JPS59208397A - Manufacture of heat exchanger for water - Google Patents

Abstract

PURPOSE:To constitute a compact heat exchanger at low cost, by filling soft brazing material in the gaps among each end of a number of refrigerant pipes, and among the end of a refrigerant pipe and the end of an outer pipe. CONSTITUTION:The gaps among refrigerant pipes 5 are liquid-tightly bonded to one another by soft brazing material in the brazed part 4a of a bundle 4 of pipes. After the refrigerant pipes 5 are brazed between the brazed part 4a and the end 1a of an outer pipe 1, the end of a bundle of pipes are fitted to the end 1a of an outer pipe liquid-tightly by a sealing agent 6 which is pressedly filled in the cavity part 7 around the brazed part 4a of a bundle of pipes by the pressure being applied by the flare part 8a of a connecting pipe 8, being softened by the heat of a burner. With such an arrangement, a heat exchanger for water of multi-pipe type with refrigerant pipes 5 consisting of a number of capillary pipes being assembled in it can be manufactured. The surface area of a refrigerant pipe 5 per unit length of a heat exchanger, that is a heat exchanging area, can be increased.

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 for liquid-tightly attaching the ends of multiple refrigerant tubes inserted into the outer tube of a multi-tube water heat exchanger to each end of the outer tube.

Conventionally, this type of water heat exchanger, for example,
As shown in the figure, the front end is open and the water supply ports (
a) and a cylindrical outer tube (c) having a drain port (b);
a tube plate (d) fluid-tightly attached to the front end of the outer tube (c);
and a plurality of hairpins which are installed inside the outer tube (c) and are liquid-tightly attached to the tube plate (d) so that both ends (c1), (c1) communicate with the front surface of the tube plate (d). shaped refrigerant pipe (c)... and a lid (i) having a refrigerant inlet part (f) and an outlet part (g) and attached to the front side of the tube plate (d) via a sealing member (h). The refrigerant is supplied from the inlet (f) to the refrigerant pipe (c).
It is known that heat exchange between the refrigerant and the cooling water is carried out by guiding the cooling water from the water supply port (a) through the outer pipe (c) to the drain port (b) while guiding the cooling water through the outlet section (g) through... (Refer to Japanese Utility Model Application Publication No. 10698/1983).

However, in such a multi-tube water heat exchanger, if a small-diameter chiral tube is used as the refrigerant tube and the number of tubes is large (for example, several hundred to several thousand tubes), the heat exchange will be improved. Since the heat exchange area per unit length of the heat exchanger increases, the diameter and length of the outer tube can be made smaller while keeping the heat transfer coefficient of the heat exchanger the same, making it possible to make the heat exchanger more compact. It is possible.

However, in the above conventional system, the refrigerant pipe (c) is connected to the tube plate (
1), provide multiple mounting holes for refrigerant pipes in the ring plate (d), fit the refrigerant pipe ends (c1) into the mounting holes, and attach each end (e1) to the tube plate (d). ), therefore, if refrigerant tubes consisting of multiple capillary tubes are attached to the tube plate (d), the man-hours for machining the refrigerant tube mounting holes and brazing the ends of the refrigerant tubes will increase. However, there is a problem in that the cost is high.

Therefore, the present invention has been made in view of this point, and it is possible to eliminate the gaps between the ends of a large number of refrigerant pipes and the connections between the ends of the refrigerant pipes and the ends of the outer pipes without using the above-mentioned tube sheets. The purpose of this is to manufacture a compact and inexpensive heat exchanger using a simple manufacturing method of filling a soft solder material between the holes.

In order to achieve this object, the manufacturing method of the present invention includes a tube bundle in which a large number of refrigerant tubes are bundled together at each end by brazing, and the brazed portion is attached to the end of the outer tube into a cylindrical outer tube. After inserting the tube bundle into the tube so that it protrudes from the section, a soft solder material is welded between the tube bundle brazing section and the end of the outer tube to form a seal section. The flared part of the connecting pipe, which has a flared part that can be fitted externally at the end of the expanded outer pipe and has a piping connection part to which the refrigerant piping is connected to the end, is attached to the sealing part with the molten soft material of the sealing part. The brazing material is press-fitted around the tube bundle brazing portion and fitted onto the outer tube end, thereby attaching the tube bundle end to the outer tube end in a liquid-tight manner. The connecting tube flare section is fluid-tightly attached to the outer tube end by welding a soft solder material to the outer periphery in a continuous manner with the seal section. As a result, the ends of a large number of refrigerant tubes can be attached to the ends of the outer tube in a liquid-tight manner using the tube bundle brazing section and the sealing section without using a tube plate.

