is a kind of thermal cleaning machine and consists of a retort filled with aluminum oxide fluidized by compressed air and wound by electrical heater.
Here, Fluidized bed means, like a liquid, the smooth movement of solid particles by compressed air with constant pressure. Therefore, Fluidized bed inside always keeps the constant pressure and temperature and so it makes 100% perfect cleaning results possible.
Electrical heaters transfer the heat to aluminum oxide particles which are the heat transfer medium and these particles are moved by compressed air and at same time, particles also heat its surrounding air. The hot air heated in this way burns the organic residues such as polymer, contaminated on the parts to be cleaned. Here, the function of aluminum oxide particles is only for heat transfer and its low velocity is only 600 – 800 mm/min. Therefore, no damage even to delicate parts.
The cleaning temperature of retort inside is depended on the kind of polymer and typical cleaning temperature is 420 ℃ – 500℃. After the temperature of retort inside reaches to the setting temperature, the parts to be cleaned are put on the basket specially designed and the basket is immersed into the hot fluidized bed retort. Now the thermal cleaning process is started.
During the cleaning process, all organic residues such as polymer removed by thermal oxidation and become the off-gas without melt and the off-gas is come out by exhaust blower. Very few of aluminum oxide particles may come out with off-gas, but the particles are collected by a sand trap and are reused again. Therefore, the aluminum oxide can be used over for 10 years without a loss. However, the off-gas makes the air-pollution and so sent to the afterburner.
The integrated thermal afterburner is consisted of a combustion chamber and a cooling tower.
The off-gas is burnt and cracked around 900°C – 1100°C while passing the combustion chamber. The cracked off-gas is very hot and so it must be cooled down to 80°C by cooling water according to the regulation.. The safe clean air is emitted into the atmosphere.
