JPH06180108A - Combustion process for surface combustion burner and surface combustion burner - Google Patents

Abstract

PURPOSE:To prevent a casing from being deformed by feeding cooling air into the casing during combustion by the burner and improve the heat efficiency using air heated by cooling the easing. CONSTITUTION:In the t' burner wherein a porous member 11 comprising a combustion surface, a easing 13 extending from the vicinity of its periphery toward the rear, a mixed gas chamber 110 formed of them, an opening 41 for feeding a burnt gas mixture A into the mixed gas chamber 40 and a cooling chamber 20 formed in the easing 13 are provided, and the cooling chamber 20 has an air inlet part 21 and an air outlet part 22 which is allowed to communicate with a burnt gas-mixing chamber 50 through a gas feed pipe 62, the easing 13 is cooled by cooling air B from the air inlet part 21 and the cooling air B heated thereby is used as the air for forming the burnt gas mixture A fed into the mixed gas chamber 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface combustion burner, and more particularly, to a casing of a burner provided with an air cooling layer and supplying cooling air to the air cooling layer so that the casing is deformed by heating by combustion. The present invention relates to a surface-combustion burner which is designed to prevent

[0002]

2. Description of the Related Art Conventionally, for example, a planar porous member made of, for example, a ceramic having pores which are sufficiently communicated with each other on the front and back sides so that the combustion gas mixture diffuses, and the combustion gas mixture is supplied to the back surface thereof. A surface combustion burner is known in which the mixture reaches the front surface of the planar porous member while diffusing and is ignited and burned in the vicinity of the front surface. This type of surface combustion burner heats the flat porous member to incandescent,
Most of the energy is released as radiant heat, and the thermal conductivity of porous materials such as ceramics is usually small, and even if the combustion temperature on the front surface is raised considerably, the temperature on the back surface does not rise so much so that flashback occurs. It is used in a wide range of fields, not limited to household combustion equipment, as a safe burner that can prevent the generation of heat and has high thermal efficiency.

The basic structure of the surface combustion burner will be described with reference to FIG. 3. In the surface combustion burner shown in FIG. 3, the planar porous member 11 having a rectangular or circular shape has a heat resistant packing 12 interposed therebetween. Mounted on the front side of the tubular casing 13. The front end of the casing 13 is bent inward toward the inside in an L-shape to form a flange 14, and the flange 14 positions the porous member 11 in the front direction.

The planar porous member 1 inside the casing 13
A spacer 15 made of an annular member having a U-shaped cross-sectional shape is arranged on the back surface of 1. The shape of the outer peripheral portion of the spacer 15 is the same as the shape of the inner peripheral wall portion of the casing 13, and the spacer 15 is press-fitted into the casing 13 from the rear side so that the back surface of the planar porous member 11 is the front surface thereof and the flange 14 of the casing. It is supported while being pressed against.

The spacer 15 is supported by a back plate 16 having the same shape as the inner peripheral wall portion of the casing 13. The outer peripheral edge portion of the back plate 16 constitutes a bent portion 17, and the front end of the bent portion 17 and the rear end portion of the casing 13 are welded together 30 along the entire circumference thereof, so that the casing 13 and the plane perforation are formed. With the quality member 11 and the back plate 16,
A mixed gas chamber 40, which is one closed space, is formed. A cylindrical tube 18 is fixed to the central portion of the back plate 16 by an appropriate means, and the combustion gas mixture A is supplied to the mixed gas chamber 40 from the cylindrical tube 18.

The combustion of this surface combustion burner is carried out as follows. Combustion gas mixture A from an appropriate gas source is press-fitted into the mixed gas chamber 40 through the cylindrical tube 18. The injected combustion gas mixture A passes from the back surface of the flat porous member 11 through the continuous pores to reach the front surface, where it is ignited and burned. The flat porous member 1 due to the combustion
The front surface of No. 1 becomes incandescent and emits radiant heat.

