Sandwich Piston Ring Structure for High-Pressure Compressor Wear
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Solution Overview
Problem
Existing piston rings for compressors are unsuitable for high-pressure applications beyond 200 bar due to pronounced cold flow and rapid wear, limiting their suitability for compressors with high final pressures.
Innovation Solution
A 'sandwich' piston ring design featuring a sealing ring supported by base and top rings with higher tensile strength, where the sealing ring is composed of a softer material with good shape adaptation capacity, allowing it to be held securely between the support rings and maintain a seal against the cylinder inner wall, even at high pressures and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-piece piston ring is used, then the structure is simple, but the piston ring exhibits pronounced cold flow under load resulting in rapid wear at high pressures
Solution Approach 1:
The piston ring is divided into three separate rings: a soft sealing ring and two harder support rings (base ring and top ring). The sealing ring is segmented into multiple segments by radial cuts, allowing it to adapt to the cylinder wall while being supported by the harder rings that prevent cold flow and wear.
Solution Approach 2:
The piston ring assembly uses composite materials with different properties: the sealing ring is made of soft material (e.g., PTFE) for good sealing and shape adaptation, while the support rings are made of harder materials (e.g., fiber-reinforced plastics or metal) with higher tensile strength to resist cold flow and wear at high pressures.
2Adaptability or versatility
If a soft sealing ring material is used, then shape adaptation capacity is good, but tensile strength is low causing rapid wear under high pressure
Solution Approach 1:
Different parts of the piston ring assembly have different material properties optimized for their specific functions: the sealing ring uses soft material for shape adaptation and sealing contact with the cylinder wall, while the support rings use hard materials with high tensile strength for structural support and wear resistance, creating local quality differentiation throughout the assembly.
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 design enables reliable operation at pressures over 500 bar and high temperatures, reducing leakage and wear by distributing pressure forces and protecting the sealing ring from damage during compression and expansion cycles.
Implementation Method 1
the sealing ring is composed of a softer material with a preferably good shape adaptation capacity
Implementation Method 2
the base ring and the top ring have a higher tensile strength than the sealing ring
Implementation Method 3
a piston ring which is arranged on the piston and rubs against the cylinder wall. This dry-running piston compressor
Data Source
AI summary
Piston ring having an endless base ring and sealing ring have a radially outwardly directed base ring face side. The sealing ring has a radially inwardly directed, circularly running sealing ring inner side with three tangential cuts separating three sealing ring segments are arranged in a circumferential direction (U). The base and sealing rings are arranged in succession in a longitudinal direction (L). A top ring is arranged to adjoin the sealing ring having a top ring has a radially outwardly directed top ring outer side and a radially inwardly directed top ring inner side. The top ring has, on the side opposite the sealing ring, a radially running return flow channel extending radially, the sealing face side protrudes in a radial direction beyond the top ring outer side and the base ring face side. The base and the top rings have a greater tensile strength than the sealing ring.