JPH09159388A - Method of manufacturing heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity of heat exchanger by forming U shape cut outs on fins, inserting heat absorbing tubes into the cut outs, brazing between the inner edge part of each cut out and each heat absorbing tube inserting the heat absorbing tubes into the cut outs and eliminating the tube expanding step of the heat absorbing tube. SOLUTION: On fins 2, U shape cut outs 21, of which forms of inner edges conform the outer circumferences of the cross sections of heat absorbing tubes 1, are arranged and the heat absorbing tubes 1 are inserted into the U shape cut out parts 21 from the opening sides. In inserting the heat absorbing tubes 1, each fin and each heat absorbing tube 1 are brazed along the inner edge part of each cut out part 21 for a predetermined length. Therefore, the tube expanding step is eliminated and the productivity of the heat exchanger is improved, and by setting the posture of the fins 2 group so that the cut outs of the fins 2 group are directed towards the down flow side of the flow of combustion exhaust, the heat absorbing efficiency from the fins 2 group is prevented from lowering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a heat exchanger, and more particularly to a method for manufacturing a heat exchanger of the type in which a large number of fin groups and heat absorbing tubes that penetrate these fins are brazed.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a heat exchanger made of stainless steel, there has been one shown in FIGS. In this product, a nickel tape-shaped brazing material (3) (3) having good brazing performance for stainless steel is spirally wound around the endothermic tubes (1) (1). Then, the heat absorption tube (1) (1) in this state through the through hole (29) provided in the fin (2) (2) group
(29), and then the rod-shaped mold is pushed into the heat absorbing tube (1) (1) to enlarge the cross section of the heat absorbing tube (1) (1). By this tube expanding step, the outer circumference of the heat absorbing tube (1) (1) and the peripheral edge of the through holes (29) (29) become along the entire circumference, and the brazing material (3 ) (3) is closely intervened. Therefore, after this, when the brazing material (3) (3) is heated and melted, the outer circumference of the heat absorbing tube (1) (1) is brazed to the fins (2) (2) group over the entire circumference. It has been done.

[0003]

However, in this conventional technique, there is a problem that the heat expansion of the heat exchanger is not good because of the tube expanding step. Therefore, in order to eliminate the pipe expanding step, the through holes (29) (29) are set to a predetermined size, and the heat absorbing tubes (1) (1) are connected to the through holes (29) (2).
A method of forcibly pressing into 9) can be considered. However, in this case, the brazing material (3) (3) on the surface of the heat absorbing tube (1) (1) and the inner peripheral edge of the through holes (29) (29) should be rubbed strongly over the entire circumference. Therefore, a large force is required to push the heat absorbing tubes (1) (1), and the brazing materials (3) (3) are easily displaced or broken.

In view of such a point, the invention of claim 1 has the following features.
In the "method of manufacturing a heat exchanger of the type in which a fin (2) (2) group in which fins are arranged in parallel and a heat absorbing tube (1) orthogonal to this group are brazed", the heat absorbing tube (1) ( The object is to improve the productivity of the heat exchanger by eliminating the pipe expanding step of 1).

[0005]

[Means for Solving the Problems] According to the means for solving the problems of the invention of claim 1, "in the fin (2), the shape of the inner end portion is set to follow the outer circumference of the cross section of the heat absorbing tube (1)." U-shaped cutouts (21) (21) are provided, and the heat absorption tube (1) is inserted into each cutout (21), and the cutouts are in this inserted state.
The inner end of (21) and the endothermic tube (1) are brazed ”.

In this structure, the heat absorbing tube (1) is inserted into the cutouts (21) (21) of the fins (2) (2) group from the open side thereof, and the cutouts (1) are inserted in this inserted state. 21) The end portions of (21) and the endothermic tube (1) are brazed. At this time, since the shape of the inner end of the cutouts (21) (21) is set along the outer periphery of the cross section of the heat absorption tube (1), the fins
(2) The heat absorbing tube (1) and the heat absorbing tube (1) are brazed over a certain length along the inner ends of the cutouts (21, 21).

Here, in order to "braze the inner end portion of the cutout portion (21) and the endothermic tube (1)" in the above-mentioned claim 1, the invention according to claim 2 is adopted. As described above, “the endothermic tube (1) is inserted into the inner end of the notch (21) so that the brazing material (3) having a constant thickness is interposed between them, and , The whole is heated ”. In this case, the heat absorption tube (1) and the notch (2
Since a brazing material (3) having a certain thickness is interposed between the brazing material (3) and the inner end portion of (1), the brazing material (3) is heated and melted, so that the heat absorbing pipe (1) and the inner end portion are And are brazed over a certain length along the boundary.

