A high-voltage pulse discharge rock breaking device

Abstract

The application discloses a high-voltage pulse discharge rock breaking device, and belongs to the technical field of high voltage. The device comprises a charging unit, an energy storage and pulse current forming unit, a pulse current transmission unit, a breaking unit and a time sequence triggering unit which are connected in sequence. The device realizes large-volume rock breaking by means of stage-by-stage breaking and time sequence discharge control to make the shock wave of the breaking unit superimposed. The charging unit converts low-voltage power frequency alternating current into high-voltage direct current to provide the required electric energy of the system. The energy storage and pulse current forming unit is used for storing the electric energy provided by the charging unit and releasing the electric energy through the time sequence triggering unit to form a pulse current. The pulse current transmission unit is used for transmitting the pulse current to the breaking unit. The breaking unit uses the pulse current to make a metal wire explode and break rocks. The time sequence triggering unit is used for controlling the energy release time sequence of the energy storage and pulse forming unit to realize the superposition of the shock wave and ensure the efficient breaking of rocks.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high voltage, and more particularly, relates to a high-voltage pulse discharge rock breaking device. BACKGROUND

[0002] The high-voltage pulse discharge rock breaking technology is a specific way of applying pulse power technology to rock breaking. A high-current density pulse current is applied to a metal wire, so that the metal wire is burned and vaporized in a microsecond level of time, and forms a plasma. The high-temperature plasma rapidly expands outward, and a strong shock wave is generated in a very short time. The stress intensity generated by the shock wave is greater than the tensile strength of the rock, so that the rock is broken. Through multiple stages of action, the rock is broken in a large volume.

[0003] The blasting method uses the huge energy released by explosives or other explosives to break rocks, and has good breaking effect, but has large disturbance to the original rock, is easy to cause damage to the surrounding rock, and has the disadvantages of low construction precision, uneven broken size, difficult surrounding rock support, etc. Based on the advantages of cutting, punching, rolling, grinding and other different mechanical rock breaking methods, but when encountering hard rock with high compressive strength, cutting and breaking are extremely difficult, and the main bottlenecks of mechanical rock breaking are tool wear, maintenance amount and low invasion rate. The existing rock breaking equipment based on pulse power technology has the disadvantages of low mechanical energy conversion efficiency, fast shock wave attenuation, and difficulty in realizing large-size rock breaking. SUMMARY

[0004] In view of the defects of the prior art, the purpose of the present application is to improve the demand. The high-voltage pulse discharge rock breaking device proposed in this paper solves the technical problems of large loss, low precision, fast shock wave attenuation and inability to realize large-size rock breaking of the existing rock breaking equipment.

[0005] To achieve the above purpose, the present application provides a high-voltage pulse discharge rock breaking device, which comprises a charging unit, an energy storage and pulse current forming unit, a pulse current transmission unit, a breaking unit and a time sequence triggering unit. The breaking unit shock wave is superimposed by stage breaking and time sequence discharge control to realize large-size rock breaking.

[0006] The charging unit is used to convert low-voltage power frequency alternating current into high-voltage direct current, and provide the required power of the system.

[0007] The energy storage and pulse current forming unit is used to store the power provided by the charging unit, and release the power through the time sequence triggering unit to form a pulse current.

[0008] The pulse current transmission unit is used to transmit the pulse current generated by the energy storage and pulse current forming unit to the breaking unit.

[0009] The wire explosion is performed by the pulse current transmitted by the pulse current transmission unit, the electric energy is converted into mechanical energy, and the rock is broken.

[0010] The timing trigger unit is used for controlling the timing of energy storage and energy release of the pulse forming unit, so as to ensure the efficient breaking of the rock.

[0011] Preferably, the charging unit adopts a series resonance constant current charging mode, and includes a low-frequency low-voltage rectifier circuit, an inverter, a resonance module, a transformer and a high-frequency high-voltage rectifier circuit. The power frequency low-voltage alternating current is rectified by the low-frequency low-voltage rectifier circuit, the inverter, the resonance module, the transformer and the high-frequency high-voltage rectifier circuit in sequence, and is inverted, resonant boosted and rectified again, and is then converted into high-voltage direct current required by the system.

