air amount by the damper or the like at the burner inlet 30 requires tightening. By the way, since the ratio of the air intake amount inevitably increases at low combustion compared to that at high combustion, a design consideration that slightly reduces the excess air ratio at high combustion is sufficient to maintain an excessive air condition at low combustion. It was covered, if not said. However, if the auxiliary combustion chamber 3 is attached, the above-mentioned draft can be expected to increase, and an extra amount for improving low combustion performance during high combustion,
The excess air ratio, which must be intentionally reduced in combustion performance, is reduced, and better high combustion performance can be obtained.

Furthermore, the addition of the auxiliary combustion chamber 3 can also improve the intermediate combustion performance. That is, the auxiliary combustion chamber 3 receives the primary flame 19 during all intermediate combustions during the high combustion.
Radiation heats the auxiliary combustion chamber 3 to store heat. The stored auxiliary combustion chamber 3 heats the burner 1 via the auxiliary combustion chamber fixing portion 28, and reflects a part of radiant heat to raise the temperature of the primary flame 19. In other words, the flame temperature of the primary flame 19 rises and the supplementary flame performance as the flame forming performance is strengthened, the combustion performance of the primary flame 19 is improved, and the combustion performance after the completion of the secondary flame 12 can be enhanced.

Next, the auxiliary combustion chamber flame hole load (auxiliary combustion chamber 3
The ratio of the amount of combustion in the flame hole area 22) is smaller than the primary flame hole load of the primary flame hole 2, and the secondary flame hole load of the secondary flame hole 20 (the combustion amount of combustion in the secondary flame hole 22) (Comparison of flame area 23)
Is equal to or larger than the auxiliary flame hole load 22. Height position L of auxiliary combustion chamber 3 provided in combustion chamber 4
1 is set according to the combustion range of the maximum burner amount and the minimum burner amount of the burner 1. When the combustion amount in the burner device configured as described above is large, the primary flame 19 is formed on the primary flame hole 2 and the secondary flame 12 is formed on the secondary flame hole 20 to achieve complete two-stage separation. It becomes a flame. When the amount of combustion is small, the primary flame 19 is on the primary flame hole 2 and the secondary flame 12
The a is formed on the flame hole 5 of the auxiliary combustion chamber, and here again, it is a complete two-stage separation flame. Therefore, a complete two-stage separation flame can be realized over the entire combustion amount, and stable low NOx combustion can always be realized. On the other hand, under the condition that the primary air is insufficient or the oxygen concentration in the atmosphere is reduced, the primary flame 19 is likely to lift. In fact, when the air inlet 31 with a filter provided at the rear of the exterior box 25 becomes clogged with dust for a long time, the amount of air taken in by the fan 10 decreases and the air can be sucked from the burner inlet 30 into the burner 1 for combustion. The amount of primary air also decreases. When the primary air deficiency occurs in this way, the unburned mixed gas that has reached the secondary flame hole 20 due to lack of oxygen for combustion scatters from the secondary flame hole 20 to the surroundings for combustion air and burns quickly. Try to complete. This phenomenon is completely opposite to the so-called "flame-removing effect" in which sufficient oxygen can be supplied for combustion, and therefore the lift phenomenon occurs. In addition, in a use example in which oxygen is not supplied due to turbulence with fresh air due to long-time combustion in a closed room, the oxygen content in the air is inevitably lowered, that is, the oxygen concentration is lowered. At this time as well, similar to the lack of primary air described above, the combustion tends to lift, and CO gas and NO
The generation rate of harmful gas such as x increases. In this case,
Since the auxiliary air hole 27 of the combustion chamber 4 communicates with the outside air, the combustion air can be introduced even if the combustion of the primary flame 19 is destabilized. The auxiliary air hole 27 normally supplies a small amount of primary air to the secondary flame 12 and the secondary flame 12a.
Has a slight secondary air supply effect on. In the case where the oxygen supply amount is insufficient as described above, the degree of deterioration of the combustion performance can be mitigated until it acts as an emergency air supply hole and reaches a certain low oxygen concentration. In other words, it works to the extent that it is not necessary to expect the action under normal conditions, but it can be done with an opening area that can be expected when the oxygen concentration is low. May be.

[0012]

As described above, according to the burner device of the present invention, the following effects can be obtained. (1) In claim 1, the burner main body is covered with a box body having secondary flame holes, and the primary flame holes of the burner body are also covered with an auxiliary combustion chamber having auxiliary flame holes so that heat can be transferred. Since the auxiliary combustion chamber flame holes in the chamber enhance the flame holding property of the primary flame on the primary flame holes, CO in the exhaust gas can be lowered and stable two-stage combustion can be realized over the entire combustion range. In addition, the temperature of the burner body rises due to heat transfer from the auxiliary combustion chamber, etc., and the temperature of the gas inside the burner body rises, and the gas ejection speed increases, so the primary air area can be reduced, and the excess on the high combustion side A low NOx combustion becomes possible by suppressing the air ratio. (2) According to claim 2, the auxiliary air hole is provided in the wall of the combustion chamber communicating with the outside air, so that the auxiliary air for combustion is introduced when the primary air is insufficient or when the oxygen concentration in the atmosphere decreases. It is possible to stabilize the flame.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a hot air heater incorporating a burner device according to an embodiment of the present invention.

FIG. 2 (a) Side view and sectional view of the same device (b) A-A line sectional view in the above (a) sectional view of the same device

FIG. 3 is a cross-sectional view showing a state of the device during combustion.

FIG. 4 is a sectional view of a conventional burner device.

[Explanation of symbols] 1 burner body 2 primary flame hole 3 auxiliary combustion chamber 4 combustion chamber 5 auxiliary combustion chamber flame hole 12 secondary flame 19 primary flame 20 secondary flame hole 27 auxiliary air hole

Claims (2)

[Claims] 1. A Bunsen burner having a primary flame hole, a combustion chamber accommodating the Bunsen burner and provided on the side of the primary flame hole, and a secondary flame for high combustion in which a part of the combustion chamber is opened. A burner device comprising: a hole, an auxiliary combustion chamber provided in the combustion chamber to cover the primary flame hole of the Bunsen burner, and an auxiliary combustion chamber flame hole for weak combustion, which opens a part of the auxiliary combustion chamber. 2. The burner device according to claim 1, wherein an auxiliary air hole communicating with outside air is provided on a side wall of the combustion chamber.