Orifice-Built-In Valve Synchronization in Pressure Flow Control
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Solution Overview
Problem
Pressure-type flow rate control devices with orifice-built-in valves face challenges in accurately detecting and controlling gas flow rates due to synchronization issues between the opening/closing signal and actual operation of air-operated valves, leading to incorrect flow rate calculations and delayed responses in fast gas switching applications like ALD and ALE processes.
Innovation Solution
A pressure-type flow rate control device is designed with an orifice-built-in valve, a pressure sensor downstream of the control valve, and an opening/closing-detection mechanism, such as a limit switch, to accurately detect the valve's state and control the flow rate based on signals from the pressure sensors and the detection mechanism, ensuring synchronized operation and real-time flow rate monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an air operated valve (AOV) is used as the valve mechanism of an orifice-built-in valve, then the opening/closing operation can be controlled by an electromagnetic valve, but the opening/closing signal and actual valve operation become unsynchronized due to delays in the compressed air supply system
Solution Approach 1:
The patent introduces a detection mechanism that provides real-time feedback on the actual opening/closing state of the orifice-built-in valve. This feedback signal is used by the control unit to synchronize the flow rate calculation with the actual valve state, eliminating the time loss caused by signal delays in the compressed air supply system.
Solution Approach 2:
The patent replaces reliance on mechanical signal transmission through the compressed air system with an electronic detection and feedback system. The detection mechanism directly senses the valve state and transmits this information electronically to the control unit, substituting the delayed mechanical response with immediate electronic feedback.
2Productivity
If the opening/closing state of the orifice-built-in valve is not accurately detected, then flow rate control accuracy deteriorates in fast gas switching applications like ALD and ALE processes
Solution Approach 1:
The detection mechanism provides real-time feedback on the actual valve opening/closing state, enabling the control unit to accurately calculate flow rates during fast gas switching operations. This feedback loop ensures that flow rate measurements remain precise even during rapid transitions in ALD and ALE processes.
Solution Approach 2:
The detection mechanism is positioned to detect the valve state before it affects the flow rate calculation, allowing the control unit to prepare and adjust measurements in advance. This preliminary detection ensures accurate flow rate measurement is ready when needed during fast switching operations.
3Adaptability or versatility
If compressed air supply to the AOV malfunctions, then the valve may not operate even when the electromagnetic valve is open, but this malfunction cannot be detected without an opening/closing-detection mechanism
Solution Approach 1:
The detection mechanism continuously monitors the actual valve opening/closing state and provides feedback to the control unit. When a malfunction occurs in the compressed air supply system, the detection mechanism identifies the discrepancy between the commanded and actual valve states, enabling the system to detect and respond to reliability issues.
Solution Approach 2:
The detection mechanism serves as a preventive measure that identifies potential failures before they affect process outcomes. By continuously monitoring valve operation, the system can detect malfunctions early and take corrective action, cushioning against the impact of compressed air supply failures.
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 device effectively controls and detects gas flow rates with improved accuracy and synchronization, preventing incorrect flow rate calculations and ensuring precise gas supply even during fast switching operations, thereby enhancing the reliability of pressure-type flow rate control in semiconductor manufacturing and chemical processing.
Implementation Method 1
a flow rate is determined by an upstream gas pressure P1 regardless of a downstream gas pressure P2 when the critical expansion condition P1/P2≥2 is satisfied
Implementation Method 2
a piezo element-driven control valve and a restriction part
Data Source
AI summary
A pressure-type flow rate control device includes a control valve; a pressure sensor provided downstream of the control valve; an orifice-built-in valve provided downstream of the pressure sensor; and a control unit connected to the control valve and pressure sensor. The built-in orifice valve has a valve mechanism comprising a valve seat body and a valve element for opening/closing a flow path; a drive mechanism for driving the valve mechanism, and an orifice member provided in the vicinity of the valve mechanism. The pressure-type flow rate control device further includes an opening/closing-detection mechanism for detecting the open/closed state of the valve mechanism, the control unit being configured to receive a detection signal from the opening/closing-detection mechanism.