IL21598A - A fin plate for tube and plate fin radiator cores - Google Patents

Description

For many vyears past, radiator cores have been made comprising tubes which are engaged in a set of fins respectively placed, at regialar intervals which must be determined with a relatively close accuracy so that the heat exchange takes place in good conditions. In certain cases, for determining the pitch of fins, i.e., the spac~e separating successive fins, lugs or points also called spacers are made in them between the' tube passage openings that they possess, projectin to an extent which corresponds to said space to be obtained. This arrangement is satisfactory in certain cases, more particularly when the tubes are relatively spaced out between them and when the fins are sufficiently thick so that they do not risk bending arid being distorted at the moment when the tubes are engaged in the openings between the flange or collar provided to receive them; in most cases, however, these spacers have well-known disadvantages, more particularly, their influence is unfavourable as the part of the fin forming the spacer has, starting from the wall of the tube which diffuses the heat, a length greater than the half-distance between two consecutive tubes < This means that the efficiency of this part of the fin, i.e., in other words its mean temperature, fall below- the efficiency of a similar fin not comprising a spacer* This lowering of efficiency is the more important seeing that the spacing of the fins is greater and that the metal of the fin is not such a good. heat conductor, which is the case of fins made of steel" generally used on radiator cores -of motor vehicles manufactured by mass production. It has been proposed, for obviating this disadvantage, to suppress, the spacers by a mutual strutting of fins by means uf cambered lugs formed crosswise to the collar bordering the passage openings of tubes, i.e., formed at t-he front and rear parts of said tubes. This embodiment has given allowing for the progress |ia e in the technique of cooling radiators, for the tubes now employed are very thin ones, whose- thickness is in the region of 2 mm. , and consequently, the known lug or tongue formed crosswise to the collar of the tube passages in the fins, a -lug whose width is necessarily smaller than that of said passage, can no longer have sufficient mechanical strength for ensuring the regular strutting of fins at the moment when they are positioned by inserting the tubes. Actually, seeing that the tubes passage has a width of about 2 mm., the upper end of the tongues or lugs that are known would have a lesser width, of about one millimetre, and it is obvious for anyone experienced in this tenhnique that said, lugs or tongues have thus practically no strength, and in any case, much less than the stresses that they should bear when the tubes are engaged in the bundle of fins.

The present invention obviates this disadvantage by creating a new fin fcr tube and plate fin cores and a method for the manufacturing of said fin.

According to the invention, the fin plate has a number of passage openings for tubes corresponding to the number of tubes that this core must comprise, these openings being also made in positions ^aietf corresponding to the arrangement that said tubes must occupy, and each opening of general rectangular shape with rounded ends is bordered on each of its large sides by rectangular collars extending at right angles in relation to the plane of the fin, one at least of the collars being integral with a spacer extending in the prolongation of said collar and whose length is equal to the spacing there must be between the fins of the assembled core, whereas its width is determined by the stress to be borne.

Various other characteristics of the invention will " Forms Pig. 2 is a partial plane view, on a ls.rger scale, of a fin showing a manufacturing stage.

Fig. 3 is a plane view corresponding to fig. 2, showing another manufacturing stage.

Fig. 4 is a section taken along the line IV-IV of fig- 3. plane Fig. 5 is a partial/view on a smaller scale, of a fin showing a supplementary detail.

Figs. 6 and 7 are plane views respectively corresponding to figs. 2 and 3 and showing a slight modification.

Figs. .8 and 9 are plane views similar to figs. 6 and 7 of another modification.

Figs. 10 and 11 are similar plane views to those of the preceding figures and illustrating an alternative.

Fig . 12 is a section seen along the line XII-XII of fig. 11.

Fig. 13 is an elevation of part of a radiator core seen along the line XIII-XIII of fig. 11.

Fig. 14 is a partial' plane view seen from above of a fin according to the present invention.

Fig. 15 is a section taken along the line XV-XV of fig. 14.

Fig. 16 is a section taken along the line XVI-XVI of fig. 14.

