Sediment State Estimation via Diaphragm Resonance Frequency Shift
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Solution Overview
Problem
Conventional capacitance type pressure sensors suffer from zero-point errors due to sediment accumulation on the sensor diaphragm, requiring frequent replacements and labor-intensive manual inspection to detect sediment, which is only evident when significant enough to cause a zero-point shift.
Innovation Solution
A sediment state estimating apparatus that changes the power supply frequency of an AC power supply to detect the resonance frequency of the diaphragm, comparing it to an initial frequency to estimate the sediment state, allowing for early detection and classification of sediment accumulation levels without disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sediment accumulation is detected by disassembling and checking the diaphragm vacuum gauge, then the sediment state can be determined, but time and labor are required and the gauge must be replaced regardless of sediment state
Solution Approach 1:
The patent replaces manual mechanical inspection with an automated electrical measurement system. By applying an AC voltage at varying frequencies across the capacitor formed by the diaphragm and detecting resonance, the system automatically identifies sediment accumulation without disassembly, eliminating manual labor while maintaining detection accuracy.
Solution Approach 2:
The diaphragm vacuum gauge performs self-diagnosis through its own operational components. The sensor diaphragm and capacitor structure, originally designed for pressure measurement, are utilized to detect sediment accumulation on the diaphragm surface, allowing the device to monitor its own condition without external intervention or disassembly.
2Measurement precision
If sediment accumulation is detected by disassembly, then the sediment state is confirmed, but the diaphragm vacuum gauge needs to be replaced with a new one
Solution Approach 1:
The patent enables preliminary detection of sediment accumulation before it reaches critical levels that would require replacement. By continuously monitoring the resonance characteristics of the diaphragm, the system can identify sediment buildup in early stages, allowing for planned maintenance scheduling that minimizes operational disruption.
Solution Approach 2:
The system provides continuous feedback on the sediment accumulation state through resonance frequency measurements. This feedback loop allows operators to monitor the health of the diaphragm vacuum gauge in real-time and make informed decisions about maintenance timing, replacing the gauge only when necessary based on actual condition data rather than fixed replacement cycles.
3Extent of automation
If automatic estimation based on zero-point shift is used, then sediment accumulation can be detected automatically, but presence or absence of sediment cannot be determined unless a zero-point shift occurs
Solution Approach 1:
The patent utilizes vibrational resonance of the diaphragm to detect sediment accumulation. By applying AC voltage at varying frequencies and detecting the resonance frequency, the system can sense changes in the diaphragm's mechanical properties caused by sediment buildup, enabling detection before zero-point shifts occur.
Solution Approach 2:
The system detects sediment accumulation by monitoring changes in the resonance frequency parameter of the diaphragm-capacitor system. As sediment accumulates on the diaphragm surface, it alters the diaphragm's mass and stiffness characteristics, which manifest as measurable changes in resonance frequency, providing an early warning signal before pressure measurement errors occur.
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 the estimation of sediment state even in early stages of accumulation, reducing the need for frequent replacements and minimizing measurement errors by providing timely alerts for maintenance, thus optimizing the operation of semiconductor manufacturing equipment.
Implementation Method 1
a detecting portion (220) detecting a power supply frequency (rf2) at which the diaphragm (32) resonates when the power supply frequency of the AC power supply to be applied to the terminals (35, 36, 41, 45, and 46) is changed
Data Source
AI summary
The state of sediment can be estimated based on an initial power supply frequency at which a diaphragm resonates in an initial state in which sediment is not accumulated and a power supply frequency at which the diaphragm resonates after the sediment is accumulated, the state of the sediment can be estimated even in a stage in which the sediment is slightly accumulated on the diaphragm and a zero-point shift does not occur.