CN111629844A - Metal round tube, heat exchanger provided with same, pipe bender, and method for bending metal round tube - Google Patents

Metal round tube, heat exchanger provided with same, pipe bender, and method for bending metal round tube Download PDF

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Publication number
CN111629844A
CN111629844A CN201980009269.7A CN201980009269A CN111629844A CN 111629844 A CN111629844 A CN 111629844A CN 201980009269 A CN201980009269 A CN 201980009269A CN 111629844 A CN111629844 A CN 111629844A
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CN
China
Prior art keywords
pipe
bending
metal round
pipe fitting
fitting recess
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201980009269.7A
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Chinese (zh)
Inventor
瀬直己
奥田丞志
藤泽秀行
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Noritz Corp
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Noritz Corp
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Publication date
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Publication of CN111629844A publication Critical patent/CN111629844A/en
Pending legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D9/00—Bending tubes using mandrels or the like
    • B21D9/14—Wrinkle-bending, i.e. bending by corrugating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D53/00—Making other particular articles
    • B21D53/02—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers
    • B21D53/06—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers of metal tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D7/00—Bending rods, profiles, or tubes
    • B21D7/02—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment
    • B21D7/024—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member
    • B21D7/025—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member and pulling or pushing the ends of the work
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D7/00—Bending rods, profiles, or tubes
    • B21D7/02—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment
    • B21D7/024—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member
    • B21D7/028—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member and altering the profile at the same time, e.g. forming bumpers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D9/00—Bending tubes using mandrels or the like
    • B21D9/05—Bending tubes using mandrels or the like co-operating with forming members
    • B21D9/07—Bending tubes using mandrels or the like co-operating with forming members with one or more swinging forming members engaging tube ends only
    • B21D9/073—Bending tubes using mandrels or the like co-operating with forming members with one or more swinging forming members engaging tube ends only with one swinging forming member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L43/00—Bends; Siphons
    • F16L43/001—Bends; Siphons made of metal
    • F16L43/002—Bends; Siphons made of metal and formed from sheet having a circular passage
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L9/00—Rigid pipes
    • F16L9/006—Rigid pipes specially profiled
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L9/00—Rigid pipes
    • F16L9/02—Rigid pipes of metal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F28D7/08—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being otherwise bent, e.g. in a serpentine or zig-zag
    • F28D7/082—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being otherwise bent, e.g. in a serpentine or zig-zag with serpentine or zig-zag configuration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/02—Tubular elements of cross-section which is non-circular
    • F28F1/06—Tubular elements of cross-section which is non-circular crimped or corrugated in cross-section
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2255/00—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Geometry (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)

Abstract

A metal round pipe (1) having a bent portion (10), wherein, in an axial cross-sectional view of the bent portion (10), an outer half portion (11b) of a peripheral wall portion (11) of the bent portion (10) is of such a non-arc outwardly convex shape: the central part in the direction (y) orthogonal to the bending radius direction (x) of the bending part (10) is an outermost peripheral part (13), and the distance (Lb) from the intermediate part (15) between a pair of base end parts (14) of the outer half part (11b) and the outermost peripheral part (13) to the tube center (O) is shorter than the distance (La) from the outermost peripheral part (13) to the tube center (O). Thus, the advantage of reducing the flow path resistance while suppressing the reduction in the cross-sectional area and the minimum inner width of the bent portion (10) can be obtained, and the metal round tube (1) can be easily and appropriately manufactured.