Fig. 1 shows diagrammatically a radiator core which comprises tubes 1 for the circulation of a cooling liquid, these tubes 1 being thermically connected together by fins 2 the spacing of which is constant and determined by spacers to modify the particular structure of the fins in their parts located between the successive tubes 1 so that said parts called intermediate of the fins can be variously shaped for improving their thermic efficiency as stated in that which follows* According to the invention, for making the struts or spacers that must define the spacing of the fins, i.e., their respective distance apart, one proceeds as follows : In fig. 2, each of the fins is subjected to a cutting operation which is made at the place that the tubes must subsequently occupy, this cut having a rectilinear segment 3 whose ends are joined to two opposite cuts 4, 5 made along the three sides of a rectangle, these cuts, called rectangular cuts, being themselves prolonged by curved cuts 6. The number of cuts made in each fin corresponds to the number of tubes which must pass through said fins. After the cutting operation, a cambering operation is carried out which has the effect of raising the two edges defined by the cut 3 on one side of the fin. Slots 7 are thus made of general rectangular shape .bordered on each of their two' large sides by collars .8, 9 whose height corresponds to half the width of the slot - 7, ..the two collars 8, 9 being respectively prolonged by projecting spacers 10 and 11 which have been defined by the opposite rectangul-ar- cuts 4, 5 and whose height corresponds to the spacing thatthe fins must have between them. As will be seen in fig. 3, the curved cuts 6 have the effect of providing in the fins 2 solid parts 12 which are below the spacers 10 and 11, when the latter are raised after the cambering operation, these solid parts thus forming bearing points for the spacers 10, 11 of the contiguous fin, so that there is no risk of a spacer can be penetrated into the slots of another fin..

The spacers or strutted lugs being placed at the two being integral with the collars 8, 9 in which the tubes are tightened, said lugs are thus placed at least partly against the tubes, so that their resistance to singeing or flexure is good even when the fins are very thin and made of relatively soft metal like copper or aluminium. Moreover, the spacers 10, 11 being arranged in a contiguous position in relation to the tubes, it results, at the moment when the latter are engaged in a bundle of fins for making up the core of fig. 1, that the intermediate parts of said fins, i.e., the parts extending between two consecutive tubes, do not run the risk of bending, and also these parts are left completely free, which enables them to be shaped, for example, as shown at 13 in fig. 5, so as to increase their heat yield, more particularly by folding them or by providing shutters or slits, which ensures a better evacuation of the calories that said fins must dissipate.

The" method of embodiment according to figs. 2 to 4 requires that the spacing of the fins be greater than the thickness of the tubes of the core. When this spacing, on the contrary, is smaller or equal to the thickness of the tubes of the core, one proceeds as shown in figs. 6 and 7, or in figs. 8 and 9· According to figs..6 and 7, the cuts 4 are made and' a first fold is made along the line 14 so- as to define a shoe 15 at the ends of the spacers 11, intended to make a bearing surface for the contiguous fin, and in this way the spacer 11 is shorter and can have any required height.

According to figs. 8 and. 9, a semi-rectangular section 4a is made at the end of the cut rectilinear section 3, and the curved cut 6 is prolonged by a rectilinear section 6a extending as far as the place that the opposite collar must occupy - in this case, the collar 8 - after the latter has been raised by the cambering operation. Thus, a spacer 11a is In the foregoing it has been shown how the rigid spacers could be formed at the ends of the passages of tubes defined by the slots 7. These spacers can be formed in any similar manner in other spo'ts and more particularly figs. 10 to 13 show that said spacer can, according to the invention, also project from any part of the collars 8, 9· In this case, two sections of aligned cuts 3a, 3b are made in the fins, separated by a cut segment 16 in saw teeth defining, on either side of the cut segments 3a, 3b, two triangles 17, 18 oppo- sed by the summit. Also, lacing cuts 19 and 20 are symmetrically made at the end of the segments 3a, 3b as in the preceding examples; after making the above-mentioned cuts, a cambering operation is proceeded with for straightening the collars 8, 9 which at the same time causes that of the iriangles 17, 18, which, at that moment, form spacers. Sc that said spacers cannot engaged in the slots 7 of the contiguous fin and to be able to regulate at will the spacing of the fins in the core, a complementary operation consists of folding back the end of the triangular lugs 17, 18 to form bearing shoes 21 whose position is clearly shown in fig. 13 v/hen the radiator core is mounted. In this method of execution, the lacing lug cuts 19, 20 define, after the cambering operation ensuring the raising of the collars 8, 9, two tapered sectors 22, 23 at the end of the tube passage 7, these tapered sectors formed by the fins ensuring, on the one hand, the proper centering of the tubes 1, and on the other hand, an improved thermal link between said tubes and said fins.

