JPH03156204A - Combustion device - Google Patents

Abstract

PURPOSE:To restrain generation of NOx and prevent the temperature of parts of a burner port unit and a radiating body from rising excessively by providing the burner port unit at the upper part of a vaporizer, providing a flame holding ring around said unit, and providing a radiating body with its outer periphery in contact with secondary combustion flames at the upper part of said unit. CONSTITUTION:A burner port unit 19 consists of an inner cylinder 13, wire nets 16, and cap 18, while a flame holding ring 5 is provided around the unit 19. The unit 19 and the ring 5 are mounted on the upper part of a vaporizer 1. Primary combustion flames 10 are cooled by a radiating body 20 mounted closely on a cap 18 above the unit 19, wire nets 16 comprising heat resisting metal or ceramic material, etc., and the ring 5, so that NOx generation is reduced, while, at the same time, since the body 20 is provided in secondary combustion flames 11, the temperature of the flame 11 is caused to fall and further low NOx generation can be achieved. Since the body 20 is mounted on the unit 19, the unit 19 is not directly heated, preventing thereby the temperature of the parts thereof, particulary the nets 16, from rising excessively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combustion device that injects and burns a flammable air-fuel mixture from a flame port unit.

[Conventional technology]

FIG. 15 shows a side cross-sectional view of a combustion apparatus equipped with a conventional nitrogen oxide (hereinafter referred to as NO) reduction measure disclosed in, for example, Japanese Patent Application Laid-Open No. 81-259010. Figure 16 is the 15th
It is a front view showing a part of the figure. In Figure 15, 13
1 is an inner cylinder having a plurality of flame holes 15 and a wire mesh 1B tightly wrapped around the outer surface thereof, and 18 is a cap located on the upper part of the inner cylinder 13.

These inner cylinders 13. Wire mesh 16. The cap 18 constitutes a flame hole unit 19.

Reference numeral 20 denotes a plurality of heat radiators made of heat-resistant metal material, ceramic material, etc., which are placed in contact with or close to the outside of the wire mesh 16. 2 is an electric heater embedded in the outer wall of the vaporizer 1, 14 is a constriction part, and the inner cylinder 13. Together with the heat sink 20, they are each placed and fixed on the upper part of the vaporizer 1.

Reference numeral 8 indicates a blowing pipe having one end connected to the vaporizer 1 and the other end connected to the combustion blower 9, and reference numeral 12 having one end connected to the vaporizer 1 and the other end connected to the pump 1.
This is a fuel supply pipe connected to 7.

In the above configuration, first, the electric heater 2 is energized, and the vaporized body 1 is heated to a temperature necessary for vaporizing the liquid fuel (approximately 250°C to 300°C).
Preheat to ℃). After the preheating is completed, the blower 9 and pump 1f are driven to supply combustion air and liquid fuel into the vaporized body 1 through the blower pipe 8 and pipe 12.

Then, the liquid fuel is vaporized in the vaporizer 1, and the combustion air is ignited when this mixture is ejected from the flame hole 15, thereby forming a primary combustion flame 10 and a secondary combustion flame 11 and combusting it. do.

In the configuration of this conventional example, the primary combustion flame 1
By cooling this primary combustion flame 10, the amount of NOx emissions is reduced.

That is, when the heat sink 20 is inserted into the primary combustion flame 10, heat is transferred from the primary combustion flame 10 to the heat sink 20, and this heat is transferred from the heat sink 20 to the vaporized body 1 or as radiant heat to the surroundings. is dissipated into.

[Problem to be solved by the invention]

Conventionally, as described above, since the heat radiator 20 is inserted into the relatively high temperature primary combustion flame 10, the temperature of the heat radiator 20 rises excessively. In addition, the heat sink 20 is connected to the flame hole unit 1.
Because it is provided close to and opposite the flame hole 15 of No. 9,
The flame hole unit 19 receives a large amount of radiant heat from the heat radiator 20, which also promotes a temperature rise in each part of the flame hole unit 19. Such an excessive temperature rise causes deformation and damage to various parts of the flame port unit 19 and the heat radiating body 20 itself, and also causes problems in that backfire is likely to occur.

Furthermore, since the primary combustion flame 10 is excessively cooled, problems such as generation of a large amount of carbon monoxide (hereinafter referred to as CO) occur.

