JPH0481114B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to heat exchangers with boiling of a medium, such as evaporators and reboilers.

In this specification, front and rear are based on the direction of flow of the medium, and front means forward in the flow direction (arrow A in Figure 1).
(in the direction shown by ), and "back" refers to the opposite side. Furthermore, left and right refers to the front, and the term "aluminum" in this specification includes all aluminum alloys in addition to pure aluminum.

BACKGROUND ART Conventionally, this kind of heat exchanger has been used which is equipped with a flat medium flow pipe made of an extruded aluminum material and in which a plurality of medium flow passages are arranged in parallel. In conventional heat exchangers, the boilability of the medium is increased by mechanically grooving the inner circumferential surface of the medium flow path.

Problems to be Solved by the Invention In the case of the heat exchanger described above, it is difficult to process grooves, and the heat exchange performance is not always satisfactory.

An object of the present invention is to provide a heat exchanger that is easier to manufacture than the conventional ones and has superior heat exchange performance.

Means for Solving the Problems In order to achieve the above object, a heat exchanger according to the present invention includes a pair of aluminum flat plates made of brazing sheets facing each other, and a pair of aluminum flat plates disposed between the two flat plates and brazed to the flat plates. A plurality of flat hollow bodies for media flow each having a rectangular cross section and made of a medium flow passage forming member made of an extruded aluminum material, and a horizontally extending bent portion interposed between the hollow bodies and having bent portions brazed to the flat plates on both sides. The medium flow path forming member is provided with a left and right side wall portion that connects the left and right side edges of the flat plate, and a portion parallel to the flat plate and at the center of the width of the left and right side wall portions. Between the connecting wall and the left and right side walls that connect the parts together, comb tooth-shaped fins are provided on both sides of the connecting wall and the tips are brazed to the flat plate, and the flat plate, the left and right side walls, the connecting wall and A plurality of medium flow passages are formed by comb-like fins, and aluminum powder is brazed to the entire surface of the medium flow passage forming member that faces each medium flow passage to form a porous layer. .

Effect The heat exchanger according to the present invention has two parts facing each other.
A plurality of flat hollow bodies for media circulation each having a rectangular cross section, each consisting of a pair of aluminum flat plates and a medium flow passage forming member made of an extruded aluminum material placed between the flat plates and brazed to the flat plates, and between the hollow bodies. The air flow passage includes a corrugated fin interposed therebetween and extending in the left-right direction and whose bent portions are brazed to the flat plates on both sides, and the medium flow passage forming member connects the left and right edges of the flat plate Connecting left and right side walls, a connecting wall that is parallel to the flat plate and integrally connects the center part of the width of the left and right side walls, and a connecting wall that is provided on both sides of the connecting wall between the left and right side walls and whose tips are brazed to the flat plate. A plurality of medium flow passages are formed by the flat plate, the left and right side walls, the connecting wall and the comb tooth-like fins, and the entire surface of the medium flow passage forming member facing each medium flow passage is made of aluminum. Since the powder is brazed to form a porous layer, the area of the heat transfer surface of the medium flow path is greatly expanded, and
The porous voids between the aluminum powder particles in the porous layer serve as the nucleus for the generation of vapor bubbles in the liquid medium. In other words, when a liquid medium is made to flow in each medium flow path and air is made to flow in the air flow path, the heat transmitted from the air to the corrugated fins and the flat plate is transferred to the comb teeth of the flat plate and the medium flow path forming member. from the fins and connecting walls to the liquid medium.
Then, the pores between the aluminum powder particles in the porous layer become the nucleus for generating vapor bubbles in the medium, and the medium evaporates, and the heat of the air is taken away by the medium, thereby cooling the air.

In addition, since the flat plate is made of brazing sheet and all the components and powder are made of the same aluminum, the aluminum powder is also brazed at the same time as the flat plate, media flow path forming members, corrugated fins, etc. A porous layer can be formed.

Furthermore, the comb-like fins on both sides of the connecting wall also serve as reinforcement due to their shape.

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

The illustrated heat exchanger includes a pair of aluminum flat plates 2 made of brazing sheets facing each other, and a plurality of media flow path forming members 3 made of an extruded aluminum profile placed between both flat plates 2 and brazed to the flat plates 2. An air tank containing a flat hollow body 4 for media circulation with a rectangular cross section and a corrugated fin 5 interposed between the hollow bodies 4 and extending in the left-right direction and having bent portions brazed to the flat plates 2 on both sides. The medium flow path forming member 3 connects the left and right side edges of the flat plate 2 with each other, and the left and right side walls 6 that are parallel to the flat plate 2 and connect the center portions of the widths of the left and right side walls 6. Between the connecting wall 7 and the left and right side walls 6 that are integrally connected, comb tooth-shaped fins 8 are provided on both sides of the connecting wall 7 and have their tips brazed to the flat plate 2. A plurality of medium flow passages 9 are formed by the connecting wall portion 7 and the comb-like fins 8, and aluminum powder 13 is brazed to the entire surface of the medium flow passage forming member 3 that faces each medium flow passage 9 to form a porous structure. A textured layer 14 is formed thereon.

