Melting metal at home in an induction electric furnace. how to make a metal melting furnace how to make an induction metal melting furnace

Induction heaters work on the principle of “getting current from magnetism”. In a special coil, a high-power alternating magnetic field is generated, which generates eddy electric currents in a closed conductor.

A closed conductor in induction cookers is metal utensils, which are heated by eddy electric currents. In general, the principle of operation of such devices is not complicated, and with little knowledge in physics and electrical engineering, it will not be difficult to assemble an induction heater with your own hands.

The following devices can be made independently:

1. Devices for heating in a heating boiler.
2. Mini ovens for melting metals.
3. Plates for cooking food.

Do-it-yourself induction cooker must be made in compliance with all norms and rules for the operation of these devices. If electromagnetic radiation dangerous for humans is emitted outside the case in the lateral directions, then it is strictly forbidden to use such a device.

In addition, a great difficulty in the design of the stove lies in the selection of material for the base of the hob, which must meet the following requirements:

1. Ideal for conducting electromagnetic radiation.
2. Not conductive.
3. Withstand high temperature stress.

In domestic induction hobs, expensive ceramics are used, when made at home induction cooker, to find a worthy alternative to such material is quite difficult. Therefore, to begin with, you should design something simpler, for example, an induction furnace for hardening metals.

Manufacturing instructions

Blueprints

For the manufacture of the furnace you will need the following materials and tools:

• solder;
• textolite board.
• mini drill.
• radioelements.
• thermal paste.
• chemical reagents for board etching.

Additional materials and their features:

1. To make a coil, which will emit an alternating magnetic field necessary for heating, it is necessary to prepare a piece of copper tube with a diameter of 8 mm and a length of 800 mm.
2. Powerful power transistors are the most expensive part of a homemade induction installation. To mount the frequency generator circuit, it is necessary to prepare 2 such elements. For these purposes, transistors of brands are suitable: IRFP-150; IRFP-260; IRFP-460. In the manufacture of the circuit, 2 identical of the listed field-effect transistors are used.
3. For the manufacture of an oscillatory circuit you will need ceramic capacitors with a capacity of 0.1 mF and an operating voltage of 1600 V. In order for a high-power alternating current to form in the coil, 7 such capacitors are required.
4. During the operation of such an induction device, field-effect transistors will get very hot and if aluminum alloy radiators are not attached to them, then after a few seconds of operation at maximum power, these elements will fail. Transistors should be placed on heat sinks through a thin layer of thermal paste, otherwise the efficiency of such cooling will be minimal.
5. Diodes, which are used in an induction heater, must be of ultra-fast action. The most suitable for this circuit, diodes: MUR-460; UV-4007; HER-307.
6. Resistors used in circuit 3: 10 kOhm with a power of 0.25 W - 2 pcs. and 440 ohm power - 2 watts. Zener diodes: 2 pcs. with an operating voltage of 15 V. The power of the zener diodes must be at least 2 watts. A choke for connecting to the power outputs of the coil is used with induction.
7. To power the entire device, you will need a power supply unit with a capacity of up to 500. W. and voltage 12 - 40 V. You can power this device from a car battery, but you will not be able to get the highest power readings at this voltage.

The very process of manufacturing an electronic generator and coil takes a little time and is carried out in the following sequence:

1. From a copper pipe a spiral with a diameter of 4 cm is made. To make a spiral, a copper tube should be wound onto a rod with a flat surface with a diameter of 4 cm. The spiral should have 7 turns that should not touch. Mounting rings are soldered to the 2 ends of the tube for connection to the transistor radiators.
2. The printed circuit board is made according to the scheme. If it is possible to supply polypropylene capacitors, then due to the fact that such elements have minimal losses and stable operation at large amplitudes of voltage fluctuations, the device will work much more stable. The capacitors in the circuit are installed in parallel, forming an oscillatory circuit with a copper coil.
3. Metal heating occurs inside the coil, after the circuit is connected to a power supply or battery. When heating the metal, it is necessary to ensure that there is no short circuit of the spring windings. If you touch the heated metal 2 turns of the coil at the same time, then the transistors fail instantly.

