GB1593657A

GB1593657A - Apparatus for use in the manufacture of a heat exchanger core

Info

Publication number: GB1593657A
Application number: GB1892580A
Authority: GB
Original assignee: Chausson Usines SA
Current assignee: Chausson Usines SA
Priority date: 1976-10-28
Filing date: 1977-10-28
Publication date: 1981-07-22
Also published as: ES463597A1; FR2369033B1; FR2369033A1; IT1087270B; DE2747782C2; BE860018A; ES463596A1; DE2747782A1; GB1593656A

Description

PATENT SPECIFICATION

Application No 18925/80 Divided out of No 1 593 656 Convention Application No.

7632612 ( 11) 1 593 657 ( 22) Filed 28 Oct 1977 ( 32) Filed 28 Oct 1976 in France (FR) Complete Specification published 22 July 1981

INT CL 3 B 21 D 39/08 39/06 Index at acceptance B 3 J 15 ( 54) IMPROVEMENTS IN OR RELATING TO APPARATUS FOR USE IN THE MANUFACTURE OF A HEAT EXCHANGER CORE ( 71) We, SOCIETE ANONYME DES USINES CHAUSSON, a company duly organised under the laws of France, of 35, rue Malakoff, 92 Asnieres, France, do hereby declare the invention for which we pray that a patient may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement:-

This invention relates to an apparatus for use in the manufacture of a heat exchanger core which comprises tubes inserted through fins and in tube passages of tube end plates.

According to the present invention, there is provided an apparatus for use in the manufacture of a heat exchanger core which comprises tubes inserted through fins and in tube passages ot tube end plates, the apparatus comprising push rods carried by a movable plate, each push rod having at a free end thereof a tool for expanding an associated tube by distortion, each tool having an axial groove and means to locate a longitudinal bead protruding axially along the inside of the tube, whereby the bead is guided into said groove upon motion of the tool to cause the expansion of the tube.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:Figure 1 is a diagrammatic cross-sectional elevation of a radiator core and of part of an apparatus for use in the manufacture of the core, Figure 2 is a diagrammatic, partly exploded, perspective view illustrating different operations for the manufacture of a tube in the radiator core of Figure 1, Figure 3 is an elevation of one form of a tool of the apparatus and shows how the tool is used to expand a tube mouth, Figure 4 is an elevation similar to Figure 3 but rotated by 900, Figure 5 is a diagrammatic elevation, partly in section, illustrating a particular feature of the apparatus; Figure 6 is a view similar to Figure 5, showing a possible variation in the particular feature illustrated in that Figure, Figure 7 is an enlarged lateral elevation of another form of the tool shown in Figures 3 and 4, Figure 8 is an end elevation seen according 55 to the line VIII-VIII in Figure 7, and Figure 9 is a cross-sectional elevation similar to Figure 4 and shows yet another form of the tool.

Referring to the drawings, Figure 1 diag 60 rammatically shows a core of a cooling radiator, which core is constituted by tubes 1 engaged in perforated apertures 2 a of cooling fins 2 The tubes 1 are also engaged in tue passages 3 a of tube end plates 3 and 3 i, 65 respectively.

The tubes 1 are tubes with a circular cross-section of the type called electrowelded tubes, i e tubes which, as illustrated in Figure 2, are made by progressive rolling 70 up of a strip forming a preliminary tubular shape 4, bringing together edges 5, 5 a of the strip so rolled, then holding the edges 5, 5 a close together or even tight against one another and passing a welding element con 75 stituted, in the example shown, by a coil 6 supplied with a high frequency current which heats the edges 5, 5 a; rollers (not shown) then ensure the forging and thus the welding of the edges 5, 5 a 80 The type of tube 1 so constructed is formed at the moment the edges 5, 5 a are welded with an outer longitudinal bead 7 and an inner longitudinal bead 8 right along the welded edges 85 In order that the outer wall of the tube is made smooth and accurately dimensioned the outer bead 7 is removed with a cutting tool 7 a (Figure 2) which is normally provided on the machine forming and welding the 90 tube Taking into consideration the small diameter of the tubes used in heat exchanges, particularly cooling radiators, the diameter of each tube being of about 5 mm, it is not possible to remove the inner bead 8 on the 95 machine manufacturing the tube.

