Telescoping Jacket Seal Assembly for Dynamic Shaft Runout
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Solution Overview
Problem
Existing sealing assemblies for equipment with relatively movable shaft elements face challenges in preventing fluid loss due to dynamic runout, lateral deflection, and misalignment, as they struggle to maintain effective sealing contact under varying pressure conditions.
Innovation Solution
A sealing assembly featuring a backup ring with a pressure-retaining seal and self-aligning telescoping jackets, which applies fluid pressures to controlled locations on the backup ring to balance hydraulic forces, minimizing pressure-induced distortion and accommodating extrusion gaps, thereby maintaining effective sealing despite dynamic movements and misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the backup ring is made rigid to maintain sealing contact under pressure, then sealing effectiveness is improved, but the backup ring cannot accommodate dynamic runout and lateral deflection of the shaft element
Solution Approach 1:
The backup ring is designed with controlled flexibility to dynamically adapt its position and shape in response to shaft element deflection and runout while maintaining sealing contact. The ring can elastically deform within acceptable limits to follow shaft movements, resolving the contradiction between rigidity for sealing and flexibility for accommodation.
2Adaptability or versatility
If the backup ring is made flexible to accommodate shaft movement, then adaptability is improved, but pressure-induced distortion increases compromising sealing integrity
Solution Approach 1:
The material properties of the backup ring are carefully selected and engineered to provide optimal flexibility-stiffness balance. By controlling the modulus of elasticity and geometric parameters of the ring, it achieves sufficient flexibility to accommodate shaft movement while maintaining adequate structural stability to resist excessive pressure-induced distortion.
3Duration of action of stationary object
If the extrusion gap is minimized to prevent seal damage, then seal durability is improved, but the seal cannot accommodate thermal expansion and manufacturing tolerances
Solution Approach 1:
The backup ring is designed with built-in compensatory features that anticipate and cushion against potential extrusion damage from thermal expansion and manufacturing tolerances. The controlled flexibility and geometric design of the ring create a buffer zone that absorbs these variations while maintaining an effectively small extrusion gap to protect the seal.
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 prevents fluid loss by maintaining sealing contact and minimizing pressure-induced damage, ensuring the backup ring can align with lateral deflections and runout of the shaft element, thus enhancing the durability and reliability of the sealing assembly.
Implementation Method 1
applies the pressures of the first and second fluids to controlled locations on a backup ring in order to provide relative immunity to pressure-induced distortion, and in order to provide opposed axially acting hydraulic forces that substantially balance one another
Implementation Method 2
a pressure-retaining seal establishes sealing contact with the relatively movable shaft element to retain a pressurized first fluid
Data Source
Figure 1
Figure 1A
Figure 1B
AI summary
A sealing assembly includes a first machine component having a seal groove defined by radially oriented jacket support and energizer positioning walls and an energizer compressing wall that faces axially toward a second machine component. A seal located within the seal groove has an energizer element and a telescoping jacket. The jacket has a first leg portion having a jacket sealing surface facing toward the second machine component and an energizer contacting wall facing toward the energizer element. The energizer element is compressed between the energizer contacting and energizer compressing walls and loads the jacket sealing surface against the second machine component. A jacket second leg portion extends generally axially and has an energizer supporting wall facing toward the energizer element and a supported wall facing radially and adjoining the jacket support wall. The second leg portion is interposed between the energizer element and the jacket support wall.