FR2477433A1 - METHOD AND DEVICE FOR APPLYING AN INSULATING PROTECTIVE COATING ESPECIALLY TO LONG-LONG METALLIC ELEMENTS SUCH AS THREADS, TUBES OR STRIPES, AND COATED ELONGATED ELEMENTS - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS AND A DEVICE FOR APPLYING A PROTECTIVE COATING ON EXTENDED METAL ELEMENTS SUCH AS WIRES, TUBES OR STRIPS. THE DEVICE INCLUDES AT THE PROTECTIVE COATING APPLICATION STATION 3 AT LEAST ONE CHUTE 6 WITH BOTTOM 7 OPENED IN 8 THROUGHOUT ITS LENGTH IN THE DIRECTION OF PASSAGE OF THE LENGTH ELEMENT 1 AS WELL AS MEANS 10 FOR FEEDING PULVERULENT PRODUCT 4 OF PROTECTIVE COATING WHICH MAKES IT CIRCULATE IN A DIRECTION NOT PARALLEL TO THE DIRECTION OF PASSAGE OF THE EXTENDED ELEMENT 1 AND ADVANTAGEOUSLY IN A PERPENDICULAR DIRECTION IN PARTICULAR BY GRAVITY DROP IN THE CASE OF THE EXTENDED ELEMENT 1 PASSES SENSITIVELY HORIZONTALLY IN THE SLOW THE INVENTION ALLOWS A FASTER PASSAGE RATE OF THE EXTENDED ELEMENTS 1 AND THE OBTAINING OF A UNIFORM AND BETTER QUALITY PROTECTIVE COATING.

Description

The present invention essentially relates to a method and a

  device for applying an insulating protective coating, especially on elongated elements

  Metals such as wires, tubes or strips.

  As an insulating protective coating, there may be mentioned for example a plasticizer product but other products

  Insulating protectors can of course be used.

  There are already known various methods and devices for plasticizing elongate metal elements such as son or strip. One of these methods and known devices comprises the passage of elongated metal elements, after preheating, with possible application of an adhesive product, in a vibrated bed of synthetic resin powder for a relatively long time of the order of a few seconds in order to coat or coat said

  elongated metal elements with said synthetic resin.

  Thereafter, a hardening treatment can be carried out in an oven before cooling the coated elongate elements.

  by quenching in a water bath for example.

  However, such a process of plasticization is not entirely satisfactory since it is not possible to obtain a uniform coating of the elongate metal elements since the particles of plasticizer product are generally kept in contact with the elongate elements during a period of time. a relatively long time, which causes the heating of the particles of plasticizer product in the vicinity of the passage of the elongated elements while the distribution of the particles of plasticizer product is not carried out uniformly around the

elongated elements.

  Moreover, the known methods and devices generally do not lend themselves to the use of elongated elements of different calibres and to the production of coatings of different thicknesses so that they are not of one size.

flexible employment.

  In addition, with the prior methods and devices, the passage of the elongated elements is generally relatively long to obtain a correct coating while the dimensions of such devices are generally important,

  that is to say of the order of 60 meters.

  The present invention therefore aims to overcome the aforementioned drawbacks by providing a solution which

  allows a better flexibility of realization of the opera-

  plasticizing, and more generally the operation of applying protective coating advantageously insulating, such as a coating of plasticizer product, while obtaining a passage of the elongated elements much faster while maintaining or even improving the quality , in particular the uniformity of the coating with the implementation of a device of more reasonable size without reducing its performance. Preferably this

  solution must be of particularly simple design.

  This solution consists according to the present invention in

  a method of applying a protective coating which is

  insulating gum, such as a coating of plasticizer, in particular on elongated metal elements, such as wires, tubes or strips, of the type comprising the passage of each elongated element, preferably preheated, in a coating application zone protector supplied with a protective coating product, such as a plasticizer, in powder form, and then cooling each elongated element coated or coated with a protective coating product, characterized in that the coating powder product is circulated. protector in a homogeneous and uniform manner in a direction not parallel to the direction of passage of said elongate member in said protective coating application zone, in order to obtain a continuous and uniform coating all around each elongated element by continuous renewal of said

  powdery product all around each elongated element.

