LINEAR POLARIZATION SYSTEMS
Description
The Linear polarization resistance technique measures corrosion-rate continuously in real-time, from a probe permanently installed in the corrosive fluid. This electrochemical measurement is based on applying a small potential shift to a corroding metal electrode, the resultant current being proportional to the corrosion rate. Linear polarization instrumentation converts the current measured to corrosion rate readings in mils per year (mpy).
Applications
Although limited to electrolytically conducting fluids, the response time and data quality make linear polarization the corrosion monitoring method of choice, where applicable. This time proven technique has been used successfully in almost all water-based corrosive fluids of which the following are prime examples.
- Cooling water systems
- Secondary recovery systems
- Potable water treatment and distribution systems
- Amine sweetening
- Waste water treatment systems
- Pickling and mineral extraction processes
- Pulp and paper manufacturing
- Hydrocarbon production with free water
LPR PROBES
These probes are available in a wide variety of designs to accommodate most customer needs. The major design categories are:
LP1100
1-inch and 2-inch threaded NPT pipe plug bases.
LP4100
Retractable at pressures up to 1500 psi.
LP2000
1-1/2 inch NPT, on an extension shaft.
LP7100/LP7220
Pin-type and flush electrode probes for use with 2" high pressure access systems. For retrieval under pressures up to 3600 psi.
TF0222/TFO220
Laboratory cells.
Cortest also offers a full range of two-electrode polarization probes.
SENSING ELECTRODES
All Cortest Linear polarization resistance probes are used in conjunction with a set of three screw-on electrodes. This allows the probe almost indefinite life, provided the electrodes are replaced on a regular basis.
Sets of electrodes are available in almost any metal, or commercially available alloy.
INSTRUMENTS
MS1000
This inexpensive, hand-held unit will measure both corrosion rate and electrode potential, with results being displayed on a 3-1/2 digit L.C.D. screen. Designed primarily for the water treating industry, this instrument will measure corrosion rates in the range of 0-200 mpy, and potentials in the range of 0-2000 mV.
MS1500
This is a comprehensive, hand-held data logger that will measure corrosion rates from two- and three-electrode linear polarization probes, galvanic currents, and "pitting indices". It has the capability to store up to 3100 readings from as many as 100 different probes. Current measurements can be displayed and historical data reviewed on a 4-line (20-character) L.C.D. screen. An RS-232 port allows download of data to any IBM compatible PC for advanced data presentation and reporting.
MS3500L
Permanently installed at a single probe location, this instrument will continuously measure and store corrosion rates from two and three electrode polarization probes, and three electrode polarization probes, galvanic currents, and pitting indices. It has a maximum capacity of 3100 readings before data download is required to the customer's notebook PC, or Cortest's unit, via the onboard RS-232 port. A modified version incorporates a 4-20 mA loop facility for continuous transmission of data. AN on-board, L.C.D. screen allows visual review of current and historical data.
MS2500L
Dedicated to a single probe location, this permanently installed transmitter will continuously measure corrosion rates on three electrode polarization probes, and will continuously transmit this information via a 4-20 mA loop to the client's data logger or control computer. The transmitter can also be used in conjunction with Cortest's receiver, or eight-channel data logger.
MS3011
These comprise single-channel, automatic, and corrosion-rate meters for use with three electrode polarization probes. Designed to fit either a 19" control-room rack, or for field mounting in weather-proof/explosion-proof housings. Versions are available with on-board strip-chart recorders, or with a variety of signal outputs to match customer-supplied data loggers, recorders and/or computers.
MS6000
This modular system mounted in a 19" NEMA rack will accommodate up to 12 monitoring channels. The customer may select from corrosion rate (3-electrode polarization), galvanic, and hydrogen permeation measurement modules, and may "mix and match" these units in any combination up to 12. Data is collected on a continuous basis, and transmitted via a customer selectable output, to any type of data logger, multi-channel recorder, or computer. The client may also elect to use this unit in conjunction with the Cortest multi-channel data logger.
MS5000
Similar to the modular system, this unit has a maximum of eight measurement channels, configurable to measure corrosion rate (3-electrode polarization), galvanic current, and hydrogen permeation current. Unlike the modular series, this unit has an on-board microprocessor facility that allows data storage and manipulation. The 4-line (20 character) screen displays current measurement, and allows review of stored data. An RS-232 port is available for data transfer.
CONTACT:
Cortest Instruments, Ltd.
10 Riverside Business Park
Stoney Common, Stansted
Essex CM24 8BP
United Kingdom
PHONE: 44-1-279-816630 FAX: 44-1-279-816730
e-mail: cortestinst@mcmail.com
web site: www.cortest.com