New furnace design for reheating and homogenizing rolling slabs
For the homogenizing and reheating of aluminium slabs ahead of the rolling mill, a new OTTO JUNKER furnace concept has been developed and successfully implemented. The innovative design combines the advantages of the formerly used pit or pusher-type furnaces without having any of their drawbacks.
The key principle lies in the use of high-convection chamber furnaces in which the slabs are heated while standing upright on their long edges and are moved into and out of the furnace individually by an automatic handling system (see picture). An appropriately designed nozzle array ensures an effective high-convection heat transfer. In the new concept, multiple furnaces are served by a single handling and loading system and more furnace chambers can be added later on.
The main features of this new furnace concept reside in its low energy consumption, accurate temperature management and high flexibility thanks to the freely selectable loading and unloading sequence. In addition, it provides a high automation level.
A model of an entire homogenizing system comprising multiple furnaces of this new type will be on exhibit at our trade fair stand.
Complete tin-coating line from a single source
In hot-dip tin coating, the copper strip passes through a bath of molten tin which settles on the metal, thereby forming a protective layer as shown in the model. The coating gauge is subsequently controlled by air wipers. From a technological viewpoint, it is important that the coating gauge can be set and controlled with high accuracy using appropriate equipment and process technology. Thanks to the wiping technique and a control system relying on non-contacting measurement, the coating can be adjusted exactly to the desired thickness.
As for equipment technology, users demand variability in terms of the coating gauges supported. They also expect hot-dip tinning lines to meet the specified coating gauge accurately, and to deliver high standards of surface quality.
Moreover, modern hot-dip tinning lines are characterized by the potential integration of process steps such as degreasing, pickling, rinsing, fluxing, coating and cooling into the automatic strip processing cycle. Strip speeds up to 200 m/min must be accomodated in this context. Here, OTTO JUNKER can build on its many years of experience and success as a market leader in sophisticated copper strip treatment lines.
Induction billet heater
Billet heaters of OTTO JUNKER design enjoy ever growing demand. This has prompted us to take their development one step further.
Our JunkerDynamicHeater(TM) presents a new concept which is particularly easy to integrate into existing extrusion lines when compared to conventional heaters. Accordingly, it provides improvements in both productivity and temperature accuracy. Thanks to intelligent drive technology and power control, these units enable the user to create a stepless and dynamic temperature taper for a truly isothermal extrusion process.
The focus of our trade fair presence will be on advances in automation of our melting, pouring and heat treatment systems for yet superior process reliability and dependability, as well as on options delivering additional energy and cost savings. New engineering solutions and interesting applications will round out the presentations.
The technical and economic advantages of medium-frequency coreless induction furnaces have led to their increasingly widespread use in the foundry and semi-finished products industries. As OTTO JUNKER developed new circuit configurations for a targeted control of the bath movement as well as alternative vacuum melting furnace designs, the path was cleared for new application fields. Technical solutions such as the power-saving coil, proven in many installations, made a definite contribution towards improved energy efficiency.
Maintenance assistance system
Today's induction furnace plants are becoming ever more sophisticated and technically challenging. Accordingly, new approaches need to be followed in maintenance and repair work as well.
A first step might be to devise a system capable of determining maintenance intervals and interventions from an analysis of the stresses acting on individual assemblies, i.e., the number of operating hours or the frequency of switching operations.
A draft design of a first maintenance assistance system of this type will be presented at OTTO JUNKER's stand, not least with a view to stimulating an opinion-forming discussion on the practicality and desirability of such solutions.
The system will be demonstrated using mobile terminal equipment on key components of an exhibited MF melting furnace installation – more specifically, the actual furnace unit, the water recooling system and a frequency converter assembly.
Latest-generation Junker Furnace Control System (JOKS)
Communication between the operator and the furnace system is further simplified and expanded by the latest-generation Junker Furnace Control System (JOKS).
Based on current Siemens Multi-Touch technology with an enlarged visual display unit and glass surface, all menu screens as well as the menu navigation system were redesigned. These efforts were guided by the principle that an intuitive operation and clear-cut visualization should be ensured by all means. Simplified communication with upstream and downstream functions were another objective. At our stand, visitors can gain a first-hand impression of this new system.
OCP Optical Coil Protection
Safety will be represented by the exhibit of an induction furnace coil featuring the proven OCP crucible monitoring technology. It shows how local heating of the refractory lining gives rise to an accurate, localized display of these hot spots, and how an alarm is triggered when the set maximum temperature is exceeded.
OTTO JUNKER's proven pouring furnace technology for cast-iron foundry applications is further refined by the advances described below.
Automation: stopper actuator, camera
The dispensing accuracy of a pouring furnace is determined, among other factors, by the technical performance of the stopper control system and its actuator. OTTO JUNKER's proprietary motor actuator system moves the stopper by a genuine linear drive unit relying on magnetic force. As a result, the actuator system operates virtually without wear but with high precision.
Along with the development of this new stopper actuator, a new camera system measuring the metal level in the mould sprue cup as input for controlling the pouring rate has undergone successful trials. This system will likewise be displayed at our stand.
For a metal stream inoculation of optimum effectiveness, it is necessary to introduce a closely defined amount of inoculant into the pouring stream throughout the pouring process. OTTO JUNKER's new inoculating system works as follows: Inoculant is pre-metered into an intermediate vessel from where a frequency controlled fine-metering screw drive delivers it to a precision weighing system for accurate control and logging of the inoculant quantity. The system thus provides control of the inoculation rate while also recording the amount of inoculant actually added to each pour. Demonstrations at our stand will illustrate its high metering accuracy.
On very high output moulding lines, the available cycle time may be shorter than the required pouring time. Through the use of travelling tundishes, the requisite pouring times can nevertheless be attained. An alternative solution is to double the available pouring time by advancing two moulds or mould boxes simultaneously so that the cycle will comprise two concurrent moulding operations. For the pouring furnace, this means that two moulds must be filled at the same time, with a possible change in the sprue cup position.
This requirement is addressed by a patented OTTO JUNKER solution involving two independently movable stoppers. The extent to which the concept can actually be adopted in practice remains to be confirmed by industrial trials.
In many cases, a necessary relining of the inductor or the pouring vessel or similar repair and maintenance operations will call for a vessel replacement. This is a time-consuming process which may result in down times of the moulding machine. Where such replacements are frequent, e.g., due to short inductor lifetime, the associated losses may be hard to accept.
These considerations have led to the design of a quick-change system that allows a complete change of the furnace vessel in less than 6 hours. The system has already been implemented in a number of projects.
Ladle pouring machine
In addition to the above, INDUGA will present an innovative ladle pouring machine. Their exhibit will include the associated pouring process automation technology, more specifically the operator desk with the caster control system and the equipment providing camera-based monitoring of the pouring operation.
Three- chamber pouring furnace
From our extensive range of pouring furnaces for diverse applications, INDUGA – an OTTO JUNKER subsidiary – will be exhibiting a pressurized three-chamber pouring furnace serving a horizontal-type continuous caster producing brass billets. The 7.5 tonne pressurized pouring furnace is heated by a channel inductor with a 200 kW power rating located between the pressure chamber and the pouring chamber.