DE102006018688B4 - Method for bending multiport tubes for heat exchangers - Google Patents

Abstract

A method of bending multiport tubes for heat exchangers, wherein the multiport tube is provided with an inflow portion, a curved central portion and a return portion for a refrigerant and the heat exchanger comprises a collector, on the at least two parallel offset multiport tubes with ribs arranged therebetween at both ends with the inflow portion and the reflux section are connected,
characterized by the following steps:
a. Bending the multiport tube (1) on the narrow longitudinal side (10) in the central region (3) at an angle of 180 ° to the longitudinal axis (11) directed in a temperature range between room temperature and a maximum temperature of 150 ° C, wherein the multiport tube (1 ) is fixed in its cross-sectional area (6) during the bending process, is bent around a mandrel by means of a bending device and is bent over as a result of the spring-back of the multiport tube (1),
b. Processing of the multiport tube (1) in the inner bending radius (12) and / or in the outer bending radius (13) during bending, so that after completion of the bending process, the entire cross-sectional area (6) and the ...

Description

The The invention relates to a method for bending multiport tubes for heat exchangers, wherein the multiport tube with an inflow section, a curved middle Area and a reflux section for transport for a refrigerant is provided and the heat exchanger a collector, at the at least two parallel offset multi-tube with interposed ribs on both sides with the Inflow section and the reflux section are connected.

The multiport tubes are z. B. CO ₂ pressure pipes, which may be formed as high pressure and low pressure pipes.

The conventional Bending method for the multiport tubes is that the entire multiport tube in a middle area of its total length, first at an angle from 90 ° to the longitudinal axis twisted the multiport tube, then at an angle of 180 ° across the longitudinal axis bent and then again in the middle area by an angle of Twisted 90 ° will, so that the reflux section parallel opposite as the inflow section runs.

By the two rotational movements, the multiport tube is a z. B. Leave 15 mm wide rib plane in the middle area. The the Multiport tube associated Thus, the pipe wall can not be used completely for heat transfer.

One Problem of the conventional Procedure is also that, by design, not the possibility is present to use the entire area flowed through.

A flat tube heat exchanger with a collector is in the document DE 39 36 109 A1 described. The heat exchanger has a number of flat tubes, which are arranged one above the other with the interposition of corrugated fins at a mutual distance. Each flat tube has at least one inflow section and one inflow section, via which an inlet formed on the side of the heat exchanger is flow-connected to an outlet of the respective flat tube formed at the same location of the heat exchanger, the sections having a rectangular cross-section.

each Flat tube has a rectilinear inflow portion and a rectilinear Return leg out, over a curved one Section are interconnected. The inflow section and the Return leg taper a flat tube each end in width. The curved section points to his both ends also a tapered in cross-section on, with the rejuvenated Cross sections of the curved Section to the rejuvenated Cross sections of the inflow section and the reflux section attached are.

One The problem is that the two - sided taper at the connection of the curved section within the bent flat tube reduces the refrigerant flow rate and thus the heat transfer performance limited becomes.

Furthermore, a flat tube with a reverse arc section and a heat exchanger constructed therewith are referred to in the document DE 103 06 848 A1 described, wherein the flat tube is bent such that its two adjoining, planar pipe sections extend in the longitudinal direction with opposite flow directions and with at least in the transverse direction offset longitudinal axes. The reverse bend portion is formed such that a main bending axis is parallel to the flat tube plane and at a predetermined angle to the tube longitudinal extent, wherein the flat tube plane is determined by the length and width extent of the flat tube.

For a heat exchanger tube block are in the document EP 1 036 296 B1 Described flat tubes, which have at least one Umkehrbogenabschnitt, in which each of the flat tube is bent such that its two adjoining, planar pipe sections in the longitudinal direction with opposite flow directions and with at least offset in the transverse direction longitudinal axes. The reverse curve section encloses the flat tube transverse axis at an angle of at most 45 ° with a plane parallel to the longitudinal direction and transverse direction and perpendicular to a stacking direction.

One Problem of the reverse arc sections is that in it reduces the cross-section of the flat tube and consequently the refrigerant flow rate becomes. Furthermore the wall thicknesses in the turnaround sections are reduced, one consistent Rib formation on the entire flat tube is not available.

