The object of the invention is a mechanical connector assembly for joining pipes conveying fluids such as hydrocarbons. The connector joins two internally threaded pins (7a) and (7b) attached to pipe sections (3) to an externally threaded box (1). Alternatively, a single pin (7) anchored to a pipe section may be anchored to a box (8) joined to the opposite pipe section (3). Redundant mechanical liquid seals provide a wedge seal (12) as well as a thrust seal (6) where an extension of the pin (7a) abuts against the other pin (7b) or where it bears against the box (8). The connection is made by applying external pre-stress to the pin, allowing the box (1) to be rotated with limited resistance before releasing the external pre-stress, resulting in a high level of pre-stress sufficient that the thrust shoulders (5) of the pin (1) will not separate before the applied load approaches the yield strength of the connector material. This provides a double liquid seal consisting of a thrust shoulder (6) in addition to a
