METHOD AND DEVICE FOR DRY TREATMENT OF METAL SURFACES BY MEANS OF ELECTRICALLY ACTIVE SOLID PARTICLES

Abstract

Methods and devices for treatment of metal surfaces by means of electrically active solid particles that include a step of contact of the solid particles with the electrode of an electric source, a step of shooting the particles towards the metal surface to be treated and a step of transmission of electric charge of the particles on the metal surface to be treated. The transmission of the electricity between the electric source and the metal surface during the step of shooting preferably is by net charge of the particles or by electric conductivity by contact or by electric conductivity by means of voltaic arches. The current applied to the electrode is preferably a DC or a current that contains positive sections and negative sections.

Claims

1. A method for treatment of a metal surface, the method comprising: placing a plurality of electrically active solid particles in contact with an electrode of an electric source and thereafter shooting the plurality of electrically active solid particles towards the metal surface so that the plurality of electrically active solid particles contact and transmit to the metal surface electricity.

2. The method for treatment of a metal surface according to claim 1, wherein the transmission of electricity between the electric source and the metal surface during the shooting of the plurality of electrically active solid particles is by net charge of the plurality of electrically active solid particles.

3. The method for treatment of a metal surface according to claim 1, wherein the shooting of the plurality of electrically active solid particles includes creating a chain of electrically active solid particles that extends between the electrode and the metal surface.

4. The method for treatment of a metal surface according to claim 3, wherein the solid particles in the chain of electrically conductive solid particles are in electrically conductive contact with adjacent solid particles.

5. The method for treatment of a metal surface according to claim 3, wherein the solid particles in the chain of electrically conductive solid particles are electrically connected with adjacent solid particles by means of voltaic arches.

6. The method for treatment of a metal surface according to claim 1, wherein a direct current (DC) is applied to the electrode.

7. The method for treatment of a metal surface according to claim 1, wherein a current is applied to the electrode, the current containing positive sections and negative sections.

8. The method for treatment of a metal surface according to claim 5, further comprising a medium positioned between the adjacent solid particles that promotes the formation of the voltaic arches.

9. The method for treatment of a metal surface according to claim 8, wherein the medium is selected from the group consisting of a carbon, iodine, and talc. U. The method for treatment of a metal surface according to claim 5, wherein the formation of the voltaic arches is promoted by means of a source of ionizing radiation, a non-ionizing source of radiation, a nebulizer and generator of aerosol and/or an ultrasounds source.

11. The method for treatment of a metal surface according to claim 1, further comprising treating this metal surface with abrasive particles, simultaneously or consecutively to shooting the plurality of electrically active solid particles towards the metal surface.

12. The method for treatment of a metal surface according to claim 1, wherein the plurality of electrically active solid particle comprise microporous gel particles of sulfonated polystyrene-divinylbenzene.

13. The method for treatment of a metal surface according to claim 1, wherein the microporous gel particles of sulfonated polystyrene-divinyibenzene contain sulfuric acid.

14. A system for treatment of a metal surface, the system comprising: a plurality of electrically active solid particles; an electric source with an electrode that is configured to transmit an electric charge to the plurality of electrically active solid particles; and means for shooting the plurality of electrically active solid particles on the metal surface after the electrode has transmitted the electric charge to the plurality of electrically active solid particles.

15. The system for treatment of a metal surface according to claim 14, wherein the electric source has a positive pole and a negative pole, the electrode being coupled to the negative pole and the metal surface being coupled to the positive pole.

16. The system for treatment of a metal surface according to claim 14, wherein the electrically active solid particles are propelled towards the metal surface only by the force of gravity.

17. The system for treatment of a metal surface according to claim 14, further comprising a centrifugal system that is configured to propel the electrically active solid particles towards the metal surface.

18. The system for treatment of a metal surface according to claim 14, further comprising a source of compressed gas that is configured to propel the electrically active solid particles towards the metal surface.

19. The system for treatment of a metal surface according to claim 14, further comprising a rod and crank system or an endless screw system that is configured to propel the electrically active solid particles towards the metal surface.

