Mass Flow Controller Diagnostic via Differential Pressure Recording
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Solution Overview
Problem
Mass flow controllers using differential pressure type flow meters face challenges in diagnosing abnormalities without requiring additional time for diagnosis, leading to inefficient use of gas and limited precision in detecting clogging in differential pressure generation means.
Innovation Solution
A mass flow controller with a recording means to capture opening and closing pressure values during flow rate control transitions and a diagnostic means to detect abnormalities based on these values, allowing for quick and precise diagnosis of issues in the differential pressure type flow meter without separate diagnostic time, utilizing a mechanical pressure regulating valve to stabilize upstream pressure and enhance diagnostic precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate diagnostic procedures are implemented to detect clogging in differential pressure generation means, then measurement precision is improved, but loss of time increases and gas wastage occurs
Solution Approach 1:
The patent merges the diagnostic function with the normal flow control operation by utilizing pressure values already measured during flow rate control. The control means records opening pressure values when the flow control valve opens and closing pressure values when it closes, then compares these recorded values to detect abnormalities. This eliminates the need for separate diagnostic procedures while maintaining diagnostic precision.
Solution Approach 2:
The pressure measurement system serves dual purposes: it measures pressure for normal flow control operation and simultaneously performs diagnostic functions by analyzing the same pressure data for abnormalities. The control means acts as both a flow controller and a diagnostic device, making the system multi-functional and eliminating wasted time and gas.
2Measurement precision
If separate diagnostic procedures are implemented to detect clogging in differential pressure generation means, then measurement precision is improved, but loss of substance increases
Solution Approach 1:
The patent merges the diagnostic function with the normal flow control operation by utilizing pressure values already measured during flow rate control. The control means records opening pressure values when the flow control valve opens and closing pressure values when it closes, then compares these recorded values to detect abnormalities. This eliminates the need for separate diagnostic procedures while maintaining diagnostic precision.
Solution Approach 2:
The system performs self-diagnosis using its own operational data without requiring external diagnostic equipment or procedures. The control means uses the pressure values it already measures during normal operation to detect abnormalities, making the system self-sufficient and eliminating gas wastage associated with separate diagnostic tests.
3Device complexity
If traditional diagnostic methods using pressure attenuation data are used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent records opening pressure values and closing pressure values during normal flow control operations before any diagnostic analysis is needed. These pre-recorded pressure values are then used for abnormality detection by comparing them against reference values or each other, enabling precise clogging detection without requiring complex additional measurement systems.
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 efficient and precise diagnosis of abnormalities in differential pressure type flow meters, reducing gas wastage and improving reliability by integrating pressure recording and diagnostic functions within the control process, allowing for timely detection of issues in pressure sensors and differential pressure generation means.
Implementation Method 1
a flow meter (2) which measures a flow rate of fluid based on a value (P1) of first pressure that is pressure of the fluid on an upstream side of a differential pressure generation means (2c) interposed in a path (2d) of the fluid and a value (P2) of second pressure that is pressure of the fluid on a downstream side of the differential pressure generation means (2c)
Data Source
AI summary
A recording means records a value of pressure of fluid on a downstream side of a differential pressure generation means during a time period after a flow control valve open and control of a flow rate is started or after the flow control valve is closed and the control of a flow rate is stopped until a measured flow rate becomes stable, and a diagnostic means contrasts a controlled value acquired based in a value of the pressure of the fluid on the downstream side recorded by the recording means, with a controlled value when abnormality has not occurred, and diagnoses that abnormality has occurred in the flow meter when a difference between the both controlled values exceeds a threshold. Thereby, a mass flow controller and a diagnostic method which can simply diagnose generation of abnormality in a differential pressure type flow meter without requiring time only for performing the diagnosis.