A resistance furnace or custom annealing oven is a type of industrial oven used for heat treatment processes such as annealing, tempering, and stress relieving of various materials. It consists of a heating chamber, heating elements made of resistance wires, and temperature control devices.
The furnace operates by passing an electric current through the heating elements, which generates heat that is transferred to the material being treated. The temperature of the furnace can be controlled by adjusting the current flowing through the heating elements.
Resistance furnaces are commonly used for the annealing of metals, particularly steel, as well as for other heat treatment processes such as sintering and brazing. Custom annealing ovens are designed to meet the specific needs of a particular application and may include features such as vacuum or controlled atmosphere capabilities, programmable temperature and time controls, and various safety features.
1) Furnace Lining Feature
Furnace lining is an essential component of industrial furnaces and plays a critical role in ensuring the furnace’s longevity and optimal performance. The lining is typically made of high-temperature resistant materials such as refractory bricks, castables, and ceramic fibers. Here are some common features of furnace lining:
- Thermal Insulation: Furnace lining must have excellent thermal insulation properties to maintain the high temperatures required for industrial processes. The lining’s insulating properties can be improved by using materials such as ceramic fibers, high-temperature wool, and refractory brick with low thermal conductivity.
- Wear Resistance: The lining must be able to withstand the constant wear and tear from the heating elements and the materials being processed in the furnace. Refractory materials such as alumina, magnesia, and silica are commonly used for their excellent wear resistance.
- Chemical Resistance: Furnace lining must also be resistant to chemical attacks from the materials being processed. Refractory materials such as zirconia and silicon carbide are known for their excellent chemical resistance.
- Thermal Shock Resistance: The lining must be able to withstand rapid temperature changes without cracking or breaking. Refractory materials such as silicon carbide and alumina have high thermal shock resistance.
- Corrosion Resistance: The lining must be able to resist corrosion from any corrosive gases or liquids produced during the industrial process. Refractory materials such as silicon carbide and zirconia are known for their excellent corrosion resistance.
2) Door Lifting
The door vertically moves up and down with driven force by electric hoist sprocket.
3) Security measure
- Automatic Shut-off Systems: Resistance furnaces and custom annealing ovens are typically equipped with automatic shut-off systems that stop the furnace’s operation in case of an emergency. These systems can be triggered by factors such as abnormal temperature or pressure, power failures, or other safety hazards.
- Emergency Ventilation Systems: They generate high temperatures, and it is important to have proper ventilation to remove exhaust gases and prevent fires. Emergency ventilation systems can be installed to remove hazardous gases from the furnace’s chamber in case of an emergency.
- Safety Interlocks: Safety interlocks are designed to prevent accidental injury by shutting off the furnace’s operation if someone opens the door or tries to access the furnace while it is in operation.
4) The control system
Here are some common features of the control system in resistance furnaces and custom annealing ovens:
- Temperature Control: The control system allows operators to set and monitor the temperature inside the furnace’s chamber. This is typically done using thermocouples or other temperature sensors that provide feedback to the control system. The system can then adjust the heating elements or other parameters to maintain the desired temperature.
- Time Control: The control system also allows operators to set and monitor the amount of time the furnace runs. This is important for ensuring that the materials being processed receive the correct amount of heat treatment.
- Power Control: The control system can adjust the power input to the furnace to control the rate of heating or to maintain a steady temperature.
- Process Control: The control system can also monitor and control other parameters of the industrial process, such as gas flow, pressure, or other environmental factors. This allows operators to customize the furnace’s operation for different materials and processes.
Technology parameters
The technology parameters of resistance furnaces and custom annealing ovens include temperature range, heating rate, chamber size, atmosphere control, control system, and cooling system. These parameters vary depending on the specific application and materials being processed and are critical for ensuring consistent and reliable results in industrial processes.
The characteristics
Here are some of their key characteristics:
- High Temperature Capabilities: Resistance furnaces and custom annealing ovens can achieve high temperatures, ranging from a few hundred degrees Celsius to over 2000 degrees Celsius, depending on the application.
- Precise Temperature Control: These furnaces offer precise temperature control, allowing for consistent and accurate heating of materials.
- Programmable Process Control: They offer programmable process control, which allows for the customization of various parameters, such as temperature, heating rate, and hold time, for specific applications.
- Versatile Atmosphere Control: Resistance furnaces and custom annealing ovens can control the atmosphere inside the chamber, providing a variety of processing atmospheres, such as oxygen, nitrogen, or other gases, to suit the needs of different applications.
- Uniform Heating: They provide uniform heating throughout the chamber, ensuring consistent and reliable processing of materials.