ER & LPR Monitoring SystemsER & LPR Monitoring Systems

Popular Corrosion Monitoring Popular Corrosion Monitoring TechniquesTechniques

• Weight Loss Coupons

• Linear Polarisation Resistance Probes (LPR)

• Electrical Resistance Probes (ER)

• CEION Probes

• Hydrogen Probes

• Biofilm probes

Weight Loss CouponsWeight Loss Coupons

Weight Loss CouponsWeight Loss Coupons

3 inch strip coupons before cleaning 3 inch strip coupons after cleaning

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3” Strip (pair) Multi –disc 6” Strip (pair)

Flush Disc

Ladder Strip (pairs)

ER: The Ratiometric ER: The Ratiometric PrinciplePrinciple

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 ProbesER ProbesCan be used in all systems(Gas, Water, Oil)

Can measure erosion

Low sensitivity

Thinner elements improve sensitivityAt 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)

•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 Linear Polarisation Resistance (LPR)(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

ProbesProbes

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 SYSTEMSACCESS SYSTEMSRETRACTABLERETRACTABLE

Flanged LPR assembly with protruding electrodes

LINEAR POLARISATION RESISTANCE (LPR)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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