METHOD FOR THE PRODUCTION OF EXTRUDED FILAMENTS WITH CONDUCTIVE ELEMENTS

Abstract

A method for the production of filaments (A) capable of being thermoregulated includes the steps of: —feeding a material to be extruded and a pair of wires (B) in electrically conductive material to an extrusion head (1); —extruding the material to be extruded and, at the same time, promoting the escape of the pair of wires (B) from the extrusion head (1) in such a way that the material to be extruded winds the pair of wires (B); —during the extrusion, generating at least a coupling portion (Y) of the filament (A), wherein the pair of wires (B) is electrically connected.

Claims

1. Method for the production of filaments (A) capable of being thermoregulated comprising the steps of: feeding a material to be extruded to an extrusion head (1); feeding a pair of wires (B) of electrically conductive material to said extrusion head (1); extruding the material to be extruded and, at the same time, promoting the escape of the pair of wires (B) from the extrusion head (1) in such a way that the material to be extruded winds at least partially and at least locally said pair of wires (B); generating, during the extrusion, at least a coupling portion (Y) of the filament (A) wherein pair of wires (B) is electrically connected, said coupling portion being preferably arranged internally to the material to be extruded.

2. Method according to claim 1, wherein it is further included a step of ejecting, preferably in an axial and/or periodic direction, at least a portion of the pair of wires (B) outside the material to be extruded.

3. Method according to claim 1, wherein it is also present a step of cyclically repeating all the steps of claim 1, said step of cyclically repeating being adapted to define at least two co-extruded articles made respectively in each cycle of steps.

4. Method according to claim 3, wherein it is also present a step of defining and/or leaving an axial gap between two articles being successively co-extruded one after the other in successive cycles, said axial gap being sufficient for a cutting operation suitable to separate said two co-extruded articles not to interrupt a circuit created by said coupling portion (Y) of the filament (A), wherein said pair of wires (B) is electrically connected.

5. Method according to claim 1, wherein said step of generating at least one coupling portion (Y) comprises a step of twisting the pair of wires (B) in such a way that said pair of wires (B) has at least one mutual contact point suitable to electrically connect them.

6. Method according to claim 1, wherein the step of feeding a material to be extruded comprises a step of mixing with said material to be extruded an electrically conductive additive (C) preferably in powder form, such that said additive (C) is dispersed inside the filament (A) and said step of generating at least one coupling portion (Y) comprises a step of compressing a portion of the filament (A) so as to compact the additive (C) increasing its volumetric density until generating an electrical contact between the wires (B).

7. Method according to claim 6, wherein after the step of mixing, the material to be extruded is composed of an additive (C) in a percentage in the range between 25% and 35%.

8. Method for the production of spiraled tubes capable of being thermoregulated comprising the steps of: extruding an elongated tape (D) having opposite side edges; winding said elongated tape (D) in such a way that the opposite side edges overlap, steadily constraining said opposite side edges to realize a helical junction area realizing a tubular body; extruding a filament (A) capable of being thermoregulated according to the method according to claim 1; winding said filament (A) capable of being thermoregulated around said tubular body, preferably overlapping said filament (A) capable of being thermoregulated on the area of helical junction.

9. Method according to claim 8, wherein the steps of extruding an elongated tape (D) and extruding a filament (A) capable of being thermoregulated are performed simultaneously and the steps of winding said tape (D) and winding said filament (A) are performed simultaneously.

10. Extrusion head comprising: a first nozzle (2) that can be connected to at least one propeller to receive from said propeller a material to be extruded and configured to extrude said material along an extrusion direction (X); an insertion device (3) configured to receive in feed a pair of wires (B) in electrically conductive material and having a pair of delivering seats arranged to deliver respective wires (B) along the extrusion direction (X); said first nozzle (2) being associated with the insertion device (3) so as to extrude the material to be extruded around the pair of wires (B) exiting the extrusion head (1) by completely winding them.

11. Extrusion head according to claim 10, wherein the first nozzle (2) and the insertion device (3) are coaxial, preferably said first nozzle (2) being disposed circumferentially around the insertion device (3).

12. Extrusion head according to claim 10, wherein said delivering seats are movable in rotation about an axis being parallel to the extrusion direction (X) so as to cause a twisting of the wires (B) exiting the extrusion head (1).

13. Extrusion head according to claim 10, wherein said delivering seats are movable along a path being transverse to the extrusion direction (X) so as to define a twisting of the wires (B) exiting the extrusion head (1).

14. Extrusion head according to claim 10, further comprising a compression device (4) configured to act on the filament (A) capable of being thermoregulated exiting from the first nozzle (2) by compressing it locally.

15. Extrusion head according to claim 10, comprising: a second nozzle (5) which can be connected to at least one propeller to receive from said propeller a material to be extruded and configured to extrude an elongated tape (D) having opposite side edges; and a spindle configured to promote a winding of the elongated tape (D) and said filament (A) capable of being thermoregulated in such a way that said opposite side edges overlap to form an area of helical junction realizing a tubular body and of said filament (A) capable of being thermoregulated around the tubular body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] FIG. 1 schematically shows a view of an extrusion head during the production of a spiraled pipe capable of being thermoregulated;

[0059] FIGS. 2A-2E show cross-sectional views with respect to an extrusion direction of some production steps of the spiraled pipe capable of being thermoregulated;

[0060] FIGS. 3A-3E show cross-sectional views with respect to an extrusion direction of some production steps of the spiraled pipe capable of being thermoregulated according to a further embodiment;

[0061] FIGS. 4A-4C show cross-sectional views with respect to an extrusion direction of some production steps of the spiraled pipe capable of being thermoregulated according to a further embodiment.

[0062] FIGS. 5A-5F show cross-sectional views with respect to an extrusion direction of some production steps of the spiraled pipe capable of being thermoregulated according to a further embodiment;

[0063] FIGS. 6A-6F show cross-sectional views with respect to an extrusion direction of some production steps of the spiraled pipe capable of being thermoregulated according a further embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0064] The present invention relates to a method for the production of filaments “A”, in particular of the type capable of being thermoregulated.

[0065] The term “capable of being thermoregulated” means that the filament “A” has characteristics and structure allowing the heat generation in a controlled manner.

[0066] In particular, this result is obtained thanks to the presence inside the filament “A” of an electrically conductive material, which is capable of generating heat due to the Joule effect.

[0067] That is to say that it is possible to vary a heat emitted by the filament capable of being thermoregulated by varying the electric current flowing inside it, so as to control the amount of power dissipated by the Joule effect.

[0068] In particular, the method of the present invention provides to feed a material to be extruded to an extrusion head 1 which will be disclosed in greater detail below.

[0069] For the purposes of the present description, the generic term “material to be extruded” refers to any known material suitable to be used in the field of extrusion processes, for example plastics, polymers or other materials which present at the same time characteristics of electrical insulation.

[0070] At the same time, a pair of wires “B” of electrically conductive material is fed to the same extrusion head 1.

[0071] The material to be extruded is then extruded promoting, at the same time, the escape of the pair of wires “B” from the extrusion head 1, in such a way that the material to be extruded forms the filament “A” around a pair of wires “B” by completely winding them.

[0072] In other words, the wires “B” turn out to be (in an exemplifying but of course non-limiting embodiment according to the present invention) completely immersed and enclosed within the filament “A”.

[0073] During the extrusion process, it is provided at least one coupling portion “Y” of the filament “A” wherein said pair of wires “B” is electrically connected.

[0074] In other words, the wires “B” are fed to the extrusion head 1 independently of one another and will respectively represent two distinct branches of the electric circuit to be produced inside the filament “A” in order to allow the passage of current.

[0075] During the extrusion, the circuit is then closed by realizing the at least one coupling portion “Y”, wherein an electrical connection is generated between the two wires “B”, which allows the transmission of charge carriers, and therefore the passage of current, between the two.