In addition, "the fin (2) (2) group of the notch (2
1) A recess is provided at the innermost end of the inner end of (21), and a linear brazing material penetrates the recess with the heat absorption tube (1) inserted in the inner end, After this, the notch (21)
(21) is configured to heat the whole in a posture in which it is opened downwards. " In this, the whole is heated in a state where the linear brazing material penetrating the recess is located at the uppermost part of the notches (21) (21). Thereby, the brazing material is melted and flows downward along the peripheral edge of the inner end portion,
The inner end portion is brazed over a certain length.

Further, in order to obtain the "state in which the brazing material (3) having a constant thickness is densely interposed" in the second aspect of the invention, the endothermic pipe ( Form a brazing material coating pipe (1a) in which tape-shaped brazing material (3) is wound in a spiral shape on (1), and cut the brazing material coating pipe (1a) into the notch (2).
1) It may be inserted in (21). Further, as in the invention of claim 3, "the heat absorption tube (1) in a substantially horizontal posture is the cutout portion (21) opened upward or downward in the fin (2) (2) group. It is to be inserted vertically with respect to (21), and at this time, the brazing material (3) is supported by a member below the heat absorbing tube (1) or the fins (2). " It may be one.

Further, as in the invention of claim 4, "in the state where the endothermic pipe (1) is inserted into the inner end portion of the cutout portion (21), the brazing material (3) is attached to the endothermic pipe (3). 1) and the fin
In the configuration "press-fitted between (2)", the heat-absorbing tube (1) is temporarily fixed to the fins (2), (2) by the press-fitting. Like the invention of claim 5,
In the case of `` the outside of the inner end of the cutout portion (21) is set to a size such that the heat absorption tube (1) can be inserted with a margin '', the heat absorption tube (1) is formed into the cutout portion (1). When inserted into 21), the heat absorbing tube (1) and the fins (2) and (2) are unlikely to rub at least up to the inner end.

According to the invention of claim 6, "the notch (2
At the peripheral edge of the inner end of 1), along the edge of the endothermic pipe
(1) a projecting piece (23) is provided which is substantially parallel to the axis of (1) '', and when the endothermic tube (1) is inserted into the inner end of the notch (21), the inner end Since the protruding piece (23) protruding along the peripheral edge of the fin is attached along the outer circumference of the cross section of the heat absorbing tube (1), the fins (2) (2) and the heat absorbing tube (1) The brazing area with and becomes large.

[0012]

As described above, according to the first aspect of the invention, the tube expanding step as in the above-mentioned conventional technique is unnecessary, and the productivity of this heat exchanger is improved. Also, endothermic tube (1)
And fins (2) (2) group are brazed along the peripheral edge of the inner end of the notch (21) (21) for a certain length, so that the fins (2) (2) group Sufficient brazing strength between the heat absorbing tube (1) and the heat absorbing tube (1) is secured.

The heat exchanger manufactured according to the first aspect of the present invention is the heat exchanger tube in the fin (2) (2) group.
(1) The fins (2)
(2) When the posture of the fins (2) and (2) is set so that the cutout part of the group faces the downstream side of the flow of combustion exhaust gas, the fins
(2) The heat absorption efficiency from the group (2) does not easily decrease. According to a third aspect of the present invention, the brazing material is used as a lower member of the heat absorbing tube (1) and the fins (2) and (2) in which the heat absorbing tube (1) is inserted in a substantially horizontal position.
Since it is only necessary to place (3), as compared with the case where the tape-shaped brazing material (3) is spirally wound around the heat absorbing tube (1) as in the conventional technique described above, the brazing material (3 ) Is a simple process for interposing.

In the invention of claim 4, the heat absorbing pipe (1) is inserted into the inner end of the notch (21) so that the heat absorbing pipe (1) becomes the fin (2) (2) group. On the other hand, since they are temporarily fixed, it is possible to prevent the deviation between the two from the temporarily assembled state to the brazing. In the invention of claim 5, when the heat absorbing pipe (1) is inserted into the cutout portion (21), the heat absorbing pipe (1) and the cutout portion (21) are less likely to be rubbed, so that the inserting operation is performed. It will be smooth.

According to the sixth aspect of the invention, the area of brazing between the endothermic pipes (1) is increased in the state where the endothermic pipes (1) are inserted into the inner end portions of the cutout portions (21). 1)
And the brazing strength between the fins (2) and (2) group becomes large. Also, the thermal conductivity from the fins (2) (2) to the heat absorbing tube (1) is improved.

[0016]

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. In this embodiment, as shown in FIG. 4 and FIG. 5, a plurality of stainless steel heat absorption tubes (1) (1) are arranged in upper and lower three stages in a rectangular box-shaped can body (4). Do not braze the fins (2) (2) made of stainless steel to the heat absorption pipes (1) (1) in the middle stage, and do not install the fins (2) (2) in the heat absorption pipes (1) (1) in the lower stage. The heat exchanger of the above type was manufactured.

