Cellular Glass Insulation Foam Annulus for Corrosion Prevention
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Solution Overview
Problem
Corrosion under insulation (CUI) occurs when moisture migrates between cellular glass insulation and metal pipes or vessels, leading to potential damage within the temperature range of 32° F (0° C) and 400° F (204° C, as existing insulation systems fail to effectively prevent moisture intrusion.
Innovation Solution
A foam is used to fill the annular spacer between the cellular glass insulation and the pipe or vessel, compressing to limit moisture intrusion and prevent CUI, while also providing sound attenuation properties, with preferred foam materials like silicone, polyimide, or melamine foams that do not degrade over the specified temperature range and can include hydrophobes or corrosion inhibitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cellular glass insulation is used to insulate pipes or vessels, then energy conservation and process control are achieved, but moisture can migrate between the insulation and the metal surface, causing corrosion under insulation (CUI)
Solution Approach 1:
A foam material is introduced as an intermediary substance between the cellular glass insulation and the metal pipe or vessel surface. This foam layer acts as a mediator that prevents direct contact and moisture migration pathways, thereby eliminating the CUI risk while maintaining the thermal insulation performance of the cellular glass.
Solution Approach 2:
The foam material is placed within the annular space between the cellular glass insulation and the metal surface, creating a nested structure where the foam is embedded in the gap. This nested configuration allows the foam to effectively block moisture pathways without disrupting the outer cellular glass insulation layer.
2Reliability
If a foam is added to fill the annular space between cellular glass insulation and the pipe, then moisture intrusion is limited and CUI is prevented, but the system complexity increases
Solution Approach 1:
The foam material is applied as a flexible filling material that conforms to the annular space between the cellular glass insulation and the pipe surface. This flexible application method simplifies installation compared to rigid barriers, and the foam's ability to compress and adapt to irregular gaps reduces the need for additional structural components.
Solution Approach 2:
The foam material's physical parameters (compressibility, density, thermal properties) are selected and adjusted to optimize its moisture-blocking performance while maintaining compatibility with the existing cellular glass insulation system. By tuning these parameters, the foam provides effective CUI prevention without requiring complex additional systems.
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 foam effectively reduces the risk of CUI and enhances sound attenuation by compressing to prevent moisture migration and incorporating corrosion inhibitors, ensuring the insulation system's integrity and performance across the specified temperature range.
Implementation Method 1
The foam, when compressed in the annular space, limits the intrusion of moisture under the surface of the cellular glass insulation
Implementation Method 2
The preferred foam composition utilized will not degrade over the CUI temperature range. In addition, the foam and cellular glass insulation system has several other key attributes including the attenuation of sound. In particular, the foam can be placed either at the annular space of the metal and cellular glass insulation
Implementation Method 3
the foam and cellular glass insulation system has several other key attributes including the attenuation of sound
Data Source
Figure 1a~1b
Figure 1c
Figure 2a~2b
AI summary
A cellular glass system for an outer surface of a pipe. An insulation layer surrounds the outer surface of the pipe. The insulation layer has an outer surface and an inner surface and comprises cellular glass. A foam fills an annular space between the outer surface of the pipe and the inner surface of the insulation layer and is configured to limit water intrusion into the annular space and attenuate sound. The system may also include another insulation layer and another foam layer between the two insulation layers.