High power pulse crushing tool and method

Abstract

The invention relates to a tool (1) for breaking rock by means of high-power pulses, comprising at least one energy recovery module (30-1) comprising at least one capacitor (C1, C2, C3) and a pair of secondary electrodes (30-1A, 30-1B), the at least one capacitor (C1) of the first energy recovery module (30-1) is electrically connected to the second electrode (20B) of the main electrode pair (20A, 20B) and to the ground (M), the secondary electrode pair (30-1A, 30-1B) comprises a first electrode (30-1A) and a second electrode (30-1B), the first electrode (30-1A) is electrically connected to a midpoint (M1) located between the second electrode (20B) of the main electrode pair (20A, 20B) and the at least one capacitor (C1), and the second electrode (30-1B) is electrically connected to the ground (M). The second electrode (30-1B) is placed facing the first electrode (30-1A) of the secondary electrode pair (30-1A, 30-1B), is spaced therefrom by a second electrode pitch (D2), and is electrically connected to the ground (M).

Description

Technical Field

[0001] The present invention relates to the field of high-power pulse fragmentation, and more particularly to a high-power pulse fragmentation tool and a high-power pulse fragmentation method. Background Art

[0002] High-power pulse rock crushing is to place a piece of rock between two electrodes and apply high voltage (e.g., high voltage on the order of several kilovolts to several hundred kilovolts) to induce extremely short electrical discharges (e.g., discharges on the order of microseconds). Such discharges generate tensile and compressive shock stresses, which effectively disintegrate and fracture the rock.

[0003] Among the existing crushing tool solutions, an example of a crushing tool is described in document US4540127, which includes a generator electrically connected to two electrodes. Figure 1 ] shows an electrical schematic diagram of such a tool 200. The generator 210 includes: an equivalent capacitor 211, representing a high voltage source, which is connected to the ground M; an equivalent resistor 212 electrically connected in series with the equivalent capacitor 211; an equivalent inductor 213 electrically connected in series with the equivalent resistor 212; and a two-position switch 214, one end of which is electrically connected in series with the equivalent inductor 213, and the other end of which is electrically connected in series with the first electrode 215 of the electrode pair, and the second electrode 216 of the electrode pair is electrically connected to the ground M.

[0004] When the on-off switch 214 of the generator 210 is closed, a discharge is generated in the space between the electrodes 215, 216 (usually referred to as the "electrode gap" in which liquid and / or solid is present). The discharge generates plasma and induces pressure waves in the liquid and / or solid.

[0005] However, the load resistance formed by the liquid and / or solid may vary significantly over time, resulting in energy losses, in part because a significant portion of the energy (called "undissipated energy", typically between 50% and 80% of the total energy of the applied voltage) is not converted into shock waves.

[0006] Therefore, there is a need for a simple and effective solution which at least partially remedies these drawbacks. Summary of the invention

[0007] To this end, a first object of the present invention is to provide a tool for crushing rocks by high-power pulses, the tool comprising a generator and a main electrode pair, the generator comprising a high-voltage source, one end of the high-voltage source being electrically connected to the ground, and the other end being connected in series with at least a double-position switch, the switch being electrically connected to a first electrode of the main electrode pair, the second electrode of the main electrode pair being placed facing the first electrode and spaced apart from it by a distance called an "electrode spacing", the tool being characterized in that it comprises at least one energy recovery module, the at least one energy recovery module comprising at least one capacitor and a secondary electrode pair, at least one capacitor of the first energy recovery module being electrically connected at one end to the second electrode of the main electrode pair, and at the other end to the ground, the secondary electrode pair of the first energy recovery module comprising a first electrode and a second electrode, the first electrode being electrically connected to a midpoint between the second electrode of the main electrode pair and the at least one capacitor, the second electrode being placed facing the first electrode of the secondary electrode pair, spaced apart from it by a second electrode spacing and electrically connected to the ground.

[0008] At least one capacitor is capable of recovering the energy not dissipated in the first discharge to trigger a second discharge (and so on according to the number of energy recovery modules used), thereby preventing this energy from being dissipated and lost in the circuit. In addition, by triggering multiple discharges, the tool is able to effectively break the rock. The tool of the present invention is particularly suitable for configurations where the generator and the load are not electrically matched. The use of a switch can ensure that the voltage at the electrode ends of the main electrode pair rises rapidly.

