Control and Documentation Alternatives for Melting Furnaces

Eurotherm 3208 controller

Work platform of K 360/12

Bath control with thermocouple in the melt

Compact controller Eurotherm 3504

Furnace Control with the Eurotherm 3208

In the basic model, Nabertherm melting furnaces are equipped with furnace chamber control using the Eurotherm 3208 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.

Bath Control for Bale-Out and Tilting Crucible Furnaces (Cascade Control)

In the basic version, the bale-out and tilting crucible furnaces of the T.. and K.. product lines 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.

Bath Control with Controller Eurotherm 3504

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.