Heyi's primary filters are usually used for primary filtration in air conditioning and ventilation systems, as well as for simple air conditioning and ventilation systems that only require simple filtration. They are mainly used to remove pollution from the air, increase the proportion of return air in the room, and reduce energy loss in heating and cooling.

This device not only serves the purpose of purification, but also protects the next level filters and the system itself from damage. In places where air purification cleanliness requirements are not strict, it is mainly used to capture particles of 1-5 μ m dust and various suspended solids. It is widely used in various air conditioning equipment and systems, as well as for intermediate protection of multi-stage filtration systems. The outer frame materials of this device include aluminum alloy, galvanized steel plate, and can also be made frameless; The filter material is mainly non-woven fabric.