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