JP2001221425A - Combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safe combustor by preventing oscillating combustion. SOLUTION: A combustor comprises a fuel supply device 11 for supplying fuel, a combustion air supply device 12 for supplying combustion air, a burner 13 for mixing and combusting the fuel and the combustion air, a heat chamber 14 which communicates with the burner 13 and directs combustion gas to a downstream side while keeping combustion, a heat exchanger 15 which communicates with the heat chamber 14 and directs the combustion gas to the downstream side while exchanging heat with the combustion gas, and an exhaust unit for discharging the combustion gas outside of the combustor. The exhaust unit comprises a main exhaust passage 16 communicating with the heat exchanger 15 and a short-circuit passage 17 which loads the gas directly to the passage 16 without passing through the heat exchanger 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustor used for a heater or the like.

[0002]

2. Description of the Related Art Conventionally, this type of combustor mixes fuel and air supplied by a fuel supply device 1 and a combustion air supply device 2 and burns them in a burner section 3, as shown in FIG.
Then, the high-temperature combustion gas generated by the combustion is completely combusted by the combustion tube 4 communicating with the burner section 3 as shown by an arrow, and is guided to a heat exchanger 5 provided downstream thereof. After the heat is exchanged in the heat exchanger 5, the heat is guided to the exhaust unit 6 and discharged out of the apparatus.

[0003]

However, in the above-mentioned conventional configuration, when the burner is downsized to perform high load combustion in order to make the combustor compact and low NOx as in recent years, the combustion gas Since the jetting speed of the fuel becomes high, the combustion frequency is easily matched with the natural frequency of the supply / exhaust passage of the device.

[0004] Furthermore, as the size of the heat exchanger is reduced due to the downsizing of the equipment, the exhaust path is lengthened in order to ensure thermal efficiency, which causes a problem that vibration combustion is more likely to occur. .

[0005] In addition, the oscillation combustion occurs when the flame resonates with the acoustic natural frequency of the supply / exhaust path of the equipment. Therefore, once it occurs, it cannot be prevented unless a significant change such as a review of the supply / exhaust path is made. It was difficult.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a combustor that does not easily generate oscillating combustion even in a burner that performs high-load combustion.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention provides a fuel supply device for supplying fuel, a combustion air supply device for supplying combustion air, and a fuel and combustion air supply device. A burner that mixes and burns, a combustion tube that communicates with the burner and guides combustion gas to the downstream while continuing combustion, and a heat exchanger that communicates with the combustion tube and exchanges heat with the combustion gas to downstream. An exhaust unit for discharging the combustion gas out of the machine, the exhaust unit comprising a main exhaust path connected to a heat exchanger and a short-circuit path that directly leads to the main exhaust path without passing through the heat exchanger. .

According to the above invention, the structure of the exhaust part for discharging the combustion gas to the outside of the machine is constituted by the main exhaust path passing through the heat exchanger and the short-circuit path provided so as to bypass the heat exchanger. The natural frequency of the exhaust path formed by any type of heat exchanger can be easily changed, and the occurrence of oscillating combustion can be prevented. In other words, in order to prevent oscillating combustion, the exhaust path,
It is not necessary to limit the form of the heat exchanger, and it is possible to design a heat exchanger that takes into account only the compactness of equipment and thermal efficiency, and to provide a highly safe combustor that is not affected by use conditions. Can be.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 comprises a fuel supply device for supplying fuel, a combustion air supply device for supplying combustion air, and a burner for mixing fuel and combustion air for combustion. A combustion cylinder that communicates with the burner and guides combustion gas downstream while continuing combustion; a heat exchanger that communicates with the combustion cylinder and guides combustion gas downstream while exchanging heat; and The exhaust unit includes a main exhaust path communicating with the heat exchanger and a short-circuit path that leads directly to the main exhaust path without passing through the heat exchanger.

