Northey's hook & claw compressor has contra-rotating rotors, which do not touch so there is no wear between the components and no need for lubrication. No oil means no contamination of the process gas. It is truly oil-free in operation. Rotors and bodies are machined to very close tolerances from solid billet or castings. Every casting is pressure tested to a minimum of 5 barg and every completed compressor or vacuum pump undergoes extensive performance and reliability testing before leaving the works. ATEX version available for the oil & gas industry.