JP2021101129A - Heat exchanger and water heating device equipped with the same - Google Patents

Abstract

To provide a heat exchanger capable of suppressing generation of a large amount of condensed water on the surface of a fin and appropriately eliminating a risk of exhaust air clogging, and a water heating device equipped with the heat exchanger.SOLUTION: A heat exchanger HE includes: a can body 4 which accommodates a heat transfer pipe 5 and a plurality of fins 6, and is positioned sideways so that heating gas advances in a lateral direction inside; and a water-cooled pipe 7 wound around the outer surface of the peripheral wall part 40 of the can body 4. A plurality of notched recesses 61 extending toward a mutual region of a plurality of pipe body parts 50 of the heat transfer pipe 5 from one end part 60 are provided in a region S near the one end part on the upstream side in the flow direction of heating gas of each fin 6. A terminal end of the notched recess 61a located on the upper part side of each fin 6 is located on the upstream side in the flow direction of heating gas of terminal ends of the other notched recesses 61 positioned on the lower part side.SELECTED DRAWING: Figure 3

Description

The present invention relates to a type of heat exchanger using a so-called fin-equipped heat transfer tube, and a water heating device such as a water heater equipped with the heat exchanger.

Specific examples of the water heating device include those described in Patent Documents 1 and 2.
The water heating device described in these documents includes a burner and a heat exchanger that recovers heat from the combustion gas generated by the burner as a heating gas to heat hot water. In the heat exchanger, a heat transfer tube and a plurality of fins joined to the heat transfer tube are arranged inside the can body to which the combustion gas is supplied, and a water cooling tube is provided on the outer surface of the peripheral wall portion of the can body. It is wrapped. This water cooling pipe cools a region of the peripheral wall of the can body near the burner. Therefore, the can body is prevented from being damaged by heat.

In the water heating device as described above, for various reasons such as the conditions of the installation location, the burner and the heat exchanger are placed in a sideways position, and the combustion gas generated from the burner is allowed to travel sideways to be supplied to the heat exchanger. You may want to set it.

However, when the sideways setting is made as described above, a problem to be solved arises as described below.
That is, in the can body of the heat exchanger, the water vapor in the combustion gas is condensed in the portion cooled by the water cooling pipe, and strongly acidic condensed water is generated. This condensed water is generated on the inner surface of the peripheral wall portion of the can body, and the condensed water generated on the inner surface of the upper wall portion of the peripheral wall portion is blown to the downstream side in the combustion gas flow direction by the combustion gas, or is above. By traveling along the inner surface of the wall portion, there is a risk of reaching and adhering to the heat transfer tube and a plurality of fins. Here, if a large amount of condensed water adheres to the fins, the temperature of the fins decreases, so that condensed water is likely to be generated in that portion. As a result, the amount of condensed water generated on the surface of the fin increases.
When such a phenomenon occurs, the amount of corrosion products generated due to the evaporation of condensed water increases, so that the gaps between the plurality of fins are likely to be clogged, and the heat exchanger may become so-called exhaust blockage. .. In order to ensure a smooth flow of combustion gas and to perform efficient heat recovery, it is desired to appropriately eliminate such a risk.

Japanese Patent No. 6411108 Japanese Unexamined Patent Publication No. 5-164402

The present invention has been conceived under the above-mentioned circumstances, and it is possible to suppress the generation of a large amount of condensed water on the surface of the fins and appropriately eliminate the possibility of exhaust blockage. The challenge is to provide a possible heat exchanger and a water heater equipped with the heat exchanger.

In order to solve the above problems, the following technical measures are taken in the present invention.

