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  • 专利说明
  • 权利要求
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    • 专利摘要:
    Method for dry treating metallic surfaces (1) by means of electrically active solid particles (9) comprising a stage of contact of the particles (9) with the electrode (3) of an electric source (2), a stage of projection of the particles (9) towards the metallic surface to be treated, and a stage of transmission of electrical charge from the particles to the metallic surface to be treated. The transmission of electricity between the electrical source (2) and the metal surface (1) during the projection stage is preferably by net charge of the particles (9), or by electrical conductivity by contact or by electrical conductivity through arcs. The current applied to the electrode is preferably a direct current or a current containing positive sections and negative sections. Preferably in the middle between the particles (9) there is a conductive element that increases the conductivity between the particles by means of voltaic arcs. Preferably, the method comprises a step of using abrasive particles simultaneously or consecutively with the electrically active particles. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2818473A1
    申请号:ES201930716
    申请日:2019-08-01
    公开日:2021-04-13
    发明作者:Hernandez Marc Soto；Gimpera Marc Sarsanedas
    申请人:Drylyte SL；
    IPC主号:
    专利说明:

    [0002] METHOD FOR DRY TREATING METAL SURFACES USING SOLID ELECTRICALLY ACTIVE PARTICLES
    [0004] OBJECT OF THE INVENTION
    [0006] The object of the invention is a method for treating or polishing metallic surfaces characterized by the projection of electrically active solid particles on the piece to be polished from an electrode connected to an electrical source. This method allows dry polishing of metal surfaces without having to introduce the surface to be treated in a tank, which allows treating surfaces that due to their size, location, etc. characteristics. previously they could not be treated, such as large elements, immovable elements, etc. This method has advantages and characteristics that represent a remarkable novelty with respect to the current state of the art.
    [0008] FIELD OF APPLICATION OF THE INVENTION
    [0010] The field of the present invention is the industrial sector dedicated to the treatment of metal surfaces. Especially the industrial sector dedicated to the polishing of metal surfaces, with applications in fields such as, for example, aeronautics, construction, automotive, medicine, laser sintering, among many other fields of application.
    [0012] BACKGROUND OF THE INVENTION
    [0014] Polishing systems are currently on the market by projecting abrasive particles onto the surface to be treated. The particles are forcibly propelled to the surface, producing a polishing effect proportional to the impact force. Polishing systems by spraying abrasive particles have a number of drawbacks. Polishing systems by projection of abrasive particles cause an inhomogeneity in the applied surface since the abrasion is related to the pressure between the surface and the particles. The most exposed parts suffer more abrasive action, which generates a loss of definition of vertices and edges. This limits its application in cases that require precision or to maintain the edge. Likewise, polishing systems by projection of abrasive particles cause inclusions of the same abrasive particles on the metal surface, reducing the properties of the surface in terms of durability, chemical resistance and traction. Also noteworthy are the risks to respiratory health of these polishing systems by projection of abrasive particles that use abrasive particles, both due to abrasive particles, as well as dust and suspended microparticles generated during the process.
    [0016] On the other hand, there are the dry electropolishing systems described in ES2604830 (A1) as a "method for smoothing and polishing metals through the transport of ions by means of free solid bodies". This method is based on introducing and rubbing the part to be treated in a medium composed of solid particles capable of ionic transport while an electric potential is applied between the part and a counter electrode. This dry electropolishing system allows to obtain surfaces with a low roughness and specular finishes. Furthermore, this system does not substantially modify the vertices or edges of the object to be polished. Dry electropolishing systems have several drawbacks, among which are; the fact that it is impractical when it comes to polishing large parts, such as the wing of an airplane, and the fact that it is not possible to apply it to treat immovable elements, such as construction elements, among others.
    [0017] The method of dry polishing metal surfaces by projection of electrically active particles that is the object of the invention represents a notable advance since it allows combining the specular finishes of the dry electropolishing system with the advantages of the polishing system by means of projection of abrasive particles. expanding the field of application of the first and reducing the inconveniences of the second. However, in order to reach this objective, it is necessary to overcome in a non-obvious way several obstacles present, such as the nature of the solid particles to be used, their compaction or the type of electric current.