  According to a particular embodiment of this method, the passage of each elongated element is carried out substantially horizontally while the protective coating powder product is circulated advantageously substantially perpendicularly to the direction of

passage of said elongate member.

  Preferably, a continuous flow of the protective coating powder product is effected at a substantially constant predetermined speed, causing gravity to drop through the protective coating application area on each elongated member and beyond.

of it.

  According to a preferred feature of this method, each elongated element being heated before entering the protective coating application zone, the heating of each elongate element is maintained on at least part of its path in the application zone of protective coating, which allows to act at will on the temperature inside the protective coating application area and around to allow a passage of elongated elements much faster in

  the protective coating application area.

  According to another particularly advantageous embodiment of the process according to the invention, after the passage of each elongated element in the protective coating application zone and before its cooling, a finishing treatment of the surface state is carried out advantageously by maintaining said heating elongated elements. According to a particular embodiment, the elongated elements are heated at each step mentioned above by induction. Moreover, it is advantageous to use as a protective coating product a self-adhesive product with excellent adhesiveness.

  vis-à-vis the elongated element to be coated.

  The present invention also relates to a

  protective coating application device

  insulating gum including on elongate metal elements such as son, tubes or strips successively comprising, preferably a preheating station of each elongated element, a protective coating application station comprising the use of a powdery protective coating product, such as a plasticizer, and a cooling station of each coated elongated element, characterized in that the protective coating application station comprises at least one trough or open bottom trough over its entire length in the direction of passage of the elongated element, as well as means

  supply of powder protective coating product

  slowly circulating said protective coating product in a direction not parallel to the direction of passage of the elongate member. According to one embodiment of this device, the direction of passage of the elongated element being substantially horizontal, the hopper is arranged vertically and the protective coating product supply means comprise a supply circuit protective coating product opening in the hopper above

of each elongated element.

  Advantageously, this protective coating product supply circuit comprises below the aforementioned open bottom of the trèmie a receiving member of the protective coating product falling out of the trèmie in order to

  allow recycling of the protective coating product.

  Preferably, the receiving member comprises a sieve for separating the physically modified product particles by passing through the protective coating application station, said sieve advantageously being at the surface

3. inclined and / or vibrated.

  Other objects, features and advantages of the present invention will become apparent in light of the

  explanatory description which will follow made reference

  to the accompanying drawings representing a presently preferred embodiment of the present invention, given merely by way of illustration and which can in no way limit its scope. In the drawings: - Figure 1 shows a schematic view of an embodiment of a device according to the present invention essentially at the application station of a protective coating advantageously insulating; the application of an insulating protective coating of a wire has been schematically represented as an example of elongate metal elements; - Figure 2 is a sectional view along the trace line II-II of Figure 1; and - Figure 3 is a sectional view along the line

trace III-III of FIG.

  With reference to FIGS. 1 to 3, a device for applying

  cation of a protective coating advantageously insulating, such as a coating of a plasticizer, including elongated metal elements such as son 1, tubes or strips comprises successively, preferably a preheating station 2, an application station of protective coating 3, comprising the use of a protective coating product advantageously insulating 4, such as a coating of a plasticizer (see Figure

  2) and a cooling station symbolized in 5.

  This protective coating application device is characterized according to the present invention in that the protective coating application station 3 comprises at least one chute or hopper 6 with a bottom 7 open at 8 along its entire length in the direction of passage of the liner. 'element

  1, as can be seen in Figure 3. This arrangement

  tif also comprises means for supplying a protective coating product 4, such as a

  plasticizer, circulating the product of

  protector in a direction not parallel to the direction of passage of the elongate element 1 as can be seen in FIG.

figure 2.

