In science laboratories or the metallurgy industry, muffle furnaces are nowadays highly popular as the heat-producing appliance in oxygen-deprived conditions. It is a systematically designed furnace which provides high temperature with its advanced thermal insulation system but with a low level energy consumption. This instrument is composed of a furnace box with many types of applications like calcination, heat treatment etc. This furnace is a metallic chamber and it is coated with refractory material to prevent all kinds of heat loss. Its special instrumentation helps in other chemical processes like annealing, sintering, ashing along with other chemical heat treatments.

Remembering the versatile utilization of muffle furnaces, we have launched various kinds of muffle furnaces producing heats from 900 to 1800 degree Celsius.

Structure of the muffle furnace:

• There is the carcass structured furnace having double walls (Sometimes it comes with triple walled structure). There is zirconia fiberboard cemented from different

• Low density based ceramic fibers are present to provide high-level thermal insulation.

• Mechanical arrangement is present for opening and closure of the door.

Heating elements: Silicon carbide or Molybdenum disilicide are the basic heating elements used in the Muffle furnace. These elements as the U-shaped rod incurs 1450 to 1800 degree celsius. 

Temperature control: There is the microprocessor based PID system to generate accurate and effective temperature within the furnace. It has the display to monitor the ramp rate and the soaking time for effective performance.

Ramp rate: It’s the measurement of time to gauge temperature change per minute. With best ramp rated muffle furnaces, 1000 degree temperature is achievable in 45 to 90 minutes.

Voltage range: Normal voltage range of muffle furnaces varies from 220 to 230 volt AC. When the size of the furnace enhances, the voltage range also enhances. 

Doors: In muffle furnaces, there are insulated doors with the board insulation system. There are hinges with door lock systems. It is designed with heat protection processes. 

Classification of muffle furnaces: 

There are many kinds of muffle furnaces in the laboratory which are box furnace, vacuum furnace, laboratory furnaces, rotary, tube and many others. In these furnaces, working process is the same but structural features are slightly different with variation of applications of heat treatments in laboratories.

Working procedure of high-temperature muffle furnace? 

In this muffle furnace, heat is mainly developed by the heat-resistant electronic elements. Door safety switch is present in the muffle furnace to protect the instrument from the heat shock. In this heat treatment, there is the PID controller system which enhances or lessens the heat supply to the machine. In the LED display, the machine displays the temperature supply.

Safety measures during muffle furnace usage:

• The cooling rate of the muffle furnace of 1400 and 1800 degrees should not be more than 5 degree celsius.

• Users should not open the muffle furnace door above 400 degree celsius. Otherwise, it may cause thermal shock.

• Users should not use any kinds of toxic gas or chemical ingredients within the muffle furnace. It may create damage to the machines.

• Users may observe some cracks on the external surface of the chamber due to overuse. Aluminum coating is the best way to repair such damages.

• Users should put a refractory door block to avoid heat loss.

Special notes about muffle furnace heat machines: 

• Most of the middle furnace producing companies offer 8 to 10 years of after sales support.

• Users should be aware that any kinds of corrosive or toxic material related attacks or chamber cracks are not served with the warranty procedure.

Laboratory tests where muffle furnace is mostly used: 

• In metallurgy laboratories, muffle furnaces are highly utilized for stone wire sample firing, plastic stencil sample tests, annealing and other chemical analyses.

• In different kinds of heat treatment such as Gravimetric analysis, ignition tests, atmospheric processing and many others tests provide great results with muffle furnace heat treatment processes.

• Digital single set point temperature
• Ceramic wool insulation permits faster heat-up, reducing energy consumption.
• Equipped with thermocouple break protection, which helps preventing thermocouple failure runway condition