Abstract: A dirt scrapper assembly providing an annular stiffening structure adapted to connect with a tube for sealing the tube is disclosed. The annular stiffening structure includes a plurality of first axial sections equally spaced and extended along axial direction on an outer side of the tube. Curvature of corresponding radii is provided on the outer surface of the first axial sections. The annular stiffening structure further includes a second axial section extended along axial direction of the tube on inner side of the tube. The plurality of first axial sections and the second axial section are connected by a connection section of the stiffening structure configured to contact with an end surface of the tube. The connection section having a cut section at the bottom surface extended over the length of each of the plurality of first axial sections to provide flex to the plurality of first axial sections.