This is the first new thermometer, after the introduction of ITS-90, to be specifically designed to give optimum performance up to the aluminum point. Its 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 temperature range and design of this new unit means that we offer 25.5 Ω (Ro). 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-metre 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 carrying 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 NIST Traceable or UKAS Accredited calibration.
A comprehensive handbook and tutorial will help you get the very best performance and stability from your 670.