It is a method for bending a thick-walled metal round tube to a relatively small radius, in which in a first bending operation, the unilaterally heated round tube is compressed on this side, in the document DE 1 177 908 A described, after which in a second bending operation in the opposite direction, a compression of the tube wall is carried out on the opposite side and finally the round tube is bent into the final manifold shape, the second Biegevor passage beyond the stretched position and then - after heating the inner side opposite side - is continued until reaching the desired final shape of the manifold. During the second bending process, the later outer side of the manifold can also be cooled.

It is a method for bending a thick-walled metal round tube to a relatively small radius, in which in a first bending operation, the unilaterally heated round tube is compressed on this side, in the document DE 1 177 908 A described, according to which in a second bending operation in the opposite direction upsetting the tube wall is carried out on the opposite side and finally the round tube is bent into the final manifold shape, the second bending process beyond the stretched position and then - after heating the inner side opposite side - is continued until reaching the desired final shape of the manifold. During the second bending process, the later outer side of the manifold can also be cooled.

The Problem is that the bending operations on a metal round tube take place and affect two upsets on different ones opposite Side of the metal round tube done. By the mutual upsetting can the structure of the metal round tube can be changed and thus Weak spots form, the high pressures of the flowing refrigerant not withstand.

Another method for forming a bend in a round tube is in the document GB 691 996 A described, wherein the round tube is subjected in an order of bending operations, each process, after the first operation, reduces the radius of curvature in a flat bend. In each operation, the length of the round tube acted upon by bending does not exceed the length of the round tube obtained after bending. It should be heated to forging temperature before the bending process or during the bending process, the area of the round tube, which is present after the bend inside the bend.

One Problem is that the one curvature of the round tube must be heated to forging temperature, so that the length before or to remain the same after bending, but which causes the wall thickness both in the inner curvature be strengthened as well as in the outer curvature and therefore an additional one Material costs is given.

Another method for producing pipe elbows as uniform as possible wall thickness is in the document DE 471 645 A described, wherein a round tube, which is correspondingly thicker Wandwand than on the opposite side, used and bent such that the strong-walled part forms the curvature outside, the weak-walled part forms the curvature inside.

One Problem exists in the special production of the round tubes, whereby a high material or accuracy effort for the production of round tubes with at least half Wall thickness differences to achieve a uniform wall thickness when bending. On the associated straight Part tube pieces The cost of materials is high, since one side of the tube with more Material is provided.

It is also an education of tube bends with a uniform wall thickness in the bending part by means of a multi-layer structure in bending a straight round tube, which is provided with an inner lining layer and is gently bent in the intended direction, in the document JP 600 18 230 A described.

The inner covering layer is od by means of an automatic adhesive welding. Like. On the entire inner surface the pipe wall attached and the round tube is in small steps bent in the intended direction. The round tube, that of the bend is undergone during the implementation the bending steps in the inner radius of curvature ground and gradually in the outer radius of curvature strengthened so that after a series of slight bends and associated respectively same processing steps a curved round tube with the same Cross sectional area and reached the same wall thickness becomes.

The Problem is that a consequence of elaborate work processes and Material movements during of the bending process is present.

The Problem is that the bending operations on a metal round tube take place and affect two upsets on different ones opposite Side of the metal round tube done. By the mutual upsetting can the structure of the metal round tube can be changed and thus Weak spots form, the high pressures of the flowing refrigerant not withstand.

Another method for forming a bend in a round tube is in the document GB 691 996 A described, wherein the round tube is subjected in an order of bending operations, each process, after the first operation, the Radius of curvature reduced in a plane bend. In each operation, the length of the round tube acted upon by bending does not exceed the length of the round tube obtained after bending. It should be heated to forging temperature before the bending process or during the bending process, the area of the round tube, which is present after the bend inside the bend.

One Problem is that the one curvature of the round tube must be heated to forging temperature, so that the length before or to remain the same after bending, but which causes the wall thickness both in the inner curvature be strengthened as well as in the outer curvature and therefore an additional one Material costs is given.

