Softening Of Hard Water
Water from whatever source it comes from contains (Ca++),
Magnesium (Mg++) & Sodium (Na-) present as sulfates,
chloride & bicarbonates of these ions.
By hard water, we mean water that it contains calcium &
magnesium salts in excess, which hinders formation of Soap,
Lather during washing of clothes and which may form deposits
in metal surfaces of equipments which carry this hard water.
Example:
Scale formation in boiler tube, Domestic piping & Geysers
heaters, Coolers. The hardness therefore has to be removed
or converted into a Soluble form. For removal of hardness
(Ca & Mg Ions) Water Softening through ion exchanger
resin is the ideal process to convert the hardness forming
ions into soluble Sodium (Na) ions. The TDS being sum of
Ca, Mg & Na is does not change but water becomes soft,
that means it is fit for Laundry, Cooling water make up
& Steam Production in Boilers.
What is a Hard Water Softening Resin:
Ions Exchange Resin are Copolymers of Polystyrene Di-Vinyl
Benzene & when these are charged (or brought into contact)
with common salt (NaCI), they absorb Sodium ions on their
surface as per following Equation: (Reactions during Charging)
RCa + 2NaCI = R (Na) 2 + 2 CaCI2
RMg + 2NACl = R (Na) 2 + MgCl2
Here 'R' denotes Resin.
After charging water is passed through the Resin-bed to
remove excess salt (Rinsing).
Reaction During Service Run:
R (Na)2 + Ca(HCO3)2 = RCa +2NAHCO3
R (Na)2 + Mg(HCO3)2 = RMg +2NAHCO3
R (Na)2 + CaCI2 = RCa+ 2NaCI
R (Na)2 + MgCI2 = RMg +2NACI
When all Sodium absorbed on resin surface is exhausted the
resin does not accept any Ca, Mg and has to be recharged
or regenerated with Com mom salt (as per above process).
Before recharging it is necessary to backwashing i.e. by
making the raw water enter the vessel from inlet side &
flowing through the entire bed of resin to loose it for
regeneration.
When to Regenerate:
In a softener which is rimming to produce Soft Water if
1. Hardness shoots up from its steady value
of less than 5 ppm.
2. If the theoretical outlet between two
regenerations is already achieved.
Maintenance Instructions:
In a portable Softener there are precautions only to be
taken and no major maintenance is involved.
However following components require replacement if these
start leaking of get corroded.
Inlet
flexible pipe & nipple.
Multipart
valve 3/4" size which has to be operated through a
Single lever to do all
operations i.e. backwashing rinsing & lining up through
same valve.
FRP Body
if its gets cracked.
Softener
Resin (Sodium Base) if it is badly fouled.
Important Instruction:
When changing the position of lever of multi-port
valve, always close the water supply first & after changing
the lever open the same
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