Inductive Proximity Replacement for Optical Sensors in Washdown Environments
Replacing optical sensors with 316L stainless inductive proximity units eliminates washdown fluid blinding and restores line uptime in CIP zones.
PEEK Sensing Face
Polymeric Interface
Polyetheretherketone serves as the primary contact membrane for flush-mounted pressure and level transmitters exposed to aggressive media. Thermoplastic construction provides high resistance to chemical attack while maintaining mechanical stability across elevated operating temperatures. Polyetheretherketone sensing face components isolate internal strain gauges from corrosive process fluids without requiring secondary diaphragm seals.
Fluid pressure deflects the flat polymer boundary, transferring mechanical stress through an internal fill fluid to the silicon measuring cell. Wall thickness and diameter ratios determine the deflection sensitivity of the barrier against hydraulic shock. Mechanical creep under sustained load limits the maximum continuous operating temperature of the polymer membrane below the glass transition point of the base resin.
Calibration Drift
Thermal expansion mismatches between the plastic diaphragm and the metallic sensor housing introduce zero-point shifts during rapid temperature cycles. Standard calibration procedures require zero and span adjustments at reference laboratory conditions before field installation to compensate for initial mechanical seating. Creep relaxation of the polymer matrix under continuous pressure reduces the output signal over long operational periods.
Recalibration intervals must account for environmental aging and chemical absorption within the membrane material. Measurement error increases when process temperatures deviate significantly from the baseline calibration value.
Installation Tolerance
Torque specifications defined by the manufacturer govern the mounting of the sensor into threaded process connections to prevent distortion of the sealing face. Overtightening the retaining nut compresses the polymer disc unevenly, inducing false offset errors in the output signal. Flush alignment with the interior pipe wall prevents flow turbulence and solids accumulation across the active measuring surface.
Mating flange dimensions must match the outer diameter of the polymer disc to ensure adequate mechanical support against high-pressure impulses.
Media Compatibility
Chemical resistance charts govern the application limits of the polyetheretherketone diaphragm against specific acids, organic solvents and halogenated compounds. Permeation rates of gases through the thermoplastic barrier restrict usage in high-vacuum or extremely dry gas services where vapor migration damages internal electronics. Particulate slurries cause abrasive wear on the exposed polymer surface, altering wall thickness and reducing burst pressure ratings over time.