  According to a particularly advantageous embodiment, represented in FIGS. 1 to 3, the direction of passage of the elongated element is substantially horizontal, the trough 6 is arranged vertically, and the feed means 10 of protective coating product 4 comprise a feeding circuit 11 protective coating product 4 opening 12 in the hopper 6 above each

elongate element 1.

  Advantageously, this feed circuit 11 protective coating product 4 comprises below the bottom 7 (open 8) of the hopper 6 a member 14 for receiving the protective coating product 4 falling out of the hopper 6 to allow recycling the protective coating product 4 by any appropriate means,

  such as a pump, as can be seen in Figure 2.

  According to an advantageous characteristic, the receiving member 14 may comprise a sieve 15 for separating the

  particles of protective coating product 4 physical-

  modified by passing through the application station

  The screen 15 may be of advantage

  with an inclined surface and / or vibrated to facilitate the separation of said particles of product 4 physically

changed.

  In addition, this device may comprise a finishing station between the protective coating application station 3 and the cooling station 5. Each preheating station 2, protective coating application 3o 3 and finishing 20 may comprise heating means 22, 23 or high temperature maintenance of each elongated element advantageously constituted by inductors as can be seen in Figures 2 and 3. It should be noted that in the example shown are the same heating means, that is to say two inductors 22 and 23 disposed on either side of the elongated element 1 or a group of elongate elements 1 which are used to preheat the elongate element 1, such as a wire, to maintain high temperature in the protective coating application station 3 and to perform a finishing treatment in the station 20. In this regard, it is understood that the spacing of the inductors 22 and 23 can be different at each station to modulate the temperature of the elongated element 1,

  which allows to obtain a better flexibility of the opera-

  application of protective coating, with

  obtaining a better quality of the protective coating

  tor. It should be noted that the heating means 22, 23 of the protective coating application station 3 are preferably arranged outside the hopper 6 and the trèmie is in this case made of a non-sensitive material. inductions, such as aluminum. It should be noted in this regard that the inductors 22 and 23 can be formed by plates as can be seen well in

Figures 2 and 3.

  In addition, the portion 24 of the hopper 6 located under the elongated element 1 comprises at least one wall section inclined so as to partially cut the flow of powder product 4 falling on either side of the element. 1 or elongated element group 1 to direct it under the elongated element 1 to completely surround it as symbolized by the arrows F in Figure 2. This is intended to obtain a homogeneous stream to obtain a continuous coating and

  homogeneous around each elongated element.

  Advantageously, the preheating station 2, the

  finishing station 20 and possibly the application station

  Protective coating 3 may comprise a hood 26, 27 or fume extractor which are sucked in order to be evacuated out of the installation and treated before releasing into the atmosphere to avoid

any pollution.

  In addition, the cooling station 5 includes

  advantageously a bath circulating against the thermocurrent

  regulated. According to a particular characteristic, one can

  to use as an advantageous protective coating

  insulating a self-adhesive product. Such a self-adhesive product is advantageously a product having an excellent adhesive capacity vis-à-vis the element

  to be coated and often the self

  most suitable adhesive to form a good chemical reaction for the best adhesion of the coating

on the elongated element.

  In the case where the protective coating product has no self-adhesive capacity, upstream of the preheating station 2, it is advantageous to provide an adhesive product application means (not shown) by any suitable system of deposition, eg simple spraying, electrostatic spraying, bathing, etc. The adhesive product chosen is advantageously the one that is most suitable for forming a good chemical reaction for the best possible adhesion of the

  coating on the elongated element.

