JPH10148311A - Gas injection nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a gas injection port from being clogged with adhering dust in a gas injection nozzle capable of accurately feeding a combustion air of which amount corresponds to a low gas injection amount. SOLUTION: A gas injection nozzle 10 has a cylinder part 15 and a base part 11 for closing a base end of the cylinder part 15. The base part 11 is connected to a nozzle block 30 (a gas supplying member) and the extremity end of the cylinder part 15 is fitted into an inlet 21 of a pilot burner 20 without any clearance at all. The cylinder part 15 is provided with an air introducing port 16. The base part 11 has a protrusion 17 arranged within the cylinder part 15. The extremity end 17a of the protrusion 17 is projected toward the burner 20 rather than toward the air introducing port 16. A gas passage 14 passes through the protrusion 17, its extremity end is opened at the extremity end 17a of the protrusion 17 to act as an injection port 14a. Gas is injected from the injection port 14a and then combustion air is fed from the air introducing port 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas injection nozzle for supplying fuel gas to a burner.

[0002]

2. Description of the Related Art A general gas injection nozzle for supplying a fuel gas to a burner is connected to a nozzle block (gas supply member), and a tip end thereof enters an inlet of the burner through an annular gap. . The nozzle has a gas passage extending in the axial direction. The base end of this gas passage is connected to the gas passage of the nozzle block, and the front end opens to the front end of the nozzle to serve as an injection port. In the nozzle, the fuel gas is injected from the injection port toward the inlet of the burner through the gas passage, and the combustion air is drawn into the injection gas so that the combustion air flows through the annular gap between the nozzle tip and the burner inlet. Introduced to.

In the case of using the nozzle having the above-described structure, there is variation in the flow cross-sectional area of the annular gap formed between the burner inlet and the nozzle, so that the amount of introduced air also varies. When used for general burners with a large amount of gas injection,
Although slight variations in the amount of air introduced are not a problem, for example, when the amount of gas injection is small and the amount of combustion air introduced is small accordingly, as in a pilot burner, Optimum combustion cannot be ensured due to variations in the flow cross section.

Therefore, a nozzle as shown in JP-A-1-266413 is used for supplying gas to the pilot burner. This nozzle is fitted without gap into the inlet of the burner. The burner has an air inlet formed near the inlet. Gas injection is performed from the nozzle, and combustion air is introduced from the air inlet of the burner. Since the opening area of the air inlet is accurately determined, the amount of combustion air introduced can be set to an amount corresponding to the gas injection amount.

A nozzle 50 as shown in FIG. 5 has been developed in order to reduce the manufacturing cost as compared with the above-mentioned Japanese Patent Application Laid-Open No. Hei 1-266413. The nozzle 50 has a base portion 51 and a cylindrical tubular portion 55 protruding from the base portion 51. The base portion 51 has a flat plate portion 52 having a hexagonal shape when viewed from the axial direction, and a screw portion 53 provided on the back side thereof. The nozzle 50 is connected to the nozzle block 30 (gas supply member) via a screw portion 53, and the tip of the cylindrical portion 55 is inserted into the inlet 21 of the pilot burner 20 without any gap.

The base portion 51 is provided with a gas passage 54 extending along the axial direction. The distal end of the gas passage 54 opens to the end face of the flat plate portion to form the injection port 54a.
An air inlet 56 is formed in the cylindrical portion 55. Since the air inlet 56 is formed in the nozzle 50, the manufacturing cost is lower than when the air inlet is formed in the pilot burner 20. The fuel gas that has passed through the gas passage 31 of the nozzle block 30 and the gas passage 54 of the nozzle 50
4a, the fuel is injected in the axial direction as shown by the solid arrow, and is drawn into the injected gas, so that the combustion air is introduced from the air inlet 56 as shown by the broken arrow, and the pilot burner 20 To the entrance 21.

[0007]

However, if the nozzle 50 of FIG. 5 is used for a long time, a long cylinder 100 made of dust is formed along the axial direction (gas injection direction) from the periphery of the injection port 54a. However, there has been a defect that gas injection cannot be sufficiently performed due to a pressure loss in the cylinder 100, and gas injection cannot be performed due to closing of the tip of the cylinder 100. The clogging of the injection port 54a is caused by the fact that the injection port 54a is formed to have a small diameter corresponding to a small amount of gas injection,
Since it is introduced from 6 and collides in the cylindrical portion 55 or intersects in a direction orthogonal to the injection gas, it is also considered that a vortex is formed in the vicinity of the injection port 54a. Dust carried along the vortex accumulates to form the cylinder 100.

[0008]

According to a first aspect of the present invention, there is provided a tubular portion which is inserted into the inlet of a burner without a gap, and which is provided so as to close a proximal end side of the tubular portion and is connected to a gas supply member. A gas passage formed in the base, a base end of the gas passage communicating with the gas passage of the gas supply member, and a distal end facing the inside of the cylinder as an injection port. In the gas injection nozzle in which the air inlet is formed in the portion, the base portion has a convex portion arranged in the cylindrical portion, the gas passage passes through the convex portion, and the jetting is performed at the tip of the convex portion. The mouth is open, and the tip of the projection is located at a position protruding in the burner direction from the edge of the air introduction port on the gas supply member side.

