The application of alternative heating technologies depends on the requirements for melt quality, productivity and energy efficiency. In principle either electrically or gas-fired furnaces can be used. In this context, with respect to costs the local pricing for the alternative energy play a decisive role.

Gas-fired furnaces are ideal for melting, particularly if equipped with exhaust gas discharge over the crucible edge. Side exhaust gas discharge is best if a high melt quality is required. However, a higher melt quality means a lower energy efficiency since a fuel-fired furnace with side exhaust gas discharge consumes approx. 20-25 % more energy than a furnace with an exhaust gas discharge over the crucible edge.

Fuel-fired furnaces provide for optimal energy efficiency in combination with highest melt quality due to their burner system that includes heat recovery via recuperator. The hot exhaust gases from the furnace preheat the combustion air for the burner via a heat exchanger. This system leads to savings of up to 25 % compared to conventional fuel-fired furnaces with a side exhaust gas discharge.

If the melt quality and energy efficiency take priority, an electrically heated furnace is the best choice. The heating is controlled very steadily and precisely. The melt is not polluted through immissions from a fuel-fired heating. Electrically heated furnaces can achieve up to 85 % of the melting performance of fuel-fired furnaces with a side exhaust gas discharge. If the furnaces are used only for holding, we recommend the T…/10 models, which are very energy efficient due to their very good insulation and reduced connected load.

Exhaust gas discharge over the crucible edge is the standard design for our gas and oil-fired furnaces, except for the TB models for furnace temperatures of 1200 °C, since these furnaces are normally used as holding furnaces. Due to the high melting performance, the furnaces are perfectly suited for melting. This type of exhaust gas discharge is characterised as follows:

• Very high melting performance, ideal for use as a melting furnace
• Low power consumption since the crucible is not just heated from the outside but part of the heat also enters the crucible from above. Energy savings of up to 20 % compared to furnaces with a side exhaust gas discharge

• Limitations on the melt quality due to higher burn-off and increased hydrogen absorption by the melt from the exhaust gases
• Bath control not recommended

The side exhaust gas discharge is available for all fuel-fired crucible furnaces. Although the melting performance is not as high as with an exhaust gas discharge over the crucible edge, it provides for better melt quality and, in combination with a bath control, is highly recommended for holding operation.

• High melt quality due to low burn-off and reduced hydrogen inclusions in the melt
• Swing lid-reduction of power consumption up to 50 % during holding with a closed swing lid
• Operator exposed to less heat in the area above the crucible
• Best melt quality if a bath control for precise temperature control is used

• Lower melting performance compared to furnaces with exhaust gas discharge over the crucible edge
• Power consumption during melting around 25 % higher compared to furnaces with exhaust gas discharge over the crucible edge

Fuel-fired furnaces with burner systems that include heat recovery via a recuperator provide for optimum energy efficiency in connection with a top melt quality. The combustion air for the burner is pre-heated with the hot exhaust gases from the furnace via heat exchanger. The system results in savings of up to 25 % compared to conventional fuel-fired furnaces with side exhaust gas discharge.

Depending on the utilisation the relatively higher acquisition costs pay off already after a short period of time.

• Lower melting performance than furnaces with exhaust gas discharge over the crucible edge
• Power consumption during melting around 20-25 % higher than furnaces with exhaust gas discharge over the crucible edge

The gas-fired or oil-heated tilting furnaces in the KB series provide for high melting output, making them ideal for melting operations. The use of high-quality insulation materials results in very low energy consumption. The two-stage burner can be configured for either gas or oil operation. Designed with an exhaust vent over the crucible edge, these models achieve very high melting rates and optimum energy efficiency.

