EP2868779B1 - Device and method for cleaning and/or polishing workpieces - Google Patents

Description

The invention relates to a device for cleaning and / or polishing workpieces, in particular of welds on the inside of tubular workpieces, according to the closer defined in the preamble of claim 1. Art Furthermore, the invention relates to a method for cleaning and / or polishing workpieces , In particular of welds on the inside of tubular workpieces, according to the closer defined in the preamble of claim 9.

In the production of welded joints very high temperatures occur, which often lead to discoloration or impurities, especially in the immediate area of the weld. These impurities are removed according to a known prior art, for example by the so-called tampon process, in which a felt is placed around a rigid electrode and a current from the electrode previously wetted by a current flows from the electrode into the workpiece. In this electrochemical process, the electrons forming the workpiece pass on the electrode and are thus removed from the workpiece.

Furthermore, it is generally known to use brushes equipped with carbon fibers, which work according to a fundamentally similar principle. With such brushes, however, no or only a very complex and insufficient cleaning of internal parts, such as holes, pipes or the like, possible because the long fibers of the brush bend uncontrollably, so that the fiber ends no longer perpendicular to the workpiece to be cleaned incident. As a result, due to the physical property of the carbon fiber to be a very poor conductor in the transverse direction, only a very small amount of current flows and no arcing occurs at the tips of the carbon fibers. Apart from the fact that the inner diameter of tubular components with such brushes are very difficult to achieve, this also results in a very poor cleaning effect.

From the AU 2008 101 064 A4 a device for electrochemical cleaning and etching of metals is known. In this case, membranes and felts are arranged around a rigid electrode, wherein a carbon fiber membrane serves as an intermediate layer between the electrode and the felt.

The JP H02 205700 A describes an apparatus for cleaning the inner surface of pipes comprising an electrode cover made of polyester fibers.

It is therefore an object of the present invention to provide an apparatus and a method for cleaning and / or polishing workpieces, in particular welds on the inside of tubular workpieces, which allow a simple and reliable cleaning.

According to the invention, this object is achieved by the features mentioned in claim 1.

By aligning the carbon fibers of the device according to the invention in a direction perpendicular to the longitudinal axis of the central support member ensures that always impinge the tips of the carbon fibers on the workpiece to be cleaned, so that a very high current flows, which generates arcs at the tips the carbon fibers is sufficient, whereby the cleaning performance is significantly enhanced. Here, the existing of an electrically conductive material or at least one conductive material having holding element serves as an electrode through which the of Power source generated, relatively high current flows at relatively low voltage, wherein a closed circuit is generated by the connection of the power source to the workpiece via the holding member and the carbon fibers.

The holding element according to the invention is made elongated and the carbon fibers are arranged around a substantial part of the circumference thereof, so that inner areas of workpieces, such as pipes, holes or depressions of any kind, can be electrochemically cleaned or polished in a very simple manner. The inventive arrangement of the carbon fibers on the holding element is also achieved that the largest possible number of carbon fibers is applied simultaneously to the surface of the workpiece, so that a very high cleaning performance can be achieved. This ultimately shortens the duration of the cleaning process for a single workpiece, thereby reducing manufacturing costs.

In a very advantageous development of the invention can be provided that the carbon fibers are arranged around the entire circumference of the holding element. This ensures that even with a purely linear movement of the device relative to the workpiece, d. H. during a movement of the holding element in the direction of the longitudinal axis of the same, all surface areas of the workpiece are touched by the current-carrying carbon fibers.

A manufacturing technology relatively simple to implement embodiment of the invention may consist in that the holding element has at least two multiple mutually twisted wire sections, between which the carbon fibers are jammed. This also allows a uniform distribution of the carbon fibers around the circumference of the holding element.

Alternatively, however, it can also be provided that the carbon fibers are held as bundles in respective recesses of the holding element. In this way, the distribution of the carbon fibers can be adapted to specific applications.

Alternatively, it can also be provided that the carbon fibers are arranged in an annular manner around a holding element designed as a securing ring. In this way, a Kohlefaserbesatz with any variable or variable outer diameter, since the same can be determined by the fiber length and the diameter of the locking ring.

In a further alternative embodiment of the invention, if the carbon fibers are arranged side by side in the longitudinal direction and held by means of the holding element, the result is a carbon fiber stock of any length.

In order to prevent that when using the device according to the invention by a contact of the workpiece with the current-carrying holding element may cause a short circuit, can be provided in a further advantageous embodiment of the invention that the holding element in at least one region along its longitudinal axis, in which no Carbon fibers are provided, having an electrical insulating element.

