Dynamic Seal Purge Gas Control for Vacuum Leakage Prevention
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Solution Overview
Problem
In vacuum systems, adverse pressure differentials can lead to leakage past dynamic seals, contaminating lubricants and potentially damaging vacuum pump components, especially when the operating pressure inside the vacuum chamber is higher than outside, and existing control methods are inadequate to manage this issue effectively.
Innovation Solution
A method and controller for dynamically controlling the supply of purge gas to maintain a positive pressure differential across the dynamic seal by adjusting the purge gas flow based on real-time pressure and rate of change measurements, ensuring the supply is optimized relative to the operating pressures on both sides of the seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If purge gas is supplied to maintain positive pressure differential across the dynamic seal, then leakage past the seal is reduced, but the device complexity increases due to pressure monitoring and control mechanisms
Solution Approach 1:
The system continuously monitors the pressure differential across the dynamic seal and adjusts the purge gas supply rate accordingly. When the pressure differential decreases below a threshold, the controller increases purge gas flow to maintain the positive pressure gradient, preventing process material leakage while adapting to changing operating conditions.
Solution Approach 2:
The control system automatically regulates the purge gas supply based on real-time pressure differential measurements without requiring manual intervention. The controller adjusts the purge gas flow rate to maintain optimal seal performance, making the system self-regulating and reducing the need for external monitoring and adjustment.
2Reliability
If purge gas supply is increased to prevent leakage, then seal performance improves, but energy consumption increases
Solution Approach 1:
The purge gas supply rate is dynamically adjusted based on the actual pressure differential across the seal rather than maintaining a constant high flow rate. The controller modulates the purge gas flow to match the minimum required to maintain positive pressure differential, reducing unnecessary energy consumption while ensuring seal effectiveness.
Solution Approach 2:
The system changes the purge gas flow rate parameter in response to varying pressure differential conditions. When the pressure differential is sufficient, the purge gas flow is reduced; when the pressure differential decreases, the flow is increased to maintain seal performance, optimizing energy usage across different operating conditions.
3Reliability
If continuous purge gas supply is maintained to prevent leakage, then seal reliability is improved, but loss of substance increases
Solution Approach 1:
The purge gas supply is applied periodically or intermittently based on the actual need to maintain positive pressure differential across the seal. The controller monitors pressure differential and activates purge gas supply only when the differential decreases below a threshold, rather than maintaining continuous supply, thereby reducing purge gas consumption.
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 approach significantly reduces fluid leakage and maintains a stable vacuum performance by actively managing pressure differentials, preventing contamination of lubricants and other components, and ensuring the longevity of vacuum pump components.
Implementation Method 1
a pressure differential may be established which promotes leakage past the dynamic seal... The resulting pressure differential is referred to herein as an adverse pressure differential
Data Source
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AI summary
Aspects of the present invention relate to method of controlling a supply of purge gas to reduce leakage past a dynamic seal (10). The dynamic seal (10) comprising at least a first sealing member (12-1) having opposing first and second sides (12-1A, 12-1B). A pressure differential (ΔP) is determined between a first operating pressure (P1) on the first side of the first sealing member (12-1) and a second operating pressure (P2) on the second side of the first sealing member (12-1). The supply of purge gas to the second side of the first sealing member (12-1) is controlled in dependence on the determined pressure differential (ΔP). Aspects of the invention relate to a controller (23) for controlling a supply of purge gas; a dynamic sealing system (1) for a vacuum system (2); and a vacuum system (2).