The tubes 1 manufactured as above explained are, after they have been positioned in the fins 2 and end plates 3, 3 i, submitted to a physical expansion operation 100 ( 21) ( 62) ( 31) ( 33) ( 44) ( 51) ( 52) ( 19 1 593 657 performed by expansion tools 9 mounted at the ends of push rods 10 protruding from a plate 11 which can be moved in the direction of the arrow ft so that the tools 9 will be progressively inserted into the tubes 1 to produce a radial pressure which causes their expansion by plastic deformation which occurs when the resilient limit of the metal constituting the tubes is exceeded These tubes are then permanently distorted while they are strongly pressed against the walls of the apertures 2 a of the fins and against the walls of the tube passages 3 a in the end plates 3 and 3 i, respectively This obviates the need for welding of the tubes to the fins and end plates.

To prevent any motion of each tube 1 during insertion of the tools 9, the end la of each tube 1 is for example held to rest in the base of a respective recess 12, the recesses 12 being provided in a bearing plate 13 The tools 9 are inserted into the tubes 1 for example for at least half of their length and then they are removed The radiator core is then rotated by 180 , and the tools 9 are re-inserted into the tubes 1, but from their other ends la Other working methods can be envisaged.

To take into account the existence of the inner bead 8, the tools 9 carried by the rods are each constituted for example as illustrated in Figure 3 and 4 As shown, the expansion tool comprises a core 14, for example of circular cross-section, but whose diameter is substantially smaller than that of the duct formed by each tube 1 in such a way that the core 14 can freely enter inside the tube whatever size the bead 8 may be.

The core 14 is connected to a corresponding push rod 10 which delimits, in the embodiment shown in Figure 3 and 4, a shoulder 15 at its lower end.

The core 14 is used as a support and a guide for a sheat 16 whose lower portion 16 a is of a circular cross-section but is bevelled as illustrated at 17 in such a way that the lower end of the portion 16 a is reduced to a rounded line or rib 16 i The diameter of the portion 16 a is slightly smaller than the inner diameter of the tube 1, for example from 1 to 3 Aoth millimeters, in order that the portion 16 a can freely enter the tube 1 when moved in the direction of the arrow ft The portion 16 a extends from the rib 16, beyond the end of the bevelled portion which, preferably, forms two helica ramps 171, 172.

The sheath forms a second portion 16 b which is bulbous and whose maximum diameter corresponds to the internal diameter to which each tube has to be expanded.

The second portion 16 b has an axial groove 18 whose depth is at least equal to the thickness of the bead 8, and the groove 18 extends down as far as the top of the bevelled portion 17 and over the whole length of the portion 16 b.

The sheath 16 is preferably fixed onto the core 14 which is inserted in the rod 10 so that the sheath 16 will bear against the shoulder In order that the core 14 and the sheath 70 16 be axially connected to the rod 10 while being able to rotate relatively to the rod 10, there is provided a retaining ring or any other equivalent means 19 It is important that the unit formed by the core 14 and the sheath 16 75 can freely rotate.

As illustrated in the drawings and particularly in Figures 3, 4 and 5, when the plate 11 is moved in the direction of the arrowfi, the tools 9 are progressively brought to the level 80 of the upper mouth of each the tube 1 and, consequently, it is the rounded rim 16, of the sheath 16 which first enters the corresponding tube 1 If this end rim 16 meets the bead 8, it is deviated and turned by the bead 8 85 which thus comes progressively into abutment with one of the ramps 17, or 172 of the bevelled portion 17 It results therefrom that the sheath 16 and the core 14 are progressively rotated up to the moment when the 90 groove 18 is aligned with the bead 8 The motion according to arrow f continuing, the bead 8 is used as a guide for the sheath 16 which cannot rotate any longer and whose portion 16 b causes the progressive expan 95 sion by plastic deformation of the tube 1.

