The main differences between primary, medium, and high-efficiency filters

An air filter refers to an air filtration device, generally used in clean workshops, clean factories, laboratories, and clean operating rooms. Based on their working principles, air filters can be classified into primary filters, medium-efficiency filters, high-efficiency filters, and sub-high-efficiency filters. The respective performance levels are as follows: High-efficiency air filters: ■ Suitable for use in normal temperature and humidity conditions; they can filter air containing trace amounts of acids, bases, and organic solvents. These filters feature high efficiency, low resistance, and a large dust holding capacity, and are widely used in fields such as aerospace, aviation, electronics, pharmaceuticals, and bioengineering. ■Ultra-high-efficiency filters with a capture efficiency of ≥99.999% and a particle size range of 0.3–0.1 μm can be manufactured to meet user requirements ； Various non-standard filters and sub-high-efficiency filters (95% ≤ efficiency ≤ 99.90%). The V-type pleated filter is used in general ventilation systems, featuring a large filtering area, low resistance, and a long service life. It can be used as a pre-filter for high-efficiency filters, thereby effectively extending their service life. The DC and DZ types of coarse-to-mid efficiency bag filters use non-woven fabrics of primary and medium efficiency as filter media, with painted cold plates serving as the framework. Used for primary and secondary filtration, these filters offer advantages such as a large dust holding capacity, low resistance, and ease of cleaning. Depending on the operating environment and the materials used, their filter efficiency levels are classified as F5, F6, F7, and F8. They are usually classified by filtration efficiency. Primary efficiency: Low filtration efficiency; generally used for pre-filtering or as the first stage of filtration. Medium efficiency: Moderate filtration efficiency; bag filters are commonly used, though plate filters are also available. High efficiency: High filtration effectiveness; paper filters are used, and there are both types with and without partitions