[0009] One or more energy recovery modules can be used in cascade.

[0010] More specifically, the tool may include N energy recovery modules, where N is a natural number greater than or equal to 1. The high voltage source of the tool must be calibrated so that the undissipated voltage collected by at least one capacitor can redefine a voltage greater than or equal to the breakdown threshold of the secondary electrode pair, and so on when multiple energy recovery modules are cascaded. For example, the voltage delivered by the high voltage source must be selected so that at least 80% of its value (which corresponds to the voltage defined by the energy collected in at least one capacitor of the first energy recovery module) constitutes a value greater than the electrode breakdown threshold of the secondary electrode pair.

[0011] In one embodiment, the tool includes a single energy recovery module.

[0012] In another embodiment, the tool includes a plurality of energy recovery modules connected in cascade to increase the efficiency of the tool.

[0013] Advantageously, the tool comprises a second energy recovery module, which comprises at least one capacitor and a secondary electrode pair, wherein one end of the at least one capacitor of the second energy recovery module is electrically connected to the second electrode of the secondary electrode pair of the first energy recovery module, and the other end is electrically connected to the ground, the secondary electrode pair of the second energy recovery module comprises a first electrode and a second electrode, the first electrode is electrically connected to the midpoint between the second electrode of the secondary electrode pair of the first energy recovery module and the at least one capacitor of the second energy recovery module, and the second electrode is placed facing the first electrode of the secondary electrode pair of the second energy recovery module, separated from it by a third electrode spacing and electrically connected to the ground.

[0014] More advantageously, the tool comprises a third energy recovery module, which comprises at least one capacitor and a secondary electrode pair, wherein one end of the at least one capacitor of the third energy recovery module is electrically connected to the second electrode of the secondary electrode pair of the second energy recovery module, and the other end is electrically connected to the ground, and the secondary electrode pair of the third energy recovery module comprises a first electrode and a second electrode, the first electrode being electrically connected to a midpoint between the second electrode of the secondary electrode pair of the second energy recovery module and at least one capacitor of the third energy recovery module, and the second electrode being placed facing the first electrode of the secondary electrode pair of the third energy recovery module, spaced apart from the first electrode by a fourth electrode spacing and electrically connected to the ground.

[0015] In one embodiment, the at least one capacitor of the energy recovery module comprises a single capacitor.

[0016] In another embodiment, the at least one capacitor of the energy recovery module comprises a plurality of capacitors connected in series and / or in parallel.

[0017] In one embodiment, each energy recovery module comprises a switch, such as a two-position switch, connected between at least one capacitor and the first electrode of the secondary electrode pair to enable the at least one capacitor to be fully discharged while preventing the charging of at least one capacitor of the next energy recovery module (cascade connection).

[0018] In one embodiment, each energy recovery module comprises an inductor, such as a coil, connected between at least one capacitor and a first electrode of the secondary electrode pair.

[0019] According to one aspect of the invention, the generator delivers a voltage between 1 and 300 kV, preferably between 50 and 300 kV, even more preferably about 180 kV.

[0020] The invention also relates to a method for recovering high power pulse energy for rock crushing, the method comprising the following steps: - controlling the first discharge between the first electrode and the second electrode of the main electrode pair, - recovering part of the energy of the first discharge by means of at least one capacitor connected between the second electrode of the main electrode pair and ground, - triggering a second discharge between the first and second electrodes of the secondary electrode pair.

[0021] In one embodiment, the method further comprises the step of recovering part of the energy of the second discharge by at least one second capacitor connected between the second electrode of the secondary electrode pair and the ground.

[0022] In one embodiment, the method further comprises triggering a third discharge between the first electrode and the second electrode of the secondary electrode pair of the second energy recovery module.

[0023] In one embodiment, the method further comprises the step of recovering part of the energy of the third discharge by at least one third capacitor connected between the second electrode of the secondary electrode pair of the second energy recovery module and the ground.

[0024] In one embodiment, the method further comprises triggering a fourth discharge between the first electrode and the second electrode of the secondary electrode pair of the third energy recovery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features and advantages of the present invention will become apparent from the following description. This description is for illustrative purposes only and should be read in conjunction with the accompanying drawings, in which: [ Figure 1 ] schematically illustrates an embodiment of a prior art system.

