METHOD AND DEVICE FOR TREATMENT OF DISPERSED THERMOPLASTIC MATERIALS BY INDUCTIVELY COUPLED PLASMA Russian patent published in 2002 - IPC

FIELD: low-temperature plasma treatment of materials; production of thermoplastic microspheres for various industries. SUBSTANCE: method involves introduction of material in direction of plasma flow into its area abutting against external side of plasma generator outlet. Working gas flow of stable pressure and flowrate is produced across plasma generator section. Material is fed at speed reducing towards motion of plasma flow. Device implementing said method has cooled discharge chamber placed in case in the form of cylindrical tube, gas-distribution unit mounted at chamber inlet and forming with the latter annular channel, and feeder delivering material to high-temperature region of gas flow. Gas-distribution unit is, essentially, cooled cylindrical insert mounted on plasma generator shaft for displacement along the latter; insert has concave conical outlet end with vortex angle α found from condition 90^°≤ α ≤ 120^°. Insert is concentrically mounted in cavity made in base of plasma generator head in the form of truncated cone whose large base is on discharge chamber side. Discharge chamber is joined with at least two receiver chambers the last one being mounted in plasma generator base and communicating with discharge chamber inlet through gas-distribution unit. Receiver chambers are serially interconnected by means of at least three channels uniformly distributed over perimeter. Cylindrical case of discharge chamber is joined at outlet with cooled baffle plate in the form of semi-bell; outlet pipe of feeder nozzle is made in half-bell case and beveled towards plasma generator to differentiate material feed along said bevel. EFFECT: enhanced stability of working gas pressure and flowrate; increased capacity; reduced power requirement at high-quality spheroidization. 5 cl, 2 dwg, 3 tbl