JP2014145549A - Combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a latent heat recovery type combustion device, for example, that including an exhaust gas collection cylinder capable of reducing noise without using a sound absorber, that including an inexpensive exhaust gas collection cylinder of a simple structure having a volume larger than that of a latent heat recovery heat exchanger.SOLUTION: A combustion device 1 includes: a sensible heat recovery heat exchanger 7 recovering sensible heat of a combustion gas; a latent heat recovery heat exchanger 8 recovering latent heat of a combustion exhaust gas; and an exhaust collection cylinder 10 disposed at a downstream side of the latent heat recovery heat exchanger 8 and discharging the combustion exhaust gas after heat exchange by the latent heat recovery heat exchanger 8, to a front part. The exhaust gas collection cylinder 10 includes: a rear-side projecting portion 10b projecting to a rear part with respect to a rear end portion of the latent heat recovery heat exchanger 8; and a guide member 42 for guiding at least a part of the combustion exhaust gas introduced from an exhaust port 14 formed at an upper part of the latent heat recovery heat exchanger 8, to a side of the rear-side projecting portion 10b, and the exhaust gas collection cylinder 10 is constituted to invert the combustion exhaust gas flowing to the rear part at the rear-side projecting portion 10b as an exhaust flow directing to the front part.

Description

  The present invention relates to a combustion apparatus, and more particularly to a latent heat recovery type combustion apparatus having an exhaust collecting cylinder that can reduce noise without using a sound absorbing material such as glass wool.

  2. Description of the Related Art Conventionally, a combustion apparatus that combusts a gas has been widely spread as a heat source apparatus such as a hot water supply apparatus and a heating device. This type of combustion apparatus takes in combustion air from the outside with a blower fan, mixes the combustion air and gas, burns it in a combustor composed of a plurality of burners, and then uses combustion heat exhaust gas and water in a heat exchanger. Heat is exchanged between the two to heat the water and supply it as hot water.

  By the way, in the above-mentioned combustion apparatus, not only those equipped with a heat exchanger that uses sensible heat of combustion gas, but also a latent heat recovery type that uses the latent heat of combustion exhaust gas after sensible heat recovery to improve thermal efficiency. Have also been put to practical use. For example, in the combustion apparatus of Patent Document 1, a sensible heat recovery heat exchanger (main heat exchanger) that mainly recovers sensible heat of combustion exhaust gas and a downstream side of the sensible heat recovery heat exchanger are installed. A structure including a latent heat recovery heat exchanger (auxiliary heat exchanger) for recovering mainly latent heat of combustion exhaust gas is disclosed.

  Further, the latent heat recovery heat exchanger of Patent Document 1 is installed in an L shape in a side view along the upper surface side and the rear surface side of the sensible heat recovery heat exchanger. The exhaust passage incorporating the heat exchanger for recovering latent heat is composed of two passages partitioned by a partition plate, and ends of the two passages are connected by a U-shaped connecting portion. In addition, an exhaust passage enlarged portion for reducing noise caused by combustion exhaust gas is formed.

JP 2004-245515 A

  However, in the structure of the combustion apparatus of Patent Document 1, the noise caused by the combustion exhaust gas passing through the latent heat recovery heat exchanger is reduced by the exhaust passage enlarged portion of the connecting portion provided in the middle of the latent heat recovery heat exchanger. Although reduced, the combustion exhaust gas after passing through the heat exchanger for recovering latent heat is discharged directly to the outside, so that there is a problem that noise due to the combustion exhaust gas cannot be sufficiently reduced. In the first place, the combustion apparatus of Patent Document 1 is costly because the latent heat recovery heat exchanger has a complicated structure in order to reduce noise.

  In a conventional combustion apparatus, there is a case where an exhaust collecting cylinder having a sound absorbing material is attached to an exhaust port for exhausting combustion gas to the outside. However, in the case of a latent heat recovery type combustion apparatus such as Patent Document 1, if an exhaust collecting cylinder is attached to the exhaust outlet on the downstream side of the latent heat recovery heat exchanger, the drain generated when recovering the latent heat becomes acidic. Therefore, there is a problem that the sound absorbing material corrodes due to the acidic drain adhering to the sound absorbing material of the exhaust collecting cylinder. Therefore, in the case of a latent heat recovery type combustion apparatus, there is a problem that it is impossible to reduce the exhaust noise by incorporating the sound absorbing material into the exhaust collecting cylinder.

