Studies on ozone-zero phenomena in ozone generator and on its reliability progress

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[I. Needle-to-plate electrode system] : The needle-to-plate electrode system was used for the observation of the ozone-zero phenomena. Under the control of discharge in oxygen with the applied voltage of about 4.5 kV and the discharge current of about 1 μA, it took more than two and half months to prepare the condition for the experiments. At the first stage the ozone generation characteristics were generally the same of the conventional characteristics and gradually the characteristics were unstable before the appearance of the ozone-zero phenomena. After through these processes, relatively stable ozone-zero phenomena established in oxygen gas. After the appearance of ozone-zero phenomena, the addition effect of nitrogen gas on the ozone generation was confirmed.[II. Coaxial cylindrical type reactor with an inner rotating electrode] : Long time operation is very important for the industrial ozone production. The ozone concentration gradually decreased with time. One of the purposes of … More our experiments is to study what parameters (or reactions) decide this phenomena and how to control it. In this experiment, discharge was continued for eight hours each day and this operation was repeated about wo months. The ozone concentration was kept near the same level during experiments with a new electrode. The same surface condition of electrode was observed for few days and after that, the ozone concentration decreased dramatically due to some change of metal surface condition. The fluctuation of the ozone concentration between 7-0g/m3 was observed. These situations were observed few days and the ozone production stopped. After the zero ozone concentration was kept for about one hour, 10% nitrogen gas was added for 5 minutes. A few seconds after addition of nitrogen, the ozone concentration recovered again.During rotation of electrode, the discharge area became more uniformly. Different ozone production mode was observed with same input power. It seemed due to the change of the adsorbed layer of the metal surface. The ozone concentration seemed to be influenced on the metal surface condition and didn't stabilize during decreasing nitrogen density on the electrode surface. Nitrogen consumption increased with increasing of rotation speed and it looked about two times more at 600 rpm compared with no rotation. [III. Expanded mesh metal electrode type ozone generator (no ozone-zero phenomena observed here)] : We examined the method using an expanded metal electrode which was sandwiched between the di-electrodes sustained the electric discharge regardless of the fluctuation of supplied voltage and made the ozone generator more efficient. Less