[0026] [ Figure 2 ] schematically shows a first embodiment of the system according to the present invention.

[0027] [ Figure 3 ] schematically shows a second embodiment of the system according to the present invention.

[0028] [ Figure 4 ] schematically shows a third embodiment of the system according to the present invention.

[0029] [ Figure 5 ] schematically shows a fourth embodiment of the system according to the present invention.

[0030] [ Figure 6 ] schematically shows a fifth embodiment of the system according to the present invention.

[0031] [ Figure 7 ] schematically shows a sixth embodiment of the system according to the present invention.

[0032] [ Figure 8 ] schematically shows a first embodiment of the method according to the present invention.

[0033] [ Fig. 9 ] schematically shows a second embodiment of the method according to the present invention.

[0034] [ Fig.10 ] schematically shows a third embodiment of the method according to the present invention. DETAILED DESCRIPTION

[0035] Tool 1 Figures 2 to 4 Three electrical schematic examples of a high power pulse rock breaking tool 1 according to the invention are shown.

[0036] The tool 1 comprises a generator 10, a pair of main electrodes 20A, 20B, and at least one energy recovery module 30-1, 30-2, 30-3.

[0037] The generator 10 includes a high voltage source 110, one end of which is electrically connected to the ground M, and the other end of which is serially connected to at least one two-position switch 120. An equivalent resistor 114 and an equivalent inductor 116 are electrically connected in series between the high voltage source 110 and the switch 120.

[0038] The high voltage source 110 delivers a voltage between 1 and 300 kV, preferably between 50 and 300 kV, for example between 170 and 200 kV.

[0039] The switch 120 is electrically connected to the first electrode 20A of the main electrode pair 20A, 20B.

[0040] The second electrode 20B of the main electrode pair 20A, 20B is placed facing the first electrode 20A of the main electrode pair 20A, 20B and is separated therefrom by a distance D1 referred to as the "electrode spacing" 20A, 20B.

[0041] Each energy recovery module 30-1, 30-2, 30-3 includes at least one capacitor C1, C2, C3 and electrode pairs (30-1A, 30-1B), (30-2A, 30-2B), (30-3A, 30-3B). Each capacitor C1, C2, C3 recovers part of the energy generated by the discharge of the electrode pairs (20A, 20B), (30-1A, 30-1B), (30-2A, 30-2B) to which it is connected, so as to prevent the energy from being lost through circuit dissipation. At least one capacitor C1, C2, C3 is a single capacitor, or includes one or more capacitors connected in series and / or in parallel, which are electrically equivalent to a single equivalent capacitor.

[0042] In the following, for the sake of clarity, each energy recovery module 30 - 1 , 30 - 2 , 30 - 3 includes a single capacitor C1 , C2 , C3 .

[0043] Example 1 exist[ Figure 2 ] In the example shown in FIG. 1 , the tool 1 comprises a first single energy recovery module 30 - 1 .

[0044] The first energy recovery module 30 - 1 includes a capacitor C1 and an electrode pair 30 - 1A, 30 - 1B.

[0045] The capacitor C1 has one end electrically connected to the second electrode 20B of the main electrode pair 20A, 20B, and the other end electrically connected to the ground M.

[0046] The electrode pair 30 - 1A, 30 - 1B of the first energy recovery module 30 - 1 includes a first electrode 30 - 1A electrically connected to a midpoint M1 between the second electrode 20B of the main electrode pair 20A, 20B and the capacitor C1 .

[0047] The electrode pair 30 - 1A, 30 - 1B of the first energy recovery module 30 - 1 further includes a second electrode 30 - 1B disposed facing the first electrode 30 - 1A, spaced apart from the first electrode 30 - 1A by a second electrode distance D2 and electrically connected to the ground M.

[0048] Example 2 exist[ Figure 3 ] In the example shown in FIG. 1 , the tool 1 comprises two energy recovery modules 30 - 1 and 30 - 2 connected in cascade.

[0049] The first energy recovery module 30 - 1 is the same as that shown in Example 1.

