JPH1038221A - Gas burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate safe ignition with a simple construction, and improve a follow-up property to a combustion request in a gas burner. SOLUTION: A spark rod 7 is provided on part of a burner part 11, and a pilot gas nozzle 15 is disposed in the vicinity of the spark rod 7. There are formed branched from a fuel supply flow passage 3 a main gas flow passage 16 for supplying a gas fuel to the burner part 11 and a pilot gas flow passage 17 for supplying a gas fuel to the pilot gas nozzle 15. The time when the gas fuel reaches the burner part 11 through the pilot gas flow passage 17 from a branch part 18 is set to be the time or less the gas fuel reaches the burner part 11 through the main gas flow passage 17 from the branch part 18. Further, a control valve 21 is connected with the fuel supply flow passage 3 for controlling supply of the gas fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas burner.

[0002]

2. Description of the Related Art In a gas burner using a gas fuel such as city gas or LPG, generally, a small-capacity pilot burner is ignited once instead of directly igniting the entire burner, and the flame of the pilot burner (hereinafter, referred to as a flame of the pilot burner). The pilot flame is being fired.)

[0003] The reason is as follows. That is, even if the supply of gas fuel to the gas burner is started, the air-fuel ratio that can be burned is not immediately reached, but a considerable amount of gas fuel is ejected from the gas burner until the air-fuel ratio that can be burned by spark ignition is reached. Would. If the gas burner is ignited at once in this state, the pressure at the front of the gas burner sharply increases, and this increase in pressure affects the gas fuel supply line upstream of the burner, and the gas fuel supply is momentarily interrupted. for that reason,
Flames fluctuate or extinguish. This tendency becomes more remarkable as the combustion amount of the gas burner increases and the supply pressure of the gas fuel decreases. Therefore, as described above, this problem is avoided by once igniting a pilot burner having a relatively small capacity and igniting the entire burner with pilot flame as a pilot flame.

However, in the gas burner having such a configuration, it is necessary to provide at least an independent fuel supply path for a pilot burner for ignition, which complicates the structure and reduces the supply amount of fuel and combustion air. Adjustments are also complicated. Further, in a gas burner equipped with such a pilot burner, generally, a pilot combustion stage for burning the pilot burner for a certain period of time is performed. The time until the whole is ignited is delayed, and the ability to follow the combustion request is reduced. Also,
Since a pilot burner is provided in this manner, an expensive shut-off valve must be connected to the fuel supply path, which is more expensive than a liquid combustion burner.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to enable safe ignition of a gas burner with a simple structure and to improve the ability to follow a combustion request.

[0006]

According to the present invention, a spark rod is provided in a part of a burner portion, a pilot gas nozzle is arranged near the spark rod, and a main gas flow path for supplying gas fuel to the burner portion is provided. A pilot gas flow path for supplying gas fuel to the pilot gas nozzle is formed by branching from the fuel supply flow path, and the time required for the gas fuel to reach the burner from the branch section via the pilot gas flow path is determined by the branch time. The above-mentioned problem is solved by a configuration in which the time required for the gas fuel to reach the burner section from the section via the main gas flow path is set to be equal to or less than the required time.

Further, according to the present invention, the fuel supply flow path includes:
The above-mentioned problem is solved by a configuration in which a control valve for controlling the supply of gas fuel is connected.

Further, according to the present invention, a spark rod is provided in a part of a burner portion, a pilot gas nozzle is arranged near the spark rod, and a gas fuel is provided in a main gas passage for supplying gas fuel to the burner portion and a pilot gas nozzle. And a pilot gas flow path for supplying a first control valve and a second control valve respectively connected to the main gas flow path and the pilot gas flow path. The time required for gas fuel to reach the burner section from the control valve via the pilot gas flow path is set to be equal to or less than the time required for gas fuel to reach the burner section via the main gas flow path from the first control valve, The above problem is solved by a configuration in which the first control valve and the second control valve are opened substantially simultaneously.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is embodied in a gas burner. The gas burner according to the present invention has a spark rod provided in a part of a burner portion, and a pilot gas nozzle is arranged near the spark rod. Gas fuel is supplied to each of the burner section and the pilot gas nozzle via a main gas flow path and a pilot gas flow path branched from a fuel supply flow path. Further, the time required for the gas fuel to reach the burner from the branch via the pilot gas flow path is set to be equal to or less than the time required for the gas fuel to reach the burner via the main gas flow from the branch. Thus, the arrival time of the gas fuel to each burner is adjusted. The adjustment of the arrival time is performed for the main gas flow path and the pilot gas flow path.
This is performed by appropriately adjusting the diameter, length, and pressure loss of the pipe. In particular, for the adjustment of pressure loss, a throttle mechanism such as an orifice is used.