Description

Metal round tube, heat exchanger provided with same, pipe bender, and method for bending metal round tube
Technical Field
The present invention relates to a metal round pipe having a curved portion formed thereon and a technique related to the metal round pipe.
Background
As the heat transfer pipe of the heat exchanger, a metal circular pipe having a bent portion such as a U-letter shaped, meandering or spiral heat transfer pipe is often used. Such a circular metal tube having a bent portion is produced by bending a straight circular metal tube with a pipe bender (see, for example, patent documents 1 and 2).
As an example of the pipe bender, there is a pipe bender including a roller block 2 and a press die 3 as shown in fig. 6. The roller block 2 is provided with a semicircular 1 st pipe fitting recess 21, and the pressure die 3 is provided with a semicircular 2 nd pipe fitting recess 31. When the metal round pipe 1 is formed into the bent portion, the metal round pipe 1 is bent along the 1 st pipe fitting concave portion 21 of the roller block 2 while the metal round pipe 1 is sandwiched between the inner surface of the 1 st pipe fitting concave portion 21 and the inner surface of the 2 nd pipe fitting concave portion 31.
According to the above method, the metal round tube 1 having the bent portion 10 shown in fig. 7 is obtained. The bent portion 10 of the metal round tube 1 has the following configuration: the inner half 11a on the inner side of the center line C1 is semicircular, and the outer half 11b on the outer side of the center line C1 is recessed in a wide area in a direction closer to the center line C1. The portion Pa of the outer half portion 11b that should be the outermost portion is shifted by an appropriate dimension Lc in the direction approaching the center line C1.
When the bending portion 10 is formed, the inner half portion 11a is a compression side, and the outer half portion 11b is a tension side. Therefore, as the curvature radius R (bending radius) of the curved portion 10 is decreased, the amount of tensile deformation of the outer half portion 11b increases, the dimension Lc increases, and the outer half portion 11b becomes flat. In addition, when the bending speed of the metal round tube 1 is increased, the flattening becomes more remarkable.
However, according to the conventional technology, there is room for improvement as described below.
First, when the bent portion 10 is flattened in the above-described form, the cross-sectional area of the bent portion 10 becomes considerably smaller than the original cross-sectional area before bending. Further, the minimum inner width Ld of the bent portion 10 also becomes small. Therefore, the flow path resistance when the fluid is caused to flow through the metal round tube 1 becomes large. This is not preferable when the metal round tube 1 is used as, for example, a heat transfer tube of a heat exchanger.
Second, the flattening of the bent portion 10 becomes more remarkable as the bending speed of the metal round pipe 1 increases. Therefore, in order to suppress flattening of the bent portion 10, the bending speed needs to be reduced, but this deteriorates productivity.
On the other hand, conventionally, as described in patent document 3, for example, there is a method of: when a round metal pipe is bent, a mandrel bar is disposed inside a portion to be bent to prevent flattening of the bent portion. However, according to such a method, the work becomes complicated and the equipment cost becomes expensive. Further, when the entire length of the metal round tube is relatively long, or when a plurality of bending portions are provided in one metal round tube, the mandrel bar cannot be accommodated and arranged inside the portion to be bent, and the bending by the mandrel bar becomes difficult. Therefore, it is difficult to appropriately eliminate the above-described inconvenience.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2016-131977
Patent document 2: japanese laid-open patent publication No. 2012 and 135797
Patent document 3: japanese laid-open patent publication No. 2004-322186
Disclosure of Invention
Problems to be solved by the invention
An object of the present invention is to provide a round metal tube that can appropriately eliminate the above-described problems, a heat exchanger including the round metal tube, a pipe bender suitable for manufacturing the round metal tube, and a method of bending the round metal tube.
Means for solving the problems
In order to solve the above problems, the present invention adopts the following technical means.
The metallic round pipe according to claim 1 of the present invention has a bent portion whose outer half portion of a peripheral wall portion is a non-circular-arc outward convex shape in an axial sectional view of the bent portion: a central portion in a direction orthogonal to a bending radius direction of the bending portion is an outermost peripheral portion, and a distance from a middle portion between a pair of base end portions of the outer half portion and the outermost peripheral portion to a tube center is shorter than a distance from the outermost peripheral portion to the tube center.
Preferably, in an axial cross-sectional view of the bending portion, an inner half portion of the peripheral wall portion of the bending portion has a semicircular arc shape or a shape that is closer to the semicircular arc shape than the outer half portion.
Preferably, in an axial cross-sectional view of the curved portion, the outermost peripheral portion and the intermediate portion of the outer half portion are each curved or straight and convex outward, and no portion that is concave inward is provided in the outer half portion.
The heat exchanger according to claim 2 of the present invention includes a heat transfer pipe, and the heat transfer pipe is formed using the metal round pipe according to claim 1 of the present invention.
