JP3381709B2 - Discharge probe - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a discharge probe for use in, for example, a rock crushing device for crushing rock using a plasma arc generated instantaneously. . [0002] For example, as one method of crushing rock, a hole formed in the rock is filled with a liquid, a discharge probe is inserted into the liquid, and a discharge is generated. It is known that the shock wave of an arc is transmitted to a rock to crush the rock. FIG. 3 shows a configuration of a rock crushing apparatus used in such a rock crushing method using a plasma arc. In FIG. 3, reference numeral 1 denotes a rock, 2 denotes a cylindrical hole formed in the rock, and 3 denotes a hole. Liquid such as water, 4 is a sealing material, 5 is a high voltage power supply, and 6 is a columnar discharge probe. A cylindrical hole 2 is formed at an appropriate place of the rock 1 to be crushed, and the hole 2
The discharge probe 6 is inserted into the center of the hole 3, the hole 2 is filled with the liquid 3, and the hole 2 is sealed with the sealing material 4. A discharge probe 6 has a thick insulator 6 around its outer periphery.
b, a high-voltage conductor 6 connected to the high-voltage side of the high-voltage power supply 5
a and a low-voltage conductor 6c connected to the low-voltage side of the high-voltage power supply 5 fixed to the outer peripheral surface of the insulator 6b. The insulator 6b has a tapered surface 6d at the end inserted into the hole 2. The ends of the high-voltage conductor 6a and the low-voltage conductor 6c protrude from the insulator 6b. When the voltage of the high-voltage power supply 5 is applied to both conductors 6a and 6c, a discharge 7 occurs between the high-voltage conductor 6a and the low-voltage conductor 6c along the tapered surface 6d of the insulator 6b at the end inserted into the hole 2.
Then, a plasma arc is generated by the discharge 7. At that time, a shock wave 8 due to the plasma arc is generated in the liquid 3, and the shock wave 8 acts on the surrounding rock 1, which is cracked and crushed. In the above-described discharge probe 6, since the discharge is caused to occur along the tapered surface 6d of the insulator 6b between the high-voltage conductor 6a and the low-voltage conductor 6c, damage to the insulator 6b may occur. Notably, there is no discharge stability (reproducibility)
In addition, there is a problem that the life of the discharge probe 6 itself is short, and it is necessary to replace the discharge probe 6 at several tens of times depending on the use conditions. The hole 2 is not located at the center of the hole 2 but is skewed to either side (discharge position cannot be adjusted to the center position), and its generation direction 8 is not along the axial direction of the hole 2; There is a problem that they do not work evenly and that the shock wave is dispersed in the axial direction of the hole 2 drilled in the rock, resulting in poor rock crushing efficiency. The present invention has been made in view of such a problem, and has as its object to provide a discharge probe having a stable discharge position and direction and a long life. According to the present invention, there is provided a discharge probe comprising: a first conductor having a discharge electrode at an end and an outer surface covered with an insulator; and a first conductor fixed to the outer surface of the insulator. And a discharge electrode, which is detachably held on the second conductor via a conductive metal fitting, and whose tip is disposed at a position facing the tip of the discharge electrode. Features. According to the present invention, one of the pair of discharge electrodes is provided at an end of a first conductor whose outer surface is covered with an insulator, and the other discharge electrode is formed of an insulating material formed on the first conductor. Since it is detachably held on the second conductor formed on the outer surface of the body by a conductive metal fitting, and the ends of both discharge electrodes face each other with an appropriate discharge gap therebetween, and are disposed in a fixed state. In use, the discharge position and direction are specified, there is no discharge along the surface of the insulator of the discharge probe, damage to the insulator can be prevented, and replacement of the other discharge electrode can be easily performed. Furthermore, when used as a discharge probe in a rock crushing apparatus, the discharge position and direction can be set by positioning the discharge position and direction in the axial direction at the center of the hole formed in the rock, and the shock wave of the plasma arc generated by the discharge can be set. Can be transmitted substantially perpendicularly and evenly to the peripheral wall of the hole to increase the efficiency of rock crushing, and the conductive bracket can be opened without resisting the shock wave, thereby preventing damage. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of a discharge probe according to an embodiment of the present invention in use, and FIG.
FIG. 2 is a sectional view showing the operation of the discharge probe of FIG. The same parts as those shown in FIG. 3 are denoted by the same reference numerals. In FIG. 1, reference numeral 10 denotes a discharge probe main body,