Here, the burner section is a place where actual combustion involving a flame is performed, and in a premix type burner, a nozzle for injecting gaseous fuel is used. Further, in the premix type burner, a nozzle for ejecting premixed gas, a flame holding plate having a large number of premixed gas ejection holes, and the like can be used. Further, the branch portion is a portion that branches from a fuel supply flow path to a main gas flow path and a pilot gas flow path.
The combustion air includes a case where the combustion air is supplied to the burner section and the pilot gas nozzle collectively, and a case where the combustion air is individually connected to each of the flow paths. Furthermore, the time required for the gas fuel to reach is defined as the time from the branch section to the burner section. However, this depends on the shape of the burner, such as the length of the nozzle or the like of the burner section and the mounting position. As a burner section where combustion takes place. For example, in a premixed gas burner, the tip of each of the nozzles may be provided at substantially the same position or a pilot gas nozzle may be provided on the downstream side. May be disposed, and the main gas nozzle may be disposed upstream of the pilot gas nozzle.

According to the above configuration, the gas fuel first reaches the pilot gas nozzle and forms a pilot flame. On the other hand, the gas fuel arrives at the burner part later than the pilot gas nozzle, so that the pilot flame ignites the burner part. Therefore, the ignition of the burner portion is not performed all at once for the gas fuel (mixed air) ejected from the entire burner portion, and the ignition can be performed without generating a loud ignition sound. Furthermore, there is no need to provide an emergency shut-off valve and an on-off valve independently for each of the flow passages, so that the structure can be simplified, and the pilot combustion stage becomes unnecessary due to a simple configuration in control. Therefore, the load followability is improved. For this reason, the load followability of a device (for example, a boiler) used with a gas burner attached thereto is improved, and an increase or decrease in load, particularly an increase in load, can be dealt with immediately.

In the present invention, the supply of gas fuel to the burner section and the pilot gas nozzle is controlled by connecting a control valve upstream of the branch section, that is, to a fuel supply flow path. This control valve includes not only one having two operating states, an open state and a closed state, but also one that continuously or stepwise controls the opening degree of the valve in the open state.

Further, as another embodiment of the present invention, similarly to the above-described embodiment, a spark rod is provided in a part of a burner portion, and a pilot gas nozzle is arranged near the spark rod, and a burner portion is provided. A main gas flow path for supplying gas fuel to the pilot gas flow path and a pilot gas flow path for supplying gas fuel to the pilot gas nozzle are formed by branching from the fuel supply flow path, and the main gas flow path and the pilot gas flow path are respectively formed. One control valve, and, while connecting the second control valve, the time required for the gas fuel to reach the burner section from the second control valve through the pilot gas flow path, from the first control valve through the main gas flow path The time is set to be less than the time required for gas fuel to reach the burner. Then, control is performed so that the first control valve and the second control valve are opened substantially simultaneously. That is, instead of connecting one control valve to the fuel supply flow path on the upstream side of the branch portion as in the above-described embodiment,
First and second control valves, which are simultaneously opened, are connected to the main gas flow path and the pilot gas flow path on the downstream side of the branch portion. According to this configuration, similarly to the above-described embodiment, the gas fuel first reaches the pilot gas nozzle to form a pilot flame, and the pilot flame allows the gas fuel to reach the burner later than the pilot gas nozzle. To ignite.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific embodiment of a gas burner according to the present invention will be described with reference to the drawings. FIG.
1 is a drawing for explaining a specific embodiment of a gas burner according to claims 1 and 2 of the present invention. The first embodiment shown in FIG. 1 shows an example in which the present invention is applied to a premix type gas burner. In the drawing, a gas burner is provided with a wind box 1 supplied with combustion air,
It comprises a burner element 2 attached to the downstream side of the wind box 1 and a fuel supply channel 3 for supplying gas fuel to the burner element 2.

In the first embodiment shown in the drawings, the wind box 1 is a cylindrical body having a substantially square cross section, and receives supply of combustion air from its upstream side (upper side in FIG. 1). Further, the wind box 1 is formed in a so-called tapered shape in which the cross-sectional area of the flow passage decreases toward the downstream side in the lower half. In this way, by forming the wind box 1 in a tapered shape, the premixed gas can be uniformly ejected from the burner element 2.

