Water softening

From Wikipedia, the free encyclopedia

A water softener reduces the calcium or magnesium ion concentration in hard water.

These "hardness ions" cause two major kinds of problems:

• The metal ions react with soaps and calcium sensitive detergents, hindering their ability to lather properly and forming an unsightly precipitate - the familiar scum or "bathtub ring". Presence of "hardness ions" also inhibits the cleaning effect of detergent formulations.
• More seriously, calcium and magnesium carbonates tend to precipitate out as adherent solids on the surfaces of pipes and especially on the hot heat exchanger surfaces of boilers. The resulting scale buildup can restrict water flow in pipes. In boilers, the deposits act as thermal insulation that impedes the flow of heat into the water; this not only reduces heating efficiency, but allows the metal to overheat which, in a pressurized system, can lead to catastrophic failure.

How Rechargeable Water Softeners Work.

The water to be treated passes through a bed of the resin (HCR/S/E/S DOW CHEMICAL type resin); the negatively-charged resins absorb and bind metal ions, which are always positively charged. The resins initially contain univalent sodium ions, which exchange with divalent calcium and magnesium ions in the water. This exchange eliminates the possibility of precipitation and soap scum formation. As the water passes through both kinds of resin, the hardness ions replace the sodium which are released into the water.