JP2003090532A - Combustion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion apparatus which causes almost no external leak of a noise generated in an exhaust manifold without using a sound absorber. SOLUTION: The exhaust manifold 5 disposed in an upper section of a combustion case 6 of the combustion apparatus 1 has an outer cover member 15 at the outside of a coating cover 14. The combustion apparatus 1 comprises an upper cavity 28a and a side face cavity 28b constituted between the cover 14 and the member 15. A combustion gas generated from a combustion section 3 is introduced from a lower opening of the cover 14 into the inside thereof, and collides. A vibrating component of the combustion gas is almost attenuated at the cover 14, and a part of the component is propagated to the member 15 side. The component propagated to the member 15 is further dispersed at the member 15, the vibrating component to be leaked to the exterior is small, and hence the noise to be leaked from the apparatus 1 is extremely small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device, and more particularly, to a combustion device characterized by an exhaust stack.

[0002]

2. Description of the Related Art In recent years, a water heater 100 that is widely and generally used has a combustion device 101 built therein and an exhaust pipe 104 for discharging combustion gas generated in the combustion device 101, as shown in FIG. Have. Hereinafter, a water heater conventionally used will be described. In the following, positional relationships such as up, down, left and right are shown with reference to the posture shown in FIG.

The combustion apparatus 101 is a substantially rectangular parallelepiped, and a combustion section 103 for combusting fuel is provided inside a combustion case 102 having openings on its upper and lower surfaces. An exhaust pipe 104 is provided at an end portion on the upper surface side of the combustion case 102, and a blower 109 is attached to an opening portion on the lower surface side. The combustion gas generated by burning the fuel in the combustion unit 103 rises upward in the combustion case 102, and
Introduced in 04.

The exhaust pipe 104 is a box-shaped body having openings on the lower surface and the left side surface, and is attached so as to cover the end portion on the upper surface side of the combustion case 102. Combustion section 1
The combustion gas generated at 03 is introduced from the opening on the lower surface side of the exhaust stack 104, collides with the upper surface and side surfaces of the exhaust stack 104 inside the exhaust stack 104, and changes the flow direction.
It is discharged from the exhaust port 105 provided on the left side surface of the.

In the combustion device 101, a combustion noise in the combustion section 103, a wind noise caused by driving the blower 109, and the like are generated during combustion driving. Further, in the exhaust stack 104 of the combustion device 101, an exhaust passage noise is generated when the combustion gas passes through. The exhaust sound is generated by the combustion gas colliding with the upper surface and the side surface of the exhaust pipe 104, causing the exhaust pipe 104 to vibrate, and the vibration of the exhaust pipe 104 propagating to the air outside the exhaust pipe 104. Therefore, in the water heater 1, the glass wool 107 formed in a felt shape in order to suppress the exhaust passage noise is attached to the upper surface and the side surface of the exhaust pipe 104 by the mesh-like locking member 108, whereby the vibration accompanying the collision of the combustion gas is generated. Is absorbed.

[0006]

The glass wool 107 used as a sound absorbing material for the exhaust stack 104 is made by laminating short fibers such as ultrafine glass fibers with a binder or the like. The short fibers constituting the glass wool 107 are easily separated from the glass wool 107 main body and scattered,
When it adheres to the human body, it causes itchiness and other discomfort. for that reason,
To attach the glass wool 107 to the exhaust stack 104,
There is a problem that the burden on the human body of the worker is large and the work efficiency is inevitably low.

The glass wool 107 has a large variation in quality such as density and thickness, and when it is attached to the exhaust pipe 104, the thickness of the glass wool 107 varies depending on the attachment position. Therefore, the exhaust stack 104 has uneven sound absorbing performance for noise generated in the combustion device 101.

The inside of the exhaust stack 104 is heated by the combustion gas and becomes extremely hot. The glass wool 107 attached inside the exhaust stack 104 is often laminated using an organic binder. Therefore, when the glass wool 107 is exposed to a high-temperature atmosphere for a long period of time, short fibers such as glass fibers and lumps of glass wool 107 are separated and scattered due to the deterioration of the binder, so that a sufficient sound absorbing effect cannot be exhibited. Further, if short fibers or lumpy glass wool 107 scatters in the water heater and blocks the exhaust outlet, etc., the combustion performance of the water heater 100 is deteriorated, and in the worst case, the water heater 100 fails.

