## 2 Materials and Methods
### Airflow Resistance  
To thoroughly investigate the phenomenon of shaping the airflow resistance through the filter layer, we first needed to determine the airflow resistance through the non-dust-loaded non-woven fabric. To this end, clean air was passed through the filter material at a gradually changing velocity. By gradually changing the position of the regulation valve, the flow rate was changed, which caused changes in the filtration velocity during the experiment, and the flow resistance was determined at various airflow rates. These velocities gradually increased and gradually decreased in the second part of the experiment. This made it possible to determine the airflow resistance through the filter material not loaded with dust (\(\Delta\)p\({}_{0}\)). Based on the results of this experiment, the K\({}_{0}\) coefficient of clean material resistance was calculated, which is a constant value characteristic for given filter material. This coefficient is also a linear coefficient of the function of resistance dependence on the filtration velocity. These dependencies are described by formulas (1) and (2). \[\Delta\)p\({}_{0}=\) K\({}_{0}\)w\({}_{\mathrm{f}}\), (1)  
where:  
\(\Delta\)p\({}_{0}\)--resistance of clean filter fabric. K\({}_{0}\)--clean bag filtration resistance coefficient, which is a linear coefficient of the function describing the evolution of the clean bag filtration resistance, shown in the diagram. w\({}_{\mathrm{f}}\)--filtration velocity m\(\cdot\)s\({}^{-1}\). We, therefore, determine coefficient k\({}_{0}\) from dependencies:  
\[\mathrm{K}_{0}=\Delta\)p\({}_{0}/\)w\({}_{\mathrm{f}}\), (2)  
Determining the resistances of the dust-free filter materials is necessary to determine the resistances of the dust layer, which ultimately allows the calculation of the dust resistance coefficient K\({}_{2}\). After determining the resistance to clean airflow through the filter layer, wood dust was added to the experimental stand air circulation. For this purpose, a dust feeder and a regeneration impulse control system were launched. The test was carried out under strictly controlled conditions described in Table 4.  
During the tests of the filtration process, measurements of the maximum airflow resistance before the regeneration impulse were made. The regeneration pulses entering the filter bag through the blowing nozzle were supplied with compressed air at a pressure of 0.5 MPa and occurred at five-minute intervals. This allowed for drawing a curve for shaping the airflow resistance during the experiment. Based on individual curves' regression equations, \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Unit** & **Parameter Value** \\ \hline Maximum airflow speed in the fan duct w & m\(\cdot\)s\({}^{-1}\) & 4.290 \\ Average speed \(w_{sr}\) = 0.85w & m\(\cdot\)s\({}^{-1}\) & 3.646 \\ Air volume flow V & m\({}^{3}\cdot\)s\({}^{-1}\) & 0.0286 \\ Air-to-cloth ratio f & m\({}^{3}\cdot\)h\({}^{-1}\) & 103 \\ Filtration velocity w\({}_{\mathrm{f}}\) & m\(\cdot\)s\({}^{-1}\) & 145.8 \\ Inlet dust concentration & kg\(\cdot\)m\({}^{-3}\) & 0.01 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Filtration parameters during testing of filtration non-wovens. the maximum airflow resistance value in the final phase of the study \(\Delta\)p\({}_{\rm C}\) was calculated. The results obtained during the study were prepared in the form of graphs. Obtaining the value of the resistance of the dust-free filter material \(\Delta\)p\({}_{0}\) and the total resistance during the filtration process, \(\Delta\)p\({}_{\rm C}\), made it possible to calculate the resistance of the dust layer \(\Delta\)p\({}_{\rm P}\) accumulated on the filter material. It was calculated based on formulas (3) and (4).