JPH01500384A - induced plasma device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] induced plasma device Technical field TECHNICAL FIELD The present invention relates to electrolytic melting devices, and more particularly to induction plasma devices.

Background technology Currently, there are strict requirements for the quality of the metal produced, as well as for the equipment that performs the melting process. I have a request.

Induction melting equipment is increasingly being used in the foundry and metallurgical industries. But above The possibility of carrying out highly active metallurgical processes in this equipment depends on the temperature of the slag formed. (slag temperature becomes higher than molten metal temperature) (This reduces the strength of the physicochemical processes at the metal/slag interface.) composite For alloying (multi-component) @ and melting of alloys, use Flux with coating (protective) properties. It is necessary to use The output of the induction device, due to undesirable electrodynamic phenomena, In other words, because the meniscus is high and the molten metal circulates at high speed, the Limited by tolerance.

The above disadvantages are due to the combination of two heating methods, namely induction heating and plasma heating. This problem is eliminated in induced plasma equipment. Induction plasma equipment significantly reduces heating time to reduce the electrical energy required to produce per ton of metal, gas Improve the quality of metal products by reducing content, non-metallic inclusions, and harmful impurities active treatment of metals with rich slag; A raw material that can be used as a basic material for the production of pure metals by metallurgical methods that do not use charcoal. providing desirable conditions for remelting and reduction of ore-fuel pellets; Increasing the output of induction melting equipment by removing constraints on increases in specific rated output Can be done.

One known induction plasma device used for melting steel has an induction heating element. A pot, a bottom electrode that conducts current to the above steel, a plasma generator, and an induction heating element and and two independently controlled power supplies for the plasma generator. this Such a device is used, for example, in a collection of papers "Advanced procedures. ofMelting for 5naped Castings’, Kiev +1978. It is described in pp5 13.

This equipment uses two separate power supply sources, making it large and requiring a large factory floor area. occupies space, equipment costs are high and maintenance is complicated. Furthermore, the electric power during the melting process Since the utilization rate is relatively low, the power consumption of the entire device is large.

The disadvantages mentioned above are that the induction heating element and the plasma generator can be connected to one (common) power supply source. This problem is eliminated in induced plasma devices that supply power to the plasma.

Furthermore, one known induced plasma device (USSR Inventor's Certificate No. 462320) , “Discoveries, Inventions, Designs, and Trademarks,” 8th Edition, 1975) a vessel for melting the charge, connected to a tank and an alternating current power supply, and an induction heating at least one plasma generator electrically associated with the body and having a specific series connection therewith; comprising raw equipment.

However, in such equipment, the plasma arc depends on the melted state of the charge. In the event of an unexpected fire extinguishment or deenergization of a plasma generator, the The circuit is broken and the induction heating element is suddenly disconnected from the power supply, resulting in Excessive voltage applied to the capacitor bank will damage the capacitor bank.

Furthermore, it is not possible to separately control the operation of the induction heating element and the plasma generator. With this equipment, when the parameters of the melting charge suddenly change, the induction heating element It is not possible to reallocate power between the plasma generator and the plasma generator.

In the device described above, the plasma generator can only operate with alternating current. this This is advantageous in the final stages of melting and in the process of refining the molten metal. At the same time, it is dissolved To rapidly dissolve the well-shaped portion (well) in the charging material that is being , it is more advantageous in terms of energy consumption to operate the plasma generator with direct current. It is. Furthermore, in this device, the plasma generator and the induction heating element are connected to the same electric current. Since the flow is used, the operating mode of the former is strictly linked to the operating mode B of the latter. . The voltage that is applied to the plasma generator and determines its operating mode is the AC power supply. and the voltage applied to the induction heating element, and always exceeds this value. I can't get it. However, in some cases (e.g. when starting the main arc) (in some cases), it becomes necessary to increase this voltage, and the plasma generator needs to be increased. A need for separate activation also arises (for example when the induction heater is deenergized).

Disclosure of invention The purpose of the present invention is to prevent the induction heating element from being suddenly disconnected from an AC power source when extinguishing a plasma arc. The induction heating element and plasma generator are not separated during the melting process. An object of the present invention is to provide an induced plasma device in which power distribution can be reset.

