Scale is a coating or precipitate deposited on surfaces that
are in contact with hard water. Water that contains carbonates or bicarbonates
of calcium or magnesium especially is likely to cause scale. When water is
heated or evaporation takes place or if there is a change in water pressure,
scale minerals precipitate layers of rock-like deposits inside pipes, water
heaters, equipment, fixtures and glassware. While most common scale is a result of calcium carbonate, other combinations of ions commonly found in water offer a variety of scale. These substances include calcium bicarbonate, calcium sulfate, calcium chloride, magnesium carbonate, magnesium bicarbonate, magnesium sulfate and magnesium chloride.
Scale is most visually evident as white to off-white
deposits that buildup inside faucets, water pipes, equipment, fixtures and
heating elements. Scale formation usually is hard and very difficult to clean.
Scale formation can occur on virtually any surface in contact with water,
provided the water has some content of scale-forming chemistry. With more than
85 percent of U.S. water considered hard, the problem is widespread. Many
billions of dollars are lost in business and industry each year due to scale
buildup. Scale formation will cause corrosion in pipes and equipment, downtime
and high maintenance expenses. Just a quarter inch of scale buildup will increase
heating costs by as much as 40 percent.
How is Scale Formed?
Principally, scale forms from calcium carbonate. Its
structure consists of tiny crystals. The most common form of crystalline
calcium carbonate is called calcite. Calcite begins formation when a dynamic
called supersaturation occurs. Supersaturation can be illustrated by
visualizing sugar in a glass of water. If someone filled a glass full of water
and began to spoon sugar into the glass, the sugar would dissolve. However,
sugar will dissolve only up to a point where the water reached a maximum
saturation— at this stage, sugar then will remain in its solid form.
The point where a solid will no longer dissolve is called
the point of supersaturation. When calcium carbonate reaches the point of
supersaturation it begins to change from its dissolved form to a solid form.
This can occur even in total submersion.
The rate of formation of calcite is influenced by many
factors such as temperature and evaporation. These two factors certainly
account for accelerated scale formation in hot water pipes, water heaters and
on surfaces such as sinks, countertops and dishes.
Several technologies have been used successfully over the past
several decades to combat the effects from hard water and scale formation.
softening by ion exchange removes water hardness cations (positively charged)
of calcium and magnesium ions and replaces them, usually with sodium chloride
osmosis will remove approximately 95
percent of dissolved solids in the water. Water pressure against a reverse
osmosis membrane forces the water molecules through the semipermeable membrane,
but the larger contaminant molecules and bacteria are kept behind and flushed
to the sewer.
• Polyphosphates are used as a sequestering agent to control iron
and hardness and as coating agents to control corrosion by formation of a thin
passivating film on metal surfaces. In essence, they bind calcium and magnesium
in solution where they are less likely to precipitate and form calcite.
jetting and sand and plastic-bead blasting
can be used to remove excess scale buildup.
Though effective, these technologies have been scrutinized
by environmentalists over the past decade or so. A new technology has emerged
that can solve scale problems without the need of salts, chemicals or
Electronic Water Conditioning
Electronic water conditioning is a relatively new technology
that evolved from the use of magnetic fields in water treatment. Historically,
the performances of permanent magnets have been ultimately reliant on
controlled conditions such as flow rate. However, their energy levels and
fields are fixed. The advent of electronic systems introduced both variable
energy and frequency.
Electronic treatment is based on the principal of creating
an oscillating field of energy with the use of low frequency radio waves. As
water passes through a pipe delivering variable frequencies and energy levels,
a physical change in the preferred crystal structure of calcium and magnesium
occurs, tending to form the crystalline structure of aragonite rather than the
random crystalline structure of calcite. Aragonite is a form of calcite
crystallizing in the orthorhombic system and prefers remaining in solution and
not adhering to surfaces. Through this physical mechanism, electronic
conditioning alters the effects of calcium and magnesium carbonates with regard
to scale formation and reaction with soap to form curd. Precipitated aragonite
has a fine powder-like consistency that is not hard and does not intrinsically
adhere to surfaces.
There are several electronic descalers available on the
market today. Many use radio wave while others use square wave technology.
Another electronic descaler is one that creates a rapidly
alternating current in a frequency range that exceeds the best estimate of the
internal natural frequency of water. The natural frequency of water varies with
temperature, pressure, minerals present, pH and other factors. The current
generates an oscillating magnetic field within the pipe. The rapid oscillation
of the magnetic field creates a molecular agitation in the water passing
through the field. It is this agitation that alters the effects of calcium and
magnesium carbonates with regard to limescale formation.
Scale either is eliminated completely or is reduced to a
fine powder that easily is wiped away. Soap curds or scum are no longer a major
contributor to bathtub soap scum buildup, dingy looking laundry or a variety of
other undesirable effects. Savings in industrial equipment such as cooling
towers and boilers are substantial. Basically, existing scale is removed and
never formed again.
Depending on the application and water hardness levels, the
benefits include savings in chemicals, maintenance, downtime, energy and
extended life of capital equipment.
The use of catalytic and magnetic devices in the treatment
of water is controversial. Failures of equipment performance in this industry
are not uncommon. Unfortunately, as with any new and relatively inexpensive
technology, there are those who ride the profit wagon. These entities often
make false product claims and never cease to amaze the industry with their
creativity and devotion to generate sales. No industry or product is insulated
from this phenomenon. Throughout its history, the water improvement industry
certainly has fallen prey to wild marketing tactics and false promises
including the manufacturing, marketing and sales of water treatment devices.
To date, there are no standards on the technology with the
Water Quality Association or NSF. Perhaps someday there will be a standard from
an accredited association from which manufacturers, dealers and customers alike can work from.
Electronic water conditioning cleans up scale and softens water for various applicationscleans up scale and softens water for various applications