• KB../12 with Tmax of 1200 °C for aluminum and zinc alloys
• KB../14 with Tmax of 1400 °C, suitable for copper alloys with a maximum melting bath temperature of 1300 °C (appropriate in some cases for aluminum)
• Fuel heating with gas or oil
• Two-stage output control: High load for melting operation, low load for holding operation with automatic switching between both modes
• Modern burner system with optimized flame guide: High efficiency provided by over-pressure operation to keep out entrained air
• Gas system consisting of pressure regulator, gas filter, manometer and solenoid valves
• Safe flame monitoring
• Burner technology with easy-to-service design, e.g. flame head can be removed from the rear when the burner is swung out
• Burner technology compliant with DIN 746, Part 2
• Designed for natural gas or liquid natural gas with 8.8 kWh/m3 - 25.9 kWh/m3
• Required gas input pressure: 50 mbar
• Operation with other fuels and/or with another gas input pressure possible
• High melting output powered by high-performance burners and high-quality insulation
• Crucible made of isostatically pressed clay-graphite
• Electro-hydraulic tilting system with flame resistant HFCE hydraulic fluid
• Safe, uniform and precise pouring enabled by the optimum pivot point of the furnace and the manual operation of the slider valve
• Multi-layered insulation with lightweight refractory bricks provide the furnace chamber lining, 1400 °C models come with an additional wear-and-tear layer made of copper-resistant refractory concrete
• Emergency outlet for safe discharge of the melt in case of a crucible break
• Exhaust gas discharge over the crucible edge, resulting in approx. 20 % more melting output compared to side exhaust discharge, design without swing lid
• Over-temperature limiter for the furnace chamber with automatic reset to protect against over-temperature. The limit controller switches off the heating when the pre-set limit temperature has been reached and does not switch it on again until the temperature falls below the setting again.
• Furnace chamber control with temperature measurement behind the crucible, recommended when using as pre-melt furnace
• Side-wall exhaust gas vent for KB…/12 models, see additional equipment

Additional equipment

• Side exhaust gas discharge for melt and holding operation
  • Low burn-off provides for high quality melt
  • Low hydrogen absorption by the melt
  • Low heat exposure for the operator in the area above the crucible
  • Swing lid which, when closed during holding operation, saves up to 50 % energy
  • Approx. 20 % lower melting output than for exhaust gas venting over the crucible edge
• Insulated connecting piece (exhaust flue) for side-wall exhaust gas vent to a connected customer suction system
• Exhaust gas collection hood for furnaces featuring exhaust gas venting over the crucible edge
• Work platform or platform for easier charging
• Crucible breakage monitoring with optical and acoustic signal (only for models KB ../12)
• SMS-message to one or more mobile phones in case of crucible breakage. One or more furnaces can be connected to the messaging device in parallel
• Bath control system
  • Furnace control via the bath temperature
  • Thermocouples in the furnace chamber and the melt
  • Improved melt quality ensured by a reduction in temperature overshoots
  • Integrated safety controller system that, in case of bath thermocouple breakage, continues to operate the furnace at a reduced output to prevent the melt from solidifying

The electrically heated tilting furnaces of the K and KF series are characterized by high melting performance with very uniform temperature distribution in the melt. Aluminum and brass can be melted in the 1200 °C version. The 1300 °C version can also be used to melt bronze alloys. For faster heating-up cycles in batch operation furnaces can be insulated with fiber resulting in lower heat storage (KF models).

• K, KF../12 with maximum furnace chamber temperature of 1200 °C for aluminum or brass. Maximum bath temperature, depending on the condition of the crucible, between 1050 °C and 1100 °C
• K, KF../13 with maximum furnace chamber temperature of 1300 °C also suitable for bronze alloys or brass, with a maximum melt temperature of 1200 °C
• Heating from three sides using electric heating elements, radiating freely on carrier tubes, simple exchange of individual heating elements
• Multi-step wiring of the heating elements for furnaces with more than 50 kW electrical rating
• Heating of furnaces up to 24 kW power rating controlled using long-lasting, noiseless solid-state-relays
• Heating of furnaces beyond 24 kW with contactors
• High melting performance with uniform temperature distribution in the melt
• Insulation constructed in multiple layers with lightweight refractory bricks on the hot face (K models)
• Insulation constructed in multiple layers with fiber material in the side walls and corner bricks to support heating elements (KF models)
• Crucible of clay-graphite up to K 240, isostatically pressed clay-graphite or SiC from K, KF 360 and up
• Electro-hydraulic tilting system with flame resistant HFCE hydraulic fluid
• Safe, even, and precise pouring thanks to optimum pivot point in the furnace and manual throttling valve operation
• Emergency outlet for safe draining of the melt in case of crucible breakage
• No exhaust gas discharge needed
• Integrated safety system which continues to operate the furnace at reduced power in case of malfunction in the bath thermocouple, in order to prevent the freezing of the melt
• Over-temperature limiter in furnace chamber for protection against overheating. The limiter switches the heating off when the set limit temperature is reached, and only switches it back on after the temperature has fallen again
• Furnace chamber control with temperature measurement behind the crucible, recommended for melting

