JP2019174015A - Surface combustion burner - Google Patents

Abstract

To provide a surface combustion burner having a burner element in which a circumference of a metallic porous plate is covered by heat resistant metal fiber knitted item to perform combustion by injecting pre-mixed gas to an outside surface of heat resistant metal fiber knitted item to enable occurrence of oscillatory burning to be restricted by improving combustion stability.SOLUTION: There is provided a surface combustion burner having a cylindrical processed metallic porous plate 4, a burner head 2 composed of heat resistant metallic fiber knitted item 5 covering an outer surface of a cylindrical metallic porous plate, in which pre-mixed gas having combustion air and fuel gas pre-mixed to each other is supplied into a cylinder formed by the metallic porous plate, and the pre-mixed gas passes through said metallic porous plate and heat-resistant metallic fiber knitted item and is ignited at the outside surface of the heat-resistant metallic fiber knitted item. Said metallic porous plate 5 has an opening ratio at a part near a root side of the burner head 2 that is larger than an opening ratio at a part corresponding to an extremity end side of the burner head.SELECTED DRAWING: Figure 1

Description

The present invention supplies a premixed gas mixed with combustion air and fuel gas from a metal porous plate side to a burner head having a burner element in which a heat-resistant metal fiber knitted fabric and a metal porous plate are integrally laminated. The invention relates to a surface combustion burner that burns on the outer surface of the heat-resistant metal fiber knitted fabric by injecting a premixed gas to the outside of the heat-resistant metal fiber knitted fabric, more specifically, improving the flame combustion stability, The present invention relates to a surface combustion burner capable of preventing the occurrence of vibration combustion.

As described in JP 2001-235117 A, a burner head having a burner element in which a heat-resistant metal fiber knitted fabric (metal knit) and a metal perforated plate (punching metal) are integrally laminated, There is known a surface combustion burner that supplies a premixed gas in which fuel gas is premixed and injects the premixed gas through a hole in a metal perforated plate and a knitted layer made of heat-resistant metal fibers to burn on the surface of the knitted fabric made of heat-resistant metal fibers. ing. In the surface combustion burner described in Japanese Patent Application Laid-Open No. 2001-235117, a flat heat-resistant metal fiber knitted fabric is welded to a flat metal porous plate, and the heat-resistant metal fiber knitted fabric is welded from the metal porous plate side. A premixed gas is injected to the outer surface side, and combustion is performed near the outer surface of the knitted fabric made of heat-resistant metal fibers.

Further, in the burner described in JP-A-2001-235117, a water tube group is installed in a rectangular parallelepiped space and burns from one side surface of the water tube group. The burner element made of a metal perforated plate is shaped like a flat plate, but it is used for boilers in which a water pipe is arranged in an annular shape so as to surround the combustion chamber provided in the center and the burner is installed in the center of the combustion chamber In this case, a surface combustion burner having a structure in which a metal porous plate is processed into a cylindrical shape and a knitted fabric made of a heat-resistant metal fiber is attached to the peripheral portion of the cylindrical metal porous plate is also used.

In the case of such a surface combustion burner, since the flame burns on a wide surface, the flame can be short, and the combustion chamber can be made small, so there is also an advantage that the apparatus can be miniaturized. . However, the disadvantage is that the flame is widely dispersed, so that the combustion tends to become unstable, and vibration combustion tends to occur when combustion is performed on the high air ratio side. Therefore, it has been desired to improve the stability of combustion.

JP 2001-235117 A

A problem to be solved by the present invention is a surface having a burner element in which a metal perforated plate is covered with a heat-resistant metal fiber knitted fabric and injecting a premixed gas onto the outer surface of the heat-resistant metal fiber knitted material for combustion An object of the present invention is to provide a surface combustion burner capable of improving the stability of combustion and suppressing the occurrence of vibration combustion in the combustion burner.