    [0019] EXPLANATION OF THE INVENTION
    [0021] The method of dry polishing metal surfaces by projection of electrically active particles has a series of advantages and identifying characteristics that are detailed below.
    [0023] The term "solid electrically active particles" refers in this text to particles that can be electrically charged, that can conduct electricity, or both simultaneously characteristic to some extent.
    [0025] The term projection of particles is understood in this text in the broad sense of any method or system by which the particles reach the surface to be treated, regardless of whether the driving force has been gravity, the flow of a fluid, compressed gas , electrostatic forces or centrifugal force among others.
    [0027] The term electrical source is understood in this text as any element capable of delivering electrical energy to electrically active solid particles. The electrical source provides electrical energy to the solid particles. The electrical current applied by the source Electric can be alternating, continuous or pulsed. Preferably, the electrical source includes a system that allows the applied voltage and intensity to be controlled.
    [0029] The essential stages that define the method object of the invention are:
    [0031] - Contact of an electrode of the electrical source with electrically active solid particles.
    [0032] - Projection of electrically active solid particles from the device onto the metal surface
    [0033] - Contact of electrically active solid particles with the metal surface
    [0035] The minimum elements that define the device object of the invention are:
    [0037] - A set of electrically active solid particles
    [0038] - An electrical source with an electrode that transmits electrical charge to electrically active solid particles
    [0039] - Projection means of electrically active solid particles on the metal surface to be treated.
    [0040] - A nozzle through which electrically active solid particles exit the device.
    [0042] The interactions that occur between these minimal elements are as follows. The electrically active particles contact an electrode of the electrical source and this transmits electrical charge to them. From the electrode, the particles move towards the metal surface to be treated, where they contact and transmit part of the electrical energy. This contact generates redox processes on the metal surface producing a polishing effect. Figure 1 shows the design of a prototype as an example.
    [0043] Due to the electrical nature of the process, the surface to be treated must be conductive, preferably metallic. This includes surfaces of non-conductive materials, such as plastics that have undergone a metallization process.
    [0045] The transmission of the electric charge from an electrode to the surface to be treated by means of a particle flow is not described in the literature according to our knowledge to date. Three possible electrical charge transmission mechanisms have been conceptualized, producing these and a variety of intermediate or derived situations simultaneously:
    [0047] 1) by net charge of the particles,
    [0048] 2) by contact electrical conductivity, and
    [0049] 3) by electrical conductivity through voltaic arcs.
    [0051] A schematic representation of these mechanisms can be seen in Figure 2.
    [0053] Depending on controllable parameters of the system, one mechanism can be promoted over the others. Mainly, these parameters are electrical, the type of particles, the type of projection and the surrounding medium.
    [0055] The mechanism of transmission of electric charge by particles with net charge is favored in low compaction conditions. In the ideal case the particles are isolated from each other, that is, without direct contact between them. The energy density that the particles can carry, U, can be calculated from the dielectric constant of the particles £ r and the applied electric field E.
    [0058] U = 2 £ ° £ rE
    [0059] For example, it has been experimentally proven that particles of macroporous polystyrene-divinylbenzene sulfonated gel containing 4% sulfuric acid, with a diameter of 600 pm, present an £ r = 1.10-108 (measured at 100 Hz) which for an applied electric field 30 kV implies a stored energy density of 437 kJ m-1. These same particles when projected onto a metal surface produce an electrical discharge that performs work on the surface. For example, when projected onto a 316 stainless steel surface they produce a detectable current flow and an appreciable surface modification.
    [0061] This mechanism is favored by particles with a high dielectric constant and high applied voltages that allow a higher density of stored electrical energy, and a high separation of the particles that prevents them from discharging each other.
    [0063] The mechanism of transmission of electrical charge by electrical conductivity by contact is favored in conditions in which a continuous contact of particles is established from the electrical source to the surface to be treated. In this case, an electric current is established directly through the particles, so this mechanism is favored by particles with high electrical conductivity and high flow compaction. This mechanism produces comparatively high current intensities, which allows the workpiece to be processed at a higher speed.
