Isotech Primary SPRT 670 Family Thermometers
- Useable Range -200°C to 670 °C
- 25.5 Ohm SPRT
- Outstanding Performance
- Long term drift from 0.001°C / year dependingon use
- Sensitivity 0.1Ω / °C (25.5Ω) ,0.4Ω / °C (100Ω)
The Isotech 670 series consists of ultra-stable standard platinum resistance thermometers (SPRTs) designed for primary and secondary laboratories. With a temperature range of -200°C to 670°C and unmatched performance in terms of stability, reproducibility and low drift, these thermometers are ideal for high-performance temperature calibrations according to the ITS-90.
The 670SQ, 670SH and 670SL are specially designed to provide optimum performance in various laboratory environments. The 670SQ, built with all-quartz glass construction, offers the best performance for achieving minimum drift and maximum reproducibility, while the metal versions (670SH and 670SL) offer high mechanical strength and durability.
Outstanding Stability and Construction
The 670SQ is designed with an innovative internal structure that minimizes thermal expansion and contraction. The four internal platinum conductors can move independently, eliminating mechanical stresses. In addition, a platinum heat shield prevents radiation losses, leading to exceptional stability.
The construction of the 670SH and 670SL includes a metal jacket, providing additional robustness for environments where mechanical impact or vibration may occur. The low-temperature 670SL variant is specially optimized for applications down to -200°C, while the 670SH is suitable for use up to the aluminum fixed point of 660.323°C.
Technical Specifications
| Model | Range(°C) | Ro (Ω) | Sheat Material | Diameter | Length | Measurement Area |
| 670SQ | -200 to 670 | 25.5 | Quartz | 7,5 mm | 650 mm | 35 mm |
| 670SH | -80 to 670 | 25.5 | Metal | 6 mm | 650 mm | 35 mm |
| 670SL | -200 to 165 | 25.5 | Metal | 6 mm | 480 mm | 35 mm |
The 670SQ is recommended for primary laboratories because of its low self-heating. The metal housing makes the 670SH suitable for more robust high-temperature applications, while the 670SL offers a cost-effective solution for low-temperature applications.
UKAS Calibration and Accuracy
For optimum accuracy, the 670 series can be supplied with UKAS calibration, including validation at ITS-90 fixed points.
| Fixed Point | Temperature (°C) | UKAS Uncertainly (k=2) |
| Argon Triple Point | -189,3442 | 0,5 mK |
| Mercury Triple Point | -38,8344 | 0,3 mK |
| Water Triple Point | 0,01 | 0,1 mK |
| Gallium Melting point | 29,7646 | 0,2 mK |
| Indium fixed point | 156,5985 | 1 mK |
| Tin fixed point | 231,928 | 1 mK |
| Zinc fixed point | 419,527 | 1,2 mK |
| Aluminium fixed point | 660,323 | 2 mK |
The 670SQ is delivered after an extensive stabilization process, which verifies the reproducibility of RTPW within 0.0005°C after exposure to the extreme temperatures within the operating range.
Applications
The Isotech 670 series is ideal for:
Primary and secondary laboratories working with ITS-90 standards.
Temperature calibration of SPRTs and industrial PRTs.
Interlaboratory comparisons and accreditation audits.
Research and development of advanced temperature standards.
Each thermometer comes in a soft-lined carrying case, along with a comprehensive manual for optimal performance and longevity.
