Concrete pump wear plate and cutting ring are a pair of closely fit parts with relative movement. The contact surface of them is brazed with a layer of wear-resistant material. Through the special-shaped nut at the tail end of the spline shaft of the S valve, the gap between the plate & ring can be adjusted within 0.1 ~0.2mm. The rubber spring assembled between the S-shaped tube and the wear ring enables the relative movement of the cutting ring and the spectacle plate to be flexible and free.