5686-B Glass Capsule SPRT
Key features
- Miniature glass capsule SPRT designed for metrology work that requires small SPRTs.
- Temperatures range: –260 °C (13 K) to 232 °C and offers stability typically of 0.001 °C over a 100 °C range.
- Ideal for applications such as cryogenics, calorimetry, and other metrology work where traditional SPRTs may be too long or awkward.
- True SPRT, with high-purity platinum wire hand-wound on a glass cross frame in a strain-free design.
Product overview: 5686-B Glass Capsule SPRT
Precision, Stability, and Reliability for Extreme Temperature Measurement
Primary Standard SPRT for Cryogenic and Immersion Applications
The Fluke 5686-B Glass Capsule Standard Platinum Resistance Thermometer (SPRT) is designed as a primary standard instrument for converting temperature to resistance with uncompromising accuracy. Fully compliant with ITS-90, the 5686-B is part of the trusted Fluke Calibration SPRT family, delivering outstanding performance in both laboratory and demanding field environments.
Key Features and Specifications
- ITS-90 Compliance – The 5686-B meets the requirements of the International Temperature Scale of 1990 (ITS-90), with resistance ratios:
- W(302.9146 K) ≥ 1.11807
- W(234.3156 K) ≤ 0.844235
- Exceptional Temperature Range – Covers –260 °C (13 K) to 232 °C (505 K), making it ideal for cryogenic applications and high-precision temperature measurement across a wide spectrum.
- Compact Design – With a diameter of just 5.8 mm and a length of 56 mm, the 5686-B is well-suited for applications requiring a totally immersed probe or where space is limited.
- Fixed-Point Calibration Ready – Fixed-point calibrations are available from –200 °C to 232 °C, ensuring accuracy for critical measurement points.
- Superior Construction – The sensing element is made from high-purity platinum wire wound strain-free on a fused silica cross frame, and the special glass capsule is pressure-sealed with 5N pure helium to maintain integrity and performance.
Designed for Demanding Measurement Environments
- Low Temperature Excellence – Engineered for operation down to 13 K (–260 °C), the 5686-B is the standard of choice for cryogenic temperature measurement.
- Minimized Heat Flow – The glass capsule design supports full immersion, reducing heat flow from or to the sensor and improving measurement stability.
- Alternative to Long-Stem SPRTs – When traditional long-stem SPRTs are not suitable, the compact 5686-B Glass Capsule SPRT fits into vessels and setups where complete encasement is needed.
- Proven Reproducibility, Reliability, and Stability – Each thermometer is carefully annealed and tested for stability, delivering consistent, accurate results in both standard and challenging scenarios.
Why Choose the Fluke 5686-B Glass Capsule SPRT?
- Wide temperature coverage for both cryogenic and calibration applications
- Compact, fully immersible probe design for versatile use
- High-purity platinum element and strain-free construction for unmatched stability
- Pressure-sealed capsule maintains sensor protection and performance
- Meets rigorous international standards (ITS-90) for trustworthy measurement
For laboratories and industries where precise, stable, and reproducible temperature measurement is essential, the Fluke 5686-B Glass Capsule SPRT sets the benchmark for performance and reliability.
Specifications: 5686-B Glass Capsule SPRT
| Specifications | |
| Temperature Range | 5686: –260 °C to 232 °C (13 K to 505 K) |
| Nominal RTPW | 25.5 Ω |
| Resistance Ratio | W(302.9146 K) ≥ 1.11807 W(234.3156 K) ≤ 0.844235 |
| Drift Rate | 5686: < 0.005 °C per year over the entire range |
| Self-heating at TPW | < 0.002 °C under 1 mA current |
| Reproducibility | ±0.001 °C or better |
| R TPW Drift After Thermal Cycling | < 0.001 °C |
| Filling Gas | 5686: helium |
| Lead Wires | Four platinum wires, 30 mm long (1.18 in) |
| Size | 5686: 5.8 mm dia. x 56 mm long (0.23 x 2.2 in) |