A further advantageous embodiment of the invention may consist in that the holding element has an electrical insulating element in at least one region along its longitudinal axis, in which carbon fibers are provided. In this way, with a wear-related shortening of the carbon fibers nevertheless ensures that the holding element can not come into contact with the workpiece, so that short circuits are excluded.

Furthermore, the holding element may have an electrical insulating element in a front end region. Such an insulating element in the front end region of the holding element is particularly advantageous when using the device according to the invention in workpieces which have a bottom, since even then a short circuit is avoided.

Alternatively or possibly additionally, it may be provided that the holding element has in a front end region a plurality of carbon fibers extending at different angles with respect to the longitudinal axis of the holding element, which are firmly connected to the holding element. By means of such provided in the front end region of the holding element carbon fibers, a cleaning or polishing is achieved even with components with a bottom.

A procedural solution of the problem results from the features of claim 11.

The inventive method can be achieved in a very simple and reliable way, a cleaning and / or polishing even the otherwise difficult to access inner sides of tubular workpieces.

An improvement in the cleaning performance can be achieved if the holding element is moved relative to the workpiece.

Embodiments of the invention are shown in principle with reference to the drawings.

Fig. 1

eine schematische Darstellung der erfindungsgemäßen Vorrichtung zum Reinigen und/oder Polieren von Werkstücken;

Fig. 2

eine Seitenansicht einer vergrößerten Darstellung des Halteelements mit den daran angebrachten Kohlefasern;

Fig. 3

eine Vorderansicht einer weiteren Ausführungsform der erfindungsgemäßen Vorrichtung;

Fig. 4

eine Vorderansicht einer weiteren Ausführungsform der erfindungsgemäßen Vorrichtung;

Fig. 5

einen Schnitt durch eine weitere Ausführungsform der erfindungsgemäßen Vorrichtung;

Fig. 6

eine Seitenansicht einer weiteren Ausführungsform der erfindungsgemäßen Vorrichtung; und

Fig. 7

eine Seitenansicht einer weiteren Ausführungsform der erfindungsgemäßen Vorrichtung;

It shows:

Fig. 1

a schematic representation of the device according to the invention for cleaning and / or polishing workpieces;

Fig. 2

a side view of an enlarged view of the holding member with the attached carbon fibers;

Fig. 3

a front view of another embodiment of the device according to the invention;

Fig. 4

a front view of another embodiment of the device according to the invention;

Fig. 5

a section through a further embodiment of the device according to the invention;

Fig. 6

a side view of another embodiment of the device according to the invention; and

Fig. 7

a side view of another embodiment of the device according to the invention;

Fig. 1 shows a device 1 for cleaning and / or polishing workpieces 2. Basically, the device 1 for a variety of workpieces 2 is suitable, but in particular for cleaning and / or polishing a in Fig. 1 Furthermore, in the present case, a tubular workpiece 2, on the inside or inside diameter of which the weld seam 3 to be cleaned or polished is located, is shown very schematically. As will become apparent below, the device 1 is particularly adapted for cleaning and / or polishing such tubular workpieces 2.

The device 1 has a central, elongated retaining element 4, which consists of an electrically conductive material. The holding element 4 serves as explained in more detail below, as an electrode and should, in addition to the electrical conductivity, have a high corrosion resistance to acids. For this purpose, the holding element 4, for example, consist of one of the materials with the material numbers 1.4401, 1.4571, 1.4301 or other preferably high-alloy materials or these materials have at least a predominant part.

The holding element 4 serves in addition to its function as an electrode also to hold a plurality of carbon fibers 5. The carbon fibers 5 are fixedly connected to the holding element 4 in such a way that they run away from the holding element 4 perpendicular to the longitudinal axis x of the holding element 4. The carbon fibers 5 are thus attached to the support member 4 so that they impinge as perpendicular to the surface to be cleaned of the workpiece 2, whereby the property of the carbon fiber to have the best electrical conductivity in the longitudinal direction, is best used. In order to be able to achieve the largest possible range of the inner diameter of the tubular workpiece 2, the carbon fibers 5 are furthermore arranged around a substantial part of the circumference of the holding element 4. In the illustrated embodiments, the carbon fibers 5 are provided in each case around the entire circumference of the holding element 4, but in principle it would also be possible to dispense with the carbon fibers 5 in certain sections around the circumference of the holding element 4. Furthermore, the carbon fibers 5 are arranged on the holding element 4 such that as many carbon fibers 5 as possible touch the surface of the workpiece 2 in the most uniform manner possible.

