Insulated Pipe-in-Pipe Weld Joint for Low Thermal Loss
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Solution Overview
Problem
Conventional methods for joining insulated pipe-in-pipe systems suffer from significant thermal loss and mechanical failure due to conductive heat transfer paths and complex configurations, particularly in systems subjected to bending and straightening forces.
Innovation Solution
A ring is welded to the outer surface of the inner pipe, and the outer pipe is recessed to terminate at the ring, with a sleeve segment coupled to the rings after welding the inner pipes together, enhancing mechanical strength and minimizing thermal conductivity by applying joint insulation material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If end caps are used to enclose the annular insulated space, then the insulated space is sealed, but a conductive heat transfer path is formed leading to significant thermal loss
Solution Approach 1:
The end cap is removed from the system and replaced with a bulkhead structure that integrates the sealing function while eliminating the conductive heat transfer path. The bulkhead is welded directly to the inner and outer pipes, creating a thermal break that maintains insulation integrity while providing mechanical support for the insulation material.
2Loss of energy
If a bulkhead is employed to reduce thermal loss, then heat transfer paths are reduced, but the configuration becomes complex requiring numerous welds and assembly steps
Solution Approach 1:
The bulkhead structure merges multiple functions into a single integrated component: it provides thermal breaking, mechanical support for insulation, structural reinforcement, and a mounting interface for the insulation material. This consolidation reduces the number of separate parts and assembly steps while maintaining thermal performance.
3Ease of manufacture
If conventional pipe connections are used, then joining is simple, but the system is prone to mechanical failure under bending and straightening forces
Solution Approach 1:
The bulkhead creates a composite structure where the inner pipe, bulkhead, and outer pipe work together as an integrated load-bearing assembly. The insulation material bonded to the bulkhead provides additional structural reinforcement, creating a composite system that resists bending and straightening forces while maintaining connection simplicity.
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 method reduces thermal loss and mechanical failure by allowing load sharing between inner and outer pipes, supporting bending and straightening operations, and maintaining structural integrity while reducing weight and heat transfer.
Implementation Method 1
respective ends of the inner pipes are welded together
Implementation Method 2
enhancing mechanical strength of the joint
Implementation Method 3
applying joint insulation material to the weld joint, thereby enhancing mechanical strength of the joint while minimizing thermal conductivity
Implementation Method 4
the outer pipe is recessed from the inner pipe and terminates at the ring
Data Source
Figure 1~2
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Figure 5~6
AI summary
An insulated joint in a pipe-in-pipe system comprises a weld that connects two inner pipes while respective outer pipes circumferentially enclose the inner pipes and terminate at a position distal from the weld. Respective rings are coupled to the inner pipes at the distal position and the outer pipes are welded to the rings. A joint insulation material covers the weld, and a sleeve segment covers the weld and joint insulation material. Preferably, the sleeve segment is formed from two half-pipe sleeve portions and welded to the rings to so secure the sleeve segment to the joined pipe-in-pipe segments. Contemplated pipe-in-pipe systems have significantly reduced thermal loss and provide strength sufficient for a pipe laying process that includes pipe bending and pipe straightening.