JPH11351570A - Pilot burner having burnout preventive structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect the forward end of a pilot burner from burning out by the heat of main flame. SOLUTION: A main gas pipe 2 and a pilot fuel gas pipe 3 are disposed in a heat chamber 1 passing combustion air and combustion air is fed through the heat chamber to the burner tip side when a flame is generated. A pilot flame is generated on the burner tip side by injecting pilot fuel gas from a pilot fuel gas injection hole 5 made at the forward end of the pilot fuel gas pipe 3 and a main flame is generated on the burner tip side by injecting main fuel gas from a main fuel gas injection hole 4 made at the forward end of the main fuel gas pipe 2. In such a burner, a small purging hole 7 is made in the side face of the pilot fuel gas pipe at a part in the heat chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pilot burner having a burnout prevention structure.

[0002]

2. Description of the Related Art A main fuel gas pipe for passing a main fuel gas and a pilot fuel gas pipe for passing a pilot fuel gas are provided in a combustion cylinder for passing combustion air sent from a blower. A pilot burner that injects pilot fuel gas from the pilot fuel gas injection hole provided in the pilot fuel gas pipe to generate a pilot flame at the tip side, and a main fuel gas injection hole provided at the tip of the main fuel gas pipe through the main fuel gas injection hole There is a main burner that generates a main flame on the tip side of the main fuel gas pipe by injecting a fuel gas, and a pilot burner and a main burner are provided close to each other to shift the flame. In the case of the burner, when combustion is performed by the main burner, the supply of fuel gas to the pilot burner is stopped and the pilot flame is extinguished, but the pilot burner is provided near the flame generating portion of the main burner. Therefore, there is a problem that the tip of the pilot burner may be heated by the heat of the main flame, and the tip of the pilot burner may be burned.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to prevent the tip of the pilot burner from being burned out by the heat of the main flame.

[0004]

A main fuel gas pipe and a pilot fuel gas pipe are provided in a combustion cylinder through which combustion air passes, and when a flame is to be generated, the combustion air is passed through the combustion cylinder through a burner tip. Side, and injects pilot fuel gas from the pilot fuel gas injection hole provided at the tip of the pilot fuel gas pipe to generate a pilot flame at the pilot burner tip side, and the main fuel gas injection hole provided at the tip of the main fuel gas pipe In a burner in which a main flame is generated on the tip side of the main burner by injecting more main fuel gas, a purging small hole is provided on a side surface of the pilot fuel gas pipe in a portion inside the combustion cylinder.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partial sectional side view of a burner embodying the present invention. The burner is a cylindrical combustion cylinder 1 through which combustion air sent from a blower (not shown) is passed.
Is provided with a main fuel gas pipe 2 having a concentric circle smaller in diameter than the combustion cylinder 1. The main fuel gas pipe 2 has a baffle plate 6 at the front end, a main fuel gas injection hole 4 at the front end further than the baffle plate 6, and a main fuel gas inlet at the other end. The part becomes the main burner. A pilot fuel gas pipe 3 is provided in the combustion cylinder 1 in parallel with the main fuel gas pipe 2. Is provided with a pilot fuel gas inlet, and the pilot fuel gas pipe 3 serves as a pilot burner.

The pilot fuel gas pipe 3 has a baffle plate 6
Two purging holes 7 are provided on the side of the pilot fuel gas pipe corresponding to the inner portion of the combustion cylinder 1 closer to the base. The purging small hole 7 is a hole penetrating the wall surface of the pilot fuel gas pipe 3. The pilot fuel gas is not sent into the pilot fuel gas pipe 3, and the fuel air is sent into the combustion cylinder 1. In such a case, the combustion air in the combustion cylinder 1 is made to enter the pilot fuel gas pipe 3 through the purge small hole 7.