This purpose, according to the invention, consists of a capacitor bank connected to an alternating current power source. A container for melting the charge, which is provided in the induction heating element, and an electric current connected to the induction heating element. an induced plasma comprising at least one plasma generating device in gaseous connection; In the apparatus, the plasma generator is connected in parallel with a portion of the winding of the induction heating body. This is achieved by an induced plasma device characterized by:

An induced plasma device is a group of plasma generators comprising two or more plasma generators. a plasma generating device, the group of plasma generating devices being connected to the portion of the winding of the induction heating body; It is desirable to connect in parallel with.

The induction plasma device includes the portion of the winding of the induction heating body and one plasma generator. or includes a switching element connected in series with a group of plasma generators. It is desirable that the

Induced plasma equipment is one plasma ordering equipment or one group of plasma generators. a rectifying device for the alternating current flowing through the induction heating element; A plasma generator may be electrically connected to the part of the winding, and the output of the device may be one plasma generator. or one group of plasma generators to form one plasma generator or one plasma generator. It is desirable to form a DC circuit for a group of plasma generators.

The induction plasma device includes the part of the winding of the induction heating body and one plasma generation device. or one group of plasma generators, and the alternating current rectifying device electrically. comprising associated additional switching elements, the additional switching elements comprising: One plasma generator or a group of plasma generators during the charge melting process. is connected to the output of the rectifier of alternating current, and is used for reheating process and/or smelting of molten metal. It is desirable to connect to the part of the winding of the induction heater during the process.

An induced plasma device is one plasma generator or a group of plasma generators. including a direct current power source connected in series with the alternating current rectifying device in the circuit of is advantageous.

The induced plasma device of the present invention comprises one plasma generator or a group of plasma generators. Plasma can be generated by connecting the generator in parallel with a portion of the winding of the induction heating element. To prevent an induction heating element from being suddenly disconnected from an AC power source when an arc is extinguished.

A part of the winding of the induction heating body and one plasma generator or one group of plasmas Since there is a switching element connected in series with the induction heating element and and power distribution to the plasma generator (e.g., the nature of the molten metal, the can be reset (depending on conditions), reducing heating time and saving electrical energy. The amount of electromagnetic stirring required for the molten metal is reduced, and the necessary electromagnetic stirring state is achieved for the molten metal at any input power. can be achieved, thereby making it possible to obtain alloys of various properties.

Furthermore, in an induced plasma device, one plasma generator or one group of plasma The Zuma generator can be operated with alternating current or direct current as appropriate. make this possible In order to directly or indirectly with one group of plasma generators or via additional switching elements. a rectifier connected to the rectifier.

Connecting the plasma generator to the output of the alternating current rectifier during the melting process of the charge The first part of the charge is rapidly melted into a "well" (the arc as a result of which the energy of the arc is effectively (high efficiently) is transferred to the charge, accelerating the melting process, resulting in undesirable heat losses, and ultimately Electrical energy consumption is reduced.

In the process of reheating and refining molten metal, a plasma generator or a group of plasma By connecting the generator to a portion of the winding of the induction heating element, it is possible to The slag formed on the surface of the molten metal can be heated more uniformly, and localized parts of the metal can be heated more uniformly. This can reduce excessive heating and melting loss of alloying elements. Plasma generator circuit Since a DC power supply is connected inside, an induction heating element and one plasma generator may be used. As a result of improving the suitability of the parameters of one group of plasma generators, the induction plasma The output of the Zuma device increases. Furthermore, the plasma generator can be used, for example, as a deenergized inductor. It can be operated separately from the heating element (independently from the induction heating element).

Brief description of the drawing In the following, the present invention will be described in further detail with reference to a specific implementation thereof, B, and in conjunction with the accompanying drawings. Explain in detail.

FIG. 1 shows an induction plasma apparatus (induction heating element and melting vessel length) according to the present invention. Figure 2 shows the two plasma generators and switching elements. a functional diagram of an induced plasma device according to the invention identical to FIG. 1, having Figure 3 is the same as Figure 1 with a rectifier for the alternating current flowing through the plasma generator. functional diagram of an induced plasma device according to the invention, FIG. 4 shows the same induction according to the invention as FIG. 3 with additional switching elements. The functional diagram of the plasma guiding device and FIG. Functional diagram of an induced plasma device according to the invention identical to FIG. 3 with a DC power supply It is.

