Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
  • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
  • B02C19/00—Other disintegrating devices or methods
  • B02C19/18—Use of auxiliary physical effects, e.g. ultrasonic waves or irradiation, for disintegrating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
  • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
  • B02C19/00—Other disintegrating devices or methods
  • B02C19/18—Use of auxiliary physical effects, e.g. ultrasonic waves or irradiation, for disintegrating
  • B02C2019/183—Crushing by discharge of high electrical energy
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H1/00—Electrical discharge machining, i.e. removing metal with a series of rapidly recurring electrical discharges between an electrode and a workpiece in the presence of a fluid dielectric
  • B23H1/04—Electrodes specially adapted therefor or their manufacture
  • B23H1/06—Electrode material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H9/00—Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects
  • B23H9/001—Disintegrating

Definitions

• the present invention relates to the field of high-power electric discharge tools and more particularly relates to a pulsed high-power electric discharge tool.
• Such tools are used, for example, to grind rock on the surface to reduce it into small pieces.
• the electrodes used are large and made of resistant materials such as, for example, steel or copper-tungsten type alloys.
• Existing electrodes are in the form of an elongated one-piece body comprising a cylindrical-shaped fixing end and a substantially rounded firing end.
• One of the aims of the invention is to provide a simple and effective solution for a high pulsed power tool.
• Another aim of the invention is to provide a high pulsed power tool solution comprising reliable and durable electrodes.
• the invention firstly relates to a high-power pulsed electrical discharge tool, said tool comprising a plurality of electrodes mounted on an electrode holder, each of the electrodes comprising an elongated body, fixed on said electrode holder, comprising a fixing end and a firing end configured to allow the departure or arrival of an electric arc, each electrode being remarkable in that, the body being made of a first material, it comprises a tip made of a second material, different from the first material, mounted at the firing end of the body.
• the use of a specific tip significantly slows down the wear of the firing end of the body, thus allowing more shots to be made.
• the tip can be changed to extend the life of the electrode.
• the tip is in the form of an insert housed coaxially with the body in a receiving cavity formed in the firing end, preferably so as to come flush with the end of body shot.
• an insert is securely fixed on the firing end of the body, which allows the electrode to wear out slowly.
• the tip is in the form of a solid cylinder mounted coaxially on the firing end of the body, protruding from said firing end by a predetermined distance.
• the first material is a metal or a metal alloy adapted to resist the mechanical stresses generated by the electric arc.
• the second material is a metal or a metal alloy adapted to resist the mechanical stresses generated by the electric arc.
• the second material has a melting point greater than 2500°C in order to reduce erosion.
• the second material is chosen from rhenium and/or molybdenum and/or tungsten in order to reduce erosion.
• the first material is ductile, which allows it to resist shocks generated by electrical discharges.
• the first material is a metal
• the first material is steel.
• the body is in one piece.
• the firing end of the body is substantially rounded.
• the fixing end of the body has a cylindrical shape.
• the invention also relates to a method of manufacturing a tool as presented previously, said tool comprising an electrode holder, said method comprising, for each electrode, the steps of:
• the tool can for example be a tool for electro-hydraulic forming (Electro-Hydraulic Forming or EHF) or a grinding cell by direct or indirect electro-hydraulic effect (in the direct effect, the rock is positioned between the electrodes and the electric discharge crosses the rock, in the indirect effect, the rock is not located between the electrodes, the electric discharge occurs in the water, generating a shock wave which will impact the rock).
• EHF Electro-Hydraulic Forming
• Tool 1 comprises an electrode holder 10 and electrodes 20, mounted on said electrode holder 10.
• the tool 1 comprises electrical means (not shown) configured to apply a high voltage, preferably between 10 and 300 kV for example, between the electrodes 20 in order to trigger an electrical discharge between said electrodes 20.
• the electrodes 20 operate in pairs (anode-cathode), as in the example of the , or more (for example an anode and several cathodes).
• the medium located between the electrodes 20, intended to undergo the shot(s), is a solid and/or gaseous medium.
