JPH0656248B2 - Hot air heater - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hot air heater that achieves low NO _X combustion by two-stage combustion.

2. Description of the Related Art Conventionally, a hot air heater related to low NO _X combustion of this type is
As shown in the figure, a rectangular first box body 2 having a single rectangular secondary flame hole 1 formed on the upper surface surrounds the primary flame hole 4 of the Bunsen burner 3 and It consisted of a Bunsen burner 3 and a second box 5 that surrounds the first box 2 and forms a hot air passage.

Problems to be Solved by the Invention However, with the above configuration, although the NO reduction can be sufficiently achieved, there are the following problems.

(1) Since the secondary air is slowly supplied to the secondary flame hole 1 and the secondary flame B extends, it is difficult to design the body so as not to contact the secondary flame hole B. As a heater, downsizing was a problem.

(2) The primary flame hole 4 and the first box body 2 are fitted together,
Moreover, since the fitting portion is repeatedly used between room temperature and high temperature, squeaking noise or the like is generated.

Means for Solving the Problems In order to solve the above problems, the hot air heater according to the present invention is
A premixed combustion burner having a secondary flame hole and the premixed combustion burner are housed, and except for a single rectangular secondary flame hole formed on the upper surface, they are shielded from the atmosphere and are located below the secondary flame hole. The first box body having a rectangular parallelepiped shape, which is provided with protrusions facing inward over the entire length in the longitudinal direction of both side surfaces, and the first box body, and has openings at both ends of the upper surface and the lower surface. ,
At a position above the secondary flame hole, there is provided a second box body in which protrusions are formed inwardly over the entire length in the longitudinal direction of both side surfaces.

Operation The present invention has a premixed combustion burner having the structure described above.
Since it is completely surrounded by the first box body having the secondary flame hole, there is no fitting portion and squeaking noise is unlikely to occur. Further, since the secondary air does not flow into the box body from the fitting portion, it does not flow into the primary flame holes and diffusely mixes with the unburned gas on the secondary flame holes. Therefore, the primary flame is formed on the primary flame and the secondary flame is formed on the secondary flame. Moreover, the secondary air flows in the direction of the central axis of the second box body due to the protrusion of the second box body, so that the secondary air is rapidly mixed with the hot end-burning gas, and as a result, the secondary flame is shortened and stable. The two-stage combustion can be performed. Further, the projection of the first box is provided below the secondary flame hole, but this can be a flame hole for the secondary flame when the combustion amount is reduced, and the projection is a flame. By forming the holes, it is shown that the space between the primary flame hole and the protrusion, that is, the volume of the combustion chamber can be changed according to the combustion amount.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings. At the first time, the premixed combustion burner 11 is surrounded by a rectangular box-shaped first box body 12. Same box 12
Is provided with a single secondary flame hole 13 in a rectangular shape, and both side surfaces in the longitudinal direction are located above the primary flame hole 14 of the premixed combustion burner 11 over the entire side surface length. Protrusions 15 are provided toward the inside of the box body 12. Since the second box body 16 constitutes a warm air passage, an air intake and a warm air outlet are provided in each part. Further, in the second box body 16, at a position above the secondary flame hole 13, over the entire length in the longitudinal direction of both side surfaces, a protrusion 17 is formed toward the inside.
Is provided. The blower 18 is provided below the second box body 16, and each box body and the blower 18 are surrounded by a body 19.

In the above configuration, since the secondary air does not flow into the first box body 12, the primary flame C corresponding to the primary air amount of the premix combustion burner 11 is formed on the primary flame hole 14, The high temperature unburned gas, which could not be completely burned by the primary air amount, is collected on the secondary flame hole 13 by the first box body 12 and the second box body 1.
The secondary air that has passed through the gap 6 is mixed and diffused to form the secondary flame D. By such a complete two-stage combustion, it is possible to further reduce the NO _x . At this time, the first box 1
The second protrusion 17 contributes to the stabilization of the flame when the combustion amount is reduced by the process described below. When the combustion amount starts to be reduced, the above-mentioned high temperature unburned gas amount gradually decreases and becomes 2
The external flame D can no longer be formed on the secondary flame hole 14. This is because the flame holding property is deteriorated due to the temperature drop at the edge of the secondary flame hole 13 by reducing the combustion amount, and the unburned gas is insufficient. If no flame is formed on the secondary flame holes 13, the secondary air that could not enter the first box body 12 until then has no resistance and is easy to flow in. On the other hand, the protrusion 15 of the first box 12 is kept in a high temperature state due to heat transfer from the primary flame C and unburned gas. These conditions are
The secondary flame D is formed on the protrusion 15 from the unburned gas and the secondary air flowing into the first box 12. Further, when the combustion amount is reduced and the secondary flame D is not formed even on the protrusion 15, the secondary air diffuses to the vicinity of the primary flame hole 14. In this state, the two-stage combustion is no longer maintained, but a premixed flame is formed on the primary flame holes 14. As described above, according to the protrusion 15 of the first box body 12, even if the combustion amount is changed, it is possible to maintain a stable flame that matches the condition. Further, since the protrusion 17 of the second box body 16 changes the flow of the secondary air in the central axis direction of the box body 16,
The high-temperature unburned gas flowing vertically upward collides with the high-temperature unburned gas at a certain angle, and the diffusion-mixing process between the two is performed more rapidly than when the two diffuse-mix in parallel. It will be. As a result, the secondary flame D formed on the secondary flame hole 13 is shortened and the unburned gas and the secondary air are diffused first regardless of the increase and decrease of the primary and secondary air amounts. It is stably formed on the secondary flame hole 13 to be mixed, and the secondary flame D is never formed on the protrusion 17 of the second box body 16.
Is not formed.

Effects of the Invention As described above, according to the combustion device of the present invention, the following effects are obtained.

I. By rapidly diffusing and mixing the high temperature unburned gas and the secondary air, the secondary flame can be shortened. As a result, the instability phenomenon of the secondary flame due to lack of primary air due to oxygen deficiency / damper clogging etc. It can be suppressed, and good combustion sustainability can always be ensured.

In addition, the compactness of the device can be realized by shortening the secondary flame.

II. Since the supply of the secondary air can be reliably delayed, reliable two-stage combustion can be realized, and the NO _x can be further reduced.

III. Since the load of the combustion chamber according to the combustion amount can be obtained by the protrusion of the first box body, the narrowing width of the combustion amount can be expanded.

IV. Since the premixed combustion burner and the first box surrounding the premixed combustion burner are not fitted together, squeaking noise due to the heat cycle is less likely to occur.

[Brief description of drawings]

FIG. 1 is a side sectional view of a warm air heater showing an embodiment of the present invention, and FIG. 2 is a side sectional view of a conventional warm air heater. 11 ... Premixed combustion burner, 12 ... First box, 13
…… Secondary flame hole, 15 …… Projection of the first box, 16 ……
Second box, 17 ... Projection of the second box, 18 ... Blower, 19 ... Body.

Claims (1)

[Claims] 1. A premixed combustion burner having a primary flame hole and the premixed combustion burner are housed, and the secondary flame burner except the single rectangular secondary flame hole formed on the upper surface is isolated from the atmosphere. A rectangular parallelepiped first box body provided with protrusions inwardly over the entire length in the longitudinal direction of both side surfaces at positions lower than the flame holes,
It surrounds the first box, has openings at both ends of the upper surface and the lower surface, and is located above the secondary flame hole, over the entire length in the longitudinal direction of both side surfaces, and projecting toward the inside. A warm air heater comprising a second box body that forms a box, a blower provided in the warm air passage, and a body that surrounds each box body and the blower.