JPS59208395A - Manufacture of heat exchanger for water - Google Patents

Abstract

PURPOSE:To easily manufacture a compact heat exchanger for water, by certainly bundling each end of a number of refrigerant pipes liquid-tightly by a simple method. CONSTITUTION:Refrigerant pipes 7 are liquid-tightly bonded to one another by soft brazing material in the brazing part of a bundle 2 of pipes. The pipes 7 are brazed between the brazing part of a bundle of pipes 7 and the end 1a of an outer pipe, and then the top part 3 of a bundle 2 is fitted to the end part 1a of an outer pipe liquid-tightly by a sealing agent 11 being pressedly filled into the cavity 12 around the brazed part of a bundle by applying pressure to the flare part of a connecting pipe 4b, being softened by the heat of a burner. By this method, a heat exchanger for water of multi-tube type, into which refrigerant pipes 7 consisting of a number of capillary pipes are assembled, can easily be manufactured. The diameter of an outer pipe 1 can be made small, and the length is made short, so that the heat exchanger can be made compact as much as its decreased volume.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a water heat exchanger.
The present invention relates to a method of binding each end of a large number of bundled refrigerant pipes by brazing. In general, water heat exchangers with multiple pipe lengths are constructed by inserting multiple refrigerant pipes into a cylindrical outer pipe and attaching each end of the refrigerant pipes to the outer pipe end in a liquid-tight manner. The cooling water introduced into the outer tube exchanges heat with the refrigerant. By the way, in such a heat exchanger, if a large number (for example, several hundred to several thousand) of small diameter caterpillar tubes (for example, outer diameter 1 mm) are used as refrigerant tubes, the heat flow through the heat exchanger can be improved. Since the outer diameter and length can be made smaller while keeping the heat exchanger constant, it is possible to make the heat exchanger more compact. However, since there are a large number of refrigerant pipes in this product, there is a problem in that the number of manufacturing steps increases significantly if each refrigerant pipe is attached to the end of the outer pipe. In order to solve this problem, for example, as shown in FIG. the end (a1) of a) is inserted into an end sleeve (c) which is fitted tightly into a cylindrical metal can (b);
Silicone oil heated in the hot plate (d) is introduced into the refrigerant pipe end (a1)..., and air is discharged from the inlet (c) of the metal can (b). ) by keeping the interior in a low vacuum state, the refrigerant pipe end (a1) is softened,
As a result, each zero-fold tube end (a1) is deformed into a honeycomb cross section and is liquid-tightly bound to form a tube bundle ([)
A manufacturing method has been proposed to form
However, in the manufacturing method proposed above, it is necessary to insert a large number of refrigerant pipes (a) in advance so as to fill the end sleeve (0), and this insertion work is time-consuming. There was a runner-up problem in that the cross-sectional honeycomb-like deformation of each refrigerant pipe end (a1) could not be made uniform.

Therefore, the present invention has been made in view of these points, and it is possible to easily manufacture a compact water heat exchanger by reliably and liquid-tightly binding each end of a large number of refrigerant pipes using a simple method. The purpose is to make it possible to carry out the following tasks.

In order to achieve this object, the manufacturing method of the present invention sequentially stacks a large number of refrigerant tubes with a soft wax layer closely attached to the surface of the refrigerant tubes to form a bundle of tubes having a substantially circular cross section.
Next, the tube bundle is heated and the outer periphery of the tube bundle is pressurized inward to fill the gaps between the refrigerant tubes with a melted soft wax layer. This allows the refrigerant pipes to be bound together while ensuring the liquid consistency between the refrigerant pipes with the soft wax layer.

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

1 to 5 show an embodiment in which the present invention is applied to a multi-tubular water heat exchanger. In Figure 1, (1)
(2) is an outer tube on a cylinder, (2) is a tube bundle inserted into the outer tube ('1) and each end (3) is brazed to each end '1a) of the outer tube (1); 4a). <4i+'Ht:. ! ．． 74
are the outer tube ends (1a), respectively. (1a) is a connecting pipe which is brazed to the outer pipe end ('la). ('lit
) are connected to a water suction pipe (5) and a drain pipe (6), respectively. Thus, the refrigerant is transferred from the connecting pipe (4a) to the tube bundle (
2) to the connecting pipe (4b), and the cooling water is guided from the water supply pipe (5) into the outer pipe (1) through the drain pipe (6).
), the refrigerant in tube bundle (2) and the outer tube (
1) It is designed to exchange heat with the cooling water.