[0007]

The surface combustion burner as described above is extremely effective from the viewpoint of effective utilization of heat and safety. However, when the surface combustion burner is burned, the portion of the burner casing 13 is heated by the heat of the high temperature exhaust draft or the like to reach a high temperature, which may cause the casing 13 itself to be deformed. When the casing 13 of the surface combustion burner is deformed in this way, a gap is created at the joint between the casing 13 and the planar porous member 11, combustion gas leaks from the gap and a blue flame appears, and the radiation conversion efficiency decreases. At the same time, there arises a problem that the emission amount of nitrogen oxides also increases.

As a means for solving the problem, as shown in FIG. 4, an air chamber 20 is provided so as to surround the mixed gas chamber 40, and the cooling air B is fed from the air supply pipe 60 to the air chamber 20. Air is discharged from the air outlet portion 22 on the upper surface of the chamber 20 toward the outer peripheral edge portion of the planar porous member 11 as indicated by an arrow, or as shown in FIG. Cooling air B is supplied from the air supply pipe 60 to the air chamber 20, and the cooling air heated along the holding plate 19 from the air outlet portion 22 formed in the front surface of the air chamber 20. It is conventionally known that B is discharged to the outside to prevent the portion of the casing 13 from being heated to a high temperature by cooling with the cooling air B. (Jitsuko 61-33386 gazette, Jitsukaihei 3-12
However, in all of these cases, the supplied cooling air is eventually discharged to the outside, and the fact is that this is not always effectively utilized.

An object of the present invention is to eliminate the above-mentioned disadvantages of the conventional surface combustion burner. More specifically, in the method of burning a surface combustion burner, cooling air is supplied during combustion of the burner. By continuously feeding the casing, it is prevented that the casing is heated to a high temperature and is deformed, and the cooling air heated by cooling the casing is collected and supplied to the mixed gas chamber. The purpose of the invention is to achieve an improvement in thermal efficiency by utilizing it as air for forming a body, and further, the present invention provides a surface combustion burner capable of reliably and easily carrying out such a combustion method. That is also the purpose.

[0010]

In order to solve the above-mentioned problems and to achieve the object, the present invention has a porous member forming a combustion surface on the front surface, and extends from the vicinity of the outer periphery of the porous member toward the rear surface. In a combustion method of a surface combustion burner having an existing casing, a mixed gas chamber formed of the porous member and the casing, and an opening for supplying a combustion gas mixture to the mixed gas chamber, Air cooling layer is provided,
Cooling air is fed to the air cooling layer to cool the casing heated by combustion, and the cooling air heated by cooling the casing is recovered and supplied to the mixed gas chamber. A method for burning a surface combustion burner is provided, which is used as air for forming a combustion gas mixture.

Further, in order to reliably and easily carry out the above combustion method, the present invention comprises a porous member having a combustion surface on the front surface, and a casing extending from the vicinity of the outer periphery of the porous member toward the rear surface. A surface combustion burner having a mixed gas chamber formed of the porous member and a casing, an opening for supplying a combustion gas mixture to the mixed gas chamber, and a cooling chamber formed in the casing, The cooling chamber has an air inlet portion and an air outlet portion, and the air outlet portion is in communication with an opening for supplying a combustion gas mixture to the mixed gas chamber,
Provide a surface combustion burner.

In such a surface combustion burner, the casing is formed by an inner frame for holding the porous member and an outer frame having an air inlet portion and an air outlet portion, and the inner frame and the outer frame. A cooling chamber can be easily formed in the casing by providing a cooling chamber between the combustion gas and the combustion gas that communicates with the opening of the mixed gas chamber on the upstream side of the flow of the combustion gas mixture. A mixing chamber is provided, the fuel gas inlet is opened in the combustion gas mixing chamber, and the combustion gas mixing chamber and the air outlet of the cooling chamber are connected by an air supply pipe to heat the casing by cooling. The collected cooling air and the formation of the combustion gas mixture can be easily performed.

The porous member is usually made of iron, chromium,
It is extremely effective to use a sintered body of long fibers made of an alloy such as silicon, aluminum or yttrium.

