JPS63279010A - Burning equipment - Google Patents

Abstract

PURPOSE:To prevent overheating of an inner burner port body, to stabilize combustion freed from deterioration of a material, deformation, and backfire, and to prevent production of NOx, by a method wherein an air-fuel ratio of air-fuel premixture injected through the blow holes of the inner burner port body is increased to a value higher than that of air air-fuel premixture injected through the blow hole of an outer burner port body. CONSTITUTION:With a heater 41 energized, an evaporating cylinder 40 preheated, and a blower 45 and a pump 47 driven, liquid fuel and primary air air in an amount exceeding a theoretical air amount are fed in the evaporating cylinder 40 to produce total primary air-fuel premixture, which is guided into passages 52 and 56 through the central part of a mixing plate 42 and an which a high swirling flow is exerted for injection to a combustion chamber 57. When the air-fuel premixture is ingnited by an ignition electrode 62, a swirl blue flame zone 58 is formed for combustion. A free gap 59 is formed by means of the inner peripheral wall of an outer burner port body 49, the outer peripheral wall of an inner burner port body 53, and the outlets of blow holes 50 and 54 to form an annular and filmy swirl blue flame. Air is further added to the air-fuel premixture present in the passage 56 in the inner burner port body 53 by means of a primary air branch pipe 44a to increase the air-fuel ratio, and flame is prevented from being adhered to the blow holes 54 due to an increase in temperature occasioned by deficiency in dissipation of heat of the inner burner port body 53.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a combustion device that ejects a flammable air-fuel mixture from a flame hole body and burns it, and is used for purposes such as heating.

Conventional technology Conventional combustion devices of this type are shown in FIGS. 4 to 6.

The configuration shown in FIG. 4 is disclosed, for example, in Japanese Unexamined Patent Publication No. 17819/1984, in which 1 is an outer cylinder, 2 is a wire mesh tube, 3 is a mounting bracket for attaching one end of the wire mesh tube 2 to the outer tube 1, and 4 is wire mesh tube 2
A cap that closes the other end; 5 is a pot-shaped vaporizing tube; 6 is a mixing plate disposed at the upper opening of the vaporizing tube 5; 7 is a heater; 8 is an air nozzle inserted into the side wall of the vaporizing tube 5. , 9 is a combustion nozzle located approximately in the center of the air nozzle 8, 1o is a discharge ignition electrode extending inside the wire mesh cylinder 2, 11 is a fan that supplies combustion air into the vaporizer cylinder 5, and 12 is a fan that supplies combustion heat to the inside of the vaporizer cylinder 5. 13 is an air supply pipe connecting the fan 11 and the air nozzle 8; 14 is a resistor disposed in the middle of the air supply pipe 13; 15 is a constant oil level device communicating with the fuel nozzle 9;
Reference numeral 6 denotes a pressure guiding pipe that guides the fan discharge pressure on the upstream side of the resistor 14 into the constant oil level device 15.

Next, the operation of the above-mentioned conventional combustion device will be explained.

When the heater 7 is energized and the vaporization tube 5 is heated to a predetermined temperature, the fan 11 is activated to supply combustion air into the vaporization tube 5 through the air nozzle 8 . At this time, the pressure generated by the resistance of the resistor 14 and the airflow resistance of the air nozzle 8, that is, the fan discharge pressure, is guided to the oil level device 15 by the impulse pipe 16, and pressurizes the fuel in the oil level device 15. The fuel is discharged from the fuel nozzle 9. The fuel supplied into the vaporization cylinder 5 is vaporized on the heated inner wall of the vaporization cylinder 5, mixed with combustion air, and becomes a premixture with an excess air ratio μ of 1.0 to 1.6. 6 and ejects inward from the wire mesh tube 2. The ejected premixture is ignited by the ignition electrode 1o, and the wire mesh cylinder 2
Complete combustion takes place on the inner surface of the

