FR2665651A1 - METHOD AND DEVICE FOR PROVIDING THE PARTITION OF A FLUID VEIN. - Google Patents

Abstract

A method is provided for producing a plurality of parallel adjacent channels (15) for splitting a stream of fluid into a plurality of identical component streams. The channels (15) are obtained by simultaneously winding around a single core (1) at least two sheets, namely a first, plane sheet or strip (11) and a second, corrugated sheet (12), said corrugated sheet being inserted between two consecutive turns of the strip (11) so that the highest points (14) of two of its corrugations respectively engage each of said turns. According to the method, the corrugated sheet (12) is stiffened as it is inserted between the turns of the strip (11) by fixing it onto said strip (11) in such a way that the radial spacing between two consecutive turns thereof remains substantially constant.

Description

 The present invention relates to a method and a device intended to ensure the partition of a pipe defining a flow stream of a fluid, into a plurality of elementary streams of identical shape and size and making it possible to promote chemical or physical exchanges between fluids or their various solid or gaseous liquid phases.

 Found in the prior art, and in particular in the field of air conditioning, devices which, to facilitate heat exchange between a stream of flowing air and a source of calories (or frigories), ensure such a partition of a fluid stream by means of a plurality of channels adjacent to that of the flowing air stream.

In a known manner, in particular by the French patent
FR-A-2 625 298 in the name of the Applicant, such channels have been produced by winding on itself a strip, generally metallic, so as to constitute a multiplicity of turns, a corrugated sheet being interposed between these turns, so that the corrugations of said corrugated sheet are parallel to the longitudinal axis of the device, and that the tops of the corrugations are successively in contact with one face and the other of the strip. This gives a plurality of parallel channels whose shape and the dimensions of the section are a function of those of the corrugations of the corrugated sheet, this section usually being of substantially trapezoidal shape, three of the sides of said trapezium being formed by the sides of a corrugation of the corrugated sheet and the fourth side by successively a opposite and the other of the strip.

 It is known that the manufacture of such devices for partitioning a fluid flow stream is particularly delicate when it is desired to produce channels of small cross section and of identical shapes and dimensions.

 Indeed, it is known that the corrugated sheet must have a flexible structure so as to be able to adapt to the variation in radius of curvature to which it is subjected as and when the winding is carried out. However, this same corrugated sheet must be applied to the strip and we are therefore led, during the winding operation, to exert, both on the strip and on the corrugated sheet, a certain tension force tending to tighten the turns. of the two windings.

Because of the flexibility of the corrugated sheets, mentioned above, the latter thus tend to deform, more or less regularly, during said operation, especially as during this latter the distance between a turn during the axis of symmetry of the device gradually increasing, the tension force exerted on the strip sees its torque increase, which thus tends to increase the deformation of the previously formed channels. Experience has thus shown that it was not possible to obtain, by this technique, a plurality of identical adjacent channels covering a flow vein of large diameter, for example of the order of a meter.

 We therefore have recourse to this for other techniques, such as that consisting of purely and simply assembling rigid cylindrical tubes of identical sections which are secured parallel to each other by their generatrices. However, such a form of implementation is particularly difficult, long and costly.

 On the other hand, most of the time, these tubes have a circular section which implies that such a device for partitioning a fluid stream has a significant loss of cross section, corresponding to the surface existing between the tubes.

 The object of the present invention is therefore a method making it possible to obtain, from the winding technique previously mentioned, a bundle of parallel channels of identical sections making it possible to partition fluid streams of large diameter, which is at the times of an easy manufacture and which presents only a minimum loss of passage section.

 On the other hand it was found that the flat sheets available on the market, and used for the manufacture of the corrugated sheet are, for manufacturing reasons, of small width, which leads to limit the length of each of the channels constituting a elementary fluid vein.

The present invention also aims to overcome this drawback by providing a means for producing partitioning devices for fluid veins of practically any length.

 Finally, by the very principle used in this type of device, a repetitive defect or a variation in dimension, even a minimal one, made on a corrugation is multiplied, by the play of successive superpositions of the turns, and leads to substantial deformations which can create , for example, a taper of the device, making it unsuitable for its destination.

 The present invention provides a means for avoiding the superposition of defects and therefore their amplification, thus contributing to a better homogeneity of the flow channels formed.