• the tool 1 can for example be used to fracture or crush rock by delivering an electrical discharge generated by the application of high voltage between the electrodes 20. Such a tool 1 makes it possible, for example, to carry out several thousand shots.
• FIGS 2 and 3 illustrate two embodiments of an electrode 20 for the tool 1 according to the invention.
• Each electrode 20 comprises a body 210 and a tip 220.
• the body 210 has an elongated shape extending along a longitudinal axis X.
• the body 210 is in one piece.
• the body 210 is made of a first material which is ductile, that is to say which can be elongated, extended, stretched without breaking.
• the first material may be a metal or a metal alloy, for example steel.
• the body 210 includes a fixing end 210A and a firing end 210B.
• the fixing end 210A is configured to allow the fixing of the electrode on an electrode holder 10 of the tool 1.
• the firing end 210B is configured to allow the output of electrical energy to another electrode to form an arc synonymous with electrical discharge or the entry of electrical energy from an arc extending from another electrode.
• the firing end 210B has a substantially rounded shape on the circular periphery of its free part.
• the firing end 210B is configured to receive the tip 220.
• the tip 220 is fixed at the firing end 210B of the body 210.
• the end piece 220 is made of a second material, different from the first material.
• the second material is a metal or a metal alloy or a shrink alloy.
• the second material is chosen from rhenium, molybdenum, tungsten or an alloy of at least two of these three metals.
• the second material is ductile and has a melting point above 2500°C.
• the end piece 220 is in the form of a solid cylindrical insert, of rectangular longitudinal section, housed coaxially with the longitudinal axis X of the body 210 in a central receiving cavity 210B1, extending over a length L, also coaxially with the longitudinal axis the tip 220 has a length greater than 1 cm in order to improve its attachment to the body 210 and thus the resistance of the electrode 1.
• the end piece 220 is in the form of a solid cylindrical insert, of rectangular longitudinal section, housed coaxially with the longitudinal axis X of the body 210 in a central receiving cavity 210B1, extending over a length L, also coaxially with the longitudinal axis X of the body 210, formed in the firing end 210B.
• the tip 220 extends from the firing end 210B by a distance D.
• the distance D can for example be between 1 and 30 mm.
• the end piece 220 thus has a length (L+D).
• the example of the allows solidity and effective maintenance of the insert while the example of the makes it possible to increase the electric field at the end of the insert and thus reduce the time for creating the discharge, thus improving the efficiency of the intended application, for example rock crushing.
• the tool manufacturing method 1 firstly comprises the manufacturing of the electrode holder 10 in a step E0.
• the body 210 of each electrode 20 is manufactured in a step E1, for example by molding or machining, during which the receiving cavity 210B1 is formed in the firing end 210B of the body 210.
• the process comprises, still for each electrode 20, the manufacture of the tip 220, for example also by molding or machining, in a step E2.
• the method then comprises, still for each electrode 20, the assembly of the body 210 and the tip 220 in a step E3. More precisely, the tip 220 is fixed on the firing end 210B of the body 210.
• This fixing can for example be a forced assembly so that the tip 220 is securely fixed by friction on the firing end 210B of the body 210.
• the electrodes 20 are fixed on the electrode holder 10 in step E4.
• the tests carried out on the different types of electrodes show that the electrodes in the examples in Figures 2 and 3 sustainably resist several thousand shots (at least 5000 shots on average according to the tests), in particular by presenting at the end of the tests low wear compared to existing conventional solutions.
• the tip 220 therefore makes it possible to significantly increase the resistance of the high-power electrodes 20.

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• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Engineering & Computer Science (AREA)
• Food Science & Technology (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
• Surgical Instruments (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=85685199

Family Applications (1)

Country Status (4)

Family Cites Families (5)

• 2023
  • 2023-01-10 FR FR2300234A patent/FR3144767B1/fr active Active
  • 2023-12-22 WO PCT/EP2023/087690 patent/WO2024149611A1/fr not_active Ceased
  • 2023-12-22 EP EP23836883.1A patent/EP4648901A1/de active Pending
  • 2023-12-22 AU AU2023423465A patent/AU2023423465A1/en active Pending

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