JP3066792B2 - Hot air heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion chamber having a built-in burner and a blower fan provided inside a housing, and the blower fan sucks and exhausts combustion gas from the combustion housing and sucks air from the outside to burn the combustion chamber. The present invention relates to a hot air heater that mixes gas and air and blows the hot air outside the device.

[0002]

2. Description of the Related Art Conventionally, as a warm air heater of this type, a combustion cover extending upward and surrounding a flame of a burner is provided in a vertically long combustion casing, and a flow direction of the flame, that is, a vertical direction, is provided in the combustion cover. Along with providing a plurality of throttle members at intervals in the direction, the combustion cover is provided with air holes facing each of a plurality of combustion regions in the combustion cover defined by the throttle members, and is introduced into the combustion housing. It is known that air is supplied to each combustion zone through these air holes to perform multi-stage combustion (see JP-A-61-213412).

[0003]

When the multistage combustion is performed as in the above-described conventional example, the combustion reaction becomes slow, the increase in the flame temperature is suppressed, and the concentration of nitrogen oxide (NOx) is reduced. When the high-temperature combustion gas is rapidly cooled, nitrogen monoxide (NO), which is a main component of NOx, is converted into nitrogen dioxide (N
O ₂ ), but when multi-stage combustion is performed, the combustion gas generated by the combustion reaction in the upstream combustion region is gradually cooled by air from the air holes in the downstream combustion region,
NO ₂ concentration decreases.

[0004] NO ₂ is particularly harmful among the NOx, in order to reduce the NO ₂ concentration, the number of combustion zone in the combustion cover, i.e., it is desired to increase the combustion stages,
Increasing the number of stages increases the height of the combustion cover, and hence the size of the combustion case that houses the combustion cover, and increases the size of the heater. In view of the above, an object of the present invention is to make it possible to increase the number of combustion stages without increasing the size of a heater.

[0005]

Means for Solving the Problems In order to solve the above problems,
According to the present invention, a combustion case having a built-in burner and a blower fan are provided in the case body, and the combustion gas is sucked and exhausted from the combustion case by the blower fan and air is sucked from the outside of the case, thereby mixing the combustion gas and air. A warm air heater that blows out hot air outside the vessel, and a combustion cover surrounding the flame of the burner is provided in the combustion housing, and a plurality of throttle members are provided inside the combustion cover at intervals in the flow direction of the flame. At the same time, the combustion cover is provided with air holes facing each of a plurality of combustion areas in the combustion cover defined by these throttle members, and the air introduced into the combustion housing is supplied to each combustion area through these air holes. In the multistage combustion, the combustion case is formed to have a rising portion, a substantially inverted U-shaped curved portion at the upper end of the rising portion, and an outlet portion extending below the curved portion, and the combustion case is formed. A burner is arranged at the bottom of the rising section. At the same time, the combustion cover extends from the rising portion of the combustion case to the curved portion, and a plurality of combustion areas defined by the throttle member are provided in the curved portion of the combustion cover located at the curved portion of the combustion case. .

[0006] By curving the upper end of the combustion cover in this way, the number of combustion areas can be increased without increasing the height dimension, and N-stage combustion can be performed by multi-stage combustion without increasing the size of the heater.
O ₂ concentration can be reduced.

When the curved portion is formed in the combustion cover, the pressure loss at the curved portion increases, and it is necessary to increase the rotation speed of the blower fan in order to prevent insufficient suction of the combustion gas. become. However, when the rotation speed of the blower fan is increased, the fan motor noise and the wind noise increase, and the noise becomes a problem. In this case, if the passage area between the combustion regions narrowed by the throttle member is made larger at the curved portion of the combustion cover than at the rising portion of the combustion cover located at the rising portion of the combustion case, the pressure loss at the curved portion is reduced. Further, the combustion gas can be sufficiently sucked without increasing the rotation speed of the blower fan, which is advantageous.

Further, in the curved portion, the combustion gas tends to come into contact with a cover wall on the outer diameter side of the curved portion due to an upward flow velocity vector due to inertia.
O is easily converted to NO ₂ . In this case, if the throttle member provided on the outer diameter side of the curved portion of the combustion cover is inclined to the downstream side, the throttle member functions as a rectifying plate that changes the flow direction of the combustion gas, and the combustion gas flows inside the curved portion. It flows smoothly without drifting to the outer diameter side, the contact of the combustion gas with the outer diameter side cover wall is suppressed, and the conversion of NO to NO ₂ is suppressed.

When the combustion gas from the combustion cover is directly discharged toward the outlet of the combustion case, a large amount of air is suddenly mixed with the combustion gas, the combustion gas is rapidly cooled, and NO is reduced to N.
Converted to O ₂ . In this case, a duct extending downward in the outlet portion of the combustion case is connected to the end of the curved portion of the combustion cover, and an opening is formed in the duct over a predetermined range in the vertical direction. air is gradually mixed from, the combustion gas is to be slowly cooled in the duct, and the conversion of NO to NO ₂ is suppressed at the outlet portion of the combustion housing, NO ₂ concentration is further reduced .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, reference numeral 1 denotes a body of a hot air heater, in which a combustion casing 2, a blower fan 3 below the casing, and a combustion casing 2 are provided. And a partition wall 4 surrounding a portion where the blower fan 3 is disposed. An air passage 11 is defined inside the partition wall 4 and communicates with an intake port 10 opened on the back of the body 1, and the blower fan 3 sucks and exhausts combustion gas from the combustion housing 2, and also connects the air passage 11 to the air passage 11. Air is sucked from the outside of the device via the air, the combustion gas and the air are mixed, and the air is blown out of the device as warm air from the blower port 12 at the lower front surface of the device body 1.