Further, in the glass wool 107, if it contains water, the sound absorbing effect is significantly deteriorated. Therefore, the water heater 1
However, if the glass wool 107 is exposed to wind and rain, or is placed in a high humidity atmosphere, the glass wool 107 absorbs water, and there is a problem in that it cannot exert a sufficient sound absorbing effect. Therefore, an object of the present invention is to provide a combustion device that hardly leaks noise generated in the exhaust stack to the outside without using a sound absorbing material such as glass wool.

[0010]

Therefore, in the present invention, the technical means described below were taken. The present invention has a combustion case, a combustion section incorporated in the combustion case, and an exhaust pipe provided at an end of the combustion case, and the exhaust pipe communicates with a cover and a cover that covers the end of the combustion case. The combustion case axis intersects with the exhaust port axis, and the combustion gas generated in the combustion section flows through the combustion case and reaches the exhaust stack where it collides with the cover and changes its direction. In the combustion apparatus exhausted from, the cover lid does not allow the flow of combustion gas, and an outer lid member is provided outside the cover lid to cover substantially the entire area of the cover lid, and between the outer lid member and the cover lid. Is a combustion device characterized by being hollow and having no internal components.

When the combustion gas collides with the cover portion, the vibration component of the combustion gas is dispersed into various components. That is, a part of the oscillating component of the combustion gas is reflected by the cover portion toward the inside of the combustion case. Further, the vibration component of the combustion gas vibrates the cover portion. Still another vibration component penetrates the cover portion and is transmitted to the outer lid member side. Therefore, since the vibration component of the combustion gas is attenuated in the cover portion, the vibration component that passes through the cover portion and is transmitted to the outer lid member side is very small.

The vibration component transmitted through the cover lid collides with the outer lid member, and the same phenomenon as when the combustion gas collides with the cover lid occurs. That is, the vibration component that collides with the outer lid member is reflected or transmitted by the outer lid member or vibrates the outer lid member. When the vibration component that penetrates the outer lid member and the vibration component that vibrates the outer lid member propagate to the outside air, noise is generated. However, since most of the vibration component of the combustion gas is attenuated in the cover portion, the noise generated by the combustion device is extremely small.

Further, according to the above structure, since the combustion gas cannot flow through the cover lid portion, the combustion gas does not directly collide with the outer lid member. Therefore, the vibration component of the combustion gas is propagated to the outer lid member after being largely attenuated in the cover portion. The vibration component propagated to the outer lid member is greatly attenuated in the cover portion and is extremely small, so that the noise leaked from the combustion device is small.

Further, in the combustion apparatus of the present invention, the outer lid member covers substantially the entire cover portion. That is, the vibration component of the combustion gas is significantly attenuated when passing through the cover portion, and most of it collides with the outer lid member. Therefore, the vibration component leaking from the outer lid member is greatly attenuated, and the noise leaking from the combustion device is extremely small.

Further, in the above-described combustion apparatus, the outer lid member and the cover lid portion may be in contact with each other at the outer peripheral portion.

The contact portion where the outer lid member and the cover portion are in contact with each other has higher rigidity than other non-contact portions, and the natural frequency is different. Therefore, the amplitude of the vibration generated when the combustion gas collides with the contact portion differs from the amplitude of the vibration generated when the combustion gas collides with the non-contact portion. The vibration generated in the contact part and the vibration generated in the non-contact part are
Since the amplitude and the period are different, when these vibration components collide, they are attenuated. Therefore, according to the present invention, the vibration component that vibrates the cover portion and the outer lid member is attenuated, so that the noise leaked to the outside of the combustion device is small.

In the above-described combustion apparatus, the outer lid member can cover 80% or more of the surface area of the cover portion.

According to the above-mentioned structure, most of the vibration component of the combustion gas collides with both the cover and the outer cover member, so that it is greatly attenuated. Therefore, the vibration component leaked to the outside of the combustion device is small, and the noise leaked to the outside is extremely small.

Further, in the above-described combustion apparatus, the difference in the thickness of the cavity between the outer lid member and the covering lid portion is within 10% in 60% or more of the area covered by the outer lid member. It is also possible.