 The present invention thus relates to a method of manufacturing a plurality of adjacent parallel channels intended to ensure the partitioning of a fluid vein in flow into a plurality of identical elementary veins, the channels being obtained by simultaneous winding, on the same core, of at least two sheets, namely a first flat sheet, or strip, and a second corrugated sheet, the corrugated sheet taking place between two successive turns of the strip so that the vertices of two of its successive corrugations come respectively contact with each of these turns. This process is characterized in that the corrugated sheet is stiffened, as it is placed between the turns of the strip, by fixing it on said strip , so as to maintain substantially constant the radial spacing between two successive turns of the strip.

 The present invention therefore implements two stiffening means, namely a first known means, constituted by the strip and a second means constituted by the corrugated sheet which, as soon as it is fixed to the first means, then behaves as a system of members.

 In addition to the inherent rigidity conferred by the joining of the corrugated element with the strip, the present invention also makes it possible to improve the rigidification provided by the first means since it is possible, without causing the corrugated sheet to be crushed, increase the traction exerted on the strip during winding, which improves the rigidity imparted to the device by the first stiffening means.

 In an advantageous variant of the invention, the corrugated sheet consists of a series of corrugated elements placed end to end, the junction between two successive elements, namely a first element or upstream element (that is to say a element already in place between two turns of the strip) and a second element or downstream element (that is to say an element to be put in place), by fixing these two elements to the strip, and the front part of the downstream element abutting with the rear part of the upstream element so as to ensure the continuity of the undulation between the upstream element and the downstream element.

 In another implementation variant of the invention, the front part of a corrugated element ends in a corrugation vertex intended to come into abutment against a flank of a corrugation situated furthest back from an element arranged upstream, superimposed on the rear part of it. Under these conditions, the length of the rear part of an element situated beyond said flank forming a stop is not critical, and the implementation of an additional length dimension is thus avoided. In addition, in order to simplify the manufacture of the corrugated elements, as well as to favor their placement on an element situated upstream with respect to them, each corrugated element can end in a flat part, extending the most corrugated flank backward.

 In another variant of implementation of the invention, and in order to avoid multiple superimpositions of minimal defects likely to lead, as mentioned above, to significant defects becoming quickly unacceptable, the corrugated sheet consists of a series separate elements placed end to end, each element being reversed laterally with respect to the previous one, so that a given side of an element is opposite this side on the next element.

 Finally, in another variant of implementation of the invention, the inherent rigidity of the corrugated element is improved, which is particularly advantageous in the case of corrugated elements of large width and small thickness, by making end of the latter intended to come into contact with the side of the corrugation of another element, a stiffening rib constituted by a fold substantially parallel to the side of the corrugation with which it is intended to come into contact.

 For certain applications of the device according to the invention, it will be ensured that, without being in complete communication with those which are adjacent thereto, each channel nevertheless communicates with them, so as to ensure a balancing of the flow parameters of the different channels .

 To do this, it is advantageously possible to use a strip made of a porous material, the dimensions of the pores of which will make it possible to adjust, as a function of the specifics of the use, the interchannel exchange rate that one wishes to achieve.

Various embodiments of the present invention will be described below, by way of non-limiting examples, with reference to the appended drawing in which
Figure 1 is a partial perspective view of a device for implementing the method according to the invention, shown during production of the winding.

 Figure 2 is a partial cross section in section, of a device according to the invention, shown at the start of winding embodiment.

 Figure 3 is a partial cross section in section of a device according to the invention shown in the course of the winding.

 Figure 4 is a partial sectional view of several corrugated elements, presented before their installation and substantially in the position they will occupy in the device.

 Figures 5 and 6 are partial cross-sectional views of alternative embodiments of the invention.

 Figure 7 is a partial perspective view of a corrugated element.

 FIG. 8 is a partial view in cross section of the variant embodiment of FIG. 7.

 Figure 9 is a perspective view of an embodiment of the invention.

 In Figure 1 a core 1, consisting of a cylindrical tube is secured, at each of its ends of a hub 3 rotatably mounted on a bearing 5 held by a support 7 (shown partially). In this way the core 1 is able to rotate around the horizontal axis xx 'joining the two bearings 5. Radial spokes 9, serving as winding guides, start from the center of the hub 3 and extend towards the outside of it to come to rest on a wheel (not shown in the drawing).