Another method for producing pipe elbows as uniform as possible wall thickness is in the document DE 471 645 A described, wherein a round tube, which is correspondingly thicker Wandwand than on the opposite side, used and bent such that the strong-walled part forms the curvature outside, the weak-walled part forms the curvature inside.

One Problem exists in the special production of the round tubes, whereby a high material or accuracy effort for the production of round tubes with at least half Differences in wall thickness to achieve a uniform wall thickness when bending. On the associated straight Part tube pieces the cost of materials is high, since the one side of the round tube with more material is provided.

It is also an education of tube bends with a uniform wall thickness in the bending part by means of a multi-layer structure in bending a straight round tube, which is provided with an inner lining layer and is gently bent in the intended direction, in the document JP 600 18 230 A described.

The inner covering layer is od by means of an automatic adhesive welding. Like. On the entire inner surface the pipe wall attached and the round tube is in small steps bent in the intended direction. The round tube, that of the bend is undergone during the implementation the bending steps in the inner radius of curvature ground and gradually in the outer radius of curvature strengthened so that after a series of slight bends and associated respectively same processing steps a curved round tube with the same Cross sectional area and reached the same wall thickness becomes.

The Problem is that a consequence of elaborate work processes and Material movements during of the bending process is present.

Of the Invention is based on the object, a method for bending Multiport tubes for heat exchangers specify that is designed so suitable that after the bending process the cross-sectional area in the reverse curve section and the local wall thickness is not reduced become. Furthermore, a few bending steps should be made.

The The object is solved by the features of the claim.

• a. Biegen des Multiportrohres an der schmalen Längsseite im mittleren Bereich in einem Winkel von 180° zur Längsachse gerichtet in einem Temperaturbereich zwischen Raumtemperatur und einer maximalen Temperatur von 150°C, wobei das Multiportrohr während des Biegeprozesses in seiner Querschnittsfläche fixiert, mittels einer Biegevorrichtung um einen Dorn gebogen und infolge des Rückfederns des Multiportrohres überbogen wird, und
• b. Bearbeiten des Multiportrohres im inneren Biegeradius und/oder im äußeren Biegeradius während des Biegens, so dass nach Abschluss des Biegevorgangs die gesamte Querschnittsfläche und die Dicke der Wandung des Multiportrohres auch in den Biegeradien beibehalten werden und wobei die Rohroberfläche und die Rohrunterfläche des Multiportrohres eben und parallel zueinander gerichtet ausgebildet bleiben.

In the method of bending multiport tubes for heat exchangers, wherein the multiport tube is provided with an inflow portion, a curved central portion, and a reflux portion for transporting a refrigerant, and the heat exchanger has a header on which at least two parallel staggered flat tubes having ribs interposed therebetween, respectively connected at both ends with the inflow section and the reflux section, the following steps are carried out according to the characterizing part of the claim:

• a. Bending the multiport tube on the narrow longitudinal side in the central region at an angle of 180 ° to the longitudinal axis in a temperature range between room temperature and a maximum temperature of 150 ° C, wherein the multiport tube fixed in its cross-sectional area during the bending process, by means of a bending device around a mandrel bent and is bent over as a result of the springback of Multiportrohres, and
• b. Machining the Multiportrohres in the inner bending radius and / or in the outer bending radius during bending, so that after completion of the bending process, the entire cross-sectional area and the thickness of the wall of the Multiportrohres are maintained in the bending radii and wherein the pipe surface and the lower tube surface of the Multiportrohres flat and parallel stay trained trained to each other.

Of Furthermore, there is also the possibility that Flat tube cold, ie at room temperature, at about 20 ° C, to bend, where appropriate, to change the given bending parameters.

By a given bending speed can be the deformation of the inner Cross sectional area be largely influenced.

An advantage is that a power gain is obtained because through the Beibe attitude of the parallel plane of the planar pipe surface and flat tube surface, the pipe wall is provided throughout to connect the ribs and thus can be used completely for heat transfer.

