JPH04262398A - Arc moving type heat plasma jet generating device - Google Patents

Abstract

PURPOSE:To move arc discharge in stable state by changing the inter-electrode distance through repetition of inclining a discharge electrode, inserting a plate in the flow path for a thermo-medium, and moving it periodically in the longitudinal direction of electrodes. CONSTITUTION:When current is fed from a power supply 10 to electrodes 1, 2, an arc current is generated between the electrodes, and heat plasma is produced in a thermo-medium gas flowing in the space between them 1, 2. Thus a plasma jet is obtained. When current is fed to either of the piezo elements 4 and the electrode 2 is inclined relative to the other 1, the electric field is inclined to cause the arc current to move toward the intense side of electric field. An insert plate 7 is installed on the way of an influx hole 9 for the thermo-medium gas to constitute a baffle plate, and thereby a low pressure part is generated locally in the space between the electrodes 1, 2, so that the arc current moves in the direction of generating stable state of electric discharging. Current feed to piezo element 4 is repeated periodically, and the electrode 2 is swung relative to the other 1, and interlockingly the insert plate 7 is moved periodically. At this time, the arc current becomes equivalent to the plane arc state at the electrodes 1, 2, and the thermo-medium gas is heated to cause emission of a plane plasma jet.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc-moving thermal plasma jet generator, which can be applied as a heating device for steel materials and steel plates, a welding device, a cutting device, and a thermal spraying device.

0002

2. Description of the Related Art FIG. 3 shows an example of the configuration of a conventional linear thermal plasma generator. As shown in the figure, an arc discharge 8 is generated between the opposing linear cathode 1 and anode 2, and the discharge position is moved by a water cooling coil 9 using an alternating magnetic field in the plasma gas ejection direction. A steady magnetic field in the direction of the arc current by the coil 10 was used to stabilize the discharge.

0003

A conventional planar thermal plasma jet generator utilizes an external magnetic field from an electromagnetic coil to move the arc discharge position and stabilize the arc discharge. However, it is difficult to determine the appropriate value of the magnetic field, and as a result, arc discharge becomes unstable as the arc discharge position moves, resulting in termination of arc discharge. The present invention has been made in view of the above-mentioned prior art,
Arc discharge is generated between opposing electrodes, and the discharge position is changed periodically by repeatedly tilting the discharge electrodes or by placing an insertion plate that moves in the longitudinal direction of the electrodes in the heat medium flow path. It is an object of the present invention to provide an arc-moving thermal plasma jet generating device that can generate an arc-moving thermal plasma jet.

0004

[Means for Solving the Problems] A first configuration of the present invention that achieves the above object generates an arc discharge between a pair of long discharge electrodes arranged oppositely, and causes arc discharge to flow between the discharge electrodes. An arc-type thermal plasma generator that generates a plasma jet by generating thermal plasma in a heating medium, comprising means for periodically swinging at least one of the pair of elongated discharge electrodes within an opposing plane. It is characterized by A second configuration of the present invention that achieves the above object is to generate an arc discharge between a pair of elongated discharge electrodes disposed facing each other, and to generate thermal plasma in a heat medium flowing between the discharge electrodes. An arc-type thermal plasma generator for generating a plasma jet, characterized in that an insertion plate movable periodically in the longitudinal direction of the discharge electrode is disposed in the flow path of the heat medium and upstream of the discharge electrode. shall be. A third configuration of the present invention that achieves the above object is to generate an arc discharge between a pair of long discharge electrodes disposed facing each other, and to generate thermal plasma in a heat medium flowing between the discharge electrodes. In an arc-type thermal plasma generation device that generates a plasma jet, means for periodically swinging at least one of the pair of elongated discharge electrodes within opposing planes; The present invention is characterized in that an insertion plate movable periodically in the longitudinal direction of the discharge electrode is arranged on the upstream side of the electrode.

[0005]

[Operation] By tilting the discharge electrodes, the arc discharge generated between the opposing discharge electrodes is moved to a position where the electric field is higher by reducing the distance between the electrodes. In addition, arc discharge occurs when the pressure and electrode spacing are sufficiently large in a localized low-pressure area obtained by inserting an insertion plate that causes pressure loss in the middle of the inlet of the heating medium gas, and the pressure or electrode spacing decreases. According to Paschen's law, which states that the discharge starting voltage decreases in the direction of downsizing, the discharge stabilizes in the direction of lower pressure. By continuously controlling the electrode spacing in conjunction with the interelectrode pressure, a planar arc plasma jet can be obtained from between straight or curved electrodes.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments shown in the drawings. An embodiment of the present invention is shown in FIGS. 1(a) and 1(b). As shown in the figure, a pair of elongated discharge electrodes 1 and 2 are arranged facing each other, and these electrodes 1 and 2 are
are connected to the power source 10 and function as an anode and a cathode, respectively. A flow path 6 through which cooling water passes passes through the inside of the discharge electrodes 1 and 2, and the opposing surfaces thereof have a substantially semicircular curved shape. The surfaces of the electrodes 1 and 2 may be planar. The side walls and rear walls of both electrodes 1 and 2 are
The discharge electrode 1 is insulated by a heat-resistant insulator 3 and supported via the insulator 3. On the other hand, the discharge electrode 2 is supported on both sides by a piezoelectric element 4 and a spring 5, respectively, so that it can be tilted with respect to the discharge electrode 1. Most of the load of the electrode 2 is supported by the spring 5. Therefore,
The discharge electrode 2 is inclined with respect to the discharge electrode 1 by applying current to one of the piezoelectric elements 4 and causing it to expand and contract. discharge electrode 1,
The narrower the distance between the electrodes 2, the higher the electric field, so if the discharge electrode 2 is tilted with respect to the discharge electrode 1, the electric field will be tilted between them.

