Monomer axial flow type back valve with sealing ring arranged at front

The utility model discloses a single-body axial-flow type check valve with a front packing ring, which comprises a valve housing, a valve body, a valve flap component, a valve shaft, a packing ring, a retainer ring, a front fulcrum bearing as well as a rear fulcrum bearing, a spring, etc. The valve housing and the valve body are integrated as a whole; the packing ring is arranged at an upper port of the valve body; a convex type retainer ring is arranged in front of the packing ring; a fixed pin is arranged between the packing ring and the convex type retainer ring; zero leakage between the packing ring and the valve body can be realized by utilizing an O-shaped ring, thereby leading the single-body axial-flow check valve with large caliber and overlarge caliber to be realized on the processing technique, simplifying the technique, increasing the precision, and optimizing the performance; by adopting the single-body structure, the leakage point toward the atmosphere does not exist.