Machine for localised cleaning with electrolytic and/or ultrasound cell, for pickling and/or polishing

ES 2 284 536 T3

DESCRIPTION

Machine for localized cleaning with electrolytic and / or ultrasound cells for pickling and / or polishing.

The invention refers to: a machine for localized cleaning with an electrolytic and / or ultrasound cell for pickling and / or polishing, and also to a machine that is used to clean metal parts in which previous processes have left scabs, halos and in general dirt on metal surfaces; It is very useful for cleaning weld seams.

The prior art comprises machines that are designed to clean surfaces by means of abrasive tools and that are characterized in that the metal surface to be cleaned, stripped and / or polished is washed with abrasives that can be applied to the head of the tool or dissolved. in porous elements. United States patent US-A4206028 combines with abrasive action or electrochemical stripping by means of a suitable agent located between the aforementioned head and the surface to be treated through which a direct current with a positive pole is passed, agent which is applied to the surface to be treated while applying the negative pole to the tool head mentioned above, or else ultrasound is used that is supplied by an emitter and a sonotrode that are separate from the tool or head mentioned above; if necessary, the head is used in combination with alternating current and / or with a liquid that applies electrolyte to the surface to be treated, thus taking advantage of the reversal of polarity.

Furthermore, a similar device of the prior art that has been known for many years has not found practical application due to the difficulty in using the instruments used and due to the impossibility of defining the working environment of the electrochemical agent or ultrasound. , even though the supply is in the aforementioned head or tool of the electrolytic liquid, which is attached but which is produced together with the abrasive material.

In addition, the prior art includes US-A-4772367, which comprises a head for cleaning the interior of pipes, in which a branched electrode is located near the external surface of the head to produce an electrochemical action by means of the electrolyte supplied within the head and surface mentioned above - a dielectric coating allows the electrolyte to remain in place near the surface: the dielectric coating is not in contact with the surface, but a cavity remains to allow the electrolyte to flow out through the tubing.

However, the above-mentioned head for pipes illustrates the disadvantages of the electrochemical cleaning technology specified in US-A-5964990 which is characterized therein in that the dielectric coating is also interrupted with materials that are highly resistant to heat, which makes it impossible to avoid wasting time due to the dielectric coating being worn out and the disadvantage remains that the electrolyte is removed from the surface to be treated as mentioned in all the above examples.

The prior art also shows patent application EP-A-0289168, which describes a device for electrical treatment, for example polishing, of a metal surface comprising a housing having a sealing contact with the surface with deformable sealing means, an electrolyte chamber in the housing and the electrolyte passing through the chamber to activate electrolytic action with electrical current on the surface.

From the prior art, patent application DE-A-3305967 is also known, which describes a device for keeping electrolytic acid in a chamber on the surface to be treated; a continuous means of sealing with a pair of lips that seal the edge of that chamber on the surface to be treated.

Finally, the prior art includes the manual method of chemical cleaning of metal surfaces with stripping agents in the form of a concentrated gel that are manually placed by the operator on the cleaning area and left for a period of time ranging from a few minutes to several hours for the reaction to take place and then washed away so that the entire agent is lost when washing through the drain point, So the workplace has to be equipped with sewage treatment systems to avoid contamination of the external environment.

This is of considerable scope for the improvement of the prior art by means of a device that cleans metal surfaces, which is highly effective and does not have the disadvantages of the prior art.

The above observations show that it is necessary to solve the technical problem of finding a type of electrolytic and / or ultrasonic cleaning machine that guarantees high pickling performance, ease of use, low consumption of pickling agent, low operating power, which The user can subject, whenever he wants, to high or low operation and effectively avoid the contamination of the workplace and the environment.

The invention solves the aforementioned technical problem by the machine defined in claim 1. Preferred embodiments of the machine are defined in claims 2 to 6. A localized cleaning machine comprising acid for pickling or a composition / mixture of chemical elements that act as a pickling acid that is applied manually or by mechanically applied instruments to the surface to be treated and characterized in that the acid is kept in a limited amount in the working position by a cell made of a material that supports the corrosive effect of the acid; this cell is of the same volume as the acid used, in other words by filling it completely with acid or reducing its volume to the volume of the acid in the perimeter of the cell that is projected onto the surface to be treated; and this acid is activated by the action of a device that activates the pickling action of the acid in its own right.

Preferably, at the edge of the aforementioned cell near the surface to be treated, a peripheral seal is provided for the edge against the aforementioned surface to be treated.

The activation device mentioned above consists of an electric current generator2

ES 2 284 536 T3 ca, one pole of which is connected to the surface material to be treated while the other pole is connected to an electrode of an electrically conducting material, located inside the cell and not in direct contact with the surface to be treated except only through its etching acid; This electric current generates in the cell the electrolytic action between the surface and the electrode mentioned above.