Nuances

1. When conducting experiments on heating and hardening metals, inside the induction coil the temperature can be significant and amounts to 100 degrees Celsius. This heating effect can be used to heat domestic water or to heat a house.
2. Scheme of the heater discussed above (Figure 3), at maximum load it is able to provide the radiation of magnetic energy inside the coil equal to 500 watts. Such power is not enough to heat a large volume of water, and the construction of a high power induction coil will require the manufacture of a circuit in which it will be necessary to use very expensive radio elements.
3. A budget solution for organizing induction heating of a liquid, is the use of several devices described above, arranged in series. In this case, the spirals must be on the same line and not have a common metal conductor.
4. Asa stainless steel pipe with a diameter of 20 mm is used. Several induction spirals are “strung” onto the pipe, so that the heat exchanger is in the middle of the spiral and does not come into contact with its turns. With the simultaneous inclusion of 4 such devices, the heating power will be about 2 kW, which is already enough for flow heating of the liquid with a small circulation of water, to values ​​​​allowing the use of this design in the supply warm water small house.
5. If we connect such heating element with well insulated tank, which will be located above the heater, the result will be a boiler system in which the heating of the liquid will be carried out inside the stainless pipe, the heated water will rise up, and a colder liquid will take its place.
6. If the area of ​​the house is significant, the number of induction coils can be increased up to 10 pieces.
7. The power of such a boiler can be easily adjusted by turning off or on the spirals. The more sections that are simultaneously turned on, the greater the power of the heating device operating in this way will be.
8. To power such a module, you need a powerful power supply. If there is an inverter welding machine direct current, then it is possible to make a voltage converter of the required power from it.
9. Due to the fact that the system operates on direct electric current, which does not exceed 40 V, the operation of such a device is relatively safe, the main thing is to provide a fuse box in the generator power circuit, which, in the event of a short circuit, will de-energize the system, thereby eliminating the possibility of a fire.
10. It is possible to organize “free” heating of the house in this way, provided that batteries are installed to power induction devices, which will be charged using solar and wind energy.
11. Batteries should be combined in sections of 2, connected in series. As a result, the supply voltage with such a connection will be at least 24 V., which will ensure the operation of the boiler at high power. In addition, series connection will reduce the current in the circuit and increase the battery life.

1. Exploitation homemade devices induction heating, does not always make it possible to exclude the spread of electromagnetic radiation harmful to humans, therefore the induction boiler should be installed in non-residential premises and shielded with galvanized steel.
2. Mandatory when working with electricity safety regulations must be followed and, especially for 220 V AC networks.
3. As an experiment can be made hob for cooking food according to the scheme specified in the article, but operate this device permanently not recommended due to imperfection self-manufacturing shielding of this device, because of this, exposure to the human body of harmful electromagnetic radiation that can adversely affect health is possible.

The induction furnace is used for melting non-ferrous and ferrous metals. Units of this principle of operation are used in the following areas: from the finest jewelry to industrial smelting of metals in large sizes. This article will discuss the features of various induction furnaces.

Induction furnaces for metal melting

Principle of operation

Induction heating is the basis for the operation of the furnace. In other words, electricity generates an electromagnetic field and heat is obtained, which is used on an industrial scale. This law of physics is studied in the last grades of a comprehensive school. But the concept of an electrical unit and electromagnetic induction boilers should not be confused. Although the basis of the work here and there is electricity.

How does this happen

The generator is connected to an alternating current source, which enters it through an inductor located inside. The capacitor is used to create an oscillation circuit, which is based on a constant operating frequency, to which the system is tuned. When the voltage in the generator rises to a limit of 200 V, the inductor creates an alternating magnetic field.

The circuit is closed, most often, by means of a core made of a ferromagnetic alloy. An alternating magnetic field begins to interact with the workpiece material and creates a powerful electron flow. After the entry into the inductive action of the electrically conductive element in the system, occurrence of residual stress, which in the capacitor contributes to the occurrence of eddy current. Eddy current energy is converted into thermal energy inductor and heating to high melting temperatures of the desired metal occurs.

The heat produced by the inductor is used:

• for melting soft and hard metals;
• for surface hardening metal parts(for example, a tool);
• for thermal processing of already produced parts;
• household needs (heating and cooking).

