Internal Line-Up Clamps for Welding Pipes

Abstract

An internal line-up clamp for welding pipe lengths end-to-end includes a clamp ring made up of a plurality of clamp ring elements that are angularly distributed around the circumference of the clamp ring. The clamp ring elements are divided into mutually opposed groups that are interdigitated such that the clamp ring elements alternate from one group to the other around the circumference of the clamp ring. A longitudinally-acting actuator system drives relative longitudinal movement of the groups to effect clamping expansion of the clamp ring by wedging interaction between the circumferentially-alternating clamp ring elements of the groups. By expanding the clamp ring in alignment with a weld plane between the abutting ends, the same clamp ring may be used to align the pipe lengths and to back a weld between them.

1 - 31 . (canceled) 
     
     
         32 . An internal line-up clamp for welding pipe lengths end-to-end, the clamp comprising a support structure, the support structure supporting both a clamp system and a brake system, wherein the brake system comprises at least one brake unit that is mounted to the support structure by a pivot permitting limited angular movement between the brake unit and the support structure. 
     
     
         33 . The clamp of  claim 32 , wherein the pivot comprises a bush between the support structure and the brake unit. 
     
     
         34 . The clamp of  claim 32 , wherein the pivot comprises a swivel or a hinge between the support structure and the brake unit. 
     
     
         35 . The clamp of  claims 32 , wherein the brake unit comprises two or more jacks acting radially outwardly in mutual opposition. 
     
     
         36 . The clamp of  claim 32 , wherein the support structure is elongate, the clamp system is mounted to the support structure at a central region of the support structure and the brake unit is mounted to the support structure at, or adjacent to, an end of the support structure remote from the clamp system.