Cryogenic Tank Car Manway Relief for Inner Tank Access
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Solution Overview
Problem
Conventional cryogenic tank cars face challenges in accessing the inner tank for servicing due to the small size of traditional vacuum release nozzles, which limits access and requires cutting through the outer tank, and are insufficient in venting excess pressure in the annular space between the inner and outer tanks.
Innovation Solution
A larger manway relief nozzle and plate system, where the manway relief plate is held in place by differential pressure created by a vacuum between the inner and outer tanks, allowing for direct access to the inner tank without cutting through the outer tank and enabling greater pressure venting capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional vacuum release nozzles are used, then the tank car maintains structural integrity, but access to the inner tank is limited and requires cutting through the outer tank
Solution Approach 1:
The invention combines the vacuum release nozzle function with the manway access function into a single integrated structure. The enlarged nozzle serves dual purposes: maintaining vacuum integrity while providing sufficient access to the inner tank, eliminating the need for separate access openings and cutting operations.
Solution Approach 2:
The nozzle is enlarged in dimensional scope from traditional small-diameter designs to a larger diameter that accommodates both vacuum release and personnel/tool access. This dimensional expansion transforms the nozzle from a purely functional vacuum component to a multi-functional access portal.
2Object-generated harmful factors
If traditional vacuum release nozzles are used, then the outer tank structure remains intact, but pressure venting capacity is insufficient
Solution Approach 1:
The invention merges the vacuum release function with pressure venting capability into a single enlarged nozzle structure. This unified design allows the nozzle to handle both functions simultaneously, preventing pressure buildup while maintaining structural integrity without requiring multiple separate components.
3Ease of operation
If the nozzle is enlarged to provide access, then access to the inner tank improves, but the sealing requirement becomes more challenging
Solution Approach 1:
The invention introduces a gasket as an intermediary sealing element between the enlarged nozzle and the manway plate. This gasket mediator accommodates the larger dimensions while maintaining vacuum integrity, solving the sealing challenge posed by the enlarged access opening.
4Object-generated harmful factors
If a larger manway relief system is used, then pressure venting capacity increases, but the clamping force requirement increases
Solution Approach 1:
The vacuum pressure differential across the manway plate creates a self-generating clamping force that secures the gasket and maintains the seal. The system uses its own operating vacuum to provide the necessary clamping force, eliminating the need for additional mechanical fastening mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The larger manway relief system provides better sealing and increased clamping force, allowing for safer and more efficient access to the inner tank while effectively preventing pressure buildup in the annular space, thus preventing inner tank collapse.
Implementation Method 1
A space defined by an interior surface of the outer tank and an exterior surface of the inner tank is configured to hold a vacuum
Implementation Method 2
In response to applying the vacuum to the space, a differential pressure between the space defined by the interior surface of the outer tank and the exterior surface of the inner tank and a space external to the outer tank secures the outer manway plate to the outer nozzle
Implementation Method 3
A vacuum is applied to the annular space between the two tanks to provide insulation to the commodity transported within the inner tank
Data Source
AI summary
A cryogenic tank car tank includes an outer tank, an inner tank positioned within the outer tank, an inner nozzle, and inner manway plate, an outer nozzle, and an outer manway plate. The inner nozzle defines an opening in the inner tank. The inner manway plate is welded to the inner nozzle and covers the opening in the inner tank. The outer nozzle defines an opening in the outer tank and is positioned above the inner nozzle, such that the inner manway plate is accessible through the outer nozzle. The outer manway plate couples to an upper edge of the outer nozzle to cover the opening in the outer tank. In response to applying the vacuum to the annular space between the inner and outer tanks, a differential pressure between the annular space and a space external to the outer tank secures the outer manway plate to the outer nozzle.