JPH0445314A - combustion device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to combustion devices such as water heaters and space heaters.

BACKGROUND OF THE INVENTION In recent years, the problems of global warming and environmental destruction have attracted attention, and there has been a strong demand for lower NOx in combustion equipment related to these problems.

Conventionally, this type of combustion apparatus has a burner 26, a combustion chamber 27, a heat exchanger 28, and an exhaust section 29 installed in close proximity to each other downstream of a fan 25 that supplies combustion air, as shown in FIG. There is. The burner 26 consists of a mixture chamber 30 and an air chamber 31, each having a flame port 32 and a secondary air port 33 at the downstream end.
have. Further, a uniform plate 34 is provided between the fan 25 of the air chamber 31 and the secondary air port 33 in order to equalize the distribution of secondary air.
A honeycomb lattice 35 was provided on the upstream side of 3 to direct the flow upward.

Problems to be Solved by the Invention In such a conventional combustion device, the NOx generated from the flame 36 placed on the burner 26 can only be reduced by devising the burner 26 itself; there were. In addition, in some industrial products, the secondary air port 33
Although attempts have been made to reduce NOx by spraying water onto the fuel, it has been difficult to put it into practical use because it increases the size of the equipment and significantly increases costs.

In addition, although the secondary air distribution is made uniform and rectified for combustion noise, it may be resonantly amplified in spaces such as the combustion chamber 27 and the air chamber 31, or the high frequency components of the fan 25 may be emitted from the exhaust section 29.
It had a more direct radiation problem.

The present invention solves the above problems, and aims to provide a combustion device that can reduce NOx and noise.

Means for Solving the Problems In order to achieve the above objects, the present invention provides a fan for supplying combustion air, a mixture chamber having a flame port at the downstream end, and a secondary air passage around the mixture chamber. a burner comprising an air chamber having a secondary air port which supplies secondary air to the flame port, and a baffle plate made of a porous material on the upstream side of the secondary air port; On the downstream side of the burner, there is a combustion chamber, a heat exchanger, an exhaust section, a water inlet section that supplies water to the heat exchanger, a hot water outlet section that supplies hot water to the terminal, and branches off from the water inlet section and is shut off. A communication pipe communicates with the current plate through a valve.

Operation In the above configuration, when the combustion device is operated, the shutoff valve is opened and water is gradually supplied from the communication pipe to the porous current plate. On the other hand, when the secondary air supplied by the fan passes through the baffle plate, it takes in moisture filled in the baffle plate through a number of small holes, and as a result, it acts on the flame as combustion air containing a large amount of moisture. do. At this time, the amount of heat for vaporizing the moisture can be radiated and cooled from the flame, and the flame reaction temperature can be lowered. Therefore, N.

The amount of X generated is small, and the above effects can reduce NOx. In addition, the current plate is made of a porous material, and in addition to the communication holes present in the material itself, it has many openings that even out the secondary air distribution, resulting in air rectification, uniformity, and sound absorption. Effect can be obtained. In addition, it stabilizes the secondary air supplied to the flame opening, stabilizes the flame itself, and absorbs pressure fluctuations that occur during combustion, resulting in resonance peaks that occur in spaces such as the air chamber and combustion chamber and in the exhaust area. is suppressed. Furthermore, the sound emitted from the blowing side of the fan is also absorbed.

Embodiment Hereinafter, a case in which an embodiment of the present invention is applied to a water heater will be described with reference to FIGS. 1 and 2.

As shown in the figure, on the downstream side of the fan 1, a burner 2, a combustion chamber 3, a heat exchanger 4, and an exhaust section 5 are provided in close contact with each other in this order. The burner 1 consists of a mixture chamber 6 and an air chamber 7,
Each has a flame port 8 and a secondary air port 9 at the downstream end. A rectifying plate 11 made of a porous material and having a large number of openings IO is provided between the secondary air port 9 of the air chamber 7 and the fan 10.

