Cryogenic Pipe-in-Pipe Bulkhead for Thermal Stress Transfer
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Solution Overview
Problem
Cryogenic pipelines face significant thermal stress due to the low temperature of transported fluids or gases, which existing insulating materials fail to alleviate effectively, leading to structural instability and costly solutions like expensive alloys or complex installation processes.
Innovation Solution
The use of bulkheads that transfer thermal stress from the inner cryogenic pipe to an outer pipe, combined with insulating materials and spacers, creates a structurally stable pipeline configuration that maintains mechanical simplicity and reduces thermal stress without the need for expensive alloys or complex installations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If insulating materials are used in the annular space, then thermal loss is reduced, but thermal stress is not alleviated and structural support is insufficient
Solution Approach 1:
The patent introduces an intermediary mechanism (bulkhead with stress transfer features) between the inner and outer pipes that mediates the thermal stress. This bulkhead transfers axial thermal stress from the inner pipe to the outer pipe, allowing the insulating material to reduce thermal loss while the stress transfer mechanism addresses the structural support deficiency.
2Stress or pressure
If expansion joints and bellows are used to reduce thermal stress, then thermal stress is significantly reduced, but leakage risk increases and installation becomes more difficult
Solution Approach 1:
The patent extracts the stress relief function from complex expansion joints and bellows, isolating only the essential stress transfer capability. By using a simplified bulkhead design with integrated stress transfer features, the patent removes the problematic leakage-prone components while retaining the beneficial thermal stress reduction.
3Stress or pressure
If stress cones are used to transfer thermal stress to the outer pipe, then thermal stress control is improved, but installation complexity increases due to numerous welds
Solution Approach 1:
The patent merges the stress transfer function with the bulkhead structure itself, eliminating the need for separate stress cones and multiple welds. The bulkhead is designed with integrated features that directly transfer thermal stress from the inner pipe to the outer pipe, combining multiple functions into a single component that is easier to manufacture and install.
4Stress or pressure
If INVARTM steel is used for the pipeline, then thermal stress is almost completely avoided, but construction cost becomes prohibitively expensive
Solution Approach 1:
The patent uses conventional, cost-effective pipe materials instead of expensive INVARTM steel, accepting that some thermal stress will occur. The stress transfer bulkhead then manages this stress by transferring it to the outer pipe, achieving thermal stress control without the prohibitively high material costs of INVARTM steel pipelines.
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 configuration provides increased mechanical stability and thermal insulation while being cost-effective and easier to install, addressing the thermal stress issues in cryogenic pipelines without resorting to expensive materials or complex installations.
Implementation Method 1
an annular space that is filled with an insulating material
Implementation Method 2
a bulkhead that transfers thermal stress from an inner pipe to an outer pipe
Data Source
AI summary
A pipe-in-pipe pipeline has a bulkhead that transfers thermal stress from an inner pipe to an outer pipe, wherein at least part of the bulkhead forms a conduit for a product traveling through the inner pipe.