The device 1 further comprises a current source 6 which is connected on the one hand to the holding element 4 and on the other hand to the workpiece 2. The current source 6 can be operated, for example, with 230 or 400 volts and preferably generates a current with a relatively high current in a line 7 extending from the current source 6 to the holding element 4, the holding element 4, the workpiece 2, one of the power source 6 to the workpiece 2 extending line 8 and the power source 6 itself formed circuit. While the lead 8 is attached to the workpiece 2 by means of a ground terminal 9, the lead 7 is fixed from the current source 6 to the support member 4 to a handle 10 attached to and forming part of the support member 4, and in this way both mechanically and electrically connected to the holding element 4. Thus, a current flows via the holding element 4 and the carbon fibers 5 into the workpiece 2 by the electrical voltage generated in the current source 6 in a controlled manner. The carbon fibers 5 can be connected as an anode or cathode and supplied with a direct current or an alternating current.

In order to remove the impurities present in the region of the weld seam 3 from the workpiece 2, the holding element 4 is brought into contact with the workpiece 2 by the carbon fibers 5 held by it or introduced into the recess of the workpiece 2 in the illustrated embodiment.

Previously, an electrolyte is applied to the workpiece 2 and / or the carbon fibers 5 in order to improve the electrical conductivity. In the case of material removal from the workpiece 2, this is connected as a cathode and electrodes flow from the workpiece 2 to the carbon fibers 5 acting as an anode. In this operating mode, the circuit is supplied with direct current. In the case of the operation of the circuit with alternating current cathode and anode alternate constantly and the impurities are only detached from the surface of the workpiece 2.

If, as indicated above, an arc arises at the end of the carbon fibers 5 due to a corresponding current intensity and due to the substantially vertical impact of the carbon fibers 5 on the workpiece, very high temperatures result, with which a chemical cleaning effect is achieved together with the electrolyte ,

Fig. 2 shows an enlarged view of the device 1, in which substantially the holding element 4 and the attached carbon fibers 5 are shown. In the presentation of Fig. 2 It can be seen that the holding element 4 has two multi-twisted wire sections 4a and 4b, between which the carbon fibers 5 are clamped. For example, the carbon fibers 5 may be adhered to the holding member 4 by bending a wire at 180 ° into a U-shape so that the two legs of the U form the two wire portions 4a and 4b, the carbon fibers 5 between them two wire sections 4a and 4b inserted and then the two wire sections 4a and 4b are rotated against each other. As a result, the holding element 4 clamps the carbon fibers 5 so firmly that they withstand a mechanical stress and good electrical conductivity is ensured by the holding element 4 to the carbon fibers 5. The carbon fibers 5 are thus arranged rotationally symmetrical about the holding element 4 forming the electrode.

Furthermore, in Fig. 2 recognizable that the holding element 4 in several areas along its longitudinal axis x, in which no carbon fibers 5 are provided, an electrical insulating element 11 has. The electrical insulating elements 11, one of which is also provided in the front end region of the holding element 4, serve to prevent a short circuit, which could occur when the holding element 4 comes into contact with the workpiece 4. The electrical insulating elements 11 are preferably made of a heat and acid resistant material, such as polytetrafluoroethylene (PTFE), silicone or other suitable material, or have this at least for the most part. Preferably, the electrical insulation elements 11 are distributed so that all exposed metal parts of the support member 4 are covered by the same.

The length of the carbon fibers 5 may vary depending on the inner diameter of the workpiece 2 to be cleaned. Furthermore, that too Retaining element 4 have a different shape than the illustrated, straight shape and are particularly adapted to the shape of a workpiece 2 to be cleaned. In particular, the holding element 4 can be bent by any angle and / or radii in order to be better adapted to the geometry of the workpiece 2.

Furthermore, in the embodiment of the holding element 4 or the device 1 according to Fig. 2 in an area of the holding member 4 in which the carbon fibers 5 are provided, an electric insulating member 11 is also arranged. This electrical insulating member 11 between the carbon fibers 5 serves to prevent a short circuit when the carbon fibers 5 have become shorter due to wear. Of course, several of these electrical insulating elements 11 may be provided in the stocked with the carbon fibers 5 area.

Fig. 3 shows a front view of an alternative embodiment of the support member 4, in which the carbon fibers 5 are pressed as a carbon fiber bundle 5a in respective recesses 12 of the support member 4 and are held in any other way in the recesses 12. Also in this embodiment, the electrical insulating elements 11 may be provided in the region of the retaining element 4. Furthermore, the handle 10 which is also present in this case can in turn be connected to the power source 6 and an electrical connection can be provided from the handle 10 through the retaining element 4 to the carbon fibers 5. In this case, the holding element 4 does not have to be made entirely of the electrically conductive material, but only an electrically conductive material has to be present within the holding element 4. The outer region of the holding element 4 may be made of a material which is used in the other embodiments for forming the electrical insulating elements 11.

