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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.


Technical Feature Value
Model 877
Temperature Range 100°C to 1300°C
Number of Calibration Points 8 as standard, 16 to special requirements
Diameter of sensors 4 x 6mm + 4 x 8mm
Depth of Immersion 180mm
Accuracy ±0.25°C to ±0.1°C at 1000°C (using comparison techniques)
Warm-up Times* 1 hour to 700°C 3 hours to 1300°C
Stabilisation Time* 1 hour to ±0.25°C
*these times may increase as the windings age or if the supply voltage is low.
Power 3kW, 208-240Vac, 50/60Hz 3kW 115Vac, 50/60Hz
Dimensions 425mm Diameter, weight 25kgs
Accessories 877/01 Equalising Block 4 x 8mm + 4 x 6mm i.d. (standard), 877-01S Equalising Block 16 x 6mm (special), 877/01E Equalising Block – other configurations (contact Isotech) – 877/02 Platinum Foil Temperature Barrier.
How to order 877 Thermocouple Calibration Facility including Standard Equalising Block. Please specify voltage needed.


Saturn Model 877

100°C to 1300°C

The Saturn spherical furnace comprises a number of concentric shells. The outer shell of spun metal is for containment and support.

  • Accuracy 0.25°C at 1000°C
  • Thermocouple Calibration Furnace to 1300°C
  • Central Zone of Zero Heat flux

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