JPH06281386A - Heat exchanger and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent generation of toxic gas by decreasing number of components to reduce a cost and reducing occurring rate of brazing malfunctions. CONSTITUTION:The heat exchanger comprises a cylindrical burner body 2 mounted at one end with a burner B, and an aluminum flat tube 3 for closing the other end opening of the body 2 and having a plurality of heating medium passages 4 therein. The exchanger further comprises right and left sidewalls 5a, a rear wall 5b for connecting rear edges of the sidewalls 5a, and an aluminum high temperature gas control member 5 brazed at front edges of the sidewalls 5a to a surface of the tube 3 toward the inside of the body 2. A zinc diffused layer is formed at a part directed toward the inside of the body 2 at a peripheral wall of the tube 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger used as, for example, an evaporator of a heating device, and more particularly to an evaporator for evaporating a heat medium such as freon by the combustion heat of an oil burner, a gas burner or the like. Heat exchanger and its manufacturing method.

In this specification, the lower side of FIG. 2 is referred to as the front and the opposite side is referred to as the rear. Further, the left and right in FIG. 2 are referred to as left and right. Further, in this specification,
The term "aluminum" is intended to include aluminum alloys in addition to pure aluminum.

[0003]

2. Description of the Related Art Heretofore, as this kind of heat exchanger, a cylindrical combustion cylinder having a burner attached to one end, an aluminum heat transfer partition for closing the other end opening of the cylindrical combustion cylinder, and an outer surface of the heat transfer partition An aluminum flat tube that is brazed to the inside and has a plurality of heat medium passages inside, a left and right side wall part, and a rear wall part that connects the rear edge parts of the left and right side wall parts, and the front of the left and right side wall part An aluminum high temperature gas flow restricting member whose edge is brazed to the inner surface of the heat transfer partition, and a zinc diffusion layer is formed on the rearward facing portion of the peripheral wall of the heat transfer partition and the flat tube. Is known (see, for example, Japanese Patent Laid-Open No. 4-36591).

[0004]

However, in the conventional heat exchanger, since the heat transfer partition wall and the flat tubes are brazed over a wide area, the rate of defective brazing is increased and the brazing failure is increased. It is difficult to understand the attachment status. Further, since the combustion cylinder, the heat transfer partition, the flat tube and the high temperature gas flow restricting member are required, there is a problem that the number of parts is increased.

An object of the present invention is to provide a heat exchanger and a method for manufacturing the same that solve the above problems.

[0006]

A heat exchanger according to the present invention has a cylindrical combustion cylinder having a burner attached to one end thereof, a second end opening of the cylindrical combustion cylinder closed, and a plurality of heat transfer medium passages provided therein. The aluminum flat tube has a rear wall that connects the left and right side walls and the rear edges of the left and right side walls, and the front edges of the left and right side walls are on the surface of the flat tube facing the inside of the combustion cylinder. And a zinc high temperature gas flow restricting member attached thereto, and a zinc diffusion layer is formed on a portion of the peripheral wall of the flat tube facing the inside of the combustion cylinder.

In the first method for manufacturing a heat exchanger according to the present invention, a cylindrical combustion cylinder having a burner attached to one end, the other end opening of the cylindrical combustion cylinder is closed, and a plurality of heat medium passages are provided inside. The aluminum flat tube has a rear wall that connects the left and right side walls and the rear edges of the left and right side walls, and the front edges of the left and right side walls are on the surface of the flat tube facing the inside of the combustion cylinder. A method for manufacturing a heat exchanger having an attached aluminum high temperature gas flow restricting member, wherein the flat tube and the high temperature gas flow restricting member are made of an aluminum sheet brazing filler material containing zinc. It is characterized by being attached.

In the second method for manufacturing a heat exchanger according to the present invention, a cylindrical combustion cylinder having a burner attached to one end, the other end opening of the cylindrical combustion cylinder is closed, and a plurality of heat medium passages are provided inside. The aluminum flat tube has a rear wall that connects the left and right side walls and the rear edges of the left and right side walls, and the front edges of the left and right side walls are on the surface of the flat tube facing the inside of the combustion cylinder. A method of manufacturing a heat exchanger having an attached high temperature gas flow control member made of aluminum, wherein a galvanized layer is formed in advance on the surface of the flat tube that faces the inner side of the combustion cylinder, and the flat tube and The high temperature gas flow restricting member is brazed using an aluminum sheet brazing material.

