Gefran have released the NaK series for temperatures above 500°C with sodium potassium fill material, and the Impact series which is a no fill, no rod design with the pressure sensor mounted in the sensor tip. The NaK and Impact series are available from ECEFast . For non mercury filled applications in addition to these solutions are the oil filled W series sensors for food packaging and pharmaceutical applications.
The majority of sensors used in extruders are the M Series, with rigid, or flexi stem design, and either standardised mV outputs or mA or voltage amplified outputs.
Gefran have innovated the ‘magnetic wand’ for non contact zeroing of output at process temperature. Ranges are available from 35 bars to 2000 bars and accuracies are standard at 0.5% and special at 0.25%. Calibration outputs of 80% are internally generated, and these match the automated calibration routines of the matching controllers.
Gefran have indicator units with alarms, and optional retransmitted process signals, or integrated fast controllers for closed loop control of the extruder drive based on the measured extrusion pressure. This assures protection of the barrel from overpressure, and optimum product quality.