The above disclosure shows that the initial angular position of the bead 8 with respect to the linear end 16, of the sheath has no detrimental influence Actually there is no differ 100 ence whether the bead will initially come into abutment with a part of the ramp 171 or 172 or whether the rim will directly enter the groove 18 without having ever been in contact with the ramps 105 From the above, it can be seen that no particular care need to be taken at the moment of positioning the tubes 1 into the fins 2 and possibly into the end plates 3, 3 i.

Fig 6 shows a slight variation according to 110 which the expansion tools 9, having the basis form as above described, are fixedly mounted at the end of the push rods 10, i e.

without having the possibility to rotate with respect to the rods In this case, the rods 10 115 themselves are able to rotate with respect to the plate 11 and, for this purpose, housings are for example provided in the plate 11, the housings 20 containing a ball 21 or other low friction abutment element provided to 120 transmit the push of the plate 11 to the rods A retaining component, for example a ring 22, is provided in order that each rod 10 will be held in the plate 11.

Figures 7 and 8 illustrate a variation of an 125 embodiment of the sheath 16 mounted on the core 14 According to this variation, the sheath 16 is provided at its periphery with ribs 23 with a circular generatrix, these ribs forming grooves 18 i, 182 18 therebet 130 1 593 657 ween.

Figure 7 shows that the above mentioned ribs and grooves extend over the whole length of a portion 16 b of the sheath and are then extended along the periphery of a portion 16 a which is shaped as a truncated cone.

Also, the ribs 23 are progressively made thinner to form a rib linear edge or rib 24 at their ends.

In this case, upon the motion in the direction of the arrow fi which is given to each expansion tool, inner bead 8 of a tube 1 is automatically guided into one of the grooves 18 i, 182 or 18, the bead 8 causing the sheath to rotate as above explained or causing both the sheath and the rod carrying it to rotate.

Fig 9 shows another variation in which the same reference numbers designate the same parts as in Figures 3 and 4 As illustrated, a section 16 c called a guiding section and having a circular cross-section is provided between the portions 16 a and 16 b The portion 16 a is bevelled to form the same ramps 17 as in Figs 3 and 4, and these ramps lead as previously to the groove 18 which also extends in the guiding section 16 c in forming a slot The radius of the guiding section 16 c is the same as that of the portion 16 a, that is just a very little smaller than the inner diameter of the tube 1, or even equal to this diameter before expansion of the tube.

The upper portion of the groove 18 is closed by a cutting edge 25 which extends transversely to the groove 18 substantially at the level of the intersection of the guiding section 16 a and of the bulbous portion 16 b.

The cutting portion 25 a of the cutting edge is aligned with the periphery of the guding section 16 a.

When the cutting tool as above described is introduced into the tube 1, inner bead 8 engages one of the ramps of the bevelled portion 17, which causes the expansion tool to rotate in either direction to bring the tool into an angular position at which the bead 8 of the tube 1 always enters the groove 18.

When the guiding section 16 c enters the tube 1, it bears on the inner wall of this tube by its whole periphery which ensures a perfect centering of the tool inside the tube before the cutting device 25 a of the cutting edge 25 reaches the bead 8 Then the cutting device 25 cuts off the bead 8 to level the corresponding portion, the tool continuing to be suitably centered by the guiding section 16 c The portion 16 b produces its expanding effect on the smoothed-off portion of the tube, which means on the whole inner periphery, thus the expansion is then carried out exactly as it is done for a tube which has been obtained by a drawing out technique.

