GAS-DYNAMIC SCRAPER Russian patent published in 2002 - IPC

FIELD: construction equipment; cleaning surfaces of pipes and metalwork from old and defective anticorrosive coats, such as bitumen, resins, film and the like which are difficult to clean by standard methods. SUBSTANCE: double-stage nozzle unit of fire-jet tool is just contraction with critical section whose elongation is diffuser terminating in slotted hole; secured on one side is scraper with cutting edge which is blown by supersonic flow of gas at high temperature for local melting of coat to be removed. EFFECT: prompt and enhanced cleaning or complete removal of insulation. 3 dwg