  It is an object of the present invention to provide a latent heat recovery type combustion apparatus having an exhaust collecting cylinder capable of reducing noise without using a sound absorbing material, and having a simple structure and a lower cost than a latent heat recovery heat exchanger. It is to provide one having an exhaust collecting cylinder that becomes large.

  The combustion apparatus of claim 1 is a combustion apparatus comprising a sensible heat recovery heat exchanger that recovers sensible heat of combustion exhaust gas, and a latent heat recovery heat exchanger that recovers latent heat of combustion exhaust gas, In the combustion apparatus provided with an exhaust collecting cylinder installed downstream of the latent heat recovery heat exchanger and exhausting the combustion exhaust gas after heat exchange by the latent heat recovery heat exchanger forward, the exhaust collecting cylinder At least a part of the combustion exhaust gas introduced from the projecting portion projecting rearward from the rear end portion of the latent heat recovery heat exchanger and the exhaust port opened above the latent heat recovery heat exchanger. And a guide member for guiding the projecting portion toward the projecting portion, wherein the exhaust collecting cylinder is configured to invert the combustion exhaust gas flowing rearward at the projecting portion so that the exhaust gas flows forward. It is said.

  According to a second aspect of the present invention, there is provided a combustion apparatus according to the first aspect, wherein the guide member has an inclined portion extending in an upwardly inclined manner toward the rear at least at a lower portion of the exhaust collecting cylinder.

  According to the first aspect of the present invention, the exhaust collecting cylinder is introduced from the projecting portion projecting rearward from the rear end portion of the latent heat recovery heat exchanger and the exhaust port opened above the latent heat recovery heat exchanger. And a guide member for guiding at least a part of the combustion exhaust gas toward the projecting portion, and the exhaust collecting cylinder inverts the combustion exhaust gas flowing rearward at the projecting portion so that the exhaust gas flows forward. Thus, two passages having different passage lengths can be formed inside the exhaust collecting cylinder by the protrusion and the guide member. For this reason, if the exhaust gas flow toward the front and the exhaust flow toward the rear of the combustion exhaust gas are recombined, the exhaust sound cancels out at the time of the merge due to the canceling action opposite to the resonance action. At least, the exhaust noise of the combustion exhaust gas can be reduced.

  In addition, since the volume of the exhaust collecting cylinder can be increased by providing the protruding portion, the flow rate of the combustion exhaust gas introduced into the exhaust collecting cylinder from the exhaust port is lowered, and the sound pressure level of the exhaust sound is reduced. The combustion exhaust gas is rectified and the exhaust noise of the latent heat recovery type combustion device can be reduced without using a sound absorbing material. A simple structure, low cost, and low noise can be realized. The exhaust flow passage toward the rear has a structure in which the combustion exhaust gas is reversed inside the protruding portion, so that the passage length is remarkably increased and the damping action can be enhanced.

  According to the second aspect of the present invention, the guide member has the inclined portion extending in the upward inclined shape toward the rear at least at the lower portion of the exhaust collecting cylinder, so that the combustion exhaust gas flowing in from the exhaust port passes through the lower side of the inclined portion. It is possible to reliably guide the rearward projecting portion, and it is possible to reliably guide the combustion exhaust gas inverted by the projecting portion forward through the upper side of the inclined portion.

It is a schematic block diagram of the combustion apparatus which concerns on the Example of this invention. It is a perspective sectional view of the superstructure of a combustion device. It is a longitudinal cross-sectional view of the upper structure of a combustion apparatus. It is a perspective view of an exhaust collecting cylinder. It is a perspective view of the upper structure of a combustion apparatus main body.

  Hereinafter, embodiments of the present invention will be described based on examples.

Initially, the whole structure of the combustion apparatus 1 is demonstrated easily.
As shown in FIG. 1, the combustion apparatus 1 is applied as a heat source machine such as a hot water supply apparatus or a heating device, and includes various pipes such as a combustion apparatus body 2, a water inlet pipe 3 a, a hot water outlet pipe 3 b, and a drain pipe 3 c. Most of these are covered with a thin steel plate casing (not shown).

  A blower fan 5 for supplying combustion air is provided below the case member 4 of the combustion apparatus main body 2. A burner unit 6 for burning fuel gas is built in the lower part inside the case member 4. The burner unit 6 includes, for example, 10 burners.

