a coupling assembly is provided for releasably interconnecting confronting ends of conduit members . the coupling assembly creates a self - locking , and self - bonding connection wherein locking and unlocking is achieved by a predetermined amount of rotation of a lock nut group with respect to a stationary threaded flange . the overall construction of the coupling assembly creates the rigid connection between the conduit members , yet adequate sealing between the conduit members is provided by a single sealing member .