JPH09126554A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure miniaturization of an apparatus without deteriorating heat exchange efficiency by providing a plurality of branch flow passages branched at an inlet side of a heat exchanger to a heated water circuit heat exchanger, and joinning the branch flow passages at an outlet from the heat exchanger or on the downstream side of the outlet. SOLUTION: Water to be heated flowing frown a supply pipe 16 into second and third water passage pipes 12, 13 of a sub-heat exchanger 1b absorbs latent heat and is raised in its temperature, which water to be heated passing through a second water passage pipe 12 flows into a main heat exchanger 1a and absorbs sensible heat and is hence raised in its temperature into high temperature hot water. Low temperature hot water passing through a third water passage pipe 13 is mixed with high temperature hot water flowing out from the main heat exchanger 1a to provide predetermined hot water. Hereby, an interval between the one branch flow passage and the other branch flow passage is more reduced than the radius of curvature of a bent pipe part 102. Accordingly, the entire of the heat exchanger is miniaturized compared with the prior art.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchange device, and more particularly to a heat exchange device equipped with a stainless steel heat exchanger.

[0002]

2. Description of the Related Art As the heat exchange device, there has already been proposed a condensing type device which condenses water vapor in the combustion exhaust gas from the burner and absorbs the latent heat thereof. In this case, as shown in FIG. 3 and FIG.
(2) The main heat exchanger (1a) and the sub heat exchanger (1b) are arranged in this order from the upstream side in the combustion exhaust path below the gas burner (3) in the inside.

One auxiliary heat exchanger (1b) is made of stainless steel, and a plurality of substantially parallel straight pipe parts (101) (101) are connected at their ends by bending pipe parts (102) (102). As a result, the heated water circuit is formed in a meandering shape. The other main heat exchanger (1a) is made of copper having high thermal conductivity, and has a heated water circuit having the same configuration as the sub heat exchanger (1b).
The outlet side of the heated water circuit of the sub heat exchanger (1b) is connected to the inlet side of the heated water circuit of the main heat exchanger (1a).

In this case, the gas burner is driven by the air discharged from the fan (4) connected to the upper end of the can body (2).
When (3) is burned and water is supplied to the main heat exchanger (1a) and the sub heat exchanger (1b), the sensible heat of combustion exhaust gas from the gas burner (3) in the main heat exchanger (1a) Is absorbed. Then, in the auxiliary heat exchanger (1b), the combustion exhaust gas is cooled to a temperature below the dew point to generate drainage, and latent heat corresponding to that is applied to the straight pipe parts (101) (101) of the auxiliary heat exchanger (1b). Is absorbed. In this heat exchange device, since the latent heat is absorbed in addition to the sensible heat,
The heat exchange efficiency is high.

Further, although a large amount of the drain adhered to the sub heat exchanger (1b) contains a corrosive component (nitrogen oxide, etc.) in combustion exhaust gas, the sub heat exchanger (1b) Since it is made of stainless steel with good corrosion resistance, this sub heat exchanger
Corrosion of (1b) is prevented.

[0006]

However, according to this technique, when the bending tube portions (102) and (102) are manufactured by bending, since the bending tube portions are made of stainless steel,
(102) The radius of curvature of (102) cannot be reduced. Therefore, the distance between the straight pipe portions (101) and (101) connected by the bent pipe portions (102) and (102) becomes large. Moreover,
Since these straight pipe parts (101) (101) and bent pipe parts (102) (102) are configured in one flow path, the arrangement of the straight pipe parts (101) (101) is likely to be restricted. . Therefore, the sub heat exchanger (1b) cannot be downsized.

On the other hand, it is conceivable to reduce the number of the straight pipe portions (101) (101) to realize the miniaturization, but in this case, the heat exchange efficiency in the sub heat exchanger (1b) Is reduced.
Therefore, this product has a problem that the sub heat exchanger (1b) cannot be downsized without lowering the heat exchange efficiency of the sub heat exchanger (1b). The invention of claim 1 is
`` A plurality of straight pipe parts (101) (101) are bent at their ends and bent pipe parts (102)
In a heat exchange device in which a heat exchanger (10) equipped with a heated water circuit made of stainless steel formed in a meandering shape by inserting the heat exchange device is inserted into the combustion exhaust passage, the heat exchange device The task is to enable downsizing without lowering.

[0008]

[Means for Solving the Problems] According to the means for solving the problems of the first aspect of the present invention, "a plurality of heated water circuits of the heat exchanger (10) are branched at the inlet side to the heat exchanger (10) And the branch passages are merged at the outlet from the heat exchanger (10) or at the downstream side thereof ”.

