EXPLORE Sigma Muffle  FURNACES
Sigma supplies a wide range of laboratory and industrial furnaces with customized designs and options to meet customers’ requirements and budget. Products are ISO, CE certified, global 500 cooperative factory, high level of reliability, exported to more than 40 countries worldwide in the past 3 years.

Sigma Furnace makes your heat treatment more successful!

MUFFLE FURNACES – RFQs & KNOWLEDGEs
WHAT IS A MUFFLE FURNACE?
Muffle furnace is a daily using heat treatment equipment in laboratory and industrial. Features high alumina fiber insulated box type chamber furnace; microprocessor controlled, fast heating and cooling with low energy consumption, volumes up to 96L with max temperature up to 1800°C.

MUFFLE FURNACE CATEGORY
Generally, a muffle furnace can be classified into several categories as bellow:

Firstly, based on Working Temperature ranges: 30-1100°C muffle furnaces, 1200-1400°C muffle furnaces and 1300-1700°C muffle furnaces.
Secondly, based on Constructed Structures: Chamber Furnace, Tube Furnace, Pit Type Furnace, Benchtop / table top furnace etc.
Thirdly, based on Heat Treatment Processes: Standard Muffle furnaces (heat treatment in air), Atmosphere Muffle Furnaces, Vacuum Muffle Furnaces etc
MUFFLE FURNACE STRUCTURE & CONFIGURATIONS
Muffle furnace is consist of a outer dual-layer steel sheel, an inner high alumina insulation chamber, a set of heating elements and temperature control etc.

Outer shell: Dual-layer steel case coated with environmental powder, which makes long service life and keeps shell surface safe to touch; Furnace top could be equipped an exhaust device in case any corrosive gases emitted during the heating. Ceramic Insulated doors with hinges and door locks open sideway, and there can be a watching window design on the door center if needed.
Insulation chamber: muffle furnace chamber is built with multi-layer high alumina ceramic fiber board, low density and high insulation capacity, insulation on all sides to avoid heat loss and makes temperature resistant up to 1800 degree C.
Heating elements: Heating resistance coil wire (HRE) used in RT-1250 degree C Muffle furnace, Silicon carbide (SIC) heating Element used in 1200-1450 degree Muffle furnace, molybdenum Disilicide (MoSi2) U shape rod for 1800 degree Muffle furnace.
Temperature control: Sigma Muffle Furnaces adopt top brand Shimaden or Eurotherm, which is a digital microprocessor-based profile PID controller with accurate and programmable temperature settings with SV and PV display. (PLC with visable heating curves are available). The programmable controller displays RAMP rate and soaking time for better understanding. Ramp Rate is the Change of temperature per unit of time. And heating rate could be adjustable freely based on heat treatment processes. We suggest muffle furnaces with HRE or SiC heating element, Max heating rate no more than 25°C per minute, while MoSi2 furnace no more than 10°C per minute.
WHAT IS APPLICATION RANGES FOR A MUFFLE FURNACE?
Muffle furnaces are suitable for an extensive range of heat treatment applications such as annealing, tempering, hardening / quenching, calcination, carbon nanotube production, ashing, LOI analysis, sintering etc. in labs and various industries, including:

Cement, building materials industries: thermal processing or processing of small workpieces.
Pharmaceutical industry: drug testing, pretreatment of medical samples, etc.
Analytical chemical industry: sample processing in water quality analysis, environmental analysis and other fields. It can also be used for petroleum and its analysis.
Coal quality analysis: measure moisture, ash content, volatile matter, ash melting point analysis, ash component analysis, and elemental analysis as well as general-purpose ashing furnace.
HOW TO CHOOSE A MUFFLE FURNACE?
Choosing a right muffle furnace is important to your heat treatments performance. It will help you make the right choice by following the bellow suggestions:

Confirm working temperature range firstly: generally, a muffle furnace classified into three categories based on its working temperatures, namely 30-1100°C, 1200-1300°C, 1400-1800°C. Therefore, it is important to know the actual working temperature of the loaded materials (soft point or melting point), for it affects the heat treatment results much. In addition, price and furnace structures differs much among temperature ranges
Needed chamber size with depth, width, height: A suitable working space will improve the heating performance and cost less
Kind of processed materials: The processed materials affect the furnace configurations. For example, heated samples generated with corrosive gases during the heating should equip an exhaust system
Furnace chamber working conditions: Sometimes, the processed conditions affect the furnace structure. For example, protective gases or vacuum pumping requires an atmosphere furnace or tube furnace, while a standard muffle furnace will not be competent

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