Cryostatic device with a neck pipe with a load-bearing structure and an outer tube surrounding the load bearing structure for reducing cryogenic consumption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cryostat systems face significant heat load issues due to neck tubes, which are necessary for mechanical support and fluid flow but lack separate optimization for thermal conductivity and mechanical strength, leading to inefficient helium consumption and increased operating costs.
Innovation Solution
The neck tube is designed with separate sections for mechanical fastening and diffusion barrier functions, using plastic for support and metal extensions for connection, optimizing materials for reduced thermal conductivity and enhanced mechanical strength, and incorporating a diffusion barrier made of a material that minimizes cryogen leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If neck tubes are made with thin walls to reduce heat conduction, then thermal insulation is improved, but mechanical strength and load-bearing capacity deteriorate
Solution Approach 1:
The neck tube is divided into two separate functional components: an inner tube that provides mechanical support and load-bearing capacity, and an outer tube that serves as a diffusion barrier. This segmentation allows each component to be optimized independently for its specific function, resolving the contradiction between thin-wall thermal insulation and mechanical strength requirements.
Solution Approach 2:
The invention uses composite construction with the inner tube made of material optimized for mechanical strength (such as stainless steel or aluminum alloy) and the outer tube made of material optimized for preventing cryogen diffusion (such as stainless steel with specific wall thickness). This composite approach allows simultaneous optimization of both mechanical properties and thermal properties.
2Loss of energy
If neck tubes are made with thin walls to reduce heat conduction, then thermal insulation is improved, but the ability to support the weight of the cryogen tank deteriorates
Solution Approach 1:
The load-bearing function is separated from the diffusion barrier function. The inner tube is specifically designed to support the weight of the cryogen tank and all components within the vacuum container, while the outer tube provides the diffusion barrier. This functional separation resolves the contradiction between minimizing heat conduction and maintaining load-bearing capacity.
Solution Approach 2:
The inner tube acts as an intermediary structural element that carries the mechanical load from the cryogen tank to the support structure, while the outer tube provides the hermetic seal. This intermediary approach allows each component to be optimized for its primary function without compromise.
3Device complexity
If a single material is used for both mechanical support and diffusion barrier functions, then device complexity is reduced, but separate optimization of thermal and fluidic properties becomes impossible
Solution Approach 1:
The neck tube assembly is segmented into inner and outer tubes with distinct functions. The inner tube optimizes mechanical support properties, while the outer tube optimizes diffusion barrier properties. This segmentation enables separate optimization of thermal and fluidic properties without significantly increasing overall device complexity, as the two tubes work together as an integrated system.
Solution Approach 2:
Different parts of the neck tube assembly have different material properties and thicknesses optimized for their specific functions. The inner tube has properties optimized for mechanical strength, while the outer tube has properties optimized for preventing cryogen diffusion. This local quality approach allows simultaneous optimization of multiple performance criteria.
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
This design significantly reduces heat load on the cryogen tank, allowing for more efficient cooling, longer helium refill intervals, and reduced operating costs, while maintaining system reliability and accessibility.
Implementation Method 1
the outer tube is made of a material through which cryogenic fluid cannot diffuse, or only in a practically non-measurable amount
Implementation Method 2
The supporting structure is made of plastic and at both ends has a metal extension for connection to the vacuum or the cryogen container, wherein the supporting structure supports the weight of the cryogenic container and is made of a material in which for the ratio σ/θ of maximum permissible mechanical stress σ to the integral θ of the thermal conductivity λ
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5b
AI summary
A cryostat arrangement (1) with a vacuum container (2) and a cryogen container (3) arranged therein, the vacuum container having a neck tube (4) leading to the cryogen container (3) and having a supporting structure (4a) and a neck tube surrounding the supporting structure (4a). Outer tube (4b), wherein a connection can be made from the cryogenic container to an area outside the vacuum container via the neck tube, so that cryogenic fluid can flow from the cryogenic container to an area outside the vacuum container or vice versa, is characterized in that the to a mechanical The parts of the neck tube used to hang the cryogenic container on the vacuum container on the one hand and the parts of the neck tube used to set up a diffusion barrier between the interior of the cryogenic container and the interior of the vacuum container on the other hand are spatially separated from one another and are made of differently optimized materials so that the supporting structure structure supports the weight of the cryogenic container and is made of a material in which the ratio σ/θ of the maximum allowable mechanical stress σ, with σ > 100MPa, to the integral θ of the thermal conductivity λ over the temperature range ΔT between 300K and 4K, with θ < 300W/m, the following applies: σ/θ > 1/3(MPa m)/W, and that the outer tube is made of a material through which cryogenic fluid cannot diffuse or can only diffuse in a practically immeasurable amount, and which can be connected in a fluid-tight manner to other components of the cryostat arrangement, so that the resulting integral leakage rate from the cryogenic container into the vacuum container is less than 10-6 mbar·l/s. In this way, the heat input into the cryogenic container originating from the neck tubes can be significantly reduced.