Isotech 909 Family Working SPRTs Thermometers
- Three Stem Lengths
- Wide Operating Range
- Proven Design
- Nominal Sensitivity 0.1 Ω/°C 0.4 Ω/°C
The Isotech 909 Family offers a range of Work Standard Platinum Resistance Thermometers (SPRTs) designed for primary and secondary laboratories. These thermometers combine high accuracy, reliability and a wide temperature range from -196°C to 670°C, making them ideal for precision calibrations in a laboratory environment.
Excellent Stability and Durable Design
The Model 909 SPRTs feature a pure platinum resistance element, carefully wound and mounted in a stress-free construction. This prevents internal stress and ensures long-term stability. The element is encapsulated in a pure aluminum housing, which is preconditioned to minimize contamination and mechanical stress.
All splices are carefully welded to prevent resistance fluctuations. The thermometers feature silver-plated, multicore wires with low-loss insulation cable, ensuring reliable signal transmission.
Various Models and Materials
The 909 series includes several models, each optimized for specific applications:
| Model | Resistance | Temperature range | Outer Jacket | Features |
| 909Q | 25.5Ω / 100Ω | -196°C tot 670°C / -196°C to 550°C | Quartz | Visible internal components, recommended by Isotech |
| 909H | 25.5Ω / 100Ω | -80°C to 670°C / -80°C to 550°C | Metal | Metal Durable, internal alumina protection |
| 909L | 25.5Ω / 100Ω | -196°C to 165°C | Metal | Metal Optimized for low temperatures |
All models are available in three lengths: 480 mm, 550 mm and 600 mm, with a sensor length of 65 mm.
Optimal Calibration and ITS-90 Standards
The Model 909 SPRTs come standard with a certificate listing the RTPW and Wga value. Optionally, they can also be supplied with a UKAS calibration based on ITS-90 fixed points:
| Fixed point | Temperature (°C) | Typical Uncertainty (k=2) |
| Boiling point Nitrogen | -195,798 | ±5mK |
| Triple point Kwik | -38,8344 | ±1mK |
| Triple point Water | 0,01 | ±0,5mK |
| Melting point Gallium | 29,7646 | ±1mK |
| Fixed point Indium | 156,5985 | ±2mK |
| Fixed point Tin | 231,928 | ±2,5mK |
| Fixed point Zinc | 419,527 | ±3mK |
| Fixed point Aluminum | 660,323 | ±6mK |
Key Benefits
> High-quality platinum wire for exceptional stability
> Durable and contamination-free design for pre-aging and welding techniques
> Available in quartz and metal versions for various applications
> ITS-90 traceable calibration possible with UKAS certification
> Low self-heating: only 1mK per 25 microwatts
> Optimized for both primary and secondary laboratories
Applications
The Isotech 909 Family is used worldwide for:
> Calibration of industrial platinum resistance thermometers (PRTs)
> Research and development of temperature standards
> Interlaboratory comparisons and accreditation audits
> Use in metrology laboratories and production control