    [0065] The electrical charge transmission mechanism by discharges and arcs involves the transmission of electrical charge from the electrical source to the part through the particles and the interparticle medium. That is, the transmission of electric charge takes place, at least partially, at through ionized gas. There is a range of possibilities including avalanche discharge and corona discharge.
    [0067] Although these discharges can occur electrode-particle and particle-surface, they mainly occur between particles. This implies that the medium between particles and the distance between particles are a parameter of great influence to trigger this mechanism.
    [0069] For each type and size of particle there is a range of distances between particles in which this mechanism is triggered. Increasing the conductivity of the interparticle space increases the range of functional distances and allows greater room for maneuver. In a preferred embodiment, an element is added that promotes conductivity between the particles by means of voltaic arcs. These elements can be solid, liquid, ions, etc., as well as the use of electromagnetic radiation.
    [0071] In the case of liquid elements that favor conductivity between the particles by means of voltaic arcs, those that have the capacity to generate microdroplets or aerosols that increase the conductivity of the medium between particles stand out. There are also solid elements that favor conductivity between the particles through voltaic arcs that, due to electrical transmission, generate micro- or nano-particles in suspension, such as, for example, derivatives of carbon such as carbon fibers, graphite, or micronized carbon. Due to the passage of electricity, these carbon compounds raise their temperature and generate volatiles or suspended elements that favor electrical transmission. It is also possible to add elements that favor conductivity between the particles by means of electric arcs with the ability to retain electrolytic liquid, such as gel-type materials, with some notably larger dimensions. to the average diameter of the particles, such as bars or cylinders, to make electrical bridges.
    [0073] The generation of ions in the interparticle space considerably increases the conductivity between the particles through arcs. Ions can be generated by ionizing and volatile substances, such as iodine, or by using electromagnetic, ionizing or non-ionizing radiation. These different elements that increase the conductivity of the particle spacing can be used in combination with each other. They can be used in admixture with the electrically active particles, added elsewhere to condition the medium, or they can be incorporated into the electrically active particles. Preferably, the particles can retain a certain amount of liquid, in that case the vibrations and frictions of the process generate microdroplets and aerosols between the particles, which modifies the conductivity of the system. It is also possible to use ultrasound to generate microdroplets, or nebulizer systems. The use of electromagnetic radiation can increase the conductivity of the medium. The use of ionizing electromagnetic radiation is ultraviolet rays and X - rays and directly generates ions in the medium to increase the conductivity of the particles and gas assembly therebetween. The use of non-ionizing electromagnetic radiation to increase conductivity is also possible. For example, by using microwave radiation it is possible to generate plasmas from particles that increase the conductivity of the medium.
    [0075] Electric shocks occur more easily with alternating current than with direct current. For example, experimentally visible arcs are seen using direct current from 25 kV. Under identical conditions using alternating current at 50 Hz, arcs are observed at a voltage an order of magnitude lower, of 2 kV.
    [0076] To maintain a stable current flow with corona arcs, you can increase the frequency of the alternating current, even several orders of magnitude, work with voltages of the order of kilovolts, as well as reduce the pressure of the medium.
    [0078] The electrical source provides electrical energy to the solid particles. The electrical current applied by the electrical source can be alternating, continuous or pulsed. Preferably, the electrical source includes a system that allows the applied voltage and intensity to be controlled. Direct current is the one that produces the fastest effects on the surface, so in particle / surface systems that do not accumulate residues during the process, it is the preferred option. If the system with direct current produces superficial accumulations, it is possible to improve the results by using current that contains polarity reversals. The most affordable way to obtain current with reversals of polarity is to use alternating current. This can be used directly or rectified by diodes or other electroactive elements. A preferred alternative is the use of a pulsed current electrical source that allows control of the applied pulse parameters, such as positive and negative voltages, duration of positive and negative pulses, duration of pauses, etc.