On the other hand, an inlet 9 is provided between the discharge electrodes 1 and 2 for introducing heat medium gas. In the middle of this inlet 9, an insertion plate 7 is arranged to locally lower the pressure. This insertion plate 7 is movable along the longitudinal direction of the discharge electrodes 1 and 2 from the outside by a mechanism not shown. The insertion plate 7 has the same function as a so-called baffle plate.

In this embodiment having the above configuration, the power supply 10
By applying current to the discharge electrodes 1 and 2 from the
, 2, a thermal plasma is generated in the heating medium gas flowing between the discharge electrodes 1 and 2, and a plasma jet is obtained. Furthermore, when one of the piezoelectric elements 4 is energized to tilt the discharge electrode 2 with respect to the discharge electrode 1, the electric field is tilted between them. Therefore, the arc current 8 generated between the discharge electrodes 1 and 2 moves toward the higher electric field strength. Furthermore, since the insertion plate 7 locally generates a low pressure area between the discharge electrodes 1 and 2, the arc current 8 moves in the direction of stable discharge according to Paschen's law.

Here, by periodically repeating energization to the piezoelectric element 4 at a frequency of several tens to several hundreds of Hz, the discharge electrode 1
When the discharge electrode 2 is periodically oscillated in a plane facing the electrodes 2 and the insertion plate 7 is moved periodically in conjunction with this movement, the arc current 8 is generated entirely between the electrodes 1 and 2. This is equivalent to a planar arc state that spreads out, heating the heat transfer gas and ejecting a planar plasma jet. In this way, when the arc discharge is moved by energizing the piezoelectric element 4 and moving the insertion plate 7, an external magnetic field by the electromagnetic coil becomes unnecessary. Therefore, the conventional problem of difficulty in obtaining an appropriate magnetic field is solved, and it becomes possible to move the arc discharge in a stable state.

[0010] In this embodiment, the power supply to the piezoelectric element 4 and the movement of the insertion plate 7 were used together, but even if either one
Arc current can be moved. Therefore, by periodically repeating the power supply to the piezoelectric element 4 or the movement of the insertion plate 7, it is possible to make it equivalent to a planar arc and emit a planar plasma jet. In addition, the discharge electrode 2
The means for oscillating is not limited to the piezoelectric element 4,
Other driving sources may also be used. Furthermore, the spacing between the electrodes,
The length of the electrode, the pressure and flow rate of the heating medium are not particularly limited.

[0011]

Effects of the Invention As described above in detail based on the embodiments, the present invention provides for periodically swinging at least one of the discharge electrodes within the opposing planes, or moving the discharge electrodes in the longitudinal direction. By inserting and periodically moving the insertion plate, the arc discharge can be made to move repeatedly in the longitudinal direction of the discharge electrode, making it equivalent to a planar arc, thereby making it possible to emit a planar plasma jet. can. Therefore, in order to move the arc discharge, an external magnetic field by the electromagnetic coil is not required, and it becomes possible to move the arc discharge in a stable state.

[Brief Description of the Drawings] [Fig. 1] An arc moving thermal plasma jet according to an embodiment of the present invention; Fig. 1(a) is a cross-sectional view thereof, and Fig. 1(b)
is its front view. FIG. 2 is an explanatory diagram showing the operation of an embodiment of the present invention;
Figure (a) shows how the arc current moves due to the inclination of the discharge electrode, and figure (b) shows how the arc discharge moves due to the movement of the insertion plate. FIG. 3 is a configuration diagram of a conventional linear thermal plasma jet generator. [Explanation of symbols] 1 Discharge electrode (anode) 2 Discharge electrode (cathode) 3 Insulator 4 Piezoelectric element 5 Spring 6 Cooling water channel 7 Insertion plate 8 Arc current 9 Heat medium gas inlet 10 Power supply

Claims (3)

[Claims] 1. An arc-type heating device that generates an arc discharge between a pair of long discharge electrodes arranged opposite each other, generates thermal plasma in a heat medium flowing between the discharge electrodes, and generates a plasma jet. 1. An arc-moving thermal plasma jet generating device, characterized in that the plasma generating device comprises means for periodically swinging at least one of the pair of elongated discharge electrodes within opposing planes. 2. An arc-type heating device that generates an arc discharge between a pair of long discharge electrodes arranged facing each other, generates thermal plasma in a heat medium flowing between the discharge electrodes, and generates a plasma jet. In the plasma generating device, an arc-moving thermal plasma jet characterized in that an insertion plate movable periodically in the longitudinal direction of the discharge electrode is disposed in the flow path of the heat medium and upstream of the discharge electrode. Generator. 3. An arc-type heating device in which an arc discharge is generated between a pair of long discharge electrodes arranged facing each other, and thermal plasma is generated in a heat medium flowing between the discharge electrodes to generate a plasma jet. In the plasma generation device, means for periodically swinging at least one of the pair of elongated discharge electrodes within opposing planes, and a means for periodically swinging at least one of the pair of elongated discharge electrodes within opposing planes; An arc-moving thermal plasma jet generator characterized by having an insertion plate that is periodically movable in the longitudinal direction of the plasma jet generator.