Carbon Mating Ring Seal Assembly for Lubricant Leakage Control
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Solution Overview
Problem
Typical rotating machines experience lubricant leakage and contamination issues, particularly when used in fuel cell air supply systems, leading to reduced efficiency and longevity due to hydrocarbon poisoning, and the use of lubricant-free bearings results in limited operating ranges and high costs.
Innovation Solution
The implementation of a rotating machine design featuring carbon rings and mating rings in seal assemblies, which prevent lubricant and contaminant leakage by positioning the carbon rings between the impeller wheels and mating rings, allowing for the use of lubricant-fed bearings while maintaining a contaminant-free environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If piston ring seals are used in rotating machines, then the structure is simple and cost-effective, but lubricant leakage and contamination occur
Solution Approach 1:
The seal assembly is divided into multiple functional components: a carbon ring that rotates with the shaft, a stationary mating ring with sealing surfaces, and a biasing mechanism. This segmentation allows each component to perform its specific function - the carbon ring provides a compliant sealing surface, the mating ring provides structural support and sealing contact, and the biasing mechanism maintains contact pressure - thereby improving sealing effectiveness while maintaining manufacturing simplicity
Solution Approach 2:
The carbon ring acts as an intermediary element between the rotating shaft and the stationary mating ring. It provides a compliant sealing surface that can accommodate misalignment and wear while maintaining effective sealing contact, thus preventing lubricant leakage without requiring complex sealing structures
2Object-affected harmful factors
If lubricant-free bearings (air foil bearings) are used to prevent hydrocarbon poisoning, then fuel cell protection is improved, but operating range is limited and cost increases
Solution Approach 1:
The harmful factor (lubricant) is extracted from the bearing system by using lubricant-free air foil bearings in the sections adjacent to the fuel cell. This eliminates hydrocarbon poisoning risk in the fuel cell air supply path. The patent applies this principle selectively - lubricant-free bearings are used only where needed (adjacent to fuel cell) while lubricant-fed bearings can be used in other sections, thus maintaining adaptability and operating range
Solution Approach 2:
Different bearing types are used in different locations based on local requirements. Air foil bearings (lubricant-free) are used in sections adjacent to the fuel cell where hydrocarbon contamination must be prevented, while lubricant-fed bearings can be used in other sections where lubrication is beneficial. This local differentiation allows the system to achieve both fuel cell protection and broad operating range
3Ease of manufacture
If piston ring seals are used, then manufacturing is easier, but contamination of impeller wheels occurs
Solution Approach 1:
The seal assembly is segmented into a rotating carbon ring and a stationary mating ring with biased contact surfaces. This segmentation creates a reliable barrier that prevents contaminant leakage while maintaining manufacturing simplicity through the use of standard components and assembly methods
Solution Approach 2:
The biasing mechanism in the seal assembly automatically maintains contact pressure between the carbon ring and mating ring surfaces, compensating for wear and manufacturing tolerances. This self-adjusting feature ensures continuous effective sealing without requiring complex control systems or frequent manual adjustment
Data Source
AI summary
A rotating machine includes a shaft, a first impeller wheel, and a second impeller wheel. The rotating machine also includes a first seal assembly including a first carbon ring disposed about the shaft, with the first carbon ring having a first carbon surface. The first seal assembly also includes a first mating ring disposed about the shaft, with the first mating ring having a first mating surface facing and configured to contact the first carbon surface. The rotating machine additionally includes a second seal assembly including a second carbon ring disposed about the shaft, with the second carbon ring having a second carbon surface. The second seal assembly also includes a second mating ring disposed about the shaft, with the second mating ring having a second mating ring surface facing and configured to contact the second carbon surface.