    [0080] The electrical parameters applied by the electrical source determine the effects of the particles on the surface. The applied potential difference to produce polishing effects is in a wide range from 1 V to 50 kV and is an aspect that determines the electrical transmission mechanism. The current applied to the electrode can be direct, alternating or pulsed. For example, a 30 kV direct current source, with a pulsed and non-compact projection of particles by gravity, at a distance of 18 cm between the electrode and the surface to be treated, produces polishing effects on the metal surface.
    [0081] As for example also, a source of direct current at 30 V, with a compact and continuous projection of particles by gravity, at a distance of 2 cm between electrode and surface to be treated produces polishing effects on the metallic surface. As for example also, a source of alternating current of 50 Hz at 2 kV, with a pulsed and non-compact projection of particles by gravity and driven by air at 5 bar, at a distance of 18 cm between electrode and surface to be treated produces arcs Visible electrical and polishing effects on the metal surface. It is possible to qualitatively attribute to each of these examples a higher relative proportion of each of the electric charge transmission mechanisms previously explained.
    [0083] The electrode is a conductive element electrically connected to the electrical source with which the particles contact before being projected onto the surface to be treated. The shape of the output electrode depends on the application or surface to be treated. In general, the aim is to maximize the contact area of the particles with the electrode in the moments prior to projection. For example, a tube through which the particles circulate is connected to a metallic exit electrode, for example made of copper, in the shape of a narrowing cylinder. As for example also, to treat plates or relatively flat surfaces, the exit electrode can be a "curtain" system for applying the particles, that is, a linear exit slot. In a preferred embodiment the electrode consists of the nozzle.
    [0085] Solid electrically active particles can transmit electrical charge from the electrical source to the metal surface to be treated. Preferably, the solid particles can retain liquid. This retained liquid can partially dissolve the oxides and salts formed due to the passage of electric current, which improves the cleaning of the surface. Preferably, the electrically active solid particles are made of a polymer gel, as it offers a compromise between physical integrity and the ability to retain liquid in its structure. Preferably, the electrically active particles are made of sulfonated polystyrene-divinylbenzene gel because they favor the process due to their reversible ability to retain dissolved metal ions. Preferably, the liquid retained in the electrically active particles is an acidic aqueous solution since most metal oxides, hydroxides and salts are more soluble in an acid medium. Preferably, the acidic aqueous solution includes one or more strong acids ( pK a <2) due to their greater dissociation increase electrical transmission while improving the solubility of metal oxides, hydroxides and salts, resulting in greater surface cleaning .
    [0087] The electric charge transmission process can generate a redox reaction on the metal surface, which can lead to the formation of metal oxides on the surface. Controlled removal of the oxides formed is crucial for a good surface finish. These surface oxides can be removed, for example, by abrasive action or by dissolving action.
    [0089] The removal of metal oxides on the surface by an abrasive action can occur by the action of the same electrically active particles that act as abrasive particles. Oxides can also be removed by the action of non-electrically active abrasive particles. The action of the abrasive particles can be carried out simultaneously (abrasive particles and non-abrasive particles are projected at the same time) or consecutively to the action of the electrically active particles. With this configuration, it would be a novel dry electropolishing process combined with an abrasive sandblasting process.
    [0090] Alternatively or in addition, the removal of the surface oxides can be carried out by means of a dissolving action. The dissolving action can be carried out by a free liquid or by liquid retained in the particles. Preferably the dissolving action is carried out by liquid retained in the electrically active particles to produce the dissolution of the oxides in the same stage as their formation.
    [0092] The projection of particles on the metal surface requires an impulse force. In the simplest version, this impulse is the force of gravity.
    [0094] Preferably, this impulse is delivered by a controllable element. This controllable element is preferably the impulse of a compressed gas. The use of a pressurized gas allows to control the speed and the particle-surface contact pressure, as well as to have control over the flow and compaction of the particles.
    [0096] In an alternative embodiment, the particles are projected onto the metal surface by the impulse of a turbine that propels the particles by centrifugal force.
    [0098] In an alternative embodiment, the particles are projected onto the metal surface discontinuously by the impulse of a connecting rod-crank system. This allows a projection of the particles in a discontinuous manner with a highly configurable system in terms of speed and volume of each projection.
