JP2006292316A - Heat exchanger and combustion device provided therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger capable of suitably miniaturizing the whole body or reducing a manufacturing cost while keeping high heat exchange efficiency. <P>SOLUTION: The heat exchanger HT comprises a can body 2 and a plurality of heat exchange tubes 40 provided in a plurality of stages in the can body 2. An area closer to the upstream side in the combustion gas advancing direction of the area where the plurality of heat exchange tubes 40 are provided in the can body 2 is set as a sensible heat recovering area S1, while an area closer to the downstream side in the combustion gas advancing direction therefrom is set as a latent heat recovering area S2. At least a part located in the latent heat recovering area S2 of the plurality of heat exchange tubes 40 is made of a material having acid resistivity, and a combustion gas arresting part 5 formed of a member having acid resistivity and preventing latent heat-unrecovered combustion gas from advancing to and contacting with an inner circumferential surface 20a surrounding the latent heat recovering area S2 of the circumferential wall 20 of the can body 2 is provided in the can body 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat exchanger used for recovering heat from combustion gas, and a combustion apparatus such as a hot water supply apparatus provided with the heat exchanger.

  As a conventional traditional heat exchanger, a copper tube (water tube) for heat exchange is arranged in a cylindrical copper can, and water as a heat medium is supplied to the tube. There is something that was made. When the combustion gas generated by the combustor is introduced into the can, the water is heated by the heat exchange action between the combustion gas and the water in the pipe, thereby producing hot water. The can body and the heat exchanging tube section are both made of copper. However, since copper is easy to process and its raw material costs are relatively low, the manufacturing cost of the entire heat exchanger is also low. It is suitable for reducing.

  On the other hand, in recent years, a so-called latent heat recovery type heat exchanger has been proposed and tends to be widely used (see, for example, Patent Document 1). This type of latent heat recovery type not only recovers sensible heat from the combustion gas, but also recovers latent heat from the combustion gas (more precisely, water vapor in the combustion gas). Is possible. However, when latent heat recovery is performed from the combustion gas, water vapor in the combustion gas is condensed and a lot of drains (condensed water) are generated. In general, this drain has a strong acidity of about PH3 absorbing sulfur oxides, nitrogen oxides and the like in the combustion gas. For this reason, if the heat exchanger for recovering latent heat is made of copper, each part of the heat exchanger may be easily corroded due to the drain.

  Therefore, as a means for constructing a latent heat recovery type heat exchanger in the past, a sensible heat recovery heat exchanger and a latent heat recovery heat exchanger are formed separately, and the former is inexpensive. Means are used for making the latter made of stainless steel having acid resistance while making it made of copper. According to such means, for the heat exchanger for sensible heat recovery, its manufacturing cost can be reduced, while for the heat exchanger for latent heat recovery, even if an acidic drain occurs, It is possible to prevent each part from easily corroding due to this.

  However, in the prior art, two heat exchangers for recovering sensible heat and for recovering latent heat are separately manufactured and combined. Therefore, the whole structure which combined these two heat exchangers was complicated, and there existed a problem that the manufacturing cost became expensive. Moreover, in order to combine two heat exchangers, there also existed a problem that the whole became large.

JP 2000-161789 A

  The present invention has been conceived under such circumstances, and is a heat exchanger that has high heat exchange efficiency and can be suitably reduced in overall size and manufacturing cost. It is an object of the present invention to provide a combustion apparatus including the same.

  In order to solve the above problems, the present invention takes the following technical means.

  The heat exchanger provided by the first aspect of the present invention includes a can body having a cylindrical peripheral wall portion, and a plurality of heat exchangers that are provided in a plurality of stages in the can body and into which a medium for heat exchange is supplied. And a combustion gas introduced into the can body or generated in the can body so as to pass through the gaps of the plurality of heat exchange tube sections. Among the regions where the plurality of heat exchange tube parts in the can body are provided, the region closer to the combustion gas traveling direction is the sensible heat recovery region. On the other hand, the region downstream of the combustion gas traveling direction than this is a latent heat recovery region, and the plurality of heat exchanging tube parts have at least a portion positioned in the latent heat recovery region. The inside of the can is made of an acid-resistant member. And a combustion gas blocking portion that prevents the combustion gas not recovered with latent heat from advancing and contacting the inner peripheral surface surrounding the latent heat recovery region of the peripheral wall portion of the can body is provided. It is characterized by that.