The present invention solves these conventional problems by suppressing the generation of large amounts of CO (and NO), ensuring stable combustion without flashback, and improving the performance of each part of the flame port unit and heat radiator. The purpose is to obtain a combustion device that prevents excessive temperature rise and improves durability.

[Means to solve the problem]

In the combustion device of the present invention, a flame hole unit is provided above the vaporizer, an annular flame holding ring is installed around the flame hole unit, and an outer peripheral portion of the flame hole unit has two
A heat radiator is provided in contact with the secondary combustion flame.

Further, in the combustion device of the present invention, the outer peripheral portion of the heat radiating body is partially cut out to form a comb blade portion, and the comb blade portion is inserted into the secondary combustion flame.

[Effect]

The combustion apparatus of the present invention cools the combustion flame, especially the secondary combustion flame, by inserting the outer peripheral part of the radiator into the secondary combustion flame, which has a relatively lower temperature than the primary combustion flame, so that CO2 can be reduced. It is possible to suppress the production of NO, without causing NO.

Furthermore, since the heat radiator is provided above the flame hole unit, the heat radiator no longer faces the flame hole portion of the flame hole unit, and an excessive temperature rise in the heat radiator is eliminated.

On the other hand, since the radiant heat from the radiator is radiated throughout the combustion chamber, there is no excessive temperature rise in each part of the flame port unit, and stable combustion without backfire can be achieved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, the same reference numerals as in FIG. 13 indicate the same or equivalent locations.

In FIG. 1, reference numeral 13 indicates an inner cylinder having a plurality of flame holes 15 and a wire mesh 16 tightly wrapped around the outer circumferential surface, and reference numeral 18 indicates an inner cylinder 13.
It is a cap that closes the upper opening of. These inner cylinders 13
．． Wire mesh 16. and the flame hole unit 1 by the cap 18.
Reference numeral 5 constituting 9 is an annular flame holding ring provided around the flame hole unit 1, and the flame hole unit 19 and flame holding ring 5 are installed above the vaporizer 1.

Reference numeral 2 denotes an electric heater embedded in the side wall of the vaporizer 1, and 14 is a constriction portion, which is fitted and fixed to the upper part of the vaporizer 1. 2
0 is a heat radiator made of a heat-resistant metal material, a ceramic material, or the like and placed in close contact with the cap 18 on the upper part of the flame hole unit 19.

8 is a blow pipe whose one end is connected to the vaporizer 1, 12 is a pipe provided coaxially within the blower tube 8, and 21 is a special screw fixing the flame hole unit 19 and the heat sink 20 to the vaporizer 1. It is embedded and fixed integrally in the constriction part 14. 20a is a mounting screw hole formed in the heat sink 20, and 22 is a nut.

Next, the operation of this device will be explained.

First, turn on the power switch (not shown) and turn on the electric heater 2.
The vaporized body 1 is preheated to a temperature (approximately 250° C. to 300° C.) necessary for vaporizing the liquid fuel. After preheating is completed, when the blower and pump (both not shown) are driven, the liquid fuel and combustion air flow into the vibrator 12. Vaporized body 1 passes through air pipe 8
The liquid fuel enters the inner cylinder 13 and the cap 18, where it is vaporized, and then enters the space within the inner cylinder 13 and the cap 18.
The mixture becomes flammable in the space inside, and is rectified into the flame hole 15.
It squirts through the wire mesh 16. When this air-fuel mixture is ignited by an ignition means (not shown) such as a discharge spark, a primary combustion flame 10 and a secondary combustion flame 11 are formed and burned.

In general combustion equipment, the primary air ratio μ is usually set to μ
, = 0.7 to 0.8, the flame hole 1 of the inner cylinder 13
The primary combustion flame 10 formed on the combustion chamber 5 is fuel-rich. Therefore, the unburned fuel, CO, etc. of the primary combustion flame 10 react with the surrounding secondary air to form the secondary combustion flame 11 so as to surround the flame hole unit 1, completing the combustion reaction.

