JPH01249261A - Manufacture of aluminum made lamination type heat exchanger - Google Patents

Abstract

PURPOSE:To stabilize the brazing property in the inner part of a lamination type heat exchanger and to improve the pressure resistant strength by providing a hole at the one side or both sides of the rib of the part where the mutual inner ribs of a tube sheet are brought into contact and brazing it by heating under vacuum. CONSTITUTION:The joining of an inner rib 3 is improved by flowing it into the inner part through a hole 4 by providing the hole at one side or both sides of the contact part of the mutual inner ribs 3 of tube sheets 2, 2'. On the brazing property of the rib joining part, the evaporation of Mg from a brazing filler metal is promoted at the tube sheet inner part as well by providing the hole at the rib joining part, not only the destruction of an oxide film is facilitated but also the inner part exhausting performance in brazing heating is improved and the inner part brazing property is improved.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for manufacturing an aluminum laminated heat exchanger, and in particular to a method for manufacturing a laminated aluminum heat exchanger, particularly vacuum brazing or non-corrosive flux brazing of a doron cup type evaporator. Brazing is improved in properties.

[Conventional technology]

A stacked heat exchanger, such as a stacked evaporator, has a third
As shown in the figure, brazing sheet (JIS 300
Tube sheets (2), (2'
), stack them one by one in the opposite direction, and place an outer fin (1) made of JIS/1 or JIS 3003 bare material between the tube sheets, and then install the In the situation where there is a gap, it is cleaned with an organic solvent, then assembled into a jig, preheated and dried, and then vacuum brazed by heating about 5 volumes to 600°C in a vacuum of about tO-5 Torr. The brazing sheets used in laminated evaporators have a thickness of about 0.5 to 0.6 m, and the fins have a thickness of about 0.1 m.

On the other hand, non-corrosive flux brazing methods using fluoride-based fluxes are now being used for brazing aluminum parts, and compared to conventional brazing methods that use chloride-based fluxes, pretreatment is required using solvents. Since degreasing is sufficient and there is no need for post-treatment, its cost advantages have attracted attention, and it has been adopted for brazing aluminum radiators and condensers. The non-corrosive flux brazing process involves applying a flux liquid containing about 5% non-corrosive flux to the heat exchanger by spraying, etc.
After drying at a temperature of about ℃, the dew point is -40℃ or less and the oxygen concentration is 1.
The process is carried out by heating to 600° C. in a gas of up to 1,000 pl). However, when applying the above-mentioned hollow structure heat exchanger, a method for applying non-corrosive flux has not been established and has not been put to practical use.

[Problem to be solved by the invention]

When vacuum brazing laminated heat exchangers such as Dron cup type evaporators, the joints between the ribs inside the tube sheet and the inside of the flanges are affected by changes in conditions such as the degree of vacuum and temperature of the furnace, and the brazing properties fluctuate. There are cases where In such cases, problems arise such as a decrease in pressure resistance and a decrease in fatigue life (due to changes in internal pressure).

To create a laminated heat exchanger using non-corrosive flux brazing, flux is applied to each outer fin and tube sheet, and after drying, the core is assembled, or after the core is assembled, the inside of the core is also coated. It is necessary to apply the flux by dipping so that it spreads, and in both cases, not only does the amount of flux increase, but especially in cases where the refrigerant circuit is complex,
The brazing properties inevitably deteriorate due to incomplete application or insufficient drying.

(Means for Solving the Problems) In view of this, as a result of various studies, the present invention stabilizes the properties of brazing inside a laminated heat exchanger in both vacuum brazing and non-corrosive flux brazing, We have developed a manufacturing method for aluminum laminated heat exchangers that can improve pressure resistance.

That is, one of the present inventions is to press-form a brazing sheet to form a tube sheet with inner ribs, laminate the sheets, arrange outer fins between the tube sheets, assemble the core, and join by brazing. In manufacturing a laminated heat exchanger, holes are provided on one or both sides of the ribs where the inner ribs of the tube sheet come into contact with each other, and heat brazing is performed in a vacuum.

Another aspect of the present invention is to press-form a brazing sheet to form a tube sheet with inner ribs, and to laminate the sheets and arrange outer fins between the tube sheets.
In the manufacture of aluminum laminated heat exchangers in which cores are assembled and joined by brazing, holes are provided on one or both sides of the ribs where the inner ribs of the tube sheet come into contact with each other.
Apply non-corrosive flux from the invasive side of the core assembly and dry.
It is characterized by heat brazing in an inert gas.

[For production]

As shown in FIGS. 1A and 2B, the present invention provides an inner rib (3) made of a brazing sheet,
Tube sheet (2) forming tank (5), (2
A hole (4) is provided on one or both sides of the part where the inner ribs (3) of the inner ribs (3) contact each other, and vacuum brazing or non-corrosive flux brazing is performed. The amount used for joining 1) is small, and other than the amount used for joining tube sheets (2) and (2°), it only accumulates in the recesses that formed the inner ribs (3), but the tube sheet (2), (2°) inner rib (3) hole (4) on one or both sides of the contact area
), it flows into the interior through the hole (4) and improves the bondability of the inner rib (3).