Preferably, the heat transfer pipe is a serpentine heat transfer pipe: the bent portion has a plurality of bent portions, and a plurality of straight tube portions arranged at intervals in a direction intersecting the axial length direction are connected in series by the plurality of bent portions.
The bending machine provided by the 3 rd technical solution of the present invention includes: a roller block having a 1 st pipe fitting recess formed in an outer circumferential surface thereof for fitting the inner surface side of the metal round pipe in the bending direction; and a press die having a 2 nd pipe fitting concave portion formed in a side surface thereof for fitting an outer surface side in a bending direction of the metal round pipe, the metal round pipe being capable of being sandwiched by inner surfaces of the 1 st pipe fitting concave portion and the 2 nd pipe fitting concave portion, a bent portion being formed in the metal round pipe, the 2 nd pipe fitting concave portion having a non-semicircular cross section as described above: the central portion of the 2 nd pipe fitting recess in the opening width direction is an innermost portion, and a distance from an intermediate portion between the innermost portion and a pair of edge portions of the 2 nd pipe fitting recess to a center between the pair of edge portions is shorter than a distance from the innermost portion to the center.
Preferably, the 1 st pipe fitting recess has a semicircular cross section or a shape closer to the semicircular cross section than the 2 nd pipe fitting recess.
Preferably, the innermost portion and the intermediate portion of the 2 nd pipe fitting concave portion are curved or straight in a concave shape in a cross-sectional view, and the 2 nd pipe fitting concave portion is not provided with a convex portion.
The method of bending a round metal pipe according to claim 4 of the present invention is a method of bending a round metal pipe using a pipe bender including a roller block having a 1 st pipe fitting recess formed on an outer surface thereof and a press die having a 2 nd pipe fitting recess formed on an inner surface thereof, the method including a step of bending the round metal pipe by sandwiching the round metal pipe between the inner surfaces of the 1 st pipe fitting recess and the 2 nd pipe fitting recess, and the pipe bender according to claim 3 of the present invention is used as the pipe bender.
Other features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.
Drawings
Fig. 1A is a plan view of a principal part showing an example of the metal round pipe of the present invention, and fig. 1B is an enlarged sectional view of IB-IB in fig. 1A.
Fig. 2A is a schematic plan sectional view showing an example of the pipe bender of the present invention, fig. 2B is a sectional view IIB-IIB of fig. 2A, and fig. 2C is a sectional view IIC-IIC of fig. 2A.
Fig. 3A is a schematic plan sectional view of the pipe bender shown in fig. 2A to 2C with a metal round pipe assembled therein, and fig. 3B is a sectional view taken along line IIIB-IIIB in fig. 3A.
Fig. 4 is a schematic plan cross-sectional view showing a state in which a bending portion is formed in the metallic round pipe by operating the pipe bender from the state shown in fig. 3A and 3B.
Fig. 5A is a top cross-sectional view showing an example of a heat exchanger configured by using a metal round tube having a bent portion, fig. 5B is a cross-sectional view from VB to VB of fig. 5A, and fig. 5C is a side view.
Fig. 6 is a main part sectional view showing an example of a conventional technique of a bender.
Fig. 7A is a plan view of a main part showing an example of a conventional technique of a metal round pipe, and fig. 7B is an enlarged cross-sectional view VIIB-VIIB in fig. 7A.
Detailed Description
Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
The same or similar elements as those in the conventional art shown in fig. 6 and 7 are denoted by the same reference numerals as those in the conventional art as appropriate.
The metal round tube 1 shown in fig. 1A is made of, for example, stainless steel, and has a bent portion 10 bent at an appropriate radius of curvature R within an angular range of 180 °. As shown in fig. 1B, in the axial cross-sectional view of the bending portion 10, the inner half 11a (on the inner side (left side) of the center line C1) of the peripheral wall portion 11 of the bending portion 10 has a semicircular arc shape. However, the inner half 11A is a portion in which the peripheral wall 11 is compressed in the circumferential direction, and is formed in a corrugated shape having a plurality of ridges 12 as shown in fig. 1A.
On the other hand, the outer half 11b (outside the center line C1) of the peripheral wall 11 of the curved portion 10 is convex outward in a non-circular arc shape. More specifically, the central portion (portion through which the center line C2 passes) of the outer half portion 11B in the y direction of fig. 1B (the vertical direction in the figure) is the outermost peripheral portion 13. The y direction is a direction orthogonal to the x direction, which is the bending radius direction of the bending portion 10 (the same direction as the facing direction of the inner peripheral portion and the outer peripheral portion of the bending portion 10, the left-right direction in fig. 1B). Here, the distance Lb from the pair of intermediate portions 15 to the tube center O is shorter than the distance La from the outermost peripheral portion 13 to the tube center O (relationship La > Lb). The intermediate portion 15 is a portion between the pair of proximal end portions 14 and the outermost peripheral portion 13 of the outer half portion 11 b. The pair of proximal portions 14 are portions that serve as proximal ends of the outer half 11b, and are near the center line C1 in the outer half 11 b.
