FR2504432A1 - Elongated stock arc treatment appts. - having displaceable electrode elements and magnet system for arc rotation - Google Patents

Abstract

The appts. comprises a housing contg. an electrode consisting of two or more elements secured on the housing and displaceable wrt. the stock, a power source connected to the stock and the electrode, and a magnetic system for rotating the arc in the gap between the stock and the electrode. The appts. is useful for surface cleaning of conductive stock, such as wires, pipes, strip and shafts, to remove scale and grease, as well as for surface hardening and refining of such stock. The use of a displaceable, multi-element electrode gives increased electrode service life (cf. US3211886) and the appts. avoids environmental pollution, improves the quality of the stock being cleaned and is reasonably compact.

Description

 The present invention relates to techniques for using the electric arc and in particular relates to a device for the treatment of long products with the electric arc.

 The invention can be applied to the pickling of electroconductive products, for example in the form of wires, tubes, strips, shafts, shaped profiles, with a view to removing them from scale, manufacturing grease, improving the quality of their surface layer and to refine them, as well as for the reheating of such products.

 One of the current problems in the manufacture and completion of metal products is the treatment of their surface, in particular with a view to removing it from soiling. Widespread pickling methods, such as chemical or mechanical treatment methods, are very often unsatisfactory from the technological point of view and from that of environmental pollution.

 It is advantageous to use for stripping the surface of metals or other electrically conductive materials an arc discharge initiated between the product to be treated and an electrode.

 A device is known (US Patent No. 3,211,886, cl. 219-123, published in 1965) for the treatment of long products with an electric arc, comprising a body in which is placed an electrode surrounding the product. The device also includes a source of arc supply ~ connected to the product and the electrode, as well as a magnetic system for the rotation of the arc in the distance between the product and the electrode, this system being placed at a predetermined distance from the electrode. The electrode is cooled.

When this device is operating, process gas is admitted to the area of the rotating electric arc from opposite sides of the device.

 This known device does not ensure a sufficiently long service life of the electrode, owing to the limited extent of its active surface. Maintenance of the device is complicated, since access to the active surface of the electrode, for example to clean it, is practically impossible. In addition, the rotating electric arc, blown by a stream of pressurized gas, produces considerable noise.

 To change the extent of the active surface of the electrode, it is necessary, in this known device, to mount a new electrode.

 The object of the invention is to create a device for the treatment of long products with an electric arc, which would make it possible to increase the service life of the electrode thanks to a new design of it, making it possible to vary the extent of its active surface without replacing it.

 This object is achieved by the fact that the device for the treatment of long products with an electric arc, of the type comprising a body inside which is placed an electrode surrounding the product, a power source of the arc connected to the product to be treated and to the electrode, as well as a magnetic system for the rotation of the arc in the distance between the product and the electrode, this system being placed at a predetermined distance from the electrode, is characterized, according to the invention, in that the electrode is produced in at least two parts fixed to said body so that they can move relative to the product.

 Each part of the electrode can be produced in the form of a wheel whose axis of rotation is perpendicular to the longitudinal axis of the product.

 Each part of the electrode can also be produced in the form of a wheel whose axis of rotation is parallel to the longitudinal axis of the product.

 It is wise to give the cross section of each wheel, perpendicular to its axis of rotation, the shape of a circle, a polygon or any other suitable geometric figure.

 It is preferable to arrange the axes of rotation of said parts of the electrode so that they are mutually parallel.

 It is advantageous that the axis of rotation of at least one of said parts of the electrode is arranged perpendicular to the axes of rotation of its other parts.

 It is preferable that the axis of rotation of at least one of the parts of the electrode is arranged at an angle with respect to the axes of rotation of its other parts.

 It is possible to mount each of said parts of the electrode so that its axis of rotation coincides with its axis of symmetry.

 It is also possible to mount each of said parts of the electrode so that its axis of rotation is at a predetermined distance from its axis of symmetry.

 It is advantageous that at least the axis of rotation of one of said parts of the electrode is placed in coincidence with its axis of symmetry.

