Diaphragm Valve Support Structure for Stable High Gas Flow
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Solution Overview
Problem
Diaphragm valves in mass flow controllers face challenges in achieving high flow rates for gases with low equilibrium vapor pressure, as increasing pressure difference leads to diaphragm deformation, reducing the gap distance and flow rate, especially when handling precursors like organic metallic compounds and metal halides in semiconductor manufacturing.
Innovation Solution
A diaphragm valve design with a tubular valve seat and a supporting member that contacts the diaphragm between the seating center and surface, preventing deformation and maintaining a larger gap distance, even under high pressure differences, to ensure stable high flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure difference between primary side and secondary side is increased to increase flow rate, then flow rate increases, but diaphragm deforms toward secondary side passage reducing gap distance and flow rate
Solution Approach 1:
The supporting member is positioned to preemptively counteract the diaphragm's deformation toward the secondary side passage before it occurs. By providing preliminary support at the location where deformation would most affect the gap distance, the system maintains stable flow characteristics even under high pressure differences.
Solution Approach 2:
The supporting member acts as an intermediary element between the diaphragm and the secondary side passage. It provides mechanical support to the diaphragm, preventing excessive deformation while allowing controlled movement for valve operation, thus mediating between the conflicting requirements of high flow rate and stable gap distance.
2Productivity
If seating surface is extended to periphery of diaphragm to increase maximum flow rate, then peripheral length of seating surface increases, but diaphragm deformation becomes more pronounced under pressure difference
Solution Approach 1:
The supporting member is strategically positioned to counteract deformation at the most critical location before it propagates. By placing support between the seating center and seating surface, the system prevents the diaphragm from deforming excessively, even with the extended seating surface configuration that enables higher flow rates.
Solution Approach 2:
The supporting member provides localized support at a specific region between the seating center and seating surface, rather than uniformly supporting the entire diaphragm. This local quality approach allows the diaphragm to maintain its sealing function at the seating surface while preventing deformation in the critical intermediate region.
3Measurement precision
If piezo-electric element is used for driving mechanism, then precise control is achieved, but motion range is limited to at most 50 micrometers making it difficult to extend distance d
Solution Approach 1:
The invention addresses the limited motion range in one dimension (vertical displacement of pressing member) by introducing a spatial dimension (radial positioning of supporting member). The supporting member's position between the seating center and seating surface creates a geometric lever arm that amplifies the effect of limited pressing member displacement, effectively extending the functional gap distance without requiring larger piezo-electric element travel.
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
This configuration reduces fluid resistance and maintains high flow rates for gases with low equilibrium vapor pressure, preventing diaphragm deformation and ensuring stable gas supply to semiconductor equipment.
Implementation Method 1
even when a pressure difference between both sides of a diaphragm is large, a decrease in the distance of a gap of the diaphragm valve can be suppressed. Therefore, by using the mass flow controller which comprises the present invention valve, a gas having a low equilibrium vapor pressure can be stably supplied to semiconductor manufacturing equipment, etc., at a large flow rate.
Data Source
AI summary
In a diaphragm valve comprising a tubular valve seat, a primary side passage located outside the valve seat, a secondary side passage located inside the valve seat, and pressing member which presses the diaphragm to a seating surface to change a valve opening, a supporting member which contacts with the diaphragm in a valve opening range that is at least one part of an entire opening range from a fully opened state to a fully closed state to obstruct deformation of the diaphragm to the secondary side passage side is disposed in a region between the seating surface and a center of the seating surface. Thereby, even when a pressure difference between both sides of the diaphragm is large, a reduction of a gap at the seating surface can be prevented, and gas can be flowed at a large flow rate.