[0076] According to a first possible embodiment, shown in FIG. 1 and with greater detail in FIGS. 2A-2E and FIGS. 3A-3E, the generation of the electrical contact portion provides the twisting of the pair of wires “B” so as to realize at least one mutual contact point arranged to electrically connect them.

[0077] In other words, according to this embodiment, the position of the wires “B” inside the filament “A” is changed during extrusion so that the wires “B” are progressively brought closer until they come into mutual contact in correspondence with the coupling portions “Y”.

[0078] Alternatively, according to a further possible embodiment, shown schematically in FIGS. 4A-4C, the generation of the coupling portion “Y” does not occur by the approach of the wires “B” to make a mutual contact, but by short-circuiting the two by a deformation of the filament “A”.

[0079] In particular, according to this embodiment, the step of feeding the material to be extruded to the extrusion head further provides to mix with it an electrically conductive additive “C” in powder form (or an electrically conductive polymer such as polyaniline or polyacetylene) in such a way that the additive “C” is dispersed within the filament.

[0080] The term “in powder form” means that the additive is in a granular or in any case discrete form, with grains of a size suitable for determining a homogeneous dispersion of the additive inside the matrix of the material to be extruded, once this is extruded to make the filament “A”.

[0081] It should be noted that the expression “granular form”, introduced above, is intended to mean a state of aggregation of the additive which has a plurality of solid corpuscles or in any case with an individual density comparable to the solid state: such corpuscles can then have the most disparate geometric configurations and/or the most disparate chemical compositions, such as leaves, needles, pipes, nanopipes and so on (such granules can then be made by way of example of, but not limited to, graphene, metal or carbon fibres and anything else depending on the needs of the moment).

[0082] The generation of the at least one coupling portion “Y” will then be obtained by compressing a portion of the filament in such a way as to compact the additive “C” until an electrical contact is generated between the wires “B”.

[0083] In other words, the additive “C” dispersed within the filament “A” does not have per se a sufficient density to allow the passage of charge carriers, however, as a result of compression, the particles of the additive “C” are compacted by approaching until obtaining a volumetric density being sufficient to allow locally a flow of charge carriers, thus short-circuiting the two wires “B” in correspondence of the coupling portion “Y” where the compression occurred.

[0084] Preferably, the material to be extruded has a percentage of additive “C” therein in the range between 25% and 35%, so as to guarantee a sufficient quantity of additive “C” for the generation of electrical contact between the wires “B” following the compression, without compromising at the same time the mechanical and structural characteristics.

[0085] The filament “A”, produced by the present invention, thus allows to control an amount of heat generated by the Joule effect from the flowing of an electric current inside the wires “B” producing a closed circuit, thanks to the arrangement of the coupling portions which are precisely designed to generate an electrical contact of the pair of wires “B”.

[0086] It is worth noting that by implementing, with the present method, an embodiment of a co-extruded article wherein the two wires of the pair “B” are of different metals (for example: copper and constantan, nickel and chromium, platinum and rhodium, and anything else depending on the needs of the moment), it is advantageously possible to create a thermocouple. In addition, the combination (by means of the co-extrusion) of a first pair of wires of the same conductive metal and of a second pair of wires which are metallically different from one another, together with an operative step of giving suitable coupling of these pairs at an electrical/circuit level, would allow to obtain a closed-loop thermoregulator device (wherein, the current with consequent generation of the Joule effect circulates in the first pair of wires, and wherein the second pair of wires acts as a regulator/selector on the passage of the same current).

[0087] The present invention also relates to a method for the production of a spiraled pipe capable of being thermoregulated, that is to say pipes which allow to accurately adjust the temperature of the fluid that flowing inside them, providing more or less heat generable by the Joule effect, varying the characteristics of the electric current flowing therein.

[0088] In particular, the method provides the extrusion of an elongated tape “D” having opposite side edges.

[0089] The tape “D” is then wound up according to a helical or spiral path, so that the opposite side edges overlap to form an area of helical junction.