In this case, since the heated water circuit of the heat exchanger (10) is composed of a plurality of branch flow paths branched at the inlet side to the heat exchanger (10), one branch The straight pipe portion (101) of the flow passage and the straight pipe portion (101) of the other branch flow passage are not connected by the bent pipe portion (102). Therefore,
The distance between both of these straight pipe parts is such that the bending pipe part (102)
Is not limited by the size (radius of curvature) of the above, and can be smaller than this.

Here, as in the second aspect of the invention, "a main heat exchanger (1a) arranged upstream of the combustion exhaust gas is provided separately from the heat exchanger (10), and the heat exchange is performed. The outlet side of the heated water circuit of the vessel (10) was connected to the inlet side to the main heat exchanger (1a) '', in the same manner as the conventional one described above, the main heat exchanger (1a) The sensible heat of the combustion exhaust gas from the gas burner (3) is absorbed at, the latent heat is absorbed at the heat exchanger (10), and drain is generated in the heat exchanger (10). That is, the heat exchanger (10) functions as the sub heat exchanger (1b) of the heat exchange device of the condensing type described above. The sub heat exchanger (1b) has the same function as that of the first aspect of the invention.

Further, in the invention of claim 2, as in the invention of claim 3, "the outlet side of a part of the branch flow passages constituting the heated water circuit of the heat exchanger (10) is the main Heat exchanger
(1a) is connected to the inlet side, the outlet side of the other branch flow path constituting the heated water circuit is joined to the outlet side from the main heat exchanger (1a) '' The water to be heated that has passed through a part of the branch flow paths constituting the heated water circuit of the exchanger (10) flows into the main heat exchanger (1a) and is further heated. Then, at the outlet side of this main heat exchanger (1a), it joins with the water to be heated that has passed through another branch flow path that constitutes the above-mentioned water to be heated circuit.

In this case, the flow rate of the water to be heated distributed to the main heat exchanger (1a) becomes small, and the combustion exhaust gas is hard to be cooled by the main heat exchanger (1a) accordingly. This makes it difficult for drain to occur in the main heat exchanger (1a). Further, the water to be heated passing through the main heat exchanger (1a) is heated to a high temperature because the flow rate to the main heat exchanger (1a) decreases. Then, in this high-temperature water, the heat exchanger (10)
The low temperature water to be heated from is mixed. Therefore, hot water having the same temperature as that obtained by connecting all the branch flow paths of the heated water circuit of the heat exchanger (10) to the main heat exchanger (1a) can be obtained.

Here, in the above-mentioned inventions of claims 1 to 3, as in the invention of claim 4, "the heat exchanger (10) is
The straight pipe parts (101) and (101) may pass through a stainless steel fin group ”. In this case, the heat of the combustion exhaust gas is also absorbed by the fin group,
The water to be heated in the straight pipe portions (101) (101) is efficiently heated.

Further, in the invention of claim 2 or 3, as in the invention of claim 5, "the main heat exchanger (1a) may be made of copper or stainless steel".

[0015]

As described above, according to the first aspect of the present invention, the straight pipe portions of one branch flow passage and another branch flow passage forming the heated water circuit of the heat exchanger (10) are mutually connected. The interval can be made smaller than the radius of curvature of the bent tube portion (102), and the branch flow passages can be packed and arranged. Therefore, the entire heat exchanger (10) can be downsized as compared with the conventional one in which the same number of the straight pipe portions (101), (101) are configured in one flow path.
Further, the heat exchange efficiency does not decrease by setting the number of the straight pipe portions (101) (101) to be the same as that of the conventional one. Therefore, the heat exchange device can be downsized without lowering the heat exchange efficiency.

According to the second aspect of the present invention, the latent heat is absorbed in addition to the sensible heat of the combustion exhaust gas, so that the heat exchange efficiency of the heat exchange device is improved. Further, the sub heat exchanger (1b) as the heat exchanger (10) can be downsized, and the entire condensing type heat exchange device can be downsized. Generally, the secondary heat exchanger
(1b) is the main heat exchanger (1
Since it is configured to be larger than a), the effect of reducing the size of the heat exchange device by reducing the size of the sub heat exchanger (1b) becomes particularly large.

In the invention of claim 3, the main heat exchanger (1a)
Therefore, the main heat exchanger (1a) is prevented from being corroded. In particular, when the main heat exchanger (1a) is made of copper having high thermal conductivity, corrosion of the main heat exchanger (1a) is prevented, and heat in the main heat exchanger (1a) is prevented. The exchange efficiency is high. Moreover, even if the ratio of the main heat exchanger (1a) in both heat exchangers is increased, this main heat exchanger
Since it is possible to prevent the occurrence of drain in (1a), even if the size of the heat exchanger (10) made of stainless steel having a small thermal conductivity is made smaller than the volume increase of the main heat exchanger (1a). The same heat exchange efficiency can be obtained. Therefore, also in this respect, the heat exchange device can be downsized.

