DUAL EC Monitor
Electrical Conductivity (EC) of Water.
An EC monitor measures the potential for an electrical current to be transported through water. This is known as molar conductivity (electrolytic conductivity) and is measured in siemens (S). Electrons are able to flow through the water from one set of electrodes to another not because of the water molecules themselves, but because of the ions dissolved in the water. It is these ions that transport the electrons.
Pure water is not a good conductor of electricity. Ordinary distilled water in equilibrium with carbon dioxide of the air has a conductivity of about 10 x 10-6 W-1*m-1 (20 dS/m). Because the electrical current is transported by the ions in solution, the conductivity increases as the concentration of ions increases.
Thus conductivity increases as water dissolved ionic species. More:
Typical conductivity of waters:
Ultra pure water 5.5 · 10-6 S/m
Drinking water 0.005 – 0.05 S/m
Sea water 5 S/m
Electrical Conductivity and TDS
TDS or Total Dissolved Solids is a measure of the total ions in solution. EC is actually a measure of the ionic activity of a solution in term of its capacity to transmit current. In dilute solution, TDS and EC are reasonably comparable. The TDS of a water sample based on the measured EC value can be calculated using the following equation:
TDS (mg/l) = 0.5 x EC (dS/m or mmho/cm) or = 0.5 * 1000 x EC (mS/cm)
The above relationship can also be used to check the acceptability of water chemical analyses. It does not apply to wastewater.
As the solution becomes more concentrated (TDS > 1000 mg/l, EC > 2000 ms/cm), the proximity of the solution ions to each other depresses their activity and consequently their ability to transmit current, although the physical amount of dissolved solids is not affected. At high TDS values, the ratio TDS/EC increases and the relationship tends toward TDS = 0.9 x EC.
In these cases the above-mentioned relationship should not be used and each sample should be characterized separately.
Electrical conductivity can be expressed using a number of different units, but the typical unit is siemens per meter2 per mole (S/m2/mole) or millisiemens per centimetre (mS/cm) or microsiemens(µS)
One milli siemens/cm = 1,000 micro siemens/cm or ECs. To convert mS/cm to µS/cm, multiply the reading on the instrument by 1000.
FEATURES DUAL EC MONITOR
- Highly efficient and accurate due to its advanced microprocessor technology.
- Displays EC levels of the Feed Water and Product Water with in & out electrode probes.
- Auto-Off function conserves battery power. The unit shuts off automatically after 3 minutes.
- Dual Range – Measures from 0-999 µS, with a resolution of 1 ppm. From 1000 to 9990 µS, the resolution is in 10 µS increments, indicated by a blinking ‘x10’ image.
- Factory Calibrated: calibrated to 1413 µS. The DM-2EC features digital calibration.
- Diagnostic error messaging
- Shielded sensor cables
- Comes equipped with 1/4 inch Mur-lok® Quick-Connect T-fittings. Also available with 3/8″ or 1/2″ fittings.
- Installs quickly and easily.
Differences from the DM-1:
- Measures EC (Electrical Conductivity) in µS (micro-Siemens).
- Designed for commercial/industrial applications.
- Stronger, water-resistant casing.
- Digital calibration can be done individually on each line.
- Improved design, including an extra large, easy-to-read LCD display.
- Longer, waterproof, shielded cables.
- Variable mounting bracket.