Flow Rate Valve Feedback for Accurate Pulsed Gas Supply
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Solution Overview
Problem
Conventional flow rate control devices, particularly those using piezoelectric element-driven valves, struggle with high-speed pulse-shaped flow rate control due to limitations in response speed and variability in responsivity, leading to deviations between set and actual flow rates during pulsed operations.
Innovation Solution
A flow rate control device and method that includes a control valve, a flow rate measurement unit, and a controller. The controller calculates and compares measurement integral flow rates with target integral flow rates, initiating valve closure when the difference falls within a predetermined range, ensuring accurate gas supply even during pulsed operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a piezoelectric element-driven valve is used to control flow rate, then the valve can be opened and closed by controlling applied voltage, but the response speed of opening/closing is limited and cannot achieve high-speed pulse-shaped flow rate control
Solution Approach 1:
The patent replaces the piezoelectric element-driven valve with a valve driven by a solenoid actuator. This mechanical substitution enables faster response speeds suitable for high-speed pulse-shaped flow rate control while maintaining adequate control accuracy through feedback mechanisms.
Solution Approach 2:
The patent implements feedback control by measuring the actual flow rate with a flow rate measurement unit and comparing it with the set flow rate. The controller adjusts the valve operation based on the deviation between measured and target flow rates, ensuring accurate flow rate control even with faster-responding valves.
2Loss of time
If the valve opening/closing speed is increased for pulse flow rate control, then the response time is reduced, but deviation between set flow rate and actual flow rate increases
Solution Approach 1:
The patent uses feedback control where the flow rate measurement unit continuously monitors the actual flow rate and the controller adjusts the valve operation based on the deviation from the set flow rate. This closed-loop control ensures accurate flow rate control despite faster valve response times.
Solution Approach 2:
The patent dynamically adjusts the valve operation based on real-time flow rate measurements. The controller modifies the valve opening/closing characteristics during operation to maintain accuracy, rather than using fixed valve response characteristics.
3Ease of operation
If conventional flow rate control methods are used, then the system is simple to operate, but the responsivity of the control valve varies from device to device and stable pulse flow rate control cannot be performed
Solution Approach 1:
The patent implements feedback control that automatically compensates for device-to-device variations in valve responsivity. The flow rate measurement unit measures the actual flow rate, and the controller adjusts the valve operation based on the deviation from the target, eliminating the need for manual calibration and ensuring consistent performance across different devices.
Solution Approach 2:
The system performs self-calibration and self-adjustment through the feedback mechanism. Each device automatically adapts to its specific characteristics during operation, with the controller learning and compensating for individual device variations without external intervention.
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 precise and stable pulsed flow rate control, ensuring appropriate gas supply by matching measurement integral flow rates with target integral flow rates, regardless of device variability, thus addressing the limitations of conventional systems.
Implementation Method 1
a piezoelectric element-driven valve for opening/closing a diaphragm valve element by a piezo actuator
Data Source
AI summary
A flow rate control device 100 includes a control valve 6 provided in a flow path 1, a flow rate measurement unit 2, 3 for measuring fluid flow rate controlled by the control valve 6, and a controller 7. The controller 7 is configured so as to control the opening/closing operation of the control valve 6 to match the measurement integral flow rate based on the signal outputted from the flow rate measurement unit (Vn+Vd) to the target integral flow rate Vs.