Device for a heat exchanger for collecting and distributing a heat transfer fluid

Abstract

A device for a heat exchanger has a hollow cylindrical header and a plurality of flat tubes. A wall of the header includes a plurality of through openings. The flat tubes are received in the through openings through the wall into the inner cross-section of the header tube, and are aligned with the width of the flat tubes parallel to the direction of the inner dimension. A width of the flat tubes is greater than an inner dimension of the inner cross-section and is smaller than the outer dimension of the header tube, wherein the through openings are embodied as having grooves that continue in the wall of the header tube into the inner cross-section. The flat tubes, which are guided in the through openings through the wall, are arranged in the grooves.

Claims

1. A device for a heat exchanger for collecting and distributing a heat exchange fluid, comprising: a hollow cylindrical header tube having a wall, the wall having an outer diameter and enclosing an inner cross-section having an inner diameter, the wall including a plurality of openings formed therethrough; and a plurality of flat tubes, each of the flat tubes having an end received in the inner cross-section of the header tube through one of the openings, wherein a cross-sectional shape of each of the openings corresponds to a cross-sectional shape of the each of the flat tubes, a width of each of the flat tubes is greater than the inner diameter of the inner cross-section and smaller than the outer diameter of the header tube, wherein a pair of grooves extend from each of the openings into the wall of the header tube, and wherein opposing sides of each of the flat tubes are received in the grooves, wherein each of the flat tubes has a plurality of flow channels formed therein, wherein each of the flat tubes is arranged with one end face spaced from an end of each of the grooves formed in the wall, wherein each of the flat tubes is formed with a pair of opposing narrow sides, wherein a formation is formed in each of the grooves between each of the narrow sides of the end face of each of the flat tubes and the end of each of the grooves, wherein a first chamfer is formed in the header tube adjacent each of the openings, wherein a second chamfer is formed on the end face of each of the flat tubes on each of the narrow sides and spaced from the formation, wherein each of the flat tubes has a solder dam formed on a surface of each of the flat tubes intermediate the end face and in a region of each of the flat tubes that is disposed within the wall when each of the flat tubes is assembled to the header tube, wherein a gap is formed by the first chamfer between each of the flat tubes and the wall of the header tube, and wherein the gap generates a capillary force on a liquid solder during a soldering process militating against blockage of the flow channels of each of the flat tubes.

2. The device according to claim 1, wherein each of the grooves is symmetrical.

3. The device according to claim 1, wherein a height of each of the grooves is the same as a height of each of the openings.

4. The device according to claim 1, wherein ends of the grooves extend at least up to a plane that is spanned by a longitudinal axis of the header tube and parallel to an end face of each of the flat tubes.

5. The device according to claim 1, wherein the first chamfer is formed on an outer side of the header tube.

6. The device according to claim 5, wherein the first chamfer is embodied as having an angle ranging from 15 to 45 with respect to a longitudinal axis of each of the flat tubes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional details, features and advantages of embodiments of the invention are provided in the following description of embodiment examples with reference to the accompanying set of drawings. The drawings show:

(2) FIG. 1a shows a sectional illustration from a top plan view of a prior art device for a heat exchanger for collecting and distributing a heat exchange fluid,

(3) FIG. 1b shows a perspective view of the prior art device for a heat exchanger of FIG. 1a,

(4) FIG. 2a shows a sectional illustration from a top plan view of a device for a heat exchanger for collecting and distributing a heat exchange fluid, having a header tube embodied as integral and a plurality of flat tubes,

(5) FIG. 2b shows a perspective view of the device for a heat exchanger of FIG. 2a, and

(6) FIG. 3 shows an enlarged cross-sectional view of FIG. 2a.

DETAILED DESCRIPTION

(7) FIGS. 2a and 2b each show a device 1 for a heat exchanger for collecting and distributing a heat exchange fluid, having a header tube 2 embodied as integral and a plurality of flat tubes 6. FIG. 2a shows a sectional illustration from a plan view along a longitudinal axis of header tube 2. FIG. 2b shows a perspective view.

(8) The same components of the device 1 are provided with the same reference signs as in FIGS. 1a and 1b.

(9) The flat tubes 6 are likewise embodied as having inner flow channels 7 arranged parallel to one another. The inner flow channels 7 are aligned along a longitudinal axis of the flat tubes 6 and are charged with fluid simultaneously when the heat exchanger is in operation.

