Principles and methods of designing direct current arc plasmatrons for cutting

Principles and methods of designing direct current arc plasmotrons for cutting are generalized. The necessity to account gas-dynamic factors in designing and conditions of safe plasmotrons application are emphasized. Major factors are summarized, generalized principles and design methods used during engineering of direct current arc plasmatrons for cutting are formulated. It is noted, that the generalized design principles can be classified into three basic groups in which the most important principles are the principles of the achievement of maximal productivity values, reliability and quality of electroplasma processes, as well as safe application of plasmatrons. It is offered to emphasize gas-dynamic design factors defining functional parameters and plasmatrons` safety for metal cutting. Main principles and methods of gas-dynamic design applicable to plasmatron as a whole, and to separate parts of gas-air path are defined. Main principles and methods of acoustic (“safe”) designing, directed on the achievement of a minimum level of aerodynamic plasmatron noise are formulated. Plasmatrons, designed on the basis of the developed principles and methods and having improved parameters of efficiency, quality and safety are mentioned. Constructions designed on the basis of the above principles include a series of one-route arc plasmatrons for metal cutting (PMVR-M, PMVR-2, PMVR-2М) and universal (according to parameters of quality and safety) two-route plasmatrons working according to principles of narrow jet plasma.