20. The system for treatment of a metal surface according to claim 14, further comprising means fur moving the metal surface during the treatment.

21. The system for treatment of a metal surface according to claim 14, further comprising a delivery deposit for storing the plurality of electrical active solid particles at a location apart from the electrode.

22. The system for treatment of a metal surface according to claim 21, further comprising a collector in which the plurality of electrically active solid particles are collected after having been shot against the metal surface.

23. The system for treatment of a metal surface according to claim 22, either comprising a recirculation system that is configured to transport the plurality of electrically active solid particles from the collector to the delivery deposit.

24. The system for treatment of a metal surface according to claim .21 further comprising a vibrator physically coupled to the deliver deposit.

25. The system for treatment of a metal surface according to claim 22, further comprising a vibrator physically coupled to the collector.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0080] FIG. 1 shows a system for implementing a polishing method according to one embodiment.

[0081] FIG. 2A shows a mechanism of transmission of the electricity between the electric source and the metal surface by means of net charge of the particles.

[0082] FIG. 2B shows a mechanism of transmission of the electricity between the electric source and the metal surface by means of electric conductivity by contact.

[0083] FIG. 2C shows a mechanism of transmission of the electricity between the electric source and the metal surface by means of electric conductivity by means of voltaic arches.

[0084] FIG. 3 shows a system for in line surface treatment.

[0085] FIG. 4 shows an outline of a portable device for surface treatment.

[0086] FIG. 5 shows a surface treatment system incorporated inside a cabin.

DETAILED DESCRIPTION

[0087] Disclosed hereafter are several example cases of surface treatment. The examples are in no way intended to limit the scope of the invention.

Embodiment 1

[0088] The device comprises a particles 9 delivery deposit 7 the exit of which is connected to a copper duct acting as electrode 3, in turn connected to an electric source 2. The particles 9 fall by gravity in a continuous manner down to the surface to be treated 1 which is connected to the electric source 2 through the counter electrode. The particles 9 fall, with prior contact with the part, down a collector 6 for their later recirculation by means of a recirculation system 5. As well the particles delivery deposit 7 as the collector 6 has a vibrator 8 available. A schematic representation can be seen in FIG. 1.

[0089] In an exemplary case, the particles (9) used are microporous gel particles of sulfonated polystyrene-divinylbenzene charged with an electrolyte solution that contains sulfuric acid at 4%. This prototype has been proved with different types of electric current: DC of 1 to 60 V; 50 Hz to 50,000 Hz at 0 to 220 V.

[0090] With these parameters, the polishing method for treatment of a steel 316 surface has been proved with different types of electric current: DC up to 35 kV, 50 Hz AC up to 15 kV.

[0091] The results of DC show a linear performance of the intensity with respect to the difference of potential. It is observed that after a treatment of 5 min effective at 30 kV, there is a reduction of the R3 of 0.37 to 0.34 μm in the area more exposed to the particles flow.

[0092] The results using AC at 50 Hz show a linear performance within the range of 0 to 5 kV. Increasing the voltage from that point does not produce an increase of the proportional intensity. This effect clearly indicates a change of mechanism in the transmission of the electric charge.

Device for the Treatment of in Line Surfaces

[0093] It consists of a device for in-line surface treatment. A schematic representation appears in the FIG. 3 that shows the device designed to treat metal plates. The device includes an electric source 3, a “curtain” system of application of particles 9, carrying system of the plate to be treated and a recirculation system 5 that collects the particles and deposits them in the delivery deposit 7.

[0094] The metal plate to be treated is located on a conveyor belt provided with vibration and connected to the electric source. At a point of the path of the conveyor belt there is a curtain-like particles shooter 9. The linear applicator produces a lineal shooting of particles 9 on the surface to be treated 1 that covers the full width of the plate that is sought to be treated. The plate moves through the curtain of particles at a suitable speed that provides it the time of treatment to obtain the expected finishes. Although not shown in FIG. 3, like the system of FIG. 1, the curtain-type particles shooter includes a vibrator 8 coupled to the delivery deposit to facilitate particle flow. In the slot of the particles exit there is a metal element, connected to the negative pole of the supply source that acts as electrode 3. The particles contact the electrode 3 before arriving on the surface to be treated 1. Close to the contact point a recirculation system 5 is applied that sucks the particles after they contact with the surface and deposit them in the delivery deposit 7.

