This economically-priced Standard Platinum Resistance Thermometer, Model 909, is the workhorse of calibration laboratories all over the world. In 2007, we reviewed our range of SPRTs and now have new models in the 909 family: the 909L and 909H. The wide temperature ranges and economical pricing make this thermometer ideal for the secondary laboratory. For smaller uncertainties to suit the Primary Laboratory, refer to the Model 670 SPRTs.
The resistance element is of pure platinum, coiled and mounted in a strain-free construction. The former is of pure alumina material, and all parts have been pre-aged to eliminate contamination and strain. All joints are welded to minimize resistance changes. The leads are brought to a handle assembly where they are connected to a low loss cable, which is 2m long and screened.
The 909Q has a quartz sheath, while the 909L and 909H have metal sheaths. Although metal-sheathed thermometers appear more robust than the quartz glass models, it should be noted that ALL SPRTs are fragile devices, and must be handled with care.
Three thermometer lengths are available: standard length, 480mm, extra length, 550mm or maximum length, 600mm.
Quartz glass thermometers have the advantage that the internal components are visible and can be inspected, and continue to be our recommended models. The low temperature models have excellent immersion characteristics and a significant cost saving when compared to the higher temperature models.
The Model 909 is supplied with a calibration certificate, giving RTPW and Wga. Alternatively, we can provide a complete UKAS calibration certificate (see specifications). For transportation and storage, the Model 909 is supplied in its own attractive carrying case.