Scientific Technologies' Hazardous Level Sensor
RPM level measurement sensors can be used in all hazardous locations. Sensors are available in lengths up to 20 ft, in various mounting configurations, and with resistive chain or loop powered 4-20 mA outputs. The sensors have only one moving part, an anti-stick float that moves up and down a vertical stem. A permanent magnet inside the float acts on a series of closely spaced reed switches and resistors inside the stem.
Scientific Technologies: 888/349-7098; www.stiapg.com