Additional equipment

• Work platform for easy charging
• Crucible breakage monitor with visual and audible signal (only for models K, KF ../12)
• SMS-message to one or more mobile phones in case of crucible breakage. One or more furnaces can be connected to the messaging device in parallel
• Bath control with thermocouples in the furnace chamber and in the melt. The furnace temperature is controlled through the melt. Temperature overshoots are reduced, thus the quality of the melt is improved
• Heating system operated through thyristors in phase-¬angle mode provides for even load on the heating elements and results in longer service life
• Multi-step switching of the furnace heat (see page 21). In holding mode, a switch or the controller is used to turn off one heating section in order to reduce the electrical rating
• Higher electrical ratings to increase melting performance

The gas-fired or oil-heated bale-out furnaces of the TB series provide for high melting output. The use of modern burner systems, optimized pressures and flame guide in the furnace as well as the processing of high-quality insulation materials result in very low energy consumption.

The TB ../12 models are largely used for melting and holding of aluminum and zinc alloys, for example in die-cast foundries. The side exhaust gas discharge provides for a high quality melt. The TB 10/14 to TB 40/14 models are mostly used for melting copper alloys in small foundries. This is why these furnaces are equipped with an exhaust gas vent over the crucible edge for high melting output and with a collar plate as a standard which can be swung to the side for pulling the crucible.

• TB../12 with maximum furnace chamber temperature of 1200 °C for aluminum and zinc alloys
• TB../14 with maximum furnace chamber temperature of 1400 °C, suitable for copper alloys with a maximum melting bath temperature of 1300 °C (appropriate in some cases for aluminum)
• Fuel heating with gas or oil
• Two-stage output control: High load for melting operation, low load for holding operation with automatic switching between both modes
• Modern burner system with optimized flame guide: High efficiency provided by over-pressure operation to keep out entrained air
• Gas system consisting of pressure regulator, gas filter, manometer and solenoid valves
• Safe flame monitoring
• Burner technology with easy-to-service design, e.g. flame head can be removed from the rear when the burner is swung out
• Burner technology compliant with DIN 746, Part 2
• Designed for natural gas or liquid natural gas with 8.8 kWh/m³ - 25.9 kWh/m³
• Required gas input pressure 50 mbar
• Operation with other fuels and/or with another gas input pressure possible
• High melting output powered by high-performance burners and high-quality insulation
• Multi-layered insulation with lightweight refractory bricks provide the furnace chamber lining, 1400 °C models come with an additional wear-and-tear layer made of copper-resistant refractory concrete
• Emergency outlet for safe discharge of the melt in case of a crucible break
• Exhaust gas discharge Exhaust gas discharge options, see page 6
  • Exhaust gas discharge over the crucible edge TB…/14 models, resulting in approx. 20% more melting output compared side exhaust discharge, design without swing lid
  • Side-wall exhaust gas vent for TB…/12 models (for description, see additional equipment)
• Crucible pulling device with swinging collar plate for models to TB 10/14 - TB 40/14
• Over-temperature limiter for the furnace chamber with automatic reset to protect against over-temperature. The limit controller switches off the heating when the pre-set limit temperature has been reached and does not switch it on again until the temperature falls below the setting again.
• Furnace chamber control with temperature measurement behind the crucible, recommended when using as pre-melt furnace

Additional equipment

• Side exhaust gas discharge (for 1400 °C models)
  • Low burn-off provides for high quality melt
  • Low hydrogen absorption by the melt
  • Low heat exposure for the operator in the area above the crucible
  • Swing lid which saves energy when closed
  • Approx. 20% lower melting output than for exhaust gas venting over the crucible edge
• Insulated connecting piece (exhaust flue) for side-wall exhaust gas vent to a connected customer suction system
• Exhaust gas collection hood for furnaces featuring exhaust gas venting over the crucible edge
• Work platform or platform for easier charging
• Crucible breakage monitoring with optical and acoustic signal (only for models KB ../12)
• SMS-message to one or more mobile phones in case of crucible breakage. One or more furnaces can be connected to the messaging device in parallel
• Bath control system (only for 1200 °C models)
  • Furnace control via the bath temperature
  • Thermocouples in the furnace chamber and the melt
  • Improved melt quality ensured by a reduction in temperature overshoots
  • Integrated safety controller system that, in case of bath thermocouple breakage, continues to operate the furnace at a reduced output to prevent the melt from solidifying
• Crucible pulling device with swinging collar plate for models to TB 20

The fuel-heated melting furnaces in the TBR and KBR series fitted with the side exhaust gas discharge provide for optimum energy utilization combined with highest quality melt. Fitted with a burner system including heat-recovery system using a recuperative burner, the energy efficiency of ordinary fuel-heated melting furnaces is significantly improved.