BEST MODE FOR CARRYING OUT THE INVENTION In Figure 1, 1. The induced plasma device is connected to a capacitor bank 3 and an AC power source 4. It includes a container 1 for melting the charge, which is installed in an induction heating element 2 connected to the heating element 2. position setting at least one plasma generator capable of vertical movement by a mechanism (not shown); , is arranged in a cover 5 that closes the container 1. In this embodiment, this As a plasma generator, an electric arc plasma generator 6 is a part of the induction heating body 2. 7 is connected in parallel. Typically one plasma generator or one A group of plasma generators can be provided in the cover 5 or in the side wall of the container 1. can.

From the plasma generator 6 to the plasma arc 8 and the metal being melted 9 A bottom electrode 10 arranged at the bottom of the container 1 is used to close the operating current circuit. It will be done. Bottom electrode is water-cooled metal, graphite or cermet without water cooling made of material. The oscillator 11 connected to the electrode of the plasma generator 6 Thus, the viroft arc is started (ignited).

The electric circuit of the plasma generator 6 is composed of the following elements.

That is, a part 7 of the winding of the induction heating body 2 - the plasma generator 6 - the plasma arc 8-Metal being melted 9-Bottom electrode 10-Part 7 of winding of induction heating element 2 It is.

In another embodiment of the invention, the induced plasma device comprises the above-mentioned induced plasma It is almost the same as the device. The difference is that it has a second plasma generation bag W12 (Fig. 2). This reduces the operating current cycle of the plasma generator 6 (Fig. 2). The path is from the plasma arc 8 to the metal 9 and then to the plasma arc of the plasma generator 12. 13, so the bottom electrode 10 (FIG. 1) is not used.

In order to make the plasma generators 6, 12 in the optimum operating mode, the induced plasma device is Switch the number of windings of the induction heating element 2 connected in parallel with the plasma generator 6.12 This can be changed by means of a switching element 14 (FIG. 2). metal being melted 9 and the length of the plasma arc 8.13 changes during the melting process. Lasma generator 6, 12 parameters (e.g. current, voltage) and induction heating element Make changes in the number of windings above as necessary to match similar parameters in 2. cormorant. Due to the presence of the switching element 14, the power utilization coefficient of the AC power source 4 The electric current between the induction heating element 2 and the plasma generator 6.12 can be improved. The power distribution can be reconfigured and the technical system can be reconfigured.

In another embodiment of the present invention, the above-described induced plasma device and A plasma generator or group of plasmas that are similar but operate with direct current. A generator is used. The difference with the embodiment shown in FIG. 1 is that the induced plasma The apparatus includes a rectifier 15 (FIG. 3) for the alternating current flowing through the plasma generator 6. That's true. This rectifier has an input connected to a part 7 of the induction heating element 20 winding and an output is connected to the plasma generator 6 to form the following DC current circuit. i.e. , "negative" output of the alternating current rectifier 15 - plasma generator 6 - plasma arc 8 - Metal being melted 9 - Bottom electrode 10 - "Positive" of alternating current rectifier 15 ” output.

In order to be able to operate with both alternating current and direct current, this implementation B-like induction The plasma device comprises a switching element 16 (FIG. 4). switching element 16 is located at position I during the melting process of the charge and supplies the plasma generator 6 with an alternating current. during the process of reheating and/or refining the molten metal. Connect the plasma generator 6 to the part 7 of the winding of the induction heating element 2 at the position . . When in position H, the alternating current rectifier 15 is disconnected from the plasma generator 6. separated.

For example, in order to accelerate the melting process, the voltage of the plasma generator 6 can be changed to its power. Add energy to the molten metal using the plasma generation bag W6. If it is necessary to introduce an AC into the DC circuit of the plasma generator 6, The DC power supply 17 (Fig. 5) connected in series with the current rectifier 15 is connected to an inductive plasma. installed in the master device.

Next, the operation of the induced plasma device will be explained.

