Pressure-Activated Annular Seal for High-Temperature Melt Leakage
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Solution Overview
Problem
Existing sealing devices for fluid passages, particularly in equipment processing plastic melts, face challenges with high temperatures exceeding 250°C and leakage issues due to the limitations of PTFE seals and designs with large expansion slots that allow plastic melt penetration.
Innovation Solution
A flexible annular sealing element with a radially expanding design and inclined sealing surfaces, which expands radially and axially under fluid pressure to ensure reliable sealing by abutment against both components, and a secondary sealing element with a copper alloy to compensate for thermal expansion and material tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If PTFE sealing elements are used in high-temperature applications, then the sealing device can operate at elevated temperatures, but the sealing reliability deteriorates due to material limitations and leakage susceptibility
Solution Approach 1:
The sealing element material is changed from PTFE to a metal alloy (e.g., Inconel, Hastelloy, or stainless steel), fundamentally altering the material parameters to withstand temperatures exceeding 250°C while maintaining sealing reliability. This material substitution enables the sealing device to operate in high-temperature environments without the degradation and leakage issues associated with PTFE.
2Stability of the object's composition
If expansion slots are designed with large free slot widths, then the sealing element can accommodate thermal expansion, but sealing performance deteriorates due to plastic melt penetration through the expansion slot
Solution Approach 1:
The sealing element incorporates a dynamically adjustable expansion slot design where the slot width can vary based on operating conditions. The slot includes features such as inclined sealing surfaces that progressively close the opening under fluid pressure, allowing the slot to maintain openness for thermal expansion while dynamically sealing against melt penetration during operation.
Solution Approach 2:
The fluid pressure that would normally force melt through the expansion slot is converted into a beneficial sealing force. The inclined sealing surfaces are designed so that the pressure of the plastic melt itself pushes the sealing element against the sealing surface, closing the expansion slot and preventing penetration, thereby transforming the harmful pressure into a useful sealing mechanism.
3Device complexity
If a simple sealing design is used, then the device complexity is reduced, but sealing reliability deteriorates in high-temperature applications
Solution Approach 1:
The sealing element is designed to be self-regulating and self-sealing. The expansion slot automatically adjusts its opening based on thermal conditions, while the inclined sealing surfaces automatically close the slot under fluid pressure without requiring external control mechanisms. This self-service design achieves reliable high-temperature sealing through the inherent properties of the sealing element itself, avoiding complex external sealing 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
This design provides a simple and reliable sealing action, effectively preventing fluid leakage at high temperatures by ensuring full contact and compression of the expansion slot, enhancing the sealing effect and maintaining integrity in high-temperature applications.
Implementation Method 1
radial and resulting axial pressure of the fluid passing through there will cause the first sealing element to expand in the radial direction
Implementation Method 2
the first sealing element is of a flexible design and has its expansion slot formed in such a way that radial and resulting axial pressure of the fluid passing through there will cause the first sealing element to expand
Implementation Method 3
a secondary sealing element with a copper alloy to compensate for thermal expansion and material tolerances
Data Source
AI summary
The invention relates to a sealing device of a system for sealing a fluid passage from a first component (1) to a second component (2), comprising at least one first sealing element (3) which is of an annular design to allow fluid to pass through it, includes at least one expansion slot (4) and has a first sealing surface (5) sealingly associated with the first component (1) and has a second sealing surface (8) sealingly associated with the second component (2), said at least one first sealing element (3) being flexible and said expansion slot (4) being designed in such a way that radial and resultant axial pressure of the fluid passing through there will cause the first sealing element (3) to expand in the radial direction and thus press radially in the direction against the first component (1), with said first sealing surface (5) with the expansion slot (4) being sealed against the first component (1) by abutment in the direction of the latter, and in such a way that the first sealing element (3) will press axially in the direction against the second component (2), with the second sealing surface (8) with the expansion slot (4) being sealed against the second component (2) by abutment in the direction of the latter.