According to a second aspect of the present invention, in the gas injection nozzle according to the first aspect, a tip of the convex portion is located at a position protruding in a burner direction from a burner side edge of the air inlet. I do. According to a third aspect of the present invention, in the gas injection nozzle according to the first or second aspect, the base portion includes a flat plate portion closing a base end side of the cylindrical portion, and the cylindrical convex portion protruding from the flat plate portion. And the tip of the projection has a tapered surface. According to a fourth aspect of the present invention, in the gas injection nozzle according to the second aspect, the convex portion has a tapered surface, and the air inlet is radially opposed to the tapered surface. And

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 2, the pilot burner 20 is connected to a nozzle block 30 (gas supply member) via the gas injection nozzle 10. The main burners (not shown) are arranged on both sides of the pilot burner 20 (both sides in the direction perpendicular to the plane of FIG. 1), and are connected to the nozzle block 30 via another gas injection nozzle (not shown). It is connected. The case where the present invention is applied to a hot water supply apparatus will be described as an example.
0, The assembly of the nozzle block 30 is housed in the lower part of the case. A heat exchanger is housed in the upper part of this case.

As shown in FIG. 1, the nozzle 10 has a base portion 11 and a cylindrical portion 15 protruding from the base portion 11. The base portion 11 has a hexagonal shape as viewed from the axial direction, and has a flat plate portion 12 for closing the base end side of the cylindrical portion 15 and a screw portion 13 provided on the back side thereof. The nozzle 10 is connected to the nozzle block 30 by screwing the screw portion 13 into the nozzle block 30. The tip of the cylindrical portion 15 of the nozzle 10 is inserted into the inlet 21 of the pilot burner 20. There is only a slight clearance between the cylindrical part 15 and the inlet 21,
There is substantially no gap between them.

A plurality of, for example, two air inlets 16 are formed at regular intervals in the longitudinal direction of the cylindrical portion 15 at equal intervals to a circumferential doctor. The base portion 11 projects from the flat plate portion 12 and has a columnar convex portion 17 disposed in the cylindrical portion 15.
have. The projection 17 is coaxial with the cylinder 15 and has an outer diameter smaller than the inner diameter of the cylinder 15. The tip 17a of the projection 17 is located at a position protruding in the burner 20 direction from the edge 16a of the air inlet 16 on the burner 20 side. The tip 17a is a plane orthogonal to the axis of the tube portion 15. The outer peripheral surface of the distal end portion of the convex portion 17 forms a tapered tapered surface 17b (conical surface).

The nozzle 10 includes a screw portion 13 and a flat plate portion 1.
2, a gas passage 14 penetrating through the convex portion 17 and extending in the axial direction of the cylindrical portion 15. The base end of the gas passage 14 is open to the end face of the screw portion 13 and communicates with the gas passage 31 of the nozzle block 30, and the front end is opened to the front end 15 a of the convex portion 17 to form an injection port 14 a.

In the above configuration, the fuel gas flows from the gas pipe (not shown) to the gas passage 31 of the nozzle block 30.
Then, through the gas passage 14 of the nozzle 10, the fuel is injected from the injection port 14 a into the cylindrical portion 15 as shown by the solid arrow, and supplied to the inlet 21 of the pilot burner 20. The combustion air is drawn into the gas injection as shown by the dashed arrow, and is
Introduced into the pilot burner 20 together with the fuel gas.
Is supplied to the entrance 21. The fuel gas and the combustion air supplied from the inlet are mixed in an internal passage of the pilot burner 21, and are ejected from a flame port formed at an upper end of the pilot burner 21 to be used for pilot combustion.

The flow of the combustion air in the cylindrical portion 15 will be described in detail. Although the combustion air is introduced in a substantially radial direction from the air inlet 16, it is hindered by the outer peripheral surface of the convex portion 17, and changes its direction in the axial direction together with the suction action by the gas injection, and It heads toward the entrance 21 of the pilot burner 20 along the outer peripheral surface. Therefore, the fuel gas flows toward the pilot burner 21 in synchronization with the flow of the injected fuel gas, and the generation of the vortex near the injection port 14a is suppressed. A part of the combustion air swirls toward the back of the annular gap between the convex portion 16 and the cylindrical portion 15.

The dust introduced together with the combustion air travels toward the peripheral surface of the convex portion 17 where the tip 1
It is divided into those going to 7a and those going to the back. The dust heading backward stays on the eddy of the combustion air. The dust heading toward the tip 17a of the projection 17 together with the combustion air passes near the tip 17a of the projection 17, but as described above, the vortex of the combustion air is suppressed here so that the combustion air follows the injection gas. Therefore, the dust also flows to the pilot burner 20 without staying at the tip 17a of the projection 17 and is burned by the pilot burner 20. As a result, the dust is
Can be prevented from adhering to the tip 17a, and the injection port 14a can be prevented from being blocked by the attached dust. Since the outer periphery of the tip of the projection 17 is a tapered surface 17a, the flow of combustion air is more favorably synchronized with the flow of the injection gas, and the adhesion of dust at the tip 17a of the projection 17 is further improved. It can be assured.