 It is also possible to coincide the longitudinal axis of the product and the axis of symmetry of the active surface of the electrode.

 It is also possible to make the electrode so that the displacements of all its parts are in the same direction.

 It is possible to make the electrode so that at least one of its parts moves against its other parts.

 The application of the device for the treatment of long products to the electric arc, which is the subject of the invention, makes it possible in particular to eliminate pollution of the ambient environment and to raise the quality of the products treated, while using sufficiently compact equipment.

The invention will be better understood and other objects, details and advantages thereof will appear more clearly in the light of the explanatory description which will follow of different embodiments given solely by way of nonlimiting examples, with references to the drawings. nonlimiting annexed in which
- Figure 1 shows an overview of a device for the treatment of long products with an electric arc (section perpendicular to the longitudinal axis of the product), in which the axes of rotation of the parts of the electrode are perpendicular to the longitudinal axis of the product, according to the invention;
- Figure 2 shows a section along Il-Il of Figure 1, according to the invention ;;
- Figure 3 shows an overall view of a ### device for the treatment of long products with an electric arc (section perpendicular to the longitudinal axis of the product), in which the axes of rotation of the parts of the electrode are parallel to the longitudinal axis of the product, according to the invention;
- Figure 4 shows a section along IV-IV of Figure 3, according to the invention;
- Figure 5 shows an external view of a device for the treatment of long products with an electric arc, in which the axes of rotation of the parts of the electrode are arranged at an angle o relative to the longitudinal axis of the product according to the invention
- Figures 6 and 7 show possible variants of the shape of the cross section of the electrode parts, according to the invention; ;
- Figure 8 shows an overall view of the electrode in section perpendicular to the longitudinal axis of the product, in the case where the axis of rotation of at least one of the parts of the electrode is arranged perpendicularly to the axes of rotation of the other parts of the electrode, according to the invention;
- Figure 9 shows an external view of the electrode in section perpendicular to the longitudinal axis of the product, in the case where the axis of rotation of at least part of the electrode is arranged at an angle ft relative to to the axes of rotation of its other parts, according to the invention;
- Figure 10 shows an external view of one of the parts of the electrode, in the case where its axis of rotation coincides with its axis of symmetry, -from the invention;
- Figure 11 shows a sectional view along
XI-XI of Figure 10, according to the invention;
- Figure 12 shows an external view of one of the parts of the electrode in the case where its axis of rotation is at a predetermined distance from its axis of symmetry, according to the invention;
- Figure 13 shows a sectional view along
XIII-XIII of Figure 12, according to the invention;
- Figures 14, 15, 16, 17, 18, 19 show alternative arrangements of two adjacent parts of the electrode (sectional view parallel to the axes of rotation of these parts), according to the invention;
- Figure 20 shows an external view of the electrode in the case where the axis of the product is at a predetermined distance from the axis of symmetry of the active surface of the electrode, according to the invention;
- Figure 21 shows an alternative embodiment of the electrode with a number of parts equal to the number of sides of the product to be treated, according to the invention;
- Figure 22 shows an external view of an electrode consisting of six parts, together with a cleaning subassembly of its active surface, produced in the form of a ferrule, according to the invention;
- Figure 23 shows an external view of the sub-assembly for fixing a cleaning element to the shell, according to the invention;
- Figure 24 shows an overview of the cleaning sub-assembly in the case where the cleaning element corresponds to the profile of the active surface of the electrode.

 The device for treating long products with an electric arc comprises a body 1 (FIG. 1), inside which is placed an electrode surrounding the product 2. The electrode consists of parts 3 which are fixed on rods 4 mounted in the body I so that they can move relative to the product 2. The device further comprises a source 5 of arc supply, connected to the product 2 and to the electrode, as well as a magnetic system, for example in the form of a coil 6, generating a magnetic field which ensures the rotation of the arc 7 in the distance between the electrode and the product 2. The power source 5 is connected to the product 2 using conductive rollers 8 (Figure 2), and to the rods 4 of the electrodes, using brushes 9 (Figure 1). Each part 3 of the electrode is produced in the form of a wheel, the axis 10 of rotation of which is perpendicular to the longitudinal axis of the product 2.