Brief description of various furnaces

Varieties of devices

Induction crucible furnaces

It is the most common type of furnace induction heating. hallmark, different from other types is that in it an alternating magnetic field appears in the absence of a standard core. Cylindrical crucible placed inside the inductor cavity. The furnace, or crucible, is made of a material that resists fire perfectly and is connected to an alternating electric current.

Positive aspects

Crucible aggregates include to environmentally friendly heat sources, environment not contaminated by metal melting.

There are disadvantages in the operation of crucible furnaces:

• low-temperature slags are used during technological processing;
• the produced lining of crucible furnaces has a low resistance to destruction, most of all it is noticeable at sharp temperature fluctuations.

The existing disadvantages are not particularly difficult, the advantages of a crucible induction unit for melting metal are obvious and have made this type of device popular and in demand among a wide range of consumers.

Channel furnaces for induction melting

This type has found wide application in the smelting of non-ferrous metals. It is effectively used for copper and copper alloys based on brass, cupronickel, bronze. Aluminum, zinc and alloys in the composition of these metals are actively melted in channel units. Widespread use of furnaces of this type is limited due to the impossibility of making a fracture-resistant lining on the inner walls of the chamber.

Molten metal in induction type channel furnaces thermal and electrodynamic motion, which ensures constant uniformity of mixing of the alloy components in the furnace bath. Use of channel ovens induction principle justified in cases where special requirements are imposed on the molten metal and manufactured ingots. The alloys are of high quality in terms of gas saturation coefficient, the presence of organic and synthetic impurities in the metal.

Induction channel furnaces work like a mixer and are designed to level the composition, maintain a constant process temperature, and select the pouring speed into molds or molds. For each alloy and casting composition, there are parameters of a special charge.

Advantages

• heating of the alloy occurs in the lower part, to which there is no air access, which reduces evaporation from the upper surface, heated to a minimum temperature;
• channel furnaces are classified as economical induction furnaces, since the ongoing melting is ensured by a small consumption of electrical energy;
• the furnace has a high coefficient useful action due to the use of a closed circuit of a magnetic wire in the work;
• the constant circulation of molten metal in the furnace accelerates the smelting process and contributes to the homogeneity of the mixing of the alloy components.

Flaws

• the durability of the stone inner lining is reduced when using high temperatures;
• the lining is destroyed during the melting of chemically aggressive alloys of bronze, tin and lead.
• when melting a contaminated low-grade charge, clogging of the channels occurs;
• surface slag in the bath does not heat up to a high temperature, which does not allow operations to be carried out between the metal and the cover and to melt chips and scrap;
• channel units do not tolerate interruptions in operation, which makes it necessary to constantly store a significant amount of liquid alloy in the furnace mouth.

The complete removal of molten metal from the furnace leads to its rapid cracking. For the same reason, it is impossible to perform a quick conversion from one alloy to another, you have to make several intermediate heats, called ballast.

Vacuum induction furnaces

This type is widely used for melting high quality steels and nickel, cobalt and iron alloys of heat-resistant quality. The unit successfully copes with the melting of non-ferrous metals. Glass is melted in vacuum units, parts are treated with high temperature, produce single crystals.

The furnace is referred to as a high-frequency generator located in an inductor isolated from the external environment, passing a high-frequency current. To create a vacuum, air masses are pumped out of it with pumps. All operations for the introduction of additives, charge loading, metal issuance are carried out by automatic mechanisms with electric or hydraulic control. From vacuum furnaces, alloys are obtained with small impurities of oxygen, hydrogen, nitrogen, and organic matter. The result is far superior to open ovens induction action.

Heat resistant steel from vacuum furnaces used in tool and weapons production. Some nickel alloys containing nickel and titanium are reactive and difficult to obtain in other types of furnaces. Vacuum furnaces perform pouring of metal by turning the crucible in the inner space of the casing or by rotating the chamber with a fixed furnace. Some models have an opening in the bottom to drain the metal into the installed container.

Crucible furnaces with transistor converter

Applied to a limited weight of non-ferrous metals. They are mobile, light in weight and easily moved from place to place. The oven is supplied with a high-voltage transistor universal action transducer. Allows you to select the power recommended for connection to the network, and, accordingly, the type of converter, which is necessary in this case with a change in the parameters of the weight of the alloy.

