JP2854751B2 - Method of manufacturing heat exchanger tube for heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a heat exchanger tube for a heat exchanger such as a room air conditioner.

[0002]

2. Description of the Related Art As a high-performance heat transfer tube having excellent heat transfer characteristics, there is a tube provided with a structure for promoting boiling of a heat medium on the inner surface of the tube. The conventional heat transfer tube provided with this boiling promotion structure,
A plurality of grooves are transferred so as to intersect on a metal plate, and the groove is formed into a cavity (Japanese Patent Application Laid-Open No. 58-18092). After forming parallel grooves, the groove top or groove slope is flattened. Tunnel formed by pressing with a tool (Japanese Unexamined Patent Publication No. 1-11311)
4) There is.

[0003] In order to form a cavity or a tunnel, these heat transfer tubes are manufactured by deforming a bump-like protrusion at the lower portion thereof by pressing a jig from above and bringing adjacent protrusions into close contact with each other. I have.

[0004]

However, in the conventional method of manufacturing a heat transfer tube, a hollow or a tunnel is formed by giving a bump-like deformation by pressing a jig from above, so that in practice, The bulging deformation of the trunk at the lower part is larger than the bump-like overhanging deformation,
Forming a cavity or tunnel is not easy. Therefore, it is difficult to uniformly form a cavity or a tunnel on the inner surface of the tube, and as a result, remarkable improvement in the performance of the heat transfer tube cannot be expected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is possible to form a tunnel portion and an opening uniformly and reliably, and to promote boiling to improve heat transfer characteristics. It is an object of the present invention to provide a method of manufacturing a heat exchanger tube for a heat exchanger that can be performed.

[0006]

SUMMARY OF THE INVENTION A method of manufacturing a heat exchanger tube for a heat exchanger according to the present invention is directed to a heat exchanger for forming a tubular shape while continuously supplying a metal strip and joining the butted ends thereof. In the method for manufacturing a heat transfer tube, a plurality of substantially parallel grooves are formed on a surface of the metal strip plate which is to be the inner surface of the tube, and a cutout is formed in each slope of the groove to form a protrusion, and the opposed protrusions are formed. The portions are tilted in the groove direction and are interconnected discontinuously to form a discontinuous tunnel portion.

[0007]

According to the present invention, in order to form a tunnel, a fin-shaped protrusion is first formed by making a cut in a groove slope, and the protrusion is turned down to connect the opposing protrusions. To form a tunnel. For this reason, since the press molding is performed only on the fin-shaped protrusions, the pressing force required during molding is reduced, and a large tunnel can be obtained.
Further, since the cross-sectional area on the material side cannot be changed in each molding step, the material does not elongate, and it is easy to match the groove phase in each step. And the connection of this protrusion is
Since it is discontinuous along the groove direction, the portion where the protrusion is not connected is an opening. Therefore, the heat transfer surface shape finally obtained is provided with a groove and a tunnel having an opening, and the heat transfer tube for a heat exchanger manufactured according to the present invention has high heat transfer by forced convection heat transfer and boiling heat transfer. It has good evaporative heat transfer characteristics.

[0008]

Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIGS. 1A, 1B and 1C are sectional views showing the method of this embodiment in the order of steps. First, as shown in FIG. 1A, a plurality of mutually parallel grooves 2 are formed in a flat metal strip 1 before being formed into a tubular shape. This groove 2 has a shape having bumps 3 on both slopes.

Next, as shown in FIG. 1 (b), a cut is made in the projection 3 and this is cut open to form a thin fin-shaped projection 4 on both slopes of the groove.

Finally, as shown in FIG. 1 (c), the fin-shaped projections 4 adjacent to each other across the groove bottom are pressed by a jig having a surface having irregularities along the groove direction so that both projections are formed. The part 4 is defeated to connect the two. The surface of this jig has irregularities. Therefore, the protruding portion 4 that has fallen has wavy irregularities as shown in FIG.
Portions that are not connected and become openings 6 are formed alternately and non-connected. Then, a tunnel 7 is formed at a portion where the two protruding portions 4 are connected. In each of the above-described molding steps, tools such as a groove forming jig and a protruding portion pressing jig are designed so that the cross-sectional areas on the material side are the same.

Thus, in this embodiment, FIG.
In the step (3), the adjacent fin-shaped protrusions 4 tilted by the convex surface of the jig are in close contact with each other, and the fin-shaped protrusions 4 tilted by the concave surface of the jig are separated. As a result, a heat transfer surface having the groove 2 and the tunnel 7 having the opening 6 at the bottom of the groove is obtained in the metal strip 1. After the surface processing in this manner, the metal strip 1 is formed into a tubular shape, and the butted portions are welded to produce a high-performance heat exchanger tube for a heat exchanger having excellent heat transfer characteristics.

Next, the result of actually manufacturing the heat transfer tube of this embodiment and testing its characteristics will be described. 9.52 in diameter
mm heat transfer tubes were manufactured using three types of grooved rolls.
Each grooved roll is provided with a groove with a groove bitch P0 = 0.46 mm and a groove lead angle = 20 °. In the first stage of molding, groove depth h1 = 0.3 mm, hump height h2 = 0.2 mm, groove bottom width w = 0.1 m
m (see FIG. 1A). In the second stage, the bump-like projection 3 is opened, and the angle γ = 50 ° and the depth h2-h3 (h3 =
0.1 mm), and fin-shaped protrusions 4 were formed on both sides of the groove [see FIG. 1 (b)]. In the third stage, the groove depth h4 =
A grooved roll having a trapezoidal groove shape of 0.2 mm, a pitch P1 = 0.5 mm in a direction along the groove 2 at a groove bottom, and a height h5 = 0.0.
Press the protruding part 4 using an object with 5 mm unevenness,
As shown in FIG. 2, the bottom of the groove 2 was formed into a wavy surface [see FIG. 1 (c)]. As a result, a tunnel structure having a trapezoidal groove shape and an opening of 0.05 to 0.08 mm below the groove bottom could be provided.

FIG. 3 shows the evaporative heat transfer performance of the heat transfer tube thus manufactured. FIG. 3 is a graph showing the evaporative heat transfer performance, with the horizontal axis representing the refrigerant flow rate and the vertical axis representing the pipe inner film heat transfer coefficient. As shown in FIG. 3, the heat transfer tube of the present embodiment has an evaporation performance of 1.
Excellent heat transfer characteristics of 5 to 1.8 times.

[0015]

According to the present invention, a high-performance heat transfer tube can be manufactured in which a tunnel portion having an opening can be formed uniformly and reliably, and boiling can be promoted to improve heat transfer performance. can do. Thereby, the present invention
It contributes to miniaturization and high performance of the heat exchanger and energy saving.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a method of an embodiment of the present invention in the order of steps.

FIG. 2 is a perspective view showing a heat transfer surface formed by the method of the present embodiment.

FIG. 3 is a graph showing evaporative heat transfer performance.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 metal strip 2 groove 3 bump-like projection 4 fin-like projection 6 opening 7 tunnel

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B21C 37/15 F28F 1/40

Claims (1)

(57) [Claims] 1. A method for manufacturing a heat exchanger tube for a heat exchanger in which a metal strip is formed into a cylindrical shape while continuously supplying the metal strip and a butt end thereof is joined. Forming a plurality of substantially parallel grooves, forming cutouts in each slope of the grooves to form protrusions, and tilting the opposing protrusions in the groove direction to interconnect them discontinuously, A method for manufacturing a heat exchanger tube for a heat exchanger, comprising forming a typical tunnel portion.