JPH0634110A - Combustion device - Google Patents

Abstract

PURPOSE:To switch a variable density combustion and a Bunsen combustion by a simple construction. CONSTITUTION:A gas nozzle 8 is provided in a main passage 5 to which a combustion air is supplied. The downstream side of the gas nozzle 8 is divided to a first passage 4 and a second passage 6. The distribution of fuel gas to both the passages is adjusted by adjusting the angle, position of the gas nozzle 8 or the like through an actuator 10. In case of a Bunsen combustion, the gas nozzle 8 is directed to the first passage 4 to supply the fuel gas to the first passage 4. In case of a variable density combustion, the gas nozzle 8 is directed to the second passage side to supply a part of the fuel gas to the second passage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustor of forced combustion type.

[0002]

2. Description of the Related Art Conventionally, in a gas combustion apparatus of variable capacity, a gas lean passage and a gas rich passage are provided.
When the capacity is high to medium, a part of the fuel gas is flowed not only in the gas rich passage but also in the gas lean passage to carry out rich and lean combustion. It has been known. For example, in Japanese Patent Laid-Open No. 3-247907, a fuel gas supply system path is branched into a first system path and a second system path, a proportional valve is provided in each system path, and a proportional valve provided in the second system path. Combustion that switches between a state in which only secondary air for combustion is ejected from the outlet that ejects secondary air for combustion (Bunsen combustion) and a state in which a lean mixed gas is ejected (concentration combustion) by controlling the opening and closing of the valve A device is disclosed.

[0003]

However, in such a conventional device, two gas supply system passages must be provided, and the construction becomes complicated due to the routing of gas conduits. Naturally, a gas nozzle and a proportional valve are required for each gas supply system path, and the number of parts also increases. A combustion apparatus of the present invention has an object to solve the above-mentioned problems and to switch between rich and lean combustion and Bunsen combustion with a simple configuration.

[0004]

In the combustion apparatus of the present invention for solving the above problems, a gas nozzle is provided in a main passage to which combustion air is supplied by a fan, and a main passage on the downstream side of the gas nozzle communicates with a flame hole. A first passage for gas rich,
There is provided an adjusting means for branching to a secondary passage for gas lean, which serves as a secondary air or lean mixed gas passage for the flame of the flame hole, and for adjusting a gas amount distribution from the gas nozzle to the first passage and the second passage. The point is to have prepared.

As the adjusting means, a direction changing means for changing the gas ejection direction of the gas nozzle, a position changing means for changing the position of the gas nozzle, or a diffusion angle changing means for changing the gas ejection diffusion angle of the gas nozzle may be used. Good. Further, the adjusting means may be composed of a resistor provided between the gas nozzle and the passage branching position, and a flow passage changing means for changing the shape, position or angle of the resistor to change the flow passage form.

[0006]

In the combustion apparatus of the present invention having the above-described structure, the combustion air is supplied to the main passage by the fan and is divided into the gas rich first passage and the gas lean second passage on the way. Then, the fuel gas is ejected from a gas nozzle provided slightly upstream of the branch position of the both passages and mixed with the combustion air. In this case, the distribution of the combustion gas amount flowing through each passage is set by the adjusting means. Therefore, the first
If the fuel gas is supplied only to the passage, only the combustion air flows in the second passage and is used as the secondary air of the flame in the flame hole to enable Bunsen combustion. On the contrary, if the distribution adjustment is performed so that a part of the fuel gas is caused to flow into the second passage, the lean mixed gas is sent from the second passage, and the rich / lean combustion becomes possible. Therefore, it is possible to switch between Bunsen combustion and rich / lean combustion with a simple configuration without providing a gas conduit, a proportional valve, or the like for each gas lean and gas rich as in the conventional case.

The distribution adjustment of the fuel gas can be performed by changing the jetting direction of the gas nozzle. For example, if the gas nozzle is directed to the first gas rich passage, the gas inflow to the second gas lean passage is suppressed. Conversely, if the gas nozzle is tilted toward the second passage, part of the fuel gas will also flow into the second passage at a rate according to the direction of the gas nozzle.

It is also possible to change the position of the gas nozzle. For example, if the gas nozzle is brought closer to the inlet of the first passage, the gas inflow into the second passage is suppressed, and conversely,
If the gas nozzle is away from the first passage inlet, or
By moving the fuel gas to the second passage side, a part of the fuel gas also flows into the second passage at a rate according to the position of the gas nozzle.

Further, the distribution of the fuel gas can be adjusted by changing the gas ejection diffusion angle of the gas nozzle. For example,
When the gas nozzle is adjusted toward the first passage and the gas ejection angle is adjusted to be small, the gas inflow into the second passage is suppressed, and if the gas ejection angle is increased from this state, a part of the fuel gas becomes the ejection diffusion angle. It also flows into the second passage at a proportion.