[0009]

Since the opening of the other end of the cylindrical combustion cylinder, to which the burner is attached at one end, is closed by the flat tube made of aluminum having a plurality of heat transfer medium passages inside, the heat transfer partition in the conventional heat exchanger is unnecessary. become. Further, since the high temperature gas flow restricting member having the rear wall portion connecting the left and right side wall portions and the rear edge portions of the left and right side wall portions is brazed to the flat pipe at the front edge portions of the left and right side wall portions, The area of the brazing part is smaller than that of the heat exchanger. Furthermore, since the zinc diffusion layer is formed on the portion of the peripheral wall of the flat tube facing the inside of the combustion cylinder, the zinc diffusion layer is sacrificed by surface corrosion on aluminum, and the zinc diffusion layer faces the inside of the combustion cylinder on the peripheral wall of the flat tube. The occurrence of pitting corrosion on the exposed portion is prevented.

When the flat tube and the high-temperature gas flow restricting member are brazed by using an aluminum sheet brazing material containing zinc, the zinc in the brazing material is heated by the brazing material so that the zinc in the brazing material is formed on the peripheral wall of the flat tube. It is diffused in the part facing inward,
A zinc diffusion layer is formed here.

When a galvanized layer is formed in advance on the surface of the flat tube that should face the inside of the combustion cylinder, and the flat tube and the high-temperature gas flow restricting member are brazed using an aluminum sheet brazing material, brazing is performed. By heating at this time, zinc in the galvanized layer is diffused to a portion of the peripheral wall of the flat tube facing the inside of the combustion cylinder, and a zinc diffusion layer is formed there.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show a heat exchanger 1 according to the present invention.
An example is shown.

1 to 3, a heat exchanger (1) is attached to a lateral cylindrical combustion cylinder (2) having both ends open, and is attached to a rear end opening of the combustion cylinder (2) to collect oil, gas and the like. Burner (B) used as fuel and multiple heat medium passages extending vertically inside
An aluminum flat tube (3) having (4) and closing the front end opening of the combustion cylinder (2), and an aluminum hot gas flow brazed to the rearward facing surface of the flat tube (3). Control member
(5) and are equipped. Flat tube (3) and high temperature gas flow control member
The brazing material brazing (5) and (13) is shown.

The combustion cylinder (2) is a cylindrical portion formed below
(2a) and an expanding portion (2b) formed at the front end of the cylindrical portion (2a) are provided, and the inside of the cylindrical portion (2a) serves as a combustion chamber.
The inner peripheral surface of the cylindrical portion (2a) is covered with a heat insulating material (6). A high temperature gas flow restricting member (5) is arranged in the expanding portion (2b). The upper end of the high temperature gas flow restricting member (5) is located below the upper end of the expanding portion (2b), and the lower end is located above the lower end of the expanding portion (2b). An exhaust pipe (7) extending rearward is connected to the upper end of the expansion portion (2b) of the combustion cylinder (2). Also,
An outward flange (2c) is formed at the front end of the expansion portion (2b).

A zinc diffusion layer (8) is formed on the portion of the peripheral wall of the flat tube (3) facing the rear side. Overhangs (3a) are formed on both left and right edges of the flat tube (3), and the overhang (3a) is formed on the left and right sides of the flared portion (2b) of the expansion part (2b) of the combustion cylinder (2). The parts near both edges are fixed with screws and rivets. The upper and lower ends of the flat tube (3) are connected to the headers (9) and (10), respectively. Lower header (1
0) is an inlet side header, and a heat medium inlet pipe (not shown) is connected to the left end portion thereof. The oil of the compressor is always dissolved in the heat medium, and when the heat medium is vaporized by heating, this oil gradually accumulates, and its viscosity and low heat transfer hinder vaporization and circulation of the heat medium, so prevent this. For the purpose, an oil drain pipe (not shown) is connected to the right end of the inlet header (10). The header (9) on the upper side is an outlet side header, and the heat medium outlet pipe (not shown) is connected to the left end portion thereof. Long holes (9a) (10a) that extend in the axial direction are formed in the peripheral walls of both headers (9) (10), and the upper and lower ends of the flat tube (3) are located in these long holes (9a) (10a). ) And is inserted into the header (9) (10), and is brazed to the peripheral wall of the header (9) (10).