Transistor induction furnace widely used for metallurgical processing. With its help, parts are heated in blacksmithing, hardened metal objects. Crucibles in transistorized furnaces are made of ceramic or graphite, the former being designed to melt ferromagnetic metals such as cast iron or steel. Graphite is set to melt brass, copper, silver, bronze and gold. Glass and silicon are melted on them. Aluminum melts well with cast iron or steel crucibles.

What is the lining of induction furnaces

Its purpose is to protect the furnace casing from the damaging effects of high temperatures. side effect is the preservation of heat, therefore, increases the efficiency of the process.

The crucible in the design of the induction furnace is made in one of the following ways:

• extraction method in small furnaces;
• in a rammed way from refractory material in the form of masonry;
• combined, combining ceramics and a buffer layer lining between the masonry and the indicator.

The lining is made of quartzite, corundum, graphite, fireclay graphite, magnesite. All these materials are mixed with additives that improve lining characteristics, reduce volume changes, improve sintering, and increase the layer's resistance to aggressive materials.

To select one or another lining material take into account a number of related conditions, namely, the type of metal, the price and refractory properties of the crucible, the service life of the composition. A properly selected lining composition should provide technical requirements for the process:

• obtaining high quality ingots;
• the largest number of full-fledged melting without repair work;
• safe work of specialists;
• stability and continuity of the melting process;
• receiving quality material when using an economical amount of resources;
• application for lining common materials at a low price;
• minimal impact on the environment.

The use of induction furnaces allows you to get alloys and metals of excellent quality with a minimum content of various impurities and oxygen, which increases their use in complex areas of production.

The world has already formed well-established technologies for the production of metal and steel, which are used by metallurgical enterprises today. These include: a converter method for producing metal, rolling, drawing, casting, stamping, forging, pressing, etc. However, the most common under modern conditions is the remelting of metal and steel in convectors, open-hearth furnaces and electric furnaces. Each of these technologies has a number of disadvantages and advantages. However, the most advanced and latest technology today is the production of steel in electric furnaces. The main advantages of the latter over other technologies are high productivity and environmental friendliness. Consider how to assemble a device where metal will be melted at home with your own hands.

Small-sized induction electric furnace for melting metals at home

Melting metals at home is possible if you have an electric furnace that you can do yourself. Consider the creation of an inductive small-sized electric furnace for the production of homogeneous alloys (OS). Compared with analogues, the created installation will differ in the following features:

• low cost (up to 10,000 rubles), while the cost of analogues is from 150,000 rubles;
• possibility of regulation temperature regime;
• the possibility of high-speed melting of metals in small volumes, which allows the installation to be used not only in the scientific field, but also, for example, in the jewelry, dental fields, etc.
• uniformity and speed of heating;
• the possibility of placing the working body in the furnace in a vacuum;
• relatively small dimensions;
• low noise level, almost complete absence of smoke, which will increase labor productivity when working with the installation;
• the ability to work both from a single-phase and from a three-phase network.

Schematic type selection

Most often, when building induction heaters, three main types of circuits are used: half-bridge, asymmetric bridge and full bridge. When designing this installation, two types of circuits were used - a half-bridge and a full bridge with frequency regulation. This choice was driven by the need for power factor control. The problem arose of maintaining the resonance mode in the circuit, since it is with its help that the required power value can be adjusted. There are two ways to control resonance:

• by changing the capacitance;
• by changing the frequency.

In our case, resonance is maintained by adjusting the frequency. It was this feature that caused the choice of the type of circuit with frequency regulation.

Analysis of the components of the circuit

Analyzing the operation of an induction furnace for melting metal at home (IP), three main parts can be distinguished: a generator, a power supply unit, and a power unit. To provide the required frequency during the operation of the installation, a generator is used, which, in order to avoid interference from other units of the installation, is connected to them through a galvanic solution in the form of a transformer. To provide the power voltage circuit, a power supply unit is required, which ensures the safe and reliable operation of the power elements of the structure. Actually, it is the power unit that generates the necessary powerful signals to create the desired power factor at the output of the circuit.

Figure 1 shows the general circuit diagram induction plant.