A control device (not shown) is accommodated in a space 13 outside the partition wall 4.
a is opened, and a part of the air from the intake port 10 is
Then, the air is sucked into the blower fan 3 from the window hole 4a and the control device is air-cooled. In FIG. 1, the flow of air is indicated by a white arrow, the flow of combustion gas is indicated by a black arrow, and the flow of warm air in which air and combustion gas are mixed is painted in white and black. Indicated by an arrow.

The combustion case 2 includes a rising portion 20, a substantially inverted U-shaped curved portion 21 at the upper end thereof, and an outlet portion 22 extending downward from the curved portion 21 and in front of the rising portion 20.
In the combustion case 2, a burner 5 is provided at a lower portion of the rising portion 20, and the burner 5 is provided from the rising portion 20 to the bending portion 21.
The combustion cover 6 surrounding the flame of the burner 5 is provided with a ventilation gap 23 around it. As shown in FIG. 2, the burner 5 and the combustion cover 6 are inserted into the combustion case 2 through a mounting hole 24 formed on one lateral side of the combustion case 2. . In the figure, reference numeral 26 denotes an outer plate of the combustion housing 2 which constitutes the curved portion 21 and the outlet portion 22.

[0013] the combustion cover 6, a plurality of a plurality of diaphragm member 60 provided at intervals in the flow direction of the flame, for example, six combustion region 61 _1, 61 ₂ are partitioned into ... 61 _6, most upstream, i.e., burners 5 at the lower end of the combustion region 61 ₁ the lowermost is fitted in the flange 50 of the upper end. The flange 50, a small air hole 51 for taking the combustion secondary air enough to cause oxygen deficiency combustion are opened, and each combustion in the combustion cover 6 regions 61 _1-6
Facing the 1 _6, the air hole 62 of approximately the same size air holes 51
It was established by supplying air through the vent clearance 23 from the air holes 51 and 62 into the combustion area 61 _{1-61 6} from the intake port 10, so that to perform a multi-stage combustion.

[0014] While the passage area between the combustion region 61 _{1-61 6} is throttled by the throttle member 60, the curved portion 2 of the combustion housing 2
Combustion area 6 in the curved portion of the combustion cover 6 located at 1
Passage area between 1 _4, 61 _5, 61 _6, is formed larger than the passage area between the combustion region 61 _1, 61 _2, 61 ₃ in the rising portion of the combustion cover 6 positioned upright portion 20 of the combustion housing 2 ing. Thus, an increase in the exhaust resistance in the curved portion of the combustion cover 6 is suppressed, and insufficient suction of the combustion gas does not occur without increasing the rotation speed of the blower fan 3. But the illustrated combustion a passage width L1 between the combustion region 61 _1, 61 ₂ region 6
1 _2, 61 ₃ the passage width L2 respectively between 16 mm, the combustion region 6
1 _3, 61 ₄ between the passage width L3 and the combustion region 61 _4, 61 ₅ between the passage width L4 between the combustion region 61 ₆ outlet passage width L6 and respectively 21 mm, combustion zone 61 _5, 61 between ₅ aisle widths L5 24
mm.

A throttle member 60, indicated by A and B in the figure, which is provided on the outer diameter side of the curved portion of the combustion cover 6 is inclined downstream so that the flame or the combustion gas flows upward due to inertia. It is prevented from hitting the outer diameter side cover wall of the curved portion. An auxiliary throttle member 60 'is provided between the A and B throttle members 60, and the auxiliary throttle member 60' is provided.
From the auxiliary air hole 62 ′ opened downstream of the combustion zone 6.
The air is taken into ₁₅ . In the curved portion, the projecting distance of the diaphragm member 60 provided on the outer diameter side from the outer diameter side cover wall is made larger than the projecting distance of the diaphragm member 60 provided on the inner diameter side from the inner diameter side cover wall. The effect of preventing the combustion gas from coming into contact with the side cover wall can be further enhanced.

At the tip of the curved portion of the combustion cover 6, a duct 63 extending downward in the outlet portion 22 of the combustion case 2 is provided in a row, and as shown in FIG. A slit-shaped opening 63a is formed over the range. Here, the combustion reaction is adapted to complete up to the combustion region 61 _6, the duct 63 flows combustion gas containing no unburned gas. In this case, if there is no duct 63, a large amount of air is suddenly mixed with the combustion gas, and the combustion gas is rapidly cooled. When such rapid cooling occurs, nitrogen monoxide (N) which is a main component of nitrogen oxides (NOx) in the combustion gas
O) is converted to nitrogen dioxide (NO ₂ ). However, if the duct 63 is provided as in the present embodiment, the air from the opening 63a is gradually mixed with the combustion gas, the combustion gas is gradually cooled, and the conversion rate from NO to NO ₂ is increased. Becomes lower. The opening 63a may be formed by arranging small holes.