As in the preceding examples, we see that the embodiment according to figs. 10 to 13 by no means affects the inter-mediate part of the fins between the consecutive tubes, and consequently, these parts can be shaped at request and more articularl as stated previously with reference to fig. 5.

According to figs. 14 to 16, the operation for cambering the collars 8, 9 and lugs 10 and 11, and shaping the spacers, is carried out so that these lugs 10, 11 do not-extend parallel to the tubes 1 , but separate each tube according to an angle of about 10°, for example. This arrangement is particularly well shown in fig. 15· Also, as shown in fig. 14, the lugs 1Q, 11 are, over the greater part of their extend, slightly arched so as to increase their rigidity.

Seeing that the spacers 10 and 11 diverge from the wall of the corresponding- tube, they do not risk penetrating between this tube and the edge of the slot 7 of the immediately contiguous fin. For the same reason, it has been found advantageous also to provide an alternation in the arrangement of the lugs 10, 11. Actually, as shown more particularly in fig. 14, the lugs 10 are raised towards the right of each slot 7 whereas the lugs 11 are raised to the left of these slots · Moreover, two successive slots of the same fin have their lugs 10 and 11 which are alternated so that when n fins are piled one on the other, each spacer 10 is underneath a spacer 10, whereas each spacer 11 is underneath a spacer 11, as shown in figs . 15 and 16.

. This arrangement, associated with the arching of the lugs 10, 11, means that a continuity is obtained in assembling fins, for this arch imparted to spacers, in addition to increasing their rigidity, provides a wider contact surface for these spacers with the upper fin.

The part of the fins between successive collars 9, 8 is cut to provide points defining shutters 25 all identical to each other. The successive groups of shutters are nevertheless offset, as shown in fig. 1¾ in the flow direction of the that the fin retains a sufficient solidity and that throttling zones are hot created for the passage of calories, but that, on the contrary, thermal diffusion can take place in as homogeneous a manner as possible in all parts of the fin.

When the radiator core comprises, as is nearly always the case, several successive rows of tubes - in the example shown, two rows - the incidence of the shutters 9 of group a (fig. 16) is opposed to the incidence of the shutters 9 of group b, so that the course of the air passing through the shutters is appreciably that shown by the arrow f .

To still further improve the thermal efficiency of the fin and also to increase the rigidity of the edges of each fin, small stampings or bosses 26 (fig. 14) are made on the front and rear- edges of each fin, in the direction of the air flow, these stampings being fairly close together; for example, a stamping is provided in front of each tube and a stamping in front of each group of shutters.

In order to differentiate the front from the rear edge of the fin, for the purpose more particularly of facilitating manufacture to be able easily to locate the position that the in fi:ab must occupy during their assembling/bundles before puttin the tubes in place, it is advantageous that the front edge, for example, of the fin should not have the same series of stampings 26, more particularly one stamping in ten can be suppressed on the front edge, as shown at the bottom part of fig. H.

The fins being made from very thin strips, it is of course important that they have a sufficient rigidity so that they are not distorted at the moment when the core is made up. For this, there is made in each fin, between two successive rows of slots for receiving the tubes 1 , a shallow longitudinal moulding 27, so as not to interfere with the air flow; by way of exam le this mouldin can have a width of about 2 mm,., and made on the strip, during the work, which must form each fin in the first shaping operation, so that this moulding acts for guiding the strip under the wor ng tools which must then effect the cuts and cambers leading to the forming of the collars, spacers and shutters.

Although from the purely thermal point of view, it is not greatly important that the projections made by the collars, 8, 9, the spacers 10, 11 and the- shutters 25 be directed on one or the other side of the plane defined by each fin, it is advantageous from the manufacturing standpoint, and this is another characteristic of the invention, that all these pro sections be formed on the same side of the plane defined by the fin, for, thus it is possible to obtain an easy sliding of the fin on the shaping tool or tools, which would not be the case if the shutters were cut and cambered on one of the sides of the fin, whereas the collars and spacers would be cut on the other side of the fin.

The invention is not restricted to the examples of embodiment shown and described in detail, for various modifi-cations can be applied to it without going outside of its scope.