Create a wiring diagram

Wiring diagram (wiring) showing connections constituent parts products and defines the wires, cables that make these connections, as well as the places of their connection.

For the convenience of further installation of the installation, a connection diagram was developed, reflecting the main contacts between the functional blocks of the furnace (Fig. 2).

Frequency generator

The most complex IP block is the generator. It provides the desired frequency of operation of the installation and creates the initial conditions for obtaining a resonant circuit. As a source of oscillations, a specialized controller of electronic impulses of the KR1211EU1 type is used (Fig. 3). This choice was due to the ability of this microcircuit to operate in a fairly wide frequency range (up to 5 MHz), which makes it possible to obtain a high power value at the output of the power block of the circuit.

Figures 4.5 show a schematic diagram of a frequency generator and a diagram of an electrical board.

The KR1211EU1 microcircuit generates signals of a given frequency, which can be changed using a control resistor installed outside the microcircuit. Further, the signals fall on transistors operating in the key mode. In our case, silicon field-effect transistors with an insulated gate type KP727 are used. Their advantages are as follows: the maximum allowable impulse current that they can withstand is 56 A; the maximum voltage is 50 V. The range of these indicators suits us completely. But, in connection with this, there was a problem of significant overheating. It is to solve this issue that a key mode is needed, which will reduce the time spent by transistors in working condition.

Power Supply

This block provides power supply to the executive units of the installation. Its main feature is the ability to work from a single-phase and three-phase network. A 380V power supply is used to improve the power factor dissipated in the inductor.

The input voltage is applied to the rectifier bridge, which converts the 220V AC voltage into a pulsating DC voltage. Storage capacitors are connected to the outputs of the bridge, which maintain a constant voltage level after the load is removed from the installation. To ensure the reliability of the installation, the unit is equipped with an automatic switch.

Power block

This block provides direct amplification of the signal and the creation of a resonant circuit, by changing the capacitance of the circle. The signals from the generator go to transistors that operate in amplification mode. Thus, they, opening at different times, excite the corresponding electrical circuits passing through the step-up transformer and pass power current through it in different directions. As a result, at the output of the transformer (Tr1), we get an increased signal with a given frequency. This signal is applied to the installation with an inductor. An installation with an inductor (Tr2 in the diagram) consists of an inductor and a set of capacitors (C13 - Sp). Capacitors have a specially selected capacitance and create an oscillating circuit that allows you to adjust the level of inductance. This circuit must operate in resonance mode, which causes a rapid increase in the frequency of the signal in the inductor, and an increase in induction currents, due to which the actual heating occurs. Figure 7 shows circuit diagram power block of the induction furnace.

Inductor and features of its work

Inductor - a special device for transferring energy from a power source to a product, it heats up. Inductors are usually made from copper tubes. During operation, it is cooled by running water.

The melting of non-ferrous metals at home using an induction furnace consists in the penetration of induction currents into the middle of the metals, which arise due to the high frequency of the voltage change applied to the inductor terminals. The power of the installation depends on the magnitude of the applied voltage and on its frequency. Frequency affects the intensity of induction currents and, accordingly, the temperature in the middle of the inductor. The greater the frequency and operating time of the installation, the better the metals are mixed. The inductor itself and the directions of the flow of induction currents are shown in Figure 8.

For uniform mixing and to avoid contamination of the alloy by foreign elements, such as electrodes from an alloy tank, a reverse coil inductor is used as shown in Figure 9. It is thanks to this coil that an electromagnetic field is created that keeps the metal in the air, surpassing the force of gravity of the Earth.

Final assembly of the plant

Each of the blocks is attached to the body of the induction furnace using special racks. This is done in order to avoid unwanted contacts of current-carrying parts with the metal coating of the case itself (Fig. 10).

For safe work once installed, it is completely enclosed by a robust housing (Fig. 11), thus creating a barrier between dangerous structural elements and the body of the person working with it.

For the convenience of setting up the induction installation as a whole, an indication panel was made to accommodate metrological devices, with the help of which all parameters of the installation are controlled. Such metrological devices include: an ammeter that shows the current in the inductor, a voltmeter connected to the output of the inductor, a temperature indicator, and a signal generation frequency regulator. All the above parameters make it possible to regulate the operating modes of the induction installation. Also, the design is equipped with a manual activation system, and a system for indicating heating processes. With the help of impressions on devices, the operation of the installation as a whole is actually monitored.