  According to such a structure, since it is set as the structure which can collect | recover sensible heat and latent heat from combustion gas, heat exchange efficiency can be improved. On the other hand, the combustion gas blocking portion provided in the can body prevents the combustion gas that has not been recovered from latent heat from advancing and contacting the inner peripheral surface surrounding the latent heat recovery region in the peripheral wall portion of the can body. The drain is prevented from being generated and attached on the inner peripheral surface. Therefore, even if the entire can body is made of, for example, copper, an inexpensive material that does not have acid resistance, the can body can be prevented from being easily corroded. According to the present invention, unlike the prior art, there is no need to combine a copper can body and a stainless steel can body, and the can body may be, for example, only one copper can body. Therefore, according to the present invention, it is possible to appropriately reduce the manufacturing cost and reduce the overall size while improving the heat exchange performance. Of the plurality of heat exchange tube parts, the latent heat recovery region part and the constituent members of the combustion gas blocking part all have acid resistance, so these parts are caused by the acidic drain. It does not corrode easily.

  In a preferred embodiment of the present invention, the combustion gas blocking portion opposes the peripheral wall portion so as to form a heat insulating space portion between the can body and the peripheral wall portion of the can body, and the width direction of the can body or A loop-shaped wall portion surrounding the periphery of the central portion so as to prevent the combustion gas from proceeding from the radially central portion toward the heat insulating space, and upstream of the heat insulating space in the direction of combustion gas flow And a closing portion that closes the opening on the side.

  According to such a configuration, the loop-shaped wall portion and the closed portion serve to prevent combustion gas that has not been recovered from latent heat from entering the heat insulation space portion, and the inner peripheral surface of the peripheral wall portion of the can body. The generation of a drain on the top is appropriately prevented. Moreover, the heat insulation space portion serves to prevent the heat of the combustion gas from escaping to the outside through the peripheral wall portion of the can body, and is suitable for further improving the heat exchange efficiency. Further, the heat insulation space portion prevents the loop-shaped wall portion and the closed portion from becoming as low as the outside air temperature. It is also suitable for preventing the flow from these portions toward the peripheral wall portion of the can body.

  In a preferred embodiment of the present invention, a plurality of fins having acid resistance are provided in a portion located in the latent heat recovery region of the plurality of heat exchange tube portions, and the loop shape is provided. The wall portion includes the plurality of fins.

  According to such a configuration, since latent heat recovery using a plurality of fins is possible, it is more preferable to increase the heat exchange efficiency while reducing the size of the entire heat exchanger. Since it is configured using fins, the configuration is reasonable.

  In a preferred embodiment of the present invention, all or a part of the plurality of fins have a bent plate portion facing an inner peripheral surface of the peripheral wall portion of the can body by bending an end portion thereof. These bent plate portions are connected to each other, so that at least a part of the loop-shaped wall portion is formed.

  According to such a configuration, a part of the combustion gas blocking portion is rationally configured using a structure in which both ends of a plurality of fins are bent, and the manufacturing cost is reduced by reducing the total number of parts. It is suitable for making.

  In a preferred embodiment of the present invention, a plate-like member joined to the end portions of the plurality of fins so as to close gaps between the end portions of the plurality of fins is provided. It constitutes at least part of the loop-shaped wall.

  According to such a configuration, it is possible to appropriately configure the combustion gas blocking portion by closing the gap between the end portions by the plate-like member without bringing the end portions of the plurality of fins into contact with each other. It is suitable for reducing the manufacturing cost.

  In a preferred embodiment of the present invention, an acid-resistant member or coating laminated on the inner peripheral surface so as to cover the inner peripheral surface surrounding the latent heat recovery region in the peripheral wall portion of the can body. A covering layer made of a substance is provided, and the combustion gas blocking portion includes the covering layer.