 It is possible to produce a variant of the device, in which each part 3 (FIG. 3) of the electrode is a wheel whose axis of rotation 10 is parallel to the longitudinal axis of the product 2.

Figure 4 shows a following sectional view
IV-IV of figure 3.

 In addition, each part 3 (FIG. 5) of the electrode can be produced in the form of a wheel whose axis of rotation is arranged at an angle 0t with respect to the longitudinal axis of the product 2.

 Figures 6 and 7 show possible variants of cross section shape of the rollers.

 FIG. 8 represents an overall view of a device for treating long products with an electric arc in the case where the axes 10 of rotation of two parts 3 of the electrode are perpendicular to the axes 10 of rotation of the other two parts 3 of the electrode.

FIG. 9 represents a variant in which two adjacent parts 3 of the electrode and their rods 4 are arranged at an angle
Figures 10 and II show an alternative embodiment of part 3 of the electrode, in which the axis 10 of rotation of this part coincides with its axis II of symmetry.

 Figures 12 and 13 show an alternative embodiment of a part 3 of the electrode, in which the axis 10 of rotation of this part is at a distance h from its axis Il of symmetry.

 Figures 14, 15 16, 17, 18, 19 each show a different variant of arrangement of adjacent parts 3 of the electrode.

 The longitudinal axis of product 2 (figure 1, 2, 3 or 4) can either coincide with the axis of symmetry of the active surface of the electrode, or be at a distance from it (figure 20) .

 By "active surface" of the electrode is meant its surface on which the arc is struck at the instant considered.

 The number of parts 3 of the electrode can be equal to the number of sides of product 2 (figure 2.1) to be treated.

 The device can be equipped with a sub-assembly for cleaning the surface of the parts 3 of the electrode. This sub-assembly includes cleaning elements 12 (FIG. 22) mounted in a ferrule 13. The ferrule 13 is fixed to the body 1 by a fixing element 14.

 The cleaning elements 12 (FIG. 23) can be pushed by springs 15 ensuring their tightening against the parts 3 of the electrode. The cleaning elements 12 can also be rigidly positioned with respect to the parts 3 of the electrode.

 The profile of the section of the active part of the cleaning elements 12 (FIG. 24) preferably corresponds to the shape of the part 3 to be cleaned of the electrode.

 The device operates as follows.

 The power source 5 (Figure 1) being connected, an electric arc 7 strikes between the product 2 and the electrode. Under the effect of the magnetic field of the coil 6, this arc 7 is rotated around the product 2.

 The parts 3 of the electrode are mounted so that they can move relative to the product 2, so that after each movement, the arc 7 strikes on new portions of their active surface.

 The treatment of the surface of product 2 with an electric arc is carried out, as a rule, with a negative potential applied to product 2 and a positive potential applied to the electrode. However, the device can also operate with a positive potential applied to the product2 and a negative potential applied to the electrode, as well as with supply of the arc by an alternating voltage.

 The extent of the active surface of all the parts 3 (FIG. 1) of the electrode is greater than that of the surface of the electrode on which the arc 7 is struck at any given time. All other conditions being equal (power of the arc, speed of movement of the product, etc.), the service life of the electrode will be as many times greater than the total active surface of parts 3 of the electrode is larger than the surface on which the arc 7 is struck at any given time. The use of the cleaning elements 12 (FIG. 22) makes it possible to maintain the surface of the electrode in the desired state.

 The use of the device for the treatment of long products with an electric arc according to the invention is particularly effective when the vacuum prevails inside the body 1 (FIG. 1). In this case, the energy density of the arc 7 is lower, the effort required to tear off the dirty layer of the base metal of the product 2 to be treated is lower, the treatment becomes more uniform thanks to the lowering of the energy density of arc 7, the noise inevitably accompanying arc 7 when it is struck in air under normal pressure disappears completely.

