JPH0284251A - Heat exchanger tube and its manufacture - Google Patents

Abstract

PURPOSE:To supply the heat exchanger tube whose wall thickness is thin and whose height is low and to improve the pressure resisting performance and the heat transfer performance by forming plural pieces of passages by depositing plural pieces of prescribed thin tubes at a prescribed interval between two pieces of metallic plates which are placed in parallel to each other. CONSTITUTION:The heat exchanger tube is constituted by laminating plural pieces of thin tubes 3 made of a metal at a prescribed interval between two pieces of long-sized plate materials 1a, 1b made of a metal which are placed in parallel to each other in the upper and the lower parts and depositing the plate materials 1a, 1b and the thin tubes 3. Therefore, height of the heat exchanger tube can also be made low, and the heat exchanger tube whose height is <=3mm can be manufactured easily. Simultaneously, a ventilation resistance can also be decreased, and also, since the wall of the thin tube 3 is deposited to the plate materials 1a, 1b and plural passages 6 are formed, the pressure resisting performance and the heat transfer performance can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to heat exchanger tubes used in heat exchangers for air conditioners, refrigeration equipment, automobile equipment, etc., and a method for manufacturing the same.

BACKGROUND OF THE INVENTION In recent years, as heat transfer tubes of this type, polarized tubes used in automobile radiators and serpentine tights used in automobile air conditioners are well known.

A conventional heat exchanger using flat tubes of this kind uses a flat tube 51 as shown in FIGS. 12 and 13, and fins 52 are joined between the flat tubes by bending them, and It constitutes a heat exchanger.

In addition, in the case of the serpentine type, the external shape as a heat exchanger is almost the same as shown in Figure 12, but as a heat exchanger tube, a girder is installed inside to improve pressure resistance and heat transfer characteristics, as shown in Figure 14. It was common to use a plurality of extruded aluminum tubes 53.

Problem to be Solved by the Invention However, when the heat exchanger using the flat tube 51 described above is used as a condenser using a refrigerant, the pressure inside the tube is 16
~2o g/ca, the vicinity of the center expands, causing problems in terms of pressure resistance, such as peeling off of the joints with the fins 62 or, in severe cases, cracks in the heat exchanger tubes.

In addition, in the case of the serpentine type, since it is manufactured by extruding aluminum, if the thickness of the slack tube 63 is made thin or the height h is made too low in order to improve heat conduction, it may break during extrusion. Therefore, a certain degree of wall thickness and height h are required (especially for this type of heat exchanger tube,
The height below mtn was higher than or only in production). This has the problem that the thermal resistance of the tube increases and the heat conductivity deteriorates, and the problem that ventilation resistance cannot be reduced.

In order to solve such problems, the present invention aims to provide a heat exchanger tube with a simple structure and excellent pressure resistance and heat transfer properties, and a method for manufacturing the same.

Means for Solving the Problems In order to achieve this object, the heat exchanger tube of the present invention and its manufacturing method are provided such that a plurality of metal tubes are placed between two elongated metal plates placed vertically and parallel to each other. sexual tubules are placed at regular intervals,
The plate material and the thin tube are welded together to form a plurality of channels between the thin tubes, and the height of the plate material is set to 3 mm or less.

The manufacturing method involves inserting a plurality of thin tubes at regular intervals between two long metal plates placed vertically and parallel to each other, which are extruded and then bow-stretched to a predetermined thickness and size. A solder foil for welding is inserted between the plate material and the thin tube, and after lamination, the plate material and one thin tube are heated in a heating furnace and pressed or rolled in the vertical direction, and the solder foil is By melting and welding the plate material and the thin tubes, multiple flow channels are formed.