    [0100] In an alternative embodiment, the particles are projected onto the metal surface continuously by the impulse of an endless screw system. This allows you to create a continuous flow and compact of particles, favoring the mechanism of electrical transmission by contact.
    [0102] The outflow of the particles through the nozzle can be controlled by valves and timers to make it continuous or pulsed.
    [0104] The shape of the projection of the particles on the surface can be adapted to the needs of the part to be treated. For example, if you want to process a flat surface within a manufacturing chain, you can use a nozzle that allows the projection of particles in the form of a curtain on the surface that allows you to cover the entire width of the surface of the moving part. under the curtain.
    [0106] In an alternative embodiment, the projection can be carried out using a nozzle in the form of an application hose through which the propelled particles would exit. These application hoses can be configurable for example in terms of direction or size of the outlet hole. These hoses can be moved in an automated way, for example inside a projection booth, or they can be used manually against the surface to be treated. In the event that the projection of the particles is produced by compressed gas, these hoses can incorporate in their final section an air dissipative element at the point of delivery of the particles to compact the particles and maintain a high conductivity.
    [0108] The surface to be treated can be insulated, be connected to an earth connection or to an electrical source. Preferably the surface to be treated is connected to an electrode of the electrical source. In this way, a greater control of the applied potential difference is obtained and it is possible to measure the flow current between the exit electrode of the particles and the surface to be treated.
    [0109] The surface to be treated must be conductive. Preferably the surface to be treated is metallic. This includes parts made of plastic materials with a surface that has been metallized. Metals and alloys that can be treated include, but are not limited to, all types of irons and steels, chrome-cobalt alloys, nickel and nickel alloys, such as nitinol, zinc and zinc alloys, such as Zamak, aluminum and alloys, titanium and alloys, copper and alloys, tungsten carbide, etc.
    [0111] The versatility of this system makes it possible to treat large flat surfaces, large pieces, surfaces that are immovable, such as construction structures, etc.
    [0113] The electrical parameters applied by the electrical source determine the effects of the particles on the surface. The applied potential difference to produce polishing effects is in a wide range from 1 V to 50 kV and is an aspect that determines the electrical transmission mechanism. The current applied to the electrode can be direct, alternating or pulsed. For example, a 30 kV direct current source, with a pulsed and non-compact projection of particles by gravity, at a distance of 18 cm between the electrode and the surface to be treated, produces polishing effects on the metal surface. As for example also, a source of direct current at 30 V, with a compact and continuous projection of particles by gravity, at a distance of 2 cm between electrode and surface to be treated produces polishing effects on the metallic surface. As for example also, a source of alternating current of 50 Hz at 2 kV, with a pulsed and non-compact projection of particles by gravity and driven by air at 5 bar, at a distance of 18 cm between electrode and surface to be treated produces arcs Visible electrical and polishing effects on the metal surface. It is possible to qualitatively attribute to each of these examples a higher relative proportion of each of the electric charge transmission mechanisms previously explained.
    [0114] Other elements that improve the operation of the invention are:
    [0116] - A previous deposit for the delivery of particles.
    [0117] - A collector for collecting the particles. The collector and the pre-tank can be the same element.
    [0118] - A system of recirculation of particles from the collector to the delivery tank, in case they are not the same element.
    [0119] - Vibrators at the points of storage or circulation of the particles to facilitate their transport, as well as transmitting vibration to the surface to be treated.
    [0121] Preferably, the device comprises a deposit for the delivery of solid particles prior to electrical contact and projection. This deposit ensures the delivery of particles to the system in a constant way and avoids downtime.
    [0123] Preferably, the device comprises a collector for collecting solid particles once they have impacted against the surface to be treated. This collector is designed for each specific embodiment and can adopt various conformations, as can be seen in the examples. This element prevents the dispersion of particles everywhere and at the same time allows the recirculation of particles.
    [0125] In the embodiments that allow it, preferably the delivery tank and the collection manifold are the same element. This allows to simplify the design of the device and avoid redundancy of elements, which results in lower costs while maintaining the same functionality.