When the burner is to be burned, first, a pilot flame is generated by the pilot burner, the main burner is ignited by the pilot flame, and the combustion of the main flame is started. FIG. 2 is a cross-sectional view of a tip portion of the pilot fuel gas pipe 3 for combustion when a pilot fuel gas is supplied into the pilot fuel gas pipe 3 and a pilot flame is generated at the front end of the pilot fuel gas pipe 3. It shows the flow of air. When the pilot fuel gas is sent into the pilot fuel gas pipe 3, the pressure of the combustion air is set so that the pressure of the combustion air at the purging small hole 7 and the pressure of the pilot fuel gas become substantially the same. The supply pressure and the supply pressure of the pilot fuel gas are set in advance. By setting the pressures of the combustion air and the pilot fuel gas at substantially the same pressure, the pilot fuel gas flows out of the pilot fuel gas pipe 3 through the purge holes 7 during the pilot flame combustion, or the combustion air flows through the pilot fuel gas. The gas is prevented from flowing into the gas pipe 3 and the combustion air and the pilot fuel gas are prevented from being mixed before the pilot fuel gas injection hole 5.

The main fuel gas is supplied to the main fuel gas pipe 2 in a state where the pilot flame is generated, and the main fuel gas is injected from the main fuel gas injection hole 4 so that the pilot flame is generated by the main fuel gas injection hole. The process moves to the main fuel gas being injected from 4, and the combustion by the main flame is started. Since the pilot flame for igniting the main flame is unnecessary during the combustion of the main flame, the supply of the pilot fuel gas is stopped after the ignition of the main flame, and the pilot flame is extinguished. .
FIG. 3 is a cross-sectional view of the tip portion of the pilot fuel gas pipe 3 and shows the flow of combustion air when the pilot fuel gas is not supplied into the pilot fuel gas pipe 3. If the pilot fuel gas is not sent into the pilot fuel gas pipe 3, the pressure in the pilot fuel gas pipe 3 becomes low, and the pressure of the combustion air near the purge hole and the pressure in the pilot fuel gas pipe 3 are reduced. Because of the difference,
Combustion air flows into the pilot fuel gas pipe 3 from the purging small holes 7. The combustion air flowing into the pilot fuel gas pipe 3 is sent through the pilot fuel gas pipe 3 and is injected from the pilot fuel gas injection holes 5. When the combustion of the main burner is started, the heat of the main flame reaches the tip of the pilot fuel gas pipe 3. By injecting combustion air from the pilot fuel gas injection hole 5, the tip of the pilot fuel gas pipe 3 To be cooled,
The pilot fuel gas pipe 3 is not overheated, and burning of the pilot fuel gas pipe 3 is prevented.

[0009]

According to the present invention, the tip of the pilot burner is prevented from being overheated by the heat of the main flame, so that the tip of the pilot burner can be prevented from burning.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view of a burner according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a flow of combustion air when supplying pilot fuel gas in one embodiment of the present invention.

FIG. 3 is a diagram illustrating the flow of combustion air when the supply of pilot fuel gas is stopped according to one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 combustion cylinder 2 main fuel gas pipe 3 pilot fuel gas pipe 4 main fuel gas injection hole 5 pilot fuel gas injection hole 6 baffle plate 7 purging small hole

Claims (2)

[Claims] 1. A main fuel gas pipe and a pilot fuel gas pipe are provided in a combustion cylinder through which combustion air sent from a blower passes, and when a flame is generated, the combustion air is passed through the combustion cylinder. The pilot fuel gas is sent to the burner tip side, and pilot fuel gas is injected from the pilot fuel gas injection hole provided at the tip of the pilot fuel gas pipe to generate a pilot flame at the pilot burner tip side, and the main fuel gas provided at the tip of the main fuel gas pipe In a burner in which a main flame is generated at a tip side of a main burner by injecting a main fuel gas from an injection hole, a small hole for purging is provided on a side wall of a pilot fuel gas pipe in an inner portion of a combustion cylinder. Pilot burner with. 2. A pilot burner having a burnout prevention structure according to claim 1, wherein a pressure of the pilot fuel gas sent through the pilot fuel gas pipe during the combustion of the pilot burner and a combustion gas sent around the purging small hole. A pilot burner having a burnout prevention structure, wherein a supply pressure of a pilot fuel gas and a supply pressure of combustion air are set so that air pressures are substantially equal.