{HEAD ~ This trough} is then deepened by extending {TAIL ~ its inner wall} in upward direction, and the thus formed deeper trough is then filled with welding material, preferably up to the top surface of the pressure conveying element 
{ HEAD ~ This trough } is then deepened by extending { TAIL ~ its inner wall } in upward direction , and the thus formed deeper trough is then filled with welding material , preferably up to the top surface of the pressure conveying element
HEAD HEAD HEAD HEAD HEAD HEAD REL OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH