The Saturn spherical furnace comprises a number of concentric shells. The outer shell of spun metal is for containment and support. Inside this is a layer of ceramic fibre. Within the fibre is a ceramic spherical mantle containing the heater windings. In the centre of the furnace is a solid cast ceramic sphere with 8 or 16 tubes, to be used for the thermocouples requiring calibration. Isotech’s calibration furnace is revolutionary from a number of aspects: It is spherical, and its design ensures a central zone of constant temperature. Thermocouples are inserted around the circumference of the furnace. When fully inserted the measuring junctions are within a few millimeters of each other at the centre of the sphere. Up to 15 thermocouples can be calibrated simultaneously. The accuracy is between ±0.25°C and ±0.1°C at 1000°C. Larger tube diameters will give larger gradients, as will larger numbers of tubes. The precision of this furnace has previously been achieved only by using heat pipes. Because of the design the price is only one half to one third that of a bath with comparable accuracy and much smaller capacity of calibration. The use of newly developed modern ceramic materials has enabled high accuracy, low mass and high stability to be obtained. The Saturn system will not contaminate your thermocouples unlike some furnaces that have metal equalising blocks.