JPS6225958B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cross-finch tube heat exchanger having bends.

Recently, efforts have been made to save energy in air conditioning equipment, and heat exchangers have been required to be larger in size and have lower ventilation resistance. On the other hand, from an economic point of view, there are demands for a small installation area and a small cabinet, and in order to meet these conflicting demands, conventional heat exchangers with curved parts as shown in Figure 1 have been developed. It is being adopted.

In FIG. 1, 1 is a fin, 2 is a hairpin pipe, and 3 is a bend pipe. By bending the hairpin pipe 2, a bent portion is created.

The heat exchanger shown in Fig. 1 is made by bending a general heat exchanger as shown in Fig. 2 using the method shown in Fig. 3 using a tangential bender that causes the least damage to the fins. was.

In FIG. 3, numeral 4 is a lower die solidified to the bender body, 5 is an upper die attached to the ram of the bender, and 6 is a bending die attached to the wing of the bender.

For bending, attach the heat exchanger 7 to the lower die 4, and then attach the heat exchanger 7 to the upper die 5.
The bending die 6 is then rotated at the R portion of the bending die 6 while rolling tangentially into contact with the heat exchanger 7.

However, even with this method, the bending moment for bending the pipe is applied from the fin end face, and if the bending radius is too small, the fin end face may collapse.

Further, since the pipe 2 is not directly restrained, if a hard thin-walled pipe is used, it will buckle, so a work-hardened pipe cannot be used. Furthermore, since the fin pitch becomes narrower in a tapered shape inside the bent R portion, the ventilation resistance increases at that portion.

In any case, since the bending radius can only be quite large, the area where the ventilation resistance increases will increase considerably, and the tube expansion in that area will also become somewhat loose, so the heat transfer performance as a heat exchanger is as shown in Figure 2. considerably lower than that of Also, since the bending radius is large,
If it is housed in the cabinet 9 as shown in FIG. 4, the space at 10 will be wasted. In the figure, 11 is a compressor, and 12 is a fan.

It becomes even more troublesome when there are two or more rows of pipes, as in the heat exchanger shown in Figure 5. In the case of two rows of pipes, it is impossible to bend them after expansion, so it is necessary to expand only one row, bend it, and then expand the remaining rows again using hydraulic pressure, which greatly reduces productivity. For this reason, as shown in Figure 6, 1
You can stack two row heat exchangers and bend them, or you can stack two of the same length and bend them as shown in Figure 7.

In the case of Fig. 6, it is necessary to make two heat exchangers before bending, and in the case of Fig. 7, if one side is fixed from the beginning with stopper plate 13, expanding and brazing can be done in one piece. Although it can be used as a heat exchanger, the displacement of the section 14 occurs, resulting in a loss of space. In addition, in any case, it is necessary to bend a thin flexible sliding plate in between so that the fins in each row of bent parts do not dig into each other and can easily slide, and this installation and removal is quite difficult. It is cumbersome and difficult to automate. Furthermore, since the fin pitch of the inner and outer heat exchangers becomes misaligned, ventilation resistance increases, leading to a decrease in performance.

The present invention aims to improve the problems of the above-mentioned conventional methods. The purpose is to make a cut line by leaving a part of the connecting part at a predetermined position in the longitudinal direction of the fin, to insert the straight part of the hairpin pipe into the hole in the stacked fins, and to expand the pipe. a step of separating the connection portion and dividing the heat exchanger into separate blocks connected by one hairpin pipe; a step of rotating the fins around the straight pipe portion of the hairpin pipe; and a step of rotating the fins. This is achieved by a process of later connecting a bend pipe to a hairpin pipe, and a method of manufacturing a cross-finch tube heat exchanger with a bent part.

According to the method of the present invention, since no bending moment is applied to the pipe, even hard, thin-walled pipes that are prone to buckling can be used, and there is no deformation of the fins, and there is no increase in ventilation resistance due to the pitch being deformed into a tapered shape and becoming narrow. . Since the fins are rotated around the pipe after expansion, the contact pressure between the fins and the pipe is slightly relaxed, but since there are at most two pipes at one bend, and the elastic contact pressure is maintained,
This has less effect on heat transfer than loosening caused by pipe bending. Furthermore, since bending R8 is unnecessary, space can be used effectively. When expanding the pipe, if the pipe 16 serving as the shaft is expanded loosely so that the pipe and fins can easily rotate, processing becomes easier. 16 may not be expanded at all.
After welding was completed, the cutter was applied from the outside of the heat exchanger at part 19 of the fin, and the cutter was moved in the axial direction to cut the heat exchanger, as shown in Figure 8. Using a folding machine or the like as shown in Fig. 8, move the heat exchanger block on the fin 18 side 90 degrees in the direction of the arrow, with the pipe 16 as the axis.
FIG. 11 shows a state in which it has been rotated by an angle to be perpendicular to the heat exchanger on the fin 17 side. Pipe 16 in Figure 11
By welding the bend pipe 20 between the adjacent pipe 22, the heat exchanger having a right-angled bend part can be heated without deteriorating its cooling performance, and the large radius part 8 can be welded.
It can be manufactured without taking.

Fig. 12 shows another example of a single-row pipe heat exchanger, in which the fins on both sides are rotated around both straight pipe parts of a hairpin pipe 15 spanning the fin cut part, and the fins on both sides are rotated. However, as shown in FIG. 12, it is possible to manufacture a heat exchanger with sharp bends that would not be possible by simply bending a single heat exchanger.

