Control Alternatives for Tube Furnaces

Three-Zone Furnace Chamber Control

The temperature is measured by thermocouples positioned outside of the working tube, one in the middle and two on the sides. The outer zones are controlled with a setpoint-offset in relation to the middle zone. This allows the heat loss at the ends of the tube to be compensated to ensure an extended zone of constant temperature (+/- 5 K).

Furnace Chamber Control 
 with temperature measurement in furnace chamber outside the working tube.

• Advantages: Thermocouple protected against damage and aggressive load, very even control, attractive price
• Disadvantage: Temperature difference between displayed temperature on the controller and inside the tube

Extension Package for Furnace Chamber Control

• with additional temperature measurement in the working tube and display of the measured temperature

• Advantages: Very precise and rapid control adjustment
• Disadvantage: Costs

Only the furnace chamber temperature is measured and controlled. Regulation is carried out slowly to avoid out-of-range values. As the charge temperature is not measured and controlled, it may vary a few degrees from the chamber temperature.

If the charge control is switched on, both the charge temperature and furnace chamber temperature are measured. By setting different parameters the heat-up and cooling processes can be individually adapted. This results in a more precise temperature control at the charge.