[0010] Since the structure of the exhaust part for discharging the combustion gas to the outside of the machine is constituted by a main exhaust path passing through the heat exchanger and a short-circuit path provided so as to bypass the heat exchanger,
The natural frequency of the exhaust path formed by any type of heat exchanger can be easily changed, and the occurrence of oscillating combustion can be prevented. In other words, there is no need to restrict the exhaust path, that is, the form of the heat exchanger, in order to prevent oscillating combustion. It is possible to provide a highly safe combustor which is not affected by the heat.

The invention according to claim 2 is a fuel supply device for supplying fuel, a combustion air supply device for supplying combustion air, a burner for mixing fuel and combustion air for combustion, A combustion tube that communicates with the burner and guides combustion gas to the downstream side while continuing combustion; a heat exchanger that communicates with the combustion tube and exchanges heat with the combustion gas to downstream side; and discharges the combustion gas out of the machine. The heat exchanger includes a main path having a long flow path to the exhaust section and a short-circuit path having a short flow path to the exhaust section with respect to the main path.

According to a third aspect of the present invention, the heat exchanger is formed of a plurality of stages of plate-type heat exchangers, and the combustion gas is led to the exhaust unit via the plate-type heat exchangers of all stages. A path and a short-circuit path that does not pass through at least one or more plate-type heat exchangers among a plurality of stages are provided.

Since the heat exchanger is provided with two paths, a main path having a long flow path to the exhaust portion and a short-circuit path having a short flow path, the path resistance of the main path and the short-circuit path is stabilized. It is necessary to adopt a complicated configuration in which the natural frequency can be easily changed by the heat exchanger itself, which constitutes the main part of the exhaust path, and a short-circuit path is formed by another component. No, very simple configuration,
In addition, the occurrence of vibration combustion can be prevented in a small space.

According to a fourth aspect of the present invention, in the heat exchanger including the two-stage plate type heat exchanger, the plate type heat exchanger on the upstream side near the burner is divided into two chambers. The room has an inlet through which the combustion gas flows from the burner section, and a connection for guiding the combustion gas to the second plate heat exchanger as a main path, and the other room has a second plate heat exchanger. An inlet portion into which the combustion gas from the exchanger flows,
It has a connecting portion for guiding the combustion gas to the exhaust portion, and a short-circuit path through which the combustion gas can flow is provided between the two chambers. In a plate heat exchanger limited to a two-stage plate heat exchanger, the connection between the short-circuit path and the exhaust unit is integrally performed in the heat exchanger, so that the connection between the heat exchanger and the exhaust unit is one. It is possible to simplify the configuration and to prevent the occurrence of oscillating combustion.

The invention according to claim 5 is configured such that a means for increasing the passage resistance is provided in the short-circuit path so that the flow rate of the combustion gas passing through the short-circuit path is smaller than the flow rate of the combustion gas passing through the main path. I have.

Further, in the invention according to claim 6, a portion having a reduced flow path area is provided in a part of the short-circuit path so as to increase the passage resistance.

Since the short-circuit path has a short length and a small passage resistance, when a large amount of combustion gas flows, the exhaust gas temperature rises and the thermal efficiency decreases. Therefore, means for increasing the passage resistance, for example, by providing a portion having a reduced passage area in a part of the short-circuit path to increase the passage resistance,
Oscillation combustion can be prevented while suppressing a decrease in the thermal efficiency of the heat exchanger.

In the invention according to claim 7, the passage resistance is adjusted by changing the length of a portion having a small flow path area provided in a part of the short circuit path. Then, even when the acoustic natural frequency of the device changes depending on the installation conditions of the extension pipe or the like, the vibration combustion can be prevented by changing the length of the short-circuit path.

In the invention according to claim 8, means for varying the flow path area is provided in a part of the short-circuit path to adjust the path resistance.

By adjusting the passage resistance of the short-circuit path, the ignition resistance can be reduced by reducing the passage resistance at the time of ignition or the like where vibration combustion easily occurs, and the passage resistance can be increased by increasing the passage resistance during combustion. The vibration combustion can be prevented while minimizing the decrease in the thermal efficiency.

[0021]

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

FIG. 1 is a sectional view of a combustor according to a first embodiment of the present invention. 11 is an electromagnetic pump (fuel supply device), 12 is a blower fan (combustion air supply device), 13
Is a burner section for mixing and burning fuel and air, 14 is a combustion cylinder provided in communication with the burner section 13, and 15 is a heat exchanger for exchanging heat of combustion gas guided from the combustion cylinder. It is composed of plate heat exchangers 15a and 15b. 1
Reference numeral 6 denotes a main exhaust path that constitutes an exhaust section, and discharges the combustion gas that has passed through the heat exchanger 15 to the outside of the machine. Reference numeral 17 denotes a short-circuit path that constitutes an exhaust part, and is configured to directly lead the combustion gas to the main exhaust path 16 without passing through the heat exchanger 15.

The operation of the above configuration will be described. The fuel supplied from the electromagnetic pump 11 and the air supplied from the blower fan 12 are mixed with the air, and an appropriate ignition means (not shown) is applied to the burner 13.
To ignite and burn. At this time, the burner 13
Is designed to be considerably compact for the purpose of downsizing the equipment. In order to secure a predetermined amount of combustion, the injection speed of the mixed gas is high and high load combustion is performed. For this reason, the flow velocity of the combustion gas generated by the combustion becomes considerably high, and as shown by the arrow, first, the combustion cylinder 14
Heat exchanger 1 that is completely burned through
It is led to 5. Further, in the present embodiment, a configuration in which the radiator 14a is disposed in the combustion cylinder 14 is shown.
The combustion gas inside heats the radiator 14a to radiantly heat the front surface of the main body.

Next, the combustion gas having a high flow rate introduced into the heat exchanger 15 is discharged outside the machine via the heat exchanger 15 from the main exhaust path 16 connected to the final end.

Conventionally, when a high-velocity combustion gas passes through this path, resonance occurs in accordance with the natural frequency of the path, and a phenomenon occurs in which oscillating combustion occurs.

Therefore, in the present invention, a part of the combustion gas guided from the combustion cylinder 14 to the heat exchanger 15 is bypassed to the main exhaust path 16 by bypassing the heat exchanger 15 via the short-circuit path 17. . As a result, the natural frequency of the path through which the combustion gas passes can be changed, and even if the combustion gas with a high flow velocity passes, combustion can be continued normally without causing oscillating combustion.

In other words, the shape of the heat exchanger 15 needs to be longer than a certain level due to the restriction of securing thermal efficiency, and the shape of the heat exchanger 15 is changed in order to change the natural frequency of the combustion gas path. There are limits to changing. Therefore,
In the regulated heat exchanger 15, as described above, the short-circuit path 17 is provided as a means for changing the natural frequency, and the vibration generated by resonating with the acoustic natural frequency of the device is set by setting the optimum condition. I try to prevent combustion.

(Embodiment 2) FIG. 2 is a sectional view of a combustor according to Embodiment 2 of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the second embodiment, the short-circuit path 17 is formed by connecting the inlet side and the vicinity of the outlet side of the heat exchanger 15 and the heat exchanger 15
A main path having a long flow path to the main exhaust path 16 and a short-circuit path 17 having a short flow path are formed therein.

In the above-described configuration, since the configuration of the heat exchanger 15 is used, no extra piping or space is required for the short-circuit path 17, and the vibration combustion can be handled with a simple configuration.

Also, by reducing the passage area of the short-circuit path 17 and increasing the heat radiation area, the heat exchanger 1
5, while suppressing a decrease in thermal efficiency, it is possible to cope with vibration combustion.

(Embodiment 3) FIG. 3 is a sectional view of a combustor according to Embodiment 3 of the present invention. The same parts as those in the first and second embodiments are denoted by the same reference numerals, and the description is omitted.

Embodiment 3 is a two-stage plate heat exchanger 1
A heat exchanger 15 composed of 5a and 15b is provided, and the upstream heat exchanger 15a is divided into two rooms 18a and 18b. The room 18a has an inlet 19 into which the combustion gas from the combustion tube 14 flows, and a connecting portion 20 for guiding the combustion gas to the second-stage downstream heat exchanger 15b as a main path. Inlet 21 into which the combustion gas from vessel 15b flows
And a connecting portion 22 for guiding the combustion gas to the main exhaust path 16,
A short-circuit path 17 through which the combustion gas flows is provided between the chambers 18a and 18b.

In the above configuration, in the heat exchanger 15 including the two-stage plate heat exchangers 15a and 15b, the second-stage downstream heat exchanger 15b from the upstream heat exchanger 15a close to the burner as an exhaust path is used. As described above, in addition to the main path exhausted outside from the main exhaust path 16 again through the room 18b of the upstream heat exchanger 15a, the upstream heat exchanger 15a
A short circuit path 17 is provided by communicating the two rooms 18a and 18b provided in the heat exchanger, and the short circuit path 17 and the exhaust unit 16 are connected integrally in the heat exchanger.
And the exhaust unit 16 can be connected at one place, the configuration can be simplified, and by setting the short-circuit path 17 to the optimum condition, it is possible to prevent the occurrence of oscillating combustion while suppressing a decrease in thermal efficiency. it can.

(Embodiment 4) FIG. 4 is a sectional view of a combustor according to Embodiment 4 of the present invention. The same parts as those in the first, second, and third embodiments are denoted by the same reference numerals, and description thereof is omitted.

In the fourth embodiment, means for increasing the passage resistance of the short-circuit path 17, for example, by disposing a resistor 23 or changing the length of the short-circuit path 17, reduces the flow rate of the combustion gas passing through the short-circuit path 17. The configuration is such that the flow rate of the combustion gas passing through the main path is smaller than the flow rate.

In the above configuration, even if the acoustic natural frequency of the device changes depending on the installation conditions such as the extension piping,
By changing the length L of the short-circuit path 17 or disposing the resistor 23, the natural frequency of the exhaust path can be changed so as not to resonate with the changed natural frequency, thereby preventing vibration combustion. .

(Embodiment 5) FIG. 5 is a sectional view of a combustor according to Embodiment 5 of the present invention. The same parts as those in the first, second, and third embodiments are denoted by the same reference numerals, and description thereof is omitted.

In the fifth embodiment, the path resistance of the short-circuit path 17 can be adjusted by the damper 24.

In the above configuration, by adjusting the damper 24, the passage resistance of the short-circuit path 17 is changed. At the time of ignition where vibration combustion is likely to occur, the passage resistance is reduced to suppress vibration combustion. Vibration combustion is prevented while increasing the passage resistance to minimize the decrease in the thermal efficiency of the heat exchanger.

[0041]

As described above, according to the first aspect of the present invention, the structure of the exhaust unit for discharging the combustion gas to the outside of the machine is such that the main exhaust path passing through the heat exchanger and the heat exchanger are bypassed. , The natural frequency can be easily changed in the exhaust path constituted by any form of heat exchanger, and the occurrence of oscillating combustion can be prevented. . In other words, there is no need to restrict the exhaust path, that is, the form of the heat exchanger, in order to prevent oscillating combustion. It is possible to provide a highly safe combustor which is not affected by the heat.

According to the second and third aspects of the present invention,
Since the heat exchanger has two paths, a main path with a long flow path to the exhaust unit and a short-circuit path with a short flow path, a stable balance of the path resistance between the main path and the short-circuit path is ensured. In addition, the natural frequency can be easily changed by the heat exchanger itself, which constitutes the main part of the exhaust path, and there is no need to adopt a complicated configuration in which a short-circuit path is formed by separate parts, making it extremely simple. Occurrence of vibration combustion can be prevented with a configuration and space saving.

According to the fourth aspect of the present invention, the plate heat exchanger is limited to a two-stage plate heat exchanger, and the short circuit path and the exhaust portion are integrally connected in the heat exchanger. Therefore, the connection between the heat exchanger and the exhaust portion can be made at one place, so that the configuration can be simplified and the occurrence of oscillating combustion can be prevented.