The heat sink 20 is inserted into the secondary combustion fire #A11,
The secondary combustion flame 11 is prevented from spreading 9 by the flame holding ring 5, and the formation position of the secondary combustion flame 11 is regulated without changing in the radial direction even when the combustion amount changes.
By making the diameter of the flame holding ring 5 approximately the same as that of the flame holding ring 5, the heat radiating body 20 is not exposed from the secondary combustion flame 11.

During combustion, the heat transferred from the combustion flame to the metal 1118 and the flame-holding ring 5 is radiated by conduction or radiation. Furthermore, by pushing the heat radiator 20 into the secondary combustion flame 11, the heat is radiated from the secondary combustion flame 11. A large amount of the heat transmitted to the body 20 is radiated mainly by radiation, and the secondary combustion flame 11 is cooled.

The main component of N08 generated by combustion is NO. It is well known that the main component of NO is generated in and immediately adjacent to the primary combustion flame 10, but there is also a considerable amount of NO in the secondary combustion flame 11, and it is necessary to cool this secondary combustion flame 11. However, the inventors have discovered that considerable reduction in NOx can be achieved.

According to the combustion device of this embodiment, the wire mesh 1B and the flame-holding ring 5
At the same time, the primary combustion flame 10 is cooled and the N08 generated in and near the primary combustion flame 10 is reduced. The temperature of the next combustion flame 11 is lowered, and the NO
x. If the diameter of this heat sink 20 is much smaller than the secondary combustion flame 11, the effect of low NO will be reduced. By inserting the heat radiator 20 at a position in contact with the inside of the secondary combustion flame 11, a remarkable effect is achieved in reducing NO.

In addition, the flame stabilizing ring 5 serves to ensure the stability of the combustion flame by preventing the occurrence of blowouts, etc., and to prevent the spread of the secondary combustion flame 11 to prevent the secondary combustion flame from spreading due to changes in the air ratio and combustion amount. It has the function of stabilizing the formation position of 11.

Here, as shown in FIG. 1 and FIG.
is prevented from being exposed to the outside from the secondary combustion flame 11,
Prevent large amounts of CO from being generated and maintain safe combustion at all times.

According to the test results of the present inventors, in a combustion apparatus equipped with the flame hole unit 19 of the above embodiment, the NO and CO emission characteristics with and without the radiator 20 are as shown in FIGS. 3 and 4. be.

In this way, by cooling the primary combustion flame 10 with gold ml B and the flame-holding ring 5, it is of course possible to reduce the amount of paper NO, as in the past. It can be seen that by inserting it into the flame 11, a further reduction of about 30% in NO□ can be achieved without deteriorating the CO characteristics.

The figure also shows the results obtained when the heat radiator 20 shown in the conventional example was inserted into the primary combustion flame 10.

In the case of the conventional example, the results for No. are slightly better than those of the present example, but the characteristics for CO are poor, especially at low combustion amounts. This is because the primary combustion flame 10 is excessively cooled.

In addition, in this embodiment, the heat radiator 20 is connected to the flame hole unit 1.
9, the radiant heat is dissipated throughout the combustion space, does not directly overheat the flame hole unit 19, and prevents excessive temperature rise of each part of the flame hole unit 19, especially gold 1R1B.

Due to these effects, it is possible to prevent deformation and damage to not only the heat radiating body 20 itself but also each part of the flame hole unit 19, and improve durability.

Here, the test results of the present inventors regarding the temperature characteristics of the wire mesh 1B are shown in FIG.

FIG. 5 is a plot of the temperature of the wire mesh 18 against the amount of combustion based on the test results of the inventors, and taking into account abnormal situations during actual use, the primary air ratio μ at which the temperature of the wire mesh 1B is the highest is determined. , =0.9. Heat sink 20
Compared to the case where there is no combustion at all, when the fuel is inserted into the primary combustion flame 10 of the conventional example, the temperature rises more sharply, reaching as much as 1000°C. On the other hand, according to the examples of the present invention, this temperature increase is also painful, and it can be seen that the temperature is within a sufficiently usable range below the heat moisture resistance of ordinary wire mesh materials.

Therefore, stable combustion without any fear of backfire can be achieved.

Next, other embodiments of the present invention will be described.

What is shown in FIGS. 6 and 7 is a second embodiment of the present invention, in which the outer peripheral part of the heat sink 20 is partially cut out to form a comb blade part 20b, so that the secondary combustion flame 11 By increasing this contact area of the secondary combustion flame 11 without disturbing the -
This allows the cooling effect to be increased.

