JP2005207710A - Heat-transfer pipe with fin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve heat efficiency and allow a fin to be integrally molded from a material pipe easily. <P>SOLUTION: A wave-shape pipe has a fin 5 long in a peripheral direction with clearance in between. The fin 5 double-folds a front-rear wall in a pipe axis direction and make it closely contact. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat transfer tube with fins.

As this kind of finned heat transfer tube, as shown in Patent Document 1, it is a finned heat transfer tube used in a double-tube type liquefied natural gas vaporizer, and is installed on the outer peripheral surface of the tube and has a tube shaft. There are known ones provided with external fins extending in a spiral shape in the direction.
JP-A-8-183971

In order to form the outer fins in a spiral shape over the pipe axis direction, it is necessary to cut the fins by cutting or to join the fins to a straight pipe by welding.
For this reason, since it is difficult to make the fin interval close, it is difficult to further improve the thermal efficiency by narrowing the fin interval. Further, if the process is complicated by cutting or welding, the manufacturing cost increases.
An object of this invention is to provide the heat exchanger tube with a fin which can solve such a problem.

  It is an object of the present invention to provide a finned heat transfer tube that can improve thermal efficiency and reduce manufacturing costs by integrally forming fins from a material pipe.

In order to achieve the above object, the present invention has taken the following measures. That is,
The corrugated tube includes fins 5 that are long in the circumferential direction and spaced apart in the tube axis direction. The fins 5 are close to each other by folding the front and rear walls in the tube axis direction in two.
Thus, by integrally forming the fins 5 from the material pipe, the thermal efficiency can be improved and the manufacturing cost can be reduced.
Convex portions 3 and concave portions 4 are alternately provided in the tube wall 2 at intervals in the tube axis direction, and fins 5 are formed in the vicinity of the center of the protrusion portion 3 by folding the front and rear walls in the tube axis direction close to each other. .

Thereby, the fin 5 can be more easily folded in half using the shape of the convex part 3, and the manufacturing cost can be further reduced. Moreover, the convex part 3 and the concave part 4 provided on the pipe wall 2 make it easy for turbulent flow to occur in the fluid inside and outside the pipe, and the thermal efficiency can be further improved.
The fin 5 is formed in a ring shape or a spiral shape in the tube axis direction.
This facilitates processing of the finned heat transfer tube 1.

  According to the present invention, by integrally forming the fin from the material pipe, the thermal efficiency can be improved and the manufacturing cost can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the finned heat transfer tube 1 </ b> A according to the first embodiment of the present invention includes a straight tubular tube end portion 13 at an end portion, and is adjacent to the tube end portion 13 and has a tube wall in the tube axis direction. 2 forms convex portions 3 and concave portions 4 alternately.
The recess 4 is a recess provided in a ring shape in the tube circumferential direction of the tube wall 2, and is provided at intervals in the tube axis direction so that a straight tubular material pipe is contracted. The diameter is small. The tube wall 2 provided continuously from the concave portion 4 to the convex portion 3 is linear, and is shaped so that the cross section is V-shaped.

The convex portion 3 is a portion protruding in the radially outward direction adjacent to the concave portion 4 and is connected in a ring shape in the pipe circumferential direction, and the fin 5 is provided in the circumferential direction in the vicinity of the center (top portion). Since the pipe is expanded, the diameter of the pipe is larger than that of the concave portion 4, and the pipe wall 2 connected to the concave portion 4 is linear, and has a triangular shape that bulges radially outward in a sectional view.
When the convex portions 3 and the concave portions 4 are alternately provided in the tube axis direction, turbulence can be generated in the fluid moving inside and outside the tube, and the heat transfer area can be increased as compared with the straight tube. The heat exchange rate can be dramatically improved by the effect.

The fin 5 has a tube wall 2 in the vicinity of the central portion of the convex portion 3 that is folded close to the front and rear walls in the tube axis direction, and the folded tube wall 2 is erected in the radially outward direction. A ring-shaped fin 5 is formed. The projecting end portion 7 of the fin 5 is polymerized by applying plastic deformation to such an extent that the metal material does not break, and the tube wall 2 is brought into close contact with the base end portion 6. The tube wall 2 may be in contact with the proximal end portion 6 or may have a slight gap.
Since the fins 5 can be provided densely as compared with welding or the like, the fins 5 can be provided densely to further improve the thermal efficiency. Further, since the fins 5 can be integrally formed from the material pipe, the manufacturing cost can be reduced.

As shown in FIG. 2, the finned heat transfer tube 1 </ b> A has a corrugated tube in which the recess 4 is pressed in the circumferential direction of the metal material pipe and the recesses 4 are provided at intervals in the tube axis direction. Form. When the pressing die portion 9 has a triangular shape in cross section, the concave portion 4 becomes a V-shaped groove as in the first embodiment. If the recess 4 is provided in a ring shape in the circumferential direction of the material pipe, the material pipe can be easily fixed in the subsequent contraction process. Therefore, the material pipe or the recess forming die 8 is preferably processed while rotating in the circumferential direction.
Next, the clamping mold 10a and the clamping mold 10b are inserted into the recesses 4 formed at a predetermined interval in the tube axis direction, and compressed in the tube axis direction until they come into contact with each other. When the sandwiching mold 10a and the sandwiching mold 10b are brought into contact with each other, the sandwiching mold 10a and the sandwiching mold 10b are sandwiched so as to form an inner mold portion 12 that is held in a triangular shape corresponding to the convex portion 3 in a sectional view. If the mold 10a and the clamping mold 10b are designed, the material pipe is compressed in the tube axis direction and at the same time is expanded along the inner mold part 12, so that the convex part 3 is formed and the fin 5 is also formed. .

