JPS59215266A - Brazing method of heat exchanger assembly formed of aluminum and jig device used therefor - Google Patents

Abstract

PURPOSE:To increase uniformly the temp. in a heat exchanger assembly and to braze satisfactorily the Al heat exchanger assembly by forming the flow passages in said assembly as the force circulating passages for atmosphere gas. CONSTITUTION:A flux is coated on a heat exchanger assembly 1 formed by laminating thin Al sheets 2 and fins 3 and right after drying of the flux the assembly is put into an atmosphere brazing device 12 shut off from the outdoor air. The air in the device 12 is substd. with gaseous N2. The gaseous N2 is circulated by a circulation fan 6 and is heated by a heater 10. The heated atmosphere gas is uniformly distributed by a distributing guide 5 and is forcibly passed through the passages 25 of the heat exchange medium in the assembly 1. The temp. of the whole of the intricate brazed part 24 in the assembly is thus increased. The stable brazing for the Al assembled structure is accomplished by such mechanism.

Description

Detailed Description of the Invention (a) Technical Field The present invention relates to an assembly of aluminum heat exchangers, that is, a set of aluminum heat exchangers in which a large number of aluminum thin plates are laminated in multiple layers through aluminum thin plate fins. The present invention relates to a method for soldering between thin aluminum sheets of a body and to a jig device that can be advantageously used in the method.

(b) Background technology Methods for brazing assembled aluminum structures, including aluminum heat exchangers, include (a) dip brazing performed by immersion in a chloride flux bath; (b)
fJ! (c) Flux brazing by applying fluoride flux and performing in an inert gas; (d)
Brazing carried out in inert gas without flux, (e
) Vacuum brazing, etc.

The present invention includes (b), (c),
It belongs to the method (d) and can be particularly preferably used in the methods (C) and (d).

In other words, the present invention provides a method for brazing assembled aluminum structures in a specific elevated temperature atmosphere.

Aluminum has a low emissivity (approximately 0.1). Therefore, if it is heated in a furnace that mainly uses radiation heat transfer, such as a vacuum furnace, the temperature will rise slowly; As the situation progresses, the deaf person's sexuality is harmed.

Particularly in the case of large-volume aluminum assembled structures,
The internal temperature rise is significantly delayed compared to the surface, making it difficult to cause damage to the wax (-1).

This also applies to slow heating in an atmosphere. Heat transfer in the atmosphere is based on radiation heat transfer and forced or natural convection heat transfer, but in large-scale brazing, even if the external atmosphere surrounding the assembled structure is forced to convect, the There is little air flow inside, and the internal heating is delayed.

This is why most of the brazing of large aluminum structures, especially aluminum heat exchanger assembly structures, relies on dip brazing as described in (a) above.

Dip brazing is required by law, but the reality is that it is difficult to completely remove the flux bath liquid from the structure, especially from the inside, and it takes time and effort. be.

(c) Summary of the Invention The present invention is a method for uniformly and effectively raising the temperature of the entire aluminum heat exchanger assembly structure in an atmospheric gas without using the dip soldering method. It is something.

Generally, a heat exchanger is designed to have a heat transfer area as large as possible compared to its volume, and has a flow path having a large heat transfer area through which a gas or liquid as a heat exchange medium passes. In the present invention, this flow path is used as a passage for atmospheric gas, and the atmosphere scum is forced to circulate through the flow path to uniformly distribute the inside of the aluminum assembly structure by convective heat transfer. In FjI? This is to complete the ``W''.

(d) Examples Hereinafter, the present invention will be explained in more detail with reference to the accompanying drawings.

The heat exchanger assembly l to be brazed consists of a laminated aluminum thin plate 2 (reference numeral 21 in Fig. 2) whose surface is clad with brazing material and an aluminum ttD plate fin 3 (reference numeral 22 and 23 in Fig. 2) processed into a corrugated shape. It was assembled by doing so.

This assembly has a vacuum level of 10-1 after applying flux.
Immediately after drying at a temperature of 180'C, it is placed in an atmosphere waxing device 12 that is isolated from the outside air.

The atmosphere brazing apparatus 12 has a sirocco-type fan 6 for circulating atmospheric gas introduced into the apparatus through an inlet 8 and heated by a heating heater 1o. 7
is a motor for driving the atmospheric gas circulation fan. The device 12 has a door 13 for inserting the assembled body 1, and this door is provided with a thermocouple 11 for controlling the temperature of the atmospheric gas. Reference numeral 9 denotes an exhaust port for exhausting atmospheric gas to the outside of the apparatus, if necessary.

The heat exchanger assembly 1, in which the part indicated by the reference numeral 24 in FIG. , and placed in the device 12, encased in a jacket 26 whose other end has an atmospheric waste distribution guide plate 5. This jacket 26j-1 may be installed in the device 12 in advance, or it may be carried into the device together with the assembly after the assembly 1 is accommodated outside the device.

Therefore, N2 gas is introduced through the inlet port 8 and exhausted through the exhaust port 9, and the air inside the device is replaced with N2 gas (N7 gas is circulated).・Heated by -10.

This heated atmospheric gas is uniformly distributed by the distribution guide IS'5 at the open end of the jacket 26, and is forced to pass through the heat exchange medium flow path 25 of the heat exchanger assembly 1. . This causes all of the complex solder joints 24 within the heat exchanger assembly to heat up. The nitrogen gas passes through the mantle collection guide 4 and is sucked in by the fan 6 and circulated.

In actual operation, the N2 gas brazing atmosphere was controlled by dew point to be -50'0 to -60'O, and brazing was carried out at a temperature of 610'C±3°C for 5 minutes. Temperature control was performed by adjusting the current value of the heater IO using a thermocouple 11. Increase the heating rate to 610°C2
The amount of atmosphere circulation was adjusted within 0 minutes. Due to this -
The results were complete with a stable waxy fillet.

(E) Effects of the Invention As mentioned above, the present invention has the flow path of the heat exchanger assembly made into a forced circulation path for atmospheric gas by brazing, thereby uniformly raising the temperature inside the assembly. It has an excellent effect of making it possible to perform good brazing.

[Brief explanation of the drawing]

Fig. 1 is an explanatory longitudinal cross-sectional view of the device used in the present invention;
The figure is an explanatory cross-sectional view of a portion of an aluminum heat exchanger assembly. Code explanation■-Aluminum heat exchanger assembly? - Aluminum sheet 3 - Aluminum sheet corrugated fins 12 - Furnace arrangement 26 - External tuber holding aluminum heat exchanger assembly

Claims (1)

[Claims] (]) Heating of an aluminum heat exchanger assembly using atmospheric gas is stipulated by the law when the flow path of the heat exchange medium in the assembly is shut off from the outside air when the assembly is inserted. A method for manufacturing an aluminum heat exchanger assembly characterized by a forced circulation passage for heated atmospheric gas circulating within an insulated chamber. (2) Heat brazing of the aluminum heat exchanger assembly using atmospheric gas is performed in an insulated chamber that is isolated from the outside air of the equipment, so that the flow path for the heat exchange medium of the assembly becomes a forced circulation path for the atmospheric gas. A jig device for soldering an aluminum heat exchanger assembly consisting of a jacket structure that supports the above assembly.