The heat exchanger provided by the first aspect of the present invention is arranged in a can body in which the heating gas is supplied so as to travel sideways in a sideways posture and inside the can body. A heat transfer tube for recovering heat from the heating gas to heat hot water, a plurality of fins joined to the heat transfer tube, and heating of the peripheral wall portion of the can body more than the plurality of fins. It is a heat exchanger provided with a water cooling tube wound around an outer surface portion on the upstream side in the gas flow direction, and a plurality of tubular body portions constituting the heat transfer tube are vertically high on each of the fins. Penetrating in an arrangement arranged at intervals in the direction, and in the region near one end on the upstream side in the heating gas flow direction of each fin, from the one end toward the inter-regional region of the plurality of tubular parts. A plurality of notch recesses extending are provided, and among these plurality of notch recesses, the end of the notch recess located on the upper side of each fin is from the end of the other notch recess located on the lower side. Is also characterized in that it is located on the upstream side in the heating gas flow direction.

According to such a configuration, the following effects can be obtained.
That is, as described in the column of background technology, in the heat exchanger described above, since the peripheral wall portion of the can body is cooled by the water cooling pipe, condensed water is generated on the inner surface of the peripheral wall portion, and the condensed water is generated. Of these, the condensed water generated on the inner surface of the upper wall portion of the peripheral wall portion may reach the surface portion of each fin and adhere to it. In this case, the condensed water tends to adhere to the region near one end on the upstream side in the heating gas flow direction of the plurality of fins, and also tends to adhere to the upper side of the region rather than the lower side.
On the other hand, as for the plurality of notch recesses provided in each fin, the end of the notch recess located on the upper side of the notch recess located on the lower side of each fin is the heating gas. Since it is located on the upstream side in the flow direction, the area near one end of each fin has a larger heat transfer area (heat receiving area) on the upper side than on the lower side, and tends to reach a high temperature. Therefore, even if the condensed water reaches the upper side of the region near one end of each fin from the upper wall portion of the can body, the temperature of this portion does not become extremely low. As a result, it is possible to suppress the generation of condensed water due to the temperature drop of the fins and appropriately prevent the heat exchanger from becoming an exhaust blockage.

The heat exchanger provided by the second aspect of the present invention is arranged in a can body in which the heating gas is supplied so as to be in a sideways posture and in which the heating gas travels sideways, and inside the can body. A heat transfer tube for recovering heat from the heating gas to heat hot water, a plurality of fins joined to the heat transfer tube, and heating of the peripheral wall portion of the can body more than the plurality of fins. A heat exchanger provided with a water cooling pipe wound around an outer surface portion on the upstream side in the gas flow direction for heating, and one end on the upstream side in the gas flow direction for heating of each fin has an upper side from the lower side. Is also characterized in that it is located on the upstream side in the heating gas flow direction.

According to such a configuration, the following effects can be obtained.
That is, since one end of each fin on the upstream side in the heating gas flow direction is located on the upper side of each fin on the upstream side in the heating gas flow direction rather than the lower side, the temperature of the region near one end is located. The distribution can be such that the upper side is hotter than the lower side. Therefore, even if the condensed water reaches the upper side of the region near one end of each fin from the inner surface of the upper wall portion of the can body, it is possible to prevent the temperature on the upper side from becoming extremely low. It becomes. As a result, similarly to the heat exchanger provided by the first aspect of the present invention, the generation of condensed water due to the temperature drop of the fins is suppressed, and the heat exchanger is appropriately prevented from becoming an exhaust blockage. It is possible.

In the present invention, preferably, it is a heat exchanger provided by the first aspect of the present invention, and one end of each fin on the upstream side in the heating gas flow direction has a heating gas on the upper side rather than a lower side. It is configured to be located on the upstream side in the flow direction.

Such a configuration corresponds to a configuration in which the configuration of the heat exchanger provided by the first aspect of the present invention and the configuration of the heat exchanger provided by the second aspect are combined, and heating of each fin. It is possible to more thoroughly prevent the temperature on the upper side of the region near one end on the upstream side in the gas flow direction from becoming lower due to the condensed water arriving from the inner surface of the upper wall of the can body. Become. Therefore, it is more preferable to surely prevent the exhaust blockage caused by the condensed water.

