Compression type expansion valve

The valve seat of the pressure type expansion valve includes an annular valve seat body, and the sealing surface of the valve seat is set on a plane close to the valve body. Thermal spraying utilizes the contact between the outer surface of the valve seat sealing protrusion and the sealing surface of the valve body to provide a new type of metal seal between the valve seat and the valve body. Under the same working conditions, due to the decrease in contact area, the sealing pressure increases, avoiding leakage.