  Inside the case member 4, a sensible heat recovery heat exchanger 7 that recovers mainly sensible heat of the combustion gas in order from the bottom, and mainly the latent heat of the combustion exhaust gas after the recovery of sensible heat, on the upper side of the burner unit 6. A latent heat recovery heat exchanger 8 is provided. An exhaust collecting cylinder 10 for discharging combustion exhaust gas to the outside is provided on the upper portion of the case member 4.

  In the combustion apparatus 1, the incoming water supplied from the inlet pipe 3 a is heated by the latent heat of the combustion exhaust gas in the latent heat recovery heat exchanger 8, and then supplied to the sensible heat recovery heat exchanger 7 for the sensible heat recovery. After being heated by the heat exchanger 7, it is supplied to the tapping pipe 3b. A tray 9 for receiving drain (condensed water) generated by the latent heat recovery is provided immediately below the latent heat recovery heat exchanger 8, and the drain recovered in the tray 9 passes through the drain pipe 3c and is neutralized (illustrated). To be neutralized.

Here, the upper structure of the combustion apparatus main body 2 and the exhaust collecting cylinder 10 unique to the present application attached to the upper structure will be described.
As shown in FIG. 2, FIG. 3, and FIG. 5, the upper part of the combustion apparatus main body 2 is constituted by a heat exchange can 11 that has a built-in latent heat recovery heat exchanger 8 and is a part of the case member 4. . In the rear portion of the bottom plate 11a of the heat exchange can 11 is formed an inlet 12 through which combustion exhaust gas after sensible heat recovery by the sensible heat recovery heat exchanger 7 is introduced. The tray 9 described above is formed on the front portion of the bottom plate 11a of the heat exchange can 11.

  The top plate 11b of the heat exchange can body 11 is formed with a paragraph portion 13 stepped downward. The paragraph 13 is formed in a rectangular shape that is slightly longer in the left-right direction in plan view. An exhaust port 14 of the latent heat recovery heat exchanger 8 is formed in the front portion of the paragraph portion 13. The exhaust port 14 is formed in a substantially rectangular shape that opens upward and extends in the left-right direction. The exhaust port 14 has an area of about ¼ to ½ times the area of the paragraph portion 13 in plan view (see FIG. 5). An annular mounting plate portion 15 is mounted on the top surface of the top plate 11b, and the exhaust collecting cylinder 10 is mounted through the mounting plate portion 15 so as to cover the top surface side of the top plate 11b and both front and rear side portions thereof.

  On the inner side of the heat exchange can 11, vertical rectifying plates 16 a and 16 b are attached to the vicinity of the introduction port 12 and the vicinity of the exhaust port 14. The combustion gas flowing in from the inlet 12 is heat-exchanged by the rectifying plates 16a and 16b while passing through the latent heat recovery heat exchanger 8, and the combustion exhaust gas after the latent heat recovery by the latent heat recovery heat exchanger 8 is exhausted. It flows into the exhaust collecting cylinder 10 from the port 14.

Next, the exhaust collecting cylinder 10 unique to the present application will be described.
As shown in FIGS. 2 to 4, the exhaust collecting cylinder 10 is installed on the downstream side of the latent heat recovery heat exchanger 8 and on the upper end side of the case member 4, and after the latent heat recovery by the latent heat recovery heat exchanger 8. These combustion exhaust gases are collected and discharged from the front of the combustion apparatus 1 into the atmosphere.

  The exhaust collecting cylinder 10 is configured as a rectangular parallelepiped box-shaped body made of a stainless steel plate, and forms a collecting cylinder main body 21 that forms an exhaust passage 23 for combustion exhaust gas that rises through the latent heat recovery heat exchanger 8; An exhaust top 22 for exhausting combustion exhaust gas flowing through the exhaust passage 23 of the collective cylinder body 21 to the outside is mainly configured.

  The collective cylinder main body 21 includes a front plate portion 24, a rear plate portion 25, a left plate portion 26, a right plate portion 27, a top plate portion 28, and a bottom plate portion 29, and is configured as a flat box-shaped body. A discharge port 24a is formed in the front plate portion 24 of the collective cylinder body 21 so as to extend in the left-right direction, and an exhaust top 22 protruding forward and having an open central portion is attached to the peripheral portion of the discharge port 24a. Yes.