The burner element 2 is a member functioning as a burner section 11 for performing actual combustion. The burner element 2 itself has, for example, a large number of premixed gas injection holes formed in a heat-resistant flat plate member. A premixed gas ejection hole formed by alternately stacking corrugated plates and flat plates made of metal is used. Below, burner element 2
Will be described as the burner section 11.

A main gas nozzle 13 is provided in the wind box 1 upstream of the burner element 2 so as to cross the inside of the wind box 1.
The gas fuel ejected from the main gas nozzle 13 is mixed with combustion air supplied from the upstream side of the wind box 1 and then ejected to the surface side of the burner element 2 as an air-fuel mixture. Further, a pilot gas nozzle 15 is provided on the back surface on the upstream side of the burner element 2. The pilot gas nozzle 15 is provided so that the tip thereof is opposed to the back surface of the burner element 2 in a state of being close to the back surface. The gas fuel ejected from the pilot gas nozzle 15 mixes with the combustion air supplied from the upstream side of the wind box 1 on the back side of the burner element 2, and then ejects the mixture as a mixture on the front side of the burner element 2.

Therefore, as described above, the burner element 2
Functions as a combustion section 11 that receives a supply of gaseous fuel from a main gas nozzle 13 and performs actual combustion.
Is arranged, a pilot flame can be formed in this portion. Hereinafter, a portion where the pilot flame is formed in the combustion portion 11 is referred to as a pilot flame portion 12. Here, when forming the pilot flame portion 12 in the burner portion 11, on the back surface side of the burner element 2, a part may be partially defined to form only the pilot flame. Here, the main gas nozzle 13 is provided with a plurality of gas ejection holes 14 on a side surface thereof. With this configuration, gas fuel is introduced as uniformly as possible into a combustion air flow in the wind box 1 so that the It improves the mixing of air and gaseous fuel. on the other hand,
In the pilot flame section 12, the burner element 2
The pilot gas nozzle 15 is arranged in close proximity to the back surface of the burner element 2 and is also configured to eject fuel gas in a narrow range. A mixture with an air-fuel ratio of

The main gas nozzle 13 and the pilot gas nozzle 15 are respectively provided with a main gas passage 16 and a pilot gas passage 1 for supplying fuel gas.
7 is connected. The main gas flow path 16 and the pilot gas flow path 17 branch off from the fuel supply flow path 3 and receive gas fuel from the fuel supply flow path 3 respectively. In the fuel supply passage 3, two shutoff valves 19 and 20 are connected on the way, and a control valve 21 is connected between them. Each of the flow paths 16 and 17 is provided with a branch portion 18 at a position downstream of the shutoff valve 19 on the downstream side in the fuel supply flow path 3.
Branches from.

Here, the main gas passage 16 and the pilot gas passage 17 are set as follows. The control valve 2
After opening 1, the time required for the gas fuel to reach the pilot flame section 12 from the branch section 18 via the pilot gas flow path 17 and the pilot gas nozzle 15 is changed from the branch section 18 to the main gas flow path 16 and the main gas nozzle 13. The length, diameter, and pressure loss of the main gas flow path 16 and the pilot gas flow path 17 are selected so as to be shorter than the time required to reach the burner section 11 via the main gas path. More specifically, the pilot gas passage 17 is made shorter than the main gas passage 16 or the second orifice 2
For example, the pressure loss due to 3 is made smaller than the pressure loss due to the first orifice 22 in the middle of the main gas passage 16 so as to increase the flow velocity and shorten the arrival time. Further, in the first embodiment,
Since the main gas nozzle 13 is located upstream of the pilot gas nozzle 15 in the burner duct 1, the arrival time is set in consideration of a time difference according to this distance.

Further, a spark rod 7 is provided near the pilot gas nozzle 15 in the combustion section 11. The tip of the spark rod 7 is located on the surface side of the burner element 2 and is opposed to the pilot gas nozzle 15 with the burner element 2 interposed therebetween. Accordingly, the operation of the spark rod 7 ignites the fuel gas (premixed gas) ejected from the pilot gas nozzle 15 through the burner element 2, and a pilot flame is generated in the pilot flame portion 12.

