The brine filtering device includes a pre-filtering unit having first and second pre-filtration drums arranged to rotate coaxially about a horizontal axis and a safety filtering unit having a safety filter sleeve submerged in a tank and connected to an outlet. The first and second pre-filtration drums have their lower regions submerged in brine contained in a tub. An inlet hopper receives brine to be filtered and forces it into the first pre-filtration drum through an upper region of its filtering wall. Brine exits a lower region of the first pre-filtration drum and is collected in the tub. Brine enters into the second pre-filtration drum through a lower region of its filtering wall. Brine is poured into tank through an open side wall of the second pre-filtration drum.