The embodiments of the present invention will now be described in detail based on the drawings.

FIG. 1 shows an embodiment in which the present invention is applied to a multi-tubular water heat exchanger, in which (1) is a cylindrical outer tube with both ends open; ) A water supply pipe (2) that supplies cooling water to the outer tube (1) is on the side of one end (1a), and the other end (1a) is
1a) Drain pipes (3) for discharging cooling water from the outer pipe (1) are connected to each side.

First, the tube bundle (4) through which the refrigerant flows is inserted into the outer tube (1). The tube bundle (4) is made by bundling refrigerant tubes (5) consisting of a large number of capillary tubes at equal pitches and brazing each end (5a) of the refrigerant tubes (5) to each other with soft solder material. It is bound.

The refrigerant pipe (5) is made of a capillary tube made of NEOFLON, a synthetic resin with excellent corrosion resistance.
There is no need to consider corrosion allowance, and the wall thickness can be made extremely thin. Therefore, even though the material is neoflon, which has a lower thermal conductivity than copper, the thermal resistance is reduced and a sufficient heat transfer coefficient can be ensured.

In addition, if the outer diameter of the refrigerant pipe (5) is smaller than 0.1 mm, it is difficult to manufacture and the wall thickness (0.012 m
m) is also thinner, so 0.1 mm or more is appropriate;
On the other hand, if it is larger than 0.2mm, the wall thickness (0.025m
m) is also thicker, so the thermal conductivity (neoflon is 0.
2 kcal/mh (°C)), so it is desirable to select an appropriate value within the range of 0.1 to 0.2 mm.

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

Table 1 Table 2 When inserting the tube bundle (4), the brazed portion (4a
) are made to protrude from each end (a) of the outer tube (1).

Next, as shown in Fig. 2, a small amount of molten soft brazing material is applied with a soldering iron between the brazed part (4a) of the tube bundle (4) and the end (1a) of the outer tube (1). By stacking them one by one, a soft solder material is welded between the two to form a seal portion (6).

After that, the above seal part (
6) is heated to soften the soft solder material of the seal portion (6) to an extent that it does not melt. As a result, the gap between the layers of the soft solder material that was formed in the seal portion (6) when filling the soft solder material is filled with the melted soft solder material, resulting in a uniform seal as shown in Figure 3. Part (6) is obtained. However, the sealing part (6) and the brazed part (4a) of the tube bundle (4) are separated by the refrigerant pipes (5) located on the outer periphery of the tube bundle (4), and there is a gap between them. A cavity (7) is formed therein. In this state, the refrigerant pipe (
A connecting pipe (8) is attached to the outer pipe (1) to connect the outer pipe (1) to the outer pipe (not shown). As shown in FIG. 4, the connecting pipe (8) has a flared part (8a) at one end that widens toward the tip and can be fitted onto the outer pipe end (1a), and has a refrigerant pipe at the other end. It has a pipe connection part (8b) to be connected, and when the flare part (8a) is pressed against the seal part (6) in the state shown in FIG. ), the soft solder material of the sealing part (6), which is melted by heating, is inserted into the hollow part (7) around the tube bundle brazing part (4a).
It is press-fitted and filled. This allows the end of the tube bundle (4) to be attached to the outer tube end (1a) in a liquid-tight manner.

Furthermore, as shown in FIG. 6, soft brazing material is welded to the outer periphery of the flared portion (8a) of the connecting portion (8) by using a soldering iron so as to be continuous with the sealed portion (6). Then, by heating this welded part with a burner to soften the soft solder material in the welded part to an extent that it does not melt, the connecting pipe flare part (8a) is heated to the outer pipe end (1a) with the melted soft solder material. )
Installed in a liquid-tight manner.

