Processing Magazine

Electro-Pneumatic Positioners Ideal for Harsh Environments

March 10, 2010
New line of valve positioners stands up to chemical and food processing applications for complete valve automation in harsh environments. The series are part of a comprehensive line of pneumatic and electro-pneumatic positioners, including auto-calibrating "smart positioners" with automatic DA and RA detection, and an explosion-proof, FM/CSA-approved model. Built for high-performance valve automation applications, the series includes corrosion-proof stainless steel and explosion-proof models. The explosion-proof electro-pneumatic positioner is available in both FM- and CSA-approved versions, designed to withstand and contain explosions inside the enclosure, preventing release of flames to the surrounding areas. Enhanced process-protection models lock down the system via a fail-freeze function in the event the 4-20mA input signal is lost. For applications requiring greater cost economy, the line of electro-pneumatic positioners is available in rotary (EPR) or linear (EPL) configurations. The series positioners accept an analog 4-20 mA input signal, and have rugged aluminum diecast enclosures and stainless steel gauges standard. These vibration-resistant positioners provide precise calibration with simple span and zero adjustments, are repeatable within ±0.5 percent F.S., and are certified by NEMKO for ATEX and Eex md IIB T5. PP series pneumatic positioners utilize an input signal of 3-15 psi, capable of direct or reverse action with split range available. Like the electro-pneumatic line, the pneumatic positioners are available in rotary (PPR) or linear (PPL) versions, and have various orifices available to increase or decrease flow as required.