# Analysis of the Possibility of Using Drill-Type Electrodes for Air Ionization
## 5 Conclusions  
1. Results of air strength measurements in non-homogeneous fields between the drill-type electrodes are similar to results characterizing air strength in electric fields between the needle electrodes.
2. The strength of the air (the value of the breakdown voltage U\({}_{\text{b}}\)) between the drill-type electrodes is higher than that of the needle systems. This difference is more evident in a system with needle electrodes with a larger needle angle generated between the corona electrodes with the cone angle 45\({}^{\circ}\), the difference is between 22% and 27%. In a needle system with electrodes with the 20\({}^{\circ}\) angle, these differences range from 14% to 24%.
3. Diameters of the drill-type electrodes have little influence on the voltage values characterizing the air strength. The scatter of results of drill-type electrodes, depending on their diameter, is: for U\({}_{\text{o}}\) voltage--from 8% to 12%, for sparking voltage U\({}_{\text{s}}\)--from 4% to 7% and for breakdown voltage U\({}_{\text{b}}\)--from 2% to 9%.
4. The ionization efficiency of the electrode system, expressed as the ratio of the initial voltage value of the corona voltage U\({}_{\text{o}}\) to the breakdown voltage U\({}_{\text{b}}\) value, determines at what percentage of the breakdown voltage value the air ionization processes between the electrodes begin. From the point of view of the electrical strength of the air, the higher the corona voltage U\({}_{\text{o}}\) value, the more favorable the system. In technological processes, such as air purification by means of its flow between the electrodes producing a non-homogeneous field (air filters) or ozonization of water or wastewater, the opposite is true. We try to make sure that the purification processes start as early as possible, i.e., at the lowest possible corona voltage U\({}_{\text{o}}\). The lower the corona voltage U\({}_{\text{o}}\) value, the more economically and technically efficient the type of used electrodes. The ionization efficiency of drill-type electrodes is significantly higher than that of the needle electrodes. For a distance of 8, 12 and 16 cm between the drill-type electrodes, the ionization efficiency is 47%, 43% and 41%. For the needle electrodes and for the same distance, the ionization efficiency is 50%, 47% and 50%, respectively, and for needle electrodes with the 45\({}^{\circ}\) needle angle it is 63.3%, 59% and 58%.
5. The results presented above justify the undertaking of future research on models of drill-type systems, which represent large-size real systems, in terms of their ionization efficiency. The research should include the determination of ionization efficiency not only of the models of systems with drill-type electrodes, which reproduce large-size designs of technical systems, but also comparative research, with structural models using classic needle electrodes.  
Conceptualization, J.S. and M.K.; Methodology, J.S.; Validation, M.K., Formal Analysis, J.S.; Data Curation, J.S. and M.K.; Supervision, J.S.; Writing--Original Draft Preparation, J.S.; Writing--Review and Editing, M.K.; Visualization, M.K. All authors have read and agreed to the published version of the manuscript. This research received no external funding. The authors declare no conflict of interest.