PDF | A new generation of industrial induction melting furnaces has been developed during the last 25 years. Present practices followed in Induction Furnaces. The electric induction furnace is a type of melting furnace that uses electric currents to melt metal. Induction furnaces are ideal for melting and alloying a wide. INDUCTION FURNACE. An Induction Furnace uses induction to heat a metal to its melting point which is based on the theory of. Electro Magnetic Induction.
|Language:||English, Spanish, German|
|Genre:||Business & Career|
|Distribution:||Free* [*Sign up for free]|
The main task of the present work is to design and construct a coreless induction furnace. Many analytical methods could be applied to induction heating and. In ,Edward Allen Colby patented an induction furnace for melting metals. The first .. enbillitaco.tk ISSN: Induction furnaces come in all sizes and are very versatile tools for foundries. generalized description of modern induction furnace cooling systems and.
In a cross-flow cooling tower air moves horizontally through the fill as the water moves downward. Cooling towers are also characterized by the means by which air is moved.
Because evaporation consists of pure water, the concentration of dissolved minerals and other solids in circulating water will tend to increase unless some means of dissolved- Fig Some water is also lost by droplets being carried out with the exhaust air drift. Mechanical- draft cooling towers rely on power-driven fans to draw or force the air through the tower.
A fan-assisted natural-draft cooling tower employs mechanical draft to augment the buoyancy effect. The high voltage current cables used in the furnace is covered by a water cable that is water flows in between the current cable and water cable. Fig Power control methods It is often desirable to control the amount of power processed by an induction heater. This determines the rate at which heat energy is transferred to the work piece.
The power setting of this type of induction heater can be controlled in a number of different ways: This can be done by running the inverter from a variable voltage DC supply such as a controlled rectifier using thyristors to vary the DC supply voltage derived from the mains supply. The impedance presented to the inverter is largely constant with varying power level, so the power throughput of the inverter is roughly proportional to the square of the supply voltage.
However, that the exact power throughput in kilowatts depends not only on the DC supply voltage to the inverter, but also on the load impedance that the work coils presents to the inverter through the matching network. Therefore if precise power control is required the actual induction heating power must be measured, compared to the requested "power setting" from the operator and an error signal fed back to continually adjust the DC link voltage in a closed-loop fashion to minimize the error.
This is necessary to maintain constant power because the resistance of the work piece changes considerably as it heats up. Power is only sourced to the work coil in the time that the devices are switched on. The load current is then left to freewheel through the devices body diodes during the dead time when both devices are turned off.
However, a significant drawback of this method is the commutation of heavy currents between active devices and their free-wheel diodes. Forced reverse recovery of the free-wheel diodes that can occur when the duty ratio is considerably reduced. For this reason duty ratio control is not usually used in high power induction heating inverters.
As the operating frequency of the inverter is moved away from the resonant frequency of the tank circuit, there is less resonant rise in the tank circuit, and the current in the work coil diminishes. Therefore less circulating current is induced into the work piece and the heating effect is reduced.
This causes the inductive reactance at the input of the matching circuit to become increasingly dominant as the frequency increases. Therefore the current drawn from the inverter by the matching network starts to lag in phase and diminish in amplitude.
Both of these factors contribute to a reduction in the real power throughput. In addition to this the lagging power factor ensures that the devices in the inverter still turn on with zero voltage across them, and there are no free- wheel diode recovery problems. The L-match network between the inverter and the tank circuit technically consists of an inductive and a capacitive part. But the capacitive part is in parallel with the work coil's own tank capacitor, and in practice these are usually one and the same part.
Therefore the only part of the matching network that is available to adjust is the inductor. The matching network is responsible for transforming the load impedance of the work coil to a suitable load impedance to be driven by the inverter.
Altering the inductance of the matching inductor adjusts the value to which the load impedance is translated.
In general, decreasing the inductance of the matching inductor causes the work coil impedance to be transformed down to a lower impedance. This lower load impedance being presented to the inverter causes more power to be sourced from the inverter.
