Abstract: A refurbishment process for a volumetric screw compressor of the ‘oil-free’ type, which comprises a male rotor and a female rotor, is described. The process comprises visually checking the wear condition of the rotors, treating their surface for removing the previous coating, and applying a new coating on the surface. The composition of the coating applied on the surface of the rotors consists of the following materials: Material Amount (g) Polytetrafluoroethylene 750 ÷ 850 (954G 303 C Teflon, DuPont) Amorphous graphite powder 300 ÷ 400 Thinner for spray cleaning apparatuses 200 ÷ 270 (8595 thinner, DuPont) Methyl ethyl ketone (MEK) 170 ÷ 220 Cellosolve acetate coating additive 200 ÷ 300 (Syn Fac 800 resin).

Abstract: A refurbishment process for a volumetric screw compressor of the ‘oil-free’ type, which comprises a male rotor and a female rotor, is described. The process comprises visually checking the wear condition of the rotors, treating their surface for removing the previous coating, and applying a new coating on the surface.