JP2000146304A - Heat exchanger for recovering waste heat of hot-water supplier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent corrosion due to drain by a method wherein a multitude of finned tubes, having a multitude of fins prepared by machining the outer peripheral surface of an aluminum material having a through hole, are installed in parallel between the side plates of stainless steel and water passing tubes of copper are penetrated through the through holes of the finned tubes, while the terminal ends of the water passing tubes projected from the openings of the side plates are connected by U-tubes. SOLUTION: A plurality of finned tubes 20, made of aluminum and provided with a multitude of fins 21 on the outer peripheral surface of a through hole formed along the axial center of an aluminum material by machining, are formed so as to have a predetermined total length and are arranged between side plates 30 made of stainless steel, while a water passing tube 23 made of copper is penetrated through respective through holes of the finned tubes. The terminal end units 23a of the water passing tubes 23 are projected from openings 31 bored on the side plates 30, and are connected by U-tubes 25 made of copper to connect neighboring terminal units 23a and form a hot-water supplying passage, through which hot-water conducted to flow through the water passing tubes 23 flows whereby a heat exchanger for recovering waste heat is constituted. According to this method, anti-corrosive materials such as aluminum and stainless steel are employed for parts, contacted with combustion exhaust gas and absorb the waste heat of the same, whereby corrosion due to drain can be prevented and the durability of the exchanger can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for recovering waste heat of a water heater which is incorporated in an exhaust passage of a forced-fired water heater to recover waste heat contained in combustion exhaust gas.

[0002]

2. Description of the Related Art As a gas burning appliance such as a water heater, a forced burning type in which combustion air is supplied by a fan has become widespread. This is to forcibly supply the combustion air to the gas burner to achieve higher performance and smaller size of the equipment. In such a forced-fired water heater, it has been proposed to incorporate a waste heat recovery heat exchanger in the exhaust passage downstream of the heat exchanger to recover waste heat to improve thermal efficiency and lower the exhaust gas temperature. ing.

FIG. 4 is an overall configuration diagram of a water heater incorporating the waste heat recovery heat exchanger. In this water heater,
A fan 2 for blowing the combustion air sucked from the suction port 2a is attached to a combustion air supply passage 1, and a gas burner 3 is provided.
, A part of the blast air is sucked into the burner together with the combustible gas to burn. The heat exchanger is configured by placing an exchanger body 4 having a large number of fins fixed on the outer periphery of a heat receiving tube on an upper portion of an inner body 5, forming a combustion chamber inside the inner body 5, A preheating tube 6 is wound around the outer peripheral surface of the inner body 5 in order to cool the cooling unit 5 and preheat the former stage of the exchanger body 4. A waste heat recovery heat exchanger 8 is provided in an exhaust path 7 extending from the heat exchanger to an exhaust port 9.

[0004] Water supplied to the water heater is supplied to a preheating pipe 6.
After being heated by the exchanger body 4, it reaches the waste heat recovery heat exchanger 8, where it is heated again by the waste heat in the combustion exhaust gas passing through the exhaust passage 7 and is supplied with hot water. Then, the temperature is lowered to be discharged from the exhaust port 9. In this way, by collecting the waste heat contained in the combustion exhaust gas by the waste heat recovery heat exchanger 8, it is possible to improve the thermal efficiency of the appliance and to lower the temperature of the exhaust gas discharged outside the appliance, It is possible to reduce combustion exhaust of more than two hundred degrees to less than one hundred degrees, which is a useful means from the viewpoint of energy saving and environmental problems.