The activation device mentioned above consists of an ultrasound generator applied to a metallic sonotrode, one end of which is located inside the cell mentioned above; the action of ultrasound vigorously activates the pickling action of the acid.

The electrode also acts as a sonotrode, or vice versa; the pickling action within the cell is also subjected to both electrolytic and ultrasonic actions.

The electrode and / or sonotrode is / are manufactured movable within the cell in order to adapt the volume to the volume of acid contained in the cell.

The electrode is equipped with a toothed indentation in order to increase the surface of the electrode that comes into contact with the pickling acid, over the surface seen within the electrolytic cell mentioned above.

The electrode is equipped with an added plate that improves conductivity in combination with the etching acid on the surface seen within the above-mentioned electrolytic cell.

The electrode is equipped with a toothed indentation on an added plate that improves conductivity in combination with the pickling acid in order to increase the surface area of ​​the electrode that comes into contact with the pickling acid, at the surface seen within the electrolytic cell.

The seal at the edge of the cell in contact with the surface to be treated, which consists of a ring with a circular cross section that is housed in a ring-shaped seat around the edge.

The seal around the edge of the cell in contact with the surface to be treated consisting of a ring with at least one lip facing the surface and is housed in the ring-shaped seat around the edge.

The seal around the edge of the cell that comes into contact with the surface to be treated and consists of a ring-shaped suction cup that faces the surface to be treated that is connected by means of conduits and pipes to a system vacuum suction.

In the electrode and / or sonotrode mentioned above, there is at least one diaphragm valve for the release of the fumes generated during pickling; at the same time the cell also has holes to allow the fumes to escape.

Near the cell, a device to aspirate the fumes leaving the cell.

A series of ventilation holes connected to the system to aspirate and purify the aspirated polluting fumes.

An extractor hood, with a lower edge near the edge of the cell, connected to the system to aspirate and purify the aspirated polluting fumes.

A ring seal with a pair of flanges, the cavity between them being connected to the system to aspirate and purify the aspirated polluting fumes.

A separator between the pickling acid and the suction and scrubbing system mentioned above; the aspirated liquid or gelatinous part in the case of a gel is separated from the fumes in the above-mentioned separator before the fumes are purified.

A ring-shaped cell with sealing rings that are equal to the outer / inner diameter and that are close to the inner / outer diameter of the surface of the pipe / round bar to be treated; a supply and return line for the pickling acid to be supplied to the cell, along with an electrical cable connected to the electrode.

The aforementioned cell equipped with two series of radially arranged supply and return holes for the pickling acid; these holes are arranged radially and / or at angles to each other.

This invention provides the following advantages: the cleaning machine is much more efficient than prior art machines; a limited area of ​​the surface to be treated that overlooks the cell volume is cleaned; the energy required to activate acid pickling is much less than that required for manual operations or for electrolytic cleaning carried out in dip tanks; the scope of the cleaning machine is not limited by buffer replacement or other manual tasks such as dispensing and washing the pickling gel; Ultrasound can also be used with the pickling acid on the cell to clean surfaces that are not electrically conductive; the combined use of electrolytic cleaning power and mechanical ultrasonic cleaning power enables cleaning capacity to be greatly increased and thus enables cleaning costs to be greatly reduced.

Some purely illustrative embodiments of practice of the invention are shown as mere examples in the accompanying drawings: Figure 1 is a sectional drawing of an electrolytic cleaning cell according to the invention; Figure 2 is a sectional drawing of a mechanical ultrasonic cleaning cell, which is equipped with an extractor hood to suck in excess pickling acid and fumes; Figure 3 is a sectional drawing of an electrolytic cleaning cell, which is equipped with a ring-shaped suction cup that is fixed to the surface to be treated and with an extractor hood to aspirate the fumes; Figure 4 is a sectional drawing of a combined electrolytic and ultrasonic cleaning cell that is equipped with a single lip seal and an extractor hood to draw in excess fumes and electrolyte; Figure 5 is a drawing of the separator that separates the fumes from the electrolyte that is drawn downstream of a cleaning cell.

The following is shown: 1, Figure 1 is the cell of a rigid, dielectric heat resistant material, preferably highly resistant plastic, within which is located a metallic electrode 2 with peripheral sealing rings 3; 4 is a pipe inside the electrode of a material that is resistant to pickling acid and acts as an electrolyte: the lower edge of the cell that comes into contact with the surface 5 to be treated is equipped with a

ES 2 284 536 T3 sealing ring 6 to be defined, a volume 7 within which cleaning takes place; 8 is a metal plate with superior electrical conductivity, equipped with teeth 9 that penetrate the electrolyte in the zone 7 in order to increase the surface that is in contact with the electrode and the electrolyte. Figure 2 is a sonotrode to which an extractor hood 12 is applied, the lower edge 20 of which is close to the surface 5 to be treated: the fumes and excess pickling acid escaping from the seal 6 are sucked in by the sucked air In the cavity 21, the air is connected to the aspiration system via the conduit 22.

