Cleaning and De-oiling of Machine Parts with Low-pressure Flashing Flow
Sachiyo HORIKI*, Tsugue ITOH* and Masahiro OSAKABE*
Usually, Trichloroethane has been used for the de-oiling and the 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. As one of the physical method, a cleaning by a steam flow in a packed bed of machine parts was proposed. In the previous study, the saturated or superheated steam of 150〜270℃ was used. Actual rivets of different sizes were used in the de-oiling experiment. In the steam of high pressure and high temperature, it was successful to remove the off from the machine parts in a few minutes. In the present study, the low-pressure flashing flow was applied to the packed bed of machine parts. The temperature and pressure of the flashing flow were less than 100℃ and atmospheric pressure, respectively. In this condition, vaporization of oil is considered to be negligible.
Key words: De-oiling, Machine parts, Love pressure Dashing Dove, Physical cleaning,
Usually, trichloroethane has been used for the de-oiling and cleaning of machine parts. The de-oiling and the cleaning, such as removing the cutting oil and the anticorrosion oil from machine parts, are important manufacturing process. But, its production and import have been prohibited since 1995 because of its possibility to destroy the ozone layer. For the earth environment, the machine parts cleaning has to be done with the physical method than the chemical method. We proposed the physical method using the steam flow. In the previous study, the high pressure steam of about 0.6〜0.8 MPa was applied to the rivets packed in a container. The de-oiling and washing were successfully done by steam in a few minutes. It was also able to remove the tough oil that can't remove by the chemical method. But this method needs a large amount of heat and the sturdy device because of using the high temperature and high pressure steam flow.
In the present study, de-oiling of machine parts by the saturated steam less than 100℃ was studied. And isoenthalpic method to predict the characteristics of low pressure flashing flow in non-spherical particle bet was proposed.
p: pressure (Pa)
D: typical length of rivets (m)
ρ: density (m3/kg)
h: enthalpy (kJ/s)
u: velocity (m/s)
m: mixture of two-phase
2. Experimental apparatus and procedure
Shown in Fig.1 is a schematic diagram of the experimental apparatus. The apparatus consist of a cylindrical container and a drain tank which were made of transparent acrylic resin for the observation of flow pattern. The pressure in the test section was under the atmospheric pressure by the vacuum pump. The test hot water was provided by a hot water boiler and through the turbine flow mater and two nozzles for the pressure reduction. Then it produced two phase flashing flow (saturated steam and water) in the test section.