(10) The hollow cylindrical header tube 2 has through openings 5 formed in a wall 3 or in the lateral surface, which are aligned with their longitudinal dimension perpendicular to the longitudinal axis of header tube 2 and which serve to receive the flat tubes 6. The cross-section or the cross-sectional area of the through openings 5, which are embodied as elongated openings, corresponds substantially to the outer circumferential shape of the flat tubes 6 plus a tolerance in terms of the circumferential shape of the flat tubes 6 that is necessary for assembly. The circumferential shape refers in this case to a section perpendicular to a longitudinal axis of the flat tubes 6.

(11) When the device 1 is in the assembled state, the ends of the flat tubes 6 are arranged in the through openings 5. The inner volumes of the flow channels 7 of the flat tubes 7 and the inner volume of the header tube 2, which is surrounded and delimited by the wall 3, are thereby interconnected. The ends of the flat tubes 6 project into the free cross-section 4 of the header tube 2.

(12) The flat tubes 6, which have a narrow side and a wide side, are formed as having a width b on the wide side. The header tube 2, which is embodied as a hollow cylinder according to FIGS. 2a and 2b, has a circular free cross-section 4 having an inner diameter d. The free cross-section 4 is enclosed by a circular wall 3 having a wall thickness s, so that an outer diameter D of the header tube 2 is the sum of the inner diameter d plus twice the wall thickness s.

(13) The configuration of the circular cross-section of the header tube 2 allows refrigerant lines to be advantageously connected at any angles.

(14) Alternatively, the cross-section of the header tube 2 can also be embodied as oval or asymmetrical.

(15) The flat tubes 6, which are aligned with their wide sides parallel to one another, are arranged perpendicular to the longitudinal axis of the header tube 2, so that the flat tubes 6 having width b are also arranged parallel to the circular inner cross-section 4 having the inner diameter d as the greatest dimension of inner cross-section 4 perpendicular to the longitudinal axis of the header tube 2.

(16) The flat tubes 6 have widths b which are greater than the inner diameter d of the free cross-section 4, and are smaller than outer diameter D of header tube 2. Since the flat tubes 6 are also aligned with their wide sides centered in relation to the longitudinal axis of the header tube 2, the through openings 5 project with their narrow sides at both ends beyond the free cross-section 4 and into the wall 3 of the header tube 2. The through openings 5 are thus introduced into the wall 3 of the header tube 2, in particular punched or milled, in such a way that the boundaries of the through openings 5 at the narrow sides end within the core material of the header tube 2.

(17) Thus during the production of the elongated opening-type or slot-type through openings 5, the wall 3 of the header tube 2 is penetrated in such a way that the through openings 5 for the flat tubes 6 extend from the outer side of the wall 3 up to the free cross-section 4 of the header tube 2 and beyond, into the wall 3.

(18) The flat tubes 6, which are inserted into the through openings 5 through the wall 3 when the device 1 is in the assembled state, are arranged up to their ends, particularly at their narrow sides, within the wall 3. The ends of the through openings 5 within the wall 3 can be used during the process of assembling device 1 as a stop for the insertion of the flat tubes 6 into the header tube 2.

(19) As compared with the known prior art device 1 according to FIGS. 1a and 1b, which is configured for a required burst pressure of 340 bar, with a width b of the flat tubes 6 of 12.0 mm and a header tube 2 having an inner diameter d that is 1.5 mm smaller than width b of flat tubes 6, and a wall thickness s ranging from 2.0 mm to 2.5 mm, for example, the device 1 has an outer diameter ranging from 14.5 mm to 15.5 mm. In contrast, the known prior art device 1 would have to be formed with a wall thickness s ranging from 3.0 mm to 4.0 mm and an outer diameter D ranging from 19.0 mm to 21.0 mm.

(20) Thus the inner diameter d of the header tube 2, which is smaller than is known from the prior art due to the arrangement of the ends of the flat tubes 6 having the narrow sides within wall 3 and therefore in the core material of the header tube 2, results in a smaller wall thickness s with the same pressure tightness.