The refrigerant tubes (7) of the tube bundle (2) are made of Nerofluorocarbon capillary tubes, which are synthetic resins with excellent corrosion resistance, so there is no need to consider corrosion allowance, and the wall thickness can be made extremely thin. It is possible. Therefore, even though the material is made of neofron, which has a lower thermal conductivity than the body, the thermal resistance is reduced and a sufficient heat transmission coefficient can be ensured.

In addition, if the outer diameter of the refrigerant pipe (7) is smaller than 0.1 mm, it is difficult to manufacture and the wall thickness (0.012 l) is smaller than 0.1 mm.
ll111) is also thinner, so a thickness of 0.1 mm or more is appropriate; on the other hand, if it is larger than 0.2 IIm, the wall thickness (0
．． 025+mn) also becomes thicker, so the thermal conductivity (
Neoflon is 0.2 kcal. ．．
Since the thermal resistance due to 'ml+'c (17J) becomes large, it is desirable to select an appropriate value within the range of 1-0.2lim.

Table 1 below shows the use when designing a 1 horsepower evaporator as a reference example. The design conditions at that time are shown in Table 2.

The tube bundle (2) is manufactured by the following procedure. That is, as shown in FIG. 2, first, a plurality of (three in the figure) refrigerant tubes (7) made of resin capillary tubes are arranged in parallel, and then the refrigerant tubes (7)...・
a) Drop molten soft solder material onto the top surface to weld the soft solder layer (8).

Next, as shown in FIG. 3, the refrigerant pipes (7)... and the soft wax layer (ε3) are sequentially stacked on the upper surface of the soft wax layer (8), thereby forming a structure as shown in FIG. 4. A tube bundle (2) having a substantially circular cross section is formed.

After that, as shown in FIG. 5, the tip of the tube bundle (2) (
3a) is provided with a fireproof plate (9) for blocking flame radiation and preventing overheating of the soft wax layer (8), and then the tip (3a) is heated with a burner. At this time, the tube bundle (
2) Be sure to heat to such an extent that the soft wax layer (8) welded to the surface does not melt off. At the moment when the soft wax layer (8) softens and the binding force of the tube bundle (2) loosens, the string is attached to the part of the color bundle end (3) corresponding to the soft wax layer (8) as shown in the figure. (10) and tightening the string 10), the outer periphery of the tube bundle (2) is pressurized almost uniformly inward, thereby softening the soft wax layer (8) into each cold tube bundle (2). Pipe (7
) to fill in the gaps between them.

Thereafter, heating is stopped and the tube bundle (2) is allowed to cool naturally, thereby solidifying the soft wax layer (8) and binding the refrigerant tube ends (7a) in a liquid-tight manner.

Therefore, the tube bundle (2) obtained in this way is formed by sequentially stacking a plurality of refrigerant tubes (7) and the soft wax layer (8). 7) Even though there are a large number of books, they can be easily bundled.

In addition, the soft wax layer (8) is formed by heating the tube bundle tip (3d).
... is softened and the soft wax layer (8) is evenly filled into the gaps between the refrigerant pipes (7) by tightening the string (IO), so that the refrigerant pipes (7) and Even if ... is bent or foreign matter gets mixed in between the refrigerant pipes (7), pinholes will not be formed in the brazed parts, thus ensuring that the ends of the refrigerant pipes (3) are liquid-tight. can be tied to.

Note that the tube bundle (2) manufactured as described above is used as the outer tube (1).
and connect the tube bundle ends (3), (3) to the connecting tube (4a).
, (4b) and the outer tube ends (1a), (1a) will be described below.

First, as shown in FIG. 7, a soldering iron is used to gradually apply molten soft solder material between the brazed part of the tube bundle (2) and the outer tube end (1a) to soften the gap between the two. A seal portion (11) is formed by welding the brazing material.

