Abstract: An improved closure assembly for a pressure vessel or pipeline is described, where the closure assembly includes a davit assembly pivotally connecting a closure door to a closure hub where the closure door threadably attaches to the closure hub. The closure door is also threadably attached to the davit assembly where the threaded attachment between with the davit assembly is synchronized or timed with the threaded attachment between the closure door and the closure hub.

Abstract: A closure is provided for a pressure vessel or pipelines that can provide quick and easy access to the interior of a pressure vessel or pipeline and means for a pressure tight seal between the hub and door. The closure can incorporate means for mechanically fastening the door to the hub using an external split clamp ring actuated by a toggle mechanism. A locking mechanism can be provided to safeguard against unintended closure actuation and provides a layer of redundancy to the holding characteristics of the toggle mechanism. The locking mechanism can be interlocked to a pressure alert system to ensure any differential pressure condition contained within the closure is detected prior to disengaging the locking mechanism and actuating the toggle mechanism.

Abstract: A closure is provided for a pressure vessel or pipelines that can provide quick and easy access to the interior of a pressure vessel or pipeline, and means for a pressure tight seal between the hub and door. The closure can incorporate means for mechanically fastening the door to the hub using an external split clamp ring actuated by a toggle mechanism. A locking mechanism can be provided to safeguard against unintended closure actuation, and provides a layer of redundancy to the holding characteristics of the toggle mechanism. The locking mechanism can be interlocked to a pressure alert system to ensure any differential pressure condition contained within the closure is detected prior to disengaging the locking mechanism and actuating the toggle mechanism.