(21) In addition, with the decreased inner diameter d of the header tube 2, the inner volume of the heat exchanger and therefore the volume of refrigerant in the refrigeration circuit is reduced. As a result, the volume of refrigerant held in reserve or the refrigerant reservoir in the system is decreased.

(22) Moreover, the decreased inner diameter d enables the advantageous use of a less sturdy aluminum, which in turn has an advantageous impact on the production of the device 1, in particular on the punching of the through openings 5, and therefore also on production costs.

(23) In addition, with the narrower wall thickness s, the header tube 2 can also be produced in a single process step as a welded tube having an outer soldered coating. In comparison, it is known that header tubes that have greater wall thicknesses s must be produced with a greater outer diameter D and drawn to a smaller measurement in a subsequent process step.

(24) FIG. 3 shows the device 1 for a heat exchanger for collecting and distributing a heat exchange fluid, having the header tube 2 embodied as integral and a plurality of the flat tubes 6 according to the cross-section shown in FIG. 2a, in an enlarged view.

(25) The through opening 5, embodied as an elongated opening, has a chamfer 8 on the header tube 2. The chamfer 8 serves both as a mounting aid for inserting the flat tube 6 through the wall 3 and as a solder barrier during the process of connecting the header tube 2 to the flat tube 6 by soldering. The gap that is formed by the chamfer 8 between the flat tube 6 and the wall 3 of the header tube 2 generates a capillary force on the liquid solder during the soldering process, thereby preventing any blockage of the flow channels 7 of the flat tube 6.

(26) The chamfer 8 is embodied as having an angle ranging from 15 to 45 with respect to the longitudinal axis of the flat tube 6.

(27) The formation of the through opening 5 extends within the wall 3, preferably up to a plane spanned by the longitudinal axis of header tube 2, parallel to an end face of the flat tubes 6, and thus not simply through the wall 3. For receiving the flat tube 6 in the wall 3, a groove 5 that continues the through opening 5 in the interior of the header tube 2 is formed, which has the same height as the through opening 5. During the assembly of the device 1, the flat tube 6 is not inserted up to the end of the groove 5 into header tube 2, so that between the end of the flat tube 6, in particular the regions of the end face, and the end of the groove 5, an open region, or a formation 9 in the form of a notch remains. The formation 9 generates additional capillary force during the soldering process, which goes beyond the end of the flat tube 6 inserted into header tube 2.

(28) The capillary force acts on the liquid solder, thereby preventing a blockage of the flow channels 7 of the flat tube 6, since the solder is drawn into the formation 9.

(29) To further increase the open area between the ends of the flat tube 6, in particular the areas of the end face, and the end of the groove 5, and therefore the formation 9, and thereby increase the additional capillary force, flat tube 6 is formed on the narrow sides of its end face with a chamfer 10. The region that increases, by means of the chamfer 10, the formation 9 between the end of the flat tube 6, in particular the regions of the narrow side thereof, and the end of the groove 5, generates a further added capillary force on the liquid solder during the soldering process to prevent any blockage of the flow channels 7 of the flat tube 6 and to collect liquid solder.

(30) The flat tube 6 also has an additional solder dam 11 in the form of a notch or groove 5 having a width ranging from 0.1 mm to 0.3 mm and a depth ranging from 0.05 mm to 0.20 mm. The solder dam 11 is formed between the end face of the flat tube 6 and the region of the surface of the flat tube 6 that is located within the wall 3 when the device 1 is in the assembled state. The solder dam 11 is aligned parallel to the end face or perpendicular to the longitudinal axis of the flat tube 6 and therefore perpendicular to the direction of the flow channels 7, and extends at least on the wide sides or around an entire circumference of the flat tube 6.

(31) During the soldering process, the solder dam 11 prevents liquid solder from flowing from the wall 3 toward the end face of the flat tube 6 and therefore likewise prevents any blockage of the flow channels 7.

LIST OF REFERENCE SIGNS

(32) 1, 1 device 2 header tube 3 wall of header tube 2 4 inner/free cross-section of header tube 2 5 groove 5 through opening 6 flat tube 7 flow channel 8 chamfer 9 formation within wall 3 10 chamfer of flat tube 6 11, 11 solder dam D, D outer dimension, outer diameter of header tube 2 d, d inner dimension, inner diameter of header tube 2 b, b width of flat tube 6 s, s wall thickness of flat tube 6 angle of chamfer 8