[0050] The second energy recovery module 30 - 2 includes a capacitor C2 and an electrode pair 30 - 2A, 30 - 2B.

[0051] One end of the capacitor C2 is electrically connected to the second electrode 30 - 1B of the electrode pair 30 - 1A, 30 - 1B of the first energy recovery module 30 - 1 , and the other end of the capacitor C2 is electrically connected to the ground M.

[0052] The electrode pair 30-2A, 30-2B of the second energy recovery module 30-2 includes a first electrode 30-2A electrically connected to a midpoint M2 between the second electrode 30-1B of the electrode pair 30-1A, 30-1B of the first energy recovery module 30-1 and the capacitor C2.

[0053] The electrode pair 30 - 2A, 30 - 2B of the second energy recovery module 30 - 2 further includes a second electrode 30 - 2B disposed facing the first electrode 30 - 2A, spaced apart therefrom by a third electrode interval D3 and electrically connected to the ground M.

[0054] Example 3 exist[ Figure 4 ] In the example shown in FIG. 1 , the tool 1 comprises three energy recovery modules 30 - 1 , 30 - 2 and 30 - 3 connected in cascade.

[0055] The first energy recovery module 30 - 1 is the same as the first energy recovery module 30 - 1 in Examples 1 and 2. The second energy recovery module 30 - 2 is the same as the second energy recovery module 30 - 2 in Example 2.

[0056] The third energy recovery module 30 - 3 includes a capacitor C3 and an electrode pair 30 - 3A, 30 - 3B.

[0057] One end of the capacitor C3 is electrically connected to the second electrode 30 - 2B of the electrode pair 30 - 2A, 30 - 2B of the second energy recovery module 30 - 2 , and the other end of the capacitor C3 is electrically connected to the ground M.

[0058] The electrode pair 30-3A, 30-3B of the third energy recovery module 30-3 includes a first electrode 30-3A electrically connected to a midpoint M3 between the second electrode 30-2B of the electrode pair 30-2A, 30-2B of the second energy recovery module 30-2 and the capacitor C3.

[0059] The electrode pair 30 - 3A, 30 - 3B of the third energy recovery module 30 - 3 further includes a second electrode 30 - 3B which is placed facing the first electrode 30 - 3A, spaced apart from the first electrode 30 - 3A by a fourth electrode distance D4 and electrically connected to the ground M.

[0060] In other embodiments, the tool 1 according to the invention may comprise more than three energy recovery modules 30 - 1 , 30 - 2 and 30 - 3 .

[0061] Figures 5 to 7 Three further embodiments are shown.

[0062] exist[ Figure 5 ], the schematic diagram of tool 1 is the same as [ Figure 2 ], but a coil L1 is added between the midpoint M1 and the first electrode 30-1A of the electrode pair 30-1A, 30-1B of the first energy recovery module 30-1. The coil L1 can be a discrete element or any suitable inductance element. The purpose of the coil L1 is to resonate the voltage when energy is transferred between the capacitor C1 and the capacitor C2, so that the capacitor C2 is charged to the same voltage as the capacitor C1.

[0063] exist[ Figure 6 ], the schematic diagram of tool 1 is the same as [ Figure 3], but a coil L1 is added between the midpoint M1 and the first electrode 30-1A of the electrode pair 30-1A, 30-1B of the first energy recovery module 30-1, and a coil L2 is added between the midpoint M2 and the first electrode 30-2A of the electrode pair 30-2A, 30-2B of the second energy recovery module 30-2. Coils L1 and L2 can be discrete elements or any type of suitable inductive element. The purpose of coils L1 and L2 is to resonate the voltage when energy is transferred between the capacitor of the previous module and the capacitor of the next module, so that the capacitor of the next module is charged to the same voltage as the capacitor of the previous module.

[0064] exist[ Figure 7 ], the schematic diagram of tool 1 is the same as [ Figure 4 ] is the same as in the above, but a coil L1 is added between the midpoint M1 and the first electrode 30-1A of the electrode pair 30-1A, 30-1B of the first energy recovery module 30-1, a coil L2 is added between the midpoint M2 and the first electrode 30-2A of the electrode pair 30-2A, 30-2B of the second energy recovery module 30-2, and a coil L3 is added between the midpoint M3 and the first electrode 30-3A of the electrode pair 30-3A, 30-3B of the third energy recovery module 30-3. Coils L1, L2 and L3 can be discrete elements or any type of suitable inductive elements. The purpose of coils L1, L2 and L3 is to resonate the voltage when energy is transferred between the capacitor of the previous module and the capacitor of the next module, so that the capacitor of the next module is charged to the same voltage as the capacitor of the previous module.