 Was fixed in known manner, the extreme edges of a flat metal sheet, or strip 11, and a corrugated metal sheet 12 on said core 1 and the device was made to rotate around the axis xx 'in direction C, opposite to that of clockwise. Then, as the corrugated sheet 12 is positioned, two successive turns of the strip 11, are joined together, for example by spot welding 14, produced at each of the ends of the core 1, respectively at S and S ', the corrugated sheet 12 on the strip 11. This gives a series of channels 15.

 This proceeds to the progressive securing of the corrugated element 12 with the strip 11 of, either all of the vertices 13 of the corrugations, or only a part thereof. The number of fixing points will depend on the one hand on the rigidity that one wishes to obtain, rigidity which is also a function of the cross section of the channels 15, of the thickness of the corrugated sheet 12, of its nature, of its method of attachment etc ...

 It will thus be possible to attach, to the strip 11, only one corrugation vertex 13 out of two, or to fix only the vertices 13 in contact with the front or back of the strip 11.

 We can also proceed to the fixing operation of the corrugated sheet 12 on the strip 11, after a complete turn has been carried out, in order to allow a release of the stresses which may exist between the different channels of the same turn and a distribution of these over the entire turn. This improves on the one hand the quality of the fixing since it is carried out without any constraint and on the other hand the regularity of the channels formed.

 As shown in FIG. 2, the fixing can be carried out by spot welding, which has the advantage of being unable to create additional volume inside the channels 15, a volume which would be a source of flow disturbances.

 As shown in FIG. 3, the stiffening of the corrugated sheet 12 can, for certain corrugations, be obtained by making a joining, of a corrugation top 13 in contact with one face of the strip 11, of the latter, and of a wavy top 13 substantially symmetrical to the previous one with respect to the strip 11.

 The corrugated sheet 12, as shown in FIG. 4, can also consist of a series of corrugated elements 12 'which are placed end to end. Each of these corrugated elements 12 ′ is fixed by its corrugation vertices 13 to the strip 11. The corrugated elements 12 ′ can terminate, at each of their ends by a semi-corrugation vertex (Fig. 5) open towards said regions ends, so that bringing the rear face of an element into abutment with the front face of another element ensures continuity of the undulation between the two corrugated elements 12 ′. Preferably, and as shown in FIG. 5, the respective end portions 22 and 23 of the corrugated elements are fixed by respective weld points 14a and 14b on the strip 11. Such identification of a corrugated element 12 ′ with respect to an element located upstream with respect to it, if it ensures correct relative positioning of the two elements, however, implies putting at a precise dimension both part 22 and part 23 of each corrugated element 12 ′.

 In FIGS. 4 and 6, such relative positioning is ensured in a different manner, by giving for example to the front part 22 of a corrugated element disposed downstream of another element, a length substantially equal to that of a vertex of corrugation 13, and by placing this front part 22 of the downstream element on the rear part 23 of the upstream element, so that it comes into contact with the flank 19 of the most rear corrugation of the latter .

 Under these conditions it is possible to produce the rear part 23 of the upstream element of flat shape, this last part possibly being of any length, since it does not participate in the relative positioning of a corrugated downstream element with respect to a upstream corrugated element. This significantly simplifies the industrial implementation of the corrugated element.

 Of course, the positioning of the corrugated elements 12 ′, when they are asymmetrical in shape as shown in FIGS. 4 and 7, can also be carried out by placing the part 23 of greater length (which then becomes the front part d 'a downstream corrugated element) under the part 22 of shorter length (which then becomes the rear part of an upstream corrugated element).

 In an alternative embodiment of the invention shown in FIGS. 7 and 8, the front part 22 of the corrugated element 12 'is folded, substantially in the same direction as that of the rear flank 19 of the corrugated element upstream with which it is intended to come into contact, so as to form a rib 20. This rib 20 plays a role of stiffening which is particularly advantageous in the case where corrugated elements 12 ′ of thin thickness and large width.

 Of course, the joining of the corrugated elements 12 ′ with the strip 11 could be obtained by other means, namely riveting, bonding, etc.

 By making the corrugated sheet 12 in a modular manner, it is possible, by reversing laterally the successive corrugated elements 12 ′, to avoid the accumulation of errors and tolerances manifested on each of the corrugations, and which, by the play of superimpositions of the different turns likely to cause a taper of the device which may lead to its disposal.