The water heating device provided by the third aspect of the present invention is characterized by comprising the heat exchanger provided by the first or second aspect of the present invention.
With such a configuration, the same effect as described for the heat exchanger provided by the first or second aspect of the present invention can be obtained.

In the present invention, preferably, an exhaust collecting cylinder provided on the downstream side in the heating gas flow direction of the heat exchanger and having an exhaust port for exhausting the heating gas that has passed through the heat exchanger to the outside. Further, the exhaust port is provided so as to face the upper region of the plurality of fins and not to face the lower region.

According to such a configuration, when the heating gas is supplied into the can body of the heat exchanger, the heating gas acts more on the upper region side than the lower region of each fin, and the upper portion. It is possible to raise the temperature on the side of the closer region. Therefore, it is more thoroughly prevented that the temperature of the upper region is lowered due to the condensate water reaching the upper region of each fin from the inner surface of the upper wall of the can body. As a result, it becomes more preferable in suppressing the temperature of each fin from becoming low and the generation of a large amount of condensed water.

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

It is a schematic cross-sectional view which shows an example of the water heating apparatus provided with the heat exchanger according to this invention. It is a cross-sectional view of a main part of FIG. It is an enlarged sectional view of the main part of FIG. It is sectional drawing of the main part which shows the other example of this invention.

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

The water heating device WH shown in FIG. 1 includes a fan 1, a burner 2, a heat exchanger HE, and an exhaust collecting cylinder 3 (exhaust case), and these are arranged and connected side by side.
This water heating device WH is in a so-called sideways posture. For example, the center line CL of the heat exchanger HE is substantially horizontal, but more accurately, the center line CL is inclined at an appropriate angle α with respect to the horizontal line HL. , The height of the exhaust collecting cylinder 3 side is set to be lower than that of the burner 2 side. This helps prevent the condensed water generated in the heat exchanger HE from flowing to the burner 2 side, as will be described later.

The burner 2 is, for example, a Bunsen burner, which is a so-called lateral combustion system. The burner 2 has a configuration in which a plurality of burner main bodies 20 (combustion pipes) arranged in the front-rear width direction (direction intersecting the paper surface of FIG. 1) of the water heating device WH are arranged in the burner case 21. Fuel gas is supplied from the nozzle 29a of the fuel gas supply head 29 and combustion air is supplied from the fan 1 to each burner main body 20, and a mixed gas thereof is introduced into each burner main body 20 to open sideways. The fuel gas burns at the burner portion 20a. The combustion gas (heating gas) generated by this combustion travels sideways due to the blowing pressure from the fan 1 and heads for the heat exchanger HE.
Reference numeral 90 in the drawing is a heat shield plate for preventing thermal damage to the burner case 21. Reference numeral 91 is a straightening vane, which has a plurality of ventilation holes 91a through which the combustion air supplied from the fan 1 passes, and the primary combustion air directly supplied to the burner main body 20 and the installation of the burner main body 20. It plays a role of defining the ratio with the secondary combustion air supplied to the region.

The heat exchanger HE includes a can body 4, a heat transfer tube 5 arranged in the can body 4, a plurality of fins 6, and a water cooling tube 7.
The can body 4 has, for example, a substantially rectangular cylindrical shape, is in a sideways posture as described above, and has an upper wall portion 40a, a lower wall portion 40b, and both side wall portions 40c as peripheral wall portions 40. ing.

The heat transfer tube 5 and the plurality of fins 6 are members for recovering heat from the combustion gas supplied from the burner 2 into the can body 4 to heat hot water. The heat transfer tube 5 has a configuration in which a plurality of straight tube body portions 50 are connected in a series via a bend tube 51 (see FIG. 2). In the present embodiment, a total of three rows of pipes in which a plurality of pipes 50 are arranged at intervals in the vertical height direction are provided in a substantially horizontal direction, but the present invention is limited to this. However, it is sufficient that at least one row of the pipe body portions is provided.
The plurality of fins 6 have a plate shape that stands up in the vertical height direction, and are arranged at intervals in the front-rear width direction of the water heating device WH. A plurality of tube body portions 50 of the heat transfer tube 5 penetrate the plurality of fins 6 and are joined by means such as brazing.

