Abstract: A coupling for connecting liquid conduits is disclosed, said coupling comprising an insert nipple (1) and a receiving nipple (15), said nipples being axially moveable in relation to each other for connection and disconnection. The insert nipple (1) comprises a stationary sleeve (2) with a sealing valve body (3) spring-biased and inwardly axially movable therein. The receiving nipple (15) has an outer sleeve (16), an inner spring-biased and inwardly axially movable sealing sleeve (17) and a stationary valve central stay (28) which in disconnected condition sealingly cooperates with the sealing sleeve (17). According to the invention the sealing sleeve (17) is provided at its outer end portion with an inner wedge seal (21) arranged to sealingly cooperate with a wedge-forming conical outer surface (4) on the front end portion of the outer sleeve (2) and comprising a conical support ring (21b).