## 3 Results and Analyses
In the case of material B, from 0 to 272 days, it increased from 6412.031 s\({}^{-1}\) to 10,128.94 s\({}^{-1}\), and its increase was close to linear. The K\({}_{2}\) dust layer resistance coefficient for material A was slightly different. However, the overall resistance systematically increased. The K\({}_{2}\) coefficient for material A increased from 0 to 275 days at a level of 240 to 18635. The extension of the service life to 382 days increased the K\({}_{2}\) coefficient to the level of 20,594 s\({}^{-1}\). The differences in the physical properties of nonwovens are noteworthy. The properties of the non-woven fabric made of material A are described in Table 3. In the previously tested non-woven fabric made of material B [28], we can note its much lower tensile strength values along (40 da\(\cdot\)N\(\cdot\)5 cm\({}^{-1}\)) and across (50 da\(\cdot\)N\(\cdot\)5 cm\({}^{-1}\)) and higher air permeability (250 d \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Period**} & \multicolumn{2}{c}{**MATERIAL A**} & \multirow{2}{*}{**Period**} & \multicolumn{2}{c}{**MATERIAL B**} \\ \cline{2-2} \cline{4-6}  & \(\Delta\)**p\({}_{\text{P}}\) [Pa]** & \(\text{K}_{2}\) [s\({}^{-1}\)]** & & **[Days]** & \(\Delta\)**p\({}_{\text{P}}\) [Pa]** & \(\text{K}_{2}\) [s\({}^{-1}\)]** \\ \hline
0 & 1.18 & 240.7 & 0 & 36.852 & 7489.1 \\ \hline
85 & 57.54 & 11,694.2 & 67 & 47.922 & 9738.8 \\ \hline
146 & 63.90 & 12,985.0 & 133 & 53.302 & 10,832.1 \\ \hline
275 & 91.70 & 18,635.5 & 272 & 56.862 & 11,555.6 \\ \hline
382 & 101.34 & 20,594.2 & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Summary of dust layer resistance values for individual test variants and the dust resistance coefficient. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Period [Days]**} & \multicolumn{2}{c}{**MATERIAL A**} & \multirow{2}{*}{**Period [Days]**} & \multicolumn{2}{c}{**MATERIAL B**} \\ \cline{2-2} \cline{4-6}  & **Equation** & \(\Delta\)**p\({}_{\text{C}}\) [Pa]** & & **Equation** & \(\Delta\)**p\({}_{\text{C}}\) [Pa]** \\ \hline
0 & y = 29.889 T\({}^{0.0939}\) & 42.63 & 0 & y = 54.642 T\({}^{0.109}\) & 88.53 \\
85 & y = 62.972 T\({}^{0.0998}\) & 98.99 & 67 & y = 61.827 T\({}^{0.1053}\) & 99.60 \\
146 & y = 65.473 T\({}^{0.1035}\) & 105.34 & 133 & y = 66.455 T\({}^{0.0995}\) & 104.98 \\
275 & y = 89.023 T\({}^{0.0836}\) & 133.15 & 272 & y = 72.250 T\({}^{0.0879}\) & 108.54 \\
382 & y = 95.833 T\({}^{0.0814}\) & 142.79 & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Summary of regression equations and resistance values for the 50 th filter cycle. The obtained results indicate that the type of filter material used plays a vital role among the factors influencing the filtration resistance in a dedusting installation. For the tested installation, bags made of material B are characterized by lower values of the dust resistance coefficient during long-term use. The research on the behavior of various filter nonwovens under the same conditions of use with the same dust has already been the subject of study. [PERSON], [PERSON], [PERSON], and [PERSON] [34] tested three different filter materials: Two nonwovens Polyimide (PI) and Polyphenylensulfide (PPS), a single polymer (PI), and Teflon-laminated (membrane) Polyester needle felt. The nonwovens were tested for the filtration of limestone dust with a density of 2700 kg\(\cdot\)m\({}^{-3}\). The phenomenon of dust layer formation on the surface of filtration nonwovens was investigated, disregarding filtration resistance. Similar studies with phosphate rock were conducted by [PERSON], [PERSON], [PERSON], and [PERSON] [25]. They investigated issues related to the influence of the filter fabric on the formation of a dust layer. The research consisted of determining the experimental strength of the dust layer adhesion on the surface of various filter materials under the same filtration conditions. Acrylic, polypropylene, and polyester non-woven fabrics were tested.