    [0126] In case the delivery tank and the collection manifold are not the same element, there may be a particle recirculation system between the collection manifold and the solid particle delivery tank. This system allows the reuse of particles automatically, thus avoiding the necessary human effort and improving the degree of automation.
    [0128] The device preferably comprises a vibrator or vibrators that vibrate the particles to facilitate their movement. Said vibrator can preferably be located in the delivery tank and / or in the collection manifold. The movement of a granular material such as the particles used in this process can form arcing blockages. The use of vibrators in the tanks and circulation tubes notably reduces the formation of arches, which avoids blockages at the circulation points.
    [0130] Consequently, the following steps are identified that improve the method object of the invention are:
    [0132] - Recirculation of particles from the collection collector to the delivery tank, if they are not the same element.
    [0133] - Vibration of electrically active solid particles
    [0135] This novel technology is conceived with a wide possible variety of end applications. By way of example and without limitation purposes, some of the possible applications are presented. One application is in individual polishing units to treat large structural parts, such as an airplane wing to improve its aerodynamics. A final application is its use in continuous in-line processes to treat metal surfaces after production or as a previous step to other treatments.
    [0136] Another end application is in self-contained portable polishing devices.
    [0137] DESCRIPTION OF THE DRAWINGS
    [0139] Figure 1. Exemplary design of the device that executes the polishing method object of the invention.
    [0140] Figure 2A. Diagrams of the mechanism of electricity transmission between the electrical source and the metal surface by means of the net charge of the particles.
    [0141] Figure 2B. Diagrams of the mechanism of electricity transmission between the electrical source and the metallic surface by means of electrical conductivity by contact.
    [0142] Figure 3C. Diagrams of the mechanism of transmission of electricity between the electrical source and the metal surface by electrical conductivity through voltaic arcs.
    [0143] Figure 3. Schematic of a device for in-line surface treatment
    [0144] Figure 4. Scheme of a portable device for surface treatment
    [0145] Figure 5. Scheme of a device with a booth for surface treatment
    [0146] PREFERRED EMBODIMENTS OF THE INVENTION
    [0148] Below are several exemplary cases without any purpose of limitation.
    [0150] Embodiment 1
    [0152] The device consists of a delivery tank (7) of particles (9) whose outlet is connected to a copper tube that acts as an electrode (3), in turn connected to an electrical source (2). The particles (9) fall continuously by gravity to the surface to be treated (1), which is connected to the electrical source (2) through the counter-electrode. The Particles (9) fall, after contact with the piece, to a collection collector (6) for subsequent recirculation by means of a recirculation system (5). Both the particle delivery tank (7) and the collection collector (6) have a vibrator (8). A schematic representation is found in Figure 1.
    [0154] In an exemplary case, the particles (9) used are macroporous polystyrene-divinylbenzene sulfonated gel particles charged with an electrolyte solution containing 4% sulfuric acid. This prototype has been tested with different types of electrical current: direct from 1 to 60 V; AC 50 Hz to 50,000 Hz 0 to 220 V.
    [0156] With these parameters, the polishing method has been tested for treating a 316 steel surface with different types of electrical current: continuous up to 35 kV, alternating at 50 Hz up to 15 kV.
    [0158] The direct current results show a linear behavior of the intensity with respect to the potential difference. It is observed that after a treatment of 5 effective minutes at 30 kV there is a reduction of R a from 0.37 to 0.34 gm in the area most exposed to the flow of particles.
    [0160] The results using alternating current at 50 Hz show a linear behavior in the range of 0 to 5 kV. Increasing the voltage from this point does not produce a proportional increase in intensity. This effect clearly indicates a change of mechanism in the transmission of electric charge.
    [0162] Device for in-line surface treatment
    [0164] It consists of a device for in-line surface treatment. A schematic representation is found in Figure 3. In this For example, without limitation, it is designed to treat sheet metal. The device includes an electrical source (3), a "curtain" system for applying the particles (9), a conveyor system for the plate to be treated and a recirculation system (5) that collects the particles and deposits them in the delivery depot (7).