As is well shown in FIG. 3, one end of each fin 6 is located in a region S (one end 60 and a region in the vicinity thereof) on the upstream side of the combustion gas flow direction (heating gas flow direction in the present invention). A plurality of notch recesses 61 extending from the portion 60 toward the inter-regional region of the plurality of tubular portions 50 are provided. The plurality of notch recesses 61 are portions of the region S near one end of each fin 6 for avoiding an excessively high temperature between the regions of the plurality of tubular portions 50.
The end of the notch recess 61a (61) located on the uppermost side of the plurality of notch recesses 61 is located on the upstream side in the combustion gas flow direction by the dimension La from the end of the other notch recess 61.

Further, the one end portion 60 of each fin 6 is configured such that the upper side thereof is located on the upstream side in the combustion gas flow direction with respect to the lower side. More specifically, in the present embodiment, the one-end side region S is divided into a plurality of convex regions 62 by a plurality of notch recesses 61. Each convex region 62 is a region in a form protruding from each pipe body portion 50 located in the region S near one end to the upstream side in the combustion gas flow direction. Of these plurality of convex regions 62, for example, the protrusion dimension Lb from the tubular portion 50 of the upper two convex regions 62 (62a, 62b) is the protrusion dimension from the tubular portion 50 of the other convex region 62. Larger than Lc, the tips of the two convex regions 62a, 62b (part of one end 60) are larger than the tips of the other convex regions 62 (other parts of one end 60). It is located on the upstream side in the combustion gas flow direction by an appropriate dimension Ld.

The water cooling pipe 7 is wound around an outer surface portion of the peripheral wall portion 40 of the can body 4 on the upstream side in the combustion gas flow direction with respect to the plurality of fins 6 and the heat transfer pipe 5. Water such as tap water is supplied to the water cooling pipe 7, the peripheral wall portion 40 of the can body 4 is cooled, and the peripheral wall portion 40 is prevented from being heated to an abnormally high temperature by the combustion gas. The water that has passed through the water cooling pipe 7 is sent to the heat transfer pipe 5.

The exhaust collecting cylinder 3 is a member for exhausting the combustion gas that has passed through the heat exchanger HE to the outside as exhaust gas, and an exhaust port 31 is located near the upper portion of the terminal side wall portion 30 of the exhaust collecting cylinder 3. It is provided.
At least a part of the notch recess 61a and the two convex regions 62a and 62b are located in the projection region A of the exhaust port 31 in the direction of the combustion gas flow.

Next, the operation of the heat exchanger HE and the water heater WH equipped with the heat exchanger HE will be described.

First, the hot water supply by the hot water device WH is performed by heating the hot water flowing in the heat transfer tube 5 by driving and burning the burner 2 and recovering heat from the combustion gas by the heat transfer tube 5 and the plurality of fins 6. .. Here, since the peripheral wall portion 40 of the can body 4 of the heat exchanger HE is cooled by the water cooling pipe 7, condensed water is generated on the inner surface of the peripheral wall portion 40. Of this condensed water, the condensed water generated on the inner surface of the upper wall portion 40a of the can body 4 is blown off by the combustion gas or reaches the surface portion of each fin 6 along the inner surface of the upper wall portion 40a and adheres. To do. In this case, the condensed water adheres to a large amount of the condensed water in the region S near one end on the upstream side in the combustion gas flow direction of each fin 6, and also adheres in a large amount to the region S on the upper side of the region S near one end.

On the other hand, since the end of the notch recess 61a at the uppermost portion of each fin 6 is located upstream of the end of the other notch recess 61 in the combustion gas flow direction, it is located on the upper side of the region S near one end. Is more likely to get hotter than the lower side. Therefore, even if condensed water adheres to the upper side of the region S near one end of each fin 6, the temperature of the upper side of the region S near one end will be significantly lower than that of the lower side. Absent.