According to this structure, the outer lid member and the covering lid portion are substantially parallel to each other and are not in contact with each other in 60% or more of the area where the outer lid member covers the covering lid portion. Therefore, the vibration of the cover portion itself is hardly transmitted to the outer lid member. That is, most of the vibration component transmitted to the outer lid member is transmitted through the cover portion.
It is a very small vibration component. Therefore, there is little noise leakage to the outside of the combustion device.

The above-mentioned combustion apparatus may have an outer box, and the combustion case and the exhaust stack may be housed in the outer box.

According to this structure, the vibration component transmitted through the outer lid member collides with the outer box, so that the vibration component leaking to the outside of the outer box is greatly attenuated. Therefore, leakage of noise to the outside of the combustion device is further suppressed.

Further, in the above-mentioned combustion apparatus, the outer lid member and the cover portion may be made of different materials.

According to this structure, the natural frequencies of the outer lid member and the cover portion that form the exhaust pipe are different throughout. Therefore, the vibration component of the combustion gas that vibrates the outer lid member and the cover portion is efficiently damped.

Further, at least a part of the wall surface constituting the outer lid member and / or the cover portion may be curved.

The amplitude of the vibration generated by the combustion gas colliding with the curved wall surface (curved wall surface) is different from the amplitude of the vibration generated by the combustion gas collision with the non-curved wall surface (non-curved wall surface). Since the vibrations generated on the curved wall surface and the vibrations generated on the non-curved wall surface have different amplitudes and periods, they are significantly attenuated when these vibration components collide with each other. Therefore, according to the present invention, the vibration component of the cover lid portion and the outer lid member is attenuated, so that the noise leaked to the outside of the combustion device is further reduced.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is a sectional view of a combustion apparatus of the present invention.
FIG. 2 is an exploded perspective view of an exhaust stack of the combustion device of FIG.
FIG. 3 is a cross-sectional view of the exhaust stack of FIG.

In FIG. 1, reference numeral 1 indicates a combustion apparatus of the present invention. The combustion device 1 is roughly divided into a blower unit 2, a combustion unit 3, a heat exchange unit 4, and an exhaust stack 5. The combustion section 3 is contained inside a substantially rectangular parallelepiped combustion case 6 having an open top surface. The exhaust stack 5 is provided so as to cover the open upper surface of the combustion case 6. The blower unit 2 also has a blower 7 such as a sirocco fan or a turbo fan, in which the fan is rotated by the rotation of the motor. Blower 8 of blower 7
Are directly attached to the air introduction holes 9 provided on the lower surface of the combustion case 6. When the transmitter 7 is driven, the outside air is supplied to the combustion unit 3 from the blower port 8.

The combustion section 3 has a plurality of burner members 10 and is built in the combustion case 6. Burner member 10
Is the air introduced through the air introduction hole 9 and the burner member 10.
A fuel gas supplied from a fuel nozzle 11 provided in the vicinity of is mixed and burned to generate combustion gas.

A heat exchange section 4 is provided on the upper side of the combustion section 3 and is incorporated in the combustion case 6. Heat exchange section 4
Is a quadrangular cylinder through which the combustion gas generated in the burner member 10 passes. Inside the heat exchange unit 4, a large number of fins 12 are vertically arranged at a predetermined interval, and a bent hot water supply pipe 13 is attached so as to penetrate the fins 12. The high-temperature combustion gas generated in the combustion section 3 passes through the gaps of the fins 12 arranged at predetermined intervals. At this time, the thermal energy of the combustion gas is
The heat is converted into the hot water supply pipe 13 via 2. Fin 12
The combustion gas that has passed through moves to the gas downstream side (upper side in the drawing) and is introduced into the exhaust stack 5.

An exhaust pipe 5 is provided on the downstream side of the heat exchange section 4, that is, on the upper end side of the combustion case 6. Exhaust stack 5
Is for deflecting the flowing direction of the combustion gas generated in the combustion unit 3 and passing through the heat exchange unit 4 and rising to the outside, and discharging the combustion gas to the outside of the combustion apparatus 1. That is, the exhaust stack 5
Has an exhaust port 21 communicating with the outside, and the axis X of the combustion case 6 and the axis Y of the exhaust port 21 intersect. The exhaust stack 5 is
The external appearance is a substantially box shape, the cover portion 14 and the outer lid member 15 are provided, and the draining deflecting member 16 is provided inside.