Further, by providing a resistor in front of the gas nozzle and adjusting its shape, position or angle, distribution of fuel gas can be adjusted. That is, by adjusting the flow direction of the fuel gas by the resistor, when the Bunsen combustion is performed, the flow of the fuel gas into the second passage is blocked, and conversely, when the rich-lean combustion is performed, A part of the fuel gas is made to flow into the second passage.

It should be noted that the switching between the Bunsen combustion and the rich / lean combustion is not limited to simply switching in two ways, and the fuel gas distribution may be adjusted in a plurality of steps or steplessly.

[0012]

EXAMPLES In order to further clarify the constitution and operation of the present invention described above, preferred examples of the combustion apparatus of the present invention will be described below.

FIG. 1 shows a schematic structure of a combustion apparatus as one embodiment, in which a plurality of burner units 2 are provided in a box body 1.
(Only one on the front side is shown in the drawing) are arranged side by side with a predetermined interval (see the right side view shown in FIG. 6). A plurality of flame holes 3 are formed in the upper portion of the burner unit 2, and a first passage 4 which is a throat for sending the mixed gas to the flame holes 3 extends laterally below. The upstream side of the first passage 4 communicates with a main passage 5 to which combustion air is supplied from an air supply fan (not shown). Further, the main passage 5 communicates not only with the first passage 4 but also with the box body 1 below the first passage 4. Hereinafter, the passage through which the combustion air in the box 1 flows will be referred to as the second passage 6. That is, the second passage 6 is formed in the lower portion of the box body 1 and in the gaps between the burner units 2. In this way, the combustion air supplied from the main passage 5 is divided into the first passage 4 and the second passage 6 (the flow is indicated by a dashed arrow). Reference numeral 7 in the drawing denotes a perforated straightening plate provided in the second passage 6.

A gas nozzle 8 is provided in the main passage 5 slightly upstream of the flow dividing position. The gas nozzle 8 is
While being rotatably supported by a shaft 9 extending in the front-rear direction,
It is connected to one flexible gas conduit (not shown).
The rotational position of the gas nozzle 8 is changed to the actuator 10
Controlled by. As this actuator 10,
Examples include motors and solenoids. For example, in FIG.
As shown in (C), a connecting bar 11 is extended rearward from the gas nozzle 8 and a free end portion of the connecting bar 11 is swung by a spindle 13 which is moved forward and backward by a solenoid 12 to move the gas nozzle 8 in a predetermined direction. Can be turned to.

In this embodiment, when the capacity (gas amount) is set to be small, the gas nozzle 8 is directed toward the first passage 4 and the fuel gas is supplied to the first passage 4 as shown in FIG. 1 (A). Flow (the flow of fuel gas is indicated by a solid arrow).
Therefore, the mixed gas of the fuel gas and the combustion air flows in the first passage 4, and only the combustion air flows in the second passage 6. In this way, the rich air-fuel mixture is ejected from the flame holes 3 of the burner unit 2 and the combustion air (secondary air) is supplied from around it to perform Bunsen combustion (see FIG. 6).

On the contrary, when the ability is set to be large,
As shown in FIG. 1B, the gas nozzle 8 is slightly rotated toward the second passage 6 by the actuator 10 so that a part of the fuel gas also flows into the second passage 6. Thus, the second
A lean mixture is supplied to the passage 6. Therefore, a rich air-fuel mixture is ejected from the flame holes 3 of the burner unit 2 to form a main flame, and a leaner air-fuel mixture flows upward between the burner units 2 to form flame holding. That is, the light and shade combustion is performed. As a result, the production of nitrogen oxides is reduced as an effect of the rich-lean combustion while maintaining the same overall combustion amount.

Generally, in the case of performing the rich-lean combustion, the combustion becomes unstable when the capacity is reduced. Therefore, when the capacity is small, stable combustion is performed by performing Bunsen combustion with a high turndown ratio. Incidentally, in the case of such a small capacity, since the combustion amount itself is originally small, the generation amount of nitrogen oxides is also small, so there is no problem.

Further, in this embodiment, the direction of the gas nozzle 8 is adjusted by the actuator 10 according to the capacity set by the combustion control device (not shown), but the direction is automatically adjusted by using the shape memory alloy. May be
For example, a shape memory alloy that changes its shape in response to the temperature change of the burner 2 is used, and when the capacity is small, the burner temperature is increased to direct the gas nozzle 8 to the first passage 4 side by the shape memory alloy. Using the fact that the burner temperature decreases as the capacity increases, the burner temperature is inclined toward the second passage side 6 according to the temperature. In such a case, an electric actuator is unnecessary.

Next, a second embodiment will be described. In this embodiment, the gas amount distribution to the first passage 4 and the second passage 6 is adjusted by changing the position of the gas nozzle 8. For example, as shown in FIG. 2, the gas nozzle 8 is moved forward and backward with respect to the main passage 5, and when the capacity is low, the actuator 10 moves the gas nozzle 8 to the downstream side to move the gas nozzle 8 to the first side.
The fuel gas is made to flow only to the passage 4 side, and when the capacity is large, the fuel gas is moved to the upstream side so that a part of the fuel gas is also made to flow to the second passage 6. As the actuator 10 for changing the position of the gas nozzle 8, as described in the previous embodiment,
Examples include motors, solenoids, and shape memory alloys. Alternatively, the gas nozzle 8 may be moved in the vertical direction.

