Mechanical Seal Wear Geometry for Stable Sealing Gap
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Solution Overview
Problem
Mechanical seal assemblies with hard-soft pairings face challenges in determining the replacement time for worn-out slide rings due to changing stress and relief in the sealing gap caused by wear, which affects the wear behavior over time.
Innovation Solution
A mechanical seal assembly with a sliding ring having a non-cylindrical wear area, where the outer and/or inner diameters change in the axial direction, allowing for selective adjustment of wear behavior based on existing wear and changing load forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a ring-cylindrical wear area with constant outer and inner diameters is used, then the manufacturing is simple and inexpensive, but the wear behavior changes over time due to stress and relief changes in the sealing gap
Solution Approach 1:
The wear area is designed with non-uniform geometry where the cross-sectional area varies in the axial direction. Specifically, the wear area comprises a first section with a first cross-sectional area and a second section with a second cross-sectional area, where the cross-sectional areas differ. This local variation in geometry allows different regions of the wear area to experience different stress distributions, compensating for stress and relief changes in the sealing gap that occur during operation, thereby maintaining stable wear behavior throughout the service life of the mechanical seal assembly.
2Adaptability or versatility
If the wear area has a non-cylindrical region with changing cross-sectional area, then the wear behavior can be adapted to changing load forces, but the manufacture cost increases
Solution Approach 1:
The wear area incorporates a non-cylindrical region where the cross-sectional area changes in the axial direction, creating zones with different wear characteristics. The first section has a larger cross-sectional area to handle higher initial loads, while the second section has a reduced cross-sectional area for later operational phases. This local geometric variation enables the wear area to adapt to changing load forces and stress conditions during operation, optimizing wear behavior without requiring complete redesign of the entire slide ring.
Solution Approach 2:
The wear area is divided into multiple sections (first section and second section) with distinct cross-sectional areas. This segmentation allows each section to be optimized for specific operational phases, with the first section handling initial running-in and higher load conditions, and the second section managing steady-state operation. The segmented design provides adaptability to varying load forces while maintaining a relatively simple overall structure that can be manufactured cost-effectively.
3Reliability
If a hard-soft material pairing is used in slide rings, then minimum leakage can be achieved, but the replacement time determination becomes difficult due to changing wear behavior
Solution Approach 1:
The non-uniform cross-sectional area design of the wear area creates a predictable and controlled wear progression pattern. As the softer slide ring wears, the changing geometry of the wear area (with its varying cross-sectional areas in different sections) produces characteristic changes in sealing performance and load distribution that can serve as feedback indicators. This allows operators to monitor wear progression and determine replacement timing more accurately, despite the hard-soft material pairing causing differential wear.
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 enables targeted wear behavior adaptation, maintaining a constant sealing gap and extending the service life of the mechanical seal assembly by allowing for timely replacement based on wear indicators.
Implementation Method 1
The sliding surface of this wearing slide ring is located at the wear area. The wear area of this wearing slide ring has an at least partially non-cylindrical region in the axial direction
Data Source
AI summary
The invention relates to a mechanical seal assembly comprising a mechanical seal (2) having a rotating slide ring (3) with a sliding surface (3a) and a stationary slide ring (4) with a sliding surface (4a) defining a sealing gap (5) therebetween, wherein one of the slide rings is designed as a wearing slide ring and has a hardness lower than the other one of the slide rings, wherein the wearing slide ring has a base area (30a) and a wear area (30b), and wherein the wear area (30b) has an at least partially non-cylindrical area in the axial direction (A) of the mechanical seal assembly.