[0014]

The combustion of the surface combustion burner of the present invention is carried out as follows. Fuel gas is supplied from a suitable fuel gas supply device into the supply path of the combustion gas mixture that leads to the mixed gas chamber of the burner, and cooling air serves as an air cooling layer from the air inlet portion of the casing. It is discharged from the air outlet through the inside of the cooling chamber, and is discharged into the supply passage of the combustion gas mixture leading to the mixed gas chamber without being diffused to the outside. Then, the fuel gas fed into the supply passage of the combustion gas mixture and the cooling air are mixed, and the mixture is sent under pressure as a combustion gas mixture into the mixed gas chamber. The combustion gas mixture that has entered the mixed gas chamber then passes through the porous member that is the combustion surface, reaches the surface thereof, and is ignited and burned. The combustion heats the casing, but the cooling air continuously fed into the cooling chamber of the casing cools the casing so that the temperature does not exceed a certain level. Then, the cooling air whose temperature has been raised by cooling the casing is continuously fed, as air for forming the combustion gas mixture, into the supply path of the combustion gas mixture which leads to the gas mixture chamber. .

Therefore, during combustion, the temperature of the casing does not become so high as to be deformed due to the temperature change, and the cooling air whose temperature is raised by cooling the casing is used as the combustion gas mixture. , The thermal efficiency of burner combustion is improved.

[0016]

The present invention will be described in more detail based on the description of one embodiment. FIG. 1 is a perspective view of an embodiment of a surface combustion burner according to the present invention, and FIG. 2 is a sectional view thereof.
In this surface combustion burner 10, except for the structure of the casing 13 and the structure for supplying the combustion gas mixture A to the mixed gas chamber 40, the other structures are the same as those shown in FIG. The detailed description will be omitted by attaching.

In this embodiment, the casing 13 is
Inner frame 131 for holding the porous member 11
And an outer frame 132 having an air inlet portion 21 and an air outlet portion 22, and the cooling chamber 20 is formed between the inner frame 131 and the outer frame 132. The cooling chamber 20 forms an air layer composed of a continuous space so as to surround the outside of the inner frame 131 of the casing 13, and has an air inlet portion 21 and an air outlet portion 22 at substantially opposite positions thereof. Except for the air inlet portion 21 and the air outlet portion 22, a sealed space portion is formed. The air inlet portion 21 is connected to a blower for cooling air (not shown) via a blower pipe 60, and the air outlet portion 22 is connected to a cylindrical pipe 18 as described later.
The combustion gas mixing chamber 50 formed inside the
Through the.

Regarding the portion for supplying the combustion gas mixture A to the mixed gas chamber 40, a cylindrical tube 18 fixed to the central portion of the back plate 16 by an appropriate means is provided with one end of which an opening of the mixed gas chamber 40 is provided. It is configured to communicate with 41 and close the other end, and a combustion gas mixing chamber 50 is formed therein. A fuel gas inlet portion 51 and an air inlet portion 52 are opened on the side wall of the cylindrical tube 18, and the fuel gas inlet portion 51 is a fuel gas supply device and a fuel gas supply pipe (not shown). Connected via 61,
The air inlet portion 52 communicates with the air outlet portion 22 of the cooling chamber 20 of the casing 13 via the air supply pipe 62.

An embodiment of the combustion method for the surface combustion burner of the present invention will be described with reference to the surface combustion burner 10 described above.
The cooling air B is fed to the cooling chamber 20 from the air inlet portion 21 of the casing 13 by a blower (not shown) via the blower pipe 60, and after forming an air layer for cooling in the cooling chamber 20. The air is discharged from the air outlet portion 22 and is fed to the combustion gas mixing chamber 50 in the cylindrical pipe 18 via the air feeding pipe 62. Then, in the combustion gas mixing chamber 50, the fuel gas C sent from a fuel gas supply device (not shown) via the fuel gas supply pipe 61 and the air B sent from the cooling chamber 20 are mixed. Then, the combustion gas mixture A is formed, and the mixture is pressed into the mixed gas chamber 40 through the opening 41. The combustion gas mixture injected into the mixed gas chamber 40 passes from the back surface of the planar porous member 11 through the continuous pores to reach the front surface, where it is ignited and burned. Due to the combustion, the front surface of the planar porous member 11 becomes incandescent, and radiant heat is emitted. When such combustion continues, the casing 13 is heated by the combustion, but the cooling air B is continuously fed from the air inlet portion 21 to the cooling chamber 20 in the casing 13 by the blower through the blower pipe 60. Therefore, the casing 13 is cooled and does not reach a high temperature that causes deformation. The cooling air B, which has become hot due to the cooling of the casing 13, passes from the air outlet 22 through the air supply pipe 62 to the combustion gas mixing chamber 5
0, all of which is recovered and used as air for forming the combustion gas mixture A. In this case, since the air has a high temperature due to the cooling of the casing 3, a high-temperature combustion gas mixture is formed, and the thermal efficiency of combustion is improved.

