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The
conventional
method of controlling scale and biofilm (slime) in building
air-conditioning systems is by chemical dosing, however, the
condenser and cooling tower
still require a routine cleaning schedule. This
method only slows the rate of scale and biofilm buildup with the
result that the systems are always running at less than 100%
efficiency and often considerably less than 100% and with a
constant risk of the
Legionella health problems.
Piping for building cooling systems and hot water systems can be constructed of a variety of materials and vary widely in size from small bore pipes to quite large diameter pipes. Depending on the pipe size, construction material and fluid dynamics, the Scale-X magnetic fluid conditioners may be installed externally to the process piping or internally to the pipes and/or vessels. They are installed at, or just prior to, identified scaling points, usually just before entry to the vessels. The Scale-X MFC is maintenance free. A typical building air cooling system will have more than one scaling point as shown schematically above and may require the application of multiple Scale-X magnetic fluid conditioners, sometimes referred to as magnetic water descalers, to ensure that the required level of magnetic fluid conditioning is maintained throughout the fluid system.
Water supplies contain
diamagnetic mineral salts, the predominate one being
calcium carbonate and this forms scale build ups in
building
cooling water systems and hot water systems at such places as
heat exchangers and cooling tower slats. This is due to
evaporative concentration of the inorganic mineral salts in the
water. The scale is predominately in the form of calcium
carbonate - calcite, the
most common substance treated by magnetic fluid treatment.
Other typical scales in water systems are dolomite, gypsum, lime and
barium sulphate. |
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Scale-X MFC's can totally eliminate the scale and sludge build ups and, depending on fluid velocity and turbulence, it will slowly remove the existing scale. Scale inhibitors can be discontinued reducing the cost and the problems associated with discharge and disposal of dangerous chemicals. The condenser tubes and cooling tower slats stay clean, the sludge and scale stays soft and settles out during low fluid velocity in the basin of the cooling tower or in the clarifier. A month after installation of the MFCs and for the next couple of months the cooling tower slats should be hosed down to remove the softened existing scale until it is totally removed. (Note:- the velocity of the water over the cooling tower slats is too slow to scour away the softened scale). The cooling tower basin should be cleaned on a regular basis to remove the settled sludge. (Note:- when cleaning the cooling tower basin the softened sludge should be hosed out immediately and not allowed to dry as it will harden again if allowed to dry) . A typical
example is contained in the accompanying
International Maintenance Management Conference technical paper
(extract) where magnetic units supplied by PS Australian
Promotions Pty Ltd, the mother company of Magnetic Technology,
manufacturers of Scale-X, were installed. This building air
conditioning system required the condenser tubes to be de-scaled
on average every one or two months during the short Victorian
summer otherwise the air conditioning system would trip out on
high head pressure, the rate of scale and biofilm (slime) build
up was extremely fast. Scale inhibitors were discontinued, and
after installation of the MFCs the air conditioning system
condenser tubes and cooling tower slats did not require
de-scaling again and remained completely clean. The cooling
tower basin was cleaned on a regular basis to remove the settled
sludge.
Another major benefit of installing MFCs is that the number of cycles that the air-conditioning system can operate at can be significantly increased. This allows reduced beed-off and a reduction in water usage. The scale problem can be eliminated from all surfaces, not only in condenser tubes, pipes and cooling towers. Scale problems in valves, pumps, instrumentation, etc.. can also be eliminated. The successful elimination of scale problems in control valves using Scale-X MFC's was the subject of a technical article published in Chemical Engineering in Australia, Newsletter of IE Australia.
By eliminating and/or controlling the formation of scale and
sludge in these fluid process systems, Scale-X MFC's
reduces/removes the nutrients and alters the environment in
which harmful bacteria live. The water stays clean and the
sludge and softened scale settle out in the basin of the cooling
tower or clarifier as explained in the accompanying document on
the
refinery cooling tower. This can result in
the elimination
of the bacteria problem. The use of magnetic fluid treatment in
controlling bacteria is discussed in more detail in
the section
on bacteria, algae and Legionella. The systems should always be
monitored for Legionella to meet government regulations.
in all 29 cooling towers surveyed without the use of biocides.
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