Further, as described above, the tip portions of the two upper convex regions 62a and 62b of each fin 6 project to the upstream side in the combustion gas flow direction with respect to the tip portions of the other convex regions 62. Therefore, the two convex regions 62a and 62b are more likely to be heated to a high temperature by the combustion gas than the other convex regions 62. Therefore, when condensed water adheres to the two convex regions 62a and 62b on the upper side of the region S near one end, it is more reliably avoided that the temperature drops significantly in these portions, and one end. The generation of condensed water in the near-part S region S is more thoroughly prevented.

Further, since the exhaust port 31 of the exhaust collecting cylinder 3 is provided so as to be biased toward the upper part of the terminal side wall portion 30, when the combustion gas passes through the can body 4, the upper portion side region in the can body 4 is provided. The flow velocity of the combustion gas in the above is higher than the flow velocity of the combustion gas in the lower region. Therefore, the temperature of the upper side of each fin 6 tends to be higher than that of the lower side. This also has the effect of eliminating the possibility that the upper side of the region S near one end of each fin 6 causes a significant temperature drop due to the condensed water arriving from the upper wall portion 40a.

If a large amount of condensed water is generated in the plurality of fins 6, a large amount of corrosion products are generated on the surface of the fins 6, and the plurality of fins 6 may be clogged to cause exhaust blockage. On the other hand, according to the present embodiment, it is possible to appropriately eliminate such a risk.

As described above, the water heating device WH is inclined so that the height of the exhaust collecting cylinder 3 side is lower than that of the burner 2 side, so that it occurs on the inner surface of the lower wall portion 40b of the can body 4. The condensed water flows on the inner surface of the lower wall portion 40b toward the fin 6 side. In this case, even if the condensate water comes into contact with the fin 6, clogging does not occur in a wide range of the fin 6 because it is a narrow portion at the lower end of the fin 6. Further, the condensed water generated on the inner surfaces of the side wall portions 40c reaches the lower wall portion 40b along the inner surface, but most of them evaporate on the way, so that the condensed water also covers a wide range of the fins 6. It does not cause clogging.

The present invention is not limited to the contents of the above-described embodiments. The specific configuration of each part of the heat exchanger and the water heating device according to the present invention can be variously redesigned within the scope intended by the present invention.

In the above-described embodiment, the exhaust collecting cylinder 3 side is inclined so as to have a lower height than the burner 2 side, but the present invention is not limited to this, and for example, contrary to the above, the burner 2 The exhaust collecting cylinder 3 side may be inclined so as to have a higher height than the side, or may be set in a state where there is no such inclination (the center line CL of the can body 4 is horizontal).

Further, in the above-described embodiment, of the plurality of notch recesses 61 of the fin 6, only the uppermost notch recess 61a is shorter than the other notch recess 61. The invention is not limited to this. For example, among the plurality of notch recesses 61, the lengths of the upper two notch recesses 61 may be shortened, and the lengths of the other notch recesses 61 other than these may be lengthened. Further, the lengths thereof may be gradually shortened from the lower notch recess 61 toward the upper notch recess 61.
In the heat exchanger provided by the first aspect of the present invention, the point is that, of the plurality of notch recesses provided in the fin, the notch recess (at least one notch) located on the upper side of the fin. The end of the recess) may be located upstream of the end of the other notch recess located on the lower side in the heating gas flow direction.

