| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2005: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2004: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
A simple model of charge injection type of electrostatic oil filter was made which consists of two smooth plate electrodes and an emitter electrode, which has sharp projections on its both surfaces in order for electric charges to be injected under the application of a high DC voltage. The effects of various factors such as the configuration of emitter electrode, the magnitude and polarity of applied voltage, flow rate and physical properties of oils on the filtration speed were investigated using 18 types of oils, in which a test powder was mixed at a fixed concentration. The filtration speed was increased by virtue of charge injection for the majority of the oils used; for a few oils, the filtration speed was hardly changed by using the emitter electrode ; in addition, the filtration speed was decreased to some degree for a few oils by charge injection. The filtration speed was increased with increasing number of sharp projections, with decreasing electrode spacing and emitter thickness, with increasing applied voltage and flow rate, but the filtration speed tended to be saturated or was, in some cases, decreased. An ion drag flow generated from the tips of the projections towards the smooth plate electrodes might detach particles captured on the plate electrodes for some oils under such conditions as relatively large applied voltage or small electrode spacing. The experiments showed that there was no correlation between the viscosity of oil and the filtration speed but that a weak correlation exists between the conductivity of oil and the filtration speed. The filtration speed of oils having relatively high conductivities was slower than that of oils having relatively low conductivities. No correlation was found out between the physical properties of oils and the degree of the increase in the filtration speed under charge injection.
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