11 is one discharge electrode of the pair, 12 is the other discharge electrode, 13 is a high voltage conductor (first conductor) connected to the high voltage side of the high voltage power supply 5, 14 is an insulator, and 15 is a high voltage power supply 5 A low-voltage conductor (second conductor) connected to the low-voltage side, 16 is a conductive holding bracket, 17 is a conductive substrate, and 18 is a conductive mounting bracket. The discharge probe body 10 covers the outer peripheral surface of the high-voltage conductor 13 with a thick insulator 14, fixes the low-voltage conductor 15 on the outer peripheral surface of the insulator 14, and forms an engagement recess 16 a at the tip of the low-voltage conductor 15. The holding metal 16 is fixed, and the insulator 14 and the low-voltage conductor 15 are arranged concentrically with the high-voltage conductor 13 as a center. One discharge electrode 11 has a hemispherical tip at the tip, and is screwed to the tip of the high-voltage conductor 13 at the trailing end.
1a. The other discharge electrode 12 has a hemispherical tip at the tip, and is screwed to the tip of a projection 17 a formed at the center of the conductive substrate 17 at the rear end. The conductive substrate 17 is formed to have a slightly longer dimension than the diameter of the discharge probe body 10, and one end of a rod-shaped mounting member 18 is rotatably mounted at, for example, four end positions along the circumferential direction. I have. The other end of the mounting bracket 18 is bent inward, and the bent end 18 a removably engages with the engaging recess 16 a of the holding bracket 16. In use, as shown in FIG.
The bent end portion 18a is fitted into the engaging recess 16a of the holding fixture 16, and the other discharge electrode 12 is held by the discharge probe main body 10 to assemble the discharge probe. In the assembled discharge probe, the distal ends of the pair of discharge electrodes 11 and 12 are fixed to face each other in the central axis direction of the discharge probe main body 10 via a predetermined discharge gap. In this state, for example, the central axis of the discharge probe body 10 and the central axis of the hole 2 are inserted into a cylindrical hole 2 opened in the rock 1 and the hole 2 is filled with a liquid 3 such as water to seal the hole. Seal with material 4. When a voltage of the high-voltage power supply 5 is applied to one of the discharge electrodes 11 and the other discharge electrode 12, a discharge is generated between the tips of the two discharge electrodes 11 and 12, and a plasma arc is generated by the discharge. In this case, a discharge, that is, a plasma arc is generated on the central axis in the hole 2, and a shock wave is generated by the plasma arc in a direction perpendicular to the central axis, that is, in a direction perpendicular to the peripheral wall of the hole 2. Acts almost evenly on the surrounding wall, and the rock 1 is cracked and crushed. The shock wave also acts on the mounting bracket 18, but the rock 1 is crushed, and the bent end 18a of the mounting bracket 18 comes out of the engaging recess 16a of the holding bracket 16 as shown in FIG. , So that the impact of the shock wave 8 on the mounting bracket 18 is reduced. After rock crushing, the discharge probe main body 10 having the discharge electrode 11 and the mounting bracket 18 having the discharge electrode 12 are taken out and repeatedly used for the next rock crushing. When the discharge electrode is damaged by the discharge, each discharge electrode 1
Since screws 1 and 12 are screwed, the damaged discharge electrode is unscrewed and replaced. If an arc-resistant alloy material is used for the discharge electrode, the replacement frequency can be reduced. In the above description, rock grinding is taken as an example, but the discharge probe according to the present invention is not limited to rock grinding. The shape of the tip of the discharge electrode and the detachable attachment mechanism may be appropriate. As described in detail above, according to the present invention,
The discharge probe main body is hardly damaged, and the discharge stability and the service life of the discharge probe main body can be extended.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a configuration of a discharge probe according to an embodiment of the present invention in use. FIG. 2 is a sectional view showing the operation of the discharge probe of FIG. FIG. 3 is a cross-sectional view showing a configuration of a conventional discharge probe in use. [Description of Signs] 1 Rock 2 Hole drilled in rock 3 Liquid 4 Sealing material 5 High voltage power supply 7 Discharge (plasma arc) 8 Shock wave 10 Discharge probe main body 11 One discharge electrode 12 The other discharge electrode 13 High voltage conductor (first Conductor) 14 Insulator 15 Low-voltage conductor (second conductor) 16 Holder 16a Engagement recess 17 Conductive substrate 17a Projection 18 Mounting bracket 18a Bend end

Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) E21C 37/18 H05H 1/24

Claims (1)

(57) [Claim 1] A first conductor having a discharge electrode at an end and having an outer surface covered with an insulator, and a second conductor fixed to the outer surface of the insulator. A discharge electrode, which is detachably held on the second conductor via a conductive metal fitting and has a tip disposed at a position facing the tip of the discharge electrode.