JPS58221305A - Burner - Google Patents

Abstract

PURPOSE:To miniaturize a burner by shortening its flames simultaneously extending the allowable fluctuation range of blast required for burning control by a method wherein air is jetted slowly in parallel with mixed gas near nozzle while it is jetted diagonally in the jetting direction of the mixed gas at the downstream side of the nozzle. CONSTITUTION:The mixed gas comprising the primary air and fuel flown into a mixing chamber 17 is flown from a blame port 9 to a combustion chamber through an air outlet 24 and clearance 25. The secondary air flown into air chambers 19, 15 is flown into auxiliary air chambers 21, 12 with its flow rate partly and properly controlled by throttles 20, 16 to be further decelerated and flown out into both sides of the flame port 9 from an auxiliary air outlet 23 to diffusion-mixed with the mixed gas forming stable small flames A at the end of the port. Most of the residual mixed gas is diagonally jetted in the downward direction from an air outlet 22 to flames B formed in both sides to be forcibly mixed with each other accelerating the burning reaction and simultaneously jetted at high speed from another air outlet 14 shortening the flame length.

Description

[Detailed Description of the Invention] The present invention applies to household combustion appliances such as water heaters and space heaters.
This invention relates to a combustion device that uses a fan or the like to perform forced combustion to shorten the flame length, thereby reducing the size of the combustion chamber and reducing the size of the combustion section.

Conventionally, one example of this type of combustion apparatus has a configuration as shown in FIG. The configuration of this device is such that in a space formed by joining a pair of bilaterally symmetric molded bodies 11o,
Mixture passage 111. A secondary air chamber 113 having a secondary air port 112 at the tip of the constriction portion and a burner element 115 having a burner port 114 integrally molded on both sides of the secondary air chamber 1130 are inserted and partitioned by the burner element 115 and the molded body 110. The two spaces are the mixture chamber 116 and the combustion chamber 11, respectively.
7.

In such a configuration, the mixture flows out into the mixture chamber 116 through the mixture passage 111, passes through the gap between the burner element 116 and the molded body 11Q, and reaches the flame port 114. The air-fuel mixture that has passed through the flame port 114 forms a flame on the flame port 114 as shown in the figure. On the other hand, the secondary air is
13, passes through the constriction part, is ejected from the secondary air port 112 provided at the tip, and is forcibly supplied to the flame.

In such a device, the ejection speed of the secondary air supplied from the secondary air port 112 is relatively low in order to shorten the flame length of the diffusion flame caused by unburned components such as H2 and CO that extend downstream. It is designed to be large, promoting mixing with unburned components and shortening the flame. If the ejection speed of the secondary air is increased here, the flame base formed on the flame port 114 in the vicinity of the secondary air port 112 will be disturbed without significantly affecting the stability of the flame. In other words, the flame that is formed becomes an unsteady flame, causing the flame band to break or the flame to go out, resulting in incomplete combustion. Therefore, as a countermeasure against this, the primary air ratio (- amount of primary air mixed with fuel/ A11 The theoretical air amount) is set to a large value (below the flammable limit on the rich fuel side), the combustion speed proportional to the -air ratio is reduced, and the flame base is stabilized.
~ Designed to make pre-mixed coal. However, setting a large negative air ratio to stabilize the flame base increases the combustion speed and brings the flame closer to the flame nozzle, which tends to cause vibratory combustion that causes red heat at the flame nozzle 114 and abnormal noise. There is a danger that Therefore, the combustion chamber can be made smaller by shortening the flame, but the permissible fluctuation range of the primary air ratio, that is, the amount of air blown, becomes narrower.On the other hand, as another conventional example, a pot-type combustion device for liquid fuel is shown in Fig. 6. A device having the configuration shown, 5. There is E. The configuration of this device includes a heating chamber 118 in the center and a combustion space control body 119 provided with a number of holes of different diameters, which is inserted into a 71ft trunk 121 to which a fuel pipe 120 is connected. A mixing chamber 123 is formed, and an air passage 126 is formed by a connected case 126. In this configuration, combustion air is distributed between three air passages 126 by a fan 124. The fuel is supplied to the vaporizing chamber 122 and the mixing chamber 123 through the fuel pipe 120, while the fuel is supplied into the bot 121 through the fuel pipe 120. The fuel vaporized in the vaporization chamber 122.

