Plasma Jet is a private company developing and applying plasma technologies based on the method of DC arc jet. Passage of direct current through the gas causes its ohmic heating up to temperatures of 12,000 K. At such high temperatures the gas transforms into a partly ionized state called plasma.
In the case of the DC arc jet method, plasma is formed between the hot cathode and the cylindrical nozzle as the anode. The jet of plasma is emitted from the nozzle with speeds measured in km/s.
Since the heat content of the jet goes up to 20 MJ/kg of gas, this plasma jet serves as a large heat reservoir capable of melting anything injected into it, as well as for the activation of chemical reactions.
Basic advantage of PJ torch vs conventional plasma torch:
-ascending voltage-current characteristics
-more favourable curren-voltage regime (higher voltage, lower current)
-higher thermal eficiency (70-74%)
-plasma plume without turbulence and eddies
-more homogeneous temperature and velocity distribution
-higher plasma velocity ( 1600-1800 m/s at distance of 60 mm from anode nozzle exit!)
a) Conventional torch- F4 Metco
b)PJ-100 torch
Photograph a) is taken from: G. Berbezat, K. Landes, et al., Sulzer Tecnical Reviw 4/99, p.32-35
M.Vilotijevic et al, Velocity and texture of a plasma jet created in a plasma torch with fixed minimal arc length, Plasma Sources Science and Technology, 18 (2009) 015016