Traditional filters typically use screens to separate particulate matter from liquids. These screens require frequent replacement and cleaning, otherwise they easily become clogged. In contrast, fish mouths have a much stronger filtration capacity. Filter-feeding fish, such as goldfish, paddlefish, basking sharks, and whale sharks, can retain food particles while filtering food, preventing their oral filters from becoming clogged.
Based on the filtration mechanism of the mouth structure of filter-feeding fish, a high-efficiency filter model was designed to effectively avoid clogging. A 3D-printed cone-shaped nylon plastic filter model was designed. The model was placed in a water flow tank to observe its filtration effect and compared with the filtration mechanism of the paddlefish's oral structure.
The results showed that both the model and the fish's mouth capture particulate matter and prevent clogging by creating eddies in the liquid. The gill arches are cone-shaped structures formed by the bending of hard or cartilage, supporting the gills, with the bones arranged parallel like an old-fashioned radiator.
Researchers explain that the cone-shaped structure facilitates water flow in the fish's mouth, creating currents and eddies, while the parallel-aligned bones help small particles aggregate. The combined effect of these two elements forms a "vortex step filtration" mechanism, which can intercept particles even smaller than the gaps between bones.
This filtration mechanism has wide-ranging future applications, from microfilters filtering particles only the size of cells to filters in large industrial pipelines, where it can function efficiently.
