FR2496523A1 - Surfacing elongated stock by electric arc discharge - using electrodes arranged either side of stock in vacuum chamber - Google Patents

Abstract

Arc discharge appts. for surfacing elongated stock comprises two electrodes spaced from the surface of the stock being cleaned each connected to a power source for feeding the arc discharge. The electrodes are arranged on opp. sides of the stock in a vacuum chamber and are displaceable relative to the stock. The power sources are connected to the stock via current conductors. Used for arc cleaning the surface of wire stock, tubular stock or ribbon-shaped stock of scale and grease, ans also refining and heating of the stock. The appts. can provide a very smooth surface on elongated stock and can be used for drying coats applied to welding wire stock.

Description

 The present invention relates to techniques for treating products with an electric arc and in particular relates to an installation for the treatment of long products with an electric arc.

 The invention can be applied in particular to strip products of the wire, tube, strip type, with a view to ridding them of scale and grease, to improve the surface layer of the metal of these products, as well as to heat the metal if necessary.

 We contact an installation for the treatment of long products with an electric arc (RFA patent N 1283645, cl. C23G, published in 1969), which comprises an electrode located at a given distance from the product to be treated, a power source. arc discharge, connected to the electrode and to the product, and a current supply member which makes the connection of the power source and the product. The electrode has a ring placed coaxially with the product. A homogeneous treatment of the product is then obtained thanks to the use of a magnetic system which generates a magnetic field which rotates the arc (the arc discharge) in the distance between the product and the electrode.

 In the device of the known type, the value of the voltage of the rotating arc is high, which makes the safety conditions worse when working with the device in question. In addition, under high pressures, for example under atmospheric pressure, the operation of the device gives rise to considerable noise levels. At the same time, it is an installation of complicated design considering the use of a magnetic system intended for the rotation of the arc.

 The annular electrode has a small working surface, and due to the wear of the electrode and the fouling of the working surface of the electrode by substances resulting from cleaning, the state of the surface electrode work becomes less good and, consequently, the operating potential of the electrode decreases and the quality of the treatment of the product deteriorates.

 The object of the invention is to create an installation for the treatment of long products with an electric arc, which would make it possible to improve the quality of the treatment of the products thanks to the use of electrodes which are arranged on either side. other of the product and can move relative to this product while being arranged in a vacuum chamber.

 The solution consists in that the installation for the treatment of long products with an electric arc, comprising an electrode located at a given distance from the surface of the product, a source of power for the arc discharge, one terminal is connected to the product by means of a current supply member, and the other terminal of which is connected to the electrode, is characterized, according to the invention, in that it comprises at least one additional source for supplying the arc discharge and at least one additional electrode placed at a given distance from the product and connected to a terminal of said additional source of supply to the arc discharge via a current supply member, while the other terminal of the additional arc discharge power source is connected to the product, and the electrodes arranged on either side of the product are mounted inside of a vacuum chamber and movable relative to the product.

 It is possible to provide in said installation at least one member for cleaning the surface of at least one electrode, which would be fixed to the vacuum chamber with the possibility of coming into contact with the corresponding electrode, would be placed outside the arc gap and would be made in the form of a rod with a tip.

 It is advantageous that each rod end is movable relative to the electrode.

 It is also advantageous to offset the electrodes along the axis of the product.

 It is possible to have a partition forming a screen between the electrodes.

 It is also possible to place two partitions forming screens between the electrodes.

 Provision could be made for fixing the current supply member to at least one of said partitions forming screens.

 One could also place between the partitions forming screens at least one roller contacting the product.

 It is advantageous to connect the roller with the sources supplying the arc discharges.

 It is possible to mount on the rod of the cleaning block of the electrode surface an element intended to initiate the arc discharge.

 It is rational to make the arc discharge initiating element in the form of a cantilever arm.

 It is desirable to produce at least one of the electrodes in the form of a disc mounted on a movable shaft.

 It is possible that at least one of the electrodes is made up of at least two parts clamped against each other and mounted on movable shafts in order to be able to move relative to the product to be treated.