The opening and closing of the control valve 21 in the fuel gas passage 3 and the operation of the spark rod 7 are controlled by a control device 30.
Done by The control device 30 also controls the entire burner.

According to the above configuration, when the control valve 21 is opened while the spark rod 7 is energized, the fuel supply flow path 3
From the main gas flow into the main gas flow path 16 and the pilot gas flow path 17. Then, the gas reaches the burner section 11 through the respective flow paths 16 and 17. Since the arrival time at the pilot flame section 12 is shortened as described above, the gas from the pilot gas flow path 17 is used. The fuel first reaches the burner element 2. In the pilot flame section 12, the pilot gas flow path 1
The gas fuel from 7 is mixed with the combustion air ejected from the burner element 2. At this time, pilot flame 1
2 is an area narrower than the entire burner section 11, and furthermore, an air-fuel mixture is formed at a position close to the spark rod 7, so that the mixing ratio is such that combustion is possible instantaneously, and a pilot flame is formed.

Slightly after the gas fuel reaches the pilot flame section 12, the main gas flow path 1
Gas fuel from 6 arrives. Here, the gas fuel supplied via the main gas passage 16 is supplied relatively upstream of the wind box 1 (at least upstream of the burner element 2 in the first embodiment), and is used for combustion. The air mixes as it flows toward the burner element 2 to become a premixed air. Therefore, in the burner element 2, the mixture is not supplied instantaneously with a predetermined concentration, but gradually increases in concentration. And
When this concentration becomes a combustible concentration, it is ignited by the pilot flame and starts main combustion. That is,
With the above configuration, the ignitable gas concentration is quickly reached only near the ignition source, and a part of the burner element 2
That is, a pilot flame is quickly formed in the pilot flame portion 12.

After a pilot flame (pilot flame) is formed in the pilot flame section 12 as described above, the burner section 11
Since the premixed gas is blown out from the burner section 11, the pilot flame section 12 ignites the burner section 11 by the pilot flame. This ignition is substantially direct ignition. However, since the pilot flame of the pilot flame portion 12 is slightly ignited earlier, sufficient heat is applied to the ignition of the burner portion 11 and the burner is smoothly performed without delay of ignition. The ignition of the part 11 is performed. Here, the ignition of the burner section 11 is performed smoothly, but it is preferable that the combustion amount of the pilot flame be ignited at about 30% of the whole in order to suppress a rapid rise in pressure at the front of the burner section 11. Therefore, with this configuration, the gas concentration near the ignition source (in this case, the spark rod) is increased, and the entire burner can be ignited smoothly by turning on the pilot light first.

In the first embodiment described above, the case where the present invention is applied to a premixed gas burner has been described. However, the present invention can be applied to burners of a type other than the above-described premixed gas burner. . FIG. 2 shows an example in which a premix gas burner is applied as another type of burner.
This will be described below based on

The wind box 1 of the second embodiment has a cylindrical shape, and a main gas nozzle 13 is attached so as to penetrate the wind box 1 in the vertical direction in FIG. Combustion air is introduced into the wind box 1 from the side thereof, and is introduced into the air register 5 in a state where the drift is reduced by the straightening plate 4 coaxially arranged in the wind box 1. The flame holding plate 6 is attached to the tip of the main gas nozzle 13. The pilot gas nozzle 15 is disposed inside the main gas nozzle 13 so that its axis is substantially the same direction. The spark rod 7 serving as an ignition means is disposed so as to face the tip of the pilot gas nozzle 15.

In the structure of the second embodiment, the main gas flow path 16 and the pilot gas flow path 17 are opened by the control valve 21 and the gas fuel flows from the branch section 18 to the pilot gas passage, as in the first embodiment. The time required to reach the pilot flame section 12 via the gas flow path 17 and the pilot gas nozzle 15 is shorter than the time required to reach the burner section 11 from the branch section 18 via the main gas flow path 16 and the main gas nozzle 13. Next, the length, diameter, and pressure loss of the main gas passage 16 and the pilot gas passage 17 are selected. Here, in the configuration of the second embodiment, since the tip portion of the main gas nozzle 13 and the tip portion of the pilot gas nozzle 15 are substantially at the same position, the gas fuel is supplied from the branch portion 18 to the tip portions of the nozzles 13 and 15. Is approximately the same as the time required for the gas fuel to reach the burner section 11 and the pilot flame section 12 from the branching section 18, respectively. Therefore, the gas fuel reaches the tips of the nozzles 13 and 15. The main gas flow path 16
And the setting of the pilot gas flow path 17 may be performed. In the second embodiment, the function and effect of setting the arrival time of the gaseous fuel by pipes are the same as in the first embodiment, and will not be described.