In the multiport tube manufactured and bent by the method with an inflow section, a curved middle section and a reflux section for transport for a refrigerant for Heat transfer, wherein the heat exchanger a Collector has, at the at least two parallel offset flat tubes with interposed ribs on both sides with the Inflow section and the reflux section are connected, is the middle portion of the multiport tube provided with a flat bend at an angle of 160 ° to 180 °, the whole Bending radius the cross-sectional area and the thickness of the wall of the multiport tube is made constant and the tube surface in parallel to the lower surface of the pipe throughout are directed to the middle area.

The the whole area of the flat tube is used in the bending radius.

The Multiport tubes are processed in the bending radius or during the Bending process thickened in the bending radius.

When Heat exchanger can be a compact highly effective triple-fluid heat exchanger be provided, which has a collector, to which the curved Multiport tube together with other identically bent multiport tubes with the end portions of the inflow portion and the reflux portion guided is.

The bent multiport tubes can be used in particular in combined CO ₂ - / air / glycol heat exchangers, which includes a head collector (collector) for the CO ₂ flow.

For the development of a heat exchanger with a predetermined current / a predetermined current for the flow of CO ₂ -Kältemittels a certain tube geometry is provided. Due to the bending of the radii of radius on the long side of the multiport tubes, a completely flat surface is achieved within the middle region, whereby a rib can then be introduced continuously between the middle regions between two adjacent, submerged multiport tubes.

The Invention allows it that the entire flowed through Cross sectional area is optimally utilized by the flat bending process.

Consequently The construction can improve the heat transfer performance become.

The Invention opened also the possibility of thermodynamic Advantages of soldering to reach the multiport tubes with the ribs.

The Invention is based on an embodiment explained in more detail by means of several drawings.

It demonstrate:

1 a schematic representation of a bent multiport tube according to the invention,

2 a cross section of the bent multiport tube along the line AA in 1 and

3 an enlargement of the cross section of a bent multiport tube after 2 with measurements.

The following are the 1 and 2 considered together.

In 1 is a bent multiport tube 1 with an inflow section 2 , a curved middle area 3 and a reflux section 4 shown for transport for a refrigerant for heat transfer, wherein a heat exchanger (not shown) has a collector, on the at least two parallel offset multi-port tubes with interposed ribs both ends with the inflow section 2 and the reflux section 3 are connected.

The middle area 3 of the multiport tube 1 is with a flat bend 5 provided at an angle of 160 ° to 180 °, with the middle range 3 the cross-sectional area 6 and the thickness of the wall 7 of the multiport tube 1 largely constant and the tube surface 14 parallel to the lower surface of the pipe 15 consistently in the middle area 3 are directed.

As a refrigerant, a triple combination of carbon dioxide -CO ₂ -, air and glycol can be used.

The multiport tube 1 can have a rectangular cross-sectional area 6 with respect to one side of the rectangle in the range of 6.0 mm to 8.5 mm and with respect to the other perpendicular side of the rectangle in the range of 1.5 mm to 2.8 mm, the multiport tube 1 is bent centrally at an angle of 180 ° in the transverse direction. The multiport tube 1 has connections as a port entrance 8th for the inflow section 2 and a port output 9 for the reflux section 4 , where the two ports 8th . 9 with the collector (not shown) after a Verlö tion.

In 3 is an enlarged view of the cross section of a bent multiport tube 1 to 2 shown in section AA, wherein in an altered manner instead of rectangular cross-sectional areas 6 rounded cross-sectional areas are drawn. In the middle area 3 is the plane bend 5 , In the reflux section 4 as well as in the inflow section 2 For example, there are five capillary channels through which the refrigerant flows at high pressure. The essential cross-sectional area dimensions are marked with 7.9 mm × 2.1 mm, which are in the above-mentioned dimensional ranges from 6.00 mm to 8.5 mm and 1.5 mm to 2.8 mm.

After the process of bending there is the possibility of the continuous pipe surfaces 14 and pipe bottoms 15 the curved flat tubes 1 to be used as complete rib connection surfaces.

• a. Biegen des Multiportrohres 1 an der schmalen Längsseite 10 im mittleren Bereich 3 in einem Winkel von 180° zur Längsachse 11 gerichtet in einem Temperaturbereich zwischen Raumtemperatur und einer maximalen Temperatur von 150°C, wobei das Multiportrohr 1 während des Biegeprozesses in seiner Querschnittsfläche 6 fixiert, mittels einer Biegevorrichtung um einen Dorn gebogen und infolge des Rückfederns des Multiportrohres 1 überbogen wird, und
• b. Bearbeiten des Multiportrohres 1 im inneren Biegeradius 12 und/oder im äußeren Biegeradius 13 während des Biegens, so dass nach Abschluss des Biegevorgangs die gesamte Querschnittsfläche 6 und die Dicke der Wandung 7 des Multiportrohres 1 auch in den Biegeradien 12, 13 beibehalten werden und wobei die Rohroberfläche 14 und die Rohrunterfläche 15 des Multiportrohres 1 eben und parallel zueinander gerichtet ausgebildet bleiben.

The method of bending multiport tubes for heat exchangers, wherein the multiport tube 1 with an inflow section 2 , a curved middle area 3 and a reflux section 4 is provided for transporting a refrigerant and the heat exchanger has a collector, at the at least two parallel offset multi-port tubes with ribs arranged therebetween at both ends with the inflow section 2 and the reflux section 4 are connected,
has the following steps:

• a. Bending the multiport tube 1 on the narrow longitudinal side 10 in the middle area 3 at an angle of 180 ° to the longitudinal axis 11 directed in a temperature range between room temperature and a maximum temperature of 150 ° C, wherein the multiport tube 1 during the bending process in its cross-sectional area 6 fixed, bent by a bending device around a mandrel and due to the springback of the multiport tube 1 will turn over, and
• b. Editing the multiport tube 1 inside bending radius 12 and / or in the outer bending radius 13 during bending, so that after completion of the bending process, the entire cross-sectional area 6 and the thickness of the wall 7 of the multiport tube 1 also in the bending radii 12 . 13 be maintained and the pipe surface 14 and the pipe bottom 15 of the multiport tube 1 stay flat and parallel to each other.

During bending, the thickness of the wall can be 7 of the multiport tube 1 be set consistently.

In a multi-flow CO ₂ / air / glycol heat exchanger, the curved CO ₂ multi-port pipes 1 only on one side at the ports 8th . 9 fixed, which belongs to the collector.

The multiport tubes according to the invention 1 have as material AA 3103 or AA 6003.

Of the Bending process can be performed at room temperature, e.g. B. 20 ° C, at a maximum operating temperature of 150 ° C and also in between.

The invention makes it possible that during bending a compression and also a deformation in the material thickness of the wall 7 of the multiport tube 1 be avoided. In this case, the deformation of the inner cross-sectional area can be largely influenced by a predetermined bending speed, it being expedient to change the bending parameters.

1

Multiport tube

2

inflow section

3

middle Area

4

Return leg

5

level bend

6

Cross sectional area

7

wall

8th

connection

9

connection

10

long side

11

longitudinal axis

12

internal bending radius

13

Outer bending radius

14

pipe surface

15

Pipe undersurface

Claims (1)

A method of bending multiport tubes for heat exchangers, wherein the multiport tube is provided with an inflow portion, a curved central portion and a return portion for a refrigerant and the heat exchanger comprises a collector, on the at least two parallel offset multiport tubes with ribs arranged therebetween at both ends with the inflow portion and the reflux section, characterized by the following steps: a. Bending the multiport tube ( 1 ) on the narrow longitudinal side ( 10 ) in the middle area ( 3 ) at an angle of 180 ° to the longitudinal axis ( 11 ) in a temperature range between room temperature and a maximum temperature of 150 ° C, wherein the multiport tube ( 1 ) during the bending process in its cross-sectional area ( 6 Fixed), bent by a bending device around a mandrel and due the springback of the multiport tube ( 1 ), b. Editing the multiport tube ( 1 ) in the inner bending radius ( 12 ) and / or in the outer bending radius ( 13 ) during bending, so that after completion of the bending process, the total cross-sectional area ( 6 ) and the thickness of the wall ( 7 ) of the multiport tube ( 1 ) also in the bending radii ( 12 . 13 ) and the pipe surface ( 14 ) and the lower surface of the pipe ( 15 ) of the multiport tube ( 1 ) stay flat and parallel to each other.