The rectifying plate 11 is made of a hygroscopic ceramic material and has a honeycomb-shaped opening 10, and the hole diameter is set to such an extent that ventilation resistance does not become large. The burner 2 has a gas block 12 having a function of adjusting the flow rate of gas fuel, the heat exchanger 4 has a water inlet part 13 having a function of adjusting the amount of water entering at the inlet, and a hot water outlet vibrator 14 at the outlet. It is connected to the hot water tap section 15. In addition, a shutoff valve 1 is branched from the water inlet section 13.
6, one side of which communicates with the current plate 11;
In the above configuration, when the hot water tap is opened and water begins to flow through the water heater body, the water flow is detected at the water inlet I3, and the fan 1 is activated by a command from a control block (not shown). Combustion air (indicated by the dotted chain arrow in the figure)
At the same time that water is supplied to the burner 2, the cutoff valve 16 is opened, and a portion of the water is supplied to the current plate 11 from the communication pipe 17. On the other hand, fuel is supplied to the gas block 12, and the control block (
(not shown), a flow rate determined according to the hot water supply load is supplied from the mixture chamber 6 to the flame port 8 by taking in a part of the air. Further, when passing through the baffle plate 11, the secondary air which has become highly humid by taking in moisture is released through the secondary air port 9, burns in the combustion chamber 3, becomes high-temperature combustion exhaust gas, and exchanges heat. Water that enters the vessel 4 and is supplied from the water inlet section 13 is heated by high-temperature exhaust gas in the heat exchanger 4, becomes hot water, passes through the hot water outlet section 15, and is supplied for hot water supply.

On the other hand, the low-temperature exhaust gas, which has been deprived of heat by the heat of evaporation of moisture contained in the secondary air, is discharged from the exhaust section 5 to the atmosphere.

Here, the flame 18 formed in the burner 2 is supplied with atomized moisture in addition to normal air, so that the heat amount of the flame 18 is taken away as heat of vaporization of the atomized moisture. In other words, the flame temperature decreases by the amount of heat of vaporization of the atomized moisture supplied through the current plate 11.

The amount of NOx generated depends on the flame reaction temperature, and the lower the flame reaction temperature, the smaller the amount of NOx generated, so the above action can reduce NOx. Also air chamber 7
A rectifying plate 11 made of a porous material that has a rectifying function, a uniform distribution function, and a sound absorbing function is installed inside the filter.
The secondary air supplied to the flame section 8 is stabilized, the flame itself is stabilized, and the pressure fluctuations that occur during combustion are also absorbed, reducing the resonance that occurs between the air chamber 7, the combustion chamber 3, etc., and the exhaust section 5. peak is suppressed. Furthermore, the sound emitted from the blowing side of the fan 1 is also absorbed, and the fan noise from the exhaust section 5 is also reduced.

Effects of the Invention As is clear from the description of the embodiments above, the combustion apparatus of the present invention provides the following effects.

1) Through a communicating pipe that branches from the water inlet and passes through a shutoff valve,
A part of the water is supplied to a baffle plate made of porous material installed in the air chamber, and as a result, the moisture-rich combustion air is supplied to the flame opening, which allows the amount of heat that vaporizes moisture to be radiated and cooled from the flame. , the flame reaction temperature can be lowered. Therefore, the amount of NOx generated depends on the flame reaction temperature, and the lower the flame reaction temperature, the smaller the amount of NOx generated, which can be reduced by the above action.

2) Since the rectifying plate is made of porous material and has multiple openings, it can rectify and evenly distribute the secondary air, stabilizing the secondary air supplied to the flame opening, and improving the flame. In addition to stabilizing itself, the sound-absorbing effect of a porous material absorbs pressure fluctuations that occur during combustion, creating an air chamber,
Suppresses resonance peaks that occur in spaces such as combustion chambers and the exhaust section.

Furthermore, the sound emitted from the blowing side of the fan can also be absorbed, reducing fan noise from the exhaust section.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the present invention applied to a water heater, FIG. 2 is a side view of the same, and FIG. 3 is a side view of a conventional example. l...Fan, 2...Burner, 3...
... Combustion chamber, 4 ... Heat exchanger, 5 ...
...Exhaust section, 6...Mixture chamber, 7...
Air chamber, 8...flame port, 9...secondary air chamber, 11...straightening plate, 13...water inlet, 15... ... Hot water outlet, 16 ... Shutoff valve, 17 ... Communication pipe. Name of agent: Patent attorney Shigetaka Awano Haka 1 person! 4～ 5 ・ 6 ゛Fan burner history room IIItt Martyr Lutai Qi Immediate Exhibition S Qi Air chamber Yi O Ikujikyo 9 list O View TL 5 16- Ro Ill Ben 17-1 Proverb gh W Figure zp+ Figure q

Claims (1)

[Claims] A fan for supplying combustion air, a mixture chamber having a flame port at a downstream end, and a secondary air passage forming a secondary air passage around the mixture chamber and supplying secondary air to the flame port. a burner comprising an air chamber having a port and a baffle plate made of a porous material on the upstream side of the secondary air port; a combustion chamber on the downstream side of the burner; a heat exchanger; and an exhaust section. A combustion device comprising: a water inlet section that supplies water to the heat exchanger; a hot water outlet section that supplies hot water to a terminal; and a communication pipe that branches from the water inlet section and communicates with the current plate via a shutoff valve. .