The combination of a pair of pipes (102, 104) each having a peripheral groove (110, 112) near its end and a coupling (204, 206) for coupling together the ends of the pipes in a fluid tight manner, the coupling comprising the combination of a plurality of coupling parts each having an arcuate inside surface of the same radius as the outside surfaces of the pipes, a plurality of projections (234) on the inside surface, which projections engage respectively in the peripheral grooves, and a radial groove (232) between the projections (234) clamping means for clamping the coupling parts together to clamp, onto the ends of the pipes, a locating ring (236) partially received within the locating groove and projecting therefrom into the path of the pipes, and sealing means (108), preferably in the form of a pressure assisted seal, carried by the locating ring providing a seal between the ends of the pipes.