The high temperature gas flow restricting member (5) is made of an aluminum extruded shape member, and has left and right side walls (5a) extending in the vertical direction.
A rear wall portion (5b) that connects the rear edge portions of the left and right side wall portions (5a),
And an intermediate wall portion (5c) connecting the central portions of the widths of the left and right side wall portions (5a). A passage (11) extending in the vertical direction is formed on the front surface of the left and right side wall portions (5a). The first heat transfer fin (5d) and the second heat transfer fin (5d) are arranged between the rear wall portion (5b) and the intermediate wall portion (5c) and on the front surface of the intermediate wall portion (5c) at right angles thereto. (5e) are provided integrally, and both heat transfer fins (5d) and (5e) adjacent to each other and both heat transfer fins (5e)
The part between d) (5e) and the left and right side walls (5a) is the passage (1
2) It is said that. The high temperature combustion exhaust gas flows in the passages (11) and (12). The high temperature gas flow restricting member (5) is arranged so as to be slightly higher than the upper and lower intermediate parts, and the front edges of the second heat transfer fins (5e) and the left and right side walls (5a) are flat. It is brazed to the pipe (3), and the front end peripheral edge of the cylindrical portion (2a) is in contact with the rear surface of the rear wall portion (5b). Therefore, the high-temperature combustion exhaust gas generated in the combustion cylinder (2) flows from the lower end of the high temperature gas flow restricting member (5) to the passages (11) (1).
2) It flows in and flows upward.

In such a structure, the combustion gas of the burner (B) passes from the lower end of the high temperature gas flow restricting member (5) to the passage (11).
The exhaust pipe (7) enters the inside of (12), flows upward in the passages (11) and (12), and further passes through a portion above the high temperature gas flow restricting member (5) in the expansion portion (2b). Emitted from. The heat of the exhaust gas flows through the passages (11) and (12) of the high temperature gas flow restricting member (5) either directly or through the heat transfer fins (5d) and (5e), and then to the flat pipe.
(3), passing through the peripheral wall of the flat tube (3)
(4) Transferred to the heat medium flowing inside. The heating medium is a burner (B)
It is heated and vaporized by the heat of combustion of, and the latent heat is used for heating. At this time, first, the heat medium is a flat tube.
The lower part of the inside of (3) is heated and partially vaporized, and the action of the vaporized heat medium naturally rises in the heat medium passage (4) and the whole is vaporized.

A first embodiment of the method of manufacturing the heat exchanger (1) is shown in FIG.

In FIG. 4, a flat tube (3), a high temperature gas flow restricting member (5), headers (9) and (10) and an aluminum sheet brazing material (15) containing zinc are prepared in advance.

Then, the front edge portion of the second heat transfer fins (5e) and the front edge portions of the left and right side wall portions (5a) of the high temperature gas flow restricting member (5) are flattened with a sheet-like brazing material (15) interposed therebetween. (3) Close them to the rear surface and fix them with an appropriate jig. Also, flat tubes (3)
Around the upper and lower ends of the header (9) (10)
a) Place the brazing filler metal over (10a) and fix them with an appropriate jig. After that, the flat tubes (3), the second heat transfer fins (5e) of the high temperature gas flow restricting member (5) and the left and right side walls (5a),
And the flat tubes (3) and the headers (9) and (10) are brazed respectively. Due to the heating during the brazing process, the zinc contained in the sheet-shaped brazing filler metal (15) is diffused into the aluminum at the rear side of the peripheral wall of the flat tube (3) to prevent corrosion. A diffusion layer (8) is formed. Further, the heat exchanger (1) is manufactured by fixing the flat tube (3) to the combustion cylinder (2) with screws, rivets or the like.

FIG. 5 shows a second manufacturing method of the heat exchanger.

In FIG. 5, a galvanized layer (20) is formed in advance on the surface of the flat tube (3) facing the rear side. Also,
Flat tube (5), high temperature gas flow control member (5), header (9) (10)
Also prepare an aluminum sheet brazing material (21).

The flat edges of the front edges of the second heat transfer fins (5e) and the front edges of the left and right side walls (5a) of the high temperature gas flow restricting member (5) are sandwiched by the sheet-like brazing material (21). (3) Close them to the rear surface and fix them with an appropriate jig. Also, flat tubes (3)
Around the upper and lower ends of the header (9) (10)
a) Place the brazing filler metal over (10a) and fix them with an appropriate jig. After that, the flat tubes (3), the second heat transfer fins (5e) of the high temperature gas flow restricting member (5) and the left and right side walls (5a),
And the flat tubes (3) and the headers (9) and (10) are brazed respectively. Due to the heating during the brazing process, zinc in the zinc plating layer (20) is diffused into aluminum in the rear part of the peripheral wall of the flat tube (3), and a zinc diffusion layer (8) for corrosion protection is provided. Is formed. In addition, screw the flat tube (3),
The heat exchanger (1) is manufactured by fixing it to the combustion cylinder (2) with rivets or the like.