    [0166] The metal plate to be treated is located on a conveyor belt provided with vibration and connected to the electrical source. At one point along the conveyor belt there is a curtain-type particle projector (9). The linear applicator produces a linear projection of particles (9) on the surface to be treated (1) that covers the entire width of the plate to be treated. The plate moves through the particle curtain at a suitable speed that provides the treatment time to obtain the desired finishes. The curtain type particle projector includes a vibrator (8) to facilitate the flow of the particles. In the exit slot of the particles there is a metallic element, connected to the negative pole of the power supply that acts as an electrode (3). The particles contact this electrode (3) before reaching the surface to be treated (1). Near the point of contact, a recirculation system (5) is applied that sucks the particles after having contacted the surface and deposits them in the delivery tank (7).
    [0168] Portable device for surface treatment
    [0170] It consists of a portable device for surface treatment (1). A schematic representation is found in Figure 4. This device facilitates its joint transport, such as, for example, with wheels. The device includes a compressor and a compressed air tank, an electrical source (2), a particle delivery tank (7) and a recirculation system (5).
    [0171] The device can be connected to a power socket, alternatively it can include a sufficient electrical accumulator to provide the energy. The particle delivery tank (7) (9) in its lower part has an outlet towards the particle delivery hose, the tank can be provided with a vibrator (8) to facilitate the flow of particles (9). The particles (9) are propelled through the application hose by compressed air bar coming from the compressor. The required pressure depends on the length and placement of the application hose, a pressure between 3 and 10 bar provides good results. The application hose ends in a diffuser that allows part of the air to escape, forcing the compaction of the particles (9). The exit of the particles occurs through, or in contact with, an electrode (3), which can be an element of, for example, copper, 316 stainless steel or iridized titanium, connected to the electrical source (2) , preferably to the positive pole, preferably with an ammeter to monitor the intensity. The application electrode (3) is located at a distance of between 0.5 and 10 cm from the surface, in such a way that between the electrode and the surface there is a flow of particles to produce a current flow. The final part of the particle outlet is included in a collection collector (6) that is very close to or in contact with the surface to be treated (1). This particle collection collector (6) is connected to a recirculation system (5) comprising a second hose provided with suction, which collects the particles from the collection collector (6) after contacting the surface and directs them from back to the delivery tank (7) particles. The surface to be treated (1) is connected to the electrical source (1) by, for example, an electrical clamp, preferably to the positive pole. To polish surfaces not accessible by an operator or to improve precision, the system may include the use of a robotic arm.
    [0172] The design of the system is thought to occupy a compact volume and contains elements, such as wheels or sliding elements, that make it transportable.
    [0174] The applied current depends on the composition of the surface to be treated and the particles (9) used. For example, to treat a surface of 316 steel, good results are obtained using sulfonated polystyrene-divinylbenzene particles containing 4% sulfuric acid with a direct current of 12 V.
    [0176] Device for treating surfaces in the cabin
    [0178] It consists of a device for treating surfaces (1) in a closed booth (4). A schematic representation is found in Figure 5. The device includes an electrical source (2), one or more electrically active particle outputs (9) with electrodes (3), a system for anchoring the pieces to be polished, a cabinet (4) closed for treatment and a recirculation system (5) that sucks the particles from the collection collector (6), which in this example also acts as a delivery tank (7), towards the particle outlets.
    [0180] The metal pieces to be polished are placed on racks inside the cabin by means of suitable anchors, so that they are connected to the electrical source (2). The cabin (4) is provided with several particle outlets connected in its final section to electrodes (3). The projection of the particles (9) is produced by using compressed air, preferably in a range of 2 to 10 bar, preferably between 4 and 6 bar.
    [0182] The bottom of the cabin (4), which acts as a collection collector (6) and at the same time acts as a delivery tank (7), has an inclination and the Particles (9) are collected by a recirculation system (5) that transports them to the particle outlets.
    [0184] The electrical current applied depends on several factors such as the type of material, the total area to be processed, the distance between the particle exit point and the surface. For example, to polish 316 steel at a distance of 4 cm a total area of 25 cm2.