[0005]

The waste heat recovery heat exchanger 8 is interposed in a high-temperature exhaust passage 7, and the combustion exhaust gas is condensed at a low temperature to generate dew condensation. The drain adheres to the waste heat recovery heat exchanger 8, and the drain needs to be collected on a tray 10 provided at the bottom of the waste heat recovery heat exchanger 8 and subjected to detoxification treatment. Copper material, which is a general metal material for heat exchangers as a material for heat receiving tubes and fins,
A material that cannot be used because it is easily eroded by this drain and that absorbs waste heat by contacting the combustion exhaust, instead of copper, is made of aluminum or stainless steel that has corrosion resistance to the drain Is required. However, these alternative materials have problems in that joining by welding is difficult, the production cost of the heat exchanger is high, and aluminum is unsuitable for use as a hot water supply pipe that constantly passes water.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems. The heat exchanger 8 for recovering waste heat incorporated in the exhaust passage 7 is formed by using a corrosion-resistant material in a portion that comes into contact with the combustion exhaust gas. It is an object of the present invention to form and prevent erosion by a drain, and to reduce manufacturing costs by using manufacturing means instead of welding.

[0007]

In order to achieve this object, a heat exchanger for recovering waste heat of a water heater according to claim 1 is provided.
By cutting an aluminum material, a fin tube having a large number of fin ridges formed on the outer peripheral surface of the through hole is formed to a predetermined length, and a plurality of fin tubes are juxtaposed between stainless steel side plates.
Then, a copper water pipe is inserted into the through hole of the fin tube, the terminal of the water pipe is projected from the opening of the side plate, and the copper U-shaped pipe is joined to connect the terminal. With the above configuration, a portion that is in contact with the combustion exhaust gas is made of a corrosion-resistant material such as aluminum or stainless steel, so that erosion by the drain can be prevented.

According to a second aspect of the present invention, one end of the heat exchanger for recovering waste heat is abutted on the outer peripheral surface of the terminal tubular portion of the fin tube, and the other end is provided within the burring edge of the opening periphery. A stainless steel protection tube with the side inserted is provided on the outer periphery of the water flow tube, and the water flow tube is expanded, whereby the water flow tube, the protection tube, the fin tube, and the side plate are integrally joined and manufactured. By manufacturing in this manner, means such as welding and screwing are not required at all, and the manufacturing cost can be reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples. FIGS. 1 to 3 show a specific embodiment of the present invention, which is a waste heat recovery heat exchanger to be incorporated in the exhaust passage of the above-mentioned general configuration. In this waste heat recovery heat exchanger, an aluminum fin tube 20 having a through hole 22 formed in the shaft center and a plurality of fin ridges 21 formed on the outer peripheral surface of the through hole 22 is formed by cutting an aluminum material. It is formed to a predetermined length.

A plurality of the fin tubes 20 are juxtaposed between the stainless steel side plates 30, and a copper water pipe 23 is inserted into each through hole 22. The terminal portion 23a of the water pipe 23 protrudes from an opening 31 formed in the side plate 30, and is made of copper U.
The adjacent terminal portions 23a are connected by joining the pipes 25,
A hot water supply passage that flows through the water pipe 23 is formed to constitute a heat exchanger for waste heat recovery.

The production of this waste heat recovery heat exchanger is performed in the following steps. A water pipe 23 is inserted into the through hole 22 so as to be continuous with the terminal tubular portion 20a of the fin tube 20,
The outer peripheral surface of the water pipe 23 is covered with a protection pipe 27 made of stainless steel.
This protection tube 27 is provided on the outer periphery of the water pipe 23 with one end abutting on the outer peripheral surface of the terminal tubular portion 20a and the other end inserted into the burring edge 31a of the periphery of the opening 31. The water pipe 20 is set in the above-mentioned state, expanded by pressing the water pipe 20 in the radial direction from the axis (see FIG. 3), and the water pipe 23, the protection pipe 27, the fin tube 20, and the side plate 30 are simultaneously connected and joined. Integrate. Then, the U-shaped tube 25 is connected to the terminal unit 2.
3a and brazing, and the terminal 23a is connected. Since the U-shaped pipe 25 and the water pipe 23 are made of copper, the brazeability is good, and thus the water pipe 23 is made to communicate.

