Lab Muffle Furnace
The vital elements of the Muffle furnace are explained as below:
Outer chamber of the muffle furnace is created using mild steel sheet because it has better malleability, weld ability and ductility properties than cast iron along with corrosion resistance. Outer chamber of the muffle furnace has a thick epoxy paint coating to give it an aesthetically desirable appeal and also to induce few more years to the shelf life of the equipment on being operated at elevated temperatures.
Inner chamber of the muffle furnace is made of either pre fabricated ceramic molds or firebricks depending upon the size and temperature requirements of the finished equipment. We use the PID Digital temperature controller cum indicator for its exemplary reputation as immaculate temperature control device. We consider Insulation as the most important factor in working of a muffle furnace and hence extra care is taken while designing this part of the furnace. The insulation being used in our muffle furnace is a combination of ceramic wool and mineral wool because we have engineered and found out that when used in combination they prove to provide better thermal insulation and less heat loss. Our lab muffle furnaces are constructed to generate heat up to 1200°C. Mostly laboratory furnaces are designed to have a working temperature range of 1100°C – 1200°C. The most critical working phenomenon which needs to be taken care of while choosing a laboratory furnace is its maximum working temperature because it needs to be in absolute accordance to the application.
The use of lab muffle furnace in can be explained as its ability to burn off desired organic compounds so as to evaluate the amount of inorganic compounds inside a test materiel.
Laboratory furnaces are referred by various names being relative to the application such as bench type furnaces, chamber furnace, ashing furnaces, muffle furnace and dental furnaces too. Laboratory furnaces are generally used to heat small materials or test specimens over 1000°C. Below mentioned is the list of applications of laboratory muffle furnace :
• Research and development.
• Heat Treatment.
• Brazing and Soldering.
• Air and Space Industry.
• Petro chemistry.
• Material Testing and Quality Control Laboratories.
• Coal and Mining.
The working principle of a lab muffle furnace which is also known as a retort furnace is to heat the air inside its chamber using the basic fundamentals of thermal convection and thermal radiation. The name muffle furnace is derived from the fact that the internal ceramic chamber of the furnace which is also known as muffle is wrapped up in vast layers of insulation so as to prevent heat loss and achieve high temperatures. The high temperatures inside a muffle furnace attained by utilizing heating properties of Nichrome (nickel-chromium) wires which are called electrically operated heating elements. The temperature regulation in a furnace is highly dependent on the efficiency of electronic controller unit, although best results can only be obtained by applying PID controlled units, PID stands for proportional integral derivative controller. The laboratory muffle furnaces are not equipped with sophisticated cooling system as it is mostly not required. Most of the time a simple fan based exhaust system is installed and cooling is performed by this simple fan system supported by a chimney that too if desired in special cases. The main utility of this furnace exhaust system is to take out the toxic gases from the inner chamber which comes out during heating of the testing materiel / specimen inside the chamber. Hence the chamber gets sanitized of any toxic gases which may have evolved during the heating of materiel inside the lab muffle furnace. The muffle furnace is used when a controlled atmosphere is desired to prevent oxidation during heat treatment in high temperatures.