  Also, in the case of fat or dirty elongate elements, it can be carried out prior to a degreasing and cleaning thereof by any suitable system for example by ultrasonic sound, degreasing bath, shot blasting, etc. The operation of the device described above is the following with reference to the method according to the invention and the application of an insulating protective coating, such as a plasticization, of a continuous metal wire as

  example of elongated metal elements. -

  As the wire 1 is for example wound on a basket or a support, this wire is unwound for example at a

  speed varying according to the various operating parameters

  such as ambient temperature, wire diameter,

  the melting temperature of the powder coating product

  protective effect used. This speed varies according to the aforementioned parameters from a hundred meters per minute. If it is greasy or dirty, it is optionally passed through a degreasing and cleaning system and then an appropriate adhesive product is applied thereto in the case where the protective coating product is applied.

  is not itself self-adhesive, for example by spraying

  tion. Then, in the case of application of adhesive product, it is preferably passed through the preheating station 2 which allows the adhesive to dry, the heating of the wire 1 being carried out by induction at medium frequency or high frequency, by means of the heating means constituted by the inductors 22 and 23 up to a temperature of the order of 160 to 1800 ° C. in the case where a powdery product of polyvinyl chloride is used as the powdery product, the fumes released by this heating being sucked by the hood 26 which comes for example very

  near the thread, ending for example with a "goose pie".

  After passing through the preheating station 2, the wire or group of wires 1 passes into the protective coating station 3 at a speed identical to the unwinding speed of the wire

  while circulating the protective coating product

  4 in a direction homogeneous and regular in a direction not parallel to the direction of passage of the elongated element in the protective coating application zone 3, which is in this case defined by the hopper 6 in order to provide a continuous renewal of product powdery 4 all around

  1. In the example shown, the circula-

  pulverulent product 4, consisting for example of

  polyvinyl chloride, is carried out substantially

  perpendicularly to the direction of passage of the elongated element 1 and advantageously it achieves the continuous circulation of the

  pulverulent product 4 at a predetermined speed substantially

  constant by causing it to drop by gravity from the end 12 of the feed circuit 11 through the protective coating application zone 3 to each wire 1 and beyond it as seen clearly from of Figure 2. It should be noted that the heating of each wire 1 is maintained on at least part of its path in the protective coating application area 3 delimited by the trèmie 6 which increases the speed passing the wire. It should be noted that this heating in the protective coating application zone 3 is intended to keep each wire 1 at a high temperature, this temperature is of course predetermined and may be different from the temperature of the wire 1 before entry. in the protective coating application area

  3 and after passing through the coating application area,

protective effect 3.

  Moreover, because of this continuous circulation of the pulverulent product 4 in a homogeneous and regular manner, undesirable heating is avoided, which makes it possible to obtain a homogeneous and advantageously insulating protective coating.

wire 1.

  In this regard, it should be noted that one can foresee a

  maintaining the pulverulent product 4 at a predetermined temperature

  completed in order to increase the efficiency of the roof coating operation preserving the flow capacity of the powdery product 4. For this purpose, it is possible to provide means for preheating the powdery product 4 disposed on

  the supply circuit 11 (see Figure 2).

  It should be noted again that the pulverulent product 4 falling from the trèmie 6 is collected, using the organ

  14 that is recycled by the power supply circuit.

  11 substantially at the top of the trèmie 6 for a new passage. It should be noted that this recycling generally fcilite maintaining the aforementioned temperature of the product

powdery 4.

  Advantageously, the pulverulent product stream 4 falling from the trough 6 is sieved to separate the particles of powdered product 4 physically modified by passing in the vicinity of the heated wire 1, said modified particles being recovered in a separate vessel (not shown) and of course not recycled. It should be noted in this regard that one can play on the heating temperature of the elongated element 1 in the protective coating application zone 3 or the temperature of the powdery product 4, which allows to modulate at will the plasticizer coating thickness obtained. Another parameter is, of course, the speed of passage of the wire, which conditions the passage time of the wire 1 in the stream or powder product bath 4 and also the flow velocity of the

powdery product 4.

  In this regard, it is possible to have in series a plurality of separate zones for the application of protective coating 3, or in parallel to modify at will the capacity of

  treatment of the device according to the invention.

  To facilitate the circulation of the product stream

  powder 4, it is advantageously vibrate the trèmie 6.