Function: With this configuration, the plate material and the tube are welded together to form a thin, strong, uniform body with good heat conduction.
In addition, this method makes it possible to supply thin-walled and low-height heat transfer tubes, which were difficult to manufacture using conventional manufacturing methods using only extrusion and pultrusion, and also allows for a larger number of flow channels. As a result, products with improved pressure resistance and heat transfer performance and reduced ventilation resistance can be manufactured.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 shows the constituent materials of a heat exchanger tube in a first embodiment of the present invention. In FIG. 1, two long plates 1a made of a metallic material such as aluminum are placed vertically and parallel to each other.

1b, wax foil 2a and rectangular thin tubes 3 made of a metallic material such as aluminum, which have been extruded and stretched to a predetermined size, are placed on the plate 1a at regular intervals;
Further, the wax foil 2b and the plate material 1b are laminated in this order. Then the second
As shown in the figure, plate materials 1a stacked in the heating furnace 4,
1b and tubule 2a.

Pass 2b. Inside the heating furnace 4 are wax foils 2a and 2b.
Heating is controlled to be higher than the melting temperature of , and by roll 5,
Since the plates are pressurized and rolled in the vertical direction, the plate materials 1a and 1b and the thin tubes 3 are completely welded together, forming flow paths 6 within and between the plurality of thin tubes as shown in FIG. As described above, the cross-sectional shape of FIG. 3 is formed by extruding and then stretching the thin tube 3 instead of integrally extruding or pultruding, so that the wall thickness of the thin tube can be made thin and uniform.
Moreover, since the diameter of the thin tube can be made small, the height a of the heat exchanger tube can be reduced. Further, since the thin tube 3 is fixed by brazing, the plurality of flow channels 6 are completely partitioned, and the pressure resistance is considerably improved compared to a normal flat tube.

The heat transfer performance is also determined by the thermal conductivity K (Kcal/m'
h −K ) becomes larger, which improves the performance.

Generally, the heat transfer coefficient is expressed by the following formula.

Here, Fsa: Air side surface area (door) FSR: Refrigerant side surface area (door) αa: Air side heat transfer coefficient (Kcal/silence, K) φ:
Fin efficiency CtR: Refrigerant side heat transfer coefficient (Kc a 1 /771'
h −K ) γrn: Thermal resistance of the tube (m' h − /
Kcal) As is clear from the above equation (1), the ratio of the air side surface area Fsa to the refrigerant side surface area FSR is Fsa/F
If sR is made smaller, the heat transfer coefficient will be increased.

Compared to the conventional flat tube, the tube has a thin tube of 3 mm and the same external area (F
sA), the pipe inner area (FRA) becomes larger, so the pipe outer and outer area ratio FSA/FRA becomes /fy smaller, and the heat transfer coefficient K
becomes larger.

Also, since the wall thickness can be made thinner than that of a serpentine quive, the thermal resistance γ is higher. becomes smaller. Furthermore, since the plurality of flow paths 6 are formed by the thin tubes 3, the equivalent tube diameter becomes smaller.
αR increases. As a result of the above, the coefficient of heat transmission is further increased, which has the effect of improving heat conductivity.

Next, as a second example, a fourth example is shown for the case where the thin tube is a circular tube.
The explanation will be based on FIG. In the first embodiment, the thin tube 3 forms a flow path 6 with respect to the rectangular tube, which is surrounded by the inner diameter of the circular tube 7, the space between the circular tubes 7, and the upper and lower plate members 1a and 1b. The effects of pressure resistance and thermal conductivity are the same as in the first embodiment, but when the circular tubes 7 are formed to protrude approximately radially from both ends of the plate materials 1a and 1b, the longitudinal direction of the joined heat exchanger tubes 8 is Both ends are rounded by the circular tube 7. Therefore, by improving the flow of air 9 flowing outside the heat exchanger tubes 8, ventilation resistance can be reduced and α8 can be increased.
The heat transmission coefficient K can be further improved.

A third embodiment of the heat exchanger tube 12, which is a combination of a rectangular tube 1o and a circular tube 11, will be described in FIGS. 6 and 7. The effect is the same as that of the second embodiment, but since the thin tubes in the heat transfer tubes 12 are rectangular tubes 1o, positioning at the time of stacking is easier and it is easier to fix than circular tubes.

