Patent ID: 8322556

Claim:
A method of forming a closure for a vessel, comprising: providing a hub having an access opening to the vessel, the hub having a circumferential stop face spaced between the access opening and the vessel and one or more recesses each extending radially outward from an adjacent inner surface of the hub; positioning a door between the stop face and the vessel, such that fluid pressure in the vessel forces the door against the stop face; providing an annular seal for sealing between the door and the stop face; forming one or more of lugs each extending radially outward from an adjacent exterior surface of the door, such that during opening of the closure a respective lug passes through a respective recess in the hub and a portion of the annular seal extends radially outward of the door and circumferentially along a respective lug to seal the lug to the hub; moving the door into sealing engagement with the stop face; and pivoting the door to pass the door and the one or more lugs through the one or more recesses and out of the hub.