Further, in the above first and second embodiments, each of the flow passages 16 and 17 is configured to communicate with the fuel supply flow passage 3 by one control valve 21 so that gas fuel is supplied. However, as in the third embodiment shown in FIG. 3, each of the pipes to the gas nozzles 13 and 15 has two shutoff valves 2.
4, 25, 26, 27, and between the two shut-off valves 24, 25, 26, 27 in each flow path 16, 17, the first,
The second control valves 28 and 29 are connected, and the first and second control valves 2 are connected.
It is good also as a structure which opens 8 and 29 simultaneously. In the third embodiment, the time required for the gas fuel to reach the burner section 11 (or the pilot flame section 12) from the second control valve 29 via the pilot gas flow path 17 is determined by the first control valve 28. The time is set to be equal to or less than the time required for the gas fuel to reach the burner section 11 via the main gas flow path 16. The specific setting procedure is the same as the first and second embodiments,
Set by adjusting the pipe diameter, orifice diameter, pressure loss, etc.

The structure of the third embodiment is different from that of the first and second embodiments in that one control valve 21 is connected to the fuel supply flow path 3 upstream of the branch 18 instead of the branch. 18
Downstream main gas flow path 16 and pilot gas flow path 1
7, the first and second control valves 28, 2 which open simultaneously
9 are connected. In this configuration, as in the first and second embodiments, the gas fuel is first supplied to the pilot flame portion 12.
To form a pilot flame, and the pilot flame can safely ignite the gas fuel that reaches the burner section 11 behind the pilot gas nozzle 15.

[0031]

As described above, according to the first to third aspects of the present invention, the fuel gas ejected from the pilot gas nozzle is ignited by the spark rod to form a pilot flame. Since the pilot flame ignites the premixed gas ejected from the burner with a slight delay, a pilot combustion stage is not required.
Therefore, the load followability is improved. Further, the ignition of the burner is not performed at once for the entire burner, but the pilot flame starts burning first, and the flame of the pilot flame ignites the burner. Can be ignited without occurring. Therefore, in a boiler to be used with a gas burner attached, the load followability is improved, and it is possible to immediately respond to an increase / decrease in load, especially an increase in load.

Further, according to the first and second aspects of the present invention, the emergency supply system for the main burner and the fuel supply system for the pilot burner are independently provided as in the prior art. There is no need to provide a shut-off valve and an on-off valve, and an emergency shut-off valve and an on-off valve may be provided only in the fuel supply flow path, so that the structure can be simplified.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a second embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a configuration of a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 3 fuel supply passage 7 spark rod 11 burner section 12 pilot flame section 15 pilot gas nozzle 16 main gas passage 17 pilot gas passage 18 branch section 21 control valve 28 first control valve 29 second control valve

Claims (3)

[Claims] A spark rod (7) is provided on a part of a burner (11).
The pilot gas nozzle 15 is disposed near the spark rod 7, and a main gas flow path 16 that supplies gas fuel to the burner unit 11 and a pilot gas flow path 17 that supplies gas fuel to the pilot gas nozzle 15 are provided with fuel. The time required for the gas fuel to reach the burner section 11 from the branch section 18 through the pilot gas flow path 17 through the branch section 18 through the main gas flow path 16 A gas burner characterized in that the time is set to be equal to or less than the time required for gas fuel to reach the burner section 11. 2. A gas burner according to claim 1, wherein a control valve for controlling the supply of gaseous fuel is connected to said fuel supply passage. 3. A spark rod 7 is provided on a part of the burner portion 11.
The pilot gas nozzle 15 is disposed near the spark rod 7, and a main gas flow path 16 that supplies gas fuel to the burner unit 11 and a pilot gas flow path 17 that supplies gas fuel to the pilot gas nozzle 15 are provided with fuel. The main gas passage 16 is formed by branching off from the supply passage 3.
And the first control valve 2 in each of the pilot gas passages 17.
8 and the second control valve 29, and the burner unit 1 is connected to the second control valve 29 via the pilot gas flow path 17.
1 is set to be equal to or less than the time required for the gas fuel to reach the burner section 11 from the first control valve 28 via the main gas flow path 16, and the first control valve 28
And the second control valve 29 is opened substantially simultaneously.