  Even with such a configuration, combustion gas does not come into contact with the inner peripheral surface of the peripheral wall portion of the can body that surrounds the latent heat recovery region, thereby eliminating the possibility of a drain being generated on the inner peripheral surface. It is possible to achieve the intended effect of the present invention with a simple configuration.

  A combustion apparatus provided by the second aspect of the present invention is a combustion apparatus having a combustor and a heat exchanger that recovers heat from combustion gas generated by the combustor, wherein the heat exchange is performed. The heat exchanger provided by the first aspect of the present invention is used as the heat exchanger.

  According to such a configuration, the same effect as described for the heat exchanger provided by the first aspect of the present invention can be obtained.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  1-5 has shown an example of the hot water supply apparatus with which this invention was applied, and its principal part. As clearly shown in FIG. 1, the hot water supply apparatus A of the present embodiment includes a combustor 1, a heat exchanger HT, a bottom casing 3, and a silencer 19. This hot water supply apparatus A is a reverse combustion system, and the combustion gas generated in the combustor 1 passes downward in the heat exchanger HT and enters the bottom casing 3, and then upwards in the bottom casing 3. After making a U-turn, the sound enters the silencer 19 and is then discharged to the outside through the exhaust port 19a of the silencer 19 as exhaust gas.

  The combustor 1 uses oil such as kerosene as fuel, and injects the fuel downward from the spray nozzle 10 and ignites it with a spark plug 12 for combustion. Fuel oil is supplied to the spray nozzle 10 from an oil tank (not shown) via a fuel supply unit 15. The fuel supply unit 15 includes an electromagnetic pump, an electromagnetic valve 15a, an oil supply pipe 15b, and the like. On the can body 11 of the combustor 1, there is provided a blower fan 13 that sends combustion air downward into the can body 11, and the combustion air is provided around the spray nozzle 10 and the region below it. It enters in the combustion cylinder 14 which was made. The combustion cylinder 14 has a plurality of vent holes on its peripheral wall, and plays a role of promoting mixing of the sprayed oil and the combustion air by using the combustion air as a swirl flow in the combustion cylinder 14. .

  The heat exchanger HT includes a can body 2, a water pipe 4, and a combustion gas blocking unit 5. The can body 2 is made of copper, has a peripheral wall portion 20 having a rectangular prismatic shape, for example, and is placed on the bottom casing 3. The upper opening 21a of the can body 2 is closed by the combustor 1 so that a part of the combustor 1 enters the can body 2, and the upper portion in the can body 2 is a combustion chamber for fuel. It also has a configuration that also serves as. However, this invention is not limited to this, The combustion part of the combustor 1 may be formed in the exterior of the can body 2, and combustion gas may be introduced in the can body 2 from this combustion part.

  The water pipe 4 is configured by using a plurality of stainless steel pipes so that the whole has acid resistance, and the water pipe 4 penetrates the peripheral wall portion 20 of the can body 2 in the horizontal direction and is arranged in a plurality of stages in the vertical direction. The tube part 40 for heat exchange is provided. Among the plurality of tube portions 40, the plurality of upper tube portions 40a serve to recover sensible heat from the combustion gas. In the can body 2, a region where the plurality of tube portions 40 a are provided is a sensible heat recovery region S 1. The plurality of lower tube portions 40b play a role of recovering latent heat from the combustion gas, and a region where the plurality of tube portions 40b are provided is a latent heat recovery region S2.

  The plurality of tube portions 40a and 40b include a plurality of fins 41 and 42, and heat recovery efficiency is enhanced. However, the heat recovery capacities of the plurality of fins 41 and the tube body part 40a are limited, and the specification that does not generate a drain in the sensible heat recovery region S1 during the normal operation of the hot water supply apparatus A, or the generation of drain Is designed to avoid as much as possible. The fins 41 are made of, for example, copper from the viewpoint of cost reduction, but may be made of stainless steel. On the other hand, with respect to the plurality of fins 42 and the tube body portion 40b, it is preferable to recover as much residual heat as possible that has not been recovered by the plurality of fins 41 and the tube body portion 40a, and there is no limitation as described above. The plurality of fins 42 are made of stainless steel.