A fourth embodiment will be described with reference to FIGS. 8 to 11.

8 and 9 show a thin tube 13 having a rectangular outer shape with numerous unevenness 14 provided inside thereof to increase the internal surface area and improve heat conduction. Figures 1 and 11 have a rectangular outer shape and numerous irregularities inside, and the inner surfaces of the thin tubes and plates 15a and 15b (between the thin tubes in the portion corresponding to the inner side of the tubes) are shown in Figures 1 and 11. A plurality of projections and recesses 16 are provided in the portions (where the thin tubes do not join). The unevenness 14 and 16 can be easily manufactured because they are formed in advance at the time of extrusion molding of the thin tube and the plate material, and the effect is that the tube inside area FsR can be increased and the tube outside area ratio S
Fa/SFR becomes small, and the heat transfer coefficient K can be further improved.

As described above, in the heat exchanger tube of the present invention, thin tubes formed by extrusion molding and stretching are stacked and welded between two plate materials, so the height of the heat exchanger tube can be reduced, and the height is 3.
It is possible to easily manufacture heat exchanger tubes with a diameter of 1 mm or less. At the same time, ventilation resistance can be reduced, and the walls of the thin tubes can be welded to the plate material to form multiple channels, thereby improving pressure resistance and heat transfer performance.

In this example, the number of channels is seven, but it is possible to increase the number of channels and improve performance by changing the diameter and spacing of the thin tubes.

Further, although rectangular tubes and circular tubes are illustrated as thin tubes in this embodiment, it is not to be said that similar effects can be obtained with hexagonal tubes or more.

Effects of the Invention As is clear from the above description of the embodiments, according to the heat exchanger tube and the manufacturing method thereof of the present invention, a predetermined wall thickness is formed between two metal plates placed parallel to each other.

Multiple thin tubes formed to a certain size are placed at regular intervals and welded together to form multiple flow channels, which is difficult to achieve with conventional manufacturing methods that involve only extrusion and pultrusion. By making it possible to supply heat transfer tubes with thin walls and low heights, and by increasing the number of flow channels, we can improve pressure resistance and heat transfer performance, and reduce ventilation resistance, which has great practical effects. can get.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main structure of a heat exchanger tube showing an embodiment of the present invention. 1a, 1b...Plate material, 2a, 2b...
Wax foil, 3.7, 11.10.13... Thin tube,
4...Heating furnace, 5...Roller, 6...-
・Flow path.

Claims (7)

[Claims] (1) A plurality of metal thin tubes are provided at regular intervals between two long metal plates placed vertically and parallel to each other, and the plates and the thin tubes are welded to form a thin tube. A plurality of channels are formed between the thin tubes, and the height of the plate material is set to 3 m.
Heat exchanger tube with a diameter of less than m. (2) The heat exchanger tube according to claim 1, wherein the plurality of thin tubes are polygonal tubes. (3) Claim 1 in which the plurality of thin tubes are circular tubes
Heat exchanger tube as described in section. (4) The heat exchanger tube according to claim 1, wherein the plurality of thin tubes are a combination of circular tubes and polygonal tubes. (5) Multiple thin tubes, extruded and stretched to a predetermined thickness and size, are arranged at regular intervals between two long metal plates placed vertically and parallel to each other. Then, a solder foil for welding is inserted between the plate material and the thin tube, and after lamination, the plate material and the thin tube are heated in a heating furnace and pressurized or rolled from above and below to melt the wax foil. A method for manufacturing heat transfer tubes by welding plate materials and thin tubes. (6) The heat exchanger tube according to claim 1, wherein innumerable irregularities are formed inside the plurality of thin tubes. (7) The heat exchanger tube according to claim 6, wherein innumerable irregularities are formed on the surface of the plate material between the thin tubes and not in contact with the thin tubes.