The following is also shown: 25, Figure 3 shows a cell with a ring-shaped suction cup 26 at its lower edge; 27 shows conduits within the cell that produce vacuum by means of a vacuum system that is not illustrated and to which the conduits are connected by conduits 28; 29 it is the electrode located in the cell that is equipped with diaphragm valves 30 to allow the fumes to pass through and the pickling acid to be retained in the volume 7 mentioned above; 31 shows vents in cell body 25; 33. Figure 4 is a sonotrode that also functions as an electrode, equipped near the inner surface of volume 7 of cell 1 with a metal plate 42 with higher electrical conductivity; 43 is a ring-shaped lower lip for sealing cell 1 to delimit volume 7.

Figure 5 is the pickling acid supply line and, where present, the electrode acting as an electrolyte; 55 is the pickling acid pump; 56 is a cleaning cell of the type noted above with a system for aspirating excess acid; A are the return air paths to transport the acid G to the conduit 57 connected to the separator 58, which is equipped with diaphragms 60 with staggered orifices 61; F is the air and fumes that the fan 62 separates and pushes towards an additional purification filter.

The spot cleaning machine is presented as follows. The cell is somehow filled with the pickling acid, which is also an excellent electrolyte due to its chemical properties, also by means of a brush if the acid is in the form of a gel, then the cell is put in contact with the surface 5 to be treated and cleaning begins. If there is only one electrode 2, as in Figure 1, a direct or alternating current is passed through the acid. As with the prior art, the different applied currents generate a high level of energy if the anode (+) is applied to the surface 5 and the cathode (-) is applied to the electrode, and vice versa, much less energy is obtained and this tends polishing the surface 5 to be treated; finally with alternating current the effect falls between the two mentioned above. If there is only one sonotrode, the acid is mechanically disturbed by the agitation produced by the ultrasound and the resulting etching is far superior to the mere deposition of the gel obtained by the prior art. Finally, after cleaning the point, the operator moves the cell and repeats the operations mentioned above.

The above-mentioned single cell cannot be used with liquid pickling acid so the acid must be supplied by a pump

55, which can be operated intermittently or continuously, from separator 58 or from a storage tank, if the small amount required can be lost. In addition, it is very useful to maintain this supply at high levels and collect excess pickling acid, also in gel form, together with the fumes generated by cleaning the surface, by means of the extractor hood 19 or suction in the cavity through the ring-shaped edges, that is, to replace the acid that becomes overheated during operations and emit the polluting fumes and carry with them the dirt removed from the surface. If the acid is not recirculated or cannot be recirculated completely, the suction of the fumes that have escaped from the cell through the ventilation holes located in the hollow discharge tube is not effective, however, also through the valves. diaphragm.

Simultaneous action on the electrolytic and ultrasonic cleaning cell greatly increases cleaning efficiency. As all the figures of construction forms show, except those showing the internal or external diameters of the pipes or round bars, the two effects of electrolytic and ultrasonic cleaning can be combined because they are applied to the pickling acid contained in volume 7 of the cell by the same organ with the double function of electrode and sonotrode.

Both electrolytic and ultrasound treatments of the acid are enhanced by the possibility of reducing the volume 7 of the cell 1, 25 to very low levels, making the electrode 2, 29 the sonotrode 18, 41 run through your body until the surface 5 to be treated, this movement is made possible by the presence of the sealing ring 3 between the cell and the electrode mentioned above; Another way to increase the electrolytic action is to point a metal plate 8, 42 with very high conductivity or that is polarized towards the surface to be treated of the electrode that points towards the volume 7 of the cell or alternatively or alternatively equip the end of the electrode with teeth 9 that increase the area of ​​the surface that is in contact with the pickling acid.

The ring-shaped suction cup 26 on the edge of the cell ensures safe positioning and a secure seal on the surface 5 to be treated: therefore, the cell must be equipped with diaphragm valves 30 to allow fumes to escape, whereas in the case of a ring seal 6 or a lip seal 43, excess pickling fumes and acid are normally escaped. Finally, the individual flanges 38 or flange 43, 66 allow the cell to move even during operation.

The body of the cells is made of a rigid dielectric material that is resistant to heat and preferably highly resistant plastic, while the material of the electrode and / or sonotrode is metal and can be coated with a layer that is resistant to the action of the acid of etching in the conduit and / or coated by the highly conductive plate 8.42 mentioned above on the surface facing the cell volume 1.25.

In the practical embodiment, the details may be different from those indicated, but be technically equivalent and still fall within the scope of this invention as defined in the claims.

ES 2 284 536 T3

Therefore, the cell can be made of non-insulating material but have an insulating coating.

Finally, much less economically, the cell material may not be resistant to corrosion due to etching acid: the cell will have a much shorter life than cells of a material that is resistant to acid corrosion; or the cell can be protected by a layer of a material that is resistant to acid corrosion, as described above for a non-insulating material.