FIELD: mechanical engineering and metallurgy. SUBSTANCE: apparatus has full-scale lines for purifying of cutting liquids from solid particles, free oil and foreign matter, including at least one centralized purifying system. Apparatus is further equipped with floater having oil scraping drum, magnetic separator, reserve three-phase "oil-liquid-solid sediment" centrifugal separator, with said floater, magnetic and centrifugal separators being arranged in random succession. Oil scraping drum has adjustable rotational speed and is arranged in bypass pattern with respect to centrifugal separator and floater. Apparatus is equipped with additional purifiers having capacity within the range of 1-10% of capacity of full-scale purifying lines. Additional purifiers may be periodically connected to each centralized purifying system through pumps, inlet and outlet pipelines connected in any two spaced points of full-scale cutting liquid circulation circuit in centralized purifying system. EFFECT: increased cutting liquid purifying extent and fineness, increased service life of cutting liquid, reduced costs per unit of consumption of cutting liquid. 2 cl, 2 dwg