Depending on utilization the hot exhaust gases from the furnace are guided through a heat exchanger in order to preheat the combustion air for the burner. The system provides for energy savings of up to 25 % compared to ordinary fuel-heated furnaces with side exhaust gas discharge. The higher purchase costs are amortized within a short time.

• Tmax 1100 °C for aluminum and zinc alloys
• Two-stage output control: High load for melting operation, low load for holding operation with automatic switching between both modes
• Modern burner system with optimized flame guide: High efficiency provided by over-pressure operation to keep out entrained air
• Heat exchanger in the exhaust gas duct to preheat the combustion air for the burners
• Energy savings of up to 25% in comparison to other fuel-heated melting furnaces featuring side-wall exhaust gas vents
• Gas system consisting of pressure regulator, gas filter, manometer and solenoid valves
• Safe flame monitoring
• Burner technology with easy-to-service design, compliant with DIN 746, Part 2
• Designed for natural gas or liquid natural gas with 8.8 kWh/m3 - 25.9 kWh/m3
• Required gas input pressure 70 mbar
• Operation with other fuels and/or with another gas input pressure possible
• High melting output powered by high-performance burners and high-quality insulation
• Multi-layered insulation with lightweight refractory bricks provide the furnace chamber lining
• Emergency outlet for safe discharge of the melt in case of a crucible break
• Side exhaust gas discharge
  • Low burn-off provides for high quality melt
  • Low hydrogen absorption by the melt
  • Low heat exposure for the operator in the area above the crucible
• Over-temperature limiter for the furnace chamber with automatic reset to protect against over-temperature. The limit controller switches off the heating when the pre-set limit temperature has been reached and does not switch it on again until the temperature falls below the setting again.
• Furnace chamber control with temperature measurement behind the crucible

Additional standard equipment KBR models

• Electro-hydraulic tilting system with flame resistant HFCE hydraulic fluid
• Safe, uniform and precise pouring enabled by the optimum pivot point of the furnace and the manual operation of the slider valve of the hydraulic system
• Crucible is standard

Additional equipment for all models

• Crucible made of clay-graphite
• Work platform or platform for easier charging
• Crucible break monitoring with optical and acoustic signal
• Bath control system
  • Furnace control via the bath temperature
  • Thermocouples in the furnace chamber and the melt
  • Improved melt quality ensured by a reduction in temperature overshoots
  • Integrated safety controller system that, in case of bath thermocouple breakage, continues to operate the furnace at a reduced output to prevent the melt from solidifying

Due to their high-grade insulation and optimized connected loads the models T and TF can be used both for melting and holding. They feature good melting output together with outstanding temperature uniformity in the melt. The 1100 °C version can be used for melting aluminum, the 1200 °C version for brass as well. The 1300 °C version can also be used for melting bronze alloys.

The T models are fitted with multi-layer insulation. The furnace chamber insulation with high-quality lightweight refractory bricks is recommended for holding operation. For rapid heat-up times in non-continuous operation, the TF models can also be used, which are lined with a fiber insulation with low heat retention capacity.