  As clearly shown in FIG. 2, the combustion gas blocking portion 5 covers the lower inner peripheral surface 20 a surrounding the latent heat recovery region S <b> 2 in the peripheral wall portion 20 of the can body 2. It is a part which prevents combustion gas from advancing and contacting 20a. The combustion gas blocking unit 5 is configured using a plurality of fins 42. More specifically, the plurality of fins 42 are plate-like that are arranged at regular intervals in the longitudinal direction of the tube body portion 40b, except for one fin 42a located at the left end of FIG. A bent plate portion 420 having a substantially L-shaped cross section is formed at both ends of the plate. The bent plate portions 420 of the adjacent fins 42 are in contact with each other so as not to generate a gap between them, and are joined using a technique such as brazing. Since the bent plate portion 420 is joined in this manner, the outer peripheral edge portions of the plurality of fins 42 are formed of the plurality of bent plate portions 420 and the two fins 42a and 42b located at the left end and the right end in FIG. Constitutes a loop-shaped wall portion 51 connected in series. The loop-shaped wall portion 51 is a portion that prevents the combustion gas that has traveled to the region surrounded by the wall portion 51 from flowing out of the region, and the lower inner peripheral surface 20a of the can body 2. Are opposed to each other with a heat insulating space 52 as a gap.

  In the upper part of the heat insulating space 52, a closed portion 53 that closes the upper opening 52a of the heat insulating space 52 is provided. As shown in FIGS. 4 and 5, the closing portion 53 is configured by, for example, inserting a frame-shaped member 53 ′ into the upper opening 52 a and joining them, and the material thereof is a ceramic having acid resistance, Or stainless steel. The member 53 ′ does not need to be a frame-shaped single part, and a plurality of non-frame-divided members can also be used. Further, when the width of the heat insulation space 52 is made small, for example, a thin stainless steel plate is used as the member 53 ′, and the stainless steel plate is made to enter the heat insulation space 52 so as to close the upper opening 52a. May be.

  The plurality of tubular body portions 40b are connected in series by connecting adjacent ones using a U-shaped short tube 43. The plurality of tube portions 40a are also connected in series in the same manner. As shown in FIG. 1, in this heat exchanger HT, the water supplied from the outside to the water inlet 44a flows into the plurality of tube parts 40b through the pipe part 45a, and then passes through the pipe part 45b. It flows into the plurality of tube portions 40a, then passes through the piping portion 45c, reaches the hot water outlet 44b, and is supplied to the outside. If relatively low-temperature water that has not yet been heated is supplied to the plurality of tube portions 40b, it is advantageous for increasing the heat recovery amount in the latent heat recovery region S2 and increasing the heat exchange efficiency. Become. However, the way of water flow to the water pipe 4 is not limited to this.

  The bottom casing 3 has, for example, a substantially rectangular parallelepiped box shape, and has two upper openings 30 a and 30 b communicating with the lower opening of the can 20 and the lower opening of the silencer 19. As described above, the bottom casing 3 is dropped from the latent heat recovery region S2 of the heat exchanger HT in addition to the role of making the U-turn the combustion gas that has passed through the heat exchanger HT and leading it to the silencer 19. It also plays a role of receiving the drain and guiding it to the outside. More specifically, the bottom wall portion 31 of the bottom casing 3 is provided with a discharge port 32 for discharging the drain flowing on the bottom wall portion 31 to the outside. Although the bottom wall portion 31 is shown as being substantially horizontal in the drawing, it is preferable that the bottom wall portion 31 is inclined so that the height is closer to the discharge port 32 as a means for promoting the flow of the drain to the discharge port 32. Yes. The bottom casing 3 has acid resistance, and is made of, for example, stainless steel. The drain discharged from the discharge port 32 is sent to a neutralizer (not shown) to be neutralized. The neutralizer has a configuration in which, for example, a synthetic resin container is filled with a neutralizing agent such as calcium carbonate. The silencer 19 is provided with a sound absorbing material such as glass wool in its interior, and plays a role in reducing exhaust noise.

