Oscillating Rod Seal Assembly for Lateral Misalignment Control
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Solution Overview
Problem
Existing rod seal assemblies for machines with crossheads and sealed oscillating piston rods face challenges in maintaining effective sealing due to lateral movement of the piston rod, leading to misalignment and leakage of lubrication oil and gas.
Innovation Solution
A rod seal assembly comprising a seal housing, a rod seal, a bushing, and a rod seal base, where the rod seal base and bushing have an axial overlap, allowing for lateral movement alignment and reducing wear, while the rod seal's conical seat and shoulder portions enhance sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piston rod seal is made rigid to maintain sealing, then sealing performance is improved, but lateral misalignment and leakage increase due to inability to follow rod movement
Solution Approach 1:
The rod seal assembly is designed with dynamic characteristics, allowing the seal components to move laterally in response to piston rod oscillation. The seal housing and supporting parts are configured to follow the rod's lateral movements while maintaining sealing effectiveness, transforming the rigid seal into a dynamic system that adapts to operational conditions.
Solution Approach 2:
The patent modifies the physical parameters of the seal assembly by introducing lateral movement capability. The seal is designed with appropriate clearance and compliance in lateral directions, changing its stiffness characteristics to allow following motion while maintaining axial sealing function.
2Stability of the object's composition
If the seal housing is made rigid to support the seal, then structural stability is improved, but wear increases due to inability to accommodate lateral rod movement
Solution Approach 1:
The seal housing and supporting parts are designed with dynamic compliance in lateral directions while maintaining axial rigidity. This allows the housing to follow the piston rod's lateral oscillation, reducing friction and wear on the rod surface while preserving the structural stability needed for sealing support.
3Manufacturing precision
If the seal components are fixed in position, then alignment is maintained, but leakage increases due to inability to follow piston rod lateral movement
Solution Approach 1:
The seal components are designed with controlled lateral mobility rather than being completely fixed. The assembly can dynamically adjust its position to follow the piston rod's lateral oscillation, maintaining alignment precision through motion rather than through rigid fixation.
4Reliability
If lubrication is applied to improve sealing, then sealing performance is improved, but wear increases due to lubricant ingress into the high-pressure region
Solution Approach 1:
The patent extracts the lubrication function from the sealing function. The seal assembly is designed to provide sealing without relying on lubrication, preventing lubricant ingress into the high-pressure region while maintaining effective sealing through the dynamic seal design and appropriate material selection.
Data Source
AI summary
A rod seal assembly for a machine includes a crosshead and a sealed oscillating piston rod. The rod seal assembly includes a seal housing, a rod seal, a bushing and a rod seal base, wherein the rod seal, bushing and the rod seal base are annular and can be laterally moved in relation to the seal housing the housing axially supports the rod seal base, the rod seal base is adapted to be arranged around the piston rod and is provided with a base portion, wherein the base portion includes a lower axial surface directed in a first axial direction an upper axial surface directed in a second axial direction, wherein the lower axial surface abut the housing and the upper axial surface is provided with a rod seal seat, the rod seal is adapted to be arranged around the piston rod, and has a first end portion and a second end portion, wherein the first end portion is arranged to connect to the rod seal base in the first axial direction, and the bushing is arranged to abut the rod seal in the first axial direction, and the rod seal base and the bushing are arranged to have an axial overlap.