ER & LPR Monitoring Systems
Popular Corrosion Monitoring Techniques Weight Loss Coupons Linear Polarisation Resistance Probes (LPR) Electrical Resistance Probes (ER) CEION Probes Hydrogen Probes Biofilm probes
Weight Loss Coupons
Weight Loss Coupons 3 inch strip coupons before cleaning 3 inch strip coupons after cleaning
Top of line Middle of Line Bottom of Line 3” Strip (pair) Multi –disc 6” Strip (pair) Flush Disc Ladder Strip (pairs)
ER: The Ratiometric Principle SAMPLE REFERENCE The ratio of sample & reference elements resistance is a measure of the corrosion affecting the exposed sample element by a reduction in its surface area and therefore increase in its resistance. The ratio Rs/Rr is converted to metal loss in the measuring instrument. The slope of the metal loss curve is the corrosion rate
ER Probes Can be used in all systems (Gas, Water, Oil) Can measure erosion Low sensitivity Thinner elements improve sensitivity At the cost of probe life. Typical Flush Probe (High Pressure System) showing F20 (0.5mm thick element) Lifetime ½ element thickness
ELECTRICAL RESISTANCE (ER)
ELECTRICAL RESISTANCE (ER) Wire Loop Probe 1.0mm (40 thou’) element Lifetime ¼ of probe thickness
ER Wire loop probe with velocity shield in 2” HP access fitting
Tubular ER Probe (left) in retractable assembly. Max pressure 1000 psi
DCU3 Data Logger ER or LPR Configurations 4000 readings storage ATEX/CSA approval Also transmitter capability Probe mounted for HP applications, panel mounted for LP (retractable) assemblies
Linear Polarisation Resistance (LPR) Theory of Operation The theoretical basis of the LPR technique was founded in a publication dating back to 1957. In the LPR technique, a potential (typically of the order of 10-20 mV) is applied to a freely corroding sensor element and the resulting ("linear") current response is measured. The current measured in a conductive solution ie., a continuous phase of water is proportional to the ‘corrosion’ current and is converted to corrosion rate by multiplying the measured value by a conversion factor depending on electrode size and electrode material
Probes Linear Polarisation Resistance (LPR) Instant corrosion rates Used in conductive systems Can’t be used where oil is present Can’t be used in gas systems Typical flush mounted 3-electrode probe
ACCESS SYSTEMS RETRACTABLE Flanged LPR assembly with protruding electrodes
LINEAR POLARISATION RESISTANCE (LPR)
Multi-Function instrument HHU-M for upload from data loggers (ER & LPR configurations) and reading ER & LPR probes directly
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