  Next, the operation of the hot water supply apparatus A will be described.

  First, when the combustor 1 is driven to generate combustion gas, the combustion gas travels downward in the can body 2, passes through the sensible heat recovery region S1, and then proceeds to the latent heat recovery region S2. Since sensible heat and latent heat are recovered from the combustion gas using a plurality of tube portions 40a and 40b, the heat exchange efficiency is high, which is suitable for energy saving.

  The combustion gas blocking unit 5 blocks the combustion gas that has just passed through the sensible heat recovery region S1, that is, the combustion gas that has not been recovered from latent heat, from traveling toward the lower inner peripheral surface 20a of the can body 2. Specifically, as shown by an arrow N <b> 1 in FIG. 2, the combustion gas is prevented from proceeding from above with respect to the inside of the heat insulating space 52 by the closing portion 53. Further, as indicated by the arrow N2, the loop-like wall portion 51 prevents the combustion gas that has entered between the tube portions 40b or between the fins 42 from traveling toward the heat insulating space portion 52. For this reason, combustion gas does not contact the lower inner peripheral surface 20a of the can 2 directly, and no acidic drain is generated on the lower inner peripheral surface 20a. Therefore, there is no problem that the lower inner peripheral surface 20a corrodes in a short period due to the acidic drain. Note that the lower opening 52b of the heat insulating space 52 is open, but the combustion gas that goes into the heat insulating space 52 from the lower opening 52b is combustion gas from which latent heat has already been recovered, This is not a factor for generating a drain on the peripheral surface 20a.

  The heat insulating space 52 also exhibits an effect of suppressing the heat of the combustion gas from being transmitted to the lower inner peripheral surface 20a and escaping from the can body 2 to the outside. Therefore, it is possible to relatively increase the amount of heat recovered by the plurality of tube portions 40b, thereby further increasing the heat exchange. Moreover, when the heat insulation space part 52 plays the role as a heat insulation layer, the effect | action which prevents the loop-shaped wall part 51 from becoming the low temperature comparable as the surrounding wall part 20 of the can body 2, for example is also acquired. If the loop-shaped wall portion 51 becomes low temperature, a lot of drains are likely to be generated in this portion. For example, when a slight gap is generated between the plurality of bent plate portions 420, for example. The drain may enter the heat insulating space 52 from this portion. On the other hand, in this embodiment, such a fear can be appropriately eliminated.

  In the latent heat recovery region S2 of the heat exchanger HT, a large amount of acidic drain is generated on the surfaces of the plurality of tube portions 40b and the fins 42, and they are all materials having acid resistance. It does not corrode easily. In addition, since the drain drops on the bottom wall portion 31 of the bottom casing 3 and is discharged to the outside through the discharge port 32, it is also appropriately avoided that the drain remains in the bottom casing 3. Since the bottom casing 3 serves as a drain receiving member and as a guide member, it is not necessary to separately provide a dedicated member for receiving the drain separately from the bottom casing 3, and the entire configuration can be simplified. This is also suitable.

  As described above, in the hot water supply apparatus A of the present embodiment, high heat exchange efficiency can be achieved by recovering sensible heat and latent heat from the combustion gas, while the heat exchanger HT is made of one copper. It is possible to make the manufacturing cost low. Further, since the combustion gas blocking section 5 is provided in the heat exchanger HT, the can body 2 is appropriately prevented from being corroded by preventing the drain from adhering to the can body 2. There are no problems caused by the use of copper. The combustion gas blocking unit 5 is configured by effectively using a plurality of fins 42 and is easy to manufacture. Therefore, the presence of the combustion gas blocking unit 5 greatly increases the overall cost of the heat exchanger HT. There is no such thing as pushing up. In addition, since the heat exchanger HT is of a single can type, it is advantageous to reduce the overall size of the heat exchanger HT, and hence the overall size of the hot water supply device A.

  6 to 8 show other examples of the present invention. In these drawings, elements that are the same as or similar to those in the above embodiment are given the same reference numerals as in the above embodiment.

