JP2009079836A - Heat transfer tube and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat transfer tube having the tin thickness and having the constant height, and its manufacturing method. <P>SOLUTION: This heat transfer tube 1 is composed of a clad tube 4 having an inner layer 2 and an outer layer 3. A part of the outer layer 3 is formed as a fin 5 protruding in the radial direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat transfer tube having fins with a small thickness and a constant height, and a method for manufacturing the same.

  There is a heat transfer tube having fins extending spirally around the tube. As such a heat transfer tube, Patent Document 1 describes a heat transfer tube in which fins are formed by performing a raising process that deforms without cutting the outer surface of the tube with a cutting tool. Raising is a type of cutting with a cutting tool. Due to the cutting process, very thin fins can be formed. If the fins are thinned, the heat transfer area is increased and the heat transfer performance is improved and the weight of the heat transfer tube is reduced.

Japanese Patent Publication No.55-10840 Japanese Examined Patent Publication No. 7-107479

  However, if the fins are made thinner to further improve the heat transfer performance, the roundness of the cross section of the raw tube (heat transfer tube before forming the fin) and the concentricity of the rotation of the raw tube and the bite are affected. Becomes larger and the cutting depth of the cutting tool is not constant. For this reason, the fin height is not constant, and the heat transfer performance of the heat transfer tubes varies.

  Accordingly, an object of the present invention is to solve the above problems and provide a heat transfer tube having fins with a small thickness and a constant height, and a method for manufacturing the heat transfer tube.

  In order to achieve the above object, the heat transfer tube of the present invention comprises a clad tube having an inner layer and an outer layer, and a part of the outer layer is a fin protruding in the radial direction.

  The fin may extend by spirally winding the outer periphery of the clad tube.

  You may have a helical groove | channel on the inner surface of the said inner layer.

  Further, the heat transfer tube manufacturing method of the present invention forms a cut in the outer layer from the outside of the clad tube having an inner layer and an outer layer, and forms a fin protruding in the radial direction by raising a part of the outer layer from the cut To do.

  The present invention exhibits the following excellent effects.

  (1) The fin is thin.

  (2) The height of the fin is constant.

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

  As shown in FIG. 1, a heat transfer tube 1 according to the present invention includes a clad tube 4 having an inner layer 2 and an outer layer 3, and a part of the outer layer 3 is a fin 5 raised in the radial direction. is there.

  In the present embodiment, the fin 5 is formed to rise linearly from the outer peripheral surface of the clad tube 4, that is, radially outward. Since FIG. 1 is a side sectional view of the heat transfer tube 1 as viewed from the side, fins 5 standing upright appear at the upper and lower portions of the heat transfer tube 1 respectively. A single line of fins 5 is formed by spirally winding the outer periphery of the clad tube at a predetermined pitch.

  Examples of the material for the inner layer 2 include copper and aluminum. Examples of the material for the outer layer 3 include copper, aluminum, and stainless steel. In this embodiment, the clad tube 4 consists of only two layers, an inner layer 2 and an outer layer 3.

  The inner layer 2 and the outer layer 3 are in close contact with each other, but are not integrated by bonding or the like, and can be mechanically peeled off by a raising tool described later.

  As a specific example, the thickness of the fin 5 is 0.1 mm, the height of the fin 5 (the distance from the outer peripheral surface of the inner layer 2 to the tip of the fin 5) is 1.4 mm, and the outer diameter (upper part) of the fin 5 The outer diameter of the fin 5 from the tip of the fin 5 to the tip of the lower fin 5 is 9.42 mm and the helical pitch of the fin 5 is 1.99 mm. The thickness of the outer layer 3 is 0.1 mm.

  The heat transfer tube 1 has a spiral groove 6 on the inner surface of the inner layer 2. The inner surface grooves 6 are known, and a plurality of inner surface grooves 6 are formed side by side at a predetermined circumferential angle pitch.

  Next, a method for manufacturing the heat transfer tube of FIG. 1 will be described with reference to FIG.

  First, a clad tube 4 having an inner layer 2 and an outer layer 3 is formed. A slit 8 is created in the outer layer 3 by applying a cutter blade 7 to the clad tube 4 from the outside. While the cutter blade 7 and the clad tube 4 are rotated relative to each other, the clad tube 4 is run in the longitudinal direction to form a cut 8 in a spiral shape. The pitch of the cuts 8 is the same as the spiral pitch of the fins 5 to be formed.

  Next, at a position downstream of the cutter blade 7, the fin 5 is formed by raising (raising) a part of the outer layer 3 from the cut 8 by the raising tool 9 and raising it in the radial direction. The raising tool 9 is arranged with a gap 10 of a predetermined distance with respect to the outer peripheral surface of the clad tube 4. The distance of the gap 10 is preferably 0.1 mm or more and less than 1 mm.

