Dry Gas Seal Sensing for Low-Speed Lift-Off and Touch-Down
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Solution Overview
Problem
Current dry gas seal monitoring systems are unable to effectively monitor the low speeds at which lift-off and touch-down events occur, limiting their ability to detect seal degradation and prevent machine downtime, as they are not configured to sense the relatively low rotational speeds associated with these events.
Innovation Solution
A dry gas seal monitoring system that includes an acoustic emissions sensor and a speed sensor, along with a processor, to detect the operational conditions of the seal faces, such as lift-off and touch-down, by sensing the rotational speed of the shaft and associating it with the occurrence of these events, allowing for the establishment of baseline speeds and comparison to subsequent occurrences to assess seal health.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current dry gas seal monitoring systems are used, then they can monitor seal operating conditions, but they are unable to effectively monitor low speeds at which lift-off and touch-down events occur
Solution Approach 1:
The patent changes the operational parameters of the speed sensor to enable detection at low rotational speeds (below 1000 RPM). By adjusting the sensor's sensing threshold and calibration parameters, the system can accurately detect lift-off and touch-down events that occur at previously undetectable low speeds, thereby resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The system establishes baseline speed values for lift-off and touch-down events during normal operation. These baseline values are stored and used for comparison during subsequent monitoring, enabling the system to reliably detect these events even at low speeds. This preliminary characterization of normal operation allows the monitoring system to identify deviations that indicate seal degradation.
2Reliability
If baseline speeds are established and compared to subsequent occurrences, then seal degradation can be detected, but the system requires continuous monitoring and data processing
Solution Approach 1:
The monitoring system continuously compares current rotational speed measurements against established baseline values for lift-off and touch-down events. When deviations exceed predetermined thresholds, the system generates alerts or shutdown signals. This feedback mechanism enables reliable seal degradation detection by identifying changes in the characteristic speeds of these events, while maintaining manageable system complexity through straightforward comparison logic.
3Loss of information
If acoustic emissions sensor and speed sensor are integrated, then real-time assessment of seal operating conditions is enabled, but the device complexity increases
Solution Approach 1:
The patent integrates an acoustic emissions sensor with a speed sensor to create a combined monitoring system. The acoustic sensor detects characteristic sounds associated with lift-off and touch-down events, while the speed sensor simultaneously measures rotational speed. By merging these two sensing modalities and correlating their outputs, the system achieves comprehensive real-time assessment of seal operating conditions without requiring separate independent monitoring systems, thus managing complexity through functional integration.
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
Enables accurate monitoring of seal face degradation and early detection of potential failures, reducing downtime by providing real-time assessment of seal operating conditions and allowing for proactive maintenance.
Implementation Method 1
The acoustic emissions sensor may be configured to sense when the first seal face and the second seal face are in an operational condition relative to one another
Implementation Method 2
The speed sensor may sense the speed of the rotatable shaft at speeds below one thousand (1,000) rotations per minute (RPMs)
Data Source
AI summary
A system and method for monitoring a dry gas seal positionable between a stationary housing and a rotatable shaft. A plurality of sense elements may rotate in response to the rotation of the rotatable shaft and a speed sensor may sense the speed of the rotatable shaft at speeds below one thousand rotations per minute based on sensing the plurality of sense elements. An acoustic emissions sensor may sense when a first seal face and a second seal face forming a seal interface of the dry gas seal are in an operational condition relative to one another. A processor may receive output signals from the speed sensor and the acoustic emissions sensor, and may establish an operating condition of the dry gas seal based on the signal from the speed sensor when the first seal face and the second seal face reach the operational condition relative to one another.