How to choose a large furnace production type muffle furnace?

When choosing a large furnace production type muffle furnace, it is necessary to comprehensively evaluate the core dimensions such as furnace size, temperature control, heating elements, furnace structure, atmosphere control, and safety performance to ensure that the equipment meets production needs and has long-term stability. Let’s take a detailed look below!

The commonly used muffle furnace in Kejia electric furnace (click on the image to view product details)

1. Furnace size and capacity
Match production needs
Select the effective furnace size (length x width x height) based on the dimensions of the workpiece (such as length, diameter, height) and batch size, ensuring that the workpiece can be freely placed with a margin of 10% -20% (to avoid uneven thermal field).
Example: If a bar with a diameter of 300mm and a length of 1000mm needs to be processed, the furnace size is recommended to be ≥ 400mm × 500mm × 1200mm.
Batch production: It is necessary to consider the single furnace loading capacity, for example, ceramic sintering requires multi-layer rack design, and the furnace height needs to reserve space.

Furnace material
Refractory materials: High purity alumina fibers or lightweight mullite bricks are preferred, with high temperature resistance (≥ 1600 ℃) and good insulation performance, which can reduce energy consumption.
Furnace structure: Modular design facilitates maintenance, and the all fiber furnace heats up faster than traditional brick furnaces.

2. Temperature control and uniformity
Temperature Control System
Accuracy requirement: The production type muffle furnace requires a precision of ± 1 ℃ or higher, using a PID intelligent temperature controller that supports multi-stage program heating (such as segmented control of heating, insulation, and cooling).
Sensor type: N-type thermocouple (≤ 1200 ℃) or S-type thermocouple (＞ 1200 ℃) to ensure accurate temperature measurement.
Over temperature protection: independent over temperature alarm and power-off function to prevent equipment damage.

thermal field uniformity
Heating element layout: U-shaped or W-shaped silicon molybdenum rods/silicon carbon rods are evenly distributed on both sides of the furnace to avoid local overheating.
Circulating fan: Optional forced air circulation system can be used to improve the temperature uniformity inside the furnace (within ± 5 ℃), especially suitable for large-sized furnaces.

3. Heating element and power
Component Type
Silicon molybdenum rod: suitable for high temperature scenarios between 1400-1700 ℃, with strong oxidation resistance and long lifespan.
Silicon carbon rod: suitable for environments ≤ 1400 ℃, low cost, but prone to aging, requiring regular replacement.
Resistance wire: only suitable for low temperature scenarios ≤ 1200 ℃, with high energy consumption.

4. Furnace structure and design
sealing performance
Double layer furnace shell structure, with refractory material on the inner layer and cold-rolled steel plate on the outer layer, filled with insulation cotton in the middle to reduce heat loss.
The furnace door adopts silicone sealing strips or pneumatic locking devices to ensure sealing under vacuum or protective atmosphere environment.

Operational convenience
Observation window: Optional high-temperature resistant quartz observation window for real-time monitoring of workpiece status.
Furnace door design: Side opening or upward opening furnace doors should be equipped with safety limit switches to prevent accidental opening.
Data interface: Supports RS485/USB interface, making it easy to connect to a computer to record temperature curves.

5. Atmosphere control (optional)
Protecting the Atmosphere
If inert gases (such as nitrogen and argon) are required for protection, gas flow meters and pressure gauges need to be installed, and the furnace needs to reserve inlet and outlet ports.
Vacuum function: Optional mechanical pump or molecular pump can be used to achieve a vacuum degree of ≤ 10 ⁻ ² Pa, suitable for degassing or special material processing.

exhaust system
Forced exhaust fan+chimney design, quickly discharging high-temperature exhaust gas to avoid oxidation or pollution inside the furnace.

6. Safety and energy consumption
safety protection
Overcurrent, overvoltage, and leakage protection devices.
The surface temperature of the furnace body should be ≤ 50 ℃ (when the ambient temperature is 25 ℃) to prevent burns.

energy consumption optimization
Variable frequency technology adjusts heating power and reduces standby energy consumption.
The thickness of the insulation layer is ≥ 150mm to reduce heat loss.

Customized industrial box type muffle furnace (click on the picture to view product details)

Based on the comprehensive evaluation of the above dimensions, combined with production demand, budget, and long-term operating costs, a more suitable large furnace production type muffle furnace can be selected.Click to learn more customized muffle furnaces! Or click on online customer service to learn more about product information!