  At this time, the pressing member 11 is raised from the downstream side of the raising tool 9 and opposed to the tool 9. The pressing member 11 is a member having an outer layer pressing surface for pressing a part of the outer layer 3 (a portion left by raising) and a fin pressing surface perpendicular to the outer layer pressing surface.

  Here, as shown in FIG. 3, the raising tool 9 has a cutting edge inclined with respect to the normal line of the clad tube 4, and the outer layer 3 is raised by this cutting edge. The raising tool 9 is made of the same material (steel, ceramic, cemented carbide, etc.) as other tools used for cutting. In FIG. 3, the inner surface groove 6 is omitted from the cladding tube 4.

  At the start of the raising process, the gap between the cutting edge of the raising tool 9 and the outer peripheral surface of the cladding tube 4 is eliminated so that the raising tool 9 contacts the outer layer 3. When the outer layer 3 is raised and placed on the cutting edge of the tool 9 and begins to rise from the outer peripheral surface of the cladding tube 4, the cutting edge of the raising tool 9 is separated from the outer peripheral surface of the cladding tube 4, and the outer layer 3 is continuously raised in this state. . The reason why the raising tool 9 is separated from the outer peripheral surface of the clad tube 4 is that the cross section of the clad tube 4 is not a perfect circle. This is because the inner layer 2 may be damaged.

  Further, if the erection process is started from the end of the clad tube 4, the outer layer 3 may be largely peeled off. Therefore, the portion where the cutter blade 7 starts making the cut 8 is slightly from the end of the clad tube 4. The place where the distance is left is set, and the raising process starts from that place.

  While continuing the raising process, the pressing member 11 is raised from the downstream of the raising tool 9 so as to face the tool 9 and a part of the outer layer 3 is pressed by the outer layer pressing surface of the pressing member 11. As a result, the pressed portion is not raised by the tool 9 but remains in contact with the inner layer 2. Further, since the pressing member 11 has a fin pressing surface perpendicular to the outer layer pressing surface, the outer layer 3 raised by the raising tool 9 is bent at the minimum bending radius, and the outer layer 3 is formed on the cladding tube 4. It is molded into a fin 5 that stands upright at a right angle.

  According to the manufacturing method of the present invention, since the clad tube 4 having the inner layer 2 and the outer layer 3 is used as the raw tube, the fin 5 having the same thickness as the outer layer 3 can be formed by raising the outer layer 3. Therefore, if the thickness of the outer layer 3 is made sufficiently thin, the thickness of the fin 5 can be made sufficiently thin. At this time, since the process of forming the fin 5 is a process of causing the outer layer 3, the same effect is obtained as if the cutting depth is substantially constant regardless of the cutting depth of the cutter blade 7. It becomes easy to keep the height constant.

  According to the manufacturing method of the present invention, since the cut 8 is created in the outer layer 3 in advance and a part of the outer layer 3 is raised from the cut 8 to form the fin 5, the outer layer 3 can be easily raised, It is easy to set the height of 5 to a desired height and to keep the height of the fin 5 constant.

  In addition, according to the manufacturing method of FIG. 1, the raising tool 9 is arranged with a gap 10 with respect to the outer peripheral surface of the cladding tube 4, so the roundness of the cladding tube 4 and the raising tool 9 with the cladding tube 4 are raised. The rotation coaxiality does not affect the wake-up. For this reason, the factor which the height of the fin 5 becomes non-uniform | heterogenous is excluded.

  In the heat transfer tube of the present invention, the fins 5 can be made thin and the height of the fins 5 can be made constant, so that there is no variation depending on the individual or location, and high heat transfer performance can be obtained.

It is a sectional side view of the heat exchanger tube which shows one Embodiment of this invention. It is a fragmentary sectional side view of the heat exchanger tube for demonstrating the manufacturing method of the heat exchanger tube of this invention. It is sectional drawing perpendicular | vertical to the axis | shaft of a heat exchanger tube in the location where a raising tool is made to act.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat transfer tube 2 Inner layer 3 Outer layer 4 Clad tube 5 Fin 6 Inner surface groove 7 Cutter blade 8 Notch 9 Raising tool 10 Crevice

Claims (4)

  A heat transfer tube comprising a clad tube having an inner layer and an outer layer, wherein a part of the outer layer is a fin protruding in the radial direction.   The heat transfer tube according to claim 1, wherein the fin extends by spirally winding the outer periphery of the clad tube.   The heat transfer tube according to claim 1 or 2, further comprising a spiral groove on an inner surface of the inner layer.   A method of manufacturing a heat transfer tube, wherein a cut is made in the outer layer from the outside of a clad tube having an inner layer and an outer layer, and a fin is formed by raising a part of the outer layer from the cut and projecting in a radial direction.

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