Precision filters for air compressor systems – essential for downstream purification. How to choose and maintain them?

Thread Content

Working principle of the filter: The filter element is composed of materials such as fibrous media, filter screens, and sponge. Solid and liquid particles (droplets) in compressed air are intercepted by the filtering material and accumulate on the surface of the element (both on the inside and outside). The droplets and impurities that accumulate on the element’s surface settle to the bottom of the filter due to gravity, and are then removed either through an automatic drainage system or manually. Material of the filter 1. Housing: stainless steel or PP ； 2. Filter element material: Environmentally friendly special fibers of series B and C, non-woven fabric ； Series D, activated carbon. Filter rating: The classification of filter ratings is based on ISO8573 standards, taking into account the size of solid particles in compressed air after filtration, the amount of liquid water, as well as the levels of oil droplets, oil mist, and oil vapor. Grades are determined based on the filter element (different suppliers use various symbols to denote filter grades; here C/T/A/H are used). The main pipeline filters of grade C can remove a large amount of liquid as well as solid particles larger than 3μm, achieving a minimum residual oil content of only 5ppm; there is also a small amount of moisture, dust, and oil mist. Used in air compressors, after the rear cooler and before other filters, for general protection; used before cold dryers as a pre-treatment device. Air line filter: T-grade air line filters are capable of removing liquid and solid particles as small as 1μm, achieving a minimum residual oil content of only 0.5 ppm, along with trace amounts of moisture, dust, and oil mist. Used for pre-treatment before Class A filters; it further improves air quality after cold dryers and desiccators. Ultra-high efficiency oil removal filter, Class A: This ultra-high efficiency oil removal filter is capable of filtering out liquid and solid particles as small as 0.01μm, achieving a residual oil content of only 0.01ppm; almost all moisture, dust, and oil are removed. It serves as a protective layer before H-grade filtration and desiccators, and after the cold dryer to ensure that the air is free of oil. The activated carbon filter H can remove oil mist and hydrocarbons as small as 0.01μm, achieving a minimum residual oil level of only 0.003ppm; it contains no moisture, dust, or oil, and is odorless and tasteless. It serves as the final filtration stage for businesses that require high-quality compressed air, such as the food industry, respiratory equipment, and aseptic packaging. Class C Precision Filter: General application: Pre-filter for conventional reciprocating air compressors. Material: Multi-layer glass fiber filter elements. Particle size filtered out: 5 MICRON. Oil content filtered out: 5 PPM. Maximum pressure: 16 KG/CM. Maximum temperature: 65°C. Normal pressure drop: 0.2 KG/CM. Maximum pressure drop: 0.7 KG/CM. Function: Filters out large amounts of oil and gas in compressed air to levels of 5 PPM, as well as impurity particles down to 5 MICRON.

Class T Precision Filter: General application: Pre-filter for conventional screw air compressors. Material: Multi-layer glass fiber filter elements. Particle size filtered out: 1 MICRON. Oil content filtered out: 0.5 PPM. Maximum pressure: 16 KG/CM. Maximum temperature: 65°C. Normal pressure drop: 0.17 KG/CM. Maximum pressure drop: 0.7 KG/CM. Function: Removes oil and gas from compressed air to levels of 0.5 PPM, and filters out impurity particles to sizes below 1 MICRON.

Class A Precision Filter: General application: Post-filter for conventional air compressors. Material: Multi-layer glass fiber filter elements. Particle size filtered out: 0.01 MICRON. Oil content filtered out: 0.01 PPM. Maximum pressure: 16 KG/CM. Maximum temperature: 65°C. Normal pressure drop: 0.275 KG/CM. Maximum pressure drop: 0.7 KG/CM. Function: Precisely removes trace amounts of oil and gas from compressed air to levels of 0.01 PPM, while also filtering out impurity particles to 0.01 MICRON, thereby producing high-quality compressed air free of oil.

Class H Precision Filter: General application: Designed for highly precise filtration. Material: Activated carbon filter elements. Particle size filtered out: 0.03 MICRON. Oil content filtered out: 0.003 PPM. Maximum pressure: 16 KG/CM. Maximum temperature: 65°C. Normal pressure drop: 0.75 KG/CM. Maximum pressure drop: 0.7 KG/CM. Function: Used to remove ozone, extremely fine oil and gas particles, and ultra-fine particles from compressed air.

Precautions for installing filters: (1) The operating pressure must not exceed the maximum pressure specified by the filter; (2) Filters should generally be installed after the after-cooler and air storage tank, as close as possible to the point of use and at the lowest temperature. (3) The filter should not be installed after a quick-opening valve, and it should prevent backflow and shock phenomena. (4) The filter should be installed vertically, with sufficient space below it for replacing the filter element. (5) Larger filters should be properly supported within the pipeline.