Pipeline coupling (6) for connecting individual pipeline sections (51, 52), and pipeline system, wherein individual pipeline sections (51, 52) are clamped together at their end faces by pipe-clamp-like split couplings, and a sealing ring (10) is arranged inside the split coupling part (8), said sealing ring (10) having at least one pressure chamber (12) and at least two spaced-apart sealing surfaces (1 1) which, under the delivery pressure of the medium to be delivered, bear in a sealing manner against the outer circumference of the respective pipeline sections (51, 52), and wherein the sealing ring (10) furthermore has an encircling distance web (13) which points radially inwards and extends between the end faces of the clamped pipeline sections (51, 52),; wherein at least one connectingpassage which is permanently effective under delivery pressure is provided in the pipeline coupling (6) between the interior of the pipeline system and the pressure chamber (12) in the sealing ring (10), preferably by apertures (15) in the distance web (13).