Moreover, what is shown in FIG. 8 and FIG. 9 is a third embodiment of the present invention, in which a part of the comb blade portion 20b of the heat radiating body 20 is arranged vertically upward almost directly above the flame-holding ring 5. By bending it, the cross section is made into a truncated shape, further increasing the contact area with the secondary combustion flame 11, and at the same time increasing the heat radiation area, thereby improving heat radiation and lunar radiation efficiency.

Moreover, what is shown in FIGS. 10 and 11 is the fourth embodiment of the present invention.
This is an embodiment of the cap 18 on the upper part of the flame port unit 19.
The cap 18 is integrally formed with the comb blade portion 20b on the outer periphery.
This also serves as a heat sink 20.

Furthermore, what is shown in FIGS. 12 and 13 is a fifth embodiment of the present invention, in which the comb blade portion 20b of the heat radiating body 20 is formed to have a U-shaped cross section, so that the secondary combustion flame 11 Among them, the heat dissipating body 20 can be located in a particularly high temperature area.

Furthermore, what is shown in FIG. 14 shows a sixth embodiment of the present invention, in which a predetermined gap 23 is provided between the heat sink 20 and the cap 18.
By reducing the heat conduction from the flame hole unit 19 to the flame hole unit 19, the temperature rise of the flame hole unit 19 is further suppressed, and the secondary combustion flame 11 can be cooled more effectively.

〔Effect of the invention〕

As described above, according to the combustion apparatus of the present invention, the heat radiator is provided at the upper part of the flame hole unit, and the outer circumference of the heat radiator is brought into contact with the secondary combustion flame, thereby inducing the generation of CO. The temperature of the secondary combustion flame is lowered without
The amount of O generated can be reduced, and the harm to human health can be further reduced compared to conventional methods that cool the primary combustion flame.

In addition, since the comb blade part is formed on the outer peripheral part of the heat radiator that comes into contact with the secondary combustion flame, the comb blade part increases the contact area with the flame and enhances the cooling effect, as well as rectifying the flame. Lifting without disturbing the secondary combustion flame
This has the effect of providing a stable combustion state that is less likely to cause blowouts.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main part showing a combustion device according to an embodiment of the present invention, Fig. 2 is a plan view of its heat radiator, and Figs. 3, 4, and 5 are examples of the present invention and conventional examples. Characteristic comparison diagrams based on the results, FIGS. 6 to 14 are sectional views of main parts of a combustion device and a plan view of a heat radiator showing other embodiments of the present invention, and FIG. 15 is a cutaway diagram showing a conventional combustion device , FIG. 16 is a front view showing a part thereof. In the figure, 1 is a vaporized body, 5 is a flame holding ring, 10 is a primary combustion flame, 11 is a secondary combustion flame, 15 is a flame hole, 1B is a wire mesh, 1
8 is the cap, 1st is the flame hole unit, 20 is the heat sink, 2
0b is a comb blade portion. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (7)

[Claims] (1) A flame hole unit is installed above the vaporizer that vaporizes liquid fuel, a flame holding ring is provided surrounding the outer periphery of the flame hole unit at a predetermined interval, and a flame holding ring is provided at the top of the flame hole unit. A combustion device comprising a heat radiator whose outer peripheral portion is in contact with a secondary combustion flame. (2) The combustion apparatus according to claim (1), wherein the heat radiator is formed integrally with the flame hole unit. (3) The combustion device according to claim (1), wherein the heat radiator is formed into a disk shape having a diameter equivalent to that of the flame-holding ring. (4) The combustion device according to claim (1), characterized in that the outer peripheral portion of the heat radiator is partially cut out to form a comb blade portion, and the comb blade portion is brought into contact with the secondary combustion flame. . (5) The combustion device according to claim (4), wherein the comb blade portion is bent upwardly at a portion directly above the flame-holding ring and has an L-shaped cross section. (6) Claim (4) characterized in that the comb blade portion is bent into a U-shaped cross section so that a portion located below the upper surface of the flame hole unit is in contact with the secondary combustion flame. Combustion device as described. (7) The combustion apparatus according to claim (6), wherein the heat radiator is installed with a predetermined gap from the flame hole unit.