Portable Device for Surfaces Treatment

[0095] It consists in a portable device for surfaces treatment 1. A schematic representation appears in FIG. 4. This device facilitates the joint carriage, such as, for example, with wheels.

[0096] The device includes a compressor and a pressurized air deposit, an electric source 2, a delivery deposit 7 of particles and a recirculation system 5.

[0097] The device can be connected to a plug, alternatively it can include a storage battery sufficient to provide the energy. The delivery deposit 7 of the particles 9 is located in a lower part and has an exit towards the particles delivery hose, the delivery deposit 7 can be provided with a vibrator 11 to facilitate the flow of particles 9. The particles 9 are propelled through the application hose 12 by means of compressed air coming from the compressor 13. The pressure necessary depends on the length and location of the application hose, a pressure between 3 and 10 bar provides good results. The application hose ends in a diffuser that allows the exit of part of the air, forcing the particles 9 to in contact with the treatment surface. The exit of the particles occurs through or in contact with an electrode 3 that can be an element of, for example, copper, stainless steel 316 or irradiated titanium, connected to the electric source 2, preferably to the negative pole, preferably with an ammeter for the control of the intensity. The application electrode 3 is located at a distance between 0.5 and 10 cm from the surface being treated, so that between the electrode and the surface there is a flow of particles to produce the passage of current. The final part of the exit of the particles is included within a collecting collector 6 that is located very close to or in contact with the surface to be treated 1. The particles collecting collector 6 is connected to a recirculation system 5 that comprises a second hose provided with suction that collects the particles from the collector 6 after their contact with the surface and delivers them newly to the particles delivery deposit 7. The surface to be treated 1 is preferably connected to the positive pole of the electric source 1 and by means an electric clamp 14. In order a worker polish non-accessible surfaces or to improve the accuracy, the system can include the use of a robotized arm.

[0098] The design of the system is figured out to occupy a compact volume and it contains elements, such as for example wheels or sliding elements that make them mobile.

[0099] The current applied depends on the composition of the surface to be treated and of the particles 9 used. For example, to treat a steel 316 surface, good results are achieved using particles of sulfonated polystyrene-divinylbenzene containing sulfuric acid at 4% with a DC of 12 V.

Device for the Treatment of Surfaces in Cabin

[0100] It consists of a device for the treatment of surfaces 1 in a closed cabin 4. A schematic representation can be seen in FIG. 5. The device includes an electric source 2, one or several exit ports of electrically active particles 9 with a plurality of electrodes 3, a system for anchoring the parts to be polished, a closed cabin 4 for the treatment and a recirculation system 5 that sucks/retrieves the particles from the collector 6, that in this example also acts as delivery deposit 7, and delivers the particles towards the exit ports that are directed towards the treatment surfaces.

[0101] The metallic parts to be polished are placed on frames within the cabin by means of suitable anchorages, so that they are connected to the electric source 2. The cabin 4 is provided with several exits of particles connected at their final section to electrodes 3. Shooting the particles 9 occurs by means of the use of compressed air, preferably within a range of 2 to 10 Bar, preferably between 4 and 6 bar.

[0102] The bottom of the cabin 4 that acts as collector 6, and thereafter as a delivery deposit 7 has a slope and the particles 9 are collected by a recirculation system (5) that carries them to the exits of particles.

[0103] The electric current applied depends on several factors such as of the type of material, the total area to be processed, the distance between the point of exit of the particles and the surface.

[0104] Additional embodiments are comprised in the following clauses.

[0105] Clause 1. Method for dry treatment of metal surfaces (1) by means of electrically active solid particles (9), the method comprising: [0106] Contact of the particles (9) with the electrode (3) of an electric source (2). [0107] Shooting of the particles (9) towards the metal surface to be treated. [0108] Transmission of electric charge of the particles to the metal surface to be treated.