Container 1 (FIG. 1) is charged with the charge to be melted. Inviting plasma generator 6 It is connected in parallel with a portion 7 of the winding of the conductive heating element 2. Winding of part 7 of induction heating body 2 The number depends on the parameters of the plasma generator 6, induction heating element 2, and AC power supply. determined by experiment or calculation. Induction heating element/plasma generator system The total reactance is offset by the variable capacitor in capacitor bang 3. Ru. Turn on the AC power supply 4 and start heating the charge by the induction heating element 2. do. Turn on the oscillator 11 and put a pipe between the electrodes of the plasma generator 6. Generate lot arc. In this case, the plasma-forming gas is supplied to the plasma generator in advance. Introduce it into the storage 6. Next, between the cathode of the plasma generation bag W6 and the charged material, An arc 8 is generated and the melting process begins. To accelerate the dissolution process, inductive The heating element 2 and the plasma generator 6 should be operated simultaneously to start the melting process. It is. In this case, the high temperature of the plasma arc 8 causes fast melting of the charge and The electromagnetic field of the induction heating element 2 strongly stirs the metal 9 that is being melted to create a plasma. This prevents local excessive heating of the metal at the anode point of the arc 8.

Once the first part of the charge has melted down, switch off the plasma generating bag W6 and remove the charge. Charge the next portion of the container into container 1.

The charge charging process can also be carried out without turning off the plasma generation bag W6. Ru. Then close the vessel 1 again with the cover 5, the viroft arc and then the main arc. After generating 8, heating is continued to melt the entire charge.

Once the melting process is complete, the metal is reheated above its melting point and smelted if necessary. For this purpose, it is necessary to operate the induction heating element 2 and the plasma generator 6 together. , only the induction heating element 2 is operated. In either case, the molten metal is strongly electromagnetically stirred. Should be stirred.

Induction by energizing the plasma generation bag W6 (or extinguishing the plasma arc 8) The circuit of the heating element 2 is not broken and the induction heating element 2 operates normally! ! Continue.

The use of switching element 14 (FIG. 2) adds further possibilities. vinegar The switching element 12 determines the nature and requirements of the metal being melted before melting. Depending on the required melting conditions, the required number of windings of the induction heating body 2 are connected to the plasma generator 6°. 12 can be connected. This number of turns does not need to be changed during the melting process. . However, due to the presence of switching element 14, plasma is generated during the melting process. When the length of the arc 8.13 and the properties of the metal change, the winding occurs during the melting process. By changing the number of wires, the induction heating body 2 and the plasma generation bag ff6.12 The operating mode of the system can be optimized. thereby maximizing efficiency and Energy consumption can be minimized. In other cases, the The induced plasma device operates in the same manner as described above.

The induced plasma device shown in Figure 3 operates in the same way, except that the plasma generator is The difference is that it operates at

As is known, a DC arc has a well-defined directional cone shape, and It has a certain “elasticity and stiffness” so that it can be quickly penetrated through deep “wells” in the charge. can be burned. Therefore, in this embodiment, plasma generation All the energy introduced from bag W6 can be used for heating the charge; Moreover, the wall of the melting vessel 1 is shielded from the influence of the plasma arc 8 by the charge. be able to. This significantly increases the life of the lining.

However, during the reheating and refining of molten metal, the direct current arc Contributes to saturation and deteriorates metal quality.

Furthermore, during this period, the walls of the melting vessel are directly affected by the plasma arc. , the radiation of a direct current arc is much stronger than that of an alternating current arc, so the lining Significantly shortens lifespan. If the plasma generator is operated with alternating current during the melting period, Less effective. That is, the shape of the alternating current plasma arc is unclear, and the shape of the metal is Although the "surface" is heated, combustion in the deep "wells" in the charge does not occur, so the This is because the energy is not utilized very effectively by the charge.

Therefore, during the period of reheating and refining of the molten metal, the plasma of the induced plasma device By operating the arc generator 6 with alternating current, slag is additionally and effectively added to the alternating current arc 8. It is desirable to heat the container 1 so that the slag coats the lining of the container 1.

As a result, the saturation of the metal by the gas is reduced and the quality of the metal 9 is improved. However, Therefore, during the melting process of the charge, the switching element 16 (FIG. 4) is set in position I. By doing so, the plasma generator 6 is operated with direct current, and the metal 9 is reheated and During the refining period, plasma is removed by setting the switching element 16 to position ■. A magnetic generator 6 is connected directly to a portion 7 of the winding of the induction heating body 2 . switching With element 16 set in this position, the molten metal is reheated to the required temperature, and Perform refinement if necessary (of course, other technical operations are also possible) ). Smelting involves the formation of an active slag on the metal surface or the addition of suitable alloying elements or This is done by introducing refining elements into the molten metal.