  A rectangular opening 29a is formed in the bottom plate 29 from the front part to the rear part, and an opening member 35 to be described later is mounted so as to cover the rectangular opening 29a. On the peripheral edge of the rectangular opening 29a, an inclined peripheral wall 29b extending in a downwardly inclined manner toward the center of the opening is formed.

  Inside the left and right plate portions 26 and 27, a pair of flange portions 42d at both left and right end portions of a guide member 42 to be described later are fixed. Mounting flange portions 19a are provided on the outer sides of the rear plate portion 25 and the left and right plate portions 26 and 27, respectively. The exhaust collecting cylinder 10 is attached to the attachment plate portion 15 of the case member 4 via an attachment flange portion 19a and a plurality of screws 19b.

  Further, the exhaust collecting cylinder 10 includes an exhaust introduction portion 31 (an exhaust passage expanding portion 32 having a larger passage cross-sectional area than the exhaust port 14 and an exhaust passage) through which combustion exhaust gas is introduced from the exhaust port 14 of the latent heat recovery heat exchanger 8. Exhaust passage reducing means 33 for reducing the exhaust gas), and an exhaust dividing means 41 for dividing the combustion exhaust gas flowing into the exhaust introduction portion 31 into the front and rear.

Next, the exhaust introduction part 31 will be described.
As shown in FIGS. 2 to 4, the exhaust introduction part 31 is provided on the bottom plate part 29 side and is for introducing combustion exhaust gas from the exhaust port 14 to the exhaust passage 23 in the exhaust collecting cylinder 10.
The exhaust introduction part 31 includes an exhaust passage expanding part 32 communicating with the exhaust port 14 opened above the latent heat recovery heat exchanger 8, and an exhaust passage reducing part installed so as to cover the upper surface of the exhaust passage expanding part 32. Means 33.

Next, the exhaust passage expanding portion 32 will be described.
As shown in FIGS. 2 to 5, the exhaust passage enlarged portion 32 is an inner region of the stage portion 13 of the top plate 11 b of the heat exchange can body 11 and the inclined peripheral wall portion 29 b of the collective cylinder body 21, and It is comprised by the area | region divided by the inclination surrounding wall part 29b and the opening member 35. As shown in FIG. The exhaust passage enlarged portion 32 has a passage cross-sectional area that is about 2 to 3 times the passage cross-sectional area of the exhaust port 14, and has a height that is about 1/4 to 1/3 times that of the collective cylinder body 21. doing. The exhaust passage expanding portion 32 has a function of expanding and depressurizing the combustion exhaust gas introduced from the exhaust port 14 to reduce the flow velocity.

Next, the exhaust passage reducing means 33 will be described.
As shown in FIGS. 2 to 4, the exhaust passage reducing means 33 is mounted over the entire area from the front part to the rear part of the bottom plate part 29 so as to cover the rectangular opening 29 a. The exhaust passage reduction means 33 includes an opening member 35 having a plurality of openings 36. The opening member 35 is made of a so-called punching metal having a rectangular shape in plan view. The exhaust passage expanding portion 32 and the exhaust passage 23 inside the collective cylinder main body 21 are communicated with each other through an opening member 35.

  The plurality of openings 36 have a plurality of small-diameter holes 36a (for example, about 2 mm in diameter) formed in a plurality of rows and columns (for example, a pitch of about 3 mm) and a slit-shaped large opening 36b. The opening member 35 has a function of narrowing and rectifying (squeezing) the flow of the combustion exhaust gas in the exhaust passage expanding portion 32 by the plurality of small diameter holes 36a.

  Thus, the combustion exhaust gas introduced from the exhaust port 14 into the exhaust introduction part 31 has its flow velocity lowered by the exhaust passage expanding part 32 and the sound pressure level of the exhaust sound is lowered. Is rectified by passing through a plurality of openings 36 (a plurality of small diameter holes 36 a) constituting the exhaust passage reducing means 33, and the uneven flow velocity distribution is alleviated, and the combustion exhaust gas enters the exhaust passage 23 of the collective cylinder body 21. Can be introduced uniformly, so that the exhaust noise of the combustion exhaust gas can be reduced.

