High Temperature Muffle (Retort) Furnaces

The defining characteristic of a muffle furnace is that it separates the object to be heated from all by products of combustion from the heat source. With modern electrical furnaces, this means heat is applied to a chamber through induction or convection by a high-temperature heating coil inside an insulated material. The insulating material effectively acts as a muffle, preventing heat from escaping. A well-built muffle furnace can reach extremely high temperatures with a high degree of uniformity and accuracy, while preserving the purity of the chamber environment.

What is the difference between a Muffle Furnace and a Retort Furnace?
The difference is largely historical and semantic. A retort is simply the airtight vessel that the material to be processed is placed in. The term comes from the chemical industry. A Muffle furnace refers to the insulation and separation of the heating elements from the contents of the retort. “Muffle Furnace” is terminology that came from the furnace manufacturers, but they both describe the same exact type of furnace.
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Muffle Furnace Design Uses

Muffle furnaces by CM Furnaces come in all form factors, sizes, and temperature ranges. They can use a variety of atmospheres and are offered at a wide variety of price points. Users of the CM series of Muffle Furnaces include:

  • US National Laboratories like Los Alamos, Oak Ridge & Savanna River national labs and many others.
  • Both Government and private research facilities.
  • University science laboratories.
  • Preproduction manufacturing test.
  • Small scale production environments.

CM furnaces has been making muffle furnaces for over 60 years, and built our reputation by providing the most reliable and long lasting furnaces available today. All of our furnaces provide advanced features and a “no-shortcuts” design mindset making them at the uppermost level of the quality spectrum amongst all muffle furnaces manufactured today.

All our Muffle Furnaces feature:

  • Fully programmable control of heating and cooling rates.
  • Highly uniform temperature control.
  • Highly reliable designs use only premium components. Our design emphasis is long life.
  • Extra sturdy construction for long term use.

In most models, both horizontal and vertical models are available for virtually any requirement in single or multi-zone configurations. Custom designs including tilting and rotating systems, atmosphere and vacuum packages, and specialized control systems are offered. Our muffle furnaces can incorporate a graded insulation package using high purity alumina fiber. These furnaces will not hot spot at high temperatures and are resistant to degradation. The rugged steel shell is hinged for easy access inside the furnaces. When you feel the weight of our door, you’ll fully understand you’re in the presence of quality.

CM Muffle Furnaces At A Glance

The following table summarizes our family of muffle furnaces and how to choose between them.

Furnace Type Temperature Range Atmosphere Package* Model
 Box Up to 1200°C (2192°F) Air, Inert, Hydrogen 1200
 Box  Up to 1700°C (3100°F) Inert, Hydrogen 1500
 Box  Up to 1600°C (2900°F) Air, Inert,Oxygen 1600
 Box  Up to 1700°C (3100°F) Air, Inert,Oxygen 1700
 Box  Up to 1800°C (3272°F) Air, Inert,Oxygen 1800
 Box  Up to 1800°C (3272°F) Inert, Hydrogen, H/N2 300 Series

Why Muffle Furnaces by CM Furnace

Serious processing of expensive parts, requires a serious furnace. In our experience the offshore built furnaces resold by our competitors fail to have the uniformity or longevity needed for serious process control. Despite this focus on quality and performance, CM furnaces have what is arguably the best value proposition in the industry.

  • Ease of maintenance – Our modular plate heating elements are among the longest lasting in the industry
  • All Steel construction always has been, always will be.
  • Double Shell Construction
  • High Purity Alumina Fiber Insulation
  • High Quality Molydisilicide Heating Elements
  • Cubed Chamber for Best Uniformity
  • Fan Cooling of Element Terminals
  • Type “B” Thermocouples
  • Independent Over-temperature monitoring and control.
  • Programmable Ramp and Soak Control
  • Phase Angle-Fire SCR Power Controller

And more.

To discuss your needs with one of our production furnace experts, call us directly at (973) 338-6500