 During the operation of the device for the treatment of long products with an electric arc, the rollers can rotate either in the same direction, or in opposite directions. If the speed of rotation of the knobs is chosen to be of a value such that the vectors of the linear speeds of movement of their active points relative to product 2 (Figure 1) are equal and in opposite directions, maintaining the rotating arc 7 in position compared to product 2 will be better, that is to say that the arc 7 will not be driven by product 2 or by the knobs. The same effect will be obtained if the knobs rotate in opposite directions at the same speed in the case of the treatment of a stationary product 2, or else at different speeds in the case of the treatment of a product 2 in movement.

 The arrangement of the axes 10 of rotation of the parts 3 of the electrodes so that they are all perpendicular to the longitudinal axis of product 2 (FIG. 1 or 2) or else all parallel to the longitudinal axis of product 2 (FIG. 3 or 4) depends on the concrete parameters of the treatment (diameter of product 2, speed of travel of product 2, shape of section of product 2) as well as the number of electrodes mounted along the length of product 2.

Thus, for example, the embodiment of the electrode according to FIGS. 1 and 2 makes it possible to place in one body 1 two or more of two electrodes, since the rods 4 carrying the electrode and, consequently, the current leads 9 , are released on the lateral surface of the body 1. On the contrary, if the technical conditions are such that the use of a single electrode is sufficient, the variant represented by FIGS. 3 and 4 can be applied. In this case , the rods 4 and the current leads 9 are released on the front walls of the body 1.

 it is also possible to produce the electrode in several parts 3 (FIG. 8), according to a variant in which the axes 10 of rotation of two parts 3 of the electrode placed opposite are arranged parallel to each other and perpendicularly to the axes 10 of rotation of the other two parts 3 of the electrode, also placed opposite.

 An advantage of such a mode of treatment of the product 2 consists in that it is carried out with self-cleaning of the parts 3 in rotation in the zone where they come into contact.

This makes it possible to reduce the number of cleaning elements 12 (FIG. 22) mounted outside the initiation zone of the arc 7, or even to eliminate them.

 In a series of cases, for example when the power of the device is relatively high, fixing the rods 4 (FIG. 1) to the walls of the body 1, installing the drive sub-assemblies, insulators (the sub-assemblies of 'drive and insulators are not shown in the drawings) of the current leads 9, requires a fairly large space, so it is more advantageous to have the rods 4 at a certain angle # p (Figure 9).

 The shape of the straight section of the rollers (Figures 6, 7, 10, 11, 14, 15, 16, 17, 18 or 19), as well as the character of their contact, are conditioned by the profile and the dimensions of the section of the product 2 to be treated, the volume of the body 1, the power of the device, the method of cooling the electrodes and their dimensions.

In the case where the parts 3 (FIGS. 4, 14) of the electrode come into contact, the use of a current supply 9 (FIG. 4) on each rod 4 is not compulsory. The electric current can then be transmitted by the contact of the parts 3 between them.

 In the case where the same device has to process products 2 of different sections, the diameter of the active surface of the electrode can be modified without changing the electrode. If the device is produced according to FIG. 3, this can be obtained by moving the axis 10 (FIG. 13) of rotation of the part 3 of the electrode with respect to the axis of symmetry 11 by the required value h.

Such an embodiment of the parts 3 of the electrode is also possible for compensating for the wear of the active surface of the electrode.

 The change in the diameter of the active surface of the electrode can also be obtained by producing a groove with variable profile on the active surface of the parts 3 of the electrode, for example in the form of a semicircle of radius r (FIG. 1) .

 For certain products 2, it may prove necessary to carry out the treatment with a rotating arc 7 so as to confer on their surface different properties according to their perimeter, for example different roughnesses. In this case, the product 2 is offset relative to the axis of symmetry of the electrode at the distance S (FIG. 20). The arc being rotated by the magnetic field, its length varies, so its parameters (arc current, arc voltage, that is to say the power of the arc) also vary. it follows that the level of thermal action at various points of the perimeter of product 2 is different, and it is therefore possible to obtain the required properties, which vary depending on the perimeter of product 2.

 it should be noted that the treatment of the surface of the product 2 so as to give it a prescribed irregularity can be carried out by placing the product to be treated 2 (FIG. 5) at an angle CE relative to the axis of rotation of the parts 3 of the electrode.

