JPS62162823A - Pulse combustion device - Google Patents

Abstract

PURPOSE:To reduce nitrogen oxide concentration without particularly changing carbon monoxide concentration in exhaust gas, by a method wherein cross- sections of a combustion chamber and a tail pipe, coupled to the combustion chamber, are formed in the shape of an oval or a rectangle, both having length in a longitudinal different from that in a lateral direction. CONSTITUTION:The cross-sections of a combustion chamber 14 and a pair of branch pipe parts 16, with which a tail pipe 15 is formed, are formed in the shape of, for example, an oval having length in a longitudinal direction different from that in a lateral direction, and the combustion chamber 14 and the branch pipe parts 16 are installed in a manner that their longitudinal directions are extended in a vertical direction. This constitution enables increase of a heat transfer area of each of the combustion chamber 14 and the tail pipe 15 compared with that available when they are formed in the shape of a circle in cross section. Thereby, nitrogen oxide concentration can be reduced without particularly changing carbon monoxide concentration. A relation between a length L1 of the combustion chamber 14 and a length L2 of each of a pair of the branch pipe parts 16, with which the tail pipe 15 is formed, is set to L1/L2<0.5, and oscillation of a pulse can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pulse combustion apparatus with an improved combustion chamber and tail pipe.

[Technical background of the invention and its problems]

Fig. 5 shows a schematic configuration of the main parts of the pulse combustion device. 1 is a combustion chamber for pulse combustion, 2 is a tail pipe connected to the downstream side of this combustion chamber 1, and 3 is an upstream side of the combustion chamber 1. Mixture connected to the side! It is. An air supply pipe 4 and a fuel supply pipe (not shown) are connected to the mixing chamber 3, respectively. Further, an air chamber 5 is connected to the air supply pipe 4. Inside the air chamber 5, an air flapper valve 6 and a starting fan are installed. Furthermore, an air suction pipe 7 is connected to the outer surface of the air chamber 5.

Further, a fuel flapper valve is interposed in the fuel supply pipe.

At the time of startup, a starting fan is driven to supply air sucked into the air chamber 5 through the air suction pipe 7 to the mixing chamber 3 side via the air flapper valve 6 and the air supply pipe 4, and the air and fuel are The mixture with the fuel gas supplied through the supply pipe is ignited by a spark plug 8 for initial ignition attached to the peripheral wall surface of the mixed seedling 3, causing explosive combustion within the combustion chamber 1. Moreover, the pressure within the combustion chamber 1 rises rapidly due to this explosive combustion. Therefore, combustion chamber 1
As the pressure within the combustion chamber 1 increases, the air flapper valve 6 and the fuel flapper valve close, stopping the supply of air and fuel gas, and the combustion gas within the combustion chamber 1 rapidly expands toward the tail pipe 2. It flows out to the side at high speed. Also,
The pressure in the combustion chamber 1 rapidly decreases to negative pressure due to the inertial force when this combustion gas flows out from the combustion chamber 1 to the tail pipe 2 side at high speed. Therefore, this negative pressure opens the air flapper valve 6 and the fuel flapper valve, so that air and fuel gas flow into the mixing chamber 3 again.

Then, the mixture of air and fuel gas explodes and burns again in the combustion chamber 1 due to contact with the combustion gas at a temperature remaining in the combustion chamber 1, and from then on, the mixture of air and fuel gas is ignited in a constant cycle by the same action. The explosion and combustion of the fuel is repeated in a pulsed manner.

By the way, in the conventional pulse combustion device, the combustion v1 and the tail pipe 2 are formed by cylinders with circular cross-sections, so the temperature near the center axis of the combustion chamber 1 and the tail pipe 2 is easily maintained at a high temperature. There was a problem. Therefore, there is a problem in that NOx (nitrogen oxides) is likely to be generated in the combustion gas, and the concentration of NOx (nitrogen oxides) in the exhaust gas is likely to increase.

In this case, if the temperature in the vicinity of the central axes of the combustion chamber 1 and tail pipe 2 is extremely reduced, there is a risk that co (-carbon oxide) will be generated in the combustion gas. Therefore, when trying to reduce the NOx (nitrogen oxide) concentration, Co(-
If the Co (-carbon oxide) concentration increases and an attempt is made to lower the Co (-carbon oxide) S degree, NOx (nitrogen oxide)
There was a tendency for S degree to increase.

[Purpose of the invention]

An object of the present invention is to provide a pulse combustion device that can reduce the NOx (nitrogen oxide) concentration without significantly changing the Co (-carbon oxide) concentration in exhaust gas.

[Summary of the invention]

The present invention is characterized in that the cross-sectional shape of the combustion chamber and the tail pipe connected to the combustion chamber is formed into an elliptical or rectangular shape with different widths in the vertical and horizontal directions.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. FIG. 1 shows a schematic configuration of the main parts of a pulse combustion device used as a heat source for a liquid heating device such as a boiler device, and 11 is the main body of the liquid heating device. This liquid heating! 1 main body 11 is provided with an outer box 12 and an inner box 13, respectively.

The inner box 13 forms a liquid tank for storing liquid.

Moreover, inside the inner box 13, a combustion engine 14 of a pulse combustion device is installed.
and a tail pipe 15 are respectively provided. in this case,
The combustion chamber 14 of the pulse combustion device is disposed approximately at the center of the inner box 13, as shown in FIG. Further, the tail pipe 15 is formed by a pair of branch pipe portions 16.16 disposed on both sides of the combustion W14. And combustion chamber 1
Each introduction end side of the branch pipe section 16.16 is connected to the downstream side of the branch pipe section 4.

Furthermore, as shown in FIG. 2, a relatively wide accommodation space 17 is formed between the outer box 12 and the inner box 13 on one side of the liquid heating device main body 11. In this accommodation space 17 there is combustion.
A mixing chamber 18 connected to the upstream side of J14 and a large tubular tube 19 connected to each outlet end side of the branch pipe section 16.16.
are arranged respectively. Roughly speaking, an air supply pipe 20 and a fuel supply pipe 21 are connected to the mixing chamber 18, respectively. Further, an air chamber 22 attached to the outer surface of the outer box 12 is connected to the air supply pipe 20. This air chamber 22
An air flapper valve 23 and a starting fan (not shown) are installed inside each. Further, an air suction pipe 24 is connected to the outer surface of the air chamber 22. Further, the fuel supply pipe 21 is provided with a fuel flapper valve 25 and other components. Furthermore, a spark plug 26 for starting and ignition is attached to the peripheral wall surface of the mixing chamber 18.

On the other hand, the cross-sectional shape of the pair of branch pipe portions 16.16 forming the combustion chamber 14 and the tail pipe 15 is formed into an elliptical shape with different widths in the vertical and horizontal directions, as shown in FIG.

In this case, the ratio of the length and width of the ellipse of the combustion chamber 14I3 and the branch pipe portion 16.16 is set to about 3:2 or more. These combustion chambers 14 and branch pipe portions 16
．． 16 are installed with their longitudinal directions facing up and down. In addition, the length L1 of the combustion chamber 14 and the length L of the pair of branch pipe portions 16.16 forming the tail pipe 15 are also included.
2 is Ll/L2 <0. I have it set to 5.

Next, the operation of the above configuration will be explained. First, when starting up the pulse combustion device, a starting fan is driven, and the air sucked into the air chamber 22 through the air suction pipe 24 is mixed through the air flapper valve 23 and the air supply pipe 20.
A mixture of this air and fuel gas supplied through the fuel supply pipe 21 is ignited by the starting ignition spark plug 26 attached to the peripheral wall of the mixture 18, and the mixture is ignited into the combustion chamber 14. It explodes and burns. Moreover, the pressure within the combustion chamber 14 rises rapidly due to this explosive combustion.

Therefore, as the pressure in the combustion v14 increases, the air flapper valve 23 and the fuel flapper valve 25 close,
As the supply of air and fuel gas is stopped, combustion gas in the combustion chamber 14 rapidly expands toward the pair of branch pipe sections 16. The water flows into each branch pipe section 16.16 at a high velocity in a state where the flow is divided into two directions. And the combustion chamber 14
The combustion gas that has flowed into each of the branch pipe sections 16 and 16 is caused to flow into the same large double tube 19 through each of the branch pipes 8I116 and 16, and is discharged from this large double tube 19 to the outside via an exhaust pipe (not shown). There is.

Further, this combustion gas is transferred from the combustion chamber 14 to each branch pipe section 16.
Combustion v1 due to inertial force when flowing out to the 16 side at high speed
The pressure inside 4 suddenly decreases to negative pressure. Therefore, this negative pressure opens the air flapper valve 23 and the fuel flapper valve 25, so that air and fuel gas flow into the mixture v18 again. Then, the mixture of air and fuel gas explodes and burns again in the combustion chamber 14 due to contact with the high-temperature combustion gas remaining in the combustion chamber 14, and thereafter the mixture explodes in a constant cycle due to the same action. The combustion is repeated in pulses.