  Wire 1 coated over the entire area of application

  protective coating cation 3 passes through the finishing station 20 where it is maintained at a high temperature

  by the heating means 22, 23 playing on the spread

  of the inductors 22 and 23, which makes it possible to accelerate

  the application of the protective coating and

to regulate the surface condition.

  Then, the finished surface-coated wire is cooled in the cooling station 5 by passing in a bath, for example thermo-controlled water advantageously against the current which can be any refrigerated system, possibly recycling, known in the technique; then we eventually wind up the wire

  reeled on baskets or supports.

  We can see that we obtain all the technical advantages mentioned above. It should be noted that the method El idispositif according to the invention make it possible to achieve

  to a decrease in the length of the complete installation.

  Indeed, it is possible to obtain a protective coating with a complete device of about fifteen meters in length instead of 60 meters compared to the previous devices,

  which constitutes a considerable progress.

  It should be noted that it is advantageous to maintain a constant level of powdery product 4 of protective coating in the trèmie-6. This can be achieved by a level probe system which makes it possible automatically to feed the trèmie 6 in powdery product 4 for

keep the level constant.

  Furthermore, it is understood that the method and the device of the present invention can be adapted to all the powders and especially as mentioned previously to the self-adhesive powders which allows to remove in

  this case the adhesive product deposition station.

  This great adaptability is due to the fact that one can: - automatically and independently vary the speed of each elongated element 1; varying the induction by the power by the spacing of the electrodes or inductors 22, 23 independently for each station or step; - vary the speed of passage of the powdery product 4 in the trèmie 6 including the lower opening; - vary the temperature of the cooling bath; - Play on the temperature of each elongated element, the powdery product 4 by taking the temperature of each elongate element 1, the powdery product 4 and the ambient temperature; - - possibly vary the length of the bath of pulverulent product 4 by obtrusion of certain elements (manually or automatically); vary the speed and the temperature of the wire according to the diameter of the wire and the pulverulent product 4 used and its melting temperature;

  - vary the power of the inductor.

  Therefore, also by the knowledge of the speed of passage of the wire, the inductive power, the melting temperature of the powdery product 4, it is possible to obtain automatically according to the diameter

  of wire an elongated element coated with quality and by

  itrle, the required thickness of coating. This will provide manual or automatic control. particularly

sought after in the industry.

  Of course, the invention is not limited to the embodiment described and shown which has been given by way of example. In particular, the invention comprises all the means constituting technical equivalents

  described means, as well as their combinations, if these

  these are executed according to his spirit and implemented in

  the framework of protection as claimed. Thus the invention

  The invention also relates to elongated elements, such as wires, tubes or strips, characterized in that they comprise a protective coating advantageously insulating

  which is preferably made from a coating product

  self-adhesive powder obtained by the process or

previously described device.

Claims (21)

