## 3 Results and Discussion

Table 6: Summary of the resistance values \(\Delta_{\text{P}}\) and the K\({}_{2}\) coefficient for individual test variants. \begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Production** \\ **Line** \\ \end{tabular} } & \begin{tabular}{c} **Intervals** \\ **between** \\ **Pulses [s]** \\ \end{tabular} & \begin{tabular}{c} **The Amount** \\ **of Waste** \\ **[kg\(\cdot\)h\({}^{-1}\)]** \\ \end{tabular} & \begin{tabular}{c} **Dust Load** \\ **[kg\(\cdot\)(m\({}^{2}\)min)\({}^{-1}\)]** \\ \end{tabular} & \
\begin{tabular}{c} **Average** \\ **Particle Size** \\ **[\(\mu\)m]** \\ \end{tabular} \\ \hline \hline
\begin{tabular}{c} Line for \\ processing \\ narrow \\ surfaces \\ CNC drilling \\ machines line \\ \end{tabular} & 10,208.2 & 606 & 250 & 0.0133 & 140.88 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Working conditions of bags in industrial installations and results of the dust resistance coefficient K\({}_{2}\). Figure 9: The value of the K\({}_{2}\) coefficient depending on the working time of the bags. of the values obtained in the study on wood dust filtration [30]. In these tests, however, a filter material with a higher weight was used and the intervals between the cleaning pulses were much smaller. In other works describing the filtration tests, taking into account the determination of the K\({}_{2}\) coefficient value, mineral dusts were usually used. [PERSON] [35] calculates the dust resistance coefficient for fly ash with three different values of the geometric mean diameter (dust from: power plant 19.15 \(\upmu\)m, fluidized bed combustion 45.68 \(\upmu\)m and paint incinerator 37.55 \(\upmu\)m). This dust is much finer than wood dust, hence the K\({}_{2}\) coefficient values are much higher and range from 120,000 s\({}^{-1}\) to over 300,000 s\({}^{-1}\). [PERSON] et al. [25]. [PERSON] and [PERSON] [24] dealt with, inter alia, filtering separation of limestone dust. For this type of dust, at a similar filtration velocity, the values of the K\({}_{2}\) coefficient are also much higher than for wood dust. Moreover, the study of the filtration of limestone dust and fly ash carried out by [PERSON] and [PERSON] [24] showed a directly proportional increase in the K\({}_{2}\) coefficient depending on the filtration velocity. [PERSON], et al. [25] came to similar conclusions. The study on the K\({}_{2}\) coefficient during the filtration of coal dust was carried out by [PERSON], et al. [28]. In this case, the focus was on the influence of dust humidity on the filtration resistance caused by the dust cake and the K\({}_{2}\) coefficient. The test carried out at similar velocities showed that the value of the K\({}_{2}\) coefficient reaches up to about 1.3 \(\times\) 10\({}^{8}\) and is definitely higher than in the case of filtering wood dust. It is also highly dependent on the moisture content of the dust. Studies on the K\({}_{2}\) coefficient during filtration, as a rule, concerned research based on mineral dusts. In the available publications, one can also find works on organic maize and tapioca dust in comparison to mineral dust in the form of phosphate concentrate [36]. The research concerned the porosity of the dust cake formed on the filter surface. The results obtained clearly indicate that the porosity of the dust cake depends, inter alia, on the particle size (the smaller the particle size, the lower the porosity, and the higher the cake density) and the filtration velocity. Therefore, a directly proportional increase in the K\({}_{2}\) coefficient was shown depending on the increase in the density of the dust cake and inversely proportional to its porosity. The effect of increasing the filtration velocity on the value of the K\({}_{2}\) coefficient during filtration has also been proven. The values of the K\({}_{2}\) coefficient obtained for individual dusts at the filtration velocity of 5 m\(\cdot\)s\({}^{-1}\) were: 74,000 s\({}^{-1}\) for tapioca dust, 16,000 s\({}^{-1}\) for corn dust and 23,200 s\({}^{-1}\) for phosphate concentrate dust.