In the pipe expansion forming of the material pipe, it is preferable to expand the pipe by applying a high-pressure gas or liquid to the inside of the pipe or by preparing a fitting. Moreover, the existing wavy tube can be expanded and formed as a material pipe. In the processing method, when the material pipes or the clamping dies 10a and 10b are pipe-expanded while being fed in the pipe axis direction, the fins 5 that are spirally continuous in the pipe circumferential direction can be formed.
By using the said processing method, the fin 5 can be integrally molded from a raw material pipe, a thermal efficiency can be improved, and manufacturing cost can be made low. Further, by making the fin 5 ring-shaped or spiral, the finned heat transfer tube 1A can be easily processed.

In the finned heat transfer tube 1B of the second embodiment, as shown in FIG. 2, the tube wall 2 from the convex portion 3 to the concave portion 4 is curved, and the convex portion 3 bulges out in the radial direction. It becomes a circle. The recess 4 is also a straight tube having a smaller tube diameter than the tube end 13. The finned heat transfer tube 1 according to the second embodiment can be obtained by designing the recess forming die 8 and the inner die portion 12 to have an umbilical shape and processing them.
The finned heat transfer tube 1 </ b> B of the second embodiment can also be obtained by expanding and forming an existing corrugated tube in which the convex portion 3 swells in a hemispherical shape in the radially outward direction. Moreover, although it exists in the tendency which becomes difficult compared with 1st Embodiment, a heat-transfer area becomes large and can improve a thermal efficiency more.

As shown in FIG. 3, the finned heat transfer tube 1 </ b> C of the third embodiment has a “<” shape that is bent in the middle of the tube wall 2 from the convex portion 3 to the concave portion 4 and convex in the radially outward direction. The concave portion 4 has a U-shaped groove shape having a smaller tube diameter than the tube end portion 13. The recessed portion forming die 8 is shaped like a paddle like the second embodiment, and the inner die portion 12 is designed to have a pentagonal shape and processed using this to obtain the finned heat transfer tube 1 of the third embodiment. Can do.
The finned heat transfer tube 1 </ b> C of the third embodiment shows that a heat sink tube with a fin having a complicated shape can be obtained by combining different recessed portion forming molds 8 and inner mold portions 12. It shows that the inner mold part 12 does not need to have the same shape. Further, by processing using an existing corrugated tube having U-shaped grooves provided in the circumferential direction at intervals, the fins 5 can be easily formed by tube expansion molding as in the second embodiment, and the thermal efficiency can be improved. Manufacturing costs can be reduced.

As shown in FIG. 4, the finned heat transfer tube 1 </ b> D according to the fourth embodiment has the tube walls 2 alternately formed with the concave portions 4 that are gently recessed with the fins 5 in the tube axis direction. The convex part 3 shown in the embodiment does not exist. It can be obtained by expanding and forming the material pipe formed into a corrugated tube by rolling or bulging or the like with the flat sandwiching molds 10 and 11.
It has an advantage that the finned heat transfer tube 1D can be easily processed using a flexible tube or the like that is generally available as a material pipe.
In the present invention, the shape of each member and the positional relationship of front / rear / left / right / upper / lower are best configured as shown in FIGS. However, it is not limited to the said embodiment, A member, a structure can be variously deformed, and a combination can also be changed.

For example, grooves are formed in the inner and outer peripheral surfaces of the tube wall 2 to increase the heat transfer area to further improve the thermal efficiency, or the heat transfer area can be reduced using a porous or etched metal material that has been roughened. It can also be increased to further improve thermal efficiency.
Further, the interval between the convex portion 3 and the concave portion 4 can be arbitrarily selected, and the interval between the convex portions 3 is increased so that the ring-shaped convex portion 3 appears at regular intervals. The recesses 4 can be provided smoothly and continuously so as to have a front-view wave shape.
The shape of the inner mold portion 12 can be a polygon or curved surface other than those in the first to fourth embodiments. In addition, the base end portion 6 of the fin 5 is most improved in the thermal efficiency when it is formed in the central portion of the convex portion 3, but the fin 5 may be in the vicinity of the central portion.

It is a partial cross section front view of 1st Embodiment of this invention. It is explanatory drawing which shows the method of processing a fin. It is a partial cross section front view of 2nd Embodiment. It is a partial cross section front view of 3rd Embodiment. It is a partial cross section front view of 4th Embodiment.

Explanation of symbols

1 Heat Transfer Tube with Fin 3 Convex 4 Concave 5 Fin

Claims (3)

  A corrugated pipe having fins (5) elongated in the circumferential direction at intervals in the pipe axis direction, wherein the fin (5) has two front and rear walls in the pipe axis direction folded in close proximity to each other. Heat transfer tube with fins.   The tube wall (2) is provided with convex portions (3) and concave portions (4) alternately at intervals in the tube axis direction, and the front and rear walls in the tube axis direction are folded in two near the center of the convex portion (3). A finned heat transfer tube characterized by forming fins (5) close to each other.   The finned heat transfer tube according to claim 1 or 2, wherein the fin (5) is formed in a ring shape or a spiral shape in a tube axis direction.

Images