The design of a small-sized induction installation is quite complicated. technological process, since it must ensure compliance a large number criterion, such as: convenience of design, small size, portability, etc. This installation works on the principle of non-contact energy transfer to an object that heats up. As a result of the purposeful movement of induction currents in the inductor, the melting process itself takes place directly, the duration of which is several minutes.

The creation of this installation is quite profitable, since its scope is unlimited, from use for routine laboratory work to the production of complex homogeneous alloys from refractory metals.

A household induction stove can easily heat a home. In industry, these devices are involved in the smelting of various metals. Additionally, they can participate in the heat treatment of parts, as well as their hardening. The main advantage of an induction type oven is its ease of use. In addition, they are easy to maintain and do not require periodic inspections, which is very important.

There is absolutely no need to allocate a separate room for the installation of this device. The performance of these devices is very good. This is largely due to the fact that there are no parts in the design that are subject to mechanical wear. In general, induction-type furnaces are safe for human health and do not pose a danger during operation.

How it works?

The operation of the induction furnace begins with the supply of alternating current to the generator. At the same time, it passes through a special inductor, which is located inside the structure. Next, a capacitor is used in the device. Its main task is to form an oscillatory circuit. In this case, the entire system is tuned to the operating frequency. The inductor in the furnace creates an alternating magnetic field. At this time, the voltage in the device rises to 200 V.

To complete the circuit, the system has a ferromagnetic core, however, it is not installed on all models. Subsequently, the magnetic field interacts with the workpiece and creates a powerful flux. Next, the electrically conductive element is induced and a secondary voltage occurs. This creates an eddy current in the capacitor. According to the Joule-Lenz law, he gives his energy to the inductor. As a result, the workpiece in the furnace heats up.

Homemade induction type ovens

Do-it-yourself induction furnace is made strictly according to the drawings in compliance with safety rules. The body of the device should be selected from aluminum alloy. A large platform should be provided at the top of the structure. Its thickness must be at least 10 mm. Most often, a steel template is used to stuff the crucible. To drain the molten metal, a lining cavity in the form of a spout is required. In this case, the structure must have a pad for stuffing.

For sections, an insulating stand is installed above the template. Directly below it will be a hinged support. In order to cool the inductor, the furnace must have a fitting. Voltage is supplied to the device through the bridge, which is located at the bottom of the device. To tilt the container, a do-it-yourself induction furnace must have a separate gearbox. In this case, it is best to make a handle so that it is possible to merge the metal manually.

Furnaces of the company "Termolit"

Induction furnaces for melting metal of this brand have an acceptable converter power. At the same time, the capacity of the cameras in the models can vary greatly. The average metal melting rate is 0.4 t/h. At the same time, the nominal voltage of the supply network fluctuates around 0.3 V. The water consumption in an induction type furnace depends on the cooling system. Usually this parameter is 10 cubic meters / h. At the same time, the specific power consumption is quite high.

Characteristics of the furnace "Termolit TM1"

This melting furnace (induction) has a total capacity of 0.03 tons. At the same time, the converter power is only 50 kW, and the average melting speed is 0.04 tons per hour. The voltage of the supply medium must be at least 0.38 V. The water consumption for cooling in this model is negligible. This is largely due to the low power of the device.

Of the shortcomings, a high power consumption should be highlighted. On average, approximately 650 kW are consumed per hour of operation of the furnace. The frequency converter in this model has a class "TPCh-50". In general, "Termolit TM1" is an economical equipment, but with poor performance.

Induction furnace "TG-2"

Induction melting furnaces of the TG series are produced with a chamber capacity of 0.6 tons. The rated power of the device is 100 kW. At the same time, it is possible to melt 0.16 tons of non-ferrous metals per hour of continuous operation. This model is powered by a network with a voltage of 0.3 V.

The water consumption of the TG-2 furnace of the induction type is quite significant and, on average, up to 10 cubic meters liquids. All this is due to the need for intensive cooling of the gearbox. positive side is moderate power consumption. Typically, up to 530 kW of electricity is consumed per hour of operation. The frequency converter in the "TG-2" model is installed in the "TPCh-100" class.