In the invention of claim 4, the water to be heated in the straight pipe portions (101) (101) is also heated by the heat absorbed by the fin group, so that the heat in the heat exchanger (10) is The exchange efficiency is improved, and the heat exchange efficiency of the entire heat exchange device is further improved.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. As shown in FIG. 1, this embodiment is applied to a water heater. This water heater has a fan (4) connected to the upper end of the can body (2),
A gas burner (3), a main heat exchanger (1a), and a sub heat exchanger (1b) are arranged in this order in the order (2) in the downward direction. An exhaust pipe (21) is connected to the lower end of the body of the can body (2), and a drain discharge pipe (22) is connected to the center of the bottom wall. The gas burner (3) has a gas valve (51).
Gas is supplied from a gas circuit (5) equipped with.

First water pipe constituting the main heat exchanger (1a)
(11) and a large number of fins (14) (14) around it are made of copper, and the first water pipe (11) is, as shown in FIGS. 1 and 2,
It is composed of a pair of parallel first straight pipe portions (111) (111) and a U-shaped first bent pipe portion (112) connecting one ends of the first straight pipe portions (111) (111). The first straight pipe portions (111) (111) are installed in a substantially horizontal posture between the side wall portions of the body of the can body (2).
The fins (14) and (14) are arranged in a row over the straight pipe portions (111) and (111). Also, the first bent tube portion (112) is the can body.
It is exposed on the outside of the body of (2).

Further, the water pipe constituting the sub heat exchanger (1b) and a large number of fins (15) (15) around the water pipe are made of stainless steel, and the water pipe of the sub heat exchanger (1b) is , A pair of second and third water pipes (12) and (13) branched at the upstream end.
One of the third water pipes (13) is the same as the main heat exchanger (1a).
It is composed of a pair of third straight pipe parts (131) (131) and a third bent pipe part (132), and the other second water pipe (12) has a large number of parallel second straight pipe parts (121). The (121) is a U-shaped second bent tube portion (122) (122)
It is formed in a meandering shape by being connected by. Further, the second straight pipe portions (121) (121) are arranged side by side so as to surround the third straight pipe portions (131) (131) as shown in FIG.

The second straight pipe parts (121) (121) and the third straight pipe part
(131) (131) is erected between the body part side walls of the can body (2) like the first straight pipe parts (111) and (111).
The fins (15) and (15) are continuously provided so as to straddle the (121) and (121) and the third straight pipe portions (131) and (131). In addition, the second bent tube portion (122) (122) and the third bent tube portion (132) are the can body.
It is exposed to the outside of (2).

Further, as shown in FIGS. 1 and 2, the downstream end of the second water pipe (12) is connected to the upstream end of the first water pipe (11) and the third water pipe (13). The downstream end of is connected to the downstream end of the first water pipe (11). In addition, the second
A supply pipe (16) for supplying heated water to the sub heat exchanger (1b) is connected to a branch point on the upstream side of the third water pipes (12) and (13).

In this case, when the gas valve (51) is opened and the gas burner (3) is ignited while the fan (4) is operating, the gas burner (3) is in a combustion state and its combustion exhaust gas is exhausted. Is sent downward. Then, this combustion exhaust heats the main heat exchanger (1a), and the sensible heat thereof is absorbed by the main heat exchanger (1a). Then, the temperature of the combustion exhaust gas is lowered below the dew point in the sub heat exchanger (1b), whereby the second and third water pipes (12) (13) and the fins of the sub heat exchanger (1b) are cooled. (15) Drain is generated in (15), and the latent heat corresponding to that is absorbed by the sub heat exchanger (1b). The drain attached to the sub heat exchanger (1b) is dropped and discharged to the outside through the drain discharge pipe (22).

In this combustion state, the heated water flowing from the supply pipe (16) into the second and third water passage pipes (12) and (13) of the sub heat exchanger (1b) first absorbs the latent heat. The heated water that has been heated up and passed through one of the second water pipes (12) flows into the main heat exchanger (1a), absorbs the sensible heat, and is further heated up to a high temperature. Becomes Then, the low-temperature hot water that has passed through the third water pipe (13) is mixed with the high-temperature hot water that has flowed out of the main heat exchanger (1a), and hot water of a predetermined temperature is obtained. This hot water is supplied to the bath or the like by the hot water supply pipe (17). In this structure, the third water pipe (13) functions as a bypass circuit for the main heat exchanger (1a).

Further, since the flow rate of the main heat exchanger (1a) becomes smaller than the flow rate of the water to be heated in the sub heat exchanger (1b), the main heat exchanger (1a) is correspondingly reduced in flow rate. As a result, the combustion exhaust gas is less likely to be cooled, and drainage is less likely to occur in the main heat exchanger (1a). Therefore, the main heat exchanger made of copper with poor corrosion resistance (1a)
Is less likely to be corroded. Water pipes constituting the sub heat exchanger (1b) are the second water pipe (12) and the third water pipe.
Since it is composed of (13), the distance between these straight pipe portions is not restricted by the size (radius of curvature) of the second bent pipe portion (122), and can be made smaller than this. it can. Thereby, as described above, the second straight pipe portion (12
1) (121) can be arranged in a mode surrounded by the third straight pipe portions (131) (131). Therefore, the height of the sub heat exchanger (1b) is low without reducing the total number of the straight pipe portions. Further, the fins (15) (15) are made of stainless steel,
Due to its low thermal conductivity, the heat exchange efficiency does not decrease even if these fins (15) (15) are made small. Also in this regard,
The sub heat exchanger (1b) can be downsized.

In this embodiment, the sub heat exchanger (1b)
Is the heat exchanger (10) according to claim 1. Further, the second and third straight pipe portions (121) (131) are the straight pipe portion (101) according to claim 1, and the second and third bent pipe portions (122) (132).
Is the bent tube portion (102) according to claim 1. Furthermore,
The second and third water pipes (12) and (13) are the branch flow passages described in claim 1.

The sub heat exchanger (1b) may be constructed such that the straight pipe portion and the bent pipe portion which are separately formed are integrally assembled. In this case, after attaching both ends of the straight pipe portion to the side wall of the body of the can body (2), the bent pipe portion is opened from both end openings of the straight pipe portion exposed to the outside of the can body (2). A method of inserting both ends and brazing both of them over the entire circumference can be adopted. By this method, the sub heat exchanger (1b) can be easily assembled. Further, since only the bending tube portion needs to be bent, this processing is easy.

Further, in this embodiment, by adjusting the distribution of the heated water flowing into the main heat exchanger (1a) based on the temperature of the combustion exhaust gas, the main heat exchanger (1a) It is also possible to adopt a configuration in which the occurrence of drain is constantly prevented.
In this case, for example, an exhaust temperature sensor is provided directly below the main heat exchanger (1a), and the flow rate is adjusted to adjust the flow rate distribution to the upstream branch points of the second and third water pipes (12) and (13). Equipment
A configuration in which a control device that outputs a control signal to the flow rate control device based on the temperature detected by the exhaust temperature sensor can be adopted.

Further, in this embodiment, the condensing type is used, but the present invention is not limited to this as long as the heat exchanger is made of stainless steel. or,
The above-mentioned bypass circuit is not provided, that is, both the downstream ends of the second and third water pipes (12) and (13) of the auxiliary heat exchanger (1b) are connected to the first heat exchanger of the main heat exchanger (1a). It may be connected to the upstream end of the water pipe (11).

[Brief description of the drawings]

FIG. 1 is a sectional view of a heat exchange device according to an embodiment of the present invention.

FIG. 2 is a side view of the main heat exchanger (1a) and the sub heat exchanger (1b) of the heat exchange device.

FIG. 3 is a cross-sectional view of a conventional heat exchange device.

FIG. 4 is a side view of a main heat exchanger (1a) and a sub heat exchanger (1b) of a conventional heat exchange device.

[Explanation of symbols]

 (3) ・ ・ ・ Gas burner (10) ・ ・ ・ Heat exchanger (101) ・ ・ ・ Straight pipe part (102) ・ ・ ・ Bent pipe part

Claims (5)

[Claims] 1. A heat exchange comprising a stainless steel heated water circuit formed in a meandering shape by connecting a plurality of straight pipe parts (101) (101) at their ends by a bent pipe part (102). vessel
In the heat exchange device having (10) inserted in the combustion exhaust path, the heated water circuit of the heat exchanger (10) is a plurality of branch flow paths branched at the inlet side to the heat exchanger (10). At the same time, a heat exchange device in which the branch passages are merged at the outlet from the heat exchanger (10) or at the downstream side thereof. 2. A main heat exchanger (1a) arranged on the upstream side of the combustion exhaust gas is provided separately from the heat exchanger (10), and an outlet of a heated water circuit of the heat exchanger (10). Side to the main heat exchanger (1
The heat exchange device according to claim 1, which is connected to an inlet side to a). 3. The water to be heated of the heat exchanger (10) is connected to an outlet side of a part of a branch flow path constituting a heated water circuit to an inlet side of the main heat exchanger (1a). The heat exchange device according to claim 2, wherein the outlet side of another branch flow path constituting the circuit is joined to the outlet side of the main heat exchanger (1a). 4. The heat exchange device according to claim 1, wherein the heat exchanger (10) has a configuration in which the straight pipe portions (101) (101) penetrate a stainless fin group. . 5. The heat exchange device according to claim 2, wherein the main heat exchanger (1a) is made of copper or stainless steel.