Isolation plug with energized seal

A plugging head [20] adapted for use in pipeline isolation, the plugging head comprising:

• a seal [30] sized to engage a pipe wall and having an unset position and a set position;
• a plurality of metal support segments [40] located on a side of the seal and moveable between the unset and set positions in a transverse direction radially outward and inward;
• each metal support segment of the plurality including a seal-facing surface [41] including at least two inclined thrust surfaces [43A, 43B, 43C] and a concave-portion [45] containing one of the at least two inclined thrust surfaces, a portion [35] of the side of the seal residing within the concave portion when in the unset and set positions;
• wherein in the unset position a portion [33] of the seal is covered by adjacent metal support segments of the plurality;
• and
• wherein in the set position the portion of the seal is exposed between the adjacent metal support segments.