Next, the exhaust gas dividing means 41 will be described.
As shown in FIGS. 2 to 4, the exhaust gas introduced from the exhaust port 14 opened above the latent heat recovery heat exchanger 8 is exhausted to the exhaust introduction part 31 toward the front part of the exhaust collecting cylinder 10. Exhaust gas splitting means 41 is provided for splitting into a flow and an exhaust flow towards the rear. The exhaust dividing means 41 includes an opening member 35 constituting the exhaust passage reducing means 33 and a closing portion 42a which is a part of a guide member 42 for partially closing the plurality of openings 36. Yes.

  Next, the structure related to the exhaust division of the opening member 35 described above will be described. The opening member 35 includes a front portion 35a extending forward from the exhaust port 14 in a plan view, and a portion directly above the exhaust port 14. 35b and a rear portion 35c extending rearward from the exhaust port 14.

  The plurality of openings 36 in the front portion 35a and the directly upper portion 35b are composed of a plurality of small diameter holes 36a. On the upper surface side of the upper part 35b, a closing part 42a for closing the plurality of small-diameter holes 36a of the upper part 35b is provided in contact with the entire length in the left-right direction. The small-diameter hole 36a is blocked.

  The plurality of openings 36 in the rear portion 35c include a plurality of small diameter holes 36a and a large opening 36b that is provided in a portion separated from the exhaust port 14 and has an opening area larger than that of the small diameter hole 36a. The large opening 36b is formed in a rectangular shape in plan view that is elongated in the left-right direction, and divides the rear portion 35c forward and backward. By forming the large opening 36b, more combustion exhaust gas can flow to the rear portion 35c. The large opening 36b has a function of preventing an increase in exhaust resistance even when impurities contained in the combustion exhaust gas are clogged in the small diameter hole 36a.

  The closed portion is configured such that the opening area formed by the plurality of small diameter holes 36a in the front portion 35a and the opening area formed by the plurality of small diameter holes 36a and the large opening portions 36b in the rear portion 35c have a balanced distribution of, for example, about 2: 8. The position 42a is set. That is, the exhaust gas dividing means 41 is set so that the ratio of the rear exhaust flow is larger than the front exhaust flow of the combustion exhaust gas.

  Thus, the exhaust gas dividing means 41 divides the combustion exhaust gas introduced from the exhaust port 14 into the exhaust gas introduction portion 31 into a front exhaust flow toward the front portion of the exhaust collecting cylinder 10 and a rear exhaust flow toward the rear portion. . During the division of the combustion exhaust gas, the combustion exhaust gas of the front exhaust flow and the rear exhaust flow can be rectified by the plurality of small-diameter holes 36a, and the passage length through which the front exhaust flow and the passage length through which the rear exhaust flow flows are different. Since the length is set, an exhaust noise canceling action can be obtained at the junction of the two exhaust flows, so that the exhaust noise of the combustion exhaust gas can be reduced.

Next, the internal structure of the exhaust collecting cylinder 10 will be described.
As shown in FIGS. 2 to 4, the exhaust collecting cylinder 10 includes a front protruding portion 10 a protruding forward from the front end portion of the latent heat recovery heat exchanger 8 and a rear end portion of the latent heat recovery heat exchanger 8. And a rear projecting portion 10b projecting rearward (corresponding to a projecting portion), and is introduced into the exhaust collecting cylinder 10 from an exhaust port 14 opened above the latent heat recovery heat exchanger 8. A guide member 42 is provided for guiding at least a portion of the combustion exhaust gas toward the rear protrusion 10b.

  The front protrusion 10a has a length that is about ¼ to 倍 times the length in the front-rear direction of the heat exchange can 11 with the built-in latent heat recovery heat exchanger 8, and the rear protrusion 10b Similarly, the heat exchange can 11 has a front-rear length that is about ¼ to ４ times the length in the front-rear direction. That is, the exhaust collecting cylinder 10 has a length of about 1.4 to 2 times the longitudinal length of the heat exchange can body 11, and has a height of about 7/10 to 7/8 of the heat exchange can body 11. doing.

  The guide member 42 has a rectangular plate-shaped closing portion 42a and an inclination that is formed integrally with a rear end portion of the closing portion 42a and extends in an upward inclined manner toward the rear in at least the lower half portion (lower portion) of the exhaust collecting cylinder 10. Part 42b, a curved part 42c formed integrally with the rear end part of the inclined part 42b and curved forward, and a pair of flange parts integrally formed at the left and right ends of the inclined part 42b and bent upward 42d. The guide member 42 is fixed to the collective tube body 21 via a pair of flange portions 42d so as to partially close the plurality of small diameter holes 36a of the opening member 35 by the closing portion 42a.