The AC arc 8 heats the slag to a high temperature, and this high temperature causes the metal/slag system to By promoting the progress of the physical and chemical process, the induction heating element 2 also heats the molten metal 9. Stir vigorously to evenly distribute the elements introduced into the metal over the entire volume of container 1. uniform distribution and removal of reaction products from the melt to allow slag-off. This allows the metal refining process to be carried out under optimal conditions.

The induced plasma device shown in Figure 5 is constructed in the same way as the induced plasma device described above. move. However, the operating mode of the plasma generator 6 may be changed depending on the circuit of the plasma generator 6. by the switching element 14 taking into account the presence of an additional DC power supply 17 in the I choose.

The voltage applied to the plasma generator 6 is applied to the alternating current rectifier 15 and the additional The voltage of the DC power supply 17 is used to set the voltage of the U1Σ plasma generator 6, respectively. , equal to U by the switching element 14 and the alternating current rectifier 15 A voltage is applied to the plasma generator 6.

Plasma generator 6 necessary to respond to changes in the properties of molten metal 9 during the melting process The actuation B-like modification of adjusts the value of the voltage 'a, by the switching element 14 This can be done by

The main device 6 is selected to be able to operate in an autonomous manner. Thereby, plasma The selection of the required operating mode of the generator 6 is facilitated, reducing energy consumption and technical capabilities. The adaptability of the induced plasma device from the viewpoint of For example, plasma When the heating device 6 operates in an autonomous manner, the required metal circulation rate is and at the same time, the function of metal heating can be achieved with plasma generation bag W6 Ru.

Industrial applicability The induced plasma device of the present invention is suitable for high quality ferrous and non-ferrous metals in metallurgical and foundry industries. Suitable for melting and processing iron alloys.

Procedural amendment (formality) November 10, 1986 Yoshi, Commissioner of the Patent Office 1) Takeshi Moon 1.Display of the incident PCT/SU8610 OO4B 2. Name of the invention induced plasma device 3. Person who makes corrections Relationship to the incident: Patent applicant 4. Agent Address: 8-10-6 Toranomon-chome, Minato-ku, Tokyo 105, subject to amendment (1) Translation of the specification (2) Translation of the scope of claims 7. Contents of correction (1) An engraving of the translation of the specification (no change in content) (2) An engraving of the translation of the scope of the claims (No change in content) 8. List of attached documents (1) Translation of the specification: 1 copy (2) One translation of the scope of claims

Claims (6)

[Claims] 1. An induction heating element ( 2), a container (1) for melting the charge, and the induction heating element (2). ) comprising at least one plasma generator (6) electrically connected to In the induction plasma device, the plasma generator (6) is connected to the induction heating body (2). Induced plasma device, characterized in that it is connected in parallel with a part (7) of the winding . 2. A group of plasma generators comprising two or more plasma generators (6, 12) This one group of plasma generators (6, 12) is used to heat the induction heating element (2). according to claim 1, characterized in that it is connected in parallel with said part (7) of the winding. Induced plasma device. 3. the part (7) of the winding of the induction heating body (2) and one plasma generator (6); ) or a switch connected in series with a group of plasma generators (6, 12) 3. Inductive pulley according to claim 1 or 2, characterized in that it comprises a guiding element (14). Lasma device. 4. One plasma generator (6) or one group of plasma generators (6, 12 ), the rectifying device (15) for alternating current flowing through the rectifying device (15), A force is electrically associated with the portion (7) of the winding of the induction heating element and A plasma generator with one output (6) or a group of plasma generators (6,1 2) combined with one plasma generator (6) or one group of plasma generators Claim 1 or 2 or 2, characterized in that it forms a direct current circuit of the device (6, 12). is the induced plasma device described in 3. 5. the part (7) of the winding of the induction heating body (2) and one plasma generator ( 6) or a group of plasma generators (6, 12) and said rectification of alternating current; comprising an additional switching element (16) electrically associated with the device (15). , the additional switching element (16) comprises one plasma generator (6) or A group of plasma generators (6, 12) is connected to the AC current during the charge melting process. Connected to the output of the flow device (15), during the reheating process and/or the molten metal refining process. Claim characterized in that it is connected to the part (7) of the winding of the induction heating body (2). 4. The induced plasma device according to 4. 6. One plasma generator (6) or one group of plasma generators (6, 12 ) includes a DC power source connected in series with the alternating current rectifier (15). The induced plasma device according to claim 4, characterized in that it comprises: