KR20040107334A - Microwave plasma torch for cutting, welding, and local -heating - Google Patents

Abstract

PURPOSE: A microwave plasma torch for cutting, welding and partially heating metal is provided to generate high temperature plasma through a nozzle of a waveguide by focusing microwave with a microwave oscillator and inducing the powerful electric field. CONSTITUTION: A plasma nozzle(12) is made of high conductivity, heat resistance and abrasion resistance material, and installed to a waveguide(18a). Plasma gas is injected into a gas injection hole(16) of a holder(40), and ejected via a plasma nozzle tip(8). The plasma nozzle tip is protruded in the waveguide, and a circular hole(10) is formed concentrically with the plasma nozzle in a lower part(29) of the waveguide. Microwave is generated from a magnetron(22), and transmitted through the tapered waveguide. The powerful electromagnetic field is formed between the plasma nozzle tip and a ring(14) of the circular hole, and high temperature and high speed plasma(6) is generated by ionizing plasma gas.

Description

Electromagnetic Plasma Torch for Cutting, Welding and Local Heating Devices {MICROWAVE PLASMA TORCH FOR CUTTING, WELDING, AND LOCAL -HEATING}

The present invention relates to a metal cutting, welding, and local heating apparatus using a jet plasma that generates a high temperature of thousands of degrees or more, and more particularly, to generate microwaves using a conventional 2.45 kW electromagnetic wave oscillator, and easily and economically. The present invention relates to an apparatus for generating a high temperature plasma and cutting, welding and locally heating a metal using a high temperature thermal plasma of several hundred micrometers to several tens of millimeters in diameter depending on the plasma nozzle.

In general, a plasma cutting machine generates an electric arc between an electrode and a base metal, and when air is injected through the nozzle through the nozzle, the air is ionized while passing through the arc airflow, thereby cutting the base metal while forming a high-speed, high-temperature jet plasma.

There are a variety of plasma torches, such as direct current arc torches, inductively coupled plasma torches and capacitively coupled high frequency torches, which provide conventional high temperature heat sources. DC arc torch directly applies electric field between two electrodes, so it is troublesome to replace electrode and uses high current of more than hundreds of amperes. Therefore, expensive current supply device requires high power consumption and operation cost. In addition, there is a problem that the energy efficiency of the inductively coupled plasma torch and the capacitively coupled high frequency plasma torch is very low to less than 40%.

As a result, such a conventional plasma torch has a high generation cost of plasma and many additional facilities.

Korean Patent No. 0375423, registered on February 26, 2003, was devised by HONG of the present inventors and relates to an apparatus for removing smoke emitted from a diesel engine using an electromagnetic plasma torch of 5000 to 6000 degrees Celsius. . According to this invention, an electromagnetic plasma torch is used to oxidize and remove soot by contacting the electromagnetic plasma with soot discharged from a diesel engine. The electromagnetic plasma torch uses an inner diameter of 22 to 30 mm in the discharge tube, and as in the present invention, it is difficult to centralize the plasma in a high temperature region to a few hundred μm in diameter and to concentrate it on the base material to be cut and locally heated.

The present invention is a combination of the advantages of the above-described Korean patent of Hong (HONG) while overcoming the above-described disadvantages by using a conventional electromagnetic wave oscillator to focus the microwave at a specific location to induce a very strong electric field through Its purpose is to provide a high temperature electromagnetic plasma torch to provide cutting, welding and local heating devices.

1 is a longitudinal cross-sectional view illustrating the present invention;

FIG. 2 is a cross sectional view of a portion indicated by reference numeral 80 in FIG. 1, FIG.

Figure 3 is a longitudinal sectional view showing another example of the present invention,

4 is a bottom view showing an example of the plurality of electromagnetic plasma torch arrangement of FIG.

5 is a plasma flame photograph of the present invention.

