Two-Stage Fluid Valve for Leak-Free Shut-Off and Precise Flow
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Solution Overview
Problem
Conventional MEMS microvalves experience fluid leakage during normal operation, making them unsuitable for use in gas ranges and ovens that require precise flame or temperature control and a positive shut-off function to prevent hazardous gas flow.
Innovation Solution
A two-stage fluid control valve is designed with a first stage electronically switchable, bi-stable two-port valve and a second stage microvalve, where the bi-stable two-port valve is movable between open and leak-free closed positions, ensuring precise control of fluid flow by using a sleeve, pole pieces with wire-wound coils, and a permanent magnet to manage the armature's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional MEMS microvalve is used to control fluid flow, then precise flow control is achieved, but fluid leakage occurs during normal operation
Solution Approach 1:
The valve system is divided into two independent stages: a first stage bi-stable two-port valve for positive shut-off and a second stage microvalve for precise flow control. Each stage performs its specialized function independently, with the first stage ensuring complete closure and the second stage providing modulation capability.
Solution Approach 2:
The first stage bi-stable two-port valve acts as an intermediary between the fluid source and the second stage microvalve. It provides a leak-free barrier that prevents hazardous gas flow while allowing the microvalve to control flow precisely when open.
2Volume of moving object
If a conventional microvalve is used, then the valve structure is compact, but it cannot provide a positive shut-off function
Solution Approach 1:
The valve function is segmented into two stages with different design priorities. The first stage is optimized for compact shut-off capability, while the second stage provides flow control. Together they achieve both compact size and positive shut-off function.
Solution Approach 2:
Two different valve technologies are merged into a single integrated system. The bi-stable two-port valve combines with the microvalve to create a unified device that leverages the strengths of both approaches for complete functionality.
3Reliability
If a bi-stable two-port valve is added as a first stage, then leak-free shut-off is achieved, but device complexity increases
Solution Approach 1:
The bi-stable two-port valve uses magnetic fields from coils to achieve stable positioning in open or closed states without requiring continuous power or complex control mechanisms. The system serves itself by maintaining state through magnetic stability rather than active control.
Solution Approach 2:
The complex continuous control function is extracted from the first stage and assigned to the second stage microvalve. The first stage only handles the binary open/closed shut-off function, simplifying its design while the microvalve manages the continuous flow control.
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 leak-free positive shut-off function and precise fluid flow control, addressing the leakage issues of conventional microvalves and meeting the requirements for gas range and oven applications.
Implementation Method 1
An electric current is applied to the first wire-wound coil to magnetize the first pole piece, thus causing the armature to move toward the first pole piece
Implementation Method 2
a permanent magnet defining an armature and movably mounted between the first and second pole pieces
Data Source
AI summary
A two-stage fluid control valve includes a first stage electronically switchable, bi-stable two-port valve movable between an open position and a leak-free closed position, and a second stage microvalve configured to control the flow of fluid through a fluid outlet of the two-stage fluid control valve when the first stage electronically switchable, bi-stable two-port valve is in the open position. The electronically switchable, bi-stable two-port valve is disposed between the second stage microvalve and a fluid inlet of the two-stage fluid control valve.