[0065] Implementation Example First embodiment This first embodiment relates to Example 1 and refers to [ Figure 8 ] for description.

[0066] First, as a prerequisite, a piece of rock is placed in the tool so that the rock extends between each electrode pair (20A, 20B), (30-1A, 30-1B).

[0067] In step E1 , the switch 120 is controlled to be closed to apply a voltage from the high voltage source 110 between the first electrode 20A and the second electrode 20B of the main electrode pair 20A, 20B, the voltage being greater than the breakdown threshold, to induce a first discharge in the rock.

[0068] In step E2, capacitor C1 then recovers part of the energy from the first discharge, and when the voltage across capacitor C1 reaches the charging threshold, a second discharge is induced in the rock between the first electrode 30-1A and the second electrode 30-1B of the electrode pair 30-1A, 30-1B of the first energy recovery module 30-1 in step E3.

[0069] Then, the control switch 120 is turned off to prepare for the next firing at the level of the electrodes 20A, 20B.

[0070] Second embodiment This second embodiment relates to Example 2 and refers to [ Fig. 9 ] for description.

[0071] First, a piece of rock is placed in the tool between each electrode pair (20A, 20B), (30-1A, 30-1B), (30-2A, 30-2B). The rock pieces may be different. For example, a conveyor belt may be used, on which the rock pieces circulate, with multiple electrode pairs placed at different axial positions around the conveyor belt.

[0072] In step E1 , the switch 120 is controlled to be closed to apply a voltage from the high voltage source 110 between the first electrode 20A and the second electrode 20B of the main electrode pair 20A, 20B, the voltage being greater than the breakdown threshold, to induce a first discharge in the rock.

[0073] In step E2, capacitor C1 then recovers part of the energy of the first discharge, and when the voltage across capacitor C1 reaches the charging threshold, a second discharge is induced in the rock between the first electrode 30-1A and the second electrode 30-1B of the electrode pair 30-1A, 30-1B of the first energy recovery module 30-1 in step E3.

[0074] Then, in step E4, capacitor C2 recovers part of the energy of the second discharge, and when the voltage across capacitor C2 reaches the charging threshold, in step E5, a third discharge is triggered in the rock between the first electrode 30-2A and the second electrode 30-2B of the electrode pair 30-2A, 30-2B of the second energy recovery module 30-2.

[0075] Then, the control switch 120 is turned off to prepare for the next firing at the level of the electrodes 20A, 20B.

[0076] Third embodiment This third embodiment relates to Example 3 and refers to [ Fig.10 ] for description.

[0077] First, as a prerequisite, a piece of rock is placed in the tool so that the rock extends between each electrode pair (20A, 20B), (30-1A, 30-1B), (30-2A, 30-2B), (30-3A, 30-3B).

[0078] In step E1 , the switch 120 is controlled to be closed to apply a voltage from the high voltage source 110 between the first electrode 20A and the second electrode 20B of the main electrode pair 20A, 20B, the voltage being greater than the breakdown threshold, to induce a first discharge in the rock.

[0079] In step E2, capacitor C1 then recovers part of the energy of the first discharge, and when the voltage across capacitor C1 reaches the charging threshold, a second discharge is induced in the rock between the first electrode 30-1A and the second electrode 30-1B of the electrode pair 30-1A, 30-1B of the first energy recovery module 30-1 in step E3.

[0080] Then, in step E4, capacitor C2 recovers part of the energy of the second discharge, and when the voltage across capacitor C2 reaches the charging threshold, in step E5, a third discharge is triggered in the rock between the first electrode 30-2A and the second electrode 30-2B of the electrode pair 30-2A, 30-2B of the second energy recovery module 30-2.

[0081] Then, in step E6, capacitor C3 recovers part of the energy of the third discharge, and when the voltage across capacitor C3 reaches the charging threshold, in step E7, a fourth discharge is triggered in the rock between the first electrode 30-3A and the second electrode 30-3B of the electrode pair 30-3A, 30-3B of the third energy recovery module 30-3.

