## 2 Materials and Methods
### Test Stand  
The filter bags used in the furniture factory were tested to determine the airflow resistance using the pilot-scale test stand for the phenomena of the filtration processes (Figure 2). The technical capabilities of the stand allow for the determination of the basic operational properties of the bags in conditions similar to the real ones prevailing in industrial filters. The equipment of the stand allows for creating the test conditions of individual devices, measurement, and control systems included in its composition:  
* Dust dosing system.
* Regulating valve to regulate the volumetric output of the fan of the main air circulation.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Unit** & **Parameter Value** \\ \hline Factory installation & & No. 1—Main pipeline & No. 2—p Auxiliary pipeline \\ identification & & Filter no. 3—SBF-140-5,0S-1A \\ Factory labeling of the filter & & 144.3 & 34.4 \\ Pipeline length & m\(\cdot\)s\({}^{-1}\) & 24 & 26.5 \\ Air velocity in the pipeline & m\({}^{3}\cdot\)h\({}^{-1}\) & 55,450 \\ Far demand & m\({}^{3}\cdot\)h\({}^{-1}\) & JK-90 MT (1 pcs) \\ Fan type & & 60,000 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Basic technical parameters of the dust-extraction installations.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Unit** & **Parameter Value** \\ \hline Number of bags & pcs & 140 \\ Bag length & m & 4.68 \\ Bag diameter & m & 0.15 \\ The area of the working surface of the bag & m\({}^{2}\) & 2.205 \\ The total working surface area of the bags in & m\({}^{2}\) & 313.166 \\ the filter & & 4.918 \\ Filtration velocity, & cm\(\cdot\)s\({}^{-1}\) & 250 \\ The amount of dust generated during & kg\(\cdot\)h\({}^{-1}\) & 250 \\ processing & Dust load & g\(\cdot\)m\({}^{-3}\) & 4.509 \\ The interval between the regeneration pulses & s & 606 \\ for one bag & & \\ The number of shifts in the work of the bag & & 3 \\ during the day & & \\ Estimated number of regenerative impulses & & 143 \\ per day & & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Basic technical parameters of the filter baghouses.  
* A system that controls the frequency of cleaning pulses.  
To register the basic quantities related to the filtration process, installed measuring systems allow one to determine:  
* Airflow resistance.
* Airflow rate in the entire measuring system.  
Figure 2: Test rig set-up; 1—filtration chamber, 2—filter bag, 3—supporting cage, 4—Venturi tube, 5 –dust feeder DSK-I-04p (HYDRAPRESS), 6—dust inlet tube, 7—clean air chamber, 8—tube with cleaning nozzle, 9—compressed air tank, 10—controlling control device, 11—outlet tube, 12—Pranddl tube, 13—differential manometer for air velocity control type MPR-1 (ZAM Kety, Poland), 14—regulation valve, 15—main fan, 16—differential manometer for pressure drop measurements CMR-10A (ZAM Kety, Poland).  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Unit** & **Parameter Value** \\ \hline Bag producer & & Filterpol \\ Fabric type/symbol & & FP-PB400 PS2 Poliester with copper fiber \\ Material weight & g\(\cdot\)m\({}^{-1}\) & 400 \\ Material thickness & mm & 1.8 \\ Tensile strength—lengthwise & daN\(\cdot\)5 cm\({}^{-1}\) & 160 \\ Tensile strength—across & daN\(\cdot\)5 cm\({}^{-1}\) & 110 \\ Breaking elongation—lengthwise & \% & 25 \\ Breaking elongation—across & \% & 25 \\ Strain under stress 50 N—lengthwise & \% & 2.5 \\ Strain under stress 50 N—across & \% & 5.0 \\ Air permeability & dm\({}^{3}\cdot\)min\({}^{-1}\cdot\)dm\({}^{-2}\) & 220 \\ Surface finishing & & Thermal stabilization, calendering, honing, water- and oil-resistant treatment. \\ Electrical resistance & W & \(10^{6}\) \\ High-temperature resistance & \({}^{\circ}\)C & Constant temperature 140, short-term temperature 150 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Basic technical properties of the filter bags according to the manufacturer (material A).