It is advantageous, as shown in Figure 9, that the core 14 be foreshortened to extend only as far as 14 a, i e at the level of the cutting edge 25 Thus the portion 16 a is hollow which enables the chips and swarf coming from the cutting of the bead 8 to fall inside the tube 1 as the tool advances without the chips etc fouling the tool.

It will be appreciated that the core 14 and 70 the sheath 16 can be constituted by only a single part.

ft will be further appreciated that, with the present apparatus, it becomes possible to manufacture heat exchangers while using 75 tubes of a cheaper construction, especially electrically-welded tubes which up to now could not be used in conjunction with expansion of the tube mouths as described because of the presence of the longitudinal beading 80 The present apparatus is also shown and described in co-pending Application No.

45094/77 (Serial No 1 593 656) to which reference is accordingly directed.

Claims

WHAT WE CLAIM IS 85

1 An apparatus for use in the manufacture of a heat exchanger core which comprises tubes inserted through fins and in tube passages of tube end plates, the apparatus comprising push rods carried by a movable 90 plate, each push rod having at a free end thereof a tool for expanding an associated tube by distortion, each tool having an axial groove and means to locate a longitudinal bead protruding along the inside of the tube, 95 whereby the bead is guided into said groove upon motion of the tool to cause the expansion of the tube.

2 An apparatus as claimed in claim 1, wherein a cutting edge is provided in said 100 groove and is positioned upstream, having regard to the intended direction of motion of said tool in use, of a part of said tool that is intended for expanding a said associated tube 105

3 An apparatus as claimed in claim 1 or 2, wherein said tool is mounted in such a way that it can rotate relatively to the push-rod which carries it.

4 An apparatus as claimed in claim 1, 2 110 or 3, wherein each push rod is rotatably mounted in said movable plate.

An apparatus as claimed in any one of the preceding claims, wherein each said tool comprises a sheath extending axially of its 115 associated push rod, said sheath defining a first portion of a diameter substantially equal to that of the tube before expansion thereof and a second portion of a diameter which corresponds to the internal diameter to 120 which the tube is to be expanded, said groove being provided in said second portion and the edges of said groove being extended by ramps which define a bevelled cut in said first portion, the ramps each terminating in an 125 edge which is so shaped to comprise said means to locate a said longitudinal bead of a said tube.

6 An apparatus as claimed in any one of the preceding claims, wherein a portion or 130 1 593 657 said second portion of said tool has a bulbous shape.

7 An apparatus as claimed in claim 5 or claims 5 and 6, wherein said groove extends over the whole of said second portion of the tool.

8 An apparatus as claimed in claims 2 and 5, or claim 6 or 7 as appendant to claims 2 and 5, wherein a guiding section of circular cross section is provided between said first and second portions of the tool, the diameter of the guiding section corresponding to the inner diameter of the tube to be expanded and said cutting edge being provided in said guiding section.

9 An apparatus as claimed in claim 5 or any one of claims 6 to 8 as appendant to claim 5, wherein at least said first portion is hollow and communicates with said groove to form a slot.

An apparatus as claimed in any one of the preceding claims, wherein said tool has a plurality of said grooves which are formed between ribs, said grooves becoming thinner towards a free end of said tool and terminat 25 ing to form a substantially linear edge at the free end of the tool.

11 An apparatus for use in the manufacture of a heat exchanger core which comprises tubes inserted through fins and in tube 30 passages of tube end plates, substantially as hereinbefore described with reference to any one of the embodiments shown in the accompanying drawings.

HASELTINE, LAKE & CO, Chartered Patent Agents.

Hazlitt House, 28 Southampton Buildings, Chancery Lane, London WC 2 A IAT -alsoTemple Gate House, Temple Gate, Bristol B 81 8 PT -and9 Park Square, Leeds LSI 2 LH, York Agents for the Applicants.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd Berwick-upon-Tweed, 1981 Published at the Patent Office 25 Southampton Buildings London, WC 2 A l AY, from which copies may be obtained.