Freeze drier is according to the principle of freezing and dehumidification, the compressed air is forced through the evaporator for heat exchange and cooling, so that the gaseous water and oil in the compressed air through isovoltage cooling, condensation into liquid water and oil, and with dust, through the automatic drain discharge system, so as to obtain clean compressed air.

The adsorption dryer is through the "pressure change" (pressure change adsorption principle) to achieve the drying effect. Because the ability of the air to hold water vapor is inversely proportional to the pressure, the dry part of the air (called regas), pressure expansion to atmospheric pressure, the expansion air more dry, and then let it through the unconnected air regeneration desiccant layer (which has absorbed enough water drying tower), the dry water in the desiccant, take it out of the dryer to achieve the purpose of dewetting.