 In a series of cases, for example to maintain a constant spacing between the product 2 and the active surface of the electrode, it is advantageous to choose a number of parts 3 of the electrode equal to the number of sides of the product to be treated 2 (figure 21).

 During the operation of the device, the active surfaces of the parts 3 of the electrode undergo a certain wear and tear and are clogged with the products of the treatment. it results in an alteration of the arc stability and, consequently, an alteration in the quality of the treatment. To eliminate fouling, it is advantageous to clean the active surface of the parts 3 (FIG. 22) outside the operating zone of the arc 7. The cleaning elements 12 of each part 3 can have individual fasteners attaching them to the body 1. However, if the number of parts 3 of the electrode is large, such a solution complicates the design of the device and alters the external appearance of the body 1. A more advantageous solution consists in fixing the cleaning elements 12 in a ferrule 13, which is fixed to the body 1 by a fixing element 14. The cleaning elements 12 themselves can be fixed in the shell 13 either rigidly or using a spring 15 (FIG. 23). The profile of the section of the cleaning element 12 can correspond to the profile of part 3 (FIG. 24) of the electrode.

 it should be noted that in the case where the parts 3 (figure 21) of the electrode are placed in a common plane, to change the surface of the electrode working in the area of the arc 7, it is necessary to move the part 3 along the longitudinal axis 10 (Figure 21), turn it 90 around this axis, then return it to its initial position.

 The use of the device proposed for the treatment of long products with an electric arc makes it possible to raise the quality of the products treated, to eliminate pollution of the ambient environment.

 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 its spirit and implemented within the framework of protection as claimed.

Claims (13)

 1.- Device for the treatment of long products with an electric arc, of the type comprising a body inside which is placed an electrode surrounding the product to be treated, a power source of the arc connected to the product and to the electrode, as well as a magnetic system for the rotation of the arc in the distance between the product and the electrode, this system being placed at a distance prI & termde delteRsizodecharacterized in that the electrode is made in au at least two parts (3) fixed to said body so that they can move relative to the product to be treated (2).  2.- Device according to claim 1, characterized in that each part $$ of the electrode is made in the form of a wheel whose axis of rotation (10) is perpendicular to the longitudinal axis of the product (2 ).  3.- Device according to claim 1, characterized in that each part (3) of the electrode is made in the form of a wheel whose axis of rotation (10) is parallel to the longitudinal axis of the product  4.- Device according to one of claims 1 to 3, characterized in that the cross section of each wheel (3) perpendicular to the axis of rotation of this has the shape of a circle, a polygon or any other appropriate geometric figure.  5.-Device according to one of claims 1 to 4, characterized in that the axes of rotation (10) of the parts (3) of the electrode are arranged parallel to each other.  6.- Device according to one of claims 1 to 4, characterized in that the axis of rotation (10) of at least one of the parts (3) of the electrode is arranged perpendicular to the axes of rotation ( 10) of its other parts (3).  7.- Device according to one of claims 1 to 4, characterized in that the axis of rotation of at least one of the parts (3) of the electrode is disposed at an angle p relative to the axes of rotation of its other parts.  8.- Device according to one of claims 1 and 4, characterized in that the axis of rotation (10) of each of the parts (3) of the electrode coincides with its axis of symmetry (11).  9.- Device according to one of claims 1 and 4, characterized in that the axis (10) of rotation of each of the parts (3) of the electrode is at a predetermined distance from its axis of symmetry (11 ).  10.- Device according to one of claims 1 and 4, characterized in that at least the axis of rotation of one of the parts (3) of the electrode coincides with its axis of symmetry (11).  11.- Device according to claim 1, characterized in that the longitudinal axis of the product (2) coincides with the axis of symmetry of the active surface of the electrode.  12.- Device according to one of claims 1 to 11, characterized in that the directions of movement of all the parts (3) of the electrode are the same.  13.- Device according to one of claims 1 to 11, characterized in that at least one of the parts (3) of the electrode has a direction of displacement opposite to that of its other parts (3).