Sealing Assembly Sequential Pressure Distribution
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Solution Overview
Problem
Sealing systems in high-pressure, dynamic environments like underground drilling face challenges in managing pressure differentials, leading to potential deformation, extrusion, or failure of sealing elements due to high radial forces.
Innovation Solution
A sealing assembly with a housing and internal valves that sequentially open at different pressure levels to distribute pressure across multiple sealing elements, reducing the differential pressure on each element and minimizing contact stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single sealing element is used to seal against high pressure, then sealing effectiveness is maintained, but the contact stress on the sealing element increases leading to deformation, extrusion, or failure
Solution Approach 1:
The patent divides a single sealing function into multiple sealing elements (first sealing element and second sealing element) arranged in series along the pressure gradient. Each sealing element handles a portion of the total pressure differential, reducing the contact stress on each individual element while maintaining overall sealing effectiveness. The sequential pressure distribution through multiple elements prevents deformation and extrusion that would occur with a single element under high differential pressure.
2Reliability
If multiple sealing elements are used to reduce contact stress, then seal reliability improves, but device complexity increases due to additional components and pressure control mechanisms
Solution Approach 1:
The patent employs pressure-actuated valves that automatically open and close based on the differential pressure across each sealing element. When the pressure differential across a sealing element reaches a predetermined threshold, its associated valve opens to equalize the pressure, reducing the contact stress on that element. This self-regulating mechanism eliminates the need for external control systems, complex actuation mechanisms, or continuous monitoring, thereby limiting the increase in device complexity while achieving reliable pressure distribution across multiple sealing elements.
3Reliability
If pressure differential across the seal increases to maintain sealing force, then sealing effectiveness is improved, but the radial force on the stationary sealing element increases causing deformation or leakage
Solution Approach 1:
The patent segments the total pressure differential into multiple smaller differentials across series-connected sealing elements. By distributing the pressure gradient across the first and second sealing elements, each element experiences reduced radial force while collectively maintaining the necessary sealing force to prevent leakage. This segmentation allows the system to handle high overall pressure differentials without subjecting any single sealing element to excessive radial loads that would cause deformation or failure.
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 solution effectively reduces the likelihood of seal failure by distributing high pressures across multiple sealing elements, maintaining effective sealing while preventing deformation and leakage.
Implementation Method 1
the contact stress between the seal and shaft increases with increasing differential pressure. As the pressure differential across the seal increases, the differential pressure acts on the unsupported area of the sealing element to create a high force
Implementation Method 2
the first relief valve and the second relief valve open sequentially so as to distribute pressure across the first sealing element and the second sealing element sequentially
Data Source
AI summary
A sealing assembly having a housing having a main cavity, a sealing unit configured to receive a rotatable shaft, and at least a first sealing element, and a second sealing element positioned uphole with respect to the first sealing element along the longitudinal axis. The sealing assembly includes a first valve carried by the housing and coupled to the first sealing element and the main cavity, and configured to open at a first pressure level. The sealing assembly further includes a second valve coupled to the second sealing element and the main cavity, and configured to open at a second pressure level higher than the first pressure level. The sealing assembly is configured such that pressure is distributed across the first and second sealing elements sequentially.