Posted to News on 25th Apr 2007, 16:42
Cost-effective conductivity sensors improve accuracy
Invensys Process Systems is introducing a compact, non-invasive conductivity sensor for high-purity measurement in low-volume liquid applications. The Foxboro FT10 Electrodeless Conductivity sensor features patent-pending technology for highly accurate conductivity sensing, plus a flow-through design for reduced operational and maintenance costs.
To facilitate its use in high-purity applications, the FT10 is equipped with virgin PFA Teflon-wetted materials and leak-free welded connections that eliminate internal threads, O-rings and gasket seals. For low-volume, small line size liquid applications, the FT10 is available with Teflon tube sizes of 1/2inch, 3/4inch or 1inch, and can measure process fluids with temperatures up to 140degC (284degF) and at pressures up to 100psig.
The compact FT10 sensor housing measures 7 x 5 x 2inches and is constructed from ultra-high molecular weight polyethylene. The FT10 can be installed as an integral part of the process piping or surface mounted, and is suitable for demanding applications in the semiconductor, speciality chemical, electronic and LED industries, as well as selected pharmaceutical applications. These include the measurement of high-purity and/or high concentrations of aggressive chemicals such as: hydrofluoric, hydrochloric, nitric, and sulfuric acids; ammonium hydroxide; and tetra-methyl ammonium hydroxide.
Joseph Downey, marketing director at the Foxboro Measurements & Instruments Division of Invensys, comments: "Accurate measurement of high-purity fluids has traditionally involved expensive devices available from only a few sources. The FT10 now offers a cost-effective alternative. The FT10 combines a proven flow-through design with advanced conductivity sensing technology for accurate high-purity sensing across the full range of conductivities, while minimising operational and maintenance costs."
No need for probes
The Foxboro FT10 flow-through design allows the process fluid to pass through an opening in the sensor, thus eliminating the need to insert probes into the process line. As the fluid passes through the sensor, conductivity is measured with Foxboro's patent-pending, multi-toroid technology. The primary toroid induces electric current in the process fluid; the voltage created is detected by secondary toroids and is converted to a conductivity measurement. This multi-toroid design allows the FT10 to measure accurately the full scale of conductivity, ranging from 0-2000mS/cm.
Thanks to its flow-through design, the FT10 reduces maintenance requirements and costs, since neither the sensing element nor the housing contacts fluid. Furthermore, the Foxboro FT10 can be calibrated in line to improve production efficiencies and further reduce maintenance costs. Invensys also offers the Foxboro EP485 series precision resistance calibration plug, which permits a high-accuracy calibration of the FT10 without a decade resistance box.
