Dual-Actuator Fluid Valve Control for Stable High-Flow Supply
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Solution Overview
Problem
Existing fluid control devices struggle to stably supply fluids at large flow rates, especially when primary side fluid pressure fluctuations occur, as they often rely on piezoelectric element driven valves that have limitations in valve opening range and are prone to flow restriction.
Innovation Solution
A fluid control device comprising a valve device with a main actuator for opening/closing and a sub-actuator for fine adjustment, coupled with a pressure sensor and control circuit that adjusts the actuator operation based on measured pressure and a reference pressure drop curve, allowing stable fluid supply even with primary side pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezoelectric element driven valve is used for flow rate control, then high responsivity and accurate flow rate control are achieved, but the valve opening range is limited and large flow rate supply becomes difficult
Solution Approach 1:
The valve device is divided into two independent valves: a first valve (piezoelectric element driven) for precise flow rate control at small openings, and a second valve (pneumatic element driven) for large opening operations. This segmentation allows each valve to specialize in its optimal operating range, resolving the contradiction between precision control and wide opening range.
Solution Approach 2:
The patent combines two different valve mechanisms (piezoelectric-driven valve and pneumatic-driven valve) into a single integrated valve device. The piezoelectric valve handles fine control while the pneumatic valve provides large opening capability, merging the advantages of both actuation methods to achieve both precision and wide range.
2Measurement precision
If gas is supplied through a restriction part for flow rate control, then stable flow rate control is achieved, but the gas flow is always restricted and large flow rate supply becomes difficult
Solution Approach 1:
The system dynamically switches between two flow paths: one through the restriction part (orifice plate) for stable controlled flow at lower rates, and another through the large-opening second valve for high flow rate supply. This dynamic configuration allows the system to maintain stability when needed while achieving high productivity when required.
Solution Approach 2:
The valve device is designed with multi-functionality to handle both restricted flow control and unrestricted high flow rate supply. By incorporating both a restriction-based control path and a valve-based control path, the system can adapt to different flow rate requirements without being limited to a single mode of operation.
3Reliability
If pressure type flow rate control device is used with control valve, then stable flow rate control is achieved even with primary side pressure fluctuations, but the device complexity increases
Solution Approach 1:
The control circuit continuously monitors the upstream pressure and adjusts the opening degree of the first valve based on feedback from pressure sensors. This closed-loop feedback control maintains stable flow rate control despite primary side pressure fluctuations, achieving high reliability through active compensation.
Solution Approach 2:
The first valve acts as an intermediary between the fluctuating primary side pressure and the process chamber. By positioning the valve upstream and using it to regulate pressure before the restriction part, the system isolates the downstream flow control from upstream pressure variations, simplifying the overall control mechanism.
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
The fluid control device effectively stabilizes fluid supply at large flow rates despite primary side pressure fluctuations, ensuring consistent operation by precisely controlling the valve opening degree based on real-time pressure measurements and reference curves.
Implementation Method 1
a pressure sensor provided upstream of the valve device
Implementation Method 2
a piezoelectric element driven valve (also referred to as a piezo valve) configured to open/close a metal diaphragm valve element by a piezoelectric element drive device
Data Source
AI summary
A fluid control device 10 comprises a valve device V2 including actuators 22 and 24 for opening and closing a flow path and adjusting a flow rate of a fluid flowing through the flow path, a pressure sensor PT provided upstream of the valve device V2, and a control circuit 12 connected to the valve device V2 and the pressure sensor PT, and the control circuit 12 controls an operation of the actuator based on a pressure measured by the pressure sensor PT and a reference pressure drop curve, while the upstream side of the fluid control device is closed and the valve device is opened using the actuators.