[0012] Preferably, the energy storage and pulse current forming unit includes a plurality of energy storage and pulse current forming modules. The energy storage and pulse current forming module includes an energy storage capacitor, a freewheeling silicon stack, a wave adjustment inductor and a thyristor switch. The energy storage capacitor is used to store the current transmitted by the charging unit and form a pulse current through the thyristor switch. The pulse current waveform is adjusted by the energy storage capacitor and the wave adjustment inductor. The freewheeling silicon stack is connected in antiparallel with the energy storage capacitor to avoid damage to the energy storage capacitor caused by the reverse voltage formed at both ends of the energy storage capacitor. In order to improve the utilization efficiency of the shock wave and the rock breaking effect, the system energy should be injected before the shock wave is generated to the free surface and reflected back to the original point. Therefore, the wave adjustment inductor and the energy storage capacitor should satisfy the following relationship:

[0013]

[0014] wherein, L L is the inductance of the wave adjustment inductor, C C is the capacitance of the energy storage capacitor, l D is the distance from the breaking electrode to the free surface, v v is the sound speed of the rock.

[0015] Preferably, the pulse current transmission unit adopts a coaxial cable structure. In order to reduce the stray inductance and stray resistance of the system, the coaxial cable adopts a multi-core wire structure.

[0016] Preferably, the breaking unit includes a plurality of breaking modules. The breaking module includes a connecting unit, a discharge electrode, an electric explosion cylinder and a drill hole. The drill hole is generated by mechanical drilling, and the discharge electrode and the electric explosion cylinder are placed in the drill hole. The connecting unit realizes the connection between the breaking module and the pulse current transmission module.

[0017] Preferably, the discharge electrode transmits pulse current to the electric explosion cylinder, the discharge electrode adopts a coaxial structure and is reusable, polycarbonate is filled between the high-voltage electrode and the grounding electrode to realize insulation, the high-voltage electrode is made of tungsten copper alloy, and the grounding electrode is made of a pipe body of brass to avoid damage of the electrode by strong shock waves.

[0018] Preferably, the electric explosion cylinder comprises a wire and a shock wave propagation cylinder body, the wire explodes under pulse current and forms a plasma channel, the channel expands to generate a shock wave, and the shock wave propagation cylinder body is made of polyethylene material and has an outer diameter consistent with the inner diameter of the drill hole to transmit the shock wave to the rock, reduce the attenuation of the shock wave, and improve the rock breaking efficiency.

[0019] Preferably, the breaking modules of the breaking unit are placed at equal intervals on a surface parallel to the free surface (i.e. the edge of the rock) of the rock. The thyristor switches are discharged in sequence to make the corresponding electric explosion cylinder wires explode to generate shock waves, so that the adjacent breaking modules generate shock wave interference to improve the shock wave intensity and the rock breaking effect. The rock between the surface and the free surface is stripped after breaking, the surface forms a new free surface, and a stage of breaking is completed. The next stage of breaking unit is placed and placed in the above manner, and the large-volume rock is completely broken through the multi-stage breaking mode.

[0020] Preferably, the time sequence triggering unit comprises an optoelectronic conversion unit, a time sequence adjustment unit and a power amplification unit. The optoelectronic conversion unit is used to convert the control optical signal transmitted by the optical fiber into an electrical signal. The use of optical fiber for control signal transmission can effectively avoid strong electromagnetic interference in the pulse discharge process. The power amplification unit is used to amplify the electrical signal into a trigger signal to trigger the thyristor. The time sequence adjustment unit controls the conduction time of the thyristor switch to ensure that the electric explosion cylinders explode in sequence to generate shock waves, realize shock wave interference superposition, and improve the rock breaking effect. The delay time of adjacent electric explosion cylinders, i.e. the time sequence adjustment unit control signal delay time, should satisfy:

[0021]

[0022] wherein d is the distance between adjacent electric explosion cylinders, v is the sound velocity of the rock.

[0023] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0024] 1. The rock breaking system based on metal wire explosion provided by the application adjusts the current waveform by the joint action of the energy storage capacitor and the wave modulation inductor, so that the energy injection is realized within the time of the reflection of the shock wave to the original point, the shock wave energy conversion efficiency is improved, and the system energy loss is reduced.

[0025] 2. The rock breaking system based on metal wire explosion provided by the application adopts the combination of the discharge electrode and the electric explosion cylinder, realizes the reuse of the discharge electrode, and reduces the electrode loss and the rock breaking cost.

[0026] 3. The rock breaking system based on metal wire explosion provided by the application is that the metal wire in the electric explosion cylinder is surrounded by the polyethylene material, the outer diameter of the shock wave propagation cylinder body made of the polyethylene material is the same as the inner diameter of the drill hole, the shock wave generated by the expansion of the plasma channel is propagated to the rock through the high acoustic stiffness polyethylene material, the attenuation of the shock wave in the air is reduced, and the rock breaking effect of the shock wave is improved.

