Cryogenic Storage Suspension With Movement Limiter
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Solution Overview
Problem
Conductive heat transfer from the external reservoir to the internal reservoir in cryogenic fluid storage units is significant, primarily through the suspension, which can lead to irreversible deformation and damage during exceptional stresses, compromising the integrity and efficiency of the storage unit.
Innovation Solution
Incorporating a movement limiter in the suspension system that limits deflection of the inner tube relative to the internal reservoir, allowing for a reduced wall thickness to minimize heat transfer by conduction, while preventing irreversible deformation during exceptional stresses, and using coaxial tubes with thermal insulation to reduce heat transfer by radiation and conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the wall thickness of the inner tube is reduced to minimize heat transfer by conduction, then heat transfer by conduction is reduced, but the mechanical strength and resistance to exceptional stresses deteriorate
Solution Approach 1:
The movement limiter acts as an intermediary protective element that engages with the inner tube during exceptional stresses. It provides mechanical support and limits deflection without being part of the normal load-bearing structure, allowing the inner tube to maintain reduced wall thickness for thermal insulation while gaining protection against stress-induced deformation
Solution Approach 2:
The movement limiter is pre-positioned within the orifice to provide beforehand protection against exceptional stresses. When abnormal forces occur (such as vehicle impacts), the movement limiter engages first to limit deflection and prevent the inner tube from entering the plastic deformation range, cushioning the tube against damage before stress can cause irreversible deformation
2Strength
If the wall thickness of the inner tube is increased to withstand exceptional stresses, then mechanical strength is improved, but heat transfer by conduction increases
Solution Approach 1:
The suspension system is segmented into distinct functional components: the inner tube for normal mechanical support and thermal isolation, and the movement limiter for exceptional stress protection. This segmentation allows each component to be optimized for its specific function - the inner tube can have minimal wall thickness for thermal performance while the movement limiter handles stress protection
3Reliability
If a movement limiter is added to prevent irreversible deformation during exceptional stresses, then reliability is improved, but device complexity increases
Solution Approach 1:
The movement limiter serves multiple functions within a single component: it limits deflection during exceptional stresses, prevents the inner tube from entering the plastic range, and engages with existing structures (the orifice and rigid member) already present in the suspension system. This multi-functionality justifies the added complexity by providing comprehensive protection without requiring multiple separate components
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 solution effectively reduces heat transfer by conduction and radiation, maintaining the structural integrity of the storage unit under normal and exceptional mechanical stresses, thereby enhancing the storage efficiency and longevity of cryogenic fluids.
Implementation Method 1
limiting deflection of the inner tube relative to the internal reservoir in a plane perpendicular to a central axis of the inner tube... prevents it from entering the plastic range and thus undergoing irreversible deformation
Implementation Method 2
Conductive heat transfer from the external reservoir to the internal reservoir takes place mainly via the suspension... The inner tube is designed only to withstand the usual mechanical stresses associated with normal storage use
Implementation Method 3
To limit convective heat transfer from the external reservoir to the internal reservoir, the space between the internal and external reservoirs is typically kept under a high vacuum
Implementation Method 4
Radiation transfer is limited by placing a layer of insulating material on the internal reservoir
Data Source
AI summary
A storage unit comprises an internal reservoir inwardly delimiting a cryogenic fluid storage volume, an external reservoir housing the internal reservoir and a suspension attaching the internal reservoir to the external reservoir. The suspension has a connection which comprises an outer tube, a bottom plate, an inner tube arranged inside the outer tube, and a movement limiter. The outer tube has an outer proximal end attached to the internal reservoir and an outer distal end located inside the storage volume The bottom plate closes the outer distal end. The inner tube has an inner proximal end connected to the external reservoir and an inner distal end attached to the internal reservoir. The movement limiter limits deflection of the inner tube relative to the internal reservoir in a plane perpendicular to a central axis of the inner tube.