The air filter is the main purification device of the clean room and the main means of air purification. Therefore, it is particularly important to understand and grasp the basic knowledge of clean room design, construction and maintenance manager's filter.

The clean room is divided according to the performance of the air filter (efficiency, resistance, dust capacity), usually divided into primary air filter, medium efficiency air filter, high efficiency air filter, secondary high efficiency air filter, high efficiency. Air filter (HEPA) and ultra-high efficiency Air filter (ULPA) six kinds of filters.

The standard "Air filter" GB/T14295-93 will specify the efficiency and resistance of different filters as follows:

The standard "high efficiency air filter" GB13554-92 stipulates that high efficiency filters are divided into four categories according to their performance: A, B, C and D.

Class D is also known as ultra-high efficiency filters (or 0.1μm high efficiency filters or ultra-low transmittance filters).

The type of air filter: We start from the structure of the air filter, the air filter is divided into two types: dry and wet. The main difference between the two is the difference in materials and principles.

Most air filters are made of paper or non-woven fabrics, which pick up dust particles through the fiber layer of the material; Most air filters are made of wire fabric or foam, and impurities in the air are separated by wet oil. Since cars are often used for drying air filters, the next step is to focus on drying air filters.

An air filter is a device that captures dust in a gas-solid two-phase flow and purifies the gas through the action of a porous filter material. It purifies the air with low dust content and sends it into the room to ensure the process requirements of the clean room and the air cleanliness of the general air-conditioned room.