The outermost peripheral portion 13 may be slightly displaced from the original position before the bending processing toward the pipe center O by the bending processing performed on the circular metal pipe 1 described later. Therefore, the distance from the portion of the intermediate portion 15 near the proximal end portion 14 to the tube center O may be longer than the distance La. However, in the present invention, the relationship La > Lb need not be satisfied over the entire region of the intermediate portion 15, and the distance Lb from at least a part of the intermediate portion 15 (for example, the central portion of the intermediate portion 15 or the vicinity thereof) to the tube center O may satisfy the relationship La > Lb.
This also applies to the relationship of the distances La 'and Lb' with respect to the innermost portion 31a and the intermediate portion 31c of the 2 nd pipe fitting concave portion 31 of the pressure die 3 described later.
In another aspect, the outer half portion 11b corresponds to a form in which the intermediate portion 15 is located closer to the tube center O than an arc a passing through three points, i.e., the pair of base end portions 14 and the outermost peripheral portion 13.
In the axial sectional view of the bending portion 10, the outer half portion 11b is not provided with an inwardly recessed portion, and the outermost peripheral portion 13 and the intermediate portion 15 are each curved so as to be outwardly convex. Their radii of curvature r1, r2 differ, for example r1 < r 2. However, the present invention is not limited to this, and one or both of the outermost peripheral portion 13 and the intermediate portion 15 may be, for example, non-curved (straight).
Next, an example of a bending machine a for forming the bent portion 10 and an example of a method for forming the bent portion 10 using the bending machine a will be described.
The pipe bender a shown in fig. 2A to 2C includes a roller block 2, a press mold 3, and a clamp mold 4.
The roller block 2 is horizontally rotatable about the shaft portion 20, and has a series of 1 st pipe fitting recesses 21 formed in the outer peripheral surface thereof. In a top cross-sectional view, the 1 st pipe fitting recess 21 has a curved portion 21a curved in an arc shape within an angular range of 180 ° and linear portions 21b and 21c connected to both ends of the curved portion 21 a. The 1 st pipe fitting recess 21 corresponds to the inner half 11a of the above-described bent portion 10, and specifically, as shown in fig. 2C, has a semicircular cross section (an inner surface having a semicircular arc shape). However, a plurality of recessed grooves 22 are provided at appropriate intervals on the inner surface of the 1 st pipe fitting recess 21, and the depth of the recessed grooves 22 is greater than the depth of the 1 st pipe fitting recess 21. The recessed portion 22 corresponds to the raised portion 12 shown in fig. 1A.
The press die 3 is a block-shaped member having a series of 2 nd pipe fitting recesses 31 formed in the side surface in the horizontal direction indicated by the arrow Na. The press mold 3 is located on the lateral side of the roller block 2, and is movable back and forth in the arrow Na direction, and is also movable back and forth in the horizontal direction of the arrow Nb intersecting the arrow Na direction, so as to be movable toward and away from the roller block 2.
The 2 nd pipe fitting recess 31 corresponds to the outer half 11b of the bent portion 10 described above. Specifically, as shown in fig. 2C, the 2 nd pipe fitting recess 31 has a non-semicircular cross section: the central portion in the vertical opening width direction is an innermost portion 31a, and a distance Lb 'from the pair of intermediate portions 31c to a center Oa between the pair of edge portions 31b of the 2 nd pipe fitting concave portion 31 is shorter than a distance La' from the innermost portion 31a to the center Oa. The intermediate portion 31c is a portion between each of the edge portions 31b and the innermost portion 31 a. The innermost portion 31a and the intermediate portion 31c are portions corresponding to the outermost peripheral portion 13 and the intermediate portion 15 of the bending portion 10 shown in fig. 1B, and preferably, the innermost portion 31a and the intermediate portion 31c are curved or non-curved (straight) in a concave shape in a cross-sectional view, and a convex portion is not provided in the 2 nd pipe fitting concave portion 31.
The clamp die 4 is a portion for clamping the metal round tube 1 between the roll block 2 and the metal round tube 1 to generate a drawing operation of the metal round tube 1. A 3 rd pipe fitting recess 41 having a semicircular cross section as shown in fig. 2B is provided on a side surface of the holding die 4. The clamp die 4 is configured such that when the roller block 2 is rotated about the shaft portion 20, the clamp die 4 is horizontally rotated about the shaft portion 20. Thus, the clamped state of the metal round tube 1 can be maintained by both the roller block 2 and the clamp die 4 so that the relative positional relationship between the clamp die 4 and the roller block 2 does not shift.
The bending portion 10 is formed in the metal round tube 1 by using the bending machine a as follows.
First, as shown in fig. 3A and 3B, the metal round tube 1 is set such that the inner surface side in the bending direction is fitted into the 1 st tube fitting concave portion 21 (straight portion 21B) of the roller block 2, and the outer surface side in the bending direction is fitted into the 2 nd tube fitting concave portion 31 of the press mold 3 and the 3 rd tube fitting concave portion 41 of the clamp mold 4. The press die 3 and the clamp die 4 are brought close to the roll block 2 side, and the metal round pipe 1 is clamped with a sufficient force so that the press die 3 and the clamp die 4 do not slide or the like with respect to the metal round pipe 1.
Next, in the set state, the roller block 2 and the clamp die 4 are horizontally rotated by 180 ° about the shaft portion 20. As a result, as shown in fig. 4, a part of the round metal tube 1 is bent to follow the bent portion 21a of the 1 st tube fitting recess 21 of the roller block 2, thereby forming a bent portion 10. The bending portion 10 has the same structure as the bending portion 10 described with reference to fig. 1A and 1B.
