Abstract: To couple two pipes for hot fluids together, a sealing membrane of temperature and corrosion-resistant material is located transversely within a ring-shaped chamber or space surrounding the end portions of the pipes, the sealing membrane being welded to the adjacent wall portions defining the ring chamber, and the at least one and preferably two sealing and support cushions or pillows being placed adjacent the sealing membrane, to permit limited angular and axial movement of the pipe ends with respect to each other while, effectively, preventing substantial torsional excursion. The membrane may be corrugated or stepped, located transversely to the pipes or at an inclination with respect thereto. Two membranes may be used, inclined towards each other (FIG. 3) and multi-pipe units can be coupled by a single membrane (FIGS. 8, 9).