 It is advantageous for the axes of the shafts carrying the electrodes to be parallel and arranged at the same angle relative to the longitudinal axis of the product.

 It is convenient to fix the electrode shafts on the sides of the vacuum chamber in which the inlet and outlet ports are formed for the passage of the product.

 The invention makes it possible to obtain an extremely clean surface on products of great length, for example before application of coatings or during the cleaning of a welding metal wire. Furthermore, it is possible at the same time to heat the product. Up to the prescribed temperature. Heating may be essential, for example, to ensure the drying of the coatings applied to the surface treated by the arc discharge.

The invention will be better understood and other objects, details and advantages thereof will appear better in the light of the explanatory description, which will follow, of various embodiments given solely by way of nonlimiting examples, with references to the accompanying non-limiting drawings in which
- Figure 1 schematically shows an overview of an installation whose electrodes are made in the form of discs and are separated by a partition forming a screen, according to the invention;
- Figure 2 shows a sectional view along
II-II of Figure 1, according to the invention ;;
- Figure 3 shows an overview of an installation whose electrodes are separated by two partitions forming screens, between which is a roller contacting the product, according to the invention;
- Figure 4 shows an external view of a member for cleaning the surface of the electrode, in which are fixed, on a rod, the tip of the member for cleaning the surface of the electrode and l 'arc initiating element, said rod being mounted perpendicular to the axis of the product, according to the invention; ;
- Figure 5 shows an external view of a member for cleaning the surface of the electrode, in which the tip and the arc initiating element are fixed on the same rod, said rod being mounted on along the axis of the product, according to the invention;
- Figure 6 shows an electrode made in two parts clamped against each other in the area of the arc gap, according to the invention;
- Figure 7 shows a view along arrow B of Figure 6, according to the invention;
- Figure 8 shows an overview of an installation whose chamber contains, in the immediate vicinity of the electrode, an arc ignition rod connected to the arc supply source, according to l 'invention,
- Figure 9 shows a view, along arrow A, of the arc initiating rod shown in Figure 8, according to the invention;
FIG. 10 represents an overall view of an installation, the electrode of which is produced in the form of a movable finger disposed perpendicularly to the axis of the product and provided with two members for cleaning the surface of the product, according to the invention;
- Figure 11 shows an overview of an installation whose electrode is made in the form of an endless screw movable in rotation and back and forth, according to the invention;
FIG. 12 represents a member for cleaning the surface of the electrode, produced in the form of a suspension fixed on the rod and which can move, according to the invention,
The installation for treating long products with an electric arc comprises a chamber 1 (FIG. 1) containing the electrodes 3 placed at a given distance from the product 2.

 The studies carried out by the authors have shown that the use of a stationary arc (which does not rotate around the axis of the product) to obtain a good surface treatment, for example in the event of cleaning of a fine metal wire for the removing a lubricant requires the use of a vacuum in the treatment area. On the other hand, if other suitable means are not used, the high energy density of the arc discharge in the electrode spots leads to local melting of the product surface, to sticking of the arc with the melted parts, that is to say the impossibility of carrying out the treatment under normal conditions. Also, the installation according to the invention uses a vacuum chamber 1, the vacuum being created by known means.

 If the cleaning of products, for example metal wires, must be carried out along their entire perimeter, two electrodes3 are used which are placed on either side of the axis of the product 2 to be cleaned.

 The electrodes 3 are wedged on shafts 4 which are mounted so that they can rotate and move longitudinally with respect to their longitudinal axes 5.

 The sources 6 for supplying the arc discharges 7 are connected to the electrodes 3 by means of brushes 8, and to the product 2, by means of a current supply member 9, fixed to a partition forming screen 10. Holes 11 and 12 formed in the end walls of chamber 1 are provided for the passage of product 2.

 The installation is equipped with elements for cleaning the surface of the electrodes, each of which is fixed to the body of the vacuum chamber 1 with the possibility of coming into contact with its electrode 3, is placed outside the interval d arc and is produced in the form of a rod 13 provided with a tip 14. The tip 14 may further in contact with the electrode 3 either constantly or periodically, for example as the state of its work surface.

