Spring-Energized Lip Seals for Extreme Temperature Leakage Control
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Solution Overview
Problem
Conventional seal designs experience thermal contraction or expansion issues at extreme temperatures, leading to loss of sealing contact and effectiveness in cryogenic and high-temperature applications, particularly due to differing shrink rates between plastic and metal materials.
Innovation Solution
The use of spring energized lip seals and assemblies with additional support components, such as rigid components, multiple springs, and housing configurations that accommodate thermal expansion or contraction, including a locking ring with leaf springs and support rings, to maintain sealing contact across extreme temperature ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional seal designs are used in extreme temperature applications, then the seal assembly is simple in structure and easy to manufacture, but the seal experiences thermal contraction or expansion causing loss of sealing contact and reduced reliability
Solution Approach 1:
The patent introduces spring energizers that provide dynamic compensation for thermal contraction and expansion. The springs allow the seal assembly to adapt its configuration in response to temperature changes, maintaining sealing contact through elastic deformation rather than rigid structural constraints.
Solution Approach 2:
The patent explicitly addresses thermal expansion and contraction by designing the seal assembly to accommodate these dimensional changes. The spring energizers are configured to counteract the effects of thermal expansion in high-temperature applications and thermal contraction in cryogenic applications, ensuring continuous sealing contact despite material dimensional changes.
2Ease of manufacture
If plastic materials are used for the sealing component, then the seal is easy to manufacture and cost-effective, but the plastic shrinks about ten times more than metallic materials in cryogenic temperatures causing sealing failure
Solution Approach 1:
The patent changes the physical parameters of the sealing system by introducing spring energizers that compensate for the excessive shrinkage of plastic materials at cryogenic temperatures. The springs provide mechanical force to counteract the thermal contraction, allowing plastic sealing components to maintain effective sealing contact despite their high shrinkage rate.
Solution Approach 2:
The patent creates a composite sealing assembly combining plastic sealing components with metal spring energizers. This composite structure leverages the manufacturing advantages of plastic while incorporating the thermal stability of metal springs to compensate for differential thermal contraction between the plastic seal and metal shaft or bore.
3Reliability
If multiple spring energizers are added to counteract seal shrinkage, then the sealing reliability improves, but the device complexity and number of components increases
Solution Approach 1:
The patent segments the sealing function into multiple independent spring energizers, each responsible for maintaining contact at specific sealing interfaces. This segmentation allows for targeted compensation of thermal effects at different locations within the seal assembly, improving overall reliability while keeping each individual spring component simple and manageable.
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
These designs effectively counteract thermal shrinkage or expansion, ensuring consistent sealing performance across a wide temperature range from -272.778 °C to 232.222 °C by providing additional sealing support and maintaining contact between plastic and metal surfaces, thus preventing leakage.
Implementation Method 1
a first loading spring biasing against a first surface of the second section and against the inside flange; a second loading spring biasing against a second surface of the second section and against the outside flange
Implementation Method 2
Conventional seal assembly designs, or simply called seals, may experience thermal contraction or expansion under extreme temperatures
Implementation Method 3
Conventional seal assembly designs, or simply called seals, may experience thermal contraction or expansion under extreme temperatures
Data Source
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AI summary
Seal assembly designs for extreme temperatures that include material and structural designs to counteract sealing component shrinkage or expansion caused by thermal expansion or contraction. Provisions can be included to increase sealing stress along the outer seal lip (122) of the seal assembly for low temperature applications where shrinkage can be an issue and to increase sealing stress along the inner seal lip (120) of the seal assembly (108) for high temperature applications where expansion can be an issue.