JPH07167586A - Heat exchanger - Google Patents

Abstract

PURPOSE:To make compact the whole structure of a heat exchanger device by forming fins of a heat exchanger unit with a high thermal conductivity material, such as copper and constituting water flow tubes or fins in a sub-heat exchanger unit with highly corrosion resistant materials, such as aluminum alloy. CONSTITUTION:Water flow tubes 11 in a main heat exchanger unit 1a are constructed with three stages where each stage is meanderingly laid out laterally in two or three rows. The water flow tubes 11 and fins 12a into which the water flow tubes are penetrated are formed with copper which is a high conductivity material. The water flow tubes 11 in the other sub-heat exchanger unit 1b are meanderingly laid out laterally in three rows under one stage structure. The water flow tubes 11 and the fins 12b into which the tubes are penetrated are formed with aluminum alloy which is excellent in corrosion resistance. The adoption of the fins 12 of a highly thermal conductivity material makes it possible to reduce the size of the main heat exchanger unit 1a, and compact the whole structure of the heat exchanger device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanging device, and more particularly to a heat exchanging device for condensing water vapor in combustion exhaust gas and absorbing the latent heat in the heat exchanging portion to improve heat exchanging efficiency. It is about.

[0002]

2. Description of the Related Art As a heat exchanger of the above type, as shown in FIG. 3, a gas burner (3) and a heat exchanger (1) are provided.
There is a combination of and. This heat exchanger (1)
Main heat exchange part (1a) which mainly absorbs sensible heat of combustion exhaust gas of the gas burner (3), and sub heat exchange part (1b) which is arranged below it and mainly absorbs latent heat of combustion exhaust gas of the gas burner (3).
The main heat exchange part (1a) on one side is a water pipe.
(11) and a large number of fins (12a) and (12a) provided on the outer periphery thereof, and the other sub heat exchange section (1b) is upstream of the main heat exchange section (1a) in the water pipe (11). It is composed of a side portion and a large number of fins (12b) (12b) provided on the outer periphery thereof. And
The water pipe (11) and fins (12a) (12b) constituting the main heat exchange part (1a) and the sub heat exchange part (1b) are formed of an aluminum alloy in consideration of the corrosion problem described later. There is.

In the gas burner (3), the flame hole portion is set downward, and the main heat exchange portion (1) is provided in the vicinity of the flame forming region.
It is arranged so that a) is located. In this case, when the gas burner (3) is combusted and tap water is supplied from the water pipe (11) located on the side of the sub heat exchange section (1b), the water in the water pipe (11) flows through the gas burner (3). ) Heat is absorbed from the water pipe (11) and fins (12a) and (12b) to become hot water, and the main heat exchange part (1a)
Of the gas burner (3), the sensible heat of the combustion exhaust gas of the gas burner (3) is absorbed mainly by the main heat exchange section (1a). Department
In (1b), the action of mainly condensing the steam in the combustion exhaust gas of the gas burner (3) and absorbing the latent heat thereof is performed.
That is, in the sub heat exchange section (1b), the flue gas deprived of the sensible heat in the main heat exchange section (1a) to cool the combustion exhaust gas, the water pipe (11) in the sub heat exchange section (1b) below the dew point temperature. The drain is generated by contacting the fins (12b) (12b) with each other, and the latent heat at that time is absorbed by the water passing through the water pipe (11) to improve the thermal efficiency.

On the other hand, the drain adheres to the sub heat exchange section (1b) as described above, and the corrosive component (nitrogen oxide etc.) in the combustion exhaust gas is melted to the drain. Sub heat exchange section
Since (1b) is formed of an aluminum alloy having excellent corrosion resistance, the sub heat exchange section (1b) is resistant to corrosion. However, this has a problem that the entire device becomes large.

In this case, the auxiliary heat exchange part (1b) in which the drainage which causes the corrosion is remarkable and the main heat exchange part (1a) in which the drainage is hardly generated are uniformly excellent in corrosion resistance. It is made of aluminum alloy. However, aluminum alloy has a relatively low thermal conductivity (about 0.52 cal /
℃ cm · sec), to obtain the specified thermal efficiency, water pipe
The surface area of (11) and fins (12a) (12b) must be increased. Therefore, the surface area of the water passage pipe (11) and the fins (12a) (12a) located in the main heat exchange part (1a) where the above-mentioned drain is hardly generated also has to be increased, and the entire device becomes large. .

According to the present invention, the main heat exchange section (1a) is constructed by providing a large number of fins (12a) (12a) on the outer periphery of the water pipe (11) as described above. A large number of fins (12b) (12b) are provided on the outer periphery of the upstream side of the main heat exchange section (1a) to form the auxiliary heat exchange section (1b), and the main heat exchange is performed downstream of the combustion device in the exhaust passage. By arranging the section (1a) and the sub heat exchange section (1b) in this order, the sensible heat of the combustion exhaust is absorbed by the former main heat exchange section (1a), and the latter sub heat exchange section (1b). In order to make the entire heat exchange device compact, it is possible to make the heat exchange device in contact with the water passage pipe (11) or the fins (12b) (12b) by absorbing the sensible heat and latent heat from the combustion exhaust gas. The task is to

[0007]

[Technical Means] The technical means of the present invention taken to solve the above-mentioned problem is "fins (12a) (12a) of the main heat exchange part (1a)".
Is made of a material with high thermal conductivity such as copper, and the water pipes (11) and fins (12b) (12b) in the sub heat exchange section (1b) are made of a material with high corrosion resistance such as an aluminum alloy. Is.