    权利要求:
    Claims (10)
    [1]
    1. Method for dry treating metallic surfaces (1) by electrically active solid particles (9) characterized in that it comprises the following steps:
    - Contact of the particles (9) with the electrode (3) of an electrical source (2)
    - Projection of the particles (9) towards the metallic surface to be treated
    - Transmission of electrical charge from the particles to the metal surface to be treated
    [2]
    2. Method for dry treating metallic surfaces (1) using electrically active solid particles (9) according to claim 1 characterized in that the transmission of electricity between the electrical source (2) and the metallic surface (1) during the projection stage is by net charge of the particles (9).
    [3]
    3. Method for dry treating metallic surfaces (1) by electrically active solid particles (9) according to claim 1 characterized in that the transmission of electricity between the electrical source (2) and the metallic surface (1) during the projection stage it is by electrical conductivity by contact.
    [4]
    4. Method for dry treating metallic surfaces (1) by electrically active solid particles (9) according to claim 1 characterized in that the transmission of electricity between the electrical source (2) and the metallic surface (1) during the projection stage It is by electrical conductivity through voltaic arcs.
    [5]
    Method for dry treating metallic surfaces (1) by electrically active solid particles (9) according to any of the preceding claims, characterized in that the current applied to the electrode is a direct current.
    [6]
    6. Method for dry treating metallic surfaces (1) by electrically active solid particles (9) according to any of claims 1-4, characterized in that the current applied to the electrode (3) is a current containing positive sections and negative sections.
    [7]
    7. Method for dry treating metallic surfaces (1) by electrically active solid particles (9) according to claim 4, characterized in that in the middle between the particles (9) there is a conductive element that increases the conductivity between the particles by means of electric arcs.
    [8]
    8. Method for dry treating metallic surfaces (1) using electrically active solid particles (9) according to claim 7 characterized in that the element that promotes conductivity between the particles (9) by means of electric arcs is a derivative of carbon, iodine, talc , cylinders and / or gel sticks.
    [9]
    9. Method for dry treating metallic surfaces (1) using electrically active solid particles (9) according to claim 7 characterized in that the element that promotes conductivity between the particles (9) by means of electric arcs is a source of ionizing radiation (ultraviolet, x-rays and y-rays), a non-ionizing radiation source (microwave), a nebulizer and aerosol generator, and / or an ultrasound source.
    [10]
    10. Method for dry treating metallic surfaces (1) using electrically active solid particles (9) according to any of the preceding claims, characterized in that it comprises a step of using abrasive particles simultaneously or consecutively to the electrically active particles.
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    同族专利:
    公开号 | 公开日
    ES2818473B2|2021-10-20|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JPH0259216A|1988-08-25|1990-02-28|C Uyemura & Co Ltd|Polishing method|
    US6156187A|1998-06-05|2000-12-05|Nissin Unyu Kogyo Co., Ltd.|Electrolytic integrated polishing method for external surface of metallic tubes and photosensitive drum substrate prepared thereby|
    US20140076739A1|2012-09-14|2014-03-20|Abbott Cardiovascular Systems, Inc.|Electropolishing device and method|
    WO2018172586A1|2017-03-20|2018-09-27|Steros Gpa Innovative, S.L.|Electropolishing device|
    法律状态:
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    ES201930716A|ES2818473B2|2019-08-01|2019-08-01|METHOD FOR DRY TREATING METAL SURFACES USING SOLID ELECTRICALLY ACTIVE PARTICLES|ES201930716A| ES2818473B2|2019-08-01|2019-08-01|METHOD FOR DRY TREATING METAL SURFACES USING SOLID ELECTRICALLY ACTIVE PARTICLES|
    PCT/ES2020/070499| WO2021019121A1|2019-08-01|2020-07-31|Method and device for dry treatment of metal surfaces by means of electrically active solid particles|
    IL290005A| IL290005D0|2019-08-01|2022-01-20|Method and device for dry treatment of metal surfaces by means of electrically active solid particles|
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