[0109] Clause 2. Method for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to the clause 1, wherein the transmission of electricity between the electric source (2) and the metal surface (1) during the shooting step is by net charge of the particles (9).

[0110] Clause 3. Method for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to the clause 1, wherein the transmission of the electricity between the electric source (2) and the metal surface (1) during the shooting step is by electric conductivity by contact.

[0111] Clause 4. Method for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to the clause 1, wherein the transmission of electricity between the electric source (2) and the metal surface (1) during the shooting step is by electric conductivity by means of voltaic arches.

[0112] Clause 5. Method for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the preceding clauses, wherein the current that is applied to the electrode is a DC.

[0113] Clause 6. Method for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the preceding clauses 1-4, wherein the current applied to the electrode (3) is a current that contains positive sections and negative sections.

[0114] Clause 7. Method for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to the clause 4, wherein in the medium between the particles (9) there exists a conductive element that increases the conductivity between the particles by means of voltaic arches.

[0115] Clause 8. Method for dry treatment of metal surfaces (1) means of electrically active solid particles (9) according to the clause 7, wherein the element that favors the conductivity between the particles (9) by means of voltaic arches is a derivate of carbon, iodine, talc, cylinders and/or bars of gel.

[0116] Clause 9. Method for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to the clause 7, wherein the element that favors the conductivity between the particles (9) by means of voltaic arches is a source of ionizing radiation (ultraviolet, X-rays and y-rays), a non-ionzing source of radiation (microwaves), a nebulizer and generator of aerosol and/or an ultrasounds source.

[0117] Clause 10. Method for dry treatment of metal surfaces (1) by means of electrically active solid particles (0) according to any of the preceding clauses, wherein it comprises a step of use of abrasive particles, simultaneously or consecutively to the electrically active particles.

[0118] Clause 11. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9), wherein it comprises an electric source (2) with an electrode (3) that transmits electric charge to the electrically active solid the particles (9) and means for shooting electrically active solid particles on the surface to be treated (1).

[0119] Clause 12. Device for dry treatment of metal surfaces (1) means of electrically active solid particles (9) according to clause 11, wherein the electric: source (2) is connected to the surface to be treated (1) closing thus the electric circuit.

[0120] Clause 13. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the clauses 11-12, wherein propelling the electrically active solid particles (9) is carried out only by the force of gravity.

[0121] Clause 14. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the clauses 11-12, wherein propelling the electrically active solid particles (9) is carried out by means of a centrifugal system.

[0122] Clause 15. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the clauses 11-12, wherein propelling the electrically active solid particles (9) is carried out by means of compressed gas.

[0123] Clause 16. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the clauses 11-12, wherein propelling the electrically active solid particles (2) is cared out by means of a rod and crank system or an endless screw system.

[0124] Clause 17. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the clauses 11-16, wherein it forms part of an in-line assembly.

[0125] Clause 18. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the clauses 1-16, wherein it is a portable system.

[0126] Clause 19. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the clauses 11-16, wherein the device and the surface to be treated (1) are within a cabin (4).

[0127] Clause 20. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the clauses 11-19, wherein the device comprises a delivery deposit (7) of solid particles (9) previously to the contact with the electrode (3).

[0128] Clause 21. Device for dry treatment of metal surfaces (1) by means of electrically actin e solid particles (9) according to any of the clauses 11-20, wherein the device comprises a collector (6) of solid particles (9) after the have collided against the surface to be treated (1).

[0129] Clause 22. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to the clause 20, wherein the device comprises a recirculation system (5) of particles (9) from the collector (6) of solid particles to the delivery deposit (7).

[0130] Clause 23. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the clauses 11-22, wherein the device comprises a vibrator (8).

[0131] Clause 24. Device for dry treatment of metal surfaces (1) by means of electrically active solid particles (9) according to any of the clauses 11-23, wherein the deposit of exit of the particles comprises a diffuser.