FIG. 13 shows an embodiment of a heat exchanger having two rows of pipes.

Since the method of the present invention can automatically perform the process of separating both ends of the fin, only the process of rotating and then welding the bend pipe of the rotating part is added, which overcomes the drawbacks of the conventional method as described above. Great effect can be obtained. Especially when it comes to 2 rows, 2
There is no need to manufacture each piece individually or attach and remove sliding plates, which has the effect of greatly reducing the number of processing steps.Since the inner and outer rows are not separated, there is no difference in ventilation resistance due to misalignment of the fins.

Even a pipe having three or more rows of pipes, which could not be manufactured economically in the past, can be bent in the same way if only one hairpin pipe at the end straddles the cutting line. Of course, the hairpin pipe spanning the separation line may be a welded straight pipe and return pipe.

To explain the following embodiments, FIG. 8 is a front view of one embodiment in which there is one row of pipes before creating a bent part by rotating the fins, and FIG. 9 is a side view of the bend pipe side. be. 15 is a hairpin pipe spanning the cutting line, 16 is a straight pipe portion serving as an axis of fin rotation, 17 and 18 are separate fins, and 3 is a welded bend pipe.
Reference numeral 20 denotes a bend pipe that is later assembled to the pipe 16 serving as the rotating shaft, and is welded after the fins have been rotated. This heat exchanger, as shown in Fig. 10,
The fins 1 with the cut lines 21 left on both end faces are stacked, the hairpin pipe 2 is inserted and expanded, the fins 1 and the hairpin pipe 2 are fixed, and then assembled onto the straight hairpin pipe section 16 that will become the shaft. The bend pipe 3 is assembled and automatically welded except for the bend pipe 20 that is attached.

The virtual line shows the state before bending, and after bending, hairpin pipes 15 and 22 are connected by a bend pipe, and hairpin pipes 23 and 24 are connected by a bend pipe of a special length. This creates a two-row heat exchanger bent at right angles. Furthermore, when manufacturing multiple rows, it is possible to manufacture by adding a dedicated length of bend pipe between each row. Furthermore, the cut line 21 does not necessarily have to be a straight line.

As described above, according to the present invention, by leaving the end faces on both sides of the fin and making the cut lines,
The number of fins before separating them can be halved. Therefore, the pipe is expanded and welded as a single heat exchanger without a bend pipe at the bent part, and then both end faces of the fins at the cut part are cut from the outside to make it easier to bend, and after bending, By welding a small number of remaining bent pipes, it is almost the same as making and bending a single heat exchanger, such as bending heat exchangers that were previously impossible, or bending heat exchangers with three or more rows. Can be manufactured in less processing time. Furthermore, since the long tube portion of the hairpin pipe is rotated after the fin connection portion is separated, no bending moment is applied to the pipe. Therefore, it becomes possible to use hard thin-walled pipes that are prone to buckling.

[Brief explanation of the drawing]

Figure 1 is an external view of a conventional heat exchanger with bent parts, Figure 2 is an external view of a single row heat exchanger without bent parts, and Figure 3 is an external view of a conventional heat exchanger with bent parts. A conceptual diagram showing a method of bending a heat exchanger, Fig. 4 is an equipment layout diagram of a condensing unit with a bent heat exchanger, Fig. 5 is an external view of a two-row heat exchanger without bending parts, FIG. 6 is a top view of a conventional two-row heat exchanger with a bend, FIG. 7 is a top view of a conventional two-row heat exchanger with another bend, and FIG. 8 is a top view of a conventional two-row heat exchanger with a bend. FIG. 9 is a front view in an intermediate step of one embodiment of the invention.
10 is a plan view of a fin used in an embodiment of the present invention; FIG. 11 is a side view of an embodiment of the present invention;
FIG. 12 is a side view of another embodiment of the present invention;
The figure is a side view of another embodiment of the invention. 1...Fin, 2...Hairpin pipe, 3...
Bend pipe, 4...lower mold, 5...upper mold, 6...
Bending die, 7... Heat exchanger, 8... Bending R, 9...
Cabinet, 10... Space, 11... Compressor, 12... Fan, 13... Stop plate,
14... Misaligned portion, 15... Straddling hairpin pipe, 16... Pipe serving as a rotating shaft, 17... Half of the fin, 18... Other half of the fin, 19...
cutting line, 20...bend pipe, 21...cutting line, 22...hairpin pipe, 23...hairpin pipe, 24...hairpin pipe.

Claims (1)

[Scope of Claims] 1. A step of creating a cut line leaving a part of the connecting portion at a predetermined position in the longitudinal direction of the fin, a step of inserting a straight pipe portion of the hairpin pipe into a hole in the stacked fins, and a step of expanding the heat exchanger by separating the connecting portion to separate the heat exchanger into separate blocks connected by a single hairpin pipe; a step of rotating the fins around the straight pipe portion of the hairpin pipe; A method for manufacturing a cross-finch tube heat exchanger having a bent portion, which comprises a step of connecting a bend pipe to a hairpin pipe after rotation of the fins. 2. A method for manufacturing a cross-finch tube heat exchanger having a bent portion as claimed in claim 1, wherein the expansion ratio of the pipe in the portion where the fins are rotated is smaller than that in other portions.