After that, the above seal part (
11) is heated so that the soft solder material in the seal portion (one) is softened to the extent that it does not melt.

As a result, when filling the soft solder material, the sealing part (11)
The gap between the layers of the soft solder material that had been formed therein is filled with the molten soft solder material, so that a uniform seal portion (11) is obtained as shown in FIG. However, the seal part (11) and the brazed part of the tube bundle (2) are separated by the refrigerant pipes (7) located on the outer periphery of the tube bundle (2), and there is a gap between them. A cavity (12) is formed. In this state, a connecting pipe (4b) connecting the refrigerant pipe and the outer pipe (1) is attached to the outer pipe (1). The connecting pipe (4b)
As shown in Fig. 9, the pipe has a flared part at one end that widens toward the tip at the outer tube end (1a), and has a pipe connection part to which the refrigerant pipe is connected at the other end. By pressing the flared part against the seal part (11) in the state shown in Fig. 9 and fitting it to the outer tube end part (1a) as shown in Fig. 10, the seal is melted by heating. The soft solder material of the section (11) is press-fitted into the cavity section (12) around the tube bundle brazing section. As a result, the distal end (3) of the tube bundle (2)
) is attached in a liquid-tight manner to the outer tube end (la).

Furthermore, as shown in FIG. 11, a soft solder material is welded to the outer periphery of the flared portion of the connecting tube (4b) so as to be continuous with the sealing portion (11) using a soldering iron. Then, by heating this welded part with a burner so that the soft solder material in the welded part is softened to the extent that it does not melt, the flared part of the connecting tube (4b) is attached to the outer tube end ( 1a)
Installed in a liquid-tight manner.

Therefore, the refrigerant pipes (7) are liquid-tightly bound together by the soft brazing material of the brazed portion of the pipe bundle (2), and
After being welded between the tube bundle brazing part and the outer tube end (1a), the connecting tube (4b) is softened by heating with a burner.
) The tip (3) of the tube bundle (2) is connected to the outer tube end (1a) by the sealing portion (11) which is press-fitted into the cavity (12) around the tube bundle brazing portion by the pressure of the flare portion of the tube bundle (2).
Since it can be installed in a liquid-tight manner, it is possible to manufacture a multi-tube water heat exchanger that incorporates refrigerant pipes (7) consisting of multiple capillary pipes, and the direct line of the outer pipe (1) can be made smaller. Moreover, the length can be shortened, and the heat exchanger can be made more compact.

As explained above, according to the manufacturing method of the present invention, a large number of refrigerant tubes are stacked up in order through a soft wax layer welded to the surface of the refrigerant tubes to form a tube bundle having a substantially circular cross section,
Next, by heating the tube bundle and inwardly pressurizing the outer periphery of the tube bundle, a melted soft wax layer is filled into the gaps between each refrigerant tube. Since the ends of the refrigerant pipes can be reliably tied together in a liquid-tight manner, a compact water heat exchanger can be manufactured easily.

[Brief explanation of the drawing]

1 to 5 show embodiments according to the present invention;
The figure is a sectional view showing a multi-tube water heat exchanger, Figures 2 to 5 are process explanatory diagrams showing the manufacturing procedure of the tube bundle, Figure 6 is a sectional view showing a conventional example, and Figure 7 is a seal section. 3 is an enlarged sectional view taken along the line ■1-■ in FIG. 7, and FIGS. 9 and 10 are views before and after fitting the flare part of the connecting pipe to the end of the outer pipe, respectively. FIG. 11 is a partial sectional view showing a state in which a soft brazing material is welded to the outer periphery of the connecting tube flare portion. (2)...Pipe bundle, (7)...Refrigerant tube, (8)...
Soft wax layer.

Claims (1)

[Claims] (1) A tube bundle (2) in which a large number of refrigerant tubes (7) are stacked one after another with a soft wax layer (0) welded to the surface of the refrigerant color (7) and bundled into a substantially circular cross section. form, then
The tube bundle (2) is heated and the outer periphery of the tube bundle (2) is pressurized inward to fill the gap between each refrigerant tube (7) with a melted soft wax layer (8). A method for manufacturing a water heat exchanger.