Claims (18)

1. HAVING HOW particularly described and ascertained the nature of our said invention and in what manner the same ia to be performed, we declare that what we claim iss- 1. Met od for manufacturing a radiator core comprising a plurality of tubes and fins, said tubes being spaced apart by regular, constant amounts by means of said fins, characterized in that there is formed in each fin at least one rectilinear cut and at least one further out combined with said rectilinear cut having a geometrical, e.g. triangular, rectangular, etc, shape, the cut sonea of each fin being then subjected to at least one cambering operation resulting in the raising on one of the faces of the fin of two collars bordering the opening formed by this eambering operation and simultaneously, the raising of at least one spacer defined by said further cut, this spacer thus extending in a position in which it is adapted to be contiguous to the tubes of the core, then engaged in an opening provided, whereas the fin zone extending between two consecutive tubes is not affected by the shape of said spacer.

2. Kethod according to Claim 1, characterised in that the cambering of the spacers is effected so that these spacers are sloped to an extent exceeding 90°, so that they diverge in relation to the direction of the wall of the tubes when the latter are positioned, these spacers being also arched.

3. Fin plate for cooling a radiator core, characterized in that it has a number of passage openings or tubes corresponding to the number of tubes that this eore must comprise, these openings being also made in positions corresponding to the arrangement that said tubes must occupy, and each opening of general rectangular shape with rounded ends is bordered on each of its large sides by rectangular collars extending at right angle in relation to the plane of the fin, one at least of the collars being integral with a spacer extending in the prolongation of said collar and whose length is equal to the spacing there must be between the fins of the assembled core, whereas its width is determined by the stress to be borne.

4. Fin plate according to Claim 3» characterized in that each of the two collars bordering each tube opening made in each fin comprises a lug.

5. i plate according to Claim 3# characterized in that the spacers are formed at one of the ends of each of the collars and these spacers have a rounded base, so that the projection of said spacers intercepts a solid part of the fin, which forms a bearing surface for the corresponding spacer of the contiguous fin.

6. Fin plate according to Claim 3> characterized in that the upper end of the spacers formed from the collars is bent so as to extend parallel to the plane of the fin thus defining a bearing plate for the contiguous fin.

7. Fin plate according to Claim 3» characterized in that at least one spacer is formed from each collar, appreciably in the middle aone of the latter, thus spacer being defined by a sawtooth cut, made between two aligned rectilinear cut segments from which said collars are formed following the cambering operation.

8. Q. Fin plate according to Claim 3, characterized in that when the spacers are provided in the vicinity of the middle part of the collars and to do this, sawtooth cuts s are made between two aligned rectilinear cut sections, these sections being prolonged by a lacing cut so that after the catabering operation, the fin forms two tapered sectors forming covers for the ends of the tubes engaged in the fins0

9. « Fi plate according to Claim 3, characterized in that the ends of the spacers formed in the vicinity of the middle sone of the collars are turned over to extend parallel to the plane of the fin while forming bearing surfaces for the contiguous fin.

10. i plate according to Claim 3» characterized in that the arrangement of two spacers formed from each cut is alternated by a cut in the other.

11. Fin plate according to Claim 3» characterized in that crosswise cuts are made between the cuts that must define the tube passages and a cambering operation defines sets of shutters from these crosswise cute.

12. Fin plate according to Claim 3» characterized in that the groups of shutters extend between successive collars and are successively offset so that the cut zone for defining said shutters is as extended as possible and that no throttle limiting thermal diffusion is created by said shutters.

13. Pin plate according to Claim 3» characterized in that the front and rear edges of the fin have stampin storming frontage bosses.

14. Fin plate according to Claim 3i characterized in that the frontage stampings made on one and the other edges of the strip forming the fin are shaped according to series that are visually distinct.

15. Fin plate according to Claim 3» characterised in that at leaat one longitudinal moulding is made in the atrip from which the fin is formed for separating the various rows of perforations that the successive rows of circulation tubes must receive.

16. Pin plate according to Claim 3# characterized in that the various projections formed by the moulding, the shutters, the frontage bosses, the collars and the spacers are formed on one side of the strip from which the fin is made.

17. Fin plate according to Claim 3» characterized in that the shutters formed at the level of each row of tube passages are cambered so that their incidence is opposed.

18. Fin plate for tube and plate fins cores and method for manufacturing thereof, substantially as hereinbefore described and illustrated in the accompanying drawings. Dated this 23rd day of June, 1964 For the Applicants