FIG. 5 shows, for example, a configuration shown in Japanese Utility Model Publication No. 59-3209, in which a combustion tube 18 made of a wire mesh or a porous metal plate is provided inside an outer tube 17, and this combustion tube 18 is connected to an inner combustion tube 19 and an outer combustion tube. It is composed of a cylinder 20 and is provided with flow paths 21 and 22 for guiding gas from the inside and the outside, and has an outer peripheral surface 19a of the inner combustion cylinder 19 and an inner peripheral surface 2 of the outer combustion cylinder 20.
0a and 0a are respectively combustion surfaces. 23 is a frame body, 24 is a mixing tube, 25 is a gas nozzle, 26 is a flow divider plate, and 27 is an ignition fuse tube.

Next, the operation of the above-mentioned conventional combustion device will be explained. The gas ejected from the gas nozzle 25 becomes a mixed gas mixed with a predetermined amount of air in the mixing tube 24, and is divided into flow paths 21 and 22, one of which flows outward from the inside of the inner combustion tube 19, and the other flows outward. From the outside to the inside of the combustion tube 20, a uniform gas jet is obtained on each combustion surface 19g, 20g, and when ignited there, it burns in close contact with each combustion surface 19m, 20m.

In the conventional examples shown in FIGS. 4 and 5, the premixture is ejected from a wire mesh or a thin porous metal plate as a flame port, and is brought into close contact with these surfaces to form a combustion flame. Most of these are all-primary air combustion types that supply more than the theoretical amount of air as primary air to the fuel for combustion, which lowers the combustion load at the flame nozzle and thins the combustion reaction zone, and the flame nozzle itself is 800 mm The purpose is to make the flame red-hot to ~900'C to promote heat dissipation, lower the flame temperature, and suppress the generation of nitrogen oxides (hereinafter referred to as NOx).

In these cases, the wire mesh, etc. that serves as the flame outlet is in a red-hot state, and due to this mutual interference and heat reflection from other objects, the flame outlet itself becomes high temperature, which tends to cause material deterioration and deformation, which poses problems in terms of durability. The temperature of the upstream premixture also increases, making flashback very likely. Compared to gas fuels such as city gas and propane, this phenomenon occurs when the liquid fuel and primary air are supplied to a vaporizer equipped with a heater to create a premixture and combust.
This was an even bigger problem because it was preheated to 300°C.

In the configuration shown in Fig. 4, the oil premixture is guided and combusted from between the wire mesh tube 2 and the outer tube 1 toward the inside of the wire mesh tube 2, but the high temperature wire mesh tube 2 is opposed to it. , and because the outer cylinder 1 is close to the wire mesh tube, the wire mesh tube 2 itself tends to become extremely hot, and the pre-mixture preheated in the vaporizing tube 5 is further heated to the cap 4, the outer tube 1, and the wire mesh tube. There were problems with durability and the tendency to backfire due to high temperatures caused by conduction and radiation.

Further, the conventional example shown in FIG. 5 has a combustion tube 19 corresponding to the flame port.
20 and 10 to 20 InIl, and in order to burn them on opposing surfaces, the combustion tube 19.2 is formed by mutual interference.
0 became higher in temperature than the conventional example shown in FIG. 4, and had the same basic problem.

In FIG. 5, heat dissipation is obtained from the outer combustion tube 20 and the premixture upstream thereof through the outer tube 17, but heat dissipation from the inner combustion tube 19 is cut off, and the outer combustion tube 2o The radiant heat from the air causes a high temperature, which further increases the combustion speed of the premixture, brings the flame into close contact with the combustion tube 20, and further increases the temperature.At the same time, the temperature of the premixture in the flow path 21 also rises, reducing durability and backfire. There is a problem that the amount of NOx generated increases, making it difficult to put it into practical use.