[0090] In this way a tubular body is made.

[0091] In other words, the pipe is formed by winding the extruded tape “D” along a spiral path, so as to obtain an at least partial overlap of the opposite side edges of the tape “D” which are then constrained to each other.

[0092] The realization of the area of helical junction, i.e. that portion of the tubular body wherein the opposite side edges of the tape “D” are overlapped and mutually constrained, is preferably carried out when the extruded material is still not completely cooled and solidified, so as to allow that the opposite side edges are welded together.

[0093] The method also provides for extruding a filament “A” capable of being thermoregulated according to the above description.

[0094] That is to say that it is extruded a filament “A” having therein a pair of electrically conductive wires “B” and at least a coupling portion “Y” suitable for generating an electrical contact between the two wires “B” of the pair.

[0095] The filament “A” is then coupled to the tubular body by winding it helically around it, preferably by overlapping it on the area of helical junction.

[0096] In this way, the wire is placed directly in contact with the tubular body and is permanently connected thereto, so that it can transmit by conduction the heat generated by the dissipation of the electric power generated therein by the passage of current inside the circuit defined by the pair of wires “B”.

[0097] Advantageously, by overlapping and constraining the filament “A” to the area of junction, it is possible to further tighten the coupling generated between the opposite side edges which define the area of junction itself, making more resistant the spiral pipe capable of being thermoregulated.

[0098] According to a preferred embodiment, the extrusion of the filaments “D” and “A” is carried out simultaneously.

[0099] In other words, it is possible to realize at the same time, preferably by means of a same extrusion head, both the filaments “D” and “A”.

[0100] In the same way, it is possible to simultaneously execute the winding step of the tape “D” to make the tubular body and the winding step of the filament “A” around it simultaneously.

[0101] It is observed that the winding steps can be carried out simultaneously even if the extrusion steps are carried out separately, i.e. It is possible to realize the spiraled pipe capable of being thermoregulated by simultaneously winding the tape “D” and the filament “A” to realize the pipe, even if these components have been extruded at different times.

[0102] The present invention also relates to an extrusion head.

[0103] In FIG. 1, the numerical reference 1 generically indicates an extrusion head configured for the production of a filament “A” capable of being thermoregulated starting from a material to be extruded.

[0104] The extrusion head disclosed herein is particularly suitable for carrying out the above-disclosed method and comprises a first nozzle 2 and an insertion device 3.

[0105] The first nozzle 2 can be connected to at least one propeller of the known type (not shown in the attached figures) which receives the material to be extruded from a tank, a hopper or any other container suitable for storing a material to be extruded and feeding it to the extrusion head 1.

[0106] The first nozzle 2 is then fed by at least one propeller and is configured to generate the filament “A” along an extrusion direction “X”.

[0107] The insertion device 3 is instead configured to receive in feed a pair of wires “B” in electrically conductive material, such as for example copper or other suitable conductive metals and has a pair of delivering seats arranged to deliver respective wires “B” exiting from the extrusion head 1.

[0108] In other words, the wires “B” are fed to the insertion device 3, and in particular they are passed through respective delivering seats which allow it to be transferred to the extrusion head 1, in particular along the extrusion direction “X”.

[0109] The extrusion nozzle 2 is associated with the insertion device 3, in such a way that the material to be extruded is processed realizing the filament “A” around the pair of wires “B” completely winding them.

[0110] In particular, the extrusion nozzle 2 and the insertion device 3 are coaxial, preferably the extrusion nozzle 2 has a circular profile arranged around the insertion device 3.

[0111] According to a first embodiment, some configurations of use of which are shown in FIGS. 2A-2E, the delivering seats are movable in rotation about an axis being parallel to the extrusion direction “X” so as to cause a twisting of the wires exiting the extrusion head.

[0112] In other words, it is possible to rotate the delivering seats while simultaneously executing the extrusion aimed at making the filament “A”.

