Piezoelectric Flow Valve Control for Pulse and Continuous Dosing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional flow rate control devices struggle to perform both pulse flow rate control and continuous flow rate control effectively, particularly in applications like Atomic Layer Deposition, where high-speed flow switching is required, and they often compromise on accuracy and cost due to the need for responsive solenoid valves.
Innovation Solution
A flow rate control device incorporating a pressure control valve, a flow rate control valve with a piezoelectric element and strain sensor, and a restriction part with a fixed opening degree, allowing for responsive control by adjusting the pressure control valve based on pressure sensor outputs and strain sensor feedback to manage both continuous and intermittent flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a solenoid valve is used to achieve high-speed flow switching for pulse flow rate control, then responsiveness is improved, but manufacturing cost increases and the simplicity advantage of pressure-type flow rate control devices is lost
Solution Approach 1:
The invention transforms the static restriction part into a dynamic valve element that can change its opening degree. The valve element is driven by a piezoelectric element, which converts electrical signals into mechanical displacement, enabling dynamic control of the flow passage area. This allows the system to achieve high-speed flow switching comparable to solenoid valves while maintaining the pressure-type control mechanism's cost-effectiveness and simplicity.
Solution Approach 2:
The invention replaces the electromagnetic actuation mechanism of solenoid valves with a piezoelectric actuation system. The piezoelectric element directly converts electrical voltage into mechanical displacement of the valve element, eliminating the need for electromagnetic coils and complex mechanical linkages. This substitution maintains fast response characteristics while reducing manufacturing cost and preserving the simplicity of the pressure-type control approach.
2Device complexity
If conventional pressure control method is used for pulse flow rate control, then device simplicity is maintained, but sufficient flow rate rise-up/fall-down characteristics cannot be obtained
Solution Approach 1:
The invention divides the flow control function into two distinct components: a pressure control valve for maintaining upstream pressure and a flow rate control valve with a variable restriction for controlling flow rate. By segmenting the control functions, the system can independently optimize pressure stability and flow switching speed, achieving both device simplicity and excellent flow rate rise-up/fall-down characteristics.
Solution Approach 2:
The invention implements feedback control by measuring the actual flow rate and comparing it with the target flow rate, then adjusting the valve element's opening degree accordingly. This closed-loop control ensures that the flow rate accurately follows the desired trajectory during pulse control, providing sufficient rise-up and fall-down characteristics while maintaining the simplicity of the pressure-type control mechanism.
3Manufacturing precision
If piezoelectric element driven valve is controlled with analogical slight displacement for continuous flow control, then flow rate control accuracy is maintained, but responsiveness for pulse control is insufficient
Solution Approach 1:
The invention enables the piezoelectric element to operate in two distinct dynamic modes: small-displacement analog mode for continuous flow control and large-displacement digital mode for pulse control. The control system dynamically selects the appropriate operation mode based on the control signal type, allowing the system to maintain flow rate control accuracy during continuous operation while achieving fast responsiveness during pulse switching.
Solution Approach 2:
The invention changes the operating parameters of the piezoelectric element based on the control mode. For continuous flow control, the piezoelectric element operates with small voltage changes producing slight displacements for precise analog control. For pulse control, the system applies large voltage steps that produce significant displacement for rapid opening and closing. This parameter adaptation allows the system to excel at both accuracy and responsiveness.
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 solution provides a flow rate control device with improved responsiveness and accuracy, capable of handling both pulse and continuous flow rate control while maintaining the cost-effectiveness and precision of pressure-type flow rate control devices.
Implementation Method 1
a piezoelectric element for moving the valve element so as to be seated on/separated from the valve seat
Implementation Method 2
a strain sensor that is installed on a side surface of the piezoelectric element
Data Source
AI summary
A flow rate control device (100) comprises: a pressure control valve (6) provided in a flow path; a flow rate control valve (8) provided downstream side of the pressure control valve; and a first pressure sensor (3) for measuring pressure on the downstream side of the pressure control valve and on the upstream side of the flow rate control valve. The flow rate control valve has a valve element (13) seated on/separated from a valve seat (12); a piezoelectric element (10b) for moving the valve element so as be seated on/separated from the valve seat; and a strain sensor (20) provided on a side surface of the piezoelectric element. The pressure control valve (6) is configured to control the pressure control valve (6) on the basis of a signal output from the first pressure sensor (3), and to control the driving of the piezoelectric element of the flow rate control valve (8) based on a signal output from the strain sensor (20).