[0027] 4. The rock breaking system based on metal wire explosion provided by the application realizes the interference superposition of the shock wave by controlling the sequential triggering of the thyristor switch through the time sequence triggering system, and improves the rock breaking effect.

[0028] 5. The rock breaking system based on metal wire explosion provided by the application realizes the breaking of large-volume rock by the stage breaking mode, after the rock breaking of the previous stage is completed, the plane where the breaking unit is located becomes the free surface of the rock breaking of the next stage, and so on, so that the large-volume rock breaking is realized. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The structure schematic view of the high-voltage pulse discharge rock breaking device provided by the embodiment of the application;

[0030] Figure 2 The structure schematic view of the charging unit provided by the embodiment of the application;

[0031] Figure 3 The structure schematic view of the energy storage and pulse current forming module provided by the embodiment of the application;

[0032] Figure 4 The structure schematic view of the breaking module provided by the embodiment of the application;

[0033] Figure 5 The structure schematic view of the time sequence triggering unit provided by the embodiment of the application. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0035] The application discloses a high-voltage pulse discharge rock breaking device and a field application method. Figure 1 As shown in the figure, it comprises a charging unit 101, an energy storage and pulse current forming unit 102, a pulse current transmission unit 103, a breaking unit 104 and a time sequence triggering unit 105 connected in sequence. Through stage breaking and time sequence discharge control, the breaking unit shock wave is superimposed to realize large volume rock breaking.

[0036] The high-voltage conversion unit is used to convert low-voltage power frequency alternating current into high-voltage direct current to provide the required power of the system.

[0037] Specifically, as shown in the figure, Figure 2 The high-voltage conversion unit adopts a single-phase full-bridge LC series resonant converter, and a high-voltage constant-current charging device, which comprises a power frequency low-voltage rectifier circuit, an inverter, a high-frequency high-voltage rectifier circuit, a resonant circuit and a pulse transformer. The device realizes constant-current charging through the mode of rectification, inversion, resonant voltage boost and rectification again, reduces the size of the equipment and the charging time, and realizes accurate charging through feedback control. Preferably, the low-frequency low-voltage rectifier circuit selects a high-voltage silicon stack with a withstand voltage of 1kV, and the DC bus voltage is stabilized at 513V after LC filter loop filtering; the inverter realizes soft switching through fixed pulse width variable frequency control, and realizes voltage conversion through a 1:200 pulse transformer after series resonance; the high-frequency high-voltage rectifier circuit selects a high-frequency high-voltage silicon stack with a withstand voltage of 150kV to realize rectification due to high voltage level and high pulse frequency. Since the device has high voltage level, the withstand voltage of the resistor needs to be considered when selecting the resistor, and in addition, the resistor needs to be long enough, otherwise it is easy to occur surface discharge.

[0038] The energy storage and pulse current forming unit stores the power provided by the charging unit and controls the release of the power through the time sequence triggering unit to form a pulse current.

[0039] Specifically, the energy storage and pulse current forming unit comprises a plurality of energy storage and pulse current forming modules, and each energy storage and pulse current forming module comprises an energy storage capacitor 301, a freewheeling silicon stack 302, a wave modulation inductor 303 and a thyristor switch 304. The energy storage capacitor is used to store the current transmitted by the charging unit, and the thyristor switch is used to control the formation of the pulse current. The pulse current waveform is adjusted by the energy storage capacitor and the wave modulation inductor. The freewheeling silicon stack is connected in antiparallel with the energy storage capacitor to avoid the damage of the energy storage capacitor caused by the reverse voltage across the energy storage capacitor. In order to improve the shock wave utilization efficiency and the rock breaking effect, the system energy should be injected before the shock wave is generated to the free surface and reflected back to the original point. Therefore, the wave modulation inductor and the energy storage capacitor should satisfy the following relationship:

[0040]

[0041] wherein, L L is the inductance of the wave modulation inductor, C C is the capacitance of the energy storage capacitor, l D is the distance from the breaking electrode to the free surface, v v is the sound speed of the rock.

[0042] Preferably, the energy storage capacitor is a pulse capacitor with a rated voltage of 20 kV and a capacity of 20 μF. 20 capacitors are connected in parallel to form a capacitor with a capacity of 400 μF. When the charging voltage is 15 kV, the parallel capacitor stores 45 kJ of energy. The wave modulation inductor is made of a copper strip with a width of 150 mm and a thickness of 0.6 mm. The inductance value measured at 5 kHz is about 2 μH. The rated voltage of the thyristor switch and the freewheeling silicon stack is 20 kV, and the rated current is 150 kA.

