JPH0740819Y2 - Combustion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a combustion apparatus in which a combustion gas is circulated through a mixing pipe provided in front of a spray nozzle to gasify and combust a mixture of air and fuel. It is about.

[Conventional technology]

A heat exchange device 2 using the combustion device 1 shown in FIGS. 4 to 6 is disclosed in Japanese Patent Publication No. 1-24963, which is a prior application of the present applicant. The heat exchanging device 2 is installed with the combustion device 1 facing the inside of a cylindrical combustion chamber 4 provided in the lower portion of the can body 3. In the combustion apparatus 1, a spray nozzle 6 is attached inside a blower pipe 5 for combustion air, and a jet plate 9 having jet holes 7 and 8 for fuel and air is attached to a tip opening portion. ing. In front of the blower pipe 5, a mixing pipe 11 is attached to form a circulation gas inlet 10 for combustion gas. Further, inside the mixing tube 11, a flame holding cylinder 12 and a sub flame holding cylinder 13 and a flame holding plate 14 arranged in the flame holding cylinder 12 are mounted.

The fuel particles ejected from the spray nozzle 6 are mixed with fresh air ejected from the blower pipe 5. Then, this air-fuel mixture is warmed and further atomized or gasified by the combustion gas sucked from the circulation inlet 10. The combustion flame is held by the flame holding plate 14 and spreads and burns throughout the flame holding cylinder 12.

[Problems to be solved by the device]

Thus, recently, there is a tendency to downsize the entire heat exchange device 2. This is to make the whole compact by reducing the diameter of the can 3 in particular. However, if the can body 3 is made smaller in this way, the volume of the combustion chamber 4 decreases, and the pressure in the combustion chamber 4 increases when the same combustion device 1 is used. Therefore, set the jet air pressure high,
It was necessary to burn at high load.

However, if the fuel is burned under a high load, there are problems as described below, and it is not possible to meet the demand for downsizing. One of the problems is CO in exhaust gas
This means that the concentration will increase. The cause cannot be clarified because complicated elements are intertwined with each other, but the main cause is that the mixture of fuel particles, fresh air, and circulating gas ejected at high speed comes into contact with the auxiliary flame stabilizing tube 13 and its inner surface side. It is considered that a vortex flow is generated in the fuel cell, and the vortex flow causes non-uniform mixing of the fuel particles, fresh air, and circulating combustion gas. Another problem is that the combustion flame is difficult to stabilize due to the high pressure in the combustion chamber 4, and oscillating combustion is likely to occur. Yet another drawback is that as the temperature decreases, the viscosity of the fuel increases and the air density tends to increase, but the changes in the two are not proportional and as a result, the air / fuel ratio changes. Therefore, under such conditions, when the combustion device 1 is used, stable combustion cannot be performed, and there is a drawback that combustion becomes impossible immediately. That is, there is a drawback that the width in which stable combustion is possible becomes small.

[Means for Solving the Problems]

SUMMARY OF THE INVENTION The present invention has been made by improving and removing the above problem in view of the conventional problems described above, and an object of the present invention is to provide a combustion device having a wide range of stable combustion while achieving the demand for compactness.

Thus, the means adopted by the present invention to solve the above-mentioned problems are as follows: a blower tube for combustion air whose tip opening is positioned toward the combustion chamber; and a liquid arranged inside the blower tube. A spray nozzle for fuel, a jet plate equipped with jet holes for air and fuel and attached to a tip opening of the blower pipe, and a circulation gas inlet for combustion gas are connected to the tip opening of the blower pipe. A mixing tube, a flame holding cylinder mounted in the mixing tube, a flame holding plate attached to the center of the flame holding cylinder, and an annular auxiliary flame holding plate attached to the outer peripheral side of the flame holding cylinder. The combustion device is characterized by the above.

[Action]

The combustion flame is held by the flame holding plate inside the flame holding cylinder and the sub flame holding plate on the outer peripheral side of the flame holding cylinder. Therefore, the area of the combustion flame expands to the outer peripheral side of the flame holding cylinder as compared with the conventional case by the amount held by the auxiliary flame holding plate. Therefore, the combustion flame is stable, unstable combustion does not occur even if the amount of combustion oil fluctuates during high-load operation, and it is possible to reduce the CO concentration and suppress the generation of soot. .

〔Example〕

The structure of the present invention will be described below with reference to the embodiments shown in the drawings.

1 to 3 relate to an embodiment of the present invention, and FIG. 1 is a side view of a semi-longitudinal section showing the whole combustion apparatus 21,
FIG. 2 is a front view of the same, and FIG. 3 is a longitudinal sectional view showing a heat exchange device 22 in which a combustion device 21 is installed. As shown in FIG. 3, in the heat exchange device 22 of this embodiment, the diameter of the can body 23 is extremely small and the whole is made compact. Of course, the volume of the combustion chamber 24 is much smaller than the volume of the combustion chamber 4 of the heat exchange device 2 previously filed by the applicant of the present invention shown in FIGS. 4 and 5. In FIG. 3, 25 is a smoke pipe, 26 is a baffle plate arranged in the smoke pipe 25, and 27 is an exhaust stack.

As shown in FIGS. 1 and 2, the combustion device 21 includes a blower pipe 28.
It has a fuel spray nozzle 29 and an electrode rod 30 for igniting a mixture of fuel and fresh air. Also a blast pipe
A jet plate 31 for fuel and air is integrally formed at the tip opening of 28. The ejection plate 31 includes a central ejection hole 32 for ejecting fuel and fresh air at the same time, a high-speed air ejection hole 33 having a plurality of annular air holes around the central ejection hole 32, and a plurality of annular air holes between the holes 32 and 33. An air jet small hole 34 for preventing the generation of a vortex is provided. In the air ejection small holes 34, in an excessive air supply state, a high speed air flow ejected from the central ejection hole 32 and the high speed air ejection hole 33 causes a negative pressure due to a vortex between the ejection holes 32 and 33. However, the swirl flow draws in the combustion flame, which is to prevent this. In other words, by ejecting air from the middle of the ejection holes 32 and 33, it is possible to prevent the region from becoming negative pressure.