There are many other variations of the surface burner of the present invention. In the above embodiment, the casing 1
3, the cooling chamber 20 can be easily formed inside the casing 3, and the casing 13 has an inner frame 131 for holding the porous member 11, and an outer frame 132 having an air inlet portion 21 and an air outlet portion 22. The structure of the casing itself is 2
It does not need to be composed of members. Further, for example, in a case where the cooling chamber is not provided inside the casing itself as shown in FIG. 3, another member having a cooling chamber having an independent structure is attached to the outer peripheral portion of the casing (in that case, Many embodiments can be adopted, such as a combination of the casing and the separate member).

[0021]

The combustion method of the surface combustion burner according to the present invention can prevent the casing from being heated to a high temperature and deformed during combustion of the burner, so that the radiation conversion efficiency is reduced and nitrogen oxides are reduced due to the appearance of the blue flame. In addition to not causing an increase in the discharge amount of air, it is also possible to improve the thermal efficiency by collecting and using the cooling air that has been heated to a high temperature by cooling the casing and uses it. There is a special effect that you can.

Furthermore, the surface-burning burner according to the invention makes it possible to carry out such a combustion method reliably and easily.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a surface combustion burner according to the present invention.

2 is a cross-sectional view of the surface combustion burner shown in FIG.

FIG. 3 is a sectional view showing a basic conventional example.

FIG. 4 is a sectional view showing another conventional example.

FIG. 5 is a cross-sectional view showing another conventional example.

[Explanation of symbols]

 10-Surface combustion burner 11-Porous member 13-Casing 131-Inner frame 132-Outer frame 20-Cooling chamber 21-Air inlet 22-Air outlet 40-Mixed gas chamber 41-Opening 50-Combustion gas mixing chamber 62 -Air line

Claims (4)

[Claims] 1. A porous member having a combustion surface on its front surface,
A casing extending from the vicinity of the outer periphery of the porous member in the rear surface direction, a mixed gas chamber formed by the porous member and the casing, and an opening for supplying a combustion gas mixture to the mixed gas chamber. In the combustion method for a surface combustion burner, the casing is provided with an air cooling layer, and cooling air is supplied to the air cooling layer to cool the casing heated by combustion and to heat the casing by cooling it. A combustion method for a surface combustion burner, characterized in that the cooled cooling air is recovered and used as air for forming a combustion gas mixture to be supplied to a mixed gas chamber. 2. A porous member having a combustion surface on its front surface,
A casing extending from the vicinity of the outer periphery of the porous member in the rear surface direction, a mixed gas chamber formed by the porous member and the casing, and an opening for supplying a combustion gas mixture to the mixed gas chamber, A surface combustion burner having a cooling chamber formed in the casing, the cooling chamber comprising:
A surface combustion burner having an air inlet portion and an air outlet portion, the air outlet portion being in communication with an opening for supplying a combustion gas mixture to a gas mixture chamber. 3. The casing comprises an inner frame for holding a porous member and an outer frame having an air inlet portion and an air outlet portion, and a cooling chamber is provided between the inner frame and the outer frame. The surface combustion burner according to claim 2, wherein the surface combustion burner is formed. 4. A combustion gas mixing chamber communicating with the opening is provided upstream of the opening of the mixing gas chamber into which the combustion gas mixture flows, and a fuel gas inlet is opened in the combustion gas mixing chamber. At the same time, the surface combustion burner according to claim 2, wherein the combustion gas mixing chamber and the air outlet portion of the cooling chamber are connected by an air supply pipe.