Linear polarisation
A small potential shift relative to the corrosion potential is applied to the test electrodes and the resulting current is measured: their ratio gives the instantaneous corrosion rate, expressed in MPY (mils per year).
Measuring probes
E‑CORR corrosion
Probes for the continuous monitoring of corrosion. In addition to the general corrosion rate, they measure electrochemical noise, from which they derive an index of localised corrosion (pitting), and compensate for the conductivity of the water. Two versions: E-CORR COLD for cold water and E-CORR HOT for hot water.
- General and localised corrosion
- Linear polarisation resistance
- Two 4/20 mA outputs and RS485
- COLD up to 50 °C, HOT up to 240 °C
0.001MPYResolution
0 – 100Localised corrosion index
240°CMaximum temperature (HOT)
34.5barMaximum pressure (HOT)
Operation
Operating principle
Localised corrosion
The probe also measures electrochemical noise and derives from it an index from 0 to 100 of localised corrosion, or pitting: the value 100 corresponds to AISI 304 stainless steel in 10% ferric chloride.
Electronics in the probe
The signal is conditioned, amplified and digitised inside the probe, without separate transmitters: this avoids the interference and attenuation caused by long cables. The probe also measures the conductivity of the water and compensates for its effect on the measurement.
Versions
The two versions
E-CORR COLD
For cold water: evaporative cooling towers, cooling towers and closed cooling circuits. AISI 304 stainless steel body with protection against electromagnetic interference; three O-rings on the body allow the insertion depth to be adjusted.
- Sample temperature up to 50 °C
- Operating pressure up to 7 bar
- General corrosion 0.001 – 10 MPY
- Conductivity compensation 10 – 10,000 µS/cm
- IP65 protection
E-CORR HOT
For hot water and the most demanding conditions: heating and district heating circuits, geothermal plants, process water at high temperature and pressure. Titanium and PEEK body, with integrated cooling fins for high-temperature applications.
- Operating temperature up to 240 °C
- Operating pressure up to 34.5 bar
- General corrosion up to 995 MPY
- Conductivity compensation 10 – 50,000 µS/cm
- IP68 protection
Applications
Use and maintenance
Effects of the treatment
Corrosion depends on the chemistry and physics of the water (composition, temperature, velocity, conductivity) and on the pipe material: continuous measurement makes it possible to assess the effects of the chemical treatment in real time and to correct it.
Probe and coupons
The probe measurement is instantaneous, whereas removable coupons give the average weight loss over a long period: the two values are correlated but not necessarily equal. The probe is used to follow the trend and adjust the treatment; coupons may be used alongside it for comparison.
Maintenance
The electrodes must be replaced when heavily corroded; deposits not caused by corrosion, such as calcium carbonate, must be removed from the body and the base of the electrodes. The probe must not be left for long periods in stagnant water. Two test plugs, of 2.0 and 0.1 MPY, verify correct operation.
Technical data
Data sheet
| E-CORR COLD | E-CORR HOT | |
|---|---|---|
| General corrosion | 0.001 – 10 MPY | 0.001 – 995 MPY |
| Localised corrosion | index 0 – 100 | index 0 – 100 |
| Resolution | 0.001 MPY | 0.001 MPY or 1% of reading |
| Conductivity compensation | 10 – 10,000 µS/cm | 10 – 50,000 µS/cm |
| Reading interval | 1, 2, 5 or 20 min | 3 – 1,440 min |
| Alloy factor | 0 – 3 | 0 – 3 |
| Operating temperature | −10 / +50 °C | −10 / +240 °C |
| Operating pressure | 7 bar | 34.5 bar |
| Power supply | 24 VDC, 2 W | 24 VDC, 2 W |
| Outputs | 2 × 4/20 mA (general and localised), RS485 | 2 × 4/20 mA (general and localised), RS485 Modbus |
| Installation | In-line, NPT threaded connection | In-line, 3/4" NPT or BSP connection |
| Body | AISI 304 | Titanium and PEEK |
| Dimensions | 281.5 mm, Ø 23 / 43 mm | 280 mm, Ø 52 mm |
| Weight | 687 g | 1,150 g |
| Cable | 1.5 m, extensions available | 1.5 m, extensions available |
| Protection | IP65 | IP68 |
Electrode metals (alloy factor set according to the metal)
- Carbon steel
- Copper
- Admiralty brass
- AISI 304 stainless steel
- Aluminium 1100 and 6061
Other alloys (E-CORR HOT)
- Copper-nickel
- Bronzes
- AISI 316 stainless steel
- Duplex stainless steels
- Lead
Technical advice
Tell us about your application: our technical staff will recommend the most suitable model, configuration and accessories.