 The axes 5 of the shafts 4 are parallel and lie at the same angle ff with respect to the longitudinal axis of the product 2. The shafts 4 are fixed to the walls of the chamber 1 which have the orifices II and 12 for the passage of the product 2.

 Figure 2 shows a sectional view along the line II-II of Figure 1. When using two partitions forming screens 10 (Figure 3), at least one roller 15 can be interposed between said partitions. The roller 15 can between connected to the source 6 for supplying arc discharges 7. Furthermore, the axes 5 of the shafts 4 are placed at angles od and p with respect to the longitudinal axis of the product 2.

 In order to simplify the design of the installation, it is advantageous to have on the rod 13 (FIG. 4) an element 16 for initiating the arc discharge. The rod 13 is movable and urged by a spring 17 placed in the bush 18.

 It is possible that the rod 13 (FIG. 5) provided with the end piece 14 and the element 16 is disposed along the axis of the product 2.

 The electrode 3 in FIG. 6) can be produced in two parts, each of which is provided with bars 19 (FIG. 7 immobilized in a mount 20 located on the shaft 4.

The use of the double electrode 3 (FIG. 6) is necessary to rotate one of the mounts 20 with the bars 19 in order to clean them without extinguishing the arc discharge, that is to say without stopping the ins 1 installation.

In other words, the two parts of the electrode 3 rotate in turn by r U e around the axis 5, and during the rotation of each of these two parts the arc discharge does not go out. The frame 20 can contain any appropriate number of bars 19.

 In the installation, object of the present invention, the arc discharge 7 can further be initiated by a rod 21 fixed to the body of the chamber 1 (FIG. 8). The rod 21 carries elements 22 for connection to the power sources 6. The end of the rod 21 has a notch 23 which embraces the product 2. The dashed lines show the positions of the product 2 during the initiation of the arc discharge 7 at the time of the contact between the product 2 and the electrodes 3. In this case, the electrodes 3 are produced in the form of bars and mounted so as to be able to move relative to the product 2.

 FIG. 9 represents a view of the rod 21 according to arrow A of FIG. 8.

 The electrode 3 (FIG. 10) can have the shape of a finger mounted so as to be able to move relative to the product 2. Furthermore, the longitudinal axis of the electrode 3 can be arranged perpendicularly or under a angle to the longitudinal axis of the product 2.

 FIG. 11 schematically represents an electrode 3 produced in the form of an endless screw fixed movably on the shaft 4.

 In another alternative embodiment, the member for cleaning the surface of the electrode 3 (FIG. 12) is in the form of a suspension 24 on which the end piece 14 is fixed. To reduce the friction between the suspension 24 and the shaft 4, provision may be made for the use of a bearing 25. To increase the stability of the suspension 24, the suspension may include a weight 26.

 The operation of the installation is carried out as follows. We start by starting the arc discharges 7 between the electrodes 3 and the product 2 (FIG. 1).

When the product 2 moves, its surface undergoes a treatment of the two cells simultaneously. By moving the electrodes 3 continuously or periodically, their surface is cleaned by means of the nozzles 14 located on the rod 13, $ t which has the effect of renovating the working surface of the electrodes 3 and makes it possible to increase their duration. of life.

If the surface of the electrodes 3 must be cleaned with a cleaning member such as that produced against dementia in FIG. 12, the latter is rotated,
Then the suspension 24 remains mobile and the cleaning of the surface of the electrode 3 is done by the end piece 14. The suspension 24 can be immobilized remain stationary during the rotation of the shaft 4) not only using the weight 26, but also using a magnet or a magnet electrode. The magnets can between arranged either inside the chamber 1, or outside the latter.

 The use of a device for cleaning the surface of the electrodes 3 with a suspension 24 drilled simplifies the design of the installation, especially when there are several electrodes 3 placed in the vacuum chamber 1.

