The physical water treatment (PWT) device is defined as a non-chemical method of water treatment utilized for the purpose of scale prevention or mitigation. Three different PWT devices, including permanent magnets, solenoid coil device, and high-voltage electrode, were used under various operating conditions. The present study proposed a bulk precipitation as the mechanism of the PWT and conducted a number of experimental tests to evaluate the performance of the PWT. The results of fouling resistances obtained in a heat transfer test section clearly demonstrated the benefit of the PWT when the PWT device was configured at an optimum condition. The results of SEM and X-ray diffraction methods were obtained to further examine the difference in scale crystal structures between the cases of no treatment and PWT. Furthermore, the surface tension of water samples was measured, and it was found that the PWT reduces the surface tension by approximately 8% under repeated treatment as in cooling-tower applications.
Young I. Cho, SungHyuk Lee, Wontae Kim, and Sangho Suh, "Physical Water Treatment for the Mitigation of Mineral Fouling in Cooling-Tower Water Applications" in "Heat Exchanger Fouling and Cleaning: Fundamentals and Applications", Paul Watkinson, Hans Müller-Steinhagen, and M. Reza Malayeri Eds, ECI Symposium Series, Volume RP1 (2003). http://dc.engconfintl.org/heatexchanger/4