Next, test results will be described. The test was the same as that of the above embodiment (hereinafter referred to as product 1) and the product 1 had the same basic configuration, and provided throttle members corresponding to the throttle members A and B at right angles to the flame flow direction. (Hereinafter referred to as product 2) and a two-stage combustion type having a combustion cover having only two combustion regions corresponding to the combustion regions 61 ₁ and 612 of products ₁ and ₂ (hereinafter referred to as product 3). ), The input to the burner 5 was set to 3000 kcal, and the NOx concentration and the NO ₂ concentration in the warm air blown out from the blower opening 12 were measured. The rotation speed of the blower fan 3 was set to 800 rpm.

The results are as shown in the table below.
Conversion to ₂ (NO ₂ / NOx) is the product 3 34.9
%, 15.8% for product 2 and 9.1% for product 1.

[0019] As is clear from this table, the products 1 and 2 are NOx more than the two-stage combustion type product 3 in spite of the six-stage combustion type.
Although the concentration increases, the NO ₂ concentration is lower in the products 1 and 2 than in the product 3. The NOx concentration of the products 1 and 2 is high because the curved combustion cover 6 increases the ventilation resistance and slows the flow rate, and reduces the amount of secondary air sucked from the air holes 62 to reduce the cover 6. It is considered that the combustion time in the inside becomes long, the combustion flame becomes long, and the NO generation region becomes wide. Further, the low NO ₂ concentration of the products 1 and ₂ is because the combustion gas generated in each combustion region is gradually cooled by the mixing of air from the air holes 62 and 62 ′ in the downstream combustion region. It is considered that the cooling is gradually performed by mixing the air from the opening 63a in the inside.

Further, the the NO ₂ concentration towards than Product 2 Product 1 is lowered, the contact of the combustion gases due to the upward inertial force to the outer diameter side cover wall of the combustion cover 6 in the combustion area 61 _5, 61 ₆ Is suppressed by the inclination of the throttle members 60 for A and B of the product 1, and NO due to cooling of the combustion gas at the cover wall is reduced.
It is considered that the conversion from NO to NO ₂ is suppressed.

Although the embodiment of the six-stage combustion type has been described above, the present invention is not limited to the six-stage combustion type.

[Brief description of the drawings]

FIG. 1 is a cutaway side view of an example of the heater of the present invention.

FIG. 2 is an exploded perspective view showing the structure of a combustion case.

[Explanation of symbols]

1 instrument body 2 combustion housing 20 rising portion 21 curved portion 22 outlet 3 blower fan 5 burner 6 combustion cover 60 throttle member 61 _{1-61 6} combustion zone 62 the air hole 63 duct 63a opening

Continued on the front page (72) Inventor Kazuji Sugimoto 2-26, Fukuzumi-cho, Nakagawa-ku, Nagoya-shi, Aichi Rinnai Co., Ltd. (72) Inventor Tsutomu Sobue 2-26, Fukuzumi-cho, Nakagawa-ku, Nagoya-shi, Aichi Rinnai stock In-house (56) References JP-A-62-172931 (JP, U) JP-A-61-101359 (JP, U) JP-A 58-185728 (JP, U) JP-A 6-6906 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F24H 3/04 301

Claims (4)

(57) [Claims] 1. A combustion housing having a built-in burner and a blower fan are provided in a housing, and a combustion fan sucks and exhausts combustion gas from the combustion housing and sucks air from outside the housing to mix the combustion gas and air. A hot air heater that blows out hot air outside the vessel, and a combustion cover surrounding a flame of a burner is provided in a combustion housing, and a plurality of throttle members are provided in the combustion cover at intervals in a flow direction of the flame. Along with providing a combustion cover, air holes facing each of a plurality of combustion areas in the combustion cover defined by these throttle members are opened, and air introduced into the combustion housing is passed through these air holes to each combustion area. In the supply and multi-stage combustion, the combustion case is formed to have a rising portion, a substantially inverted U-shaped curved portion at an upper end of the rising portion, and an outlet portion extending below the curved portion. Burner at the bottom of the riser Disposing, extending the combustion cover from the rising portion of the combustion case to the curved portion, providing a plurality of combustion areas defined by the throttle member also in the curved portion of the combustion cover located at the curved portion of the combustion case; A hot air heater characterized by the following. 2. The combustion chamber according to claim 1, wherein a passage area between the combustion areas narrowed by the throttle member is larger at a curved portion of the combustion cover than at a rising portion of the combustion cover located at a rising portion of the combustion case. A warm air heater according to claim 1. 3. The throttle member provided on the outer diameter side of the curved portion of the combustion cover is inclined to the downstream side.
Or the warm air heater according to 2. 4. A duct extending downward from the end of the combustion housing at the tip of the curved portion of the combustion cover, and an opening is formed in the duct in a predetermined range in the vertical direction. The hot air heater according to any one of claims 1 to 3.