 The use of a partition forming a screen 10 (FIG. 1) between the electrodes 3 eliminates the possibility of mutual irradiation of the electrodes 3 and arc discharges 7 and makes maintenance of the installation simpler. Attaching the current supply member 9 to the screen partition 10 does not require the use of additional construction elements. The fact that the axes 5 of the shafts 4 are arranged at the same angle with respect to to the axis of the product 2 makes it possible to modify the distance between the electrodes 3 and the product 2 gztce to the displacement of the shafts 4 along the axes 5. The fixing of the shafts 4 on the sides of the chamber 1 in which the orifices are formed It and 12 makes it possible, in the presence of the screen partition 10, to simplify the design of the installation. The arrangement of the shafts 4 parallel and at the same angle X with respect to the product 2 makes it possible to synchronously modify the interval between the electrodes thanks to the displacement of the shafts 4 along the axes 5, and creates identical conditions for the surface treatment of the product 2 by carrying out the operation of the two catis, which improves the quality of the cleaning.

 In the body of the chamber 1 can be created, in the area of the arc discharge 7, any desired pressure, for example a vacuum.

 In the case where it is necessary for the axes 5 (FIG. 3) of the shafts 4 to form different angles and 4 with the axis of the product 2, or when the direction of movement of the product 2 in the chamber 1 has to be changed, it is advantageous to place in the body of the chamber 1 two screen partitions 10 (FIG. 3) and to fix the roller 15 therebetween. Furthermore, the roller 15 can serve as an element for supplying current from the sources 6 to the product 2. This makes contact between product 2 and the power source 6 more reliable.

 Since the arc discharge initiating element 16 is essential in any arc discharge installation, it is advantageous to combine it with a member for cleaning the surface of the electrodes to simplify the design of the installation. To this end, the rod 13 (FIG. 4) is fixed with the end piece 14 and the element 16 for initiating the arc discharge. To start the arc discharge, the rod 13 is lowered, the element 16 then applying the product 2 against the electrode 3.

Then, under the action of the spring 17, the rod 13 returns to the initial position and the arc discharge 7 is initiated between the product 2 and the electrode 3. At the same time, the end piece 14 is tightened against the electrode 3. The rod 13 can be mounted at any angle relative to the longitudinal axis of the product 2, for example as shown in FIG. 5. During the rotation of the rod 13 (appearing in cross section on this in the counterclockwise direction, the element 16 applies the product 2 against the electrode 3. Then, when the rod 13 returns to the initial position, the arc discharge 7 starts and the endpiece 14 is clamped against the electrode 3.

 The electrode 3 (Figures 6 and 7) can be in the form of bars at the ends of which ignites the arc discharge 7. When one of these bars operates, the other undergoes cleaning. This embodiment of the electrode in two parts (or more) allows the cleaning of the electrodes 3 without extinguishing the arc discharge 7, that is to say without stopping the installation. In this case, it is possible at any time to rotate only a part (left part or right part in FIG. 6) relative to the axes 5. During this time, the arc discharge 7 remains on between the electrode 3, which is stationary, and produces 2.

 It is possible to start the arc discharge 7 (FIG. 8) using a rod 21 mounted separately and provided with a notch 23. In this case, the power sources 6 are connected to the product 2 via terminals 22 and the rod 21. To start the arc discharge 7, the rod 21 is lowered and mounted. The product 2 being in the notch 23 flexes and comes into contact with the rible with each of the electrodes 3.

Arc discharges 7 then light up between the ends of the electrodes 3 and the product 2. The arrangement of the electrodes 3 in the same plane perpendicular to the longitudinal base of the product 2 simplifies the process of initiating the arc discharges 7.

 The installation according to the invention allows the use of electrodes 3 (Figure 10) in the form of must or electrodes 3 (Figure 11) in the form of a worm.

The use of an electrode 3 in the form of a worm screw considerably increases its service life.