[0008]

The above technical means of the present invention operates as follows. Since the fins (12a) and (12a) in the main heat exchange part (1a) are made of a material having a high thermal conductivity such as copper, the surface area is small while ensuring the same thermal efficiency as the conventional one. Therefore, the main heat exchange section (1a) can be downsized. In the above, in selecting the material of the fins (12a) (12a) in the main heat exchange part (1a), the corrosion resistance is not taken into consideration, but the main heat exchange part (1a) is exclusively used. Since the drain is hardly generated only by absorbing sensible heat, the fin (1
There is no concern about corrosion of 2a) and (12a). In addition, as described in the above-mentioned conventional example, the drainage in which the corrosive component is melted causes the sub heat exchange part (1
Although it occurs in b), the water passage pipe (11) and the fins (12b) (12b) of the sub heat exchange part (1b) are made of a material having a good corrosion resistance such as an aluminum alloy like the conventional one. Since it is formed, it is possible to cope with the corrosion of the sub heat exchange portion (1b).

[0009]

[Effect] The present invention having the above-mentioned structure has the following unique effects. Since the main heat exchange section (1a) can be downsized by adopting the fins (12a) (12a) made of a material having a high heat conductivity, the heat exchange apparatus as a whole can be made compact accordingly.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. The embodiment shown in FIG. 1 is one in which the present invention is applied to a water heater. This one has a heat exchanger (1) at the bottom of the water heater body.
An air supply box provided with a can body (6) for accommodating a gas, a gas burner (3) being provided on an upper part of the can body (6), and an air supply chamber (42) being provided on an upper part.
(7) is provided, a fan (4) is provided in the upper part of the air supply box (7), and an exhaust passage (21) is provided downstream of the combustion exhaust flow of the heat exchanger (1). Is provided so as to run up and down the water heater main body.

The heat exchanger (1) is mainly a gas burner.
From the main heat exchange part (1a) that absorbs the sensible heat of the combustion exhaust of (3), and the sub heat exchange part (1b) that is arranged below it and that mainly absorbs the latent heat of the combustion exhaust of the gas burner (3). It is configured. One main heat exchange part (1a) consists of a water pipe (11) equipped with annular fins (12a) (12a), and the other sub heat exchange part (1b)
Consists of a water pipe (11) located upstream of the main heat exchange part (1a) in the water passage and equipped with annular fins (12b) (12b). The lower end of the can body (6) is open, and the drain generated in the auxiliary heat exchange section (1b) is discharged to the outside from the drain discharge port (8) below the can body (6). .

A water pipe (11) in the main heat exchange section (1a)
Is composed of three stages, and each stage is arranged in two rows or three rows in a meandering shape, and the water pipe (11) of the main heat exchange section (1a) is
The fins (12a) (12a) penetrating therethrough are formed of copper having a high thermal conductivity (the thermal conductivity of copper is about 0.93 cal / ° C cm · sec). The water pipe (11) of the other sub heat exchange section (1b) has a one-stage structure in which the sub heat exchange section (1) is arranged in three rows in a meandering manner.
The water pipe (11) and the fins (12b) (12b)
b) is made of an aluminum alloy with good corrosion resistance. Further, the main heat exchange part (1a) of the heat exchanger (1) is made compact as compared with the above-mentioned conventional one. That is, the heat absorption area of the water pipe (11) and the fins (12a) (12a) in the main heat exchange part (1a) ensures the same thermal efficiency as the above-mentioned conventional one from the relationship of the thermal conductivity of the constituent materials. However, it is set smaller than the conventional one.

The gas burner (3) is of the all primary air combustion type and comprises a perforated plate (31) and a mixing chamber (32) above the porous plate (31). The mixing chamber (32) has a gas nozzle (33). )
Is facing. The exhaust passage (21) is the can body of the water heater.
It is pulled out from the lower end opening of (6), and the exhaust port (2) at its downstream end opens to the upper part of the water heater.

Therefore, the fan (4) is operated to supply the primary air to the mixing chamber (32), and the gas is supplied from the gas nozzle (33) to burn the gas burner (3), so that the water passage (1
When tap water is supplied to (1), the combustion exhaust gas generated in the gas burner (3) is discharged from the main heat exchange section (1a) of the heat exchanger (1) → the sub heat exchange section ( It flows from 1b) to the exhaust passage (21) and is discharged to the outside from the exhaust port (2). On the other hand, the main heat exchange section
(1a) and the water in the water pipe (11) of the sub heat exchange part (1b), the generated heat of the gas burner (3) is the same as the above fins (12a) (12b) and water pipe (1).
It is absorbed from 1) and made hot water from the upper water pipe (11) and taken out to the outside. Among the endothermic action at this time, the action of absorbing the sensible heat of the combustion exhaust of the gas burner (3) is mainly performed in the main heat exchange section (1a), and in the sub heat exchange section (1b), Mainly, the combustion exhaust gas of the gas burner (3) is condensed and the latent heat is absorbed. That is, in the sub heat exchange section (1b), mainly the sensible heat is taken away and the cooled combustion exhaust gas is placed in the water pipe (1b) located in the sub heat exchange section (1b) below the dew point temperature.
Drain is generated by bringing it into contact with 1) or the fins (12b) (12b), and the latent heat at that time is absorbed by the water flow in the water flow pipe (11). At this time, drain is generated in the sub heat exchange section (1b), but since the sub heat exchange section (1b) is formed of an aluminum alloy having high corrosion resistance, the sub heat exchange section (1b) is corroded. There is nothing to do. The main heat exchange section (1a)
Is formed of copper with good thermal conductivity in order to form a compact structure, and therefore the corrosion resistance is poor, but the main heat exchange part (1
No drainage occurs in a), so there is no problem of corrosion.

The above embodiment can be modified as follows. ． Although the sub heat exchange part (1b) is made of an aluminum alloy in the above embodiment, it may be made of stainless steel. In addition, the water pipe (11) and the fins (1) in the main heat exchange section (1a)
Although 2a) and (12a) are formed of copper, the water pipe (11) may be formed of an aluminum alloy or the like and the fins (12a) and (12a) may be formed of copper.

In any of the above cases, a copper alloy may be used instead of copper. ． In the above embodiment, the water pipe (11) is bent in a meandering manner to form a four-stage structure, in which the lowermost stage is the auxiliary heat exchange section (1b) and the other three stages are the main heat exchange section. Although (1a) is used, depending on the sensible heat absorbing capacity of the main heat exchange section (1a), the sub heat exchange section (1b) that absorbs latent heat has a plurality of stages such as two stages and three stages from the bottom. In this case, the water pipe (11) at each stage in the sub heat exchange section (1b)
Also, the fins (12b) (12b) are formed of an aluminum alloy or the like.

As described above, when the sub heat exchange section (1b) is formed in a plurality of stages, water may be supplied from the water pipes (11) at the second or third stage from the bottom. Also, including the case of the above embodiment, the hot water may be taken out from the second or third stage from the top. In addition, as shown in FIG. 2, a large number of fins (12b) (12b) are provided between the can body (6) and the exhaust passage (21) so as to communicate with the most upstream end of the water pipe (11). Tap water may be supplied to the auxiliary water pipe (11a) by interposing the auxiliary water pipe (11a) having a flat rectangular cross section.
Then, the auxiliary water flow pipe (11a) and the fins (12b) and (12b) are used as a sub heat exchange section (1b), and the other are used as a main heat exchange section (1a). In such a case, the auxiliary water pipe (11a) and fins (12b)
(12b) is formed of an aluminum alloy or the like. ． In the above embodiment, the fan (4) is provided on the air supply passage side, but it may be provided on the exhaust passage (21) side. ． Although the present invention is applied to the water heater in the above-described embodiments, the present invention can be applied to a heat exchange device such as a heater that circulates heated water in addition to the water heater. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of another embodiment.

FIG. 3 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 (11) ・ ・ ・ Water pipe (1a) ・ ・ ・ Main heat exchange part (1b) ・ ・ ・ Sub heat exchange part (12a), (12b) ・ ・ ・ Fin

Claims (2)

[Claims] 1. A large number of fins (12a) on the outer circumference of the water pipe (11).
(12a) is provided to form the main heat exchange section (1a), and the water pipe (1
A large number of fins (12b) (12b) are provided on the outer circumference of the upstream side of the main heat exchange section (1a) in 1) to form the sub heat exchange section (1b), and the exhaust passage is provided on the downstream side of the combustion device. Main heat exchange part (1
By arranging a) and the sub heat exchange part (1b) in this order in sequence, the sensible heat of the combustion exhaust is absorbed by the former main heat exchange part (1a) and burned by the latter sub heat exchange part (1b). Exhaust pipes (11) and fins (1
2b) In the heat exchange device in contact with (12b) so as to absorb sensible heat and latent heat from the combustion exhaust gas, the main heat exchange section (1a)
The fins (12a) and (12a) are made of a material with high thermal conductivity such as copper, and the water pipes (11) and fins (12b) and (12b) in the sub heat exchange section (1b) are made of aluminum alloy or other corrosion resistant material. Heat exchanger composed of rich materials. 2. The heat exchange device according to claim 1, wherein the water passage pipe (11) in the main heat exchange portion (1a) is made of a material having a high thermal conductivity such as copper.