In the above-described embodiment, the tips of the upper two convex regions 62a and 62b of the plurality of convex regions 62 are arranged on the upstream side in the combustion gas flow direction with respect to the other convex regions 62. , The present invention is not limited to this. For example, the tip end portion of one convex region 62 located at the uppermost portion may be arranged on the upstream side in the combustion gas flow direction with respect to each tip portion of the other convex region 62. Further, the tips thereof may be located on the upstream side in the combustion gas flow direction from the lower convex region 62 toward the upper convex region 62.
In the heat exchanger provided by the second aspect of the present invention, the point is that one end of each fin on the upstream side in the heating gas flow direction is located on the upper side on the upstream side in the heating gas flow direction rather than the lower side. It suffices if it is configured to be. In the above-described embodiment, since the plurality of notched recesses 61 are provided, a plurality of convex regions 62 are formed on the side of the tube body portion 50 of the heat transfer tube 5, and such convex regions are formed. It is also possible to have a configuration in which 62 is not provided.
Although it is not very realistic, for example, it is possible to have a configuration as shown in FIG. 4 (the same parts as those in the above embodiment are designated by the same reference numerals as those in the above embodiment). Also in the configuration shown in FIG. 4, the upper end 60 of the fin 6 on the upstream side in the heating gas flow direction is located on the upstream side in the heating gas flow direction from the lower side, and the operation intended by the present invention. Is obtained.

The heating gas can be, for example, high-temperature exhaust gas discharged from the cogeneration system instead of the combustion gas. The specific shapes of the heat transfer tube and the plurality of fins are not limited to those described above.
The heat exchanger according to the present invention can also be used for applications other than those for hot water devices. The hot water device according to the present invention has a function of heating hot water to generate hot water, and is used as a general hot water supply device, for example, a bath hot water supply device, a hot water device for heating, a hot water device for melting snow, and the like. Can be configured.

HE heat exchanger WH hot water device S One end area (Fin heating gas flow direction one end area)
1 Fan 2 Burner 3 Exhaust assembly cylinder 31 Exhaust port 4 Can body 40 Peripheral wall (of the can body)
40a Upper wall (of the peripheral wall)
5 Heat transfer tube 50 Tube body 6 Fin 60 One end (one end on the upstream side of the fin in the gas flow direction for heating)
61 Notch recess 7 Water cooling pipe

Claims (5)

A can body that is in a sideways position and is supplied with heating gas so that it travels sideways inside.
A heat transfer tube arranged inside the can body and for recovering heat from the heating gas to heat hot water, and a plurality of fins joined to the heat transfer tube.
A water-cooled pipe wound around an outer surface portion of the peripheral wall portion of the can body on the upstream side in the heating gas flow direction with respect to the plurality of fins.
Is a heat exchanger equipped with
A plurality of tube bodies constituting the heat transfer tube penetrate through each of the fins in an arrangement arranged at intervals in the vertical height direction, and the fins are closer to one end on the upstream side in the heating gas flow direction. The region is provided with a plurality of notch recesses extending from the one end portion toward the inter-regional region of the plurality of tubular portions.
Of these plurality of notch recesses, the end of the notch recess located on the upper side of each fin is located on the upstream side in the heating gas flow direction with respect to the end of the other notch recesses located on the lower side. A heat exchanger characterized by being said to be. A can body that is in a sideways position and is supplied with heating gas so that it travels sideways inside.
A heat transfer tube arranged inside the can body and for recovering heat from the heating gas to heat hot water, and a plurality of fins joined to the heat transfer tube.
A water-cooled pipe wound around an outer surface portion of the peripheral wall portion of the can body on the upstream side in the heating gas flow direction with respect to the plurality of fins.
Is a heat exchanger equipped with
A heat exchanger characterized in that one end of each fin on the upstream side in the heating gas flow direction is configured such that the upper side is located on the upstream side in the heating gas flow direction with respect to the lower side. The heat exchanger according to claim 1.
A heat exchanger characterized in that one end of each fin on the upstream side in the heating gas flow direction is configured such that the upper side is located on the upstream side in the heating gas flow direction with respect to the lower side. A water heating device comprising the heat exchanger according to any one of claims 1 to 3. The water heating device according to claim 4.
Further, an exhaust collecting cylinder provided on the downstream side in the heating gas flow direction of the heat exchanger and having an exhaust port for exhausting the heating gas that has passed through the heat exchanger to the outside is further provided.
A water heating device in which the exhaust port faces the upper region of the plurality of fins and does not face the lower region.

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