Compared to the electrode 3 in the form of a disc, its service life is as many times greater as there are turns on the worm. The electrode 3 in the form of a worm must be able to rotate and move back and forth so that the arc discharge 7 ignites in the same place and so that it is possible to clean the active surface of the screw In addition to the electrodes 3 indicated above, the installation in accordance with the invention may include electrodes having working surfaces in the shape of an ellipse, a parabola, etc., arranged at different angles relative to the axis of the product 2, or else different electrodes, for example one in the form of a disc (FIG. 1) and the other in the form of a bar (FIG. 8), the cleaning member then being able to stretch arranged only on the electrode disc-shaped.

 In the area of each arc 7, can be treated simultaneously one or more products placed either against each other, or at a certain distance from each other. It is preferable to apply a positive potential to the electrodes 3, but it is also possible to apply a negative potential to them, or alternatively supply them with alternating current.

 The invention makes it possible, during the treatment of the surface of the products, to avoid pollution of the ambient environment, to improve the working conditions and to enhance the quality of the treatment of the products.

 Of course, the invention is in no way limited to the embodiments described and shown which have been given only by way of example. In particular, it includes all the means constituting technical equivalents of the means described as well as their combinations, if these are executed according to the spirit and implemented in the context of protection as claimed.

Claims (15)

 1.- Installation for the treatment of long products with an electric arc, of the type comprising an electrode located at a given distance from the surface of the product to be treated, a Le (6) Arc supply, one terminal of which is connected to said product by means of a current supply member, and the other terminal of which is connected to said electrode, characterized in that it comprises at least one additional source (6) for supplying the arc, and at least one additional electrode (3), placed at a given distance from the surface of the product to be treated (2) and connected to a terminal of said additional arc supply source by means of a current supply member (9), the other terminal of the additional arc supply source being connected to said product, said electrodes being arranged on either side, respectively, of said product and being mounted on the inside a vacuum chamber (1) and so as to be able to move relative to the pro has to deal with.  2.- Installation according to claim 1, characterized in that it comprises at least one member for cleaning the surface of at least one electrode (3), said one or more members being fixed to the body of the vacuum chamber ( 1) with the possibility of coming into contact with the corresponding electrode, each of said members being situated outside the arc discharge interval and being produced in the form of a rod (13) provided with a end cap 14.  3.- Installation according to one of claims 1 and 2, characterized in that each rod (13) with tip (14) is movable relative to the corresponding electrode.  4.- Installation according to one of claims 1, 2 and 3, characterized in that the electrodes (3) are offset along the axis of the product to be treated (2).  5.- Installation according to one of claims 1, 2, 3 and 4, characterized in that a partition forming a screen (10) is disposed between the electrodes.  6.- Installation according to one of claims 1, 2, 3 and 4, characterized in that two partitions forming screens (10) are placed between the electrodes.  7.- Installation according to one of claims 5 and 6, characterized in that on at least one of said partitions is fixed a member (9) for supplying current.  8.- Installation according to one of claims 1, 2, 3, 4, 6 and 7, characterized in that in the space separating the two partitions is mounted at least one roller (15) contacting the product to be treated (2 ).  9.- Installation according to claim 8, characterized in that said roller is connected to the sources (6) of arc supply.  10.- Installation according to one of the preceding claims, characterized in that an element (16) for initiating the arc is mounted on the rod (13) of the member for cleaning the surface of the electrode.  11.- Installation according to one of the preceding claims, characterized in that the element (16) for initiating the arc is produced in the form of an overhanging arm.  12.- Installation according to one of the preceding claims, characterized in that at least one electrode (3) is produced in the form of a disc mounted on a movable shaft.  13.- Installation according to one of the preceding claims, characterized in that at least one electrode (3) consists of at least two parts adjoining one another mounted on movable shafts (4) so to be able to move relative to the product to be treated (2).  14.- Installation according to claim 12, characterized in that the axes of the shafts (4) carrying the electrodes (3) are arranged parallel to each other and at the same angle relative to the longitudinal axis of the product to be treated (2).  15.- Installation according to claim 14, characterized in that the shafts (4) of the electrodes (3) are fixed on the sides of the vacuum chamber (1) in which are formed the inlet and outlet orifices 01) and (12) of the product to be treated (2).