As shown in FIGS. 3 and 4, each fin (2) has a plurality of first cutouts deeply cut from below for brazing the upper end heat absorbing tubes (1) (1). (211) (211), and
In order to braze the heat absorption tubes (1) (1) in the middle stage between the first notches (211) (211), a plurality of second shallow cuts are made from below.
Notches (212) (212) are provided. Also, the inner ends of the first notches (211) and (211) are semi-circular semi-circular arcs (201) (20
1), and the inner end portions of the second cutout portions (212) (212) are similar semi-circular arc portions (202) (202). One of the first
The portions of the notches (211) (211) below the semi-circular arc portions (201) (201) are shaped so as to expand downward, and the other second notches (212) ( 212) is the semi-circular portion (2
02) (202) only. Any of the semi-circular arc portions (201)
The radius of the (202) is also set to be slightly smaller than the sum of the radius of the heat absorbing tubes (1) and (1) and the thickness of the brazing material (3) described later.

Further, on one surface of the fins (2) (2), a protruding piece (23) (having a substantially semicircular cross section, which protrudes in a substantially horizontal direction along the periphery of the semi-circular arc portions (201) (202) ( 23) is provided. The height of these protruding pieces (23) (23) is set to a height that substantially matches the arrangement interval of the fins (2) (2). Also, the fin
(2) At the left and right edges of the one surface of (2), the protruding pieces (23) (2
Bending pieces (24) (24) having the same height as 3) are connected in series.

The above-mentioned upper and middle endothermic tubes
(1) (1) and the fins (2) and (2) group are integrally assembled by the following steps. In addition, in this process,
As shown in FIG. 5, there is used a holding plate (5) on the upper surface of which a large number of thin grooves (51) (51) for holding the above-mentioned fins (2) (2) group upright are arranged. The arrangement pitch of the narrow grooves (51) (51) corresponds to the arrangement pitch of the fins (2) (2) in the completed state of the heat exchanger, and the width of each narrow groove (51) is It is approximately equal to the wall thickness of the fin (2). Further, on the outside of the group of the narrow grooves (51) (51), a plurality of upright pieces (52) (52) which stand upright so as to match the outer edges of the narrow grooves (51) (51) at both ends thereof. Is projected.

First, as shown in FIGS. 1 and 2, the holding plate for holding the fins (2) and (2) in a posture in which the first and second cutouts (211) and (212) are open upward. Insert it into the narrow groove (51) (51) group of (5). At this time, the narrow groove (51) (51) group, the protruding piece
(23) (23) and the bent pieces (24) and (24) make the arrangement interval of the fins (2) and (2) match that of the completed state. In addition, the fins are formed by the upright pieces (52) (52).
(2) The entire group (2) will be held in a vertical position.

Next, in the first and second notches (211) and (212) opened upward, a nickel tape formed in a tape shape long in the direction in which the fins (2) and (2) are arranged side by side. The brazing material (3) is inserted so that the brazing material (3) is attached to substantially the entire periphery of the semi-circular arc portions (201) and (202). On the other hand, the endothermic pipes (1) (1) of each stage are housed in the can body (4), and the endothermic pipes (1) (1) exposed through the side wall of the can body (4) are exposed. The U-shaped bending pipes (11) (11) are connected to the ends. Then, a brazing filler metal (around the entire circumference of the fitting portion between the can body (4) and the heat absorbing pipe (1) and the connecting portion between the bending pipe (11) and the heat absorbing pipe (1). 3) intervene closely.

Then, as shown in FIG. 1, the heat absorption tubes (1) and (1) incorporated in the can body (4) are placed above the first and second cutouts (211) and (212). When inserted from
(201) (202) peripheral edge of the protruding piece (23) (23) and the endothermic tube
(1) The brazing material (3) is densely interposed between the cross-section outer periphery of (1). Further, the heat absorbing tubes (1) (1) are connected to the protruding pieces (2
3) The brazing filler metal (3) is sandwiched between the fins (2) and (2) and the endothermic tubes (1) and (1) are temporarily fixed to the inner peripheral area of (23). .

This temporary assembly is set on the holding plate (5) and put in a heating furnace. As a result, the brazing filler metal (3) is heated and melted, and the heat absorbing tubes (1) (1) and the fins (2) (2) group are formed over substantially the entire area of the protruding pieces (23) (23). It will be brazed over. Further, the connecting portion between the bent pipe (11) and the heat absorbing pipe (1) and the fitting portion between the heat absorbing pipe (1) (1) and the can body (4) are brazed. Become.

