Double-Walled Pipe Insulation with Interlocking Joints
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Solution Overview
Problem
Existing double-walled fume pipes suffer from thermal bridges at joining zones due to discontinuity between insulating elements, leading to heat transfer and potential hazards, and require larger external diameters for heat dissipation, resulting in steel wastage and reduced fire resistance.
Innovation Solution
A connecting system with double-walled tubular modules featuring profiled male and female ends and a compressible ceramic fibre ring to ensure continuous insulation, preventing thermal bridges and enhancing fire resistance by using concentric sleeves made of refractory material, such as compacted rock wool, to maintain homogeneity and seal the gap between internal and external tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If discontinuous insulating elements are used in double-walled pipes, then assembly is simplified, but thermal bridges form at joining zones causing heat transfer and safety hazards
Solution Approach 1:
The insulating elements are pre-profiled at their ends with complementary geometric shapes (convex-concave or interlocking profiles) before assembly. This preliminary shaping enables the elements to automatically interlock and form continuous insulation when assembled, preventing thermal bridges without requiring complex assembly procedures or additional sealing materials.
Solution Approach 2:
The insulating elements have different geometric profiles at their ends: one end has a convex profile while the other has a concave profile (or complementary interlocking shapes). This local differentiation in geometry enables precise mating between adjacent elements, ensuring continuous insulation coverage at joining zones while maintaining overall assembly simplicity.
2Temperature
If larger external diameters are used for heat dissipation, then thermal management is improved, but steel usage increases and fire resistance is reduced
Solution Approach 1:
The continuous insulation layer extends uninterrupted through the entire length of the pipe, including through all joining zones between pipe sections. This continuity ensures consistent thermal performance along the entire pipe assembly, eliminating localized heat transfer paths that would otherwise require increased pipe diameter for compensation, thereby reducing steel usage while maintaining fire resistance.
3Object-affected harmful factors
If continuous insulation is achieved through overlapping sleeves, then thermal bridge prevention is improved, but device complexity increases
Solution Approach 1:
The continuous insulation is achieved by dividing it into discrete modular elements that are assembled in sequence. Each element has pre-formed profiled ends that enable simple overlapping or interlocking assembly, creating continuous insulation through repeated simple units rather than requiring a single complex continuous structure.
Solution Approach 2:
The insulating elements combine multiple functions into a single component: thermal insulation, mechanical joining between pipe sections, and continuous insulation coverage at joints. This merging eliminates the need for separate insulation materials and joining mechanisms, reducing overall device complexity while achieving thermal bridge prevention.
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 provides effective thermal insulation and prolonged fire resistance, ensuring safe fume evacuation and ventilation while minimizing steel usage and eliminating hazardous heat transfer points, achieving up to 120 minutes of fire resistance.
Implementation Method 1
use of a ring made of compressible ceramic fibre which on being inserted in the lower part of the joint, expands by pressing in a cushioning way between the layers of insulating material
Implementation Method 2
an insulating cladding 13 arranged internally of the gap formed between the external tube 12 and the internal tube 11
Implementation Method 3
the purpose of the gap in which insulating material is inserted is to prevent hazardous situations developing which are caused by any contact with the external tube, which must therefore necessarily remain at a low temperature, as well as maintaining the fumes at a high temperature
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A double-walled pipe for realising manufactured products for discharge of fumes and/or for extraction of vapours and/or for ventilation of rooms and/or for extraction of fumes in case of fire, by consecutively inserting a plurality of double-walled modules (10) that are joined in succession, comprising a plurality of modules, each comprising a respective double-walled tubular element; each double-walled tubular element extending between a male end (21) and a female end (22) and comprising an internal tube (11) and an external tube (12), arranged coaxially with respect to the preceding so as to define a double-walled structure; each tubular element comprising an internal gap arranged between said external tube (12) and said internal tube (11) in which an insulating cladding (13) is arranged, wherein ends of two joined tubular elements comprise respective recesses (16, 17) and projections extending towards the other tubular element and involving only a part of the thickness of the cladding (13) in a radial direction with respect to the tubular element, so that in the joined configuration a reciprocal overlapped joint of the recesses (16,17) with the projections is realised between each module and an adjacent module.