Abstract: A pipe union for joining two pipe ends in an end-to-end relationship. On each pipe end a flange, at least one clamping element, and one chamber element are fitted , which can be braced against one another and which among them enclose a shaped seal, each of whose two axial ends protrudes into a respective adapted recess of the chamber elements covering the seal. The seal is an outer elastomer ring supported on the jacket faces of the two pipe ends and has a central annular groove open to the inside. An inner ring that overlaps the butt joint is loosely pressed into this central annular groove. The clamping elements are supported with a radially inwardly located clamping rim on the associated pipe end, and with a radially outwardly located clamping rim on a clamping face disposed concentrically with respect to the pipe ends.