Here, the detailed structure of the exhaust stack 5 will be described with reference to the drawings. FIG. 2 is an exploded perspective view of an exhaust stack used in the combustion device shown in FIG. In addition, in the following description, the positional relationship between the upper, lower, left, right and front is based on the state in which the exhaust pipe 5 is attached to the combustion device 1 as shown in FIG.

The cover 14 is formed by pressing a metal plate such as stainless steel. The cover portion 14 includes a top surface portion 17,
It has side surface portions 18, 19, 20 and has a shape in which the lower surface and the left side surface are opened. The opening portion on the left side surface of the cover portion 14 functions as the exhaust port 21 for the combustion gas. Top part 1
7 is slightly inclined downward near the exhaust port 21.
The side surface portion 20 is curved in an arc shape. Also, the side surface portion 1
Around the circumferences of 8, 19, 20 is provided a flange portion 22a which can be engaged with the end portion of the combustion case 6. A flange portion 22b is provided at the end of the top surface portion 17 on the exhaust port 21 side.

The outer lid member 15 has substantially the same structure as the cover lid portion 14, and is formed by pressing a metal plate such as an aluminum-plated steel plate in a shape along the cover lid portion 14. That is, the outer lid member 15 has the top surface portion 23 and the side surface portions 24, 25, 26, and the top surface portion 17, the side surface portions 18, 1 of the cover lid portion 14 respectively.
It is bent along 9 and 20. Further, the lower surface and the left side surface of the outer lid member 15 are opened. The opening portion 32 on the left side surface is in contact with the exhaust port 21 of the cover portion 14 described above. Around the side surface portions 24, 25, 26, a plurality of joining pieces 27 extending in a direction substantially perpendicular to the side surface portions 24, 25, 26 are provided. The outer lid member 15
Is a press-molded metal plate made of a material different from that of the cover portion 14, but may be made of the same material. Further, the cover portion 14 and the outer lid member 15 are not limited to the aluminum plate, the aluminum-plated steel plate, etc., and may be made of an appropriate material such as heat resistant resin.

As shown in FIG. 2, the cover lid portion 14 is fitted so that the side surface portions 18, 19, 20 of the cover lid portion 14 are fitted to the side surface portions 24, 25, 26 of the outer lid member 15, respectively. Substantially the entire 14 is housed inside the outer lid member 15. The outer lid member 15 may cover only a part of the cover lid portion 14, but the cover lid portion 1 as in the present embodiment.
It is preferable to cover 80% or more of the surface area of No.4.

As shown in FIGS. 3 (a) and 3 (b), a predetermined space is provided between the top surface portion 17 of the cover lid portion 14 and the top surface portion 23 of the outer lid member 15, whereby the upper cavity 28a is formed. Are formed. Further, side surface cavities 28b and 28c are formed between the side surface portions 18 and 19 of the cover lid portion 14 and the side surface portions 24 and 25 of the outer lid member 15, respectively. Further, in the area where the outer lid member 15 covers the cover portion 14, 60% or more of the area covers the upper cavity 28a and the side surface cavities 28b, 28c.
And the difference in thickness is within 10%.

The cover lid portion 14 and the outer lid member 15 are the same as the cover lid portion 1.
The flange portion 22a of No. 4 and the joining piece 27 of the outer lid member 15 are integrated by spot welding. Further, the side surface portion 20 of the cover lid portion 14 and the side surface portion 26 of the outer lid member 15 are fixed and integrated by spot welding, and the cover lid portion 14 and the outer lid member 15 are in contact with each other at the outer peripheral portion. There is. The covering lid portion 14 and the outer lid member 15 are not limited to spot welding, but may be integrated by any method such as seam welding, bolt nuts, rivets, or the like.

The upper cavity 28a and the side cavity 28b,
28c is a cavity constituted by the cover lid portion 14 and the outer lid member 15, and there is no internal component inside. Further, the sound absorbing layer 28 is substantially sealed by the cover lid portion 14 and the outer lid member 15, and even if the combustion gas is introduced into the cover lid portion 14 from the opening of the lower surface, the upper cavity 28a and the side surface cavity 28b,
No combustion gas can enter the 28c.

