PRESSURE TIGHT PLUG

A pressure tight plug for sealing a coupler of a dry disconnect valve includes a housing, a main flow valve, and at least one urging member being rotatable with respect to the housing of the coupler. The pressure tight plug includes a body, a locking ring, a pressure relief lock valve, and a pressure relief channel. The body includes an internal region for sealing adjacent the main flow valve of the coupler member, and a flanged perimeter for securing the plug to the coupler. The locking ring is receivable on, and rotatable with respect to, the body for engaging with the at least one urging member of the coupler. The pressure relief lock valve is fixed with respect to the body. The pressure relief channel extends from the internal region of the body to atmosphere, via said pressure relief lock valve. The pressure relief lock valve is arranged such that in a valve closed position the pressure relief lock valve is engaged with the locking ring, therein restricting movement of the locking ring and therein fixing the plug to the coupler.