Abstract
Usually, Trichloroethane has been used for the de-oiling and cleaning of machine parts. But its production and import have been prohibited since 1995 because of its possibility to destroy the ozone layer. Generally for biological and environmental safety, the de-oiling should be done with the physical method instead of the chemical method using detergent or solvent. As one of the physical method, a cleaning by a flashing water flow through a packed bed of machine parts has been proposed. The hot water was injected and flashed into steam and water in the packed bed kept at the low pressure less than an atmospheric pressure. In the present study, a prototype flashing water cleaner was designed and its de-oiling ability was experimentally investigated with different sizes of bolts and nuts as oily machine parts. The de-oiling ability was strongly affected with the newly-defined non-dimensional parameter consisting of the injection duration, the average kinetic pressure of flashing two-phase flow defined at vacant container flow area and viscosity of oil. The de-oiling rate more than 95 % was successfully achieved at the parameter larger than 24.