• T, TF../11 with maximum furnace chamber temperature of 1100 °C for aluminum or zinc. Maximum melt temperatures, depending on the condition of the crucible, between 950 °C and 980 °C
• T, TF../12 with maximum furnace chamber temperature of 1200 °C also suitable for brass. Maximum melt temperatures, depending on the condition of the crucible, between 1050 °C and 1100 °C
• T, TF../13 with maximum furnace chamber temperature of 1300 °C, also suitable for bronze alloys. Maximum melt temperatures, depending on the condition of the crucible, between 1150 °C and 1200 °C
• Four-side heating using electric heating elements, freely radiating on carrier tubes
• Simple replacement of individual heating elements. In case of crucible breakage, only the defective heating elements on each level need to be replaced
• Heating of furnaces up to 60 kW power rating controlled using long-lasting, noiseless solid-state-relays
• Heating of furnaces beyond 60 kW with contactors
• High melting performance with uniform temperature distribution in the melt
• Insulation constructed in multiple layers with lightweight refractory bricks on the hot face (T models)
• Insulation constructed in multiple layers with fiber material in the side walls and corner bricks to support heating elements (TF models)
• Emergency outlet for safe draining of the melt in case of crucible breakage
• No exhaust gas discharge needed
• Integrated safety system which continues to operate the furnace at reduced power in case of malfunction in the bath thermocouple, in order to prevent the freezing of the melt
• Over-temperature limiter in furnace chamber for protection against overheating. The limiter switches the heating off when the set limit temperature is reached, and only switches it back on after the temperature has fallen again
• Furnace chamber control with temperature measurement behind the crucible, recommended for melting
• Crucible not included in the standard version

Additional equipment

• Crucible of clay-graphite or SiC
• Work platform
• Crucible breakage monitor with visual and audible signal (not for 1300 °C models
• SMS-message to one or more mobile phones in case of crucible breakage. One or more furnaces can be connected to the messaging device in parallel
• Bath control with thermocouples in the furnace chamber and in the melt (not for 1300 °C models). The furnace temperature is controlled through the melt. Temperature overshoots are reduced, thus the quality of the melt is improved
• Heating system operated through thyristors in phase-angle mode assures an even charging of heating elements
• Multi-step switching of the furnace heat (see page 23). In holding mode, a switch or the controller is used to turn off one heating section in order to reduce the electrical rating
• Higher electrical ratings to increase melting performance

The electrically heated tilting and bale-out furnaces of the KC and TC series are characterized by a higher melting performance than achievable with wire heated melting furnaces. These furnaces are designed for permanent operation at working temperatures.

• Tmax 1400 °C, also suitable for bronze alloys with a maximum melt temperature of up to 1320 °C, subject to the condition of crucible
• Heating from two sides by generously dimensioned SiC rods, uniform temperature distribution
• Simple exchange of individual heating elements
• Heat operation by thyistors in phase-angle mode with performance control: The resistance of the SiC rods changes with temperature and age. Performance control ensures constant power of heating irrespective to the condition of the heating elements.
• High melting performance with uniform temperature distribution
• Insulation constructed in multiple layers with lightweight refractory bricks on the hot face
• SiC-Crucible
• Electro-hydraulic tilting system with flame resistant HFCE hydraulic fluid (KC models)
• Safe, even, and precise pouring thanks to optimum pivot point in the furnace and manual throttling valve operation (KC models)
• Emergency outlet for safe draining of the melt in case of crucible breakage
• No exhaust gas discharge needed
• Integrated safety system which continues to operate the furnace at reduced power in case of malfunction in the bath thermocouple, in order to prevent the freezing of the melt
• Over-temperature limiter in furnace chamber for protection against overheating. The limiter switches the heating off when the set limit temperature is reached, and only switches it back on after the temperature has fallen again
• Furnace chamber control with temperature measurement behind the crucible, recommended for melting

Additional equipment

• Work platform for simplified loading

The perfect insulation and the reduced electric connected loads provide for perfect energy efficiency and make the T ../10 models optimally suitable for holding operation. Due to the reduced connected load these furnaces are only suitable for melting to a limited extent. This is why they are mostly used in foundries with central pre-melting furnaces followed by transportation of the melt to the holding furnace.

• Tmax 1000 °C, ideally suited for the holding of aluminum
• Four-side heating using electric heating elements, freely radiating on carrier tubes
• Simple replacement of individual heating elements. In case of crucible breakage, only the defective heating elements on each level need to be replaced
• Heating of furnaces up to 60 kW power rating controlled using long-lasting, noiseless solid-state-relays
• Heating of furnaces beyond 60 kW with contactors
• Particularly good insulation constructed in multiple layers with lightweight refractory bricks on the hot face Emergency outlet for safe draining of the melt in case of crucible breakage
• No exhaust gas discharge needed
• Crucible not included in the standard version
• Integrated safety system which continues to operate the furnace at reduced power in case of malfunction in the bath thermocouple, in order to prevent the freezing of the melt
• Over-temperature limiter in furnace chamber for protection against overheating. The limiter switches the heating off when the set limit temperature is reached, and only switches it back on after the temperature has fallen again.
• Furnace chamber control with temperature measurement behind the crucible, recommended for melting
• Additional equipment, see T, TF furnaces

The bale-out furnaces of the TM series were developed especially for use at different pouring locations. The cylindrical, very stable furnace housing, the very high-quality insulation and the meandering heating elements are the special features of this furnace family. The furnaces are designed to be transported by forklift truck and come with a plug-in connection to the control gear. With a forklift truck the furnace can be transported to the pre-melt furnace for filling. When additional switchgear and control boxes are used, the furnace can also be optionally used at different pouring locations.

• Tmax 1000 °C, ideal for holding of aluminum
• Cylindrical, highly stable furnace housing
• Slots under the furnace for safe forklift transportation of the furnace inside the foundry
• All-round heating provided by resistant meandering heating elements
• Switchgear and control box for plug-in connection
• Heating of furnaces up to 60 kW power rating controlled using long-lasting, noiseless solid-state-relays
• Heating of furnaces beyond 60 kW with contactors
• Especially good insulation, multi-layered with fiber material in the furnace chamber
• Emergency outlet for safe discharge of the melt in case of a crucible break
• No exhaust gas vent necessary
• Crucible in standard design not included
• Furnace chamber control with temperature measurement behind the crucible
• Over-temperature limiter in the furnace chamber to protect against over-temperature The limit controller switches off the heating when the pre-set limit temperature setting has been reached and does not switch it on again until the temperature falls below the setting again.

In standard version, Nabertherm crucible furnaces are built with a collar plate fixed to the furnace. The bale-out is done manually or by robot. As additional equipment, the smaller models up to T 40 can be equipped with a swinging collar plate which allows crucible pulling. To pull the crucible, the collar plate is swung to the side, so that the operator has free access to the crucible from above.

The Crucible furnaces of the T.. Series can be equipped with an optional pneumatic lid opener. The pneumatic lid opener is activated by depressing a foot pedal. Optionally, the pneumatic lid opener can be controlled and triggered by an external signal to fully automate the ladling process. The furnace lid swings to the side and the operator has free access to the crucible. This practical feature increases energy efficiency because the furnace is only open during charging and bale-out. Over 50% energy savings can be realized with the pneumatic lid opener vs. an always open furnace (see tables for energy consumption for each model of melting furnace, page 7).

The charging funnel made of stainless steel 1.4301 (304) makes charging the furnace much easier, especially when melting ingots. Long ingots can also be charged extending over the crucible edge, and then sink, guided, into the crucible. Furnaces which are designed with a control system with night-time reduction can, for example, be filled in the evening and, on the following morning a complete melt is ready for use. The funnel is suitable for all melting furnaces, electrically heated or gas- with a side exhaust gas discharge.

For bale-out and tilting furnaces, customized work platforms for charging and servicing can be provided as additional equipment. This feature is used to simplify access to the furnace, particularly for larger furnace models. The operator has access to the top of the furnace to charge ingots or clean the melt.

Nabertherm melting furnaces are equipped with emergency outlet. In case of crucible breakage or leaking melt the crucible breakage alarm device will provide for a warning as soon as fluid metal emerges from the emergency outlet. The warning signal of the alarm is both optical, with an signal lamp, and acoustic, using a horn. As additional equipment it is possible to send an alarm as SMS-message to one or more mobile phones. One or more furnaces can be connected to the messaging device in parallel.

When crucible furnaces are used in continuous operation, it can be necessary to monitor the filling level of the crucible and provide for a signal when defined levels are reached. The signal can be either optical, acoustic, or a signal for automatic filling of the crucible. When the minimum level is reached, a signal to fill a crucible is given. On reaching the maximum level this process is stopped. The measurement of fill level can either be done by using a scale under the furnace or by using a measurement probe to detect the fill level and which records the data very precisely independent from external influences.

For melting furnaces with only furnace chamber temperature control, a separate bath temperature measurement device can be used to check the bath temperature. The measurement device is suitable for a temperature range from 0 to 1300 °C, and can be delivered with different dip pipe lengths (200, 380, 610 mm). Temperature measurement is carried out using a NiCr-Ni thermocouple. The submersion length of the pipe whould be 2/3 of the element length to achieve the most ideal reaction time. The average reaction time is 40 seconds. The thermocouple is suitable for all nonferrous metals except phosphor bronze.

A multi-step switch switches off a part of the heating depending on the power of the corresponding furnace model. Generally, the furnace can be operated at full load for melting. If the furnace is only used in holding mode the connected rating of the furnace can be reduced by turning off a defined part of the heating capacity, resulting in a significant cost advantage. As an option, this function can be automatically switched depending on temperature.

If several crucible furnaces are used the installation of an intelligent power management can be the right choice. Monitoring all furnaces the power management is continuously reconciling the switch-on times of the heating. This effectively prevents all furnaces from switching-on at the same time. The positive impact is that the total connected rating provided by the energy provider can be significantly reduced.

The switchgear of our furnaces is designed for environment temperatures of up to 40 °C. To secure a failure-free and long lasting operation of the switchgear in case of higher temperatures they can be equipped with active fan cooling or even with an air-conditioner.

In the basic model, Nabertherm melting furnaces are equipped with furnace chamber control using the Eurotherm 2208 controller. The temperature is measured in the furnace chamber behind the crucible. Two set values and a heat-up ramp rate may be entered. For example, the set values could be the pouring temperature and the lower idle temperature. Optionally, a 7-day digital timer can be fitted to automatically switch between the two temperatures and different switching times can be selected for each working day.

In the basic version, the bale-out and tilting crucible furnaces of the T.. and K.. series are equipped with with a thermocouple in the furnace chamber behind the crucible. To achieve fast heat-up times the temperature is set significantly higher than the desired bath temperature. Therefore, this control allows very fast heating-up times, but results in considerable temperature overshoots in the melt due to the indirect temperature measurement.

As an option these furnaces can be equipped with a bath control system, which is particularly well-suited for holding operations. A second thermocouple in the bath is used in addition to the furnace chamber thermocouple to measure the bath temperature. Both temperatures are reconciled by the controller. The bath temperature is the target parameter and the chamber temperature is the working tool. This control system significantly improves the melt quality because overshoots can be effectively prevented. As an alternative to the thermocouple in the melt, a thermocouple in a special pocket in the crucible wall can be used (a special crucible with pocket is required) which measures the temperature of the crucible wall. Of course, this indirect control is not as precise as a measurement in the melt. However, the thermocouple is positioned in a protected location.

All melting furnaces can be fitted with an optional bath control system. Instead of only being monitored by a thermocouple behind the crucible, the temperature is also measured in the melt, respectively in the pocket of the crucible wall, (see also description on page 23). Furnaces already in use can also be upgraded with a bath control system. An optional digital seven-day timer which automatically switches between two temperatures can also be added. The two alternate times can be selected for each working day. This allows the bath temperature, for example, to be lowered at night to save energy.

• Alternative operation modes with furnace chamber control of bath control via cascade
• Multi-line and plain text display
• Data entering by using function keys
• Programming the furnace operation with two set values (second temperature, e.g. for night-time temperature reduction)
• A separate, freely programmable preparation program, e.g. to dry the crucible. An external switch is used to switch over to the preparation program.

Additional equipment

• Seven-day timer for switching between two temperatures (e.g. night-time reduction). Switching times can be separately selected for each working day.

The H 700 PLC features state-of-the-art bath control. It provides a combination of precise control, ease of operation and a wide variety of user applications and professional documentation. A touch panel using plain text provides a simple and clean user interface for programming and control.

• Furnace chamber control or alternatively bath control via cascade applicable
• Colored graphic display of all temperatures
• Touch panel provides a simple and clean user interface
• Seven day timer for temperature switching
• For each weekday, a program can be configured with 12 segments
• A separate, user-entered furnace preparation program that can be used to dry the crucible, etc. Access to the program is controlled by a key switch
• Customer can switch between different languages

Addtional equipment for H 700

• Manual Overriding of automatic control
  • If a running program needs to be extended (for example, when working overtime to meet a customer‘s schedule), a key switch can be used to put the programmer into Manual mode in order to continue working at the present temperature. In the background, the original program is continued, and when the key switch is turned back to Program mode, the furnace resumes its currently scheduled set point.
• Documentation of melting process
  • The H 700 controls can be upgraded with the Nabertherm Control Center package (NCC) on a personal computer. NCC controls provide for a professional documentation of the melting process among others, with the following features:
  • All relevant data, such as furnace chamber temperature, bath temperature, messages, etc. are always automatically stored as a daily file.
  • The switchgear is equipped with start and stop buttons. By pressing these buttons, the bath temperature is documented and stored as a file. For instance, customer batches can be monitored and archived separately.