In this case, the cross section of the heat absorbing tubes (1) (1) and the semi-circular arc portions (201) (202) are brazed over a constant length in the circumferential direction. , Its brazing strength is sufficiently secured. Further, since the protruding pieces (23) (23) and the heat absorbing tubes (1) (1) are brazed and the brazing area is increased, the brazing strength is also increased in this respect. Incidentally, the protruding pieces (23) (23) may be omitted.

After removing the brazed product from the heating furnace and cooling it, the holding plate (5) is removed to complete a heat exchanger having a water pipe formed in a meandering shape. In this embodiment, the first and second cutouts (211) (212) are the cutouts (21) (21) described in claim 1. * Other embodiments *. In the above-mentioned embodiment, the tape-shaped brazing material (3) is used, but this is applied by covering the whole area of the fins (2) (2) with the wide sheet-shaped brazing material (3). Good. In this case, the size of the brazing material (3) is such that all the semi-circular arc portions (201) (201) (201) (1) (1) are inserted in the semi-circular arc portions (201) (202). The size of the brazing material (3) is set in 202).

.. A linear brazing material (3) can also be used. In this case, as shown in FIG. 6, with the heat absorption tubes (1) and (1) inserted in the notches (21) and (21) of the fins (2) and (2), the notches (21) A small recess (2
5) The method in which the above-mentioned linear brazing material (3) penetrates into (25), and then the whole is heated with the notches (21) and (21) opened downward. it can. In this case, when the brazing material (3) is heated and melted, the brazing material
(3) flows downward at the boundary between the cutouts (21) and (21) and the outer circumference of the heat absorbing pipe (1) (1), and the heat absorbing pipes (1) (1) and the fins (2)
The group (2) is brazed along the peripheral edges of the cutouts (21) and (21) over a certain length.

A paste-like brazing material (3) can also be used. In this case, as shown in FIG.
(2) (2), with the cutouts (21) and (21) in a posture in which the cutouts (21) and (21) are opened upward, after inserting the heat absorption pipe (1) into each cutout (21),
The brazing material (3) is provided in a concave portion formed between the heat absorbing tube (1) and both ends of the protruding piece (23) on the periphery of the cutout portion (21).
Can be adopted. Also in this method, the brazing material
(3) flows downward through the boundary portion between the cutout portion (21) and the outer circumference of the cross section of the heat absorbing tube (1) due to its heating and melting, and both are brazed.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a method for manufacturing a heat exchanger according to an embodiment of the present invention.

[Fig. 2] Side view of the fins (2) and (2) set on the holding plate (5).

FIG. 3 is a plan view of the fin (2)

FIG. 4 is a sectional view of the heat exchanger.

FIG. 5 is a plan view of the heat exchanger.

FIG. 6 is an explanatory diagram of another embodiment.

FIG. 7

FIG. 8 is a cross-sectional view of a heat exchanger manufactured by a conventional technique.

FIG. 9 is an explanatory view of the manufacturing process of the conventional technique.

[Explanation of symbols]

 (2) ・ ・ ・ Fins (1) ・ ・ ・ Endothermic tube (21) ・ ・ ・ Notch (3) ・ ・ ・ Brazing material (23) ・ ・ ・ Projecting piece

Claims (6)

[Claims] 1. A method of manufacturing a heat exchanger of the type in which a group of fins (2) (2) having fins arranged in parallel and a heat absorbing tube (1) orthogonal to the group are brazed. ), The shape of the inner end is the endothermic tube (1)
U-shaped notch (21) set to follow the outer circumference of the cross section
(21) is provided, and the heat absorption tube (1) is inserted into each notch (21), and the inner end of the notch (21) and the heat absorption tube (1) are inserted in this inserted state. A method for manufacturing a heat exchanger to be brazed. 2. The endothermic tube (1) is inserted into the inner end of the notch (21) so that a brazing material (3) having a constant thickness is interposed between them. After that, the method for manufacturing the heat exchanger according to claim 1, wherein the whole is heated. 3. The endothermic tube (1) in a substantially horizontal position is placed above and below the notch (21) (21) opened upward or downward in the fins (2) (2) group. 3. The heat exchange according to claim 2, wherein the brazing material (3) is supported by a lower member of the heat absorbing tube (1) or the fin (2) at this time. Manufacturing method. 4. The brazing filler metal (3) is connected to the heat absorbing tube (1) and the fin (2) in a state where the heat absorbing tube (1) is inserted into the inner end portion of the cutout portion (21). The method for manufacturing a heat exchanger according to claim 2, wherein the heat exchanger is press-fitted in between. 5. The size according to claim 1, wherein an outer side of the inner end of the cutout portion (21) is set to a size into which the heat absorbing tube (1) is inserted with a margin. Heat exchanger manufacturing method. 6. A projecting piece (23) protruding substantially parallel to the axis of the heat absorbing tube (1) along the peripheral edge of the inner end of the cutout (21). The manufacturing method of the heat exchanger in any one of Claims 1-4.