The invention described in claim 1 has a burner head made of a metal perforated plate processed into a cylindrical shape and a heat-resistant metal fiber knitted fabric covering the outer surface of the cylindrical metal perforated plate, and is formed of a metal perforated plate The premixed gas in which the combustion air and the fuel gas are premixed is supplied into the cylinder, and the premixed gas is made of the heat-resistant metal fiber through the metal perforated plate and the heat-resistant heat-resistant metal fiber knitted fabric. In the surface combustion burner designed to burn on the outer surface of the knitted fabric, the metal porous plate has a larger opening ratio in the portion near the base side of the burner head than in the portion corresponding to the tip side of the burner head. It is characterized by that.

According to a second aspect of the present invention, in the surface combustion burner, in the cylinder formed by the metal porous plate, a wind direction adjustment for guiding a premixed gas flow flowing inside the cylinder toward the surrounding metal porous plate A board is installed.

If the aperture ratio of the metal porous plate is increased on the root side of the burner head and decreased on the tip side, the amount of premixed gas that goes out of the heat-resistant metal fiber knitted fabric from the root side with a large aperture ratio increases, The amount of premixed gas that goes out of the knitted fabric made of heat-resistant metal fibers from the tip side having a small aperture ratio decreases. In addition, in the cylinder formed by the metal perforated plate, if a wind direction adjusting plate for guiding the premixed gas flow flowing inside the cylinder toward the surrounding metal perforated plate is installed, the heat resistance from the base side of the burner head The amount of premixed gas that goes out of the metal fiber knitted fabric increases, and the amount of premixed gas that goes out of the heat resistant metal fiber knitted fabric from the tip side having a small aperture ratio decreases. If the premixed gas that permeates the combustion surface of the burner increases on the upstream side of the burner combustion surface, the flame on the upstream side of the burner combustion surface increases, and the combustion of the flame is stabilized. Due to the flame being held, the combustion on the entire combustion surface is stabilized, and the occurrence of vibration combustion can be prevented.

By implementing the present invention, it is possible to stabilize the combustion of the flame and suppress the occurrence of vibration combustion.

The partial cross-sectional perspective view which cut off some knitted layers made from a heat-resistant metal fiber in the surface combustion burner which is implementing this invention The partial cross-sectional perspective view cut | disconnected by the metal porous board part in the surface combustion burner which is implementing this invention Flow diagram of the entire surface combustion burner implementing the present invention

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partially sectional perspective view of a knitted layer made of a heat-resistant metal fiber in a surface combustion burner embodying the present invention, and FIG. 2 is a diagram showing a metal made in a surface combustion burner embodying the present invention. FIG. 3 is a flow diagram of the entire surface combustion burner implementing the present invention.

The surface combustion burner of the present invention mixes combustion air and fuel gas in the burner duct by injecting fuel gas into the burner duct 1 through which combustion air flows, and sends the premixed gas to the burner head 2. The burner duct 1 is a pipe having a large diameter for flowing combustion air sent from the blower 9. In the middle of the burner duct 1, a venturi pipe 3 for reducing the flow passage area in the burner duct is installed, and a fuel gas pipe 8 for supplying fuel gas is connected to a place where the venturi pipe 3 is installed.

The combustion air sent from the blower through the burner duct 1 flows along the inner surface of the venturi tube 3, and the flow passage cross-sectional area through which the combustion air flows through the venturi tube 3 decreases. Will increase. The flow passage cross-sectional area of the combustion air suddenly expands beyond the tip of the venturi tube 3 and spreads outward, so that the combustion air flow spreads from the portion beyond the tip of the venturi tube 3 to the end.

In the portion of the combustion air flow that spreads from the tip of the venturi tube 3, the pressure is lowered, so that entrainment from the surroundings occurs, and the action of drawing the fuel gas flow supplied from the fuel gas pipe 8 occurs. Therefore, mixing of combustion air and fuel gas is promoted.

The premixed gas in which the combustion air and the fuel gas are mixed is sent to the burner head 2 at the tip of the burner duct 1 and burns at the burner head 2 portion. The burner head 2 has a cylindrical burner element, and the premixed gas that has passed through the burner duct 1 enters the inside of the cylindrical burner head, passes through the cylindrical burner element, and ejects the premixed gas in the circumferential direction. To do.

