JP3331384B2 - Gas burner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas burner used in a combustor such as a boiler, a water heater and a water heater, and capable of reducing the generation of NOx.

[0002]

2. Description of the Related Art In recent years, there has been a demand for reducing the generation of NOx in gas burners used in various fields such as boilers, water heaters and water heaters, and low NOx gas burners of various structures have been proposed. (For example, Japanese Utility Model Laid-Open No. 2-741
No. 4 gazette).

[0003]

The low NOx gas burner of this type is installed in a combustion furnace such as a boiler or a heat exchanger, in order to adjust the heat output and match the furnace.
The adjustment of the gas pressure to be supplied and the air volume of the blower are performed. However, due to the adjustment of the gas pressure and the air volume, the generation amount of NOx varies depending on the installed combustion furnace and the like, and the generation amount of NOx is constantly controlled. There is a problem that it is difficult to effectively reduce it.

The present invention has been made in view of the above points, and effectively reduces the generation of NOx irrespective of the structure of an object to be heated such as a combustion furnace equipped with a gas burner, the pressure in the furnace, and the like. It is an object to provide a gas burner which can be used.

[0005]

In order to achieve the above object, a gas burner according to the present invention comprises a draft tube to which a blower is connected and which feeds combustion air, and a donut-shaped burner head provided on an outer peripheral portion and an inner peripheral portion. An air flow path is provided, a pilot burner is provided in the space inside the burner head, and a plurality of main
Holes inclined outward to the center axis of the burner head.
And a plurality of sub-devices near the inner surface of the burner head.
A gas hole is provided, and a position adjusting mechanism for adjusting the positions of the tip of the burner head and the pilot burner with respect to the tip of the draft tube is provided.

[0006]

[Operation / Effect] In the gas burner having such a configuration, when the draft tube is connected to the furnace, the position of the gas supply pipe is adjusted according to the pressure in the furnace in order to reduce the amount of NOx and CO generated. The mechanism adjusts the distance between the tip of the draft tube and the tip of the burner head. This distance is adjusted to increase as the internal pressure of the furnace decreases, and to decrease as the internal pressure of the furnace increases.

As described above, by adjusting the distance between the tip of the draft tube and the tip of the burner head, the spread of the flame to the surroundings is changed. Regardless of the structure of the heating element and the pressure in the furnace, the amount of NOx and CO generated can be effectively reduced.

[0008] When igniting, first, the pilot burner is ignited in a state in which the blower starts to blow air into the draft tube, and then gas is ejected from the burner head to transfer the main flame to the burner head. burner
Combustion gas generated from flame generated from main gas hole of head
Is bent inward by the air flow and the ring
The air stream that blows out in the center of the burner head
A negative pressure section is generated in the section. As a result, the fuel
Recirculate so that the burned combustion gas is returned to the center of the nozzle
This combustion gas is reburned by the auxiliary flame from the auxiliary gas.
As a result, the generation of NOx is reduced.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a gas burner used in a boiler or the like, and FIG. 2 is a front view thereof. 1
Is a cylindrical draft tube, a blow box 2 is connected to and connected to the base of the draft tube 1, a blower 3 is connected to a side of the blow box 2, and air blown from the blower 3 is blown by the blow box 2. Through to the draft tube 1.

In the draft tube 1, a donut-shaped burner head 4 is provided with air passages 5 and 6 provided on its outer peripheral portion and inner peripheral portion. That is, a plurality of ribs 4a are protruded from an outer peripheral portion of the donut-shaped burner head 4, and the ribs 4a are brought into contact with the inner surface of the tube 1 to insert the burner head 4 into the tube. An air flow path 5 is formed in the outer peripheral portion of the air passage.

Further, a plurality of main gas holes 4b are formed in the outer peripheral edge of the front surface of the burner head 4 at a specific inclination angle θ (eg, 45 °) inclined outward with respect to the center axis of the burner. A plurality of auxiliary gas holes 4c are provided near the front of the inner surface of the head 4. About 10 to 15 main gas holes 4b are arranged at regular intervals around the nozzle, and the flames generated from the main gas holes do not interfere with each other to form an appropriate dispersing flame, thereby increasing the temperature of the flame. Prevent,
The aim is to reduce NOx.

If the number of the main gas holes 4b is too small, the generation rate of CO tends to increase, which causes a problem. Three to six sub-gas holes 4c are formed at regular intervals on the inner peripheral surface of the burner head 4, and the inner diameter of the sub-gas holes 4c is about 1/2 of the main gas hole. The auxiliary gas holes 4c are provided for stable combustion. However, if the amount of auxiliary gas ejected from the holes becomes excessive, the amount of NOx generated increases, so that the number of auxiliary gas holes 4c is reduced to such an extent that stable combustion is not hindered. Reduce the inner diameter.

Further, a cup-shaped flame holding member 7 having a large number of holes formed in the periphery and the front plate is disposed in the inner space of the donut-shaped burner head 4, and the inside of the burner head 4, that is, the flame holding member. An air flow path 6 flowing through the member 7 is formed.

A pilot burner 10 is disposed in the center of the draft tube 1 and in the space inside the burner head 4 so as to penetrate the flame holding member 7. The pilot burner 10 has a pilot nozzle 12 attached to the tip of a pilot gas supply pipe 11 and an ignition spark rod 1
4, a flame detection rod 13 is provided adjacent thereto.

On the other hand, a gas supply pipe 8 is connected / fixed to the back of the burner head 4, and the gas supply pipe 8 penetrates through the blower box 2 at a position corresponding to the tip of the draft tube 1. 4 is provided with a position adjusting mechanism 19 for adjusting the position of the distal end. This position adjustment mechanism 1
9 is a male thread portion 8a provided on the outer peripheral portion of the gas supply pipe 8.
And nuts 9a and 9b which are screwed into the male screw portion 8a from both inside and outside with the side wall of the blower box 2 interposed therebetween.
The position adjusting mechanism 19 adjusts the distance S between the tip of the draft tube 1 and the tip of the burner head 4.

The gas burner having the above configuration is used as a combustor such as a boiler by connecting the tip of the draft tube 1 to a furnace. When the draft tube 1 is connected to the furnace, the amount of generated NOx and CO is reduced. To reduce the pressure, the distance S between the tip of the draft tube 1 and the tip of the burner head 4 is adjusted by the position adjusting mechanism 19 of the gas supply pipe 8 according to the pressure in the furnace. This distance S is, for example, 1
Adjust to 2mm to -5mm (negative state in which the burner head 4 protrudes from the draft tube 1).
S is increased, and as the furnace internal pressure is increased, S is decreased (negative side).
Adjust to

Even when the burner head 4 is moved and adjusted with respect to the draft tube 1 by the position adjusting mechanism 19, the pilot burner 10 with respect to the burner head 4 can be moved.
Is always the same, and the gas supply pipe 8 is moved and adjusted together with the pilot gas supply pipe 11.

By adjusting the distance S between the tip of the draft tube 1 and the tip of the burner head 4 as described above, the spread of the flame to the surroundings is changed. Regardless of the structure of the object to be heated and the pressure inside the furnace, the amount of NOx and CO generated can be effectively reduced.

When the gas burner is ignited, first, gas is discharged from the pilot nozzle 12 in a state where the blower 3 is started to blow air into the draft tube 1, and the gas is discharged between the ignition spark rod 14 and the flame holding member 7. Generates a spark discharge and ignites the pilot burner 10, and then causes gas to be ejected from the burner head 4.
Let the main flame ignite.

The flame generated from the main gas hole 4b of the burner head 4 is generated so as to spread in the outer circumferential direction of the donut-shaped burner head 4, but the air formed on the inner surface of the draft tube 1 at the outer circumferential portion of the burner head 4 is formed. The air from the blower 3 is blown out in a ring shape through the flow path 5 toward the front of the burner.

For this reason, the main gas holes 4 of the burner head 4
The combustion gas generated from the flame generated by b is bent inward by the air flow, and a negative pressure portion is generated at the center front of the burner head 4 by the air flow ejected in a ring shape. For this reason, the combustion gas ejected from the main gas hole 4b and circulated so as to return to the center of the nozzle, and the combustion gas is reburned by the auxiliary flame from the auxiliary gas hole 4c, thereby generating NOx. Is reduced.

FIGS. 4 and 5 show another embodiment. In this gas burner, instead of the cup-shaped flame holding member 7 of the above-described embodiment, a disk-shaped flame holding member 1 having a large number of holes is formed.
7 is attached to the air passage 6 inside the burner head 4. The flame holding member 17 is attached to the front of the cup-shaped flame holding member 7, and the pilot burner 10 is attached so as to penetrate the flame holding member 17 in the same manner as described above.

In this gas burner, though not shown, a position adjusting mechanism similar to that described above is provided at a fixed position of the gas supply pipe 8, and the position adjusting mechanism and the tip position of the draft tube 1 are connected to the burner. The distance S from the tip of the head 4 is adjusted. The inclination angle θ of the main gas hole 4b of the burner head 4 with respect to the center axis of the burner is also set to a specific angle (for example, 45 °) in the same manner as described above.

[Brief description of the drawings]

FIG. 1 is a sectional view of a gas burner showing one embodiment of the present invention.

FIG. 2 is a front view of the gas burner.

FIG. 3 is a perspective view of a nozzle portion of the gas burner.

FIG. 4 is a sectional view of a nozzle portion of a gas burner according to another embodiment.

FIG. 5 is a perspective view of a nozzle portion of another embodiment.

[Explanation of symbols]

1-draft tube, 3-blower, 4-burner head, 4b-main gas hole, 4c-sub gas hole, 5,6-air flow path, 10-pilot burner, 19-position adjustment mechanism.

Continuing from the front page (72) Inventor Nao Kobayashi 1-1177 Miyamachi, Ginan-cho, Hashima-gun, Gifu Prefecture Kato Iron Works Co., Ltd. Burner Mfg. Inspector Kazumi Kawamukai (56) References JP-A-5-126323 (JP, A) Japanese Utility Model 3-5022 (JP, U) Japanese Utility Model 60-165648 (JP, U) Japanese Utility Model 59-148920 (JP, U) Japanese Utility Model Utility Model 60-181570 (JP, U) (58) (Int.Cl. ⁷ , DB name) F23D 14/84 F23D 14/22

Claims (1)

(57) [Claims] To 1. A blower is connected within the draft tube to send the combustion air, donut-shaped burner head is disposed by providing an air flow path in the inner peripheral portion and the outer peripheral portion, said Banahe
A pilot burner is provided in the space inside the pad, and
A plurality of main gas holes are formed in the outer peripheral edge of the
Pierced to the outside with respect to the center axis of the head, and
A plurality of auxiliary gas holes are located near the inner front of the burner head.
Provided, gas burner, wherein a position adjusting mechanism for adjusting the position of the tip of the burner head and the pilot burner with respect to the distal end position of the draft tube is provided.