Isotech 877 Saturn Thermocouple Calibration Furnace
- Accuracy 0.25°C at 1000°C
- Central Zone of Zero Heat flux
- Range 100°C to 1300°C
The Isotech 877 Thermocouple Calibration Furnace is a high‑performance calibration system designed for accurate and repeatable thermocouple calibration up to 1300 °C. At the core of the system is a unique spherical furnace architecture, built from multiple concentric ceramic and metal shells. This design creates a central zone of zero heat flux, ensuring that all measuring junctions experience an exceptionally uniform temperature environment.
With the ability to calibrate up to 15 thermocouples simultaneously, and with accuracies between ±0.25 °C and ±0.1 °C at 1000 °C, the 877 delivers performance previously achievable only with far more expensive heat‑pipe systems.
Spherical design for superior uniformity
The furnace consists of an outer spun‑metal shell for structural support, followed by a layer of ceramic fibre insulation. Inside this is a ceramic spherical mantle containing the heater windings, and at the centre lies a solid cast ceramic sphere with 8 or 16 thermocouple tubes. When fully inserted, the thermocouple junctions sit within a few millimetres of each other at the centre of the sphere, creating an exceptionally uniform temperature zone ideal for comparison calibration.
High capacity with high accuracy
The standard configuration includes 8 tubes (4 × 6 mm and 4 × 8 mm), but the furnace can be supplied with 16 tubes or with larger diameters up to 10 mm. Despite this capacity, the furnace maintains excellent uniformity thanks to its geometry and the use of modern ceramic materials that combine low mass with high stability.
Fast warm‑up and stable control
The furnace reaches 700 °C in about 1 hour and 1300 °C in approximately 3 hours. Once at temperature, it stabilizes within ±0.25 °C in roughly one hour. The external control system uses power feedback to compensate for supply voltage variations, while a digital filtering circuit minimizes drift and noise, ensuring stable and reliable operation during extended calibration runs.
No contamination of thermocouples
Unlike furnaces that use metal equalizing blocks, the 877 employs only ceramic materials in the measurement zone. This prevents contamination of thermocouples through diffusion or chemical interaction — a critical advantage for high‑temperature calibration.
Options and enhancements
The 877 can be configured with several optional features:
- > 16‑tube insert for increased capacity
- > Larger‑diameter inserts up to 10 mm
- > Platinum foil temperature barrier for near‑perfect uniformity (differences < 1 µV between two Type R thermocouples)
- > Blackbody option for infrared calibration
- > Custom equalising blocks
Each furnace is supplied with a spare set of windings and a comprehensive handbook to simplify maintenance.
The Isotech 877 Thermocouple Calibration Furnace combines capacity, accuracy and thermal uniformity in a way that few systems can match. Its spherical design, advanced ceramic construction and sophisticated control system make it an excellent choice for laboratories requiring reliable, high‑quality thermocouple calibration up to 1300 °C.