[0082] Then, the control switch 120 is turned off to prepare for the next firing at the level of the electrodes 20A, 20B.

[0083] It goes without saying that in order to trigger cascade discharge, the size of each capacitor C1, C2, C3 of each energy recovery module 30-1, 30-2, 30-3 must be able to store a certain amount of energy, the voltage defined by this energy being at least equal to the breakdown threshold between the electrodes of the electrode pair of the energy recovery modules 30-1, 30-2, 30-3.

[0084] According to the tool and method of the present invention, each capacitor C1, C2, C3 of each energy recovery module 30-1, 30-2, 30-3 collects part of the energy that is not dissipated between the electrodes of the electrode pair located upstream, which enables discharge to be induced between the electrodes of the electrode pair located downstream of the capacitors C1, C2, C3. Therefore, the tool and method according to the present invention can recover part of the energy that is not dissipated by the discharge between the electrodes of the upstream electrode pair to prevent its loss.

[0085] In another embodiment, each energy recovery module 30-1, 30-2, 30-3 may include a switch connected between a capacitor and a first electrode of a secondary electrode pair of said module, which switch will be controlled to achieve a complete discharge of said capacitor, avoiding charging of the capacitor of the next energy recovery module (cascade connection). More precisely, when the voltage in the capacitor reaches its maximum value (corresponding to the maximum stored energy), the switch initially in an open state is controlled to close.

[0086] The present invention thus makes it possible to optimize the utilization of the breakdown energy between the electrodes by recovering part of the dissipated energy for reuse.

Claims

1. A tool (1) for breaking rocks by high-power pulses, the tool (1) comprising a generator (10) and a main electrode pair (20A, 20B), the generator (10) comprising a high-voltage source (110), one end of the high-voltage source (110) being electrically connected to the ground (M), and the other end being connected in series with at least a two-position switch (120), the switch (120) being electrically connected to a first electrode (20A) of the main electrode pair (20A, 20B), the second electrode (20B) of the main electrode pair (20A, 20B) being placed facing the first electrode (20A) and being spaced apart from the first electrode (20A) by a distance (D1) called "electrode spacing", the tool (1) being characterized in that it comprises at least one energy recovery module (30-1, 30-2, 30-3), the at least one energy recovery module (30-1, 30-2, 30-3) comprising at least one capacitor (C1, C2, C3) and a secondary electrode pair (30-1A, 30-2, 30-3) 1B; 30-2A, 30-2B; 30-3A, 30-3B), one end of the at least one capacitor (C1) of the first energy recovery module (30-1) is electrically connected to the second electrode (20B) of the main electrode pair (20A, 20B), and the other end is electrically connected to the ground (M), the secondary electrode pair (30-1A, 30-1B) of the first energy recovery module (30-1) comprises a first electrode (30-1A) and a second electrode (30-1B), the first electrode (30-1A) is electrically connected to a midpoint (M1) between the second electrode (20B) of the main electrode pair (20A, 20B) and the at least one capacitor (C1), the second electrode (30-1B) is placed facing the first electrode (30-1A) of the secondary electrode pair (30-1A, 30-1B), is spaced apart from the first electrode (30-1A) by a second electrode spacing (D2) and is electrically connected to the ground (M).

2. The tool (1) according to claim 1, comprising a single energy recovery module (30-1).

3. The tool (1) according to claim 1, comprising a plurality of energy recovery modules connected in cascade.

4. The tool (1) according to the preceding claim, comprises a second energy recovery module (30-2), the second energy recovery module (30-2) comprising at least one capacitor (C2) and a secondary electrode pair (30-2A, 30-2B), one end of the at least one capacitor (C2) of the second energy recovery module (30-2) being electrically connected to the second electrode (30-1B) of the secondary electrode pair (30-1A, 30-1B) of the first energy recovery module (30-1), and the other end being electrically connected to the ground (M), the secondary electrode pair (30-2A, 30-2B) of the second energy recovery module (30-2) comprising a first electrode A first electrode (30-2A) and a second electrode (30-2B), the first electrode (30-2A) being electrically connected to a midpoint (M2) between the second electrode (30-1B) of the secondary electrode pair (30-1A, 30-1B) of the first energy recovery module (30-1) and the at least one capacitor (C2) of the second energy recovery module (30-2), the second electrode (30-2B) being placed facing the first electrode (30-2A) of the secondary electrode pair (30-2A, 30-2B) of the second energy recovery module (30-2), being spaced apart from the first electrode (30-2A) by a third electrode spacing (D3) and being electrically connected to the ground (M).