  In the configuration shown in FIG. 6, although a substantially L-shaped bent plate portion 420 is formed at each end of the plurality of fins 42, a gap s <b> 1 is formed between the plurality of bent plate portions 420. Has been. On the other hand, a stainless steel plate 54 is overlapped and joined to the outer surfaces of the plurality of bent plate portions 420, and the plate 54 closes the gap s1. Therefore, the loop-shaped wall 51 in the present embodiment is configured to include the plate material 54.

  Also in the configuration of the present embodiment, the combustion gas that has not been recovered with latent heat is appropriately prevented from entering the heat insulating space 52. On the other hand, since it is not necessary to join the bent plate portions 420 of the fins 42 without gaps, it is more preferable to reduce the manufacturing cost of the heat exchanger.

  7 and 8, a covering layer 55 made of a material having acid resistance is laminated on the lower inner peripheral surface 20a of the can body 2, and the combustion gas blocking portion 5A is provided with this covering layer. 55 is comprised. The covering layer 55 is configured by, for example, joining a thin plate member 55 made of stainless steel to the lower inner peripheral surface 20a, or coating a ceramic or other material having corrosion resistance.

  In the present embodiment, since the lower inner peripheral surface 20a of the can body 2 is covered with the coating layer 55, the combustion gas not recovered with latent heat does not directly contact the lower inner peripheral surface 20a. A drain does not occur and adhere to the inner peripheral surface 20a. Although a drain may be generated on the surface of the coating layer 55 itself, if the coating layer 55 is in close contact with the lower inner peripheral surface 20a, the drain is prevented from flowing on the lower inner peripheral surface 20a. It is possible to appropriately prevent the corrosion of the lower inner peripheral surface 20a. Of course, since the coating layer 55 has acid resistance, this portion is not easily corroded. The combustion gas blocking unit 5A of the present embodiment has a very simple configuration and is easy to manufacture as compared with the combustion gas blocking unit 5 of the above-described embodiment. It is suitable for further reducing the manufacturing cost.

  The present invention is not limited to the embodiment described above. The specific configuration of each part of the heat exchanger and the combustion apparatus according to the present invention can be varied in design in various ways.

  The combustion gas blocking part referred to in the present invention is provided so as to prevent the combustion gas not recovered with latent heat from advancing and contacting the inner peripheral surface surrounding the latent heat recovery region in the peripheral wall part of the can. What is necessary is just to be provided so that the area | region surrounding the area | region for sensible heat recovery may be covered. However, from the viewpoint of saving the constituent members of the combustion gas blocking portion and reducing the manufacturing cost, it is preferable to provide only the portion surrounding the latent heat recovery region.

  Although it is necessary to comprise a combustion gas prevention part with the member which has acid resistance, as a specific example of the material of the member, titanium etc. are mentioned as examples other than stainless steel and ceramic, for example. Further, the surface may be coated with a substance having acid resistance, and the inner part thereof may be made of a material not having acid resistance. This also applies to the case where the pipe for recovering latent heat and the fins provided in the pipe are provided with acid resistance.

  The can body is not limited to copper, but may be a copper alloy or other materials. For the plurality of heat exchange tube parts, it is sufficient that at least the part where the drain is generated due to the recovery of latent heat is made of a material having acid resistance such as stainless steel, and other parts are cheaper than stainless steel, for example. Copper or other materials may be used. However, if all of the heat exchange tube parts are made of, for example, stainless steel, there is an advantage that pitting corrosion or the like can be made difficult to occur when acidic well water or the like is passed through the heat exchange tube parts. can get. The specific number and number of tube sections for heat exchange, and which of them are for sensible heat recovery or latent heat recovery, are appropriately selected according to the thermal power of the combustor. These are specific matters, and their specific values are not specified.

  The heat exchanger according to the present invention is not limited to the reverse combustion method in which the combustion gas advances downward, and can be used in a method different from this. However, when the combustion gas advances downward as in the above-described embodiment, the lower region in the can body is used as a latent heat recovery region, and the drain generated in this region can be easily discharged below the can body. It becomes. Therefore, considering the ease of drain discharge and the like, it is considered optimal to use the combustion gas so as to advance downward.