R E V E N D I C A T IO N S   A method of applying an advantageous insulating coating such as a coating of a product   plasticizer, especially on elongated metal elements   such as wire, tube or strip, of the type   passing each elongate member, preferably preheated, into a protective coating application area supplied with a protective coating product, such as a plasticizer, in powder form, and then cooling each coated or coated elongate member; coated with protective coating material, characterized in that the protective coating powder product is circulated in a uniform and uniform manner in a direction not parallel to the direction of passage of said elongated member in the protective coating application zone in order to obtain a continuous and uniform coating all around each elongated element by continuous renewal of said powdery product   all around each elongated element.   2. Method according to claim 1, characterized in that the passage of each elongated element is carried out substantially horizontally while the protective coating powder product is circulated advantageously substantially perpendicular to the direction of passage of said elongate member.   3. Method according to claim 1 or 2, characterized in that a continuous circulation of the protective coating powder product, at a substantially constant predetermined speed, by causing it to drop by gravity through the coating application zone.   protector on each elongated element and beyond that this. -   4. Method according to one of claims 1 to 3,   characterized in that, each elongated member being heated prior to entering the protective coating application area, heating of each elongate member is maintained over at least a portion of its path in the protective coating application area; preferably the powdery product is also maintained at a predetermined temperature.   5. Method according to one of claims 1 to 4,   characterized in that after the passage of each element   lying in the protective coating application area   before its cooling, a finishing treatment of the surface state is carried out advantageously by means of a   maintaining said heating of the elongated elements.   6. Method according to one of claims 1 to 5,   characterized in that heating of the elements   elongated at each step by induction.   7. Method according to one of claims 1 to 6;   characterized in that the aforementioned protective coating application area is delimited by a trough or open bottom trammel along its entire length in the direction   elongated elements, and that it is preferable happily vibrate.   8. Process according to Claim 7, characterized in that the powdery coating product is collected.   protector falling from the hopper which is recirculated   at the top thereof for a new pass, and preferably using a coating product self-adhesive protector.   9. A method according to claim 8, characterized in that sieving the powder product stream of protective coating falling from the trèmie to separate   physically modified particles.   10. Method according to one of claims 1 to 9,   characterized in that each elongated element is cooled by passing it through a circulating bath advantageously countercurrently.   11. Processes according to one of claims 1 to 10,   characterized in that, in the case where the protective coating powder product has no tack property, a suitable adhesive product is deposited on each element lying down before preheating.   12. Advantageously insulating protective coating application device including on elongated metal elements, such as son, tubes or strips, comprising successively, preferably a preheating station of each elongate element, a protective coating application station comprising use of an advantageously insulating protective powder coating product, and a cooling station of each coated elongate element, characterized in that the protective coating application station comprises at least one trough or open bottom trough over its entire length in the direction of passage of the elongated element, as well as powder coating material supply means for circulating said powdery product in a non-parallel direction   in the direction of passage of the elongated element.   13. Device according to claim 12, characterized in that the direction of passage of the elongated element being substantially horizontal, the trèmie is disposed vertically and the powdered powder feed means aforesaid comprise a feed system of powder product leading to in the trèmie above each elongated element. 14. Device according to claim 13, characterized in that the feed-stream of pulverulent product aforesaid comprises below the aforementioned open bottom of the hopper a receiving member of the powdery product falling out of the trèmie to allow recycling of the product   powdery protective coating.   15. Device according to claim 14, characterized in that the receiving member comprises a screen for separating the protective coating material particles physically modified by passing through the protective coating application station, said screen being   advantageously inclined surface and / or vibrated.   16. Device according to one of claims 12 to   15, characterized in that it comprises a finishing station between the protective coating application station and the cooling station, each preheating station,   application of protective coating and finishing   nant means for heating or maintaining high temperature of each elongated element advantageously constituted by inductors, the trèmie being in this case made of a material not sensitive to inductions such as aluminum. 17. Device according to claim 16, characterized in that the heating means of the protective coating application station are disposed outside the aforementioned trèmie, and in that it comprisesAbs predetermined temperature holding means of the product powder disposed on the aforementioned feed circuit   in powdery protective coating product.   18. Device according to claim 16 or 17, characterized in that the aforementioned heating means are constituted by at least two inductors placed on either side of each elongated element or group of elongated elements, said inductors being preferably constituted by plates.   19. Device according to one of claims 12 to 18,   characterized in that the portion of the hopper located below the at least one elongate member comprises at least one wall section inclined to at least partially cut off the flow of protective coating powder product falling on either side of the elongate elements for directing it under the one or more elongated elements   to completely surround the one or more elongated elements.   20. Device according to one of claims 12 to 19,   characterized in that said cooling station comprises a countercurrent flow bath; and in that the device further comprises means for applying an adhesive product upstream of the protective coating application station and the preheating station when it is present, and in the case where the powder coating product protector has no adhesive property.   21. Elongate elements, such as wires, tubes or strips, characterized in that they comprise an advantageously insulating protective coating which is preferably made from a self-adhesive powder coating product, obtained by the process according to   one of claims 1 to 11 or by the use of   Device according to one of Claims 12 to 20.