These temperature problems at the flame outlet can be improved to some extent by promoting heat dissipation using glass tubes, radiating fins, etc., and by setting the combustion load at the flame outlet to be small, but conversely, reducing the amount of combustion In this case, the ejection speed of the premixture from the flame port becomes slow, making it easy to cause backfire, and the flame becomes unstable due to combustion over a wide flame area, and the heat dissipation effect leads to supercooling of the combustion reaction temperature. Incomplete combustion components such as co and uc will be generated.

Therefore, in these conventional examples, even if set to the optimum conditions, NOx
It is only a certain limited amount of combustion that can reduce generation and satisfy complete combustion, and while adjusting the amount of combustion, the amount of combustion is limited to about 1, which is narrow and difficult to use in terms of economy and comfort when used for heating etc. It was a big problem.

FIG. 6 shows, for example, the configuration shown in Japanese Utility Model Publication No. 57-32345, in which 28 is a combustion tube provided with an air supply port 28A, 29 is a burner port plate with a burner port 29A open, and 30A is a mixing chamber 3.
31 is a partition wall, 32 is an outer cylinder constituting the air passage 33, 33A is an air pipe, and 34 is a primary air pipe connected to the end of the air passage 33, which communicates with the mixing chamber 30. do. 35 is a primary flame, and 36 is a combustion chamber.

37 is a secondary flame, 38 is a central part of the combustion chamber 36, and 39 is an outlet.

Next, the operation of the above-mentioned conventional combustion device will be explained. Air from the air pipe 33A is supplied in the tangential direction of the air passage 33, and the secondary air is discharged into the combustion chamber 36 at a constant angle with respect to the air supply hole 28A, forming a swirling flow. The fuel from the fuel pipe 34 and the air from the primary air pipe 34 are mixed to form a premixture, which is ejected from the flame port 29A. If it is ignited here, it will come into close contact with the flame port 29A, forming a primary flame 35 and a secondary flame in its wake, and combust.

The aim of this configuration is to mix the secondary air and premixture well to reduce soot generation, reduce the amount of secondary air to improve combustion efficiency, and keep the amount of primary air relatively low. The aim is to lower the flame temperature and reduce the amount of NOx generated. However, even if the amount of primary air is reduced, a primary flame 35 is clearly formed in close contact with the flame port plate 29, and this primary flame 35 is still as high as 1500'C, so the amount of NOx generated in this area is When used in room heaters, etc., there is a problem of negative effects on the human body.

In addition, since the primary flame 35 is formed by adhering to and partially penetrating into the flame port 29A, the flame port plate 29 itself becomes high temperature and is prone to backfire.When white kerosene is used as fuel, this tendency becomes noticeable when adjusting the combustion amount. There are very few drawbacks.

Furthermore, secondary air is swirled and supplied to the combustion chamber 36,
Since this secondary air flows along the inner wall surface of the combustion tube 28, it does not reach the center of the burner port plate 29 sufficiently, and the burner port 29 here
Secondary air is not supplied to the vicinity of the premixture and primary flame 35 at the outlet 9A.

Therefore, an extreme imbalance occurs in the supply of secondary air between the outer periphery and the center of the flame port plate 29, making it difficult to improve the overall combustion efficiency.From this point of view, it is also possible to suppress flashback and reduce the amount of NOx. There was a limit.

In addition to the conventional examples shown in Figures 4 to 6, other configurations for achieving low NOx are known; for example, there are configurations in which fuel and air are supplied to the combustion chamber by swirling, but complete combustion cannot be achieved. There were fundamental issues such as combustion noise, flashback due to the formation of primary flames in close contact with the flame nozzle, and high NOx emissions.

Problems to be Solved by the Invention In the conventional configuration as described above, even if the amount of NOx generated is suppressed and the combustion amount is widely adjusted, backfire, flame port deterioration,
This was a major problem because there was no combustion device that could achieve complete combustion without causing deformation.

The present invention solves such conventional problems, and N O
By significantly suppressing the occurrence of The purpose is to provide combustion equipment.

