High-temperature heat shield assembly
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Solution Overview
Problem
Conventional metals and alloys used in vessels and piping for high-temperature applications, such as those involving molten salt, lose strength and corrode rapidly at temperatures above 600°C, limiting their reliability and requiring expensive high-nickel alloys for effective operation.
Innovation Solution
A hermetic heat shield bladder with a laminated structure of highly reflective thin metal foils, such as electropolished nickel, spaced by ceramic spacers within a corrosion-resistant sheath, provides effective radiative and conductive heat isolation, allowing the use of less expensive materials for vessels while maintaining reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional metals and alloys are used in vessels and piping for high-temperature applications, then the vessels can operate at high temperatures, but the metals lose strength and corrode rapidly at temperatures above 600°C
Solution Approach 1:
The patent employs a composite structure consisting of a high-temperature alloy liner (capable of withstanding 800°C) combined with a outer shell of conventional steel. This composite construction allows the vessel to operate at high temperatures while the expensive high-temperature alloy is used only where necessary (in direct contact with molten salt), reducing overall material costs while maintaining reliability and corrosion resistance at elevated temperatures.
2Reliability
If high-nickel alloys are used to resist corrosion at 800°C, then corrosion resistance is improved, but the material cost increases significantly
Solution Approach 1:
The patent applies local quality by using high-nickel corrosion-resistant alloys only in the liner that directly contacts the molten salt, where corrosion resistance is critical. The outer shell and supporting structures use conventional, less expensive steels. This localized application of expensive materials optimizes corrosion protection exactly where needed while dramatically reducing overall material costs compared to using high-nickel alloys throughout the entire vessel structure.
3Ease of manufacture
If a hermetic heat shield bladder is used to reduce vessel wall temperature, then less expensive materials can be used, but the device complexity increases
Solution Approach 1:
The patent uses a flexible bladder structure with a hermetic seal that can be fitted inside existing vessels. The bladder acts as a thermal barrier, keeping the vessel wall temperature below 500°C even when containing 800°C molten salt. This flexible film approach provides effective thermal isolation while being easier to install and replace compared to constructing an entirely new high-temperature alloy vessel, thus reducing material costs with acceptable complexity.
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 bladder effectively reduces the temperature of the vessel wall, enabling the use of affordable alloys like steel, while minimizing heat transfer and corrosion, thus reducing material costs and extending service life.
Implementation Method 1
The reflective foil layers within the bladder reflect thermal radiation to limit radiative heat transfer from the hot molten fluid to the vessel wall
Implementation Method 2
The inert gas filling the bladder reduces thermal conduction and convection to limit heat transfer from the hot molten fluid to the vessel wall
Implementation Method 3
The inert gas filling the bladder reduces thermal conduction and convection to limit heat transfer from the hot molten fluid to the vessel wall
Data Source
AI summary
A heat shield bladder includes first and second sheets of insulating material that form a bladder between the first and second sheets. At least one reflective foil is disposed within the bladder and a plurality of spacers are disposed within the bladder and positioned to space the at least one reflective foil from the first and second sheets of insulating material. Multiple reflective foils may be disposed within the bladder with spacers between each reflective foil. The heat shield bladder may be rolled into a tube shaped and used inside a pipe or formed into panels that may be used to line a vessel.