- Promote evaporation of fuel by forming a diffusion flame a in the evil vaporization chamber 122 (-1 The remainder enters the mixing chamber 123 and heating chamber 118.
In the mixing chamber 123, the air and vaporized fuel are remixed to form a premixed carbon-containing carbon in the heating chamber 118, and the vaporized fuel passing through this is further thermally decomposed to form a diffusion #IC above it. 0 In such a combustion device, vaporized fuel and air are mixed in stages to form a flame, resulting in stable combustion75; and even if the air flow rate changes, the flame lengths of a, b, and c change. However, since flame C is a diffusion flame, the surrounding oxygen is supplied by molecular diffusion, so the flame elongates, and therefore the combustion chamber cannot be made smaller. .

As explained above, in these conventional combustion devices, it has not been possible to simultaneously reduce the size of the combustion device by shortening the flame and expand the permissible variation range of the air flow required for combustion control.

The present invention eliminates all of these conventional drawbacks, and achieves miniaturization of the combustion device by shortening the flame, simplification of combustion control by expanding the permissible variation range of the air flow rate, and expansion of the combustion rate variable range (hereinafter referred to as TDR). The whole purpose is to achieve this goal. L. In order to achieve this objective, the present invention provides auxiliary air chambers on both sides of a burner port formed by arranging a large number of burner ports, and provides air in the vicinity of the burner port almost parallel to the air-fuel mixture flowing out from the burner port. An auxiliary air port configured to eject air is provided in communication with the auxiliary air chamber, and air chambers are provided on both sides of the burner port on the downstream side of the burner port.

An air port is provided in communication with the air chamber so as to inject air at an angle with respect to the direction in which the air-fuel mixture is ejected. Due to this configuration, the air flow from the auxiliary air ports of both tll11 of the flame port is at a low speed and is equal to the air mixture flow. 1, it does not disturb the flame base that is formed, further increases the stability of the flame with a large -order air ratio, and even with a low flame, a sufficient amount of air is supplied at a low speed to ensure sufficient diffusion and mixing. Small flames are formed near the flame opening as flame holding, which increases the stability of the flame base and leads to the stabilization of the entire flame.Furthermore, on the downstream side, a high-speed inclined air jet forces the diffusion flame to form. atmosphere. Since the supply and forced mixing are performed, the combustion reaction is promoted and the flame is shortened. Also, since the high-speed air flow is ejected at an angle to the downstream side, it does not disturb the flame base on the upstream side.

Embodiment of the present invention] (This will be explained below based on FIGS. 1 to 4.) In FIGS. 1 to 3, 1 is a fan that supplies combustion air, and the outlet has an opening area. Dividing plate 2 for dividing air into three types of secondary air and one type of primary air according to the ratio
f: Connected to the burner body 3 via. On the upstream side of the dividing plate 2, there is provided a fuel pipe 6 with a control valve 4 in the middle, and a nozzle 6 at the tip thereof. The burner body 3 has a symmetrical molded body 7 and a passage inserted in the center. Consists of spikes.

The molded body 7 includes a flame port 1o consisting of a large number of slit-shaped flame ports 9 on both sides, an auxiliary air chamber 12 equipped with a large number of auxiliary air ports 11 near the flame port, and a flame port 1o downstream of the flame port 1°. An air chamber 16 having a number of air ports 14 on its inclined surface is provided on the side, and the auxiliary air chamber 12 and the air chamber 16 communicate with each other through the throttle port 16 .

On the other hand, the two passages 8 are provided with a mixture chamber 17 partitioned by a partition wall, an air chamber 19 having a constriction part 18 at its tip, and an auxiliary air chamber 21 communicating with the constriction part through a constriction port 20 on both sides of the constriction part.

The passage body 8 is inserted into the molded body T, and gaps 26 are formed on both sides of the passage body 80.

Note that the passage body 8 is supported by the molded body 7 from both sides via the flame port 10 by a stepped portion provided on the outer wall of the auxiliary air chamber 21. A combustion chamber 26 is connected to the downstream side of the burner body 3, and a heat exchanger 27 having a large number of fins, an exhaust hood 28, and an exhaust port 29 are connected to the downstream side of the combustion chamber 26. Also, the combustion chamber 26
A water pipe 30 is provided on a part of the outer wall of the tank, and is connected to a heat exchanger 2.

Next, to explain the effect of the above configuration, the combustion air supplied by the fan 1 is supplied into the mixing chamber 17 of the passage body 8 by the one-part plate 2.
With secondary air supplied within 9.

The secondary air is divided into secondary air supplied into the left and right air chambers 16 of the molded body 7. On the other hand, the fuel is set at a predetermined flow rate by the control valve 4, is injected and supplied from the nozzle 6 at the tip through the fuel pipe 5, and enters the mixing chamber 17 together with the secondary air. Inside the mixing chamber 17, the air and fuel flow through the passage body 8 while mixing.
The air-fuel mixture flows from the outlet ports 24 on both sides to the gap 26,
Furthermore, while passing through the gap 26, it is uniformly distributed, heads toward the flame port 1o, and flows out from the flame port 9 into the combustion chamber 26. Air chamber 19
Part of the secondary air that has entered the chamber is appropriately controlled in flow rate by the throttle port 20, flows into the auxiliary air chamber 20, is further decelerated, and flows out at low speed from the auxiliary air port 23 to the vicinity of the flame port 9. It diffuses and mixes with the air-fuel mixture, forming a stable small flame A at the end of the flame port 9 as shown in FIG.

Most of the remaining part increases the flow velocity in the throttle part 18 and is injected and supplied from the air port 22 toward the flame B formed on both sides in a downstream direction, and is forcibly mixed to promote the combustion reaction. Similarly, some of the secondary air that has entered the air chambers 16 on both sides of the molded body 7 enters the auxiliary air chamber 12 at the throttle opening 16°. It flows out to the auxiliary air port and is used for flame stabilization, and most of the remaining air flows to the air port 1.
4 is used to inject at higher speeds and shorten the flame length. The combustion exhaust gas that has completed combustion releases heat from the inside of the combustion chamber 26 in a heat exchanger, is collected in an exhaust hood, and is discharged to the outside through an exhaust port 29. The combustion chamber wall is cooled by a water pipe 3o.

1° The flame thus formed on the two flame ports 10 has a high combustion speed when the primary air ratio is high due to the low-velocity air supplied from the auxiliary air ports 11 and 23, as shown in FIG. The primary flame C, which itself is stable, is made more stable,
Further, when the secondary air ratio is low, stable primary flames C do not exist, but stable small flames A that are diffused and mixed are formed at both ends of the flame port 9, achieving a flame-holding function. Therefore, a stable flame can be obtained over a wide range of primary air ratios.
FIG. 4 shows a comparison between the conventional device and the conventional device. 6th
In the case of the conventional example shown in the figure, when the primary air ratio becomes low, since there is no small flame for flame stabilization, the combustion performance shown by Go, 02 decreases at the low primary air ratio. It shows characteristics like curve e.

On the other hand, in the conventional example shown in Fig. 6, the stability of the flame with respect to the primary air, that is, the fan air volume, is good, but there is no mechanism to create a high-speed secondary air jet, so if the flame grows and the combustion chamber is made smaller. Touching cooling parts such as heat exchangers and causing incomplete combustion. Therefore, the combustion performance in the same combustion chamber condition is as shown by curve m. As described above, in the present invention, better combustion performance can be obtained over a wider range of primary air ratios than in conventional combustion devices. Furthermore, air is forcibly supplied into the diffusion flame B by a high-speed air jet of a large amount of secondary air inclined in the downstream direction supplied from the air ports 14 and 22;
Since the combustion reaction is promoted by forced mixing at the same time, the flame length is shortened and the flame is supplied at an angle in the downstream direction, so even if the flow velocity increases, it often disturbs the upstream flame. .

Similarly, FIG. 4 shows a comparison of this with a conventional device as shown in FIG. Compared to conventional combustion performance, on the side where the secondary air ejection speed is high, there is no effect on the flame base due to the inclined jet, and on the low side, air is supplied to one flame from both sides, so the value at which the flame length starts to grow is smaller. By doing so, it is possible to obtain good combustion performance over a wider range of secondary air ejection speeds. .

As is clear from the following explanation, the combustion apparatus of the present invention provides the following effects.

(1) A small amount of low-velocity air flow supplied from the auxiliary air port increases the stability of the primary flame more when the negative air ratio is high, and by diffusion mixing when the negative air ratio is low. Because it has a flame-holding structure with a small flame, a stable flame can be obtained over a wide range of negative air ratios, and the high-speed jet for shortening the flame is also inclined downstream, so it does not disturb the flame base. 3° (2) The amount of air supplied from the auxiliary air port allows small flames to be distributed only at the end of the flame port. Once formed, it can have a sufficient flame-holding function, so only a small amount is required, and since the amount of air supplied from the air port is large and at high speed, it is forced into the diffusion flame and promotes the combustion reaction by forced mixing. Since the flame becomes shorter, the combustion chamber can be made smaller, and the combustion device can be made smaller.

(3) Since it is possible to maintain a stable flame over a wide range of primary air ratios, the secondary air ratio can be set low, and the residence time in the high temperature range is shortened due to the short flame, resulting in less NO40 generation. Vibratory combustion can be prevented by setting the primary air ratio low.

(4) Since air is supplied from both sides of the flame port, a shorter flame can be achieved even at a lower secondary air ejection speed.
Therefore, a small, quiet fan with low blowing pressure can be used.

[Brief explanation of the drawing]

Fig. 1 is an overall sectional view of a combustion device showing an embodiment of the present invention, Fig. 2 is a sectional perspective view showing the main parts of Fig. 1, and Fig. 3 shows the form of flame formed by the same device. Sectional view shown, No. 4
The figures are for comparing and explaining the combustion performance with the conventional one. A is a characteristic diagram showing the characteristics with respect to the primary air ratio, the opening is a characteristic diagram showing the characteristics with respect to the secondary air ejection velocity, and Figure 6 is the conventional example. The t-side view of FIG. 6 is a sectional view of another conventional example. 9...flame mouth, 1o...flame mouth part, 12,
21... Auxiliary air chamber, 11.23... Auxiliary air port, 1, 19... Air chamber -14, 22
...Air vent. Name of proxy embedding Patent attorney Toshio Nakao and 1 other cylinder 1 Figure 2 Figure 3 Figure 4 Primary air ratio FAI%)

Claims (1)

[Claims] Equipped with auxiliary air chambers on both sides of the flame port where many flame ports are lined up,
An auxiliary air port configured to blow out air substantially parallel to the air-fuel mixture flowing out from the burner port is provided in the vicinity of the burner port, and is connected to the air chamber, and an auxiliary air port is provided on the downstream side of the burner port portion to communicate with the air chamber. Air chambers are provided on both sides of the flame port, and the air ports are provided in communication with the air chamber so as to inject air at an angle with respect to the direction in which the air-fuel mixture is ejected, and the air ejection speed of the auxiliary air port and the air A combustion device in which the flow rate is smaller than the air jet speed and air volume of the air port.