Earlier this month I attended the CleanTech 2008 Summit and Exhibition in Israel. The trade show focused on renewable energy, conservation technology, and, not surprisingly given the country’s climate and neighborhood, water technologies.
One company that stood out was Hydropath Holdings Ltd. (Hydropath), a British water treatment firm who was exhibiting its technology through its Israeli marketer, Waterpath (itself a division of Pazgas, an Israeli gas company). Hydropath’s technology cleans limescale in commercial, industrial and residential water systems without the use of chemicals by a device that attaches to pipes and generates electric fields in the water flow. According to Hydropath’s web site, 1 mm of limescale deposition can reduce the efficiency of a residential boiler by 10%.
Limescale deposits occur when positively and negatively charged ions such as calcium carbonate and bicarbonate exceed a maximum concentration and crystalize out of solution onto pipe surfaces. Crystallization can be either homogeneous (the initial “seed” crystals are formed by oppositely charged ions of the dissolved substance) or heterogeneous (the initial seed crystals are formed by ions on an alien substance such as a pipe surface). This latter type of crystallization leads to scale deposition on pipes. Homogeneuously-formed crystals, on the other hand, are carried through the pipe without impeding water flow.
Hydropath owns several patents and applications in the U.S. and abroad, including U.S. Patent No. 5,667,677 (677 patent) and two applications, International Pub. Nos. WO 2007/045824 (‘824 application) and WO 2008/017849 (‘849 application).  As described in the ‘849 application, the electric field produced by Hydropath’s device orients the molecules so all of the positively charged ions are aligned and traveling in one direction, and all the negatively charged ions are aligned and traveling in the opposite direction. This increases the odds of collision between particles of opposite charge, and leads to increased growth of the benign homogeneous crystal clusters. It also decreases the saturation level of the solution, so existing limescale deposits can re-enter solution and flow out.
 
The ‘824 application discloses using the electric field to provide a more energy efficient desalination process. The electric current causes water to re-orient into a thin layer of molecules with positive poles on one side and the negative poles on the other side. This “hydration” layer excludes other molecules and contains substantially pure water, which can be extracted using less energy than other desalination methods.
Hydropath’s patented technology has many applications, including boilers, heat exchangers, swimming pools and fuel pipes, and according to the company’s web site, can be used to combat bacteria, algae and other substances in addition to limescale.