During this pulse combustion, the combustion chamber 14 is heated to a high temperature due to explosive combustion of the mixture of air and fuel gas, and the tail pipe 15 is heated by the flow of high-temperature combustion gas flowing out from the combustion chamber 14. The pair of branch pipe portions 16, 16 and the decoupler 19 forming the combustion chamber 141 are heated to a high temperature state, and the combustion chamber 141 and the branch pipe portions 16, 16. The liquid in the liquid tank of the inner box 13 is heated by the heat from the large tube 19. In this case, the cross-sectional shape of the pair of branch pipe parts 16.16 forming the combustion chamber 14 and the tail pipe 15 is formed into an elliptical shape with different lengths in the vertical direction and the horizontal direction, so that the combustion chamber 14 and the branch pipe part 16 Because each of the combustion chambers 14 was installed with its longitudinal direction facing up and down, the combustion chamber 14
Also, the heat transfer area of the tail pipe 15 can be increased.

Therefore, as shown in FIG.
) p with! I[ttAA= (Co)N / (Co
) p is maintained at a substantially constant state regardless of the state of change in the combustion amount ratio Y Y=QN/Qp between the combustion lQN of the pulse combustion device according to the embodiment of the present invention and the combustion m Q p of the conventional pulse combustion device. On the other hand, the concentration ratio of NOx11 degrees (NOX)N in the exhaust gas of the pulse combustion device of this known example to NoxF1 degree (NOx) p in the exhaust gas of the conventional pulse combustion device B B = (NOx)N/(NOx)p can be reduced by about 0.25 to 0.5 as the combustion amount ratio Y changes. Therefore, NOx (nitrogen 11'll! oxide) il1 degree can be reduced without significantly changing C0 (-carbon oxide) a degree. In addition, 1 burning seedling
Since the heat transfer efficiency can be improved by increasing the heat transfer area of 4 and the tail pipe 15, it is also possible to downsize the entire device.

In addition, since the relationship between the length Ll of the combustion chamber 14 and the length L2 of the pair of branch pipe portions 16.16 forming the tail pipe 15 is set to Ll /L2 <0.5, the pulse oscillation is Stabilization can be achieved.

Furthermore, since the tail pipe 15 of the pulse combustion device is formed by a pair of branch pipe sections 16 and 16 disposed on both sides of the combustion chamber 14, the pulse combustion device can be used as a heating source for a liquid heating device such as a boiler device. When used, the temperature distribution within the liquid tank formed by the inner box 13 can be made uniform, and efficiency can be improved.

Note that this invention is not limited to the above embodiments. For example, the number of branch pipe portions 16 in which the tail pipe 15 is formed may be three or more. Further, the cross-sectional shape of the combustion v14 and the tail pipe 15 connected to the combustion chamber 14 may be formed into a rectangular shape with different lengths in the vertical direction and the horizontal direction. Of course, other modifications can be made without departing from the gist of the present invention.

(Effects of the Invention) According to the present invention, the cross-sectional shape of the combustion chamber and the tail pipe connected to the combustion chamber is formed into an elliptical shape or a rectangular shape with different lengths in the vertical direction and the horizontal direction. Go (
- carbon oxide) concentration without significantly changing the NOx concentration.
(Nitrogen oxides) can be reduced by 11 degrees.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention.
Figure 1 is a vertical sectional view showing the schematic configuration of the main parts of a pulse combustion device installed in a liquid heating tank, Figure 2 is a sectional view taken along the line ■-■ in Figure 1, and Figure 3 is Cross-sectional view along the ■-■ line in Figure 1,
FIG. 4 shows the NOx concentration ratio and c in exhaust gas between a pulse combustion device according to an embodiment of the present invention and a conventional pulse combustion device. Characteristic diagram showing the relationship between concentration ratio and combustion ratio, 5th
The figure is a longitudinal cross-sectional view of the main parts of a conventional example. 14... Combustion chamber, 15... Tail pipe, 16... Branch pipe section. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (3)

[Claims] (1) A pulse combustion device characterized in that a combustion chamber and a tail pipe connected to the combustion chamber have an elliptical or rectangular cross-sectional shape with different lengths in the vertical and horizontal directions. (2) The combustion chamber has its length L_1 and the tail pipe length L
The pulse combustion apparatus according to claim (1), wherein the relationship with L_2 is set to L_1/L_2<0.5. (3) The pulse combustion device according to claim (1), wherein the tail pipe is formed by a plurality of branch pipe sections connected to the combustion chamber.