Furnaces "Thermo Pro"

The main modifications of the equipment from this company are induction melting furnaces SAT 05, SAK-1, and SOT 05. Their average nominal melting point is 900 degrees. At the same time, the power of the devices fluctuates around 150 kW. In addition, it should be noted their good performance. For an hour of work of non-ferrous metals, 80 kg can be melted. At the same time, many Thermo Pro models are made for narrowly targeted use. Some of them are designed exclusively for working with aluminum, while other modifications are used to melt lead or tin.

Modification "SAT 05"

This induction furnace is designed for aluminum melt. The power of this device is exactly 20 kW. At the same time, up to 20 kg of metal can be passed per hour of work. The capacity of the chamber in the "SAT 05" model is 50 kg, and the frequency converter is of the "TFC" class.

Batteries in the device are installed capacitor type. In the lower part of the structure, the manufacturer installed a special water-cooled cable. The control panel in this model is available. Among other things, it should be noted a large set of furnace "SAT 05". It includes all mounting accessories, as well as operating documents.

Parameters of the furnace "SAK-1"

This induction furnace is most commonly used for melting lead as well as tin. In some cases, it is allowed to lay copper, but the performance drops significantly. The average melting temperature fluctuates around 1000 degrees, this device has a power of 250 kW. For an hour of continuous operation, it is possible to skip up to 400 kg of non-ferrous metals. At the same time, the capacity of the equipment allows loading up to 1000 kg of material. The supply voltage is 0.3 kV.

Water consumption for cooling the SAK-1 model is insignificant. The oven consumes approximately 10 cubic meters of liquid per hour. The specific power consumption is also small and amounts to 530 kW. The frequency converter in this design is provided for the brand "TPC-400". In general, the SAK-1 model turned out to be economical and easy to use.

Overview of the "SAK 05" model

Induction furnaces for melting metal "SAK 05" have a large capacity - 0.5 tons. At the same time, the power of the supply converter is 400 kW. The working speed of melting in this furnace is quite high. The rated voltage of the device is 0.3 kV. For an hour of water operation, approximately 11 cubic meters are consumed to cool the system. It should also be noted that the power consumption is considerable and amounts to 530 kW. The frequency converter in the device has a class "TPCh-400". At the same time, it is able to pump the maximum temperature up to 800 degrees. The induction furnace "SAK 05" is designed exclusively for melting aluminum and bronze. The heat exchange cabinet is installed by the manufacturer brand "IM". It should also be noted convenient remote control. There is an alarm system and a hydraulic station in the system.

Among other things, a set of turbo tires and mounting accessories are included as standard. In general, the SAK 05 model turned out to be quite secure, and you can use it without risk to health. This was largely achieved through rods that are mounted on hydraulic cylinders. At the same time, the metal practically does not splash. Direct frequency adjustment during operation occurs in automatic mode. Capacitors are used in this medium voltage model.

Developed over a century ago, induction stoves are firmly established in our everyday life. This became possible thanks to the development of electronics. The explosive growth in the power of controllers based on silicon semiconductors and the appearance in the wide market of transistors capable of providing high powers (several kilowatts) in last years took on the character of an avalanche. All this gave humanity incredibly great prospects for the development of miniature installations comparable in power to industrial devices of the recent past.

Use and structure of the device

The use of induction furnaces in the household avoids the appearance of open flames in the room and is quite effective way melting and controlled heating of metals and alloys. This is due to the fact that the metal is heated, heated and melted not under the influence of high-temperature burners, but by passing high-frequency currents through itself, stimulating the active movement of particles in the structure of the material.

It became possible to appear in everyday life:

In addition, electric induction stoves are becoming more common, which work not only with conductive material. Their device is slightly different from conventional induction furnaces, since it is based on heating by electric induction of a material that does not conduct current (they are also called dielectrics) between capacitor plates, that is, its conclusions of different polarity. At the same time, the temperatures reached are not very high (about 80-150 degrees Celsius), therefore, such installations are used for melting plastic or its heat treatment.