A drainer deflecting member 16 is fixed to the cover portion 14 of the exhaust stack 5. The draining deflecting member 16 is formed by bending a thin metal plate, and has one end curved to form a deflecting portion 29. In addition, the other end of the drainage deflecting member 16 is bent downward to form the flange portion 3
0 is formed. The drain deflector 16 is provided in the exhaust stack 5.
The rainwater that has entered the inside of the drainage is discharged to the outside, and the rainwater that has entered through the exhaust ports 21 and 32 strikes the draining member 16, travels along the upper surface of the draining member 16, and is discharged to the outside.

The exhaust stack 5 is fixed to the upper end side of the combustion case 6 via a flange 22a. Further, an exhaust top 31 as shown in FIG. 1 is attached to the left end portion of the exhaust pipe 5, the flange portion 22b of the cover lid portion 14 and the flange portion 30 of the draining deflecting member 16. Thereby, the draining deflecting member 16 is firmly positioned.

As shown in FIG. 4, the combustion gas generated in the combustion section 3 and passing through the heat exchange section 4 is covered by the cover section 14.
It is introduced into the exhaust pipe 5 through the opening on the lower surface side of the. The combustion gas introduced into the cover lid portion 14 moves upward in the cover lid portion 14, collides with the top surface portion 17 and the side surface portions 18, 19, 20 which are wall surfaces of the cover lid portion 14, and deflects the moving direction. When the combustion gas collides with the cover portion 14, the vibration component of the combustion gas is propagated to the cover portion 14 side.

The vibration component propagated to the cover portion 14 is dispersed on the wall surface of the cover portion 14. That is, the vibration component propagated to the cover 14 is dispersed into the vibration components a1, b1 and c1. The vibration component a1 is reflected on the wall surface of the cover portion 14 toward the combustion case 6 side. The vibration component b1 is a vibration component that collides with the cover 14 and causes the cover 14 to vibrate. The vibration component c1 is transmitted through the wall surface of the cover 14 and moves to the outer cover member 15 side.

The vibration component a1 reflected to the combustion case 6 side in the cover 14 does not vibrate the outside air of the combustion device 1 and thus does not leak noise to the outside. On the other hand, the cover portion 14
Is a predetermined amplitude w due to the vibration component b1 propagating.
Vibrates at. Further, when the vibration component b1 propagates to the joints A and B between the cover lid portion 14 and the outer lid member 15, the above-mentioned amplitude w
It vibrates with an amplitude of w ', which is different from. This is because the cover lid portion 14 has different rigidity at the joint portions A and B between the cover lid portion 14 and the outer lid member 15, and therefore, in the vicinity of the joint portions A and B, the natural frequency is different from that of the other portions of the cover lid portion 14. Due to the difference. Therefore, when the vibration component of the combustion gas propagates to the cover portion 14, a vibration having an amplitude w and a vibration having an amplitude w ′ are generated, and when these collide, the vibration in the cover portion 14 is significantly damped. Therefore, the noise generated in the cover portion 14 is extremely small.

Further, the vibration component c1 transmitted through the cover portion 14
Propagates to the outer lid member 15. The vibration component propagated to the outer lid member 15 is dispersed on the wall surface of the outer lid member 15 as in the cover portion 14. That is, a part of the vibration component propagated to the outer lid member 15 is reflected toward the cover portion 14 side on the wall surface of the outer lid member 15 (vibration component a2). Part of the vibration component vibrates the outer lid member 15 (vibration component b2), and the remaining vibration component passes through the wall surface of the outer lid member 15 and moves to the outside of the combustion device 1 ( Vibration component c2).

The vibration component c1 transmitted through the cover 14 is largely attenuated because a part of the vibration component of the combustion gas is dispersed on the wall surface of the cover 14. Further, the vibration component c1 collides with the vibration component a2 reflected by the outer lid member 15. Here, the vibration component a2 is reflected by the outer lid member 15, and has a vibration cycle different from that of the vibration component c1. Therefore, most of the vibration component c1 is
It is canceled by the vibration component a2.

The outer cover member 15 vibrates with a predetermined amplitude W by the vibration component b2 which is a part of the vibration component c1 that has passed through the cover portion 14. On the other hand, in the vicinity of the joints A and B, the natural frequency is different from the rigidity of the other parts of the outer lid member, and the natural frequency is different. It vibrates with an amplitude of W '. When the vibration component b2 propagates to the outer lid member 15, vibration of the amplitude W and vibration of the amplitude W ′ are generated and collide with each other.
The vibration of the outer lid member 15 due to the vibration component b2 is extremely small. Further, the vibration component c2 that passes through the outer lid member 15 is the remaining part in which the vibration component a2 and the vibration component b2 are dispersed from the vibration component c1 and is an extremely small vibration component. Since both the vibration and the vibration component c2 of the outer lid member 15 are extremely small, the noise leaked from the outer lid member 15 is very small.

As described above, the outer lid member 15 is
80% or more of the surface area of the cover 14 is covered. Therefore, most of the vibration component of the combustion gas is attenuated in both the cover lid portion 14 and the outer lid member 15 as described above,
The noise leaked from the exhaust stack 5 is small.

Further, as described above, the difference in the thickness of the cavity formed by the outer lid member 15 and the cover lid portion 14 is 60% or more of the area covered by the outer lid member 15 by the outer lid member 15. Is within 10%, and the cover portion 14 and the outer lid member 15
Not in contact with. Therefore, the vibration of the cover 14 itself due to the vibration component b1 hardly propagates to the outer cover member 15. Therefore, most of the vibration component transmitted to the outer lid member 15 is the vibration component c1 transmitted through the cover 14 and attenuated, and the noise leaked from the exhaust pipe 5 is extremely small.

The side surface portion 20 of the cover lid portion 14 and the outer lid member 1
The side portions 26 of No. 5 are both curved. Therefore,
The amplitude of the vibration generated when the combustion gas collides with the curved side surface portions 20, 26 is equal to the amplitude of the top surface portions 17, 23 and the side surface portions 18, 1.
The amplitude of the vibration generated when the combustion gas collides with 9, 24, 25 is different. Therefore, when the vibration components having different amplitudes collide with each other, the vibration components b1 and b2 that vibrate the cover portion 14 and the outer lid member 15 are significantly attenuated, and the noise leaked from the exhaust pipe 5 to the outside is small.

The combustion device 1 is usually housed in the outer box 33 of the water heater. Therefore, the vibration component c2 leaking in the exhaust stack 5 is further attenuated in the outer box 33. Therefore, the water heater using the combustion device 1 hardly leaks noise accompanying the discharge of the combustion gas to the outside during operation.

In the above embodiment, the cover lid portion 14 and the outer lid member 15 are made of different materials, but the material of the outer lid member 15 is the same as the material of the cover lid portion 14. May be. When the cover portion 14 and the outer lid member 15 are made of different materials, their natural frequencies are different. Therefore, the difference between the amplitude of the vibration component c1 transmitted through the cover 14 and the amplitude of the vibration component a2 reflected by the outer lid member 15 is remarkable, and the vibration component c1 can be further attenuated. That is, when the cover lid portion 14 and the outer lid member 15 are made of different materials, noise leaking from the exhaust pipe 5 is further reduced. Further, since a material having a high corrosion resistance is used only in a portion in contact with the combustion gas, and it is not necessary to pay much attention to the corrosion resistance in a portion in which the combustion gas does not contact, it is possible to reduce the cost as a whole. It should be noted that when the cover lid portion 14 and the outer lid member 15 are made of different materials, it is desirable that they can be easily disassembled in consideration of recycling.

Further, in the above embodiment, the exhaust stack 5
Is a cover lid portion 14 and an outer lid member 15 obtained by spot welding a joining piece 27 to the flange portion 22a.
Combustion gas hardly penetrates into 8a and side surface cavities 28b and 28c. In the present invention, the upper cavity 28a and the side surface cavities 28b and 28c need not be hermetically sealed, but it is possible that the combustion gas penetrates into the sound absorbing layer and the vibration component is directly propagated to the outer lid member 15. To prevent
It is desirable to be in a substantially sealed state.

In the above embodiment, the exhaust pipe 5 has the cover portion 14 and the outer cover member 15 integrated in advance and is attached to the upper portion of the combustion case 6, but only the cover portion 14 is attached to the combustion case 6 in advance. Alternatively, the outer lid member 15 may be attached from above the cover lid portion 14. Further, the outer lid member 15 can be separately attached to the exhaust pipe 104 of the conventional combustion device 101. That is, by attaching the outer lid member 15 to the exhaust pipe of the existing combustion apparatus, it is possible to suppress the noise generated in the exhaust pipe.