In the above embodiment, the combustion gas flows from the lower part to the upper part in the passages (11) and (12) of the high temperature gas flow restricting member (5). In order to reverse the flow direction of the medium and the flow direction of the combustion gas, the flow in the passages (11) and (12) of the high temperature gas flow restriction member (5) is made to flow downward from the above, contrary to the above. Good. In this case, the hot gas flow restricting member (5) is placed slightly below the upper and lower intermediate parts, and the exhaust pipe (7) is connected to the expansion part (2
Connect to the lower end of b).

[0026]

As described above, according to the heat exchanger of the present invention, since the heat transfer partition wall in the conventional heat exchanger is unnecessary, the number of parts is reduced and the cost is reduced. Also,
Since the area of the brazing portion between the high temperature gas flow restricting member and the flat tube is small, the incidence of brazing defects is reduced. Moreover,
Since the brazing state can be easily grasped, even if a brazing defect occurs, it can be repaired. Furthermore, since the zinc diffusion layer is formed on the surface of the flat tube facing the inner side of the combustion cylinder, the zinc diffusion layer is sacrificed by surface corrosion on aluminum, and the portion of the peripheral wall of the flat tube facing the inner surface of the combustion tube is sacrificed. The occurrence of pitting corrosion is prevented. Therefore, the heat medium such as Freon flowing in the flat tube enters the combustion cylinder, and the reaction between the heat medium and the combustion gas is prevented, whereby the generation of toxic gas due to this reaction is prevented.

According to the two manufacturing methods of the present invention, the zinc in the brazing material is diffused into the portion of the peripheral wall of the flat tube facing the inside of the combustion cylinder by heating during brazing,
Since the zinc diffusion layer is formed here, as described above,
It is possible to prevent pitting corrosion from occurring in the portion of the peripheral wall of the flat tube facing the inside of the combustion cylinder. Therefore, the heat medium such as Freon flowing in the flat tube enters the combustion cylinder, and the reaction between the heat medium and the combustion gas is prevented, whereby the generation of toxic gas due to this reaction is prevented.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a heat exchanger according to the present invention.

FIG. 2 is a horizontal sectional view with a part omitted.

FIG. 3 is a partially enlarged view of FIG.

FIG. 4 is a diagram showing a first embodiment of the heat exchanger manufacturing method of the present invention.

FIG. 5 is a drawing showing a second embodiment of the heat exchanger manufacturing method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Cylindrical combustion barrel 3 Flat tube 4 Heat medium passage 5 High temperature gas flow control member 8 Zinc diffusion layer 15 Aluminum sheet brazing material containing zinc 20 Zinc plating layer 21 Aluminum sheet brazing material B Burner

Claims (3)

[Claims] 1. A tubular combustion cylinder having a burner attached to one end thereof, an aluminum flat tube having a plurality of heat transfer medium passages therein, the other end opening of the tubular combustion cylinder being closed, and left and right side wall portions and left and right sides. A high temperature gas flow control member made of aluminum, which has a rear wall portion connecting the rear edge portions of the side wall portions, and the front edge portions of the left and right side wall portions are brazed to the surface of the flat tube facing the inside of the combustion cylinder. And a zinc diffusion layer is formed on a portion of the peripheral wall of the flat tube facing the inner side of the combustion cylinder. 2. A cylindrical combustion cylinder having a burner attached to one end thereof, an aluminum flat tube having a plurality of heat transfer medium passages therein, the other end opening of the cylindrical combustion cylinder being closed, and left and right side wall portions and left and right sides. A high temperature gas flow control member made of aluminum, which has a rear wall portion connecting the rear edge portions of the side wall portions, and the front edge portions of the left and right side wall portions are brazed to the surface of the flat tube facing the inside of the combustion cylinder. A method of manufacturing a heat exchanger comprising: a flat tube and a high temperature gas flow restricting member, which are brazed using an aluminum sheet brazing material containing zinc. Method. 3. A cylindrical combustion cylinder having a burner attached to one end thereof, an aluminum flat tube having a plurality of heat transfer medium passages therein and closing the other end opening of the cylindrical combustion cylinder, and left and right side wall portions and left and right side portions. A high temperature gas flow control member made of aluminum, which has a rear wall portion connecting the rear edge portions of the side wall portions, and the front edge portions of the left and right side wall portions are brazed to the surface of the flat tube facing the inside of the combustion cylinder. A method for manufacturing a heat exchanger comprising: a flat tube having a galvanized layer formed in advance on the surface of the flat tube that faces the inner side of the combustion cylinder, and the flat tube and the high-temperature gas flow restricting member being made of an aluminum sheet. A method for manufacturing a heat exchanger, which comprises brazing using a brazing material.