## 2 Model and Experimental Research  
### Possibilities of Organizing Dust Extraction Process from Multi-Cyclone Filters  
As experience so far has shown, the main reason for the suction streams' unevenness from the cyclones may be the differentiation of the pressure drop differentiation of these streams in the filter settling tank and on the cyclone-suction stub section, for individual cyclones. This results mainly from the unequal lengths of the above-mentioned sections, determined by the cyclone position in relation to the suction nozzle and the impact of the settling tank walls on the suction streams from cyclones located in their vicinity, as well as the possible presence of turbulence areas in the total suction stream from the settling tank. In the theoretical and experimental studies [18; 21; 42; 43], three basic methods were proposed to obtain a relative uniformity of the suction streams from individual cyclones:  
* maintaining the symmetry of all cyclones' positions in relation to the suction nozzle;
* creating equal pressure drops for suction streams through appropriate outflow throttling from those cyclones for which the pressure drop is lower than the remaining ones;
* a combined method consisting of an appropriate constructional combination of both of the above-mentioned procedures. The only possibility to obtain position symmetry is to place all the cyclones along the circle circumference--depicted in Figure 6.  
In the central part of circular plate, the more unused area that remains, the greater the number of cyclones that are included in the multi-cyclone. Due to the symmetrical structure of the multi-cyclone with a large number of cyclones, the settling plate on which the cyclones are mounted adopts disproportionately large dimensions. There is usually no excess space in a vehicle's engine compartments, therefore the practicality of this type of multi-cyclone structure is low. The pressure drop equalization of the cyclone suction streams by throttling and directing selected streams can be performed by the following methods:  
* by placing an intermediate inlet to the suction nozzle in the multi-cyclone sedimentation tank;
* by dividing the settling chamber into independent channels;
* by means of throttling elements for the suction stream flow located at the outlets of selected cyclones. As can be seen from the above, the first two methods require special design form development of settling chamber. In the last one, the shape of the settler does not play a decisive role. In any case, however, it is necessary to carry out the complex and repeated experimental studies. An intermediate inlet of suction streams from the cyclones in the dust collector can be created by introducing a shaped partition (deflector) into the sedimentation basin, above the suction stub pipe inlet. It should ensure the desired distribution of the current lines for the suction streams flowing out of the individual cyclones. A proposal for such a solution is shown on the example of an axisymmetric settler--depicted in Figure 7.  
Figure 6: Diagram of the sedimentation basin maintaining position symmetry of all cyclones in relation to the suction stub: 1—cyclone, 2—sedimentation basin, 3—suction pipe stub. The deflector dimensions and shape are selected so that the distances of the individual cyclones from the intermediate inlet differ as little as possible. If, after taking the measurements, it turns out that deflector shape selection does not ensure the same degree of suction from all cyclones, which may be particularly difficult to meet in the case of cyclones located centrally in the multi-cyclone, then the course of the streamline can be corrected by making a bore in the center of the deflector, through which an additional air stream will enter, and thereby \"enhancing\" the suction from the central zone. It should be emphasized that the described design solution is difficult to develop as it requires the use of a complex computational model, as well as complex and time-consuming experimental research.