[0054]

EXAMPLES Examples of the present invention will be described below. FIG. 5 is a combustion device 1 shown in FIG. 1, which is an embodiment of the present invention.
7 is a graph showing a result of measuring noise generated in the combustion device 101 shown in FIG. Also, the combustion device 1
As for the measurement, measurement was performed for the case where the exhaust pipe 5 has a double structure including the cover lid portion 14 and the outer cover member 15, and the case where the exhaust pipe 5 has a single structure including only the cover lid portion 14. In this example, the noise value generated from the combustion devices 1 and 101 was measured by the A characteristic in the frequency range of 0 Hz to 2000 Hz.

The noise value when the exhaust stack 5 of the combustion apparatus 1 has a double structure was lower than the noise value when the exhaust stack 5 had a single structure in almost all frequency ranges. Also, the exhaust stack 5
The noise value in the case of the double structure is equal to or lower than the noise value in the case where the glass wool 107 is stuck inside the exhaust pipe 104 in almost all frequency ranges. That is, the exhaust pipe 5 configured by the cover lid portion 14 and the outer lid member 15.
In the case of adopting, the noise leaking from the combustion device was the lowest.

[0056]

According to the invention described in claim 1, it is possible to reduce the noise leaking from the combustion device without separately providing a sound absorbing material such as glass wool.

According to the second aspect of the present invention, the vibration of the cover lid portion and the outer lid member itself can be suppressed, so that the noise leaking from the combustion device can be further reduced.

According to the third aspect of the present invention, most of the vibration component of the combustion gas collides with both the cover and the outer cover member, so that the vibration component is greatly attenuated. Therefore, the noise leaked to the outside of the combustion device is extremely small.

According to the fourth aspect of the present invention, since the vibration of the cover portion itself is hardly transmitted to the outer lid member, the noise generated when the combustion device is driven is small.

According to the fifth aspect of the present invention, the vibration component leaking from the combustion device is further attenuated in the outer box, so that the noise generation is extremely small.

According to the sixth aspect of the invention, the vibration component can be efficiently damped due to the difference in natural frequency between the outer lid member and the cover portion. Therefore, the noise generated by driving the combustion device is small.

According to the seventh aspect of the present invention, the vibration generated on the curved wall surface and the vibration generated on the non-curved wall surface collide and are damped, so that the noise leaked to the outside of the combustion device is small.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a combustion device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of an exhaust stack used in the combustion device of FIG.

3A is a cross-sectional view of an exhaust stack used in the combustion device of FIG. 1, and FIG. 3B is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a schematic diagram showing how a vibration component propagates in the combustion apparatus shown in FIG.

FIG. 5 is a graph showing measurement results of noise values in the example of the present invention.

FIG. 6 is a sectional view of a conventional combustion device.

[Explanation of symbols]

1 Combustion device 3 Combustion section 5 exhaust stack 6 combustion case 14 Cover 15 Outer lid member 21,32 exhaust port 33 outer box

Claims (7)

[Claims] 1. A combustion case, a combustion section built in the combustion case, and an exhaust pipe provided at an end of the combustion case, the exhaust pipe having a cover portion for covering the end of the combustion case, and an outside. It has a communicating exhaust port, the axis of the combustion case intersects with the axis of the exhaust port, and the combustion gas generated in the combustion section flows through the combustion case to reach the exhaust pipe, collides with the cover lid and changes direction, In the combustion apparatus discharged from the mouth, the cover lid does not allow the flow of combustion gas, and an outer lid member is provided outside the cover lid to cover substantially the entire area of the cover lid, and the outer lid member and the cover lid are Combustion device characterized by the fact that there is no internal component between the spaces. 2. The combustion apparatus according to claim 1, wherein the outer lid member and the cover lid portion are in contact with each other at an outer peripheral portion. 3. The combustion apparatus according to claim 1, wherein the outer lid member covers 80% or more of the surface area of the cover portion. 4. The area of the outer cover member covering the cover portion is 60.
% Or more, the difference in the thickness of the cavity between the outer lid member and the covering lid portion is within 10%, and the combustion device according to any one of 1 to 3 above. 5. A combustion case and an exhaust stack having an outer box,
The combustion apparatus according to any one of claims 1 to 4, wherein the combustion apparatus is housed in the outer box. 6. The combustion apparatus according to claim 1, wherein the outer lid member and the cover portion are made of different materials. 7. The combustion apparatus according to claim 1, wherein at least a part of a wall surface forming the outer lid member and / or the cover portion is curved.