As the position of successive cyclones moves away from the suction stub pipe, the suction stream values \(Q_{Sc}\) systematically decrease, and for the furthest cyclones they assume values that are lower by 35-50% [26]. The uniform suction stream values from the individual cyclones of a multi-cyclone made of several dozen cyclones can be ensured by using a method that maintains the symmetry of the position of all the cyclones in relation to the suction nozzle, or by a method of creating suction streams that are equal to the resistance by dividing the settling space into independent segments and channels covering a specific number of cyclones. The application of a specific method depends on the number and type of cyclones, space limitations at the place of multi-cyclone installation, and the possibility of carrying out an appropriate scope of tests. This work [29] presents a multi-cyclone design intended to study the minimization effect on suction uniformity of individual cyclones by removing the suction stream method from the separation chamber (dust settler). The multi-cyclone consists of 24 through-flow cyclones with an axial inlet, closed in a rectangular cassette, to which a dust trap is tightly attached at the bottom. Dust extraction from the common settling tank takes place through four separate nozzles, shaped in such a way that they form narrowing channels. The same air flow rate was ensured in each stub pipe. Experimental studies of the multi-cyclone for various suction rates, and with a variable air flow velocity through a single cyclone, showed that for a single cyclone, under comparable flow conditions and the same suction degree, the multi-cyclone separation efficiency would be 5-7% lower [29]. This simple dust removal solution from the settling tank significantly reduces the uneven suction from cyclones but does not completely eliminate it. According to the authors [30], a more effective method of reducing the unevenness of the suction from the cyclones is the multi-cyclone modular structure. The module presented [30] is a cassette with a square cross-section in which there are four symmetrically placed through-flow cyclones with an axial inlet--depicted in Figure 2. A multi-cyclone consists of six such modules, which are arranged in two rows next to each other. The module dust collector has been divided into partitions so that the outlet windows of the individual cyclones are isolated from each other. Each module has a separate settler from which dust is sucked through a centrally located duct. Dust extraction ducts from the six modules are connected into one common collector, from which extraction is performed by one duct. The presented design steps were dictated by efforts to eliminate the interaction of the swirled streams flowing out of the individual cyclones in the module. The performed experimental tests on the module showed that its characteristics did not differ significantly from the characteristics of a single cyclone, both in terms of course and value, which means that the suction from all four cyclones is identical. This means that the pollutants suction method from the dust collector of the module is appropriate. The experimental performance studies of the entire modular multi-cyclone also did not show a decrease in efficiency in relation to a single cyclone. However, due to the use of a rather complex system of suction lines inside the connector, the pressure drop of this multi-cyclone has increased by about 15% compared to a single module. The problem of organizing the suction process and minimizing uneven suction from the settling tank of the radial filter, which is composed of three identical modules, is presented in this work [31].