Understanding Cellulose vs. Microglass Filter Media
Filter elements are crucial components in various systems, with their effectiveness often defined by the micron size of particles they can eliminate. However, not all filters with the same micron rating offer the same level of efficiency, largely due to the type of media they are made from.
Defining Media Efficiencies
Efficiency ratings of filter elements typically fall into two categories: nominal and absolute. Nominal ratings gauge filtration effectiveness based on the weight of solid particles removed. However, filters with nominal efficiency ratings lack a maximum pore size specification, potentially permitting larger particles to pass through and cause system damage. Conversely, absolute ratings are based on media with uniform pore sizes, ensuring only particles below a specific size can traverse the pores.
Comparing Cellulose and Microglass Filter Media
Cellulose, primarily derived from wood pulp and cotton, is a commonly used media in industrial applications. However, due to its uneven pore size distribution and organic nature, cellulose filters can degrade and undergo structural changes at elevated fluid temperatures. Consequently, they are often rated for nominal efficiency since they may allow larger particles to pass through, risking system contamination.
In contrast, microglass filter media comprises inorganic glass fibers with uniform diameters smaller than those of cellulose fibers. This uniformity enables microglass filters to capture and retain a greater volume of particles compared to cellulose filters. Consequently, microglass elements receive absolute efficiency ratings, marking them as a premium alternative to cellulose due to their efficacy and predictability.
Considerations When Upgrading from Cellulose to Microglass
Transitioning from cellulose to microglass filter elements requires attention to system cleanliness. Initially, a microglass element may experience a temporary reduction in lifespan as it works to improve the ISO cleanliness codes by removing fine particles that passed through previous cellulose filters. However, once the system achieves optimal cleanliness, microglass elements can last 4-5 times longer than the cellulose counterparts they replace.