Abstract
Based on a previously published work, calculations of the minimum plasma gas flow rate for torch tubes of various dimensions have been performed Predicted minimum rates have been verified by experiment It is possible to sustain a discharge at 600 W and 6 L/min without reducing drastically the external size of the torch One of the main parameters in torch design is the various flow velocities The main influence on the plasma gas flow rate is provided by the space between the external and the intermediate tube A practical design is proposed and a comparison is made with the literature