5. The tool (1) according to the preceding claim comprises a third energy recovery module (30-3), the third energy recovery module (30-3) comprising at least one capacitor (C3) and a secondary electrode pair (30-3A, 30-3B), one end of the at least one capacitor (C3) of the third energy recovery module (30-3) being electrically connected to the second electrode (30-2B) of the secondary electrode pair (30-2A, 30-2B) of the second energy recovery module (30-2), and the other end being electrically connected to the ground (M), the secondary electrode pair (30-3A, 30-3B) of the third energy recovery module (30-3) comprising a first electrode A first electrode (30-3A) and a second electrode (30-3B), the first electrode (30-3A) being electrically connected to a midpoint (M3) between the second electrode (30-2B) of the secondary electrode pair (30-2A, 30-2B) of the second energy recovery module (30-2) and the at least one capacitor (C3) of the third energy recovery module (30-3), the second electrode (30-3B) being placed facing the first electrode (30-3A) of the secondary electrode pair (30-3A, 30-3B) of the third energy recovery module (30-3), being spaced apart from the first electrode (30-3A) by a fourth electrode spacing (D4) and being electrically connected to the ground (M).

6. The tool (1) according to any one of the preceding claims, wherein each energy recovery module (30-1, 30-2, 30-3) comprises a single capacitor.

7. The tool (1) according to any of the preceding claims, wherein each energy recovery module (30-1, 30-2, 30-3) comprises a plurality of capacitors connected in series and / or in parallel.

8. A tool (1) according to any one of the preceding claims, wherein at least one of the energy recovery modules (30-1, 30-2, 30-3) comprises a coil (L1, L2, L3), and the coil (L1, L2, L3) is connected between the at least one capacitor (C1, C2, C3) and the first electrode (30-1A, 30-1B; 30-2A, 30-2B; 30-3A, 30-3B) of the secondary electrode pair (30-1A, 30-2A, 30-3A).

9. A tool (1) according to any of the preceding claims, wherein each energy recovery module (30-1, 30-2, 30-3) comprises a switch connected between the at least one capacitor (C1, C2, C3) and the first electrode (30-1A, 30-1B; 30-2A, 30-2B; 30-3A, 30-3B) of the module (30-1, 30-2, 30-3).

10. The tool (1) according to any of the preceding claims, wherein the generator delivers a voltage between 1 and 300 kV, preferably between 50 and 300 kV, even more preferably about 180 kV.

11. A method for recovering high power pulse energy to break rocks, the method The following steps are involved: - controlling (E1) a first discharge between a first electrode (20A) and a second electrode (20B) of a main electrode pair (20A, 20B), - recovering (E2) part of the energy of said first discharge by means of at least one capacitor (C1) connected between said second electrode (20B) of said main electrode pair (20A, 20B) and ground (M), - triggering (E3) a second discharge between the first electrode (30-1A) and the second electrode (30-1B) of the secondary electrode pair (30-1A, 30-1B) of the first energy recovery module (30-1).

12. The method according to the preceding claim, further comprising the step of recovering (E4) part of the energy of the second discharge by means of at least one second capacitor (C2) connected between the second electrode (30-1B) of the secondary electrode pair (30-1A, 30-1B) of the first energy recovery module (30-1) and the ground (M). 13 . The method according to claim 11 , further comprising triggering a third discharge between the first electrode and the second electrode of the secondary electrode pair of the second energy recovery module.

14. The method according to any one of claims 11 to 13, further comprising the step of recovering part of the energy of the third discharge by at least one third capacitor connected between the second electrode of the secondary electrode pair of the second energy recovery module and the ground. 15 . The method according to claim 11 , further comprising triggering a fourth discharge between the first electrode and the second electrode of the secondary electrode pair of the third energy recovery module.

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