  As shown in FIG. 3, the exhaust passage 23 in the exhaust collecting cylinder 10 passes through the front short portion 23 a that forms the front exhaust flow that passes through the front portion 35 a and flows to the front protruding portion 10 a, and the rear portion 35 c. It consists of two paths: an exhaust long passage 23b that forms a rear exhaust flow that flows toward the rear protrusion 10b and flows around the guide member 42 and flows toward the front protrusion 10a. Since the exhaust long passage 23b has a structure in which the combustion exhaust gas is reversed inside the rear protrusion 10b, the exhaust passage is significantly longer than the short exhaust passage 23a, so that the exhaust flow attenuation rate is improved.

  That is, the exhaust collecting cylinder 10 reverses the combustion exhaust gas that has flowed rearward after passing through the lower side of the guide member 42, passes through the upper side of the guide member 42, and moves forward. In addition to the exhaust flow, the combustion exhaust gas flowing forward from the rear protrusion 10b and the combustion exhaust gas flowing directly forward are merged and mixed in the front protrusion 10a to form an exhaust flow toward the exhaust top 22. Is configured to do.

  In this way, if the passage lengths of the two passages of the exhaust passage 23 (the passage through which the front exhaust flow flows and the passage through which the rear exhaust flow flows) are made different, the front exhaust flow and the rear exhaust flow of the combustion exhaust gas merge again. In addition, since the exhaust noise cancels out due to the canceling action opposite to the resonance action, the exhaust noise of the combustion exhaust gas can be reduced. Further, since the exhaust collection cylinder 10 has a larger volume than the latent heat recovery heat exchanger 8 (heat exchange can body 11), the combustion exhaust gas introduced into the exhaust collection cylinder 10 from the exhaust port 14 expands. As a result, the flow velocity decreases, the gas pressure of the combustion exhaust gas decreases, and the combustion exhaust gas is rectified to reduce the exhaust noise of the combustion exhaust gas. Via the rear protrusion 10b, the length of the passage through which the rear exhaust flow flows can be increased to enhance the damping action.

Next, the operation and effect of the combustion apparatus 1 of the present invention will be described.
First, in the case member 4, the rising combustion exhaust gas after the sensible heat and latent heat are recovered through the sensible heat recovery heat exchanger 7 and the latent heat recovery heat exchanger 8 is recovered as latent heat. From the exhaust port 14 of the heat exchanger 8 for heat to the exhaust introduction part 31 of the exhaust collecting cylinder 10. At this time, the combustion exhaust gas flowing into the exhaust passage expanding portion 32 of the exhaust introduction portion 31 is expanded, the flow velocity is reduced, and the gas pressure is also reduced.

  Next, the combustion exhaust gas passes through the front part 35a of the opening member 35 through the front part 35a of the opening member 35 and the rear part 35c of the opening member 35 by the closing part 42a of the guide member 42. It is divided into a rear exhaust flow flowing through the exhaust long passage 23b. At this time, the combustion exhaust gas passes through the opening member 35 constituting the exhaust passage reducing means 33, so that the combustion exhaust gas is rectified and flows into the exhaust collecting cylinder 10 so that the flow velocity distribution becomes uniform.

  Inside the exhaust collecting cylinder 10, the combustion exhaust gas of the front exhaust flow flowing through the exhaust short passage 23a flows toward the front protruding portion 10a after passing through the front portion 35a. The combustion exhaust gas of the rear exhaust flow flowing through the exhaust long passage 23b flows along the lower side of the inclined portion 42b of the guide member 42 after passing through the rear portion 35c, and flows toward the rear protruding portion 10b. It is reversed at the portion 10b and flows forward along the upper side of the inclined portion 42b.

  Next, the combustion exhaust gas of the front exhaust flow and the rear exhaust flow is merged and mixed in the front protrusion 10a. When this combustion exhaust gas is mixed, the exhaust sound of the front exhaust flow and the exhaust sound of the rear exhaust flow cancel each other out due to the canceling action. The combustion exhaust gas mixed inside the front protrusion 10 a is discharged from the exhaust top 22 to the outside of the exhaust collecting cylinder 10.