Thus, according to the processing method using the pipe bender a, the metal round pipe 1 having the bent portion 10 can be easily and appropriately manufactured. Further, when the roller block 2 and the clamp die 4 are rotated as described above, the tension or the amount of tension in the outer half portion 11b of the bending portion 10 can be adjusted by advancing the press die 3 in the arrow Nc direction.
Fig. 5A to 5C show an example of the heat exchanger HE. The plurality of heat transfer tubes 1A of the heat exchanger HE are formed in a plurality of bent portions 10 in the metal round tube 1, and thereby the entire heat transfer tube is formed in a meandering shape. More specifically, the heat transfer pipe 1A is configured as follows: the bending portion 10 is provided with a plurality of bending portions and a plurality of straight tube portions 18 arranged at intervals in a direction intersecting with an axial length direction, and the plurality of straight tube portions 18 are connected in series by the plurality of bending portions 10.
In the heat exchanger HE, the plurality of heat transfer tubes 1A are housed in the casing 5 in a state of being stacked at intervals in the vertical height direction. The casing 5 is provided with an air supply port 50 and an exhaust port 51 for combustion gas as heating gas. The end portions of the heat transfer tubes 1A are disposed in the headers 6a and 6b for inlet water and outlet water, and the hot and cold water supplied from the water inlet 60a of the header 6a is heated by the heat transfer tubes 1A and then reaches the header 6b, and hot water is discharged from the hot water outlet 60 b.
Next, the operation of the metal round tube 1 shown in fig. 1A and 1B will be described.
First, it is needless to say that the inner half portion 11a is not flattened and the outer half portion 11b is not formed into a largely flattened shape in the bending portion 10. Therefore, the cross-sectional area and the minimum inner width of the bending portion 10 can be increased as compared with the conventional technique shown in fig. 7A and 7B. Therefore, the flow path resistance when the fluid is caused to flow through the metal round tube 1 can be reduced. This is preferable in reducing the water flow resistance of the heat transfer tubes 1A of the heat exchanger HE shown in fig. 5A to 5C.
The outer half 11b of the bending portion 10 is configured such that the intermediate portion 15 is located closer to the tube center O than the outermost peripheral portion 13. Such a configuration is a configuration in which the lower part is the intermediate part 15: this portion is a portion where the outer half portion 11b of the bent portion 10 is elongated by receiving tension when the bent portion 10 is formed by machining, and a concave portion (displacement in a direction toward the pipe center O) is generated. Therefore, the outermost peripheral portion 13 of the outer half 11b can be recessed not largely in the direction closer to the tube center O. Therefore, the following are preferable: even when the bending speed of the metal round pipe 1 is relatively high, flattening of the bent portion 10 can be appropriately avoided, the productivity of the metal round pipe 1 having the bent portion 10 can be improved, and the manufacturing cost can be reduced.
In the present embodiment, as described above, the outermost peripheral portion 13 and the intermediate portion 15 of the outer half portion 11b of the bending portion 10 are both curved so as to be convex outward in the axial cross-sectional view of the bending portion 10. Therefore, it is possible to more reliably prevent any portion of the outer half portion 11b from being largely recessed in the direction closer to the tube center O.
Since the inner half 11a of the curved portion 10 is semi-arc-shaped and is not recessed in the direction toward the pipe center O, it is more preferable to increase the cross-sectional area and the minimum inner width of the entire curved portion 10 and to reduce the flow path resistance. Further, unlike the present embodiment, even when the inner half portion 11a is not formed in a semicircular arc shape, the sectional area and the minimum inner width of the entire bending portion 10 can be made not so small by forming the inner half portion 11a in a shape (substantially semicircular arc shape) closer to a semicircular arc shape than the outer half portion 11 b.
The present invention is not limited to the above-described embodiments. The specific configurations of the respective parts of the metallic round tube, the heat exchanger, and the pipe bender according to the present invention can be freely changed in design within the range sought by the present invention. The specific configuration of each operation step of the method for bending a metal round pipe according to the present invention can be freely changed within the range intended by the present invention.
The present invention is mainly directed to preventing or suppressing flattening of the outer half portion of the bent portion of a metal round tube. Thus, the specific shape of the medial half can be selected according to various conditions. However, the inner half portion is preferably formed in a semicircular arc shape or a shape at least closer to a semicircular arc than the outer half portion (substantially semicircular arc shape).
The outermost peripheral portion and the intermediate portion of the outer half portion of the bent portion are preferably curved so as to be convex outward or at least non-curved (straight) and have a shape having no portion recessed inward.
The specific bending angle of the bending portion is not limited. In the above-described embodiment, the bent portion is formed in the angular range of 180 °, but instead, another bent angle such as 90 ° may be provided. The specific bending radius, the size and material of the metal round pipe to be bent, and the like are not limited.
The metal round tube to which the present invention is applied is suitably used as a heat transfer tube of a heat exchanger, but can be used for other applications.