[0043] The pulse current transmission unit adopts a coaxial cable structure. In order to reduce the stray inductance and stray resistance of the system, the coaxial cable adopts a multi-core structure. Specifically, the coaxial cable is selected to be a RC-50-17-17 type four-core coaxial cable with a length of 12 meters.

[0044] The breaking unit comprises a plurality of breaking modules, and each breaking module comprises a breaking electrode 401, a pulse current transmission unit 402 and a rock breaking unit 403. Figure 4The shown includes a connection unit 401, a discharge electrode 402, an electric explosion cylinder 403 and a drill hole 404. The drill hole is produced by mechanical drilling, and the discharge electrode and the electric explosion cylinder are placed in the drill hole, wherein the drill hole has a diameter of 30 mm and a depth of 90 cm. The connection unit realizes the connection of the crushing module and the pulse current transmission module. The discharge electrode transmits the pulse current to the electric explosion cylinder. The discharge electrode adopts a coaxial structure and can be reused. Polycarbonate is filled between the high-voltage electrode and the grounding electrode to realize insulation. In order to reduce electrode ablation, the high-voltage electrode is made of tungsten-copper alloy, and the grounding electrode is made of a pipe body made of brass to avoid damage to the electrode by strong shock waves. Specifically, the discharge electrode is 60 cm long, wherein the high-voltage electrode has a diameter of 5 mm, the grounding electrode has an outer diameter of 15 mm and an inner diameter of 10 mm, and polycarbonate is filled in the middle as insulation. The shock wave propagation cylinder of the electric explosion cylinder has an outer diameter of 30 mm, which is consistent with the inner diameter of the drill hole, and an inner diameter of 15 mm, which is consistent with the outer diameter of the grounding electrode. The length is 20 cm, and a copper wire with a diameter of 1.6 mm and a length of 3 cm is used as a metal wire.

[0045] The crushing modules are placed equidistantly on a plane 50 cm away from the edge of the rock, wherein the distance between the crushing modules is 40 cm, as shown in Figure 1 The shock wave propagates in the rock at the speed of sound, and for concrete, the speed of sound is 2300 m / s. The time for the shock wave to propagate to the free plane and reflect to the origin is calculated to be t 1=2 l / v =434.8μs, and the current oscillation period is calculated to be =177.7μs, which satisfies the principle of energy injection before the shock wave reflects back to the origin. After the plane crushing is completed, the plane becomes the new rock edge, and the crushing unit is placed in the next plane 50 cm away from the plane, and the crushing of the large volume of rock is carried out in stages.

[0046] The timing trigger unit is used to control the timing of energy release of the energy storage and pulse forming unit, so that the metal wire explosion of the electric explosion cylinder occurs in sequence to generate a shock wave, and the shock waves generated by adjacent electric explosion cylinders interfere and superimpose to improve the rock crushing effect.

[0047] Specifically, as shown in Figure 5 The timing trigger unit includes a photoelectric conversion unit, a timing adjustment unit and a power amplifier unit. The photoelectric conversion unit is used to convert the control optical signal transmitted by the optical fiber into an electrical signal. Using optical fiber for control signal transmission can effectively avoid strong electromagnetic interference in the pulse discharge process; the power amplifier unit uses a power amplifier to amplify the electrical signal after the timing adjustment unit delays to convert it into a trigger signal, which realizes the triggering of the thyristor. For trigger units 1 to n , from top to bottom, trigger Figure 1The thyristor switch is shown; the timing adjustment unit controls the conduction time of the thyristor switch, and specifically adopts FPGA to generate accurate delay trigger signal through timing operation. Let the trigger signal time of the power amplification unit 1 be 0, and the trigger time of the adjacent thyristor trigger should be =173.9μs, wherein the trigger time of the first n thyristor trigger switch is n- 1) t , and the interference superposition of the adjacent electric explosion cylinders is realized through the delay trigger, so that the rock breaking efficiency is improved.

