Coalescing filters play a pivotal role in filtering invisible oil mist from dirty air streams. Fibrous filters are the most commonly used method in industries such as air compressor systems, automation devices, and clean rooms. When oil mist passes through filter media, Contal et al. (2004) identified four stages during mist filtration: deposition, clogging, filming, and drainage. Kampa et al. (2014) provided a comprehensive view of liquid transportation within filters and propose a phenomenological model called “Jump and Channel Theory” to describe the filter loading process. Chang et al. (2017) demonstrated that arranging a drainage layer influences the saturation rate of each filter layer. However, previous research has focused on the filter media during the loading of oil mist, but it does not account for the changes in filters that have been pleated or assembled into cartridges. Available manufacturing method is much more crucial for the commercial market and mass production. In the market, there are two major types of manufacturing methods: pleat-type and round-type. Therefore, we not only focus on the filter cartridge during loading but also propose a schematic method to improve the performance of coalescing filters. This approach is essential for the industrial market and end users.

In this work, we introduce a new evaluation method and an improved design for coalescing filters, particularly aimed at enhancing their longevity. To compare the two manufacturing structures, we applied a novel loading system (Figure 1a) specifically for assembled filters. The concentration distribution of the challenge DEHS aerosol (Figure 1b) is applied with a loading rate of 3g/hr. Both structures utilize identical single filter media, same size of filter (Figure 2a), and adhere to a uniform 6-layer design. The only different is the inner structure. One is pleat-type filter (Figure 2b). The other is round-type filter (Figure 2c). To further compare the loading performance, the initial performance of pressure drop curve (Figure 3a) and efficiency curve (Figure 3b) are very similar under the same filtration test.

As a result of our study, the loading curves of both structures (Figure 4) demonstrates that ...