Classification of air conditioning filter types and precautions

There are two types of air conditioning filters, namely dry type and wet type.

Dry type
It is a filter that separates impurities from the air through a dry filter element (such as a paper filter element). The air filters used in light vehicles (including sedans and mini vehicles) are generally single-stage. Its shapes can be flat, round, oval or flat. The filter material is filter paper or nonwoven fabric. The end cover of the filter element is made of metal or polyurethane, and the shell material is metal or plastic. At the rated air volume flow rate, the original filtration efficiency of the filter element should not be less than 99.5%. Due to the harsh working environment, heavy-duty vehicles must have multiple air filters. The first stage is a cyclone pre-filter (such as blade rings, cyclone tubes, etc.), which is used to filter out coarse particle impurities, with a filtration efficiency of over 80%. The second stage fine filter is a microporous paper filter element (generally referred to as the main filter element), with a filtration efficiency of over 99.5%. After the main filter element, there is also a safety filter element, whose function is to prevent dust from entering the engine during the installation and replacement of the main filter element or in case of accidental damage to the main filter element. The material of the safety core is mostly nonwoven fabric, and some use filter paper.

Wet type
It includes two types: oil-immersed and oil-bath. Oil-immersed type separates impurities in the air through an oil-immersed filter element. The filter element materials can be metal wire fabrics or foamed materials. The oil bath type is to introduce the dust-containing air sucked in into the oil pool to remove most of the dust. Then, when the air with oil mist flows upward through a filter element made of metal wire, further filtration is carried out. The oil droplets and the trapped dust return to the oil pool together.

Precautions
Generator set air filter: It is mainly an air intake device that filters particles and impurities in the air drawn in by the piston generator set during operation. It is composed of two parts: the filter element and the housing. The main requirements for an air filter are high filtration efficiency, low flow resistance, and the ability to be used continuously for a long time without maintenance. When the generator set is in operation, if the inhaled air contains dust and other impurities, it will accelerate the wear of the parts. Therefore, an air filter must be installed.
There are three types of air filtration methods: inertial, filtering and oil bath. Inertial type: As the density of particles and impurities is greater than that of air, when particles and impurities rotate or make sharp turns with the air, the effect of centrifugal inertial force can separate the impurities from the airflow. Filtering type: Guide air to flow through metal filter screens or filter paper, etc., blocking particles and impurities and adhering them to the filter element. Oil bath type: At the bottom of the air filter, there is an oil pan. By the rapid rotation of the airflow to impact the oil, the particles and impurities are separated and adhered to the oil. The oil droplets stirred up by the airflow flow through the filter element and adhere to it. When air flows through the filter element, it can further adsorb impurities, thereby achieving the purpose of filtration.

The replacement cycle of the air filter for the generator set: For common generator sets, it should be replaced every 500 hours of operation. The standby generator set should be replaced after working for 300 hours or every six months. When maintaining the generator set on a regular basis, it can be removed and blown with an air gun to extend the replacement cycle by 200 hours or three months.