The burner element of the burner head 2 installed downstream of the burner duct 1 is formed by processing a punching metal 4 which is a metal perforated plate into a cylindrical shape and covering the periphery thereof with a metal knit 5 which is a heat-resistant metal fiber knitted fabric. It is said. In the punching metal 4, the diameter of the hole is made different between a portion corresponding to the base side of the burner head 2 and a portion corresponding to the tip side. If the hole pitch is the same and the hole diameter is increased on the burner head base side, the opening ratio of the punching metal 4 increases on the base side of the burner head and decreases on the tip side.

Further, in a cylindrical space formed inside the cylindrical punching metal, a pre-expanded wind direction adjusting plate 7 for guiding the premixed gas flow flowing inside the cylinder toward the cylinder wall surface is installed. The wind direction adjusting plate adds a circumferential element to the flow of the premixed gas flowing downward from above in FIG. 2, and the conical air direction adjusting plate is concentric with the cylindrical punching metal. Provided. The air direction adjusting plate 7 is provided in a relatively upstream portion in the burner head, and the flow direction of the premixed gas changed by the air direction adjusting plate 7 is a portion in which the opening of the punching metal on the burner head base side is enlarged. Keep on going.

In the punching metal 4 in which a large number of holes are formed in the metal plate, the premixed gas can be passed through the hole portions, and the premixed gas cannot be passed through the portions other than the holes. The metal knit 5 that covers the outside of the punching metal 4 allows the premixed gas to permeate as a whole, but the amount of premixed gas that is fed into the metal knit layer increases at the portion where the opening ratio of the punching metal is large. In the portion where the rate is small, the amount of premixed gas fed into the metal knit layer is reduced.

Further, the wind direction adjusting plate allows more premixed gas to flow in the circumferential direction on the upstream side of the burner head, so that the amount of premixed gas that permeates the metal knit layer on the upstream side of the burner head increases. .

A pilot burner 6 for generating a pilot flame is installed in the burning part of the burner head, and premixed gas is injected from the inside of the punching metal to the outside of the metal knit layer while the pilot flame is burned by the pilot burner 6. Then, the flame is burned near the outer surface of the metal knit layer.

The amount of the premixed gas sent to the burner head 2 passes through the metal knit layer in the portion near the base of the burner head 2 and the amount passing through the metal knit layer in the portion near the tip of the burner head 2 is Less than the root side. Therefore, the combustion in the burner head 2 is performed in a wide range of the burner head surface because a firm flame is generated in a portion where a large amount of the premixed gas is injected, and this flame that performs stable combustion exists. Since the flame is also stable, it is possible to suppress the occurrence of vibration combustion due to unstable combustion.

The present invention is not limited to the embodiments described above, and many modifications can be made by those having ordinary knowledge in the art within the technical idea of the present invention. For example, in the embodiment, the wind direction adjusting plate 7 has a conical shape. However, this may be a conical shape with a widening, and the punching metal has the same diameter and the hole pitch is increased on the upstream side. You may do it.

1 Burner duct
2 Burner head 3 Venturi tube 4 Metal perforated plate (punching metal)
5 Heat-resistant metal fiber knitted fabric (metal knit)
6 Pilot burner 7 Wind direction adjusting plate
8 Fuel gas piping 9 Blower

Claims (2)

Combustion air and fuel into a cylinder made of a metal porous plate with a burner head made of a metal porous plate processed into a cylindrical shape and a heat-resistant metal fiber knitted fabric covering the outer surface of the cylindrical metal porous plate A premixed gas in which gas is premixed is supplied, and the premixed gas is allowed to permeate the metal perforated plate and the heat-resistant heat-resistant metal fiber knitted fabric and burn on the outer surface of the heat-resistant metal fiber knitted fabric. In the surface combustion burner
The surface-burning burner is characterized in that the metal porous plate has an aperture ratio in a portion near the base side of the burner head larger than an aperture ratio in a portion on the tip side of the burner head. The surface combustion burner according to claim 1, wherein a wind direction adjusting plate for guiding a premixed gas flow flowing inside the cylinder toward a surrounding metal porous plate is installed in the cylinder formed by the metal porous plate. A surface combustion burner characterized in that

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