Therefore, in the above embodiment, the refrigerant pipes (5) are liquid-tightly bound to each other by the soft brazing material of the brazed portion (4a) of the tube bundle (4), and
) and the end (1a) of the outer tube (1), and after being softened by heating with a burner, the tube bundle brazing portion (4a) is pressed by the flared portion (8a) of the connecting tube (8).
) Sealing part (6) press-filled into the surrounding cavity part (7)
Since the end of the tube bundle (4) is attached to the outer tube end (1a) in a liquid-tight manner, a multi-tube water heat exchanger incorporating refrigerant tubes (5) consisting of multiple capillary tubes is formed. Therefore, the surface area of the refrigerant pipe (5) per unit length of the heat exchanger, that is, the heat exchange area increases. This allows the outer tube (
1) can be made smaller in diameter and length, making it possible to make the heat exchanger more compact.

In addition, unlike conventional manufacturing methods, a tube sheet is not used, and there is no need to create numerous mounting holes for refrigerant pipes in the tube sheet or to braze the ends of the refrigerant pipes to the mounting holes. The heat exchanger can be manufactured with fewer man-hours, thereby reducing the cost of the heat exchanger.

As explained above, according to the manufacturing method of the present invention, after inserting a tube bundle in which a large number of refrigerant tubes are bundled at each end by brazing into the outer tube, the tube bundle is connected to the brazed portion and the outer tube end. A soft brazing material is welded between the parts to form a seal part, and the seal part is heated. The flared part of the connecting pipe having the piping connection part at the end is pressed against the sealing part so that the molten soft solder material of the sealing part is press-fitted around the tube bundle brazing part and fitted to the outer pipe end part. By doing this, the end of the tube bundle is attached to the end of the outer tube in a liquid-tight manner, and then a soft brazing material is applied to the outer periphery of the flared portion of the connecting tube so as to be continuous with the sealing portion and welded, and the flared portion of the connecting tube is attached to the end of the outer tube. Since the heat exchanger is installed in a liquid-tight manner in the outer tube, the use of multiple refrigerant tubes increases the heat exchange area per unit length of the outer tube, making the heat exchanger more compact while keeping the heat transfer coefficient the same. At the same time, by eliminating the need for tube sheets and manufacturing the heat exchanger through a simple process of brazing, it is possible to reduce the cost of the heat exchanger by reducing the number of man-hours, which is an excellent practical effect. It is something.

[Brief explanation of the drawing]

1 to 6 show embodiments according to the present invention;
The figure is an overall sectional view showing the state in which the tube bundle is inserted into the outer tube.
The figure is a partial cross-sectional view showing the state in which the seal part is formed, Figure 3 is an enlarged cross-sectional view taken along the line III--III in Figure 2, and Figures 4 and 5 show the flared part of the connecting tube on the outer tube. A partial cross-sectional view showing the state before and after fitting to the end part, FIG. 6 is a partial cross-sectional view showing the state in which the soft brazing material is welded to the outer periphery of the connecting pipe flare part, and FIG. 7 is an overall perspective view showing the conventional example. It is. (1)...outer tube, (1a)...end, (4)...tube bundle, (4a
)...brazing part, (5)...refrigerant pipe, (6)...sealing part,
(8)...connecting pipe, (8a)...flare part, (8h)...piping connection part.

Claims (1)

[Claims] (1) A tube bundle (4) in which a large number of refrigerant tubes (5) are bound together at each end by brazing is connected to a cylindrical outer tube (1).
) to the end (1a) of the outer tube (1).
After inserting it so that it protrudes from the tube bundle brazing part (4)
A seal portion (6) is formed by soft brazing and welding between the outer tube end portion (1a) and the outer tube end portion. (1a)
A connecting pipe (8
) is pressed against the sealing part (6) so that the molten soft solder material of the sealing part (6) is press-fitted around the tube bundle brazing part (4a) to seal the outer tube end. The end of the tube bundle (4) is attached to the outer tube end (1a) in a fluid-tight manner by fitting into the connecting tube flare portion (1a), and then the soft solder material is sealed as above on the outer periphery of the connecting tube flare portion (8a). Weld the connecting tube flare section (a) to the outer tube end (
1a) A method for manufacturing a water heat exchanger, characterized in that it is attached liquid-tight to a water heat exchanger.