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Tumble drying of textiles is associated with mechanical and thermal stress, which leads to textile damage and shedding of fibers. In this study, fiber shedding from cotton textiles is investigated by evaluating the mass of fibers accumulated on different filters positioned downstream of the tumble dryer drum. The total mass of fibers at the end of drying was positively correlated with the dry mass of the loaded textiles. By observing the time-dependent accumulation of fibers on a high-performance filter, three different phases of fiber shedding could be identified. In the first phase, which lasted up to a textile moisture content of about 35%, only minimal fiber accumulation was detected. The following phase lasted almost until the end of drying and showed the highest fiber accumulation rates. In the last phase, the rate of fiber accumulation decreased. The experiments also showed that longer tumbling of textiles with a lower moisture content led to a greater total mass of accumulated fibers. To reduce fiber shedding, damage to the textiles and the resulting pollution, it is recommended to reduce the mechanical loading of textiles, especially in the final stages of the drying process.

Tumbling Multi-Chamber (TMC) gear pump is a generally unknown type of hydraulic device, which features a unique three-dimensional shape of the gears. The main benefits of such design over the conventional gear pumps are self-adapting tightness of the pump parts, the possibility to mold the parts from a polymer material and high volumetric efficiency, considering the simplicity of the design. The specific working principle of TMC pumps requires a slightly different approach to the numeric modeling and analysis process compared to the conventional gear pump types (e.g. external gear and gerotor pumps). One of the main contributions of the work is the development of an analysis procedure, which allows studying flow and pressure conditions in the TMC pump. This includes the influence of the positioning of the pump parts on spatial and temporal variations in sealing regions and the influence of pressure field propagation in relation to the valve plate position.