[0048] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high-voltage pulse discharge rock-breaking device, characterized in that, include: The unit includes a charging unit, an energy storage and pulse current forming unit, a pulse current transmission unit, a breaking unit, and a timing triggering unit. The charging unit is used to convert low-voltage power frequency AC power into high-voltage DC power to provide the power required by the system. The energy storage and pulse current forming unit is used to store the electrical energy provided by the charging unit and to control the release of electrical energy through the timing triggering unit to form a pulse current; The pulse current transmission unit is used to transmit the pulse current generated by the energy storage and pulse current forming unit to the crushing unit; The timing triggering unit is used to control the energy release timing of the energy storage and pulse forming unit, control the shock wave generation time of the breaking unit, and realize the superposition of shock waves; The crushing unit uses the pulse current transmitted by the pulse current transmission unit to explode the metal wire, converting electrical energy into mechanical energy to crush the rock. Through staged crushing and time-sequenced discharge control, the shock waves of the crushing unit are superimposed to achieve the crushing of large-volume rocks. The crushing unit includes multiple crushing modules, and each crushing module includes a connecting unit, a discharge electrode, an electric explosion cylinder, and a drill bit. The borehole is generated by mechanical drilling. The discharge electrode and the electric explosion cylinder are placed inside the borehole. The connection unit connects the crushing module and the pulse current transmission module. The discharge electrode transmits the pulse current to the electric explosion cylinder. The electric explosion cylinder uses the pulse current to generate metal wire explosions to achieve rock crushing.

2. The high-voltage pulse discharge rock-breaking device as described in claim 1, characterized in that, The timing discharge control is achieved by controlling the detonation time of the metal wire in the electric explosion cylinder of the crushing module through the timing triggering unit. This ensures that when the shock wave generated by the electric explosion cylinder reaches the adjacent crushing module, it triggers the metal wire in the adjacent crushing module to detonate and generate a shock wave, thus achieving shock wave superposition. The trigger delay time of the adjacent crushing modules should meet the following requirements: in, d The distance between adjacent electric explosion cylinders, v The speed of sound in the rock.

3. The high-voltage pulse discharge rock-breaking device as described in claim 1, characterized in that, Each crushing module is placed at equal intervals on a surface parallel to the free surface of the rock. A staged crushing method is used, in which the rock between the crushed surface and the free surface is peeled off, and the crushed surface forms a new free surface, completing one stage of crushing. The next stage crushing unit is placed in the same manner.

4. The high-voltage pulse discharge rock-breaking device as described in claim 1, characterized in that, The discharge electrode has a coaxial structure and is reusable. The high-voltage electrode and the grounding electrode are filled with insulating material. The high-voltage electrode is made of tungsten-copper alloy, and the grounding electrode is made of a brass tube.

5. The high-voltage pulse discharge rock-breaking device as described in claim 1, characterized in that, The electric explosion cylinder includes a metal wire and a shock wave propagation cylinder. The metal wire explodes under pulsed current and forms a plasma channel. The channel expands and generates a shock wave. The shock wave propagation cylinder is made of insulating material and its outer diameter is consistent with the inner diameter of the borehole, transmitting the shock wave to the rock.

6. The high-voltage pulse discharge rock-breaking device as described in claim 1, characterized in that, The energy storage and pulse current forming unit includes multiple energy storage and pulse current forming modules; The energy storage and pulse current forming module includes an energy storage capacitor, a freewheeling silicon stack, a tuning inductor, and a thyristor switch. The energy storage capacitor stores the electrical energy input to the charging module. The thyristor switch is turned on by the timing trigger unit, releasing the stored energy in the energy storage capacitor to form a pulse current; the tuning inductor is used to adjust the amplitude and period of the output current; the freewheeling silicon stack prevents reverse voltage from appearing across the energy storage capacitor, which could damage the energy storage capacitor; the tuning inductor and the energy storage capacitor satisfy the following relationship: in, L The inductance value of the modulation inductor, C This refers to the capacitance value of the energy storage capacitor. l The distance from the broken electrode to the free surface. v The speed of sound in the rock.

7. The high-voltage pulse discharge rock-breaking device as described in claim 1, characterized in that, The pulse current transmission unit includes multiple pulse current transmission modules, and the pulse current transmission modules use coaxial cables, which have a multi-core wire structure.

8. The high-voltage pulse discharge rock-breaking device as described in claim 1, characterized in that, The timing triggering unit includes a photoelectric conversion unit, a timing adjustment unit, and a power amplification unit. The photoelectric conversion unit is used to convert the control optical signal transmitted through the optical fiber into an electrical signal. The power amplification unit is used to amplify the electrical signal and convert it into a trigger signal. The timing adjustment unit controls the conduction time of the thyristor switch and controls the explosion time of the electric explosion cylinder of the crushing unit to achieve the superposition of shock waves from adjacent crushing modules.

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