In order to achieve the above object, the present invention provides a magnetron (22) for oscillating a typical 2.45 GHz electromagnetic wave; A power supply system (24) installed to supply power to the magnetron (22) by adding a high voltage capacitor and a high voltage diode to a conventional three-phase rectifier or a conventional half-wave voltage multiplier; A waveguide (18) for transmitting the electromagnetic waves supplied from the magnetron (22) to supply energy for discharge; When the wavelength in the waveguide (18) is lambda _g , a hole (10) is provided in the lower end of the waveguide (18) at a position that becomes lambda _g / 4 from the waveguide end (20); A plasma nozzle 12 installed through the lower waveguide hole 10 at an upper end where electromagnetic wave energy transmitted from the waveguide 18 is concentrated; Allowing the plasma gas to pass through the plasma gas inlet (16) into the plasma nozzle (12); Jet-type high-temperature plasma 6 is generated by discharging the plasma gas at the plasma nozzle tip 8 by a strong electric field between the hole 10 provided at the lower end of the waveguide 18 and the plasma nozzle tip 8. An electromagnetic plasma torch (100); The base material 50 to be cut, welded, or locally heated is processed by the electromagnetic plasma torch while being moved up, down, left, and right at a constant speed by a conventional conveyor system 54. Will be provided.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

According to one embodiment of the invention, the waveguide 18 is divided into a microwave head waveguide 18b and a reactor waveguide 18a, as shown in FIG. It is connected. The magnetron 22, which supplies microwaves to the waveguide 18b, is a 2.45 GHz electromagnetic wave oscillator commonly used in a microwave oven and is powered by a power supply system 24 composed of a three-phase rectifier or a full-wave voltage multiplier. Overheating is prevented by the device 26 and the chiller is constructed by conventional techniques such as cooling fans.

Plasma nozzle 12, which is provided at a position λ _g / 4 away from the end 20 of the waveguide 18, is connected to the holder 40 having the gas inlet 16, and is connected to the holder 40. The plasma nozzles 12 are connected together with female and male threads so as to be separated from each other. The plasma nozzle 12 is installed through the upper end 29 at the lower end 19 of the waveguide 18a, and the plasma nozzle 12 can be guided to the upper end 29 of the waveguide 18a. A central hole 10 as in 12 is provided in the upper end 29 of the waveguide 18a. The ring 14 provided in the hole 10 of the upper end 29 of the waveguide 18a is generated by an arc between the tip 8 of the plasma nozzle and the ring 14 when impedance matching is not made. Attached separately to prevent damage to the waveguide 18a, the ring 14 is composed of a conductor having good wear resistance and heat resistance. The holder 40 is connected to a cooling jacket 42 attached to the upper end 19 of the waveguide 18a. The cooling jacket 42 includes a cooling water inlet 30 and an outlet 32. 40) and detachable. The plasma nozzle 12 made of tungsten, stainless steel, brass, or the like is adapted to be able to adjust the height from the lower end 29 of the waveguide 18a by the holder 40 and at the same time the waveguide 18a of the holder 40. The impedance penetration can be induced by adjusting the space penetration depth between the upper end 19 and the lower end 29. Depending on the application, the inner diameter of the plasma nozzle 12 can vary from several hundred μm to several tens of mm.

The microwaves oscillated from the magnetron 22 are transmitted through the waveguide 18 and the plasma gas injected from the plasma gas inlet 16 is ionized by a strong electric field between the tip 8 of the plasma nozzle and the ring 14. A high temperature, high velocity jet plasma 6 is generated to produce an electromagnetic plasma torch 100.

The base material 50 mounted on the spacer 52 with a conventional conveyor system 54 that can move the distance from the jet-type plasma 6 torch to the adjustable up, down, left, and right sides is cut by the jet-type plasma 6 torch, Welding and local heating

FIG. 2 is a cross-sectional view of the portion indicated by reference numeral 80 of FIG. 1, wherein the 2.45 kHz microwave 60 transmitted through waveguide 18 is connected to the lower end of waveguide 18a by electromagnetic inductive coupling with plasma nozzle 12. A strong electric field between the ring 14 of 29 and the plasma nozzle tip 8 ionizes the plasma gas ejected through the plasma nozzle hole 4 to generate a jet plasma torch.

3 is a longitudinal cross-sectional view of an apparatus for cutting, welding, and local heating of a plurality of base materials at the same time by connecting a plurality of electromagnetic plasma torch 100. The plurality of electromagnetic plasma torches 100 are connected and assembled by the package box 90, and plasma jets are ejected into the package box holes 92. The plasma gas supply device 36 supplies a plasma gas to each of the plurality of plasma torches 100. By using a plurality of electromagnetic plasma torch, at the same time a large number of the base material 50 can be cut and localized at regular intervals, a large amount of the base material 50 can be welded.

4 is a bottom view illustrating an example of a plurality of electromagnetic plasma torch arrays of FIG. 3. Through holes 92 of the package box 90, portions indicated by reference numeral 110 are shown in FIGS. 3 and 4. In addition, by arranging the plurality of electromagnetic plasma torch 100 in a circular shape, one base material 50 may be heated at a uniform and fast time.

