Tube Furnaces: Tube furnaces are one of the most popular types of thermocouple calibration furnaces. They typically have a cylindrical heating chamber, often made of ceramic or refractory materials. The long, narrow design of the tube allows for a uniform temperature distribution along the length, which is ideal for calibrating thermocouples of various lengths. Tube furnaces can operate at a wide range of temperatures, from relatively low temperatures for general applications to extremely high temperatures for specialized industries like metallurgy.

Box Furnaces: Box furnaces, as the name suggests, have a box - shaped heating chamber. They offer a larger working volume compared to tube furnaces, making them suitable for calibrating multiple thermocouples simultaneously or larger - sized samples. Box furnaces are also known for their versatility in terms of temperature control and can be customized to meet specific calibration requirements.

Split - Tube Furnaces: Split - tube furnaces are designed with a split - open heating chamber. This unique design allows for easy access to the furnace interior, which is convenient for inserting and removing thermocouples. Split - tube furnaces are often used in applications where quick and frequent calibration is required, as they reduce the time spent on sample loading and unloading.