Patent ID: 7699207

Claim:
Compression belting for backing an endless course of a butt-weld seam between pipe or tank sections from inside a hollow core as a welding backup provision during welding on the outside thereof, comprising: one or more belt sub-assemblies of which at least one is a major belt sub-assembly for backing a majority of the seam's course, said major belt-subassembly comprising: a plurality of tiles, each having a seam-covering surface spaced by four edges from a utility surface, the four edges comprising a pair of anterior edges spaced by a pair of lateral edges, wherein the tiles are arranged in a procession between one end tile and another end tile with anterior edges between adjacent tiles situated in close or abutting positions, and an inter-tile linking system linking all the tiles flexibly so that the major belt sub-assembly is capable of backing at least a majority of the seam's course from inside the hollow core as with the utility surfaces facing the hollow core and the seam-backing surfaces lapping across the seam over onto margins of inside walls of the pipe or tank sections; and an expansion-force application system inserted between the one and another end tiles for applying an expansion force on said end tiles and thereby squeezing out the slack between adjacent tiles to achieve self-holding capability as well as promoting close proximity or contact between the tiles' seam-covering surfaces and the overlapped margins of the inside walls of the pipe or tank sections.