 Finally, in certain types of applications it is important that the flow parameters between adjacent channels are very close to one another, and a controlled communication between these channels will be created to do this.

 Such communication can thus be obtained by using a strip 11 consisting of a porous element at least in the areas for which a given degree of interchannel communication is desired. The porosity rate of the strip 11 will allow the desired degree of communication to be adjusted.

 It is also possible, as shown in FIG. 9, to carry out such communication between adjacent channels, using two strips 11, 11 ′ spaced apart by a distance e, this distance making it possible to control the degree of interchannel communication.

 Such communication between adjacent channels can also be used to ensure mixing of fluids, and for example favor so-called "online mixing" operations.

Claims (14)

 1.- A method of manufacturing a plurality of adjacent adjacent channels (15) intended to ensure the partitioning of a flowing fluid stream into a plurality of identical elementary streams, the channels (15) being obtained by simultaneous winding, on a same core (1), of at least two sheets, namely a first flat sheet, or strip (11), and a second corrugated sheet (12), the corrugated sheet taking place between two successive turns of the strip (11) of so that the tops (14) of two of its successive undulations come respectively into contact with each of these turns, characterized in that one ensures a stiffening of the corrugated sheet (12), as and when it is put in place between the turns of the strip (11), by fixing the latter to said strip (11), so as to maintain substantially constant the radial spacing separating two successive turns of the strip (11).  2.- Method according to claim 1 characterized in that one uses a corrugated sheet (12) consisting of a series of separate elements (12 ') placed end to end, the junction between two successive elements (12') , namely an upstream corrugated element already in place and a downstream corrugated element to be put in place, by fixing the two elements (12 ') on the strip (11).  3.- Method according to claim 2 characterized in that a first end (22) of a corrugated element is abutted with the other end (23) of an adjacent corrugated element, so as to ensure the continuity of the undulation between the upstream corrugated element and the downstream corrugated element.  4.- Method according to claim 3 characterized in that the corrugated element ends at a first end by a wavy top (13), the latter being abutted against a wavy flank (19) of an adjacent wavy element.  5.- Method according to claim 4 characterized in that each corrugated element (12 ') ends at its other end by a flat part (23) coming into contact with a turn of the strip (11), this flat part receiving the first end (22) of an adjacent corrugated element.  6.- Method according to claim 4 characterized in that the transverse edge of said first end of a corrugated element (12 ') is curved so as to form a stiffening rib (20) substantially parallel to the side (19) of the 'corrugation of the corrugated element (12') with which it comes into abutment.  7.- Method according to claim 2 characterized in that one reverses each corrugated element laterally (12 ') with respect to the previous one so that a given side of one is opposite this same side on a corrugated element adjacent.  8.- Method according to any one of the preceding claims, characterized in that the fixing of the corrugated sheet (12) on the strip (11) is carried out for spot welding.  9.- Method according to any one of the preceding claims, characterized in that said fixing is carried out on an entire turn, consisting of a corrugated sheet (12) and a strip (11), after it has been covered. a new turn.  10.- Device for ensuring the partition of a flowing vein into a plurality of identical elementary veins, consisting of a plurality of adjacent channels (15) crossed by the fluid vein, these channels (15) being constituted by l spiral winding of at least one flat sheet, or strip (11), the radial distance separating two successive turns being substantially identical, a corrugated sheet (12) being arranged between two successive turns so that the vertices (13) of two of its successive undulations respectively come into contact with each of these turns, characterized in that the corrugated sheet (12) is stiffened by fixing to the strip (11).  11.- Device according to claim 10 characterized in that it comprises means of communication between adjacent channels.  12.- Device according to claim 11 characterized in that the strip (11) consists, at least over part of its surface, of a porous material.  13.- Device according to claim 11 characterized in that it comprises two strips (11,11 ') in contact with the same corrugated sheet (12), these two strips being spaced from one another in order to create a interchannel passage.  14.- Device according to any one of the preceding claims, characterized in that it comprises a corrugated sheet (12) consisting of a series of separate elements (12 ') placed end to end, the junction between two successive elements ( 12 '), namely an upstream corrugated element already in place and a downstream corrugated element to be put in place, being produced by fixing the two elements (12') to the strip (11).