Means for Solving the Problems In order to solve the above problems, the combustion device of the present invention includes an annularly formed inner flame hole body, an outer flame hole body, and a flame hole body formed between the inner and outer flame hole bodies. A combustion chamber, a plurality of pores provided in the inner and outer flame holes, a passageway that leads all the primary premixture to these pores, and an air ratio of the premixture ejected from the pores provided in the inner flame hole. A combustion device in which the air ratio of the premixed gas is set higher than the air ratio of the premixed gas ejected from the pores provided in the outer flame hole body, and the mixture is combusted in the combustion chamber.

Effects The present invention has the above-described configuration, and by making the air ratio of the premixture jetting out from the pores of the inner flame hole body higher than the air ratio of the premixture jetting out from the pores of the outer flame hole body, the inner flame Prevent flame from adhering to the pores and the pores. This prevents overheating of the inner flame hole body, allowing stable combustion without material deterioration, deformation, or flashback, and suppressing the generation of NOx.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings of FIGS. 1 to 3. Reference numeral 40 denotes a vaporizing cylinder having a heater 41, and a mixing plate 42 in which a plurality of through holes 43 are formed is connected to the upper end of the vaporizing cylinder. 44 is a blower 45) This is a communicating vaporizer cylinder 40
The blower pipe 44a that opens on the side wall of the main body is a branch pipe for primary air. A fuel pipe 46 supplies liquid fuel into the vaporization cylinder 40 from a pump 47. Reference numeral 48 denotes an outer cylinder, which has a plurality of air holes 50 inside thereof, and has a bottom plate 51 having a hole in the center at its lower end, which is connected to the mixing plate 42 . 5
Reference numeral 2 denotes a passage for the entire primary premixture formed between the outer cylinder 48 and the outer flame hole body 49, and 53 denotes an inner flame hole body provided with a plurality of air holes 54 located inside the outer flame hole body 49. , are connected to the bottom plate 51. 55 is a cap, and 56 is a premix passage. Reference numeral 57 represents a combustion chamber formed between the outer flame hole body 49 and the inner flame hole body 53, and 58 represents an annular rotating gastritis zone. Reference numeral 59 indicates a gap between the outer flame hole body 49 and the swirling blue flame zone 58, and numeral 60 indicates a gap between the inner flame hole body and the swirling blue flame zone 58. 61 is an exhaust pipe, and 62 is an ignition electrode for generating discharge sparks. Solid arrows in the figure indicate the flow of primary air and premixture.

FIG. 2 is a cutaway view taken along line A--A in FIG. 1, and the third factor is a graph showing a relative comparison of the amount of NOx generated with respect to the primary air ratio of the premixture.

Next, the operation in the above configuration will be explained. First, heater 41
When electricity is supplied to preheat the vaporization cylinder 40 to 250 to 300°C, and then the blower 45 and pump 47 are driven, liquid fuel and primary air that is more than the theoretical air amount are supplied into the vaporization cylinder 40, where all the primary The mixed gas is guided through the center of the mixing plate 42 into passages 52 and 56. This entire primary premixture is injected into the combustion chamber 57 from the air holes 50 provided in the outer flame hole body 49 and the air holes 54 provided in the inner flame hole body 53.

At this time, since the air holes 50 and 54 are provided in the same swirling direction, all the primary premixed gas is given a strong swirling flow to the combustion chamber 57 and is ejected. When this is ignited by the spark of the ignition electrode 62, a swirling gastritis band 5B is formed and burned. This rotating gastritis zone 58 is formed by setting the outer gastritis hole body 49 at an optimal air ratio.
, the outer peripheral wall of the inner flame hole body 53, and the pores 50.54.
A free gap 59 of 1 to 3M is formed from the outlet of the flame, and a circular blue flame becomes a thin film.