5 is a plasma flame photograph generated using the electromagnetic plasma torch 100. At this time, argon gas was injected, the applied microwave power was 300 watts, and the inner diameter of the nozzle was 1.5 mm.

Experimental Example

It was confirmed that plasma can be easily generated by using gases such as nitrogen, air, and argon using a magnetron capacity of 900 W. The size of the nozzle was changed from 1 mm outer diameter, 0.5 mm inner diameter to 10 mm outer diameter, and 6 mm inner diameter and outer diameter, and as a result of experiments, plasma was easily generated at all nozzle sizes. Plasma nozzle outer diameter 4 mm The long plasma flame of about 20 cm was observed in 1 mm of inner diameter, 900 W of microwave power, and 1 liter of argon gas.

In a 300 W-powered argon plasma, a quartz tube with an outer diameter of 8 mm and an inner diameter of 5.5 mm was melted while rotating, and a 150 μm-thick quartz fiber was extracted, and a 2 mm thick carbon steel was cut from an 600 W argon plasma with an electromagnetic plasma torch. And made holes of various sizes.

The present invention can generate a plasma easily and economically through a nozzle installed at a specific position of the plate by oscillating the microwave using a conventional 2.45 GHz electromagnetic wave oscillator, the structure is simple, the price is low, and the high temperature It is possible to generate a high-speed plasma jet, thereby obtaining an effect that can be used for cutting, welding, and local heating of the base material. In addition, the plurality of electromagnetic plasma torch can be rearranged and newly changed, and at the same time, the effect of cutting, welding, and local heating of many base materials can be obtained.

Claims (10)

In a device where electromagnetic energy induces an electric field and uses the electric field to make a plasma torch, When the wavelength in the waveguide 18 is λ _g , the plasma nozzle 12 having a cylindrical shape at a position λ _g / 4 away from the waveguide terminal 20 and having excellent electrical conductivity, heat resistance, and abrasion resistance is a waveguide ( Installed through 18a); Plasma gas is injected through the gas inlet 16 of the holder 40 and ejected through the plasma nozzle tip 8; The lower end 29 of the waveguide 18a from which the tip 8 of the plasma nozzle is drawn is provided with a circular hole 10 in the same center as the plasma nozzle 12; The microwave 60 oscillated in the magnetron 22 is transmitted through the tapered waveguide 18 to form a strong electric field between the plasma nozzle tip 8 and the ring 14 installed in the circular hole 10. An electromagnetic plasma torch in which a plasma gas is ionized to generate a high-temperature, high-speed jet plasma (6). The method of claim 1, Electromagnetic plasma cutting machine and local heating apparatus consisting of a conveyor system 54 moving up, down, left and right so that the base material 50 is exposed to the ejected plasma torch. The method of claim 1, One end of the plasma nozzle 12 is coupled to a detachable, adjustable insertion depth holder 40 installed in the waveguide 18a described above; Electromagnetic plasma torch which adjusts the depth of the holder (40) into the waveguide (18a) and at the same time the distance between the plasma nozzle 12 and the lower end (29) of the waveguide (18a) for impedance matching. The method of claim 1, Using an inexpensive magnetron 22 operating at an operating frequency of 2.45 kHz with a power range of 0.6 kV to 1.4 kW, an atmospheric plasma is produced using at least a few hundred milliliters up to several tens of liters of plasma gas 16 and a reaction gas. Electromagnetic Plasma Torch. The method of claim 1, Apparatus comprising a plurality of electromagnetic plasma torch (100). The method of claim 1, An electromagnetic plasma torch having a size of a hole 4 of a plasma nozzle tip through which a gas is injected through the plasma nozzle 12 from several hundreds of micrometers to several tens of mm. The method of claim 1, An electromagnetic plasma torch consisting of a tapered nozzle tip for generating a strong electric field in the plasma nozzle tip (8). The method of claim 1, Electromagnetic plasma torch provided that the installation direction of the plasma nozzle 12 is perpendicular to the transmission direction of the microwave 60. The method of claim 5, An electromagnetic plasma torch wherein the plasma nozzle 12 is a tungsten nozzle. The method of claim 1, An electromagnetic wave plasma torch having a ring (14) made of a conductor having excellent electrical conductivity, heat resistance, and abrasion resistance in a hole (10) on the same center as the plasma nozzle (12) at the lower end (29) of the waveguide (18a).