According to the fifth and sixth aspects of the present invention,
Since the short-circuit path has a short length and a low passage resistance, when a large amount of combustion gas flows, the exhaust gas temperature rises and causes a decrease in thermal efficiency. Therefore, means for increasing the passage resistance, for example,
By providing a portion having a reduced flow path area in a part of the short circuit path to increase the passage resistance, it is possible to prevent the oscillating combustion while suppressing a decrease in the thermal efficiency of the heat exchanger.

According to the seventh aspect of the present invention, even when the acoustic natural frequency of the device changes under the installation conditions of the extension pipe or the like, the length of the short-circuit path is changed to prevent the oscillating combustion. Can be achieved.

According to the eighth aspect of the invention, by adjusting the passage resistance of the short-circuit path, during ignition or the like where vibration combustion is liable to occur, the passage resistance is reduced to suppress vibration combustion. Occasionally, vibration resistance can be prevented while increasing the passage resistance to minimize the decrease in the thermal efficiency of the heat exchanger.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a heater according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a heater according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a heater according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a heater according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram of a heater according to a fifth embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional heater.

[Explanation of symbols]

 Reference Signs List 11 electromagnetic pump (fuel supply device) 12 blower fan (combustion air supply device) 13 burner section 14 combustion cylinder 15 heat exchanger 16 main exhaust path (exhaust section) 17 short circuit path

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Motohiko Kitamura 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Takashi Nishikawa 1006 Kadoma Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Takanobu Fujimoto 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F term (reference) 3K070 AB01 AB14

Claims (8)

[Claims] 1. A fuel supply device for supplying fuel, a combustion air supply device for supplying combustion air, a burner for mixing and burning fuel and combustion air, and communicating with the burner to continue combustion. A combustion tube that guides the combustion gas to the downstream side, a heat exchanger that communicates with the combustion tube and guides the combustion gas to the downstream side while exchanging heat, and an exhaust unit that discharges the combustion gas out of the device. The combustor consists of a main exhaust path communicating with the heat exchanger and a short-circuit path that leads directly to the main exhaust path without passing through the heat exchanger. 2. A fuel supply device for supplying fuel, a combustion air supply device for supplying combustion air, a burner for mixing fuel and combustion air for combustion, and communicating with the burner to continue combustion. A combustion tube that guides the combustion gas to the downstream side while flowing, a heat exchanger that communicates with the combustion tube and guides the combustion gas to the downstream side while exchanging heat, and an exhaust unit that discharges the combustion gas to the outside of the machine. A combustor in which the exchanger includes a main path having a long flow path to the exhaust section and a short-circuit path having a short flow path to the exhaust section with respect to the main path. 3. A heat exchanger formed of a plurality of stages of plate-type heat exchangers, wherein a main path for guiding combustion gas to an exhaust portion via all stages of plate-type heat exchangers, 3. The combustor according to claim 2, further comprising a short-circuit path that does not pass through at least one or more plate-type heat exchangers. 4. A heat exchanger comprising a two-stage plate heat exchanger, wherein an upstream plate heat exchanger near a burner is divided into two chambers, and one of the chambers is provided with combustion gas from the burner. And a connection for guiding the combustion gas to the second-stage plate heat exchanger as a main path, and the other room receives the combustion gas from the second-stage plate heat exchanger. The combustor according to claim 2 or 3, further comprising an inlet portion that connects the fuel cell and a connection portion that guides the combustion gas to the exhaust portion, and a short-circuit path through which the combustion gas can flow is provided between the two chambers. 5. The short-circuit path is provided with means for increasing passage resistance, and the flow rate of the combustion gas passing through the short-circuit path is made smaller than the flow rate of the combustion gas passing through the main path.
A combustor according to any one of the preceding claims. 6. The combustor according to claim 1, wherein a portion having a reduced flow path area is provided in a part of the short circuit path to increase the passage resistance. 7. The combustor according to claim 1, wherein a passage resistance is adjusted by changing a length of a portion having a small flow path area provided in a part of the short circuit path. . 8. The combustor according to claim 1, wherein means for varying the flow path area is provided in a part of the short-circuit path to adjust the path resistance.