Next, another embodiment of the present invention will be described. In these embodiments, components corresponding to those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In the second embodiment shown in FIG. 3, the protrusion 17 is shorter than in the first embodiment, and the tip 17a of the protrusion 17 is smaller than the edge 14b of the air inlet 14 on the nozzle block 30 side.
Although it is at a position protruding in the 0 direction, it is at a position retracted from the edge 14a of the air inlet 14 on the burner 20 side. Although this embodiment is inferior to the first embodiment, it has an effect of suppressing dust adhesion.

In the third embodiment shown in FIG. 4, a projection 40 having a shape different from that of the above-described embodiment is provided. This convex part 4
0 has a substantially conical shape. That is, the protrusion 40
Has a front end 40a that forms a flat surface orthogonal to the axis, and has a tapered surface 40b that extends from the front end 40a to near the inner periphery of the cylindrical portion 15. When viewed from the radial direction, the air introduction port 16 is arranged to face the tapered surface 40b. That is, the base end of the projection 40 is located at the air inlet 1
6 is located at the same position as the edge 16b on the nozzle block 30 side, and the tip end 40a is located at a position protruding in the direction of the pilot burner 20 from the edge 16a of the air inlet 16 on the pilot burner 20 side.

In the third embodiment, the air inlet 16
Is introduced from the beginning, the tapered surface 4
0b to the tip 40a, it is possible to synchronize well with the flow of the injection gas, and the tip 40a of the projection 40
The generation of eddy currents in the vicinity can be suppressed more reliably. As a result, the effect of preventing dust adhesion can be ensured.

[0020]

As described above, according to the first aspect of the present invention, since the projection is provided and the injection port is formed at the tip of the projection, a vortex of combustion air is generated near the injection port. Can be suppressed, and the injection port can be prevented from being blocked by dust. According to the second aspect of the present invention, since the position of the tip of the convex portion is made to protrude in the burner direction from the burner side edge of the air inlet, all of the combustion air introduced from the air inlet is this convex. Since it hits the outer peripheral surface of the portion, the generation of the vortex at the tip of the convex portion can be more reliably suppressed, and the clogging of the injection port with dust can be more reliably suppressed.
According to the third aspect of the present invention, since the outer periphery of the tip portion of the convex portion has a tapered surface, the combustion air can be tuned well with the injection gas,
Eventually, vortex generation can be suppressed, and dust adhesion can be prevented.
According to the fourth aspect of the present invention, the air introduced from the air introduction port flows from the beginning to the tip along the tapered surface of the convex portion, so that it can be well synchronized with the flow of the injection gas, and furthermore, the vortex flow Can be suppressed and dust adhesion can be prevented.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a gas injection nozzle according to a first embodiment of the present invention.

FIG. 2 is a side view showing a state in which a nozzle block and a pilot burner are connected via the gas injection nozzle.

FIG. 3 is an enlarged sectional view of a gas injection nozzle according to a second embodiment of the present invention.

FIG. 4 is an enlarged sectional view of a gas injection nozzle according to a third embodiment of the present invention.

FIG. 5 is an enlarged sectional view of a conventional gas injection nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Gas injection nozzle 11 Base part 12 Flat part 14 Gas passage 14a Injection port 15 Cylindrical part 16 Air inlet 16a Burner-side edge of air inlet 16b Gas supply member-side edge of air inlet 17 Convex part 17a Tip 17b Taper Surface 20 Pilot burner (burner) 21 Inlet of burner 30 Nozzle block (gas supply member) 31 Gas passage 40 Convex portion 40a Tip 40b Tapered surface

Claims (4)

[Claims] A base portion provided to close a base end side of the cylindrical portion and connected to a gas supply member; A gas passage is formed, a base end of the gas passage communicates with a gas passage of the gas supply member, and a tip of the gas passage faces the inside of the cylinder as an injection port, and an air introduction port is formed in the cylinder. In the injection nozzle, the base portion has a convex portion disposed in the cylindrical portion,
The gas passage passes through the projection, and the injection port is open at the tip of the projection. The tip of the projection is located at a position protruding in the burner direction from the edge of the air introduction port on the gas supply member side. A gas injection nozzle characterized by the above-mentioned. 2. The gas injection nozzle according to claim 1, wherein a tip of the convex portion is located at a position protruding in a burner direction from a burner side edge of the air inlet. 3. The base portion has a flat plate portion closing a base end side of the cylindrical portion, and the cylindrical convex portion protruding from the flat plate portion, and a distal end portion of the convex portion has a tapered tapered surface. The gas injection nozzle according to claim 1, wherein the gas injection nozzle is provided. 4. The gas injection nozzle according to claim 2, wherein the convex portion has a tapered surface, and the air introduction port is radially opposed to the tapered surface.