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ACS statement |
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Buyer
Beware!
David
Hasaon. and Dan BramBon Magnetic
"treatment" consists of passing potentially-scaling water through a magnetic field. Sizing is
based primarily on the water flow rate. The intensity of magnetic fields of
research and industrial devices range from 100 -10,000 gauss. Exposure times are a few
seconds. Promoters
of magnetic devices claim that this simple operation provides a scale-control
method, even for waters having a marked scaling tendency. It is asserted that magnetic treatment can
prevent, or markedly reduce, the amount of scale precipitated. Moreover, it is said that precipitate
morphology is altered. Any deposit
accumulating on a surface is said to precipitate in the form of an easily-washable
sludge rather than a tenacious incrustation.
It is also often claimed that magnetic exposure can inhibit corrosion. The intense controversy regarding the effectiveness of magnetic water treatment devices has a long history (Cowan and Weintritt, 1976). Currently, there is a revival of the controversy and renewed interest, stemming apparently from favorable reports published in the Russian literature (Hibben, 1973; Troup and Richardson, 1978; O'Brien, 1979). The present work was initiated as a result of an aggressive promotion drive of magnetic treatment in Israel by a representative of a U.S. company. This led Mekorot, the national water supply authority, to sponsor tests of magnetic devices under well-controlled laboratory conditions. The
effectiveness of commercial magnetic devices in suppressing CaCO3
scale deposition was investigated in a system consisting of a cast iron pipe
through which hard water flowed at ambient temperature. The effect of magnetic exposure on scale
suppression was evaluated from measurements of the rate of deposit growth, the
extent of the induction period, and the adhesive nature of the incrustation. Conclusions:
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