  As described above, the exhaust collecting cylinder 10 includes the rear projecting portion 10b that projects rearward from the rear end portion of the latent heat recovery heat exchanger 8, and the exhaust port that opens above the latent heat recovery heat exchanger 8. 14 and a guide member 42 for guiding at least a part of the combustion exhaust gas introduced from 14 toward the rear protruding portion 10b. The exhaust collecting cylinder 10 allows the combustion exhaust gas flowing rearward to flow into the rear protruding portion 10b. In this way, the exhaust flow is directed in the forward direction, so that two passages having different passage lengths can be formed in the exhaust collecting cylinder 10 by the rear protrusion 10b and the guide member 42. For this reason, if the exhaust gas flow toward the front and the exhaust flow toward the rear of the combustion exhaust gas are recombined, the exhaust noise cancels out at the time of the merge due to the canceling action opposite to the resonance action. At least, the exhaust noise of the combustion exhaust gas can be reduced.

  Further, by providing the rear protruding portion 10b, the volume of the exhaust collecting cylinder 10 can be increased, so that the flow rate of the combustion exhaust gas introduced into the exhaust collecting cylinder 10 from the exhaust port 14 is reduced. The sound pressure level of the exhaust sound is reduced and the combustion exhaust gas is rectified. Therefore, the exhaust sound of the latent heat recovery type combustion apparatus 1 can be reduced without using a sound absorbing material. A simple structure, low cost, and low noise can be realized. The exhaust flow passage toward the rear has a structure in which the combustion exhaust gas is reversed inside the rear protruding portion 10b, so that the passage length is remarkably increased and the damping action can be enhanced.

  Further, since the guide member 42 has an inclined portion 42b extending in an upwardly inclined manner toward the rear at least at the lower part of the exhaust collecting cylinder 10, the combustion exhaust gas flowing in from the exhaust port 14 is rearwardly passed through the lower side of the inclined portion. The side protrusion 10b can be reliably guided, and the combustion exhaust gas reversed by the rear protrusion 10b can be reliably guided forward through the upper side of the inclined portion 42b.

An example in which the embodiment is partially changed will be described.
[1] The opening member 35 of the above embodiment is made of punching metal. However, the opening member 35 is not particularly limited to the punching metal, and may be made of a net-like member. A plurality of burring holes may be directly formed in 29, and the member constituting the opening member 35 or the structure of the opening member 35 can be appropriately changed.

[2] The shape of the guide member 42 in the above embodiment is merely an example, and can be appropriately changed as long as a part of the combustion exhaust gas is guided toward the rear protruding portion 10b.

[3] In addition, those skilled in the art can implement the present invention in various forms with various modifications without departing from the spirit of the present invention, and the present invention includes such modifications. It is.

  The latent heat recovery type combustion apparatus of the present invention can be used to make hot water required in homes, factories, and various facilities.

DESCRIPTION OF SYMBOLS 1 Combustion apparatus 7 Sensible heat recovery heat exchanger 8 Latent heat recovery heat exchanger 10 Exhaust collecting cylinder 10b Rear side protrusion part 14 Exhaust port 31 Exhaust inlet part 32 Exhaust path expansion part 33 Exhaust path reduction means 35 Opening member 35a Front part 35b Directly upper part 35c Rear part 36 Opening part 36a Small diameter hole 36b Large opening part 41 Exhaust gas dividing means 42 Guide member 42a Closing part 42b Inclined part

Claims (2)

A combustion apparatus comprising a sensible heat recovery heat exchanger for recovering sensible heat of combustion gas and a latent heat recovery heat exchanger for recovering latent heat of combustion exhaust gas, wherein the combustion apparatus is downstream of the latent heat recovery heat exchanger In a combustion apparatus provided with an exhaust collecting cylinder for exhausting the combustion exhaust gas installed on the side and after heat exchange by the latent heat recovery heat exchanger forward,
The exhaust collecting cylinder includes at least a protruding portion protruding rearward from a rear end portion of the latent heat recovery heat exchanger, and combustion exhaust gas introduced from an exhaust port opened above the latent heat recovery heat exchanger. A guide member for guiding a part toward the protrusion,
The exhaust gas collection cylinder is configured to invert the combustion exhaust gas flowing rearward at the projecting portion into an exhaust flow directed forward.   2. The combustion apparatus according to claim 1, wherein the guide member has an inclined portion that extends in an upwardly inclined manner toward the rear at least in a lower portion of the exhaust collecting cylinder.