[0113] The tension to which the wires “B” are subjected and the consequent friction with the extruded material not yet completely solidified exiting from the extrusion head 1, allow to firmly fix the contact point of the two wires “B” in the coupling portion “Y”, where it is thought to be provided according to the technical specifications of the filament “A2” to be produced.

[0114] Alternatively, as shown in FIGS. 3A-3E, the delivering seats are movable along a transverse direction to the extrusion direction “X” so as to cause a twisting of the wires exiting the extrusion head.

[0115] In other words, the delivering seats move alternately between respective starting and ending positions, wherein the starting position of a seat corresponds to the arrival position of the other seat and vice versa.

[0116] According to this embodiment, it is therefore present an intermediate position, wherein the two delivering seats will substantially change position.

[0117] According to a further possible embodiment, shown schematically in FIGS. 4A-4C, the extrusion head 1 comprises a compression device 4 configured to act on the filament “A” capable of being thermoregulated exiting the extrusion nozzle 2 by compressing it locally.

[0118] In particular, this embodiment can be advantageously used when the material to be extruded is mixed with an electrically conductive additive “C” in a percentage in the range between 25% and 35%, so that the compression generated by the compression device 4 allows to thicken the additive “C” until the coupling portion “Y” is generated by placing the two wires “B” in electrical connection.

[0119] The extrusion head 1 of the present invention can also be arranged for the realization of a spiraled pipe capable of being thermoregulated, in particular according to the above-outlined method.

[0120] To this end, the extrusion head 1 includes a second nozzle 5 which can be connected to at least one propeller to receive from it a material to be extruded and configured to extrude an elongated tape “D” having opposite side edges.

[0121] Advantageously, the first nozzle 2 and the second nozzle 5 can be made by means of a single element having an extrusion profile suitable for simultaneously producing the filament “A2” capable of being thermoregulated and the tape “D”.

[0122] Likewise, the first nozzle 2 and the second nozzle 5 can be fed and operated by means of the same propeller.

[0123] The extrusion head may also include a rotating spindle configured to promote a helical winding of the elongated tape “D” and of the filament capable of being thermoregulated in such a way that the opposite side edges overlap to form an area of helical junction realizing a tubular body. Consequently, the filament “A” capable of being thermoregulated will be wounded around the tubular body.

[0124] Advantageously, the extrusion head 1 of the present invention allows to produce filaments “A” capable of being thermoregulated and/or spiraled pipes capable of being thermoregulated wherein the electric circuit designed to generate the Joule effect is completely formed and integral to the structure of the realized product, therefore without requiring further processing steps by the end user.

[0125] From the point of view of the advantages, it must therefore be observed that the present invention allows to realize both the “filaments” suitably connected from the electrical and/or circuit point of view, and a wide range of articles (including these filaments capable of being thermoregulated) which for example can be profiles (extruded), pipes, straps or tapes.

[0126] At the same time, the invention allows to place the wires/filaments between elements which are combined in different ways with the structure of the articles: for example, in the case of realization of a “spiraled” product the filaments can be arbitrarily positioned between the helical thickening that composes the “rib” of the spiraled article and the below cylindrical body (and no longer only “inside” the helical thickening, as occurs in the production methods of known art), or even in the cylindrical body of the spiraled article or even under the latter (this last embodiment variant can be implemented by taking advantage of the crushing “from below” enforceable to all that is co-extruded during the implementation of the method itself).

[0127] The considerable variability of configurations and/or relative positions between the material constituting the extruded body and the filaments ultimately allows to generate an important advantage, namely that of having the heating element closer to the content in transit through the article (e.g. a fluid to be heated which must pass through a tubular article produced according to the method of the invention).

[0128] Furthermore, it can be noted that the possibility of twisting—and therefore of “bridging” or short-circuiting the wire—is obtained through different types of physical phenomena that can be exploited during the co-extrusion according to the present method: for example, in is possible to take advantage of the friction between the forming element (i.e. the spindle of the co-extruder) and the material, for example polymeric material, which is deposited thereon and then welded with the next coil in an embodiment of a spiraled article.