Flexible Pipe End-Fitting Seal Assembly for Leak-Tight Pressure Changes
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Solution Overview
Problem
Existing end-fitting and unbonded flexible pipe systems require substantial compressive forces to maintain sealing integrity, which can be challenging due to dimensional changes and variations during production, installation, and operation, especially under shifting pressures and temperatures.
Innovation Solution
The system employs a seal casing with at least two ring-shaped sealing elements of different hardness levels (Shore D 40-70 and Shore A 80-100 IRHD) that form line contacts to provide self-sealing properties without permanent compressive forces, using polymer materials like polyolefins and fluoroelastomers for efficient sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substantial compressive forces are applied to maintain sealing integrity, then sealing reliability is improved, but dimensional changes and variations during production, installation, and operation are exacerbated
Solution Approach 1:
The patent changes the hardness parameter of the sealing element by selecting a material with Shore A hardness of 80-100 IRHD. This high hardness allows the sealing element to maintain its shape and sealing contact without requiring substantial compressive forces, thereby resolving the contradiction between sealing reliability and dimensional stability.
Solution Approach 2:
The patent uses a composite sealing system comprising a sealing element made from high-hardness polymer material (Shore A 80-100 IRHD) that combines rigidity for maintaining shape with sealing capability. This material composite enables the sealing element to resist dimensional changes while maintaining reliable sealing contact.
2Reliability
If permanent compressive forces are used to ensure sealing, then sealing reliability is improved, but the complexity of the end-fitting structure increases
Solution Approach 1:
The sealing element is designed to be self-sealing through its high hardness (Shore A 80-100 IRHD), which enables it to maintain sealing contact without requiring external compressive forces or complex adjustment mechanisms. The element serves itself by maintaining its shape and sealing pressure inherently.
Solution Approach 2:
By changing the hardness parameter to Shore A 80-100 IRHD, the sealing element achieves self-maintaining sealing contact without requiring additional compressive force application mechanisms, thereby simplifying the end-fitting structure while maintaining sealing reliability.
3Adaptability or versatility
If soft sealing materials are used to accommodate dimensional changes, then adaptability is improved, but sealing reliability under varying pressures and temperatures deteriorates
Solution Approach 1:
The patent changes the hardness parameter to Shore A 80-100 IRHD, which provides sufficient rigidity to maintain sealing contact under varying pressures and temperatures while still allowing minimal deformation to accommodate dimensional changes. This parameter optimization resolves the contradiction between adaptability and reliability.
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 configuration achieves reliable and cost-effective sealing, maintaining leak-tightness under varying pressures and temperatures, eliminating the need for excessive compressive forces and ensuring durability and long-lasting performance.
Implementation Method 1
a first ring shaped sealing element concentrically arranged around the internal pressure sheath in the recess such that the surface of the first ring shaped sealing element at least forms a line contact with the internal pressure sheath
Implementation Method 2
a second ring shaped sealing element concentrically arranged around the internal pressure sheath in the recess such that the surface of the second ring shaped sealing element at least forms a line contact with the surface of the seal casing and forms a line contact with the surface of the first ring shaped sealing element and wherein the hardness of the first ring shaped sealing element is different from the hardness of the second ring shaped sealing element
Data Source
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AI summary
The present invention relates to an assembly of an end-fitting and an unbonded flexible pipe, where the unbonded flexible pipe comprises from the inside and out an internal pressure sheath, at least one armor layer and an outer sheath, the end-fitting further comprises sealing means. The sealing means comprises a seal casing (30) concentrically arranged around the internal pressure sheath (11), the seal casing (30) comprises a recess (31) in which a first sealing element (41) is concentrically arranged around the internal pressure sheath (11) such that the surface of the first sealing element (41) at least forms a line contact with the internal pressure sheath (11), and a second sealing element (42) is concentrically arranged around the internal pressure sheath (11) in said recess (31) such that the surface of the second sealing element (42) at least form a line contact with the surface of the seal casing (30) and form a line contact with the surface of the first sealing element (41) and wherein the Shore D hardness of the first sealing element (41) is in the range of 40 to 70 when measured according to ASTM 2240; and the Shore A hardness of the second sealing element (42) is in the range of 80 IRHD to 100 IRHD when measured according to ISO 48N.