Claims (9)

1. A metal round pipe having a bent portion, wherein,
in an axial sectional view of the bending portion, an outer half portion of a peripheral wall portion of the bending portion is a non-circular-arc outward convex shape: a central portion in a direction orthogonal to a bending radius direction of the bending portion is an outermost peripheral portion, and a distance from a middle portion between a pair of base end portions of the outer half portion and the outermost peripheral portion to a tube center is shorter than a distance from the outermost peripheral portion to the tube center.
2. A metal round tube according to claim 1,
in an axial cross-sectional view of the curved portion, an inner half portion of a peripheral wall portion of the curved portion has a semicircular arc shape or a shape that is closer to the semicircular arc shape than the outer half portion.
3. The metal round tube according to claim 1 or 2,
in an axial cross-sectional view of the bending portion, the outermost peripheral portion and the intermediate portion of the outer half portion are each curved or straight and convex outward, and no portion that is concave inward is provided in the outer half portion.
4. A heat exchanger is provided with a heat transfer pipe, wherein,
the heat transfer pipe is formed using the metal round pipe according to any one of claims 1 to 3.
5. The heat exchanger according to claim 4,
the heat transfer pipe is a serpentine heat transfer pipe: the bent portion has a plurality of bent portions, and a plurality of straight tube portions arranged at intervals in a direction intersecting the axial length direction are connected in series by the plurality of bent portions.
6. A pipe bender is provided, wherein,
this bending machine includes:
a roller block having a 1 st pipe fitting recess formed in an outer circumferential surface thereof for fitting the inner surface side of the metal round pipe in the bending direction; and
a press die having a side surface formed with a 2 nd pipe fitting recess into which the outer surface side in the bending direction of the metal round pipe is fitted,
the metal round pipe can be sandwiched by the inner surfaces of the 1 st pipe fitting recess and the 2 nd pipe fitting recess, and a bent portion can be formed in the metal round pipe,
the 2 nd pipe fitting recess is formed in a non-semicircular shape in cross section: the central portion of the 2 nd pipe fitting recess in the opening width direction is an innermost portion, and a distance from an intermediate portion between the innermost portion and a pair of edge portions of the 2 nd pipe fitting recess to a center between the pair of edge portions is shorter than a distance from the innermost portion to the center.
7. The bender according to claim 6,
the 1 st pipe fitting recess has a semicircular cross section or a shape closer to the semicircular cross section than the 2 nd pipe fitting recess.
8. The bender according to claim 6 or 7,
the innermost portion and the intermediate portion of the 2 nd pipe fitting concave portion are concavely curved or straight in a cross-sectional view, and a convex portion is not provided in the 2 nd pipe fitting concave portion.
9. A method for bending a metal round tube, wherein,
the bending method uses a pipe bender comprising a roller block with a 1 st pipe fitting concave part formed on the outer side surface and a pressure die with a 2 nd pipe fitting concave part formed on the inner side surface,
the bending method comprises a step of bending a circular metal pipe while sandwiching the circular metal pipe between the inner surfaces of the 1 st pipe fitting recess and the 2 nd pipe fitting recess,
the bending machine according to any one of claims 6 to 8 is used as the bending machine.
CN201980009269.7A 2018-01-26 2019-01-22 Metal round tube, heat exchanger provided with same, pipe bender, and method for bending metal round tube Pending CN111629844A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2018-011256 2018-01-26
JP2018011256A JP7174339B2 (en) 2018-01-26 2018-01-26 Pipe bender and metal round pipe bending method
PCT/JP2019/001777 WO2019146569A1 (en) 2018-01-26 2019-01-22 Round metal pipe, heat exchanger provided with same, pipe bender, and method for bend-processing round metal pipe

