High-Temperature Sintering Furnace: Working Principle and Components

A high-temperature sintering furnace mainly consists of:

Heating Chamber – Constructed from refractory materials such as silicon carbide, magnesium oxide, and aluminum oxide.
Electric Heating Element – Typically made of nickel-chromium alloy wire.
Furnace Body – The exterior is made of iron sheets, often coated with wrinkle paint for insulation and durability.
Furnace Door – Equipped with a small observation window containing a transparent mica sheet to monitor internal conditions.
Automatic Temperature Controller – Ensures precise temperature regulation during the sintering process.
Thermocouple – Measures furnace temperature accurately.

The furnace door is closed during operation, and opening/closing is convenient.
The automatic temperature controller is based on a vacuum tube high-frequency oscillation circuit. A storage coil is coupled appropriately to fix the oscillation frequency.
The storage coil, together with the thermocouple, provides an accurate temperature reading. A small metal flag on the pointer indicates when the desired temperature is reached.

How temperature control works:

When the furnace reaches the set temperature, the coupling between the flag and storage coil stops the oscillation. This changes the polarity of the tube’s current, triggering a relay that cuts off the heating element’s power to prevent further temperature rise.
As the temperature drops, the flag decouples from the storage coil, restoring oscillation and reactivating the relay. This allows the current to resume, gradually reheating the furnace.
This on/off cycling of the current automatically maintains the furnace at the set temperature.

Adjusting temperature during operation:

If the temperature decreases: Turn off the power, move the control knob left to the new set temperature, then reconnect power.
If the temperature increases: Turn the control knob right to the new set temperature. The furnace can then continue to heat to the desired level.