Model 670 Standard Platinum Resistance Thermometer. SPRT. Temperature Range: -200°C to 670°C
Model 670 Standard Platinum Resistance Thermometer construction permits the four internal platinum lead wires to expand and contract in the same manner as those of silver-point thermometers.
The all-quartz construction of the support-members gives the most stable performance with minimal drift, and a unique platinum radiation shield prevents heat radiating up the inside of the sheath.

The construction, including the coiled sensing
element, heat-shunt baffles and light scattering
barriers, creates a thermometer of unsurpassed
stability.
Because the 670 goes beyond the temperature
range of oxide growth to the level at which the oxide dissociates, the 670 is filled conventionally with argon containing 10% oxygen.
A 2-meter length of low thermal emf, high
temperature, screened cable is connected
in the handle, via a strain-relieving transition,
to the all pure-platinum construction of the
thermometer.

Gold-plated U-shaped terminals complete the cable construction, and the 670 is delivered in an elegant soft lined carry-case of our own design.
A 670 is delivered only after a stabilizing process which is complete when the reproducibility of RTPW is within 0.0005°C after excursions to the extremes of its temperature range. Values of RTPW and WGA are routinely provided with the 670.
The 670 can be supplied with RTPW and WGA only or with full UKAS calibration. “With calibration” means that you will get an Internationally accepted Fixed Point calibration.
For best accuracy, recommended maximum measuring currents for the 670 is 1mA although up to 10 times this current should not permanently damage the standard.
A comprehensive handbook and tutorial will help you get the very best performance and stability from your 670. The thermometer has a standard length of 650mm.