Flow Rate Control Valve Closure for Restriction Abnormality Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In pressure-type flow rate control devices, it is challenging to accurately control flow rates when clogging or shape changes occur in the micro opening of the restriction portion, and detecting abnormalities in valves and restriction portions is difficult, requiring a simple and effective method for stable operation.
Innovation Solution
The method involves using a flow rate control device with pressure sensors on both the upstream and downstream sides of the restriction portion, changing the control and downstream valves from an open to a closed state, measuring upstream and downstream pressures, and calculating convergence pressures and times to detect abnormalities by comparing these values with reference data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a pressure sensor is provided only on the upstream side of the restriction portion, then the device complexity is reduced, but the measurement precision of flow rate decreases when the critical expansion condition is not satisfied
Solution Approach 1:
The patent applies multi-functionality by making the flow rate control device capable of operating in two different modes: critical expansion mode (using only upstream pressure sensor) and non-critical expansion mode (using both upstream and downstream pressure sensors). The system automatically selects the appropriate measurement method based on the pressure ratio condition, allowing the device to maintain measurement precision across varying operating conditions while avoiding unnecessary complexity in each specific mode.
2Measurement precision
If pressure sensors are provided on both upstream and downstream sides, then the measurement precision of flow rate is improved, but the device complexity increases
Solution Approach 1:
The patent applies dynamics by implementing a dynamic selection mechanism that adapts the measurement system configuration based on real-time operating conditions. The control unit dynamically determines whether to use the upstream pressure sensor alone or both upstream and downstream pressure sensors, depending on whether the critical expansion condition (P1/P2 ≥ 2) is satisfied. This dynamic adaptation allows the system to maintain high measurement precision while minimizing device complexity for each specific operating scenario.
3Manufacturing precision
If the critical expansion condition is satisfied, then the flow rate control accuracy is improved, but the adaptability to different pressure conditions deteriorates
Solution Approach 1:
The patent applies parameter changes by switching between different measurement parameters based on the operating condition. When the critical expansion condition is satisfied (P1/P2 ≥ 2), the system uses only the upstream pressure parameter P1 for flow rate calculation. When the condition is not satisfied, the system changes to use both pressure parameters P1 and P2. This parameter switching enables the system to maintain high flow rate control accuracy across a wide range of pressure conditions, effectively resolving the contradiction between accuracy and adaptability.
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 allows for accurate and straightforward detection of abnormalities in valves and restriction portions, ensuring stable flow rate control by identifying changes in pressure and time differences, thereby preventing clogging or shape changes in the micro opening.
Implementation Method 1
a piezo element-driven pressure control valve
Implementation Method 2
the flow speed of the gas passing through the restriction portion is fixed to the speed of sound and the flow rate is determined not by a gas pressure P2 on the downstream side but by the gas pressure P1 on the upstream side when satisfying the following critical expansion condition
Data Source
AI summary
An abnormality detection method performed using a flow rate control device including a restriction portion, a control valve, a first pressure sensor, a second pressure sensor, and a downstream valve, includes a step of changing the control valve and the downstream valve from an open state to a closed state, a step of measuring an upstream pressure or a downstream pressure in the closed state, and at least one step of (a) extracting an upstream pressure at a point when a difference between the upstream pressure and the downstream pressure reaches a predetermined value as an upstream convergence pressure, and extracting the downstream pressure as a downstream convergence pressure, and (b) extracting the time from a point when the control valve are changed to a closed state to a point when a difference between the upstream pressure and the downstream pressure reaches a predetermined value as a convergence time.