Design features and principle of operation

The induction furnace works on the basis of the formation of eddy electric currents in it. To do this, use an inductor consisting of turns of a thick wire, to which an alternating current source is supplied. It is the alternating current that forms a magnetic field that is constantly changing depending on the current frequency. It provokes the transfer of these currents to the substance placed inside the coil, along with a large amount of heat. In this case, even the most ordinary welding inverter can act as a generator.

There are two types of induction furnaces:

1. With a magnetic core, a feature of which is the location of the inductor inside the volume of metal that can be melted.
2. Without a magnetic circuit - when the inductor is outside.

The design with the presence of a magnetic circuit is used, for example, in channel furnaces. They use an open metal (most often steel) magnetic circuit, inside which there is a crucible for melting and an inductor that form the primary circuit of the winding. The crucible material can be graphite, heat-resistant clay, or any other non-conductive material with suitable heat resistance. It contains the metal that needs to be melted. These are, as a rule, all kinds of non-ferrous metal alloys, duralumin and cast iron.

The generator of such a furnace must provide AC frequency within 400 hertz. There are also options for using a conventional generator instead of a generator. electrical network and feed the furnace with a current with a frequency of 50 hertz, but in this case the heating temperature will be lower and such an installation will not work for more refractory alloys.

Crucible furnaces, which do not have a magnetic circuit in their design, have become much more widespread among enthusiasts. They use currents of much higher frequency to achieve higher field densities. This is due precisely to the absence of a magnetic circuit - too much of the field energy is dissipated in space. To counteract this, the furnace must be very finely tuned:

• Ensure that the frequency of the induction circuit and the voltage from the generator are equal (when using an inverter, this is easiest to do).
• Select the diameter of the melting crucible so that it is close to the wavelength of the received magnetic field radiation.

In this way, losses can be minimized up to 25% of the total power. To achieve the best result, it is recommended to set twice, or even three times, the higher frequency of the AC source than the resonant one. In this case, the diffusion of the metals that make up the alloy will be maximum, and its quality will be much better. If you increase the frequency further, you can achieve the effect of pushing the high-frequency field to the surface of the product and so harden it.

Vacuum melting furnaces

This type of installation can hardly be called domestic, but it is worth considering because vacuum melting has a number of technological advantages compared to other types. By its design, it resembles a crucible, with the difference that the furnace itself is located in a vacuum chamber. This makes it possible to achieve greater purity of the metal melting process, reduce its oxidizability during processing and speed up the process, achieving significant energy savings.

In addition, the limited and closed space helps to avoid the release of harmful fumes of melting metals into the surrounding space and maintain the cleanliness of their processing. The ability to control the composition and processing process is also one of the advantages of this type of ovens.

Channel induction units

Another type of industrial oven that has a wider application than others. They can be used not only as smelters, but also as distributors of prepared material and mixers of several types of raw materials. Typical designs of such devices include:

The slightest opening of the circuit, which is formed by liquid metal, a magnetic circuit and a coil, leads to an increase in its own resistance and an instantaneous ejection of the entire mass of raw materials from the channel. To counteract this phenomenon, a "swamp" is left inside the channel - a small mass of metal, which is maintained in liquid form.

Advantages of channel-type induction furnaces:

• Low installation cost.
• Efficiency - to maintain the temperature inside the bath, which does not dissipate heat well, you need a small amount of electricity.
• The efficiency of the inductor during operation is very high.

Flaws:

The main elements of the furnace scheme

In order to assemble the installation and perform work on it, it is necessary to find a suitable scheme of the induction furnace and parts for it. To find the latter, it is very useful to have one or more unnecessary power supplies from the computer, since most of the details can be found in them. Typical scheme the simplest oven with a homemade inverter will include elements such as:

The inverter for the installation is assembled according to the scheme proposed by S. V. Kukhtetsky for laboratory tests. It can be easily found on the Internet. The power of the inverter, which is powered by a voltage in the range of 12-35 volts, will be 6 kilowatts, and its operating frequency will be 40-80 kilohertz, this will be more than enough for home projects.

Work safety

Since working with induction oven implies close contact with molten metal and currents of high frequency and strength, it is worth taking care of high-quality grounding of the installation and reliable means of protection. In this case, clothing must strictly comply with all requirements:

Do not forget about the good ventilation of the room in which they will work. Molten metal releases chemicals into the air that are not good for your lungs.