JPS61291803A - Combustion device - Google Patents

Abstract

PURPOSE:To reduce NOx content by a method wherein a cooling pipe is passed through a primary combustion chamber and a primary flame is directly cooled. CONSTITUTION:A cooling pipe 11 passing through a primary combustion chamber 2 and also through a secondary combustion chamber 3 and a guide plate 10 is provided over a burner 1 and both ends of the cooling pipe are opened as a cooling air inlet port 12 and a cooling air outlet 13. The air sucked from the cooling air inlet port 12 under operation of a hot-air fan 14 removes heat from the primary flame within the cooling pipe 11, is flowed into the hot-air passage from the cooling air outlet 13, mixed with the ignited gas and blown from the hot-air blowing port 16 as the hot air. As a result of decreasing in temperature of the primary flame, it is possible to reduce a production volume of NOx.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a combustion device that can be used as a heating device, a heating device, etc.
y, = combustion equipment.

Prior Art Conventional devices of this type include the following. That is, as shown in FIGS. 2 and 3, a burner 1 and a primary combustion chamber 2 provided above the burner 1 are provided in a secondary combustion chamber 3, and the burner 1 is connected to a mixture chamber 5 and a flame. The flame hole part 6 has a large number of flame holes 8 opening in the vertical direction, and the air-fuel mixture with an air ratio of about 0.6 to 0.9 is supplied through the air-mixture chamber 5. The flame is ejected from this flame hole 8 to form a primary flame.

However, although first-stage combustion is performed in the primary combustion chamber 2, unburned gas containing C6F6 as a main component is generated due to incomplete combustion due to lack of air. This unburnt gas is provided in the upper part of the primary combustion chamber and forms a secondary flame with secondary air supplied from the gap 4 in the secondary flame hole section 7, and a second stage of combustion is performed. There is something to complete. (For example, Japanese Patent Publication No. 56-32524) Problems to be Solved by the Invention However, the above configuration has the following drawbacks.

In other words, in the two-stage combustion method, combustion is performed in the primary combustion chamber in an oxygen-deficient state (in other words, in a state of excess fuel with an air ratio of 1 or less), suppressing the formation of NOx due to oxidation of N, and suppressing the generation of this insect-killing combustion gas. By lowering the temperature, it is possible to reduce No. in the second stage. That is, the generation of No, which is the main component of NOx, is generally described by the following equation, (No]=C(C1/T) [N2][02]
t[NO] No concentration in combustion gas [N2] N concentration in combustion gas [02] o! in combustion gas It has become clear that most of the production amount of 1 degree C, C1 constant T and the residence time No of the combustion gas is determined by the temperature T of the combustion gas.

Since the temperature of the combustion gas is mainly determined by heat radiation from the wall of the primary combustion chamber 1 to the secondary air flowing through the gap 4, the degree of reduction is determined by the amount of heat transferred from the primary flame to the wall. However, in the above configuration, the amount of heat transfer is determined by the area of the wall surface of the primary combustion chamber 2.
There is a limit to xization. For this first step, it is necessary to increase the size of the primary combustion chamber and secure the entire heat transfer area. but,
The enlargement of the primary combustion chamber also has the disadvantage of being easily deformed, which not only complicates the single-combustion structure which requires reinforcement, but also increases manufacturing costs.

The present invention was made in view of this point, and is an object of directly cooling the primary flame to reduce the number of no-works.

A technical means to solve the problem is to provide a cooling pipe by penetrating the primary combustion chamber to directly cool the primary flame.

Effect The effect of this technical means is as follows. That is, a fluid such as air flows through the cooling pipe, and the primary flame is directly cooled. As a result, the temperature of the primary flame (that is, unburned gas) generated in the primary combustion chamber is sufficiently lowered, making it possible to reduce NOx.

EXAMPLE Hereinafter, one example in which the present invention is applied to a hot air heater will be described based on the accompanying drawings. In FIG. 1, 1 is a burner, and the mixture chamber has a circular cross section and a flame hole part 6 thereon, and a large number of slit-shaped flame holes 8 are provided on both sides of this flame hole part 6. There is. The burner 1 is provided at the lower part of the primary combustion chamber 2. Furthermore, this primary combustion chamber 2 is surrounded by a secondary combustion chamber 3 and a guide plate 10 with a gap 4 in between. Ma1ko,
It passes through the primary combustion chamber 2 and further passes through the secondary combustion chamber 3 and the guide plate 1.
A cooling pipe 11 that also passes through the burner 1 is provided in the upper part of the burner 1, and its both ends are opened as a cooling air intake 12 and a cooling air outlet 13.

The above constitutes the combustion section of this hot air heater, and a hot air fan 14 is provided at the bottom of the combustion section, 15 is an air intake port, and 16 is a hot air outlet.

Next, the operation of the configuration of this embodiment will be explained.

First, the mixture of fuel and air supplied from the mixture chamber 5 starts to burn in the flame hole section 6 and each flame hole 8, and the flame collides with the inner wall surface of the primary combustion chamber 2, and the flame moves upward in the flow direction. It is converted into a gas and goes to the upper part of the primary combustion chamber. During this time, the combustion reaction takes place incompletely due to lack of oxygen, and combustion gas (unburnt gas) is produced. This combustion gas is transferred to the secondary flame hole section 7.
The secondary combustion chamber 3 and the guide plate 1 are supplied with secondary air flowing in from the air suction port 15 through the gap 4 near the secondary combustion chamber 3 and the guide plate 1.
Secondary combustion occurs in the space formed by 0 and the combustion is completed.

10,000, cooling air intake 12 by hot air fan 14
The air sucked from the primary flame absorbs heat from the primary flame in the cooling pipe 11, flows from the cooling air outlet 13 to the hot air path, and is mixed with combustion gas (exhaust gas after complete combustion). This air-fuel mixture is guided to the lower part of the hot air heater by the hot air fan 12, becomes hot air, and is blown out from the hot air outlet 16. In this embodiment, r
This air lowers the temperature of the primary flame by heat transfer within the cooling pipe 11. As a result, the amount of NOx generated in the primary flame can be reduced.

In this embodiment, air is forcibly guided into the cooling pipe, but in another embodiment (not shown), the cooling pipe may be provided at an angle to create a natural draft of the air. Thus, the same effects as in this embodiment can be obtained.

Effects of the Invention As described above, according to the combustion apparatus of the present invention, the following effects can be obtained.

(1) By providing a cooling pipe in the primary combustion chamber, the temperature of the primary flame can be lowered by heat transfer, so NO in the primary flame can be reduced.
The amount of NOx produced is reduced, and as a result, the amount of NOx produced can also be reduced in the subsequent secondary combustion.

(2) By providing a cooling pipe in the primary combustion chamber, the temperature of the primary flame can be lowered by heat transfer, so there is no need to expand the primary combustion chamber to increase the heat transfer area, so compared to conventional The primary combustion chamber can be made smaller.

Furthermore, no special reinforcement is required to prevent thermal deformation. Moreover, an increase in manufacturing costs can also be prevented.

[Brief explanation of the drawing]

FIG. 1 shows a combustion device according to an embodiment of the present invention.
= A cross-sectional view showing a hot air heater, FIG. 2 is a vertical cross-sectional view of a conventional combustion device, and FIG. 3 is a cross-sectional view thereof. 1... Burner, 2... Primary combustion chamber, a
...Secondary combustion chamber, 5...Mixture chamber, 6
... Flame hole part, 7 ... Secondary flame hole part, 8-.
...Flame hole, 9...Fin, 11...Cooling pipe. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure /-Hai-Yi 1 2--/

Claims (1)

[Claims] a burner consisting of a mixture chamber and a flame hole provided in the upper part of the mixture chamber; a primary combustion chamber having the burner inside and having a secondary flame hole provided in the upper part; and the primary combustion chamber. A combustion device comprising a secondary combustion chamber surrounding an outer wall of the chamber with a gap, and a cooling pipe penetrating the primary combustion chamber provided above the burner.