Next, a third embodiment will be described. In this embodiment, the distribution of gas amount to the first passage 4 and the second passage 6 is adjusted by changing the gas ejection diffusion angle of the gas nozzle 8. For example, as shown in FIG. 3, the slide cylinder 21 is slidably inserted outside the gas ejection cylinder 20 which is the tip of the gas nozzle 8, and the slide cylinder 21 is advanced and retracted by the actuator 10 to diffuse the gas ejection. Change the angle. For example, when the capacity is low, the slide cylinder 21 is retracted as shown in FIG. 3A to reduce the gas ejection diffusion angle so that the fuel gas is sent to the first passage 4. When the capacity is large, the slide cylinder 21 is moved forward so that the tip taper portion 21A thereof is continuous with the tip taper portion 20A of the gas ejection cylinder 20, as shown in FIG. In this case, the fuel gas flows along the tip end tapered portions 20A and 21A of the gas ejection cylinder 20 and the slide cylinder 21 to increase the ejection diffusion angle, and a part thereof is also sent to the second passage 6.

Next, a fourth embodiment will be described. In this embodiment, instead of moving the gas nozzle 8 itself, a resistor is provided in front of the gas nozzle 8 and the flow passage form is changed by this resistor to adjust the distribution of the fuel gas. For example, as shown in FIG. 4, a cylindrical resistor 30 having a front opening hole 31 provided in the gas injection direction and a plurality of side surface opening holes 32 provided in a direction orthogonal to the front opening hole 31 is arranged in front of the gas nozzle 8. At the same time, the slide cylinder 33 is slidably inserted into the outer peripheral surface of the cylindrical resistor 30, and the slide cylinder 33 is moved back and forth by the actuator 10 to adjust the opening degree of the side opening 32. When the capacity is small, the side opening 32 is closed by the slide cylinder 33 as shown in FIG. 4 (A), so that the fuel gas can flow to the first passage 4 side. As shown in FIG. 3B, the slide cylinder 33 is retracted to increase the opening degree of the side surface opening hole 32, the flow passage form of the fuel gas is changed, and a part of the fuel gas also flows to the second passage 6 side. To

Further, as shown in FIG. 5 (A), the plate-shaped resistance plate 41 rotatably supported by the shaft 40 is controlled by the actuator 10 to control the rotation angle thereof, thereby changing the flow path form. Alternatively, as shown in FIG. 5B, the resistance plate 42 oriented in a predetermined direction may be moved in the vertical direction or the horizontal direction.

The embodiment of the present invention has been described above.
The present invention is not limited to these examples, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention. The burner shape is not limited to the unit type and can be applied to various burners.

[0024]

As described in detail above, according to the combustion apparatus of the present invention, the distribution of the fuel gas flowing from the gas nozzle to the first passage and the second passage is adjusted. It is not necessary to separately provide a control valve or the like, and it is possible to switch between rich and lean combustion and Bunsen combustion with a simple structure.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a combustion device as a first embodiment.

FIG. 2 is a schematic configuration diagram of a combustion device as a second embodiment.

FIG. 3 is a schematic configuration diagram of a combustion device as a third embodiment.

FIG. 4 is a schematic configuration diagram of a combustion device as a fourth embodiment.

FIG. 5 is a schematic configuration diagram of a combustion device as a modified example of the fourth embodiment.

FIG. 6 is a schematic configuration diagram of a right side surface of the combustion device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Box body, 2 ... Burner, 3 ... Flame hole, 4 ... 1st passage, 5 ... Main passage, 6 ... 2nd passage, 8 ... Gas nozzle, 10 ... Actuator, 30 ... Cylindrical resistor, 3
3 ... slide cylinders, 41, 42 ... resistance plates.

Claims (5)

[Claims] 1. A gas nozzle is provided in a main passage to which combustion air is supplied by a fan, a gas-rich first passage communicating with a flame hole in a main passage on a downstream side of the gas nozzle, and a secondary air for a flame of the flame hole. Alternatively, the combustor is characterized by branching to a gas lean second passage that serves as a lean mixed gas flow passage, and having adjustment means for adjusting the gas amount distribution from the gas nozzle to the first passage and the second passage. . 2. The combustion apparatus according to claim 1, wherein the adjusting unit is a direction changing unit that changes a gas ejection direction of the gas nozzle. 3. The combustion apparatus according to claim 1, wherein the adjusting unit is a position changing unit that changes a position of the gas nozzle. 4. The combustion apparatus according to claim 1, wherein the adjusting unit is a diffusion angle changing unit that changes a gas ejection diffusion angle of the gas nozzle. 5. The adjusting means comprises a resistor provided between the gas nozzle and the branch position, and a flow path changing means for changing the shape, position or angle of the resistor to change the flow path form. The combustion apparatus according to claim 1, which comprises: