Induction Heating Systems for Precise Zone Heating & Temperature Control

Many heating processes and applications require precise heating and temperature control of multiple zones. Induction heating is frequently used for precise temperature profiling of multiple zone heating. A conventional method for zone heating by induction is to design and fabricate an elaborate induction coil, where the heating coil is profiled in a way that produces different heating patterns in the workpiece. This approach works well for many applications, but it is not practical when an independent zone temperature control is required. In this case, separate coils, controlled by independent power supplies, can be used. But this approach presents certain technical challenges. If the heating coils are too close to each other, they may interfere and the so-called “cross-talk” effect will be present. This may cause unstable or even damaging operating conditions for the induction heating equipment.

UltraFlex Induction heating systems were successfully used in many projects requiring precise temperature control of multiple heated zones across a workpiece or a susceptor. UltraFlex has developed a technology that overcomes these problems and provides a steady and stable operation of multiple coils working in close proximity. The patented UltraFlex SmartPower induction heating technology can be configured to provide up to 4 independently controlled outputs in one cabinet, thus providing precise control of up to 4 heating zones. Independent power supplies and coils can also be used, as shown in the examples below. In these cases, each zone can be turned on and off or independently controlled to achieve varying temperature profiles with excellent repeatability and controllability.

Induction heating for zone heating and control is used across multiple industries – chemical and waste processing, plasma systems, semiconductors, crystal growing, CVD (chemical vapor deposition), materials research, and more.

Benefits of Zone Control Induction Heating

  • Repeatable and precise control of the temperature in each zone
  • Increased energy efficiency, due to individually optimized zones
  • Optimized central control
  • Smaller footprint
  • Extended fixture life

Examples of Zone Controlled Induction Heating

1. Zone Heating of a Metal Strip with Induction 

Eight zones with varying temperatures from 1832 °F to 2912 °F (1000 to 1600 °C)  using 4×10 kW and 4×15 kW/150 kHz induction power supply units, each providing power to independently controlled induction coil.

Zone Heating of Metal Strips
Zone Heating Metal Strip

2. Induction Heating of Stainless Steel Susceptor for Chemicals Processing

Three zones, independently controlled temperatures using 3 of the Ultraflex 15kW/150kHz induction heating power supplies.

zone heating
Three Zone Suceptor

3. Multiple Output SmartPower Induction Heating System for Crystal Growing Zone Heating

Four independently controlled zones using 3 x 25kW/10-60kHz outputs and one 75kW/10-60kHz output.

Multipule output Smartpower Zone Heating

4. Induction Preheating of a Steel Rail in Railroad Installation

Two zones, with independent temperature control, using 2 x 200kW/10kHz induction power supplies.


5. Heating a Barrel with Wastewater

Three heating zones on the OD and one heating the bottom, with independent temperature control, using 3 x 2kW/200 kHz induction power supplies – air cooled.

heating a barrel with nuclear waste water

application evaluation