Twin Piston Sealing Ring Assembly for Wear-Balanced Gas Sealing
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Solution Overview
Problem
Sealing ring assemblies in piston-cylinder systems face high wear rates and fracture risks, especially in the absence of lubricating oil, leading to unacceptable leakage and reduced operational life, due to uneven wear and pressure imbalances between front and rear rings.
Innovation Solution
A twin sealing ring assembly design featuring a first ring with an axially extending surface and a second ring with an inner radial surface interface, including a circumferential groove open to a low-pressure boundary and a pocket to receive high-pressure gas, along with anti-rotation features to prevent azimuthal movement and maintain even wear distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a self-lubricating material is used in the sealing ring, then the seal can operate without liquid lubricant, but the wear rate is relatively high leading to unacceptable leakage flow
Solution Approach 1:
The sealing ring is divided into multiple segments (first ring and second ring) that can move independently. This segmentation allows each ring to compensate for wear differently, maintaining sealing effectiveness even with self-lubricating materials that have higher wear rates. The gaps between segments can open and close to accommodate wear while preventing leakage.
Solution Approach 2:
The sealing ring uses dynamic gaps between segments that can open and close based on operating conditions. This dynamic structure allows the seal to adapt to wear over time while maintaining effective sealing. The gaps provide flexibility to compensate for material wear without requiring liquid lubrication.
2Duration of action of stationary object
If the sealing ring operates for extended periods, then economic benefits are achieved, but radial wear increases forming gaps that lead to unacceptable leakage
Solution Approach 1:
The ring is segmented into multiple pieces with gaps between them. As wear occurs over extended operation, these gaps can open to accommodate the worn surfaces while maintaining sealing contact. This allows the seal to continue functioning effectively throughout its operational life without developing unacceptable leakage paths.
Solution Approach 2:
The sealing ring design allows for wear to occur while maintaining sealing through the gap mechanism. When wear reaches certain limits, the entire assembly can be replaced as a unit, recovering the sealing function. The segmented design maximizes the usable life before replacement is needed.
3Reliability
If pressure forces act on the sealing ring, then sealing function is achieved, but uneven wear occurs between front and rear rings
Solution Approach 1:
The sealing system uses multiple independent rings (front ring and rear ring) that experience pressure forces separately. This segmentation allows each ring to wear uniformly under the applied pressure, rather than creating uneven wear patterns across a single ring. The pressure-induced wear is distributed across multiple components.
Solution Approach 2:
The design accepts asymmetric wear patterns between front and rear rings as normal operation, with each ring designed to accommodate its specific wear characteristics. The overall system maintains sealing effectiveness despite the asymmetric wear distribution between different ring positions.
4Duration of action of moving object
If gaps form due to radial wear, then wear accommodation is achieved, but the gap opens by 2*pi*radial wear causing unacceptable leakage
Solution Approach 1:
The sealing ring is divided into segments with gaps between them. As radial wear occurs, these gaps can open to accommodate the worn surfaces. The segmented design ensures that the gap opening due to wear does not create continuous leakage paths, as the gaps are controlled and can be closed by elastic recovery or pressure forces.
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 design reduces wear rates, minimizes fracture risks, and maintains effective sealing by balancing radial pressure forces and preventing uneven wear, thereby extending the operational life of the seal without the need for liquid lubricants.
Implementation Method 1
a self-lubricating material in which the wear rate is relatively high
Implementation Method 2
a groove extending circumferentially along at least one of the radially outward surface of the extension and the inner radial surface of the second ring... a pocket that extends azimuthally in an outermost radial surface of the second ring. The pocket is configured to receive gas from a high-pressure boundary
Data Source
AI summary
The present disclosure provides a sealing ring assembly having a first ring and a second ring, configured to seal a high-pressure region from a lower pressure region of a piston and cylinder device. Accordingly, the sealing ring assembly includes a high-pressure boundary and a low-pressure boundary. Each ring may be segmented, and the first and second rings interface along a surface. Along the surface at the interface, a groove open to the lower pressure region aids in pressure locking the sealing ring assembly. A pocket in the second ring allows for high pressure gas to aid in balancing radial forces on the sealing ring assembly. As the sealing ring wears, the first and second rings remain engaged with one another.