In the embodiment of Fig. 4 the carbon fibers 5 are arranged in a ring around the holding element 4 designed as a securing ring, resulting in a carbon fiber stock having any desired and / or variable outer diameter, since the same can be determined by the fiber length and the diameter of the securing ring 4 forming the retaining ring. While in the embodiment of the device 1 according to Fig. 2 Thus, both ends of the carbon fibers 5 look out on both sides of the support member 4, is in the embodiment of Fig. 4 the length of the carbon fibers 5, however, only the distance between the retaining ring and the outer tip of the carbon fibers. 5

Fig. 5 shows a section through a further embodiment of the device 1, in which the carbon fibers 5 in the longitudinal direction next to each other, that is arranged in a direction perpendicular to the plane of the page, and held by means of the elongated in this case, strip-shaped support member 4. The holding element 4 can have any length, so that in principle any number of carbon fibers 5 can be attached to the same.

The embodiment of the device 1 according to Fig. 6 that is a development of the embodiment of Fig. 2 represents, at a front end of the holding member 4 instead of an electrical insulating 11 more, at different angles to the longitudinal axis x of the support member 4 extending from the same away carbon fibers 5. In other words, in the front region of the holding element 4 carbon fibers 5 are also provided in this case, which can be used, for example, when the workpiece 2 has a bottom, not shown, or it is a blind or blind hole. A similar embodiment of the device 1 is also in Fig. 7 shown.

Claims (12)

1. Device (1) for cleaning and/or polishing workpieces (2), in particular welds (3) on the inner side of tubular workpieces (2), comprising a central, elongated holding element (4) of an electrically conductive material, comprising a multiplicity of carbon fibres (5), which are securely connected to the holding element (4) in such a way that they run away from the holding element (4) perpendicularly in relation to a longitudinal axis (x) of the holding element (4), the carbon fibres (5) being arranged around a large part of the circumference of the holding element (4), and comprising a power source (6), which is connected on the one hand to the holding element (4) and on the other hand to the workpiece (2).
2. Device according to Claim 1,
   characterized in that
   the carbon fibres (5) are arranged around the entire circumference of the holding element (4).
3. Device according to Claim 1 or 2,
   characterized in that
   the holding element (4) has at least two sections of wire (4a, 4b) twisted a number of times with respect to one another, between which the carbon fibres (5) are clamped.
4. Device according to Claim 1 or 2,
   characterized in that
   the carbon fibres (5) are held as clusters in respective recesses (12) in the holding element (4).
5. Device according to Claim 1 or 2,
   characterized in that
   the carbon fibres (5) are arranged annularly around a holding element (4) formed as a retaining ring.
6. Device according to Claim 1 or 2,
   characterized in that
   the carbon fibres (5) are arranged next to one another in the longitudinal direction and are held by means of the holding element (4).
7. Device according to one of Claims 1 to 6,
   characterized in that
   the holding element (4) has an electrically insulating element (11) in at least one region along its longitudinal axis (x), in which no carbon fibres (5) are provided.
8. Device according to one of Claims 1 to 7,
   characterized in that
   the holding element (4) has an electrically insulating element (11) in at least one region along its longitudinal axis (x), in which carbon fibres (5) are provided.
9. Device according to one of Claims 1 to 8,
   characterized in that
   in a front end region the holding element (4) has an electrically insulating element (11).
10. Device according to one of Claims 1 to 9,
    characterized in that
    in a front end region the holding element (4) has a number of additional carbon fibres (5), which extend away from the holding element (4) at different angles with respect to the longitudinal axis (x) thereof and are securely connected to the holding element (4).
11. Method for cleaning and/or polishing workpieces (2), in particular welds on the inner side of tubular workpieces (2), wherein an electrical voltage is applied to a central, elongated holding element (4) of an electrically conductive material, to which a multiplicity of carbon fibres (5) are securely connected in such a way that the carbon fibres (5) run away from the holding element (4) perpendicularly in relation to a longitudinal axis (x) of the holding element (4), the carbon fibres (5) being arranged around a large part of the circumference of the holding element (4), wherein an electrolyte is applied to the workpiece (2) and/or to the carbon fibres (5), and wherein the holding element (4) is brought into contact with the workpiece (2).
12. Method according to Claim 11,
    characterized in that
    the holding element (4) is moved in relation to the workpiece (2).

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