In addition, the performance of conventional brazing of rib joints in surface contact is slightly affected by clearance, etc., but by providing holes in the rib joints, the evaporation of M9 from the brazing metal is promoted inside the tube sheet, and the oxide film is formed. Not only is it easier to destroy, but brazing also improves the internal exhaust performance during heating, and internal brazing improves the properties. Furthermore, after assembling the core, by simply applying non-corrosive flux as a liquid spray from the outside of the core, a small amount of flux will penetrate into the inside of the rib through the holes formed in the rib, making it possible to perform non-corrosive flux brazing. .

The hole provided in the inner rib can be made larger depending on the width of the rib. However, if the width exceeds the rib width, the inside and outside are sometimes no longer separated by the brazing material, making it impossible to form a refrigerant circuit. In other words, a hole will be left in the rib. The shape of the hole is circular, oval,
Any shape such as square, rectangle etc. can be applied. For example, in the case of a circle, a diameter of 0.5 m or more is desirable. This is because if the diameter of the hole is less than 0.5mm, the inflow of the brazing material and penetration of the flux will be hindered, and no improvement in brazing properties will be observed.

〔Example〕

Example (1) JIS 3003 material is used as the core material, and JIS 4 material is used on both sides.
The laminated evaporator shown in Fig. 3 was constructed using an inner ribbed tube sheet made of a 0.6 m thick brazing sheet clad with 15% 004 brazing material and a 0.1 # thick outer fin made of JIS 3003 material. The vacuum brazing of was tested and the properties of the brazing were evaluated. The results are shown in Table 1.

In other words, when the tube sheets (2) and (2') are stacked as shown in Figures 1 (a) and (b) and 2, the inner ribs (3) are placed on one or both sides of the tube sheets where they are in contact with each other. Holes (4) with a diameter of 0.3 to 2 were provided, and these were laminated together with the outer fin (1). After degreasing this with Triclean, dry it, tighten it with a jig, and tighten it with 5X
Vacuum brazing was performed by heating at 600°C for 5 minutes in a vacuum of 10-5 Torr. Brazing performance was evaluated by the joint length of the ribs.

As is clear from Table 1, all of the methods Nα1 to Nα6 of the present invention have longer joint lengths at rib joints and superior brazing properties compared to the conventional method Nα8 in which no rib holes are provided. I know that there is.

On the other hand, in comparison method Nα7, in which the diameter of the hole provided in the rib is as small as 0.3 m, it can be seen that no improvement in brazing properties is observed.

Example (2) JIS 3003 material is used as the core material, and JIS 4 material is used on both sides.
Using an inner ribbed tube sheet made of a 0.6M thick brazing sheet clad with 15% 045 brazing material and a 0.1# thick outer fin made of JIS 3003 material, a laminated evaporator as shown in Fig. 3 was constructed. Non-corrosive brazes were tested and the brazes evaluated for their properties. The results are shown in Table 2.

That is, when the tubesheets are stacked in the same manner as in Example (1), holes of 0.3 to 2M are provided on one or both sides of the tubesheet where the inner ribs come into contact with each other, and these are stacked to form the tubesheet. , which were laminated together with the outer fin. After degreasing this with Triclean,
Tighten with a jig and use non-corrosive flux (KAj!F4
Toni:+5% aqueous solution of eutectic composition of AIP6) was spray applied, dried, heated in Oki Gas at 600° C. for 5 minutes, and non-corrosive flux brazing was performed. The brazing quality was evaluated based on the joining length of the ribs as in Example (1).

Table 2 As is clear from Table 2, ribs cannot be joined using the conventional method Nα16 in which no holes are provided in the ribs, but with the methods Nα9 to 14 of the present invention, the joining length of the rib joints is It can be seen that brazing is superior for a long time.

〔Effect of the invention〕

As described above, according to the present invention, in the method for manufacturing an aluminum laminated heat exchanger by brazing, the inner brazing of the tube sheet has improved properties and is stabilized, and the manufacturing method using vacuum brazing, which has been put into practical use in the past, can be improved. It has remarkable industrial effects, such as improving the pressure resistance of the core, and making it easier to apply flux and make it possible to manufacture non-corrosive flux brazing, which has not been put into practical use in the past. It is something.

[Brief explanation of the drawing]

Figures 1 (a) and (b) show the main parts of the core of a laminated evaporator manufactured by the manufacturing method of the present invention, in which (a) is a side sectional view, (b) is a plan view, and Figure 2 is the same. FIG. 3 is a perspective view showing essential parts of the core, and a side view showing an example of a stacked evaporator. 1.7 Outer fin 2.2', tube sheet 3, inner rib 4, hole 5, tank Figure 1 (A) (B)

Claims (2)

[Claims] (1) Aluminum laminated heat exchanger in which a brazing sheet is press-molded to form a tube sheet with inner ribs, these are laminated, outer fins are arranged between the tube sheets, a core is assembled, and they are joined by brazing. 1. A method for manufacturing an aluminum laminated heat exchanger, characterized in that holes are provided on one or both sides of the ribs where the inner ribs of the tube sheet come into contact with each other, and then heated and brazed in a vacuum. (2) Aluminum laminated heat exchanger in which a brazing sheet is press-molded to form a tube sheet with inner ribs, this is laminated, outer fins are arranged between the tube sheets, a core is assembled, and they are joined by brazing. In manufacturing, holes are made on one or both sides of the ribs where the inner ribs of the tube sheet come into contact with each other, and after the core is assembled, non-corrosive flux is applied from the outside, dried, and then heated and brazed in an inert gas. A manufacturing method for aluminum laminated heat exchangers.