Rotating Machine Seal Deterioration Detection by Pressure Comparison
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Solution Overview
Problem
Existing technologies do not provide a specific configuration for accurately determining the deterioration of outer seal rings in rotating machines like gas turbines.
Innovation Solution
A deterioration determination device and method that compare the pressures in different spaces within the gas turbine to detect when the sealing device has deteriorated, using pressure gauges and correction values to account for pressure losses in the sealing air discharge and supply passages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no pressure monitoring system is installed, then the device complexity is low, but the reliability of sealing device deterioration detection is insufficient
Solution Approach 1:
The patent introduces pressure monitoring devices as intermediaries to detect the pressure difference between the first space (between casing and bearing box) and the second space (inside bearing box). This pressure difference serves as an indirect indicator of sealing device deterioration, allowing reliable detection without direct observation of the sealing device itself.
Solution Approach 2:
The patent replaces direct mechanical inspection of the sealing device with a pressure-based detection system. By monitoring pressure differences in the gas spaces, the system substitutes mechanical deterioration assessment with a more reliable and non-intrusive pressure measurement approach.
2Measurement precision
If pressure loss in sealing air passages is not accounted for, then the measurement system is simpler, but the measurement precision of pressure difference is reduced
Solution Approach 1:
The patent implements feedback correction by continuously monitoring the actual pressure difference and comparing it with the standard pressure difference (calculated without pressure loss). The difference between these values is used to determine sealing device deterioration, effectively feedback-correcting for pressure loss effects in the sealing air passages.
Solution Approach 2:
The patent changes the measurement parameter from absolute pressure values to pressure difference values, and further refines this by introducing corrected pressure difference values that account for pressure loss. This parameter transformation allows for more precise deterioration detection by eliminating the confounding effect of pressure loss in the sealing air supply and discharge passages.
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
Accurately determines the deterioration of the sealing device, preventing high-temperature, high-pressure compressed air from entering the bearing space and reducing the risk of bearing failure.
Implementation Method 1
a determination part configured to determine that the sealing device has deteriorated when a first pressure corresponding to pressure of a first space formed between the casing and the bearing box is greater than a second pressure corresponding to pressure of a second space formed inside the bearing box
Data Source
AI summary
A deterioration determination device determines whether a sealing device of a rotating machine has deteriorated. The rotating machine includes: a rotor; a bearing rotatably supporting the rotor; a bearing box surrounding the bearing; a sealing air supply pipe; and a casing surrounding the bearing box. The casing separates the bearing box from an external space filled with high-temperature, high-pressure gas that has a higher temperature and higher pressure than the sealing air. The casing includes an inner peripheral surface on which the sealing device is arranged between the inner peripheral surface and an outer peripheral surface of the rotor. The deterioration determination device is configured to determine that the sealing device has deteriorated when a first pressure corresponding to pressure of a first space formed between the casing and the bearing box is greater than a second pressure corresponding to pressure of a second space formed inside the bearing box.