Multipart Packing Ring Wear Distribution
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Solution Overview
Problem
Conventional packing rings in piston compressors experience uneven wear between radially and tangentially cut segments, leading to reduced sealing effectiveness and increased leakage due to differential pressure distribution, causing the ring material to be used suboptimally and resulting in premature wear and loss of sealing integrity.
Innovation Solution
The design incorporates axial projections on sealing segments to widen the radially inner curved surface, forming separate wear gaps from ring segment ends, and includes tangential and radial end surfaces to ensure uniform sealing contact, along with circumferential grooves for pressure compensation and radial steps for enhanced flexibility, which reduces wear and maintains consistent sealing pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radially and tangentially cut packing rings are used in pairs, then wear gaps can be covered and sealing effectiveness is maintained, but the rings wear to differing degrees causing differential wear and potential rotation between rings
Solution Approach 1:
The packing ring is divided into multiple segments (radially cut and tangentially cut segments) that can move independently. This segmentation allows each segment to wear uniformly without causing differential wear between segments, while still maintaining the ability to cover wear gaps and preserve sealing effectiveness.
Solution Approach 2:
The packing ring segments are designed to be dynamically adjustable rather than fixed. The segments can move and reposition themselves during operation to accommodate wear, ensuring uniform wear distribution across all segments while maintaining sealing contact with the piston rod.
2Stress or pressure
If hose springs are used to press packing rings against the piston rod, then sealing pressure is maintained in the pressureless state, but the springs add device complexity and may not provide sufficient pressure at elevated pressures
Solution Approach 1:
The hose spring mechanism is completely removed from the packing ring design. Instead of using external springs to provide sealing pressure, the invention utilizes the high gas pressure differential itself to press the packing ring segments against the piston rod, eliminating the need for separate spring components and reducing device complexity.
Solution Approach 2:
The packing ring system becomes self-activating by utilizing the process gas pressure differential to automatically press the segments against the piston rod. The high-pressure gas on one side of the ring and low-pressure gas on the other side create a self-generating sealing force without requiring external spring mechanisms.
3Reliability
If additional metallic support rings are used between the packing ring and chamber disc, then extrusion of the packing ring is avoided, but the support rings increase device complexity and do not contribute to sealing
Solution Approach 1:
The packing ring segments serve multiple functions simultaneously: they provide sealing contact with the piston rod, prevent extrusion between segments through their interlocking design, and maintain structural integrity without requiring separate support rings. The segmented structure itself provides the support function that would otherwise require additional components.
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
This configuration reduces wear on sealing segments, maintains consistent sealing pressure, and prolongs the service life of the packing ring by distributing wear evenly and preventing the deterioration of the seal between tangential surfaces, thus minimizing leakage.
Implementation Method 1
an axial projection, which widens the radially inner curved circumferential surface of the sealing segment in the axial direction in the region of the projection, is provided on the sealing segments and the projection is arranged, viewed in the circumferential direction, between the ends of the ring segments so as to form first wear gaps set apart from the ends of the ring segments
Implementation Method 2
circumferential grooves for pressure compensation and radial steps for enhanced flexibility, which reduces wear and maintains consistent sealing pressure
Implementation Method 3
radial steps for enhanced flexibility, which reduces wear and maintains consistent sealing pressure
Data Source
AI summary
A multipart packing ring for sealing a piston rod of a compressor includes ring segments and sealing segments which are alternatingly arranged to form a ring. The ring segments include a curved main part and an axial shoulder and the sealing segments include a curved main part and an axial projection. The circumferential ends of the main part of the ring segments and the circumferential ends of the axial projection of the sealing elements face one another and define first wear gaps there-between.