[0012]

As described above, the heat exchanger for recovering waste heat of a water heater according to the present invention has a copper water pipe 23 inserted into a through hole 22 of a fin tube 20 formed by cutting aluminum material. Since a plurality of fin tubes 20 are arranged side by side between the stainless steel side plates 30 in a double tube structure, aluminum and stainless steel corrosion-resistant materials are used in portions that come into contact with combustion exhaust and absorb waste heat. Thus, erosion by the drain can be prevented, and the durability can be improved.

According to the manufacturing means described in claim 2, it is possible to integrate the main members at once by plastic working for expanding the water pipe 23, and there is no means such as welding or screwing. Since it is unnecessary, the workability is excellent and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a perspective view of a terminal portion of a fin tube.

FIG. 3 is a sectional view of a main part showing a manufacturing process.

FIG. 4 is an overall configuration diagram of a water heater incorporating a waste heat recovery heat exchanger.

[Explanation of symbols]

 Reference Signs List 20 fin tube 20a terminal tubular portion 21 fin ridge 22 through hole 23 water pipe 23a terminal portion 25 U-shaped tube 27 protective tube 30 side plate 31 opening 31a burring edge

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[Procedure amendment]

[Submission date] January 18, 1999 (1999.1.1)
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004] The water supplied to this water heater is first discarded.
After being supplied to the heat exchanger 8 for heat recovery, it is exchanged from the preheating tube 6.
It is supplied to the container main body 4. Therefore, heat exchange for waste heat recovery
By the waste heat in the combustion exhaust gas passing through the exhaust passage 7
On the other hand, the combustion exhaust gas is heated in advance, the waste heat is recovered, the temperature of the combustion exhaust gas is reduced, and the exhaust gas is discharged from the exhaust port 9. In this way, by collecting the waste heat contained in the combustion exhaust gas by the waste heat recovery heat exchanger 8, it is possible to improve the thermal efficiency of the appliance and to lower the temperature of the exhaust gas discharged outside the appliance, It is possible to reduce combustion exhaust of more than two hundred degrees to less than one hundred degrees, which is a useful means from the viewpoint of energy saving and environmental problems.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shingo Kimura 3-4 Fukamidai, Yamato City, Kanagawa Prefecture Inside Gaster Co., Ltd. (72) Inventor Yuaki Akiba 3-4 Fukamidai, Yamato City, Kanagawa Prefecture Gaster Co., Ltd. (72) Inventor Akihisa Otomo 1-8-12, Miyamoto-cho, Kiryu-shi, Gunma, Japan Atago Seisakusho Co., Ltd. (72) Inventor Norio Tanihata 1-8-12 Miyamoto-cho, Kiryu-shi, Gunma, Japan Atago Manufacturing Co., Ltd. (Reference) 3L036 AA06 AA42 AE03

Claims (2)

[Claims] 1. A heat exchanger for recovering waste heat of a water heater to be incorporated into an exhaust passage of a forced combustion type water heater, wherein a plurality of fins are formed on an outer peripheral surface of a through hole (22) by cutting an aluminum material. Fin tube (20) having mountain (21)
Are formed to a predetermined length, a plurality of fin tubes (20) are juxtaposed between stainless steel side plates (30), and through holes (2) are formed.
2) Insert a copper water pipe (23) into the water pipe (2).
3) Open the end (23a) of the side plate (30) with the opening (31).
And a heat exchanger for recovering waste heat of a water heater in which a U-shaped tube (25) made of copper is joined and a terminal (23a) is connected. 2. A stainless steel protection in which one end abuts on an outer peripheral surface of a terminal tubular portion (20a) of a fin tube (20), and the other end is inserted into a burring edge (31a) of an opening (31). A pipe (27) is provided on the outer periphery of the water pipe (23), the water pipe (23) is expanded, and the water pipe (23), the protection pipe (27), the fin tube (20), and the side plate (3) are formed.
2. The heat exchanger for recovering waste heat of a water heater according to claim 1, wherein the heat exchanger is manufactured by integrally joining the heat exchangers.