Additional Equipment for all Controllers

• Temporary overriding of bath control to increase melting performance
  • When an empty crucible is recharged, the values measured by the bath thermocouple do not correspond to the actual temperature of the solid metal. Using melt bath regulation in this case would reduce the power available to melt the metal. A pushbutton on the panel allows the operator to temporarily bypass normal control, and have the controller maintain a higher than normal chamber temperature to melt the metal faster. A user-set timer (up to 120 minutes) and set point allows the operator to optimize the time it takes to melt. When the timer elapses, the controller resumes its normal control mode.

Depending on the material flow and space requirements in a foundry, the charging height and pouring height may need to be different for a tilting furnace. For instance, if loading is performed at ground level and the metal is poured into a machine at a higher level, then an optional electro-hydraulic lifting platform can adjust for the difference. The operation of the lifting platform is by means of a 2 hand operation with a manual throttling valve. It can also be interlocked with other machinery and be automatically operated.

Especially in smaller foundries or in foundries with narrow space availability, our TRP 240/S combi transport pan is available. It combines a melting furnace and a transport ladle in one unit. Its electrical connected rating allows the furnace to be used for melting.

• Tmax 900 °C for melting and holding of aluminum
• Electrically heated
• Connection between switchgear and furnace pluggable
• Customer must provide plant crane
• Comfortable planetary gearbox
• Simple handling and precise pouring
• Optimally arranged heating modules resulting in very long crucible standing times

Our melting furnaces in the K, KF, T, and TF series can be upgraded with adapted electrical heating for melting of heavy metals like lead and zinc. The furnace is equipped with a special crucible, in most cases a steel crucible. The melting power is tailored to the type of metal to ensure optimum utilization of the furnace.

For continuous processes, multiple crucible furnaces can be combined on a rotary table system. For example, when using three furnaces with a rotation in 120° steps, loading takes place at the first space, de-gassing at the second space, and bale-out at the third. This ensures a continuous supply of liquid metal at the pouring location. The rotary table is designed with an emergency drain below in case of crucible breakage.

The B 120 - B 500 bath furnaces (without crucibles) have been especially developed for stationary holding operation in die-cast foundries with removal of the melt by a bale-out robot. The tub of the furnace is lined with special long-life brick. The multi-layered backing insulation is designed for lowest electric connected load. The furnace tub is divided into three interconnected chambers. The heating proceeds from the lid into the center chamber. The bale-out openings are dimensioned to enable the robot to be optimally used. In holding operation bath furnaces, when used properly, provide better energy efficiency than crucible bale-out furnaces.

For a variety of projects, Nabertherm has supplied melting furnaces to be upgraded by the customer for the melting of magnesium. Nabertherm supplied the furnace with all necessary control systems and the steel crucible. The furnaces were completed by the customer with the safety devices, pump systems for bale-out, and protective-gas systems. We are capable of implementing furnace systems to provide for a crucible volume of 1500 liters of magnesium.

These compact melting furnaces for the melting of non-ferrous metals and alloys are one of a kind and have a number of technical advantages. Designed as tabletop models, they can be used for many laboratory applications. The practical counter balanced hinge with shock absorbers and the spout (not for KC) on the front of the furnace make exact dosing easy when pouring the melt. The furnaces are available for furnace chamber temperatures of 1000, 1300, or 1500 °C. This corresponds to melt temperatures of about 80-110 °C lower.

• Tmax 1000 °C, 1300 °C, or 1500 °C, with melt temperature about 80 - 110 °C lower
• Crucible sizes of 1, 2, or 4 liters
• Crucible with integrated pouring spout of iso-graphite included with delivery
• Spout (not for KC), mounted at the furnace for exact pouring
• Compact bench-top design, simple emptying of crucible by tiltiing system with gas damper
• Crucible for heating of furnace insulated with a hinged lid, lid opened when pouring

Additional equipment

• Other crucible types available, e.g. steel or SiC
• Design as crucible furnace without tilting device, e.g. for lead melting
• Over-temperature limiter for the furnace chamber with automatic reset to protect against over-temperature. The limit controller switches off the heating when the pre-set limit temperature has been reached and does not switch it on again until the temperature falls below the setting again.
• Observation hole for melt