Both front and rear ends of each medium-circulating flat hollow body 4 are connected to a header tank 10 in a communicating manner. The medium is arranged to flow in the direction indicated by arrow A in FIG. 1, ie, from bottom to top. Furthermore, the front and rear ends of the space between adjacent hollow bodies 4 are closed by aluminum closing members 11. Air is made to flow through the air flow passage 12 in the direction shown by arrow B in FIG. 1 by forced or natural ventilation.

The porous layer 14 is formed, for example, as follows. First, aluminum powder 13, brazing filler metal powder, and an organic binder are mixed and a slurry of the mixture is applied to the medium flow path forming member 3 before brazing. It is preferable to use aluminum powder 13 having a diameter of 20 to 500 μm.
This is because if the diameter is less than 20 μm or more than 500 μm, a high-performance boiling heat transfer surface cannot be obtained. Further, it is preferable to use a brazing filler metal powder having a diameter of 20 to 200 μm. This is because it is difficult to industrially produce particles having a diameter of less than 20 μm, and it is difficult to obtain a uniform distribution if the diameter exceeds 200 μm. The mixing ratio of aluminum powder 13 and wax powder is
Although it depends on the powder diameter etc., the weight ratio is usually about 8:1. The organic binder is used to maintain the formation of both powders as a uniform medium over the entire surface facing each medium flow path 9, but it decomposes and evaporates during brazing. When the organic binder is decomposed and evaporated, the aluminum powder 13 is brazed to the surface of the medium flow path forming member 3, and voids are formed between the aluminum powders 13 to form a porous layer. 14 is formed. Since the fulminium powder existing between the tip of the fin 8 and the inner surface of the flat plate 2 is driven out by the bonding force between the two during brazing, the brazing between the tip of the fin 8 and the flat plate 2 is also performed reliably. . porous layer 1
4, the flat plate 2 and the medium flow path forming member 3, the flat plate 2 and the corrugated fin 5, the flat plate 2 and the closing member 11,
It is also formed at the same time as the header tank 10, the flat plate 2, the left and right side walls 6, and the closing member 11 are brazed. Therefore, a slurry made by mixing aluminum powder 13, brazing filler metal powder, and an organic binder should be applied to the required surfaces of the medium flow path forming member 3 before brazing. The porous layer 14 can be easily formed.

In the above embodiment, the medium flow path forming member 3
A porous layer 14 is provided on the entire surface facing each medium flow path 9.
However, a porous layer may also be formed on the surface of the flat plate 2 facing each medium flow path 9.

Effects of the Invention According to the heat exchanger of the present invention, the area of the heat transfer surface of the medium flow path is greatly expanded, and the porous voids between the aluminum powders in the porous layer are In addition to serving as a generation nucleus, the presence of comb-like fins and corrugated fins dramatically improves the heat exchange performance of the heat exchanger, making it possible to make the heat exchanger smaller and lighter.

Since a porous layer can be formed by brazing the aluminum powder at the same time as the flat medium flow path forming member and the corrugated fins, it is possible to manufacture a heat exchanger with a wide boiling heat transfer area. easier to do.

Furthermore, since the comb-like fins on both sides of the connecting wall also serve as reinforcement, there is an advantage that the entire heat exchanger becomes like a gantry.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a partially cutaway perspective view, and FIG. 2 is a partially enlarged plan view of a medium flow path forming member. 1... Heat exchanger, 2... Aluminum flat plate, 3
... Media flow path forming member made of extruded aluminum material, 4 ... Flat hollow body for medium circulation, 5 ... Corrugated fins, 6 ... Left and right side walls, 7 ... Connection wall, 8 ... Comb tooth shape fins, 12...air flow passage, 13...aluminum powder, 14...porous layer.

Claims (1)

[Claims] 1. A plurality of medium flow channels each having a rectangular cross section, each consisting of a pair of aluminum flat plates 2 made of brazing sheets facing each other, and a medium flow path forming member 3 made of an extruded aluminum material disposed between both flat plates 2 and brazed to the flat plates 2. The air flow passage 12 has a corrugated fin 5 interposed between the hollow bodies 4 and extending in the left-right direction and whose bent portions are brazed to the flat plates 2 on both sides. The medium flow path forming member 3 includes left and right side walls 6 that connect the left and right edges of the flat plate 2, and a connecting wall that is parallel to the flat plate 2 and integrally connects the center portions of the width of the left and right side walls 6. part 7 and left and right side wall parts 6
Between the flat plate 2, the left and right side walls 6, the connecting wall 7, and the comb-toothed fins 8, the comb-toothed fins 8 are provided on both sides of the connecting wall 7 and have their tips brazed to the flat plate 2. Multiple medium flow paths 9
is formed, and aluminum powder 1 is applied to the entire surface of the medium flow path forming member 3 that faces each medium flow path 9.
3 is brazed to form a porous layer 14.