Dry Gas Seal Ring with Recirculating Grooves for Gas Containment
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Solution Overview
Problem
Dry gas seals in rotating machines face challenges in preventing process gas leakage to the atmosphere, particularly in applications where containment is critical, as existing designs may allow gas to escape through the seal interface.
Innovation Solution
A non-contacting dry gas seal design featuring a primary ring and a mating ring with a recirculating groove pattern that includes a channel and spiral grooves, where the gas is drawn from the inner or outer diameter and recirculated back, preventing leakage by maintaining a gas film without contact between the rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional dry gas seal design is used, then the seal allows controlled leakage of process gas to the atmosphere, but the design is simple in structure
Solution Approach 1:
The seal face is segmented into multiple functional zones through grooves and channels, creating distinct regions for gas recirculation, compression, and sealing. This segmentation allows the seal to contain gas more effectively while maintaining a manageable structural complexity through modular functional zones.
Solution Approach 2:
The invention introduces spiral grooves that extend in the axial dimension, creating a three-dimensional gas recirculation path. This adds an axial component to the traditionally radial gas flow, enabling gas to be recirculated through multiple passes and enhancing containment capability without proportionally increasing overall seal complexity.
2Loss of substance
If grooves are added to recirculate gas, then gas leakage is reduced, but the manufacturing complexity increases
Solution Approach 1:
Multiple groove patterns (spiral grooves, radial channels, circumferential grooves) are merged into a unified recirculation system on the seal face. This integration allows gas to follow a coordinated path through compression and recirculation zones, reducing leakage while the combined structure can be manufactured as a single integrated component rather than multiple separate parts.
Solution Approach 2:
The groove geometry parameters (depth, width, spacing, spiral angle) are optimized to achieve effective gas recirculation and compression. By carefully controlling these parameters, the seal achieves reduced gas leakage while the grooves remain manufacturable using standard machining processes, balancing performance with ease of manufacture.
3Reliability
If the gas film is maintained thicker to prevent contact, then leakage increases, but if the gas film is thinner, the risk of ring contact increases
Solution Approach 1:
The spiral grooves create a continuous gas recirculation path that constantly replenishes and maintains the gas film between the seal rings. This continuous action ensures the gas film remains at an optimal thickness, preventing ring contact while minimizing leakage through sustained gas pressure in the sealing interface.
Solution Approach 2:
The recirculating groove pattern creates a feedback mechanism where gas that would otherwise leak is redirected back through the compression zone. This feedback loop maintains gas pressure in the sealing interface, dynamically adjusting the gas film thickness to prevent contact while reducing net leakage to the atmosphere.
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 recirculating groove pattern effectively contains the gas within the seal interface, reducing leakage and enhancing the seal's ability to maintain a gas film, thereby ensuring efficient operation without allowing gas to escape to the atmosphere, improving the seal's reliability and longevity.
Implementation Method 1
The gas that is drawn into the grooves is compressed as is moves toward the radially inward ends (or tips) of the grooves. The compressed gas creates a pressure dam that causes the primary ring to 'lift off' from the mating ring to form a running gap
Implementation Method 2
The compressed gas creates a pressure dam that causes the primary ring to 'lift off' from the mating ring to form a running gap that is in the range of few microns (e.g., 3-10 μm)
Implementation Method 3
In operation, a layer of gas is developed between the two rings that forms a seal while allowing the rings to move relative to one another without contacting each other
Data Source
AI summary
A mating ring for use in a dry gas seal and a dry gas seal. The mating ring includes a face that defines an inner diameter and an outer diameter. The face includes: a channel formed therein disposed between the inner diameter and the outer diameter; one or more inlet channels formed in the face that extend from the inner diameter to the channel; and one or more spiral grooves in fluid communication with the channel that extend from the channel toward the inner diameter. Alternatively, the one or more inlet channels can extend from the outer diameter to the channel and one or more spiral grooves can extend from the channel toward the outer diameter.