  The combustion apparatus according to the present invention can be configured as various types of hot water supply apparatuses such as an instantaneous general hot water supply apparatus, a hot water supply apparatus for a bath, and a hot water supply apparatus for heating. It can also be configured as a combustion device. As the combustor, various types such as a gas combustor can be used instead of the oil combustor.

It is a partial cross section schematic front view which shows an example of the hot-water supply apparatus with which this invention was applied. It is principal part sectional drawing of the hot-water supply apparatus shown in FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a principal part cross-sectional perspective view of the heat exchanger used for the hot-water supply apparatus shown in FIG. It is a principal part disassembled cross-sectional perspective view of the heat exchanger shown in FIG. It is a principal part cross-sectional perspective view which shows the other example of this invention. It is principal part sectional drawing which shows the other example of this invention. It is VIII-VIII sectional drawing of FIG.

Explanation of symbols

A Water heater (combustion device)
HT Heat exchanger S1 Sensible heat recovery area S2 Latent heat recovery area 1 Combustor 2 Can body 4 Water pipe 5, 5A Combustion gas blocking section 40 Heat exchange tube section 42 Fin 51 Loop-shaped wall section 52 Thermal insulation space section 53 Blocking portion 54 Plate material 55 Covering layer 420 Bent plate portion

Claims (7)

A can body having a cylindrical peripheral wall portion, and a plurality of heat exchange tube portions provided in a plurality of stages in the can body and supplied with a heat exchange medium therein,
A heat exchanger configured such that combustion gas introduced into the can or generated in the can progresses through the gaps of the plurality of heat exchange tube parts,
Among the regions where the plurality of heat exchanging tube portions in the can are provided, the region closer to the combustion gas traveling direction upstream is a sensible heat recovery region, while the combustion gas traveling direction is more than this. The downstream area is a latent heat recovery area,
The plurality of heat exchange tube parts are made of a material having at least a portion located in the latent heat recovery region having acid resistance,
The can body is constituted by an acid-resistant member, and the combustion gas that has not been recovered with latent heat is in contact with the inner peripheral surface surrounding the latent heat recovery region of the peripheral wall portion of the can body. A heat exchanger characterized in that a combustion gas blocking part for blocking is provided.   The combustion gas blocking portion opposes the peripheral wall portion so as to form a heat insulating space portion between the can body and the peripheral wall portion of the can body, and the heat insulating space from a portion near the center in the width direction or radial direction of the can body. A loop-shaped wall that surrounds the periphery of the portion near the center so as to prevent the combustion gas from proceeding toward the portion, and a blocking portion that closes the opening on the upstream side in the combustion gas flow direction of the heat insulating space, The heat exchanger according to claim 1, comprising: Of the plurality of heat exchange tube parts, a portion located in the latent heat recovery region is provided with a plurality of fins having acid resistance,
The heat exchanger according to claim 2, wherein the loop-shaped wall portion includes the plurality of fins.   All or a part of the plurality of fins has a bent plate portion opposed to the inner peripheral surface of the peripheral wall portion of the can body by bending an end portion thereof, and the bent plate portions are mutually connected. The heat exchanger according to claim 3, wherein at least a part of the loop-shaped wall portion is configured by being connected.   A plate-like member joined to the end portions of the plurality of fins so as to close gaps between the end portions of the plurality of fins, and the plate-like member covers at least a part of the loop-shaped wall portion; The heat exchanger according to claim 3, which is configured. Of the peripheral wall portion of the can body, provided with a covering layer made of an acid-resistant member or a coating material laminated on the inner peripheral surface so as to cover the inner peripheral surface surrounding the latent heat recovery region,
The heat exchanger according to claim 1, wherein the combustion gas blocking unit includes the coating layer. A combustion device comprising a combustor and a heat exchanger that recovers heat from the combustion gas generated by the combustor,
A combustion apparatus using the heat exchanger according to any one of claims 1 to 6 as the heat exchanger.

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