Dry air filter is mainly used for drying compressed air and filtering. After the compressed air from the compressor is not out of pure. This is because the air compressor itself contains oil, during the compression work, there must be some oil mixed into the compressed air to go. Another nature of air itself contains a number of solid particles and moisture, etc., when used directly in the pneumatic circuit that without purification of gas, will bring some pneumatic circuit failure, damage to the pneumatic components, reducing component life, production efficiency decline, and even cause accidents.