In this combustion state, the inner peripheral wall of the outer flame hole body 49 and the rotating blue flame zone 5
8 and the free gap 6o between the outer peripheral wall of the inner flame hole body 53 and the swirling blue flame zone 58, the entire primary premixture ejected from the air holes 50.54 is mixed with the retaining gas from the swirling blue flame zone 58. Some of it gets mixed in and accelerates the temperature rise of the entire primary premixture.
A circulation effect occurs that makes the mixture more lean.

Further, in the present invention, air is further added to the premixture in the passage 56 in the inner flame hole body 53 by using the primary air branch pipe 44 to increase the air ratio. This can prevent the flame from coming into close contact with the air holes 54 due to a temperature rise due to insufficient heat radiation of the inner flame hole body 53.

These prevent the generation of local high temperature areas in the flame zone and
The amount of Ox generated can be greatly reduced, and at the same time, overheating of the inner flame hole body 49, outer flame hole body 53, and premixture can be prevented, and durability can be improved and stable combustion without backfire can be achieved. It will be done. This combustion state exhibits the same action and effect even if the combustion amount is greatly changed, and the combustion amount adjustment period can be increased to 1/3 or more.

Also, as shown in Figure 3, when the primary air ratio is low, NO
x The amount generated increases. This is because when the primary flame is formed in close contact with the pores, the primary flame itself reaches a high temperature of 1500°C or more, and the above-mentioned effect of circulating exhaust gas into the premixture is lost. .

The pores 50 of the outer flame hole body 49 and the pores 54 of the inner flame hole body 53
A more free swirling blue flame @58 can be formed by arbitrary setting of the primary air ratio of the pores 50°54; This is the point at which the above-mentioned free swirling blue flame band 58 is formed, where the amount of NOx generated suddenly shows a large decrease.

Although the embodiment uses liquid fuel, it goes without saying that similar actions and effects can be obtained using gas fuel such as city gas or propane.

Effects of the Invention As described above, the combustion apparatus of the present invention provides the following effects.

(1) By setting the air ratio of the premixture ejected from the pores provided in the inner flame hole body to be higher than the air ratio of the premixture ejected from the pores provided in the outer flame hole body, the inner flame hole body and Since the flame is prevented from coming into close contact with the pores and the inner flame pore body is not overheated, material deterioration, deformation, etc. do not occur, and durability can be improved.

(2) At the same time, since the temperature of the inner flame hole body itself and the premixed gas inside it does not rise significantly, flashback is prevented and stable combustion can be obtained.

(3) It is possible to prevent the generation of local high temperature areas in the flame zone, and to improve the indoor environment in particular without increasing the amount of NOx generated.

(4) Stable combustion can be obtained even if the combustion amount is adjusted greatly to ⅓ or more, and economical efficiency and comfort can be improved.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a combustion device according to an embodiment of the present invention, and FIG.
The figure is a cross-sectional view taken along line A-A in Figure 1, Figure 3 is a characteristic diagram showing the correlation between the primary air ratio and the amount of NOx generated, and Figure 4.
FIGS. 5 and 6 are side sectional views showing conventional combustion devices, respectively. 49... Inner flame pore body, 50... Stomata, 5
2...Passway, 53...Outer flame hole body, 54
...Stomata, 56...Passage, 57...
...combustion chamber. Name of agent: Patent attorney Toshio Nakao and 1 other person49
- Inner flame hole body, 5D, 5G - At once 52.56 - Passage 1st diagram Riichi External hole body 57 - Burning mouse melt 2r! ! 1 Happy 3rII -Next g! Kibi (machi → Figure 4 Figure 5)

Claims (1)

[Claims] An inner flame hole body and an outer flame hole body formed in an annular shape, a combustion chamber formed between the inner flame hole body and the outer flame hole body, and a plurality of pores provided in the inner flame hole body and the outer flame hole body. and a passage for guiding the entire primary premixture to the pores, and the air ratio of the premixture jetted out from the pores provided in the inner flame hole body is adjusted to the premixed mixture jetted out from the pores provided in the outer flame hole body. A combustion device in which combustion is performed within the combustion chamber with the air ratio set higher than that of air.