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CN111629844A true CN111629844A (en) 2020-09-04

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CN112496106A (en) * 2020-11-26 2021-03-16 南京华斯特机械科技有限公司 Forming processing method for condenser condensation pipe

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JP7363015B2 (en) * 2019-09-26 2023-10-18 株式会社ノーリツ Manufacturing method of pipe structure

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JPS57142723A (en) * 1981-01-30 1982-09-03 Imp Clevite Inc Manually operated type pipe bender
JPS6114022A (en) * 1984-06-29 1986-01-22 Matsushita Refrig Co Pipe bending method
JP2001334334A (en) * 2000-05-24 2001-12-04 Koa Seisakusho:Kk Method for manufacturing heat exchanger
US20070221365A1 (en) * 2006-03-24 2007-09-27 Evapco, Inc. U-shaped heat exchanger tube with a concavity formed into its return bend
CN205362472U (en) * 2016-01-26 2016-07-06 常州曼淇威制冷设备有限公司 Oval cross section snaking radiating copper pipe processes frock

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JPS54112771A (en) * 1978-02-24 1979-09-03 Hitachi Ltd Pipe bender
JPS57142723A (en) * 1981-01-30 1982-09-03 Imp Clevite Inc Manually operated type pipe bender
JPS6114022A (en) * 1984-06-29 1986-01-22 Matsushita Refrig Co Pipe bending method
JP2001334334A (en) * 2000-05-24 2001-12-04 Koa Seisakusho:Kk Method for manufacturing heat exchanger
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CN205362472U (en) * 2016-01-26 2016-07-06 常州曼淇威制冷设备有限公司 Oval cross section snaking radiating copper pipe processes frock

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112496106A (en) * 2020-11-26 2021-03-16 南京华斯特机械科技有限公司 Forming processing method for condenser condensation pipe
CN112496106B (en) * 2020-11-26 2021-08-20 佛山市顺德区同兴业实业有限公司 Forming processing method for condenser condensation pipe

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US20200348085A1 (en) 2020-11-05

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