Conversely, increasing the inductance of the matching inductor causes a higher load impedance to be presented to the inverter. This lighter load results in a lower power flow from the inverter to the work coil. The degree of power control achievable by altering the matching inductor is moderate. There is a also a shift in the resonant frequency of the overall system.
The losses are: These conditions are also and losses on main side transformer. The inoculation addition mechanism, use of half of present losses, thus improving the conducive for melting low weight material losses are represented in Figure 3. The Induction furnace 85 per cent. The Medium frequency induction furnace Efficient operation of coreless furnace consists of four types of parts: Silicon Controlled Rectifier practices. The steps involved in operation b Electric: Transformer, convertor, reduction in rejection in castings caused type SCR and Insulated Gate Bipolar of induction furnace are shown in Figure 4.
IGBT type is more energy efficient than c Control systems: ABP Induction - High energy efficient melt-shop design and operation Defe in marginally less number of foundries produced nearly 10 million huge investments. But this is only because of small production scale, as scale starts mt. This increase in productivity is nearly to increase, automation helps in reducing entirely because of increasing trends per unit cost of production.
In India we of mechanization and automation in have advantage of huge population foundries. Germany produce with 20 to 45 hours, But cost of labour i0s on rise and the Clear advantages of avoiding depending on product size and profile. Around 75 per cent of foundries in be so high that foundry will have to think India are estimated to operate manually in favour of automation. Automation Clean cast surfaces and from the remaining 25 per cent demand in Indian foundries is increasing Low reject and cleaning costs substantial majority is semi-automatic and it will continue to increase.
Medium Increased productivity and cost efficiency throughout technology and around foundries and large foundry should move from the entire casting process use high pressure moulding line and latest semi-automatic pouring system to fully global technologies.
Foundry Automation in pouring system is being historically has an image of 3Ds viz-a- offered by number of manufacturers, viz, dirty, dark and dangerous, hence such as pressure pour, opti-pour, auto- this has not helped to attract younger pour and multi-pour.
India workforce. Similar initiatives articles: Revitalization of the over the next 20 years.
Of course, India Need for encouraging should be at the centre stage for much of policies this infrastructure spends and foundries Innovation at initial stage requires should benefit from this. This means good days are ahead for the The automobile sector demand has the foundry industry. Even globally, the automobile largest casting producers but it should on process re-engineering, fortification, sector demand accounts for one-third of be noted that there is only one National technology up-gradation and creating total castings demand.
It is anticipated that Institute of Foundry and Forge Technology safe and work-friendly environment by construction, infrastructure, earthmovers, E Nand Gopal in Ranchi.
Most engineers employed are adopting lean manufacturing practices pumps and agriculture will pick up Research Associate, The Energy and Resources not formally trained and exposed to best or Kaizen activities in all functional areas faster. Institute, New Delhi practices of foundry. Kolhapur and Coimbatore are two pioneer examples in this field. With increase in automation in foundry, the requirement of manpower will come down, but the necessity would be of highly skilled set of manpower.
Unskilled manpower does hold any position in an automated foundry. Every cluster must have foundry-related courses in selected colleges to train manpower.
For example, in Coimbatore every year around students join the 3-year course on foundry in selected colleges. The entire course is funded by select foundries and the job is also guaranteed. Schemes such as the above- mentioned are necessary in other clusters also to motivate youth to work in foundry, at the same time foundries get skilled manpower. The courses should include management aspects, state-of-the-art casting simulation study and case studies on present-day requirement of foundries.
These will deal with showcasing that foundry is not using age-old technology, but there is modernization in foundries which will increase the interest of students for the course. Also, the concept of green foundry is taking all possible energy efficiency concepts for design stage while setting up a new foundry. Germany has seven times less foundry than India, but their productivity is four times that of our foundry. Download pdf. Remember me on this computer.
Enter the email address you signed up with and we'll email you a reset link. Need an account?