In front of the blower pipe 28, a cylindrical mixing pipe 36 is attached at a predetermined distance from the blower pipe 28 in order to form a circulation inlet 35 for the combustion gas in an annular shape. And mixing tube
A taper cone-shaped flame holding cylinder 37 is attached to the center of the tip of 36. Inside the flame holding cylinder 37, a flame holding plate 38 which is a disc-shaped punching metal is provided. Further, on the outer peripheral side of the flame holding cylinder 37, a sub flame holding plate 39 which is punching metal is provided. This sub flame holding plate 39 has a vertical surface portion 39.
It has a and a horizontal plane portion 39b, and the horizontal plane portion 39b is arranged on the same axis as the high-speed air ejection hole 33.

Next, the operation mode of the apparatus configured as described above will be described. Therefore, what should be noted here is that the size of the can body 23 of the heat exchange device 22 of the present embodiment is extremely small due to the demand for compactness, and the volume of the combustion chamber 24 is also small. Therefore, the pressure in the combustion chamber during combustion is high,
It means that the blowing pressure of fresh air is also set higher than in the conventional case.

In such a combustion device 21, the fuel particles injected from the spray nozzle 29 are first ignited by the spark of the electrode rod 30, and at the beginning, yellow flame combustion starts near the tip of the ejection plate 31. In this state, the air is excessive. afterwards,
The combustion flame gradually moves in the spray direction, and the flame holding plate 38 of the flame holding cylinder 37
And reaches the sub flame holding plate 39 on the outer circumference of the flame holding cylinder 37. In the mixing pipe 36 on the way, the combustion flame is rectified. Then, the combustion flame is stabilized by the flame holding plate 38 and the sub flame holding plate 39, and steady combustion is maintained. As described above, in the present embodiment, the combustion flame burns while being held by the flame holding plate 38 and the sub flame holding plate 39. Therefore, the area of the combustion flame is expanded as compared with the conventional case by the amount held by the auxiliary flame holding plate 39, and extremely stable combustion is performed.

In the steady operation state, the combustion gas is sucked from the circulation inlet 35 and mixed into the mixture of fuel particles and fresh air. Therefore, the fuel particles and the fresh air are warmed, the fuel particles are further atomized or gasified, and blue flame combustion is obtained. That is, the fuel particles, fresh air, and circulating combustion gas are rectified after being mixed in the mixing pipe 36, and what was burned with excess air is close to the theoretical air ratio, and the rectified ideal combustion is achieved. Become. That is, the combustion gas is recirculated,
Since it burns again, low NO _x can be realized.

Then, when combustion is performed in a state where the combustion pressure in the combustion chamber is high,
In general, slight fluctuations in the blast pressure of fresh air and the amount of combustion oil cause the combustion flame to vibrate, resulting in yellow flame combustion, high CO concentration, and even a large amount of soot. is there. However, in the combustion device 21 of the present embodiment, as described above, the combustion flame is held by both the flame holding plate 38 and the sub flame holding plate 39, and since the area is greatly expanded, it is extremely It is possible to obtain stable combustion. Therefore, in the present device 21, oscillating combustion is less likely to occur even if there is some variation in the blast pressure or the amount of combustion oil. That is,
It is possible to increase the region width between the lower limit and the upper limit at which stable combustion can be maintained.

[Effect of device]

As described above, in the present invention, the combustion flame can be held by both the flame holding plate inside the flame holding cylinder and the sub flame holding plate around the outer circumference of the flame holding cylinder to expand the area of the combustion flame. it can. for that reason,
Even if the volume of the combustion chamber is small and the combustion pressure is high, it becomes difficult for oscillating combustion to occur, and it is possible to realize a compact heat exchange device and the like. Further, since the conventional auxiliary flame holding cylinder can be omitted, it is possible to reduce the CO concentration.

[Brief description of drawings]

1 to 3 relate to an embodiment of the present invention. FIG. 1 is a side view of a semi-longitudinal section of a combustion apparatus, FIG. 2 is a front view thereof, and FIG. The vertical cross-sectional views of the heat exchange device, and FIGS. 4 to 6 relate to the prior art filed by the applicant of the present invention. FIG. 4 is a vertical cross-sectional view of the heat exchange device, and FIG. FIG. 6 is a partial cross-sectional perspective view of the combustion device. 21 ... Combustor, 24 ... Combustion chamber 29 ... Spray nozzle, 28 ... Blower pipe 31 ... Jet plate, 32 to 34 ... Jet holes 35 ... Circulation inlet, 36 ... Mixing pipe 37 ... Flame holding cylinder, 38 …… Flame holding plate 39 …… Sub flame holding plate

Claims (1)

[Scope of utility model registration request] 1. A blower tube for combustion air whose tip opening is positioned toward the combustion chamber, a spray nozzle for liquid fuel disposed inside the blower tube, and an ejection hole for air and fuel. An ejection plate attached to the tip opening of the blower tube, a mixing tube connected by forming a combustion gas circulation inlet at the tip opening of the blower tube, and a flame holding tube attached to the mixing tube And a flame holding plate attached to the central portion of the flame holding cylinder, and an annular auxiliary flame holding plate attached to the outer peripheral side of the flame holding cylinder.