Lower tube socket with foreign matter filtering function

A lower tube socket with a foreign matter filtering function, comprising a plurality of blades (8) the axes of which are in parallel with each other, and a plurality of rib assemblies (9) the axes of which are in parallel with each other, wherein the axes of the rib assemblies and the axes of the blades are mutually perpendicular; each rib assembly is composed of two symmetrical ribs, clamping grooves, the number of which corresponds to that of the blades, are arranged on the opposite surface of the two ribs respectively, and the blades are clamped in the clamping grooves; and each blade comprises several convex pieces, the convex directions of which are consistent, every two adjacent convex pieces are connected via a straight section, grooves are arranged on an upper end surface and a lower end surface of the straight section respectively, the opening direction of the grooves and the convex direction of each convex piece are mutually perpendicular, and the rib assemblies are clamped in the grooves. The lower tube socket has an excellent performance in the three respects, i.e. structural strength, filtering capability and pressure drop of coolant, respectively.