Synchronized Davit Closure Assembly for Inclined Pressure Vessels
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Solution Overview
Problem
Existing quick opening closures for pressure vessels or pipelines, when mounted in an inclined position, face issues with supporting and aligning the closure door due to unbalanced weight distribution and thread misalignment, leading to wear and difficulty in sealing, especially when the door is rotated and unthreaded from the hub.
Innovation Solution
A davit assembly with a davit nut synchronized with a threaded door pin, which threads into or out of a davit nut in synchronization with the closure door, providing support and maintaining alignment to prevent wear and ensure proper sealing, comprising a standoff, hinge, radial pin, and locking mechanisms for horizontal and vertical adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the closure door is rotated and unthreaded from the hub in an inclined position, then rapid access to the vessel or pipeline is achieved, but the unbalanced weight distribution causes the hinge arms to twist out of plane and the threaded connection to become misaligned
Solution Approach 1:
A davit assembly acts as an intermediary support mechanism between the closure door and the hub. The davit includes a davit arm that supports the closure door during opening and closing operations, and a davit nut that receives the door pin to maintain proper alignment. This intermediary structure prevents the hinge arms from twisting and keeps the threaded connection aligned throughout the motion sequence.
Solution Approach 2:
The davit assembly is pre-configured with the davit arm positioned to support the closure door before opening begins. The davit nut is pre-threaded onto the door pin at a specific offset distance, establishing the correct timing relationship between door rotation and pin withdrawal before the actual opening operation commences. This preliminary setup ensures proper synchronization during operation.
2Reliability
If the closure door is supported during opening, then thread wear is prevented, but the mechanism becomes more complex with additional components
Solution Approach 1:
The davit assembly serves multiple functions: it supports the closure door during opening, maintains alignment of the threaded connection, provides a pivot point for the door pin, and ensures proper timing between door rotation and pin withdrawal. By consolidating these functions into a single integrated assembly, the design achieves reliability without excessive complexity.
Solution Approach 2:
The davit arm and davit nut are combined into a single davit assembly that works together to support and align the closure door. The davit arm provides structural support while the davit nut maintains threaded alignment, and both components are integrated to function as a unified support mechanism throughout the opening sequence.
3Manufacturing precision
If the door pin threads into the davit nut at the correct timing, then alignment is maintained, but the mechanism requires precise coordination between multiple threading operations
Solution Approach 1:
The davit nut is pre-threaded onto the door pin at a specific offset distance from the pin head before the opening operation begins. This preliminary positioning establishes the correct timing relationship, so that as the door rotates and the pin withdraws, it automatically threads into the davit nut at the precise moment needed to maintain alignment, without requiring active control or complex coordination mechanisms.
Data Source
AI summary
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.