Wear-compensating Sealing Ring Assembly for Reciprocating Piston Systems

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Solution Overview

Problem

Existing segmented sealing ring assemblies in reciprocating piston systems experience uneven wear rates due to differential pressure, leading to preferential wear and eventual leakage, as the sealing ring wears faster than the cover ring, causing a gap to form and compromising the seal.

Innovation Solution

A seal assembly design featuring a sealing ring with a sealing ring gap and a cover ring with an annular recess, where the sealing ring is seated in the recess, ensuring the radial recess width is equal to or greater than the sealing ring width in one region and less in another, preventing the overlap of gaps and maintaining contact stress balance between the rings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a segmented seal assembly with cover ring and sealing ring is used, then the seal assembly can be designed with modular components, but the rings wear at different rates due to differential pressure causing preferential wear

Engineering Contradiction:
Improvemodular component designVSAvoiduniform wear rate
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The seal assembly is divided into a cover ring and a sealing ring, each with gaps positioned at different angular locations. This segmentation allows independent design optimization while maintaining modular assembly benefits, resolving the contradiction by enabling uniform wear distribution through strategic gap positioning.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cover ring and sealing ring are designed with asymmetric gap positions relative to each other. The sealing ring gap is positioned at a different angular location than the cover ring gap, creating an asymmetric configuration that distributes contact stress more evenly across both rings during reciprocating motion, thereby preventing preferential wear.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If the sealing ring is exposed to full pressure differential at the gap location, then the sealing function is maintained, but the contact stress on the sealing ring increases causing higher wear rate

Engineering Contradiction:
Improvesealing functionVSAvoidcontact stress resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The cover ring gap is positioned to provide preliminary sealing support before the sealing ring gap location. This preliminary action distributes the pressure differential more evenly, reducing the peak contact stress on the sealing ring while maintaining the sealing function throughout the reciprocating cycle.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The cover ring acts as an intermediary element that shares the sealing load with the sealing ring. By positioning the cover ring gap at a different angular location, the cover ring provides sealing support during portions of the reciprocating cycle, thereby mediating the pressure differential and reducing contact stress on the sealing ring.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the radial recess width equals the sealing ring width in one region and is less in another, then gap overlap is prevented and contact stress is balanced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvecontact stress balanceVSAvoidradial recess width tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The annular recess in the cover ring is designed with varying radial width to match the sealing ring width in specific angular regions. This local quality variation ensures that the recess provides optimal support where needed while preventing gap overlap, balancing contact stress distribution without requiring uniform high precision throughout the entire component.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The radial width parameter of the annular recess is deliberately varied in different angular regions rather than maintaining a constant width. This parameter change allows the recess to provide enhanced support in regions where the sealing ring requires it most, while reducing material and simplifying manufacturing in regions where full support is not required.

Inventive Principle:
Principle #35Parameter changes

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 design extends the operational life of the seal assembly by minimizing differential wear rates and preventing gap formation between the sealing and cover rings, maintaining a consistent seal over time and reducing leakage.

Implementation Method 1

the rate of wear of the seal assembly rings is proportional to the contact stress the respective ring experiences when brought into contact with the sliding surface

Methodology Applied
Scientific EffectWear: Wear

Implementation Method 2

The higher the contact stress, the higher the consequent rate of wear

Methodology Applied
Scientific EffectContact stress: Stress Relaxation

Data Source

PatentEP2713080B1Wear-compensating sealing ring assembly
Publication Date: 2016.09.07 AIR PROD & CHEM INC
  • EP2713080B1 patent drawingFigure 1A~1B
  • EP2713080B1 patent drawingFigure 2A~2B
  • EP2713080B1 patent drawingFigure 3A~3B

AI summary

A seal assembly for a reciprocating piston system is provided that compensates for uneven wear rates between the ring components of the seal assembly by initially sizing a portion of the width of the sealing ring larger than the width of the annular recess in the cover ring, this portion at least partially overlapping the gap in the cover ring but not the gap in the sealing ring.