Fluid Controller Stem Movement Limiting for Flow Precision
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Solution Overview
Problem
Existing fluid controllers used in semiconductor manufacturing face challenges in precise flow rate adjustment due to individual differences in valve Cv values, which can compromise durability if adjustments are not carefully managed.
Innovation Solution
A fluid controller with a stem vertical-movement-amount upper-limit-value setting means and a fine-adjustment mechanism that allows for precise adjustment of the stem's vertical movement within a predetermined range, ensuring durability while allowing for precise flow rate adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the stem vertical movement amount is adjusted to achieve precise flow rate adjustment (Cv value), then the flow rate precision is improved, but the durability of the diaphragm may be compromised if the movement amount exceeds the upper limit
Solution Approach 1:
The patent applies preliminary action by setting the upper limit value of the stem vertical movement amount in advance before operation. The upper limit value setting means pre-establishes the maximum safe movement distance that ensures diaphragm durability, preventing operators from inadvertently exceeding this limit during flow rate adjustments. This pre-set constraint allows precise Cv value adjustment while inherently protecting against durability-compromising movements.
2Measurement precision
If individual adjustment is performed for each valve to account for individual differences in Cv values, then the flow rate precision is improved, but the complexity of the adjustment process increases
Solution Approach 1:
The patent applies parameter changes by introducing a dedicated adjustment parameter (stem vertical movement amount) that directly controls the valve opening degree. The fine adjustment means enables precise modification of this parameter, while the upper limit value setting means establishes a safe boundary. This parameter-based approach simplifies individual adjustment for each valve by providing a direct, controllable mechanism that accounts for individual valve characteristics without requiring complex procedures.
3Adaptability or versatility
If the stem vertical movement amount is increased to compensate for individual differences among valves, then the adaptability to different valves is improved, but the durability is reduced due to excessive movement
Solution Approach 1:
The patent applies dynamics by making the stem vertical movement amount adjustable rather than fixed. The fine adjustment means allows the movement amount to be dynamically optimized for each individual valve based on its specific characteristics, while the upper limit value setting means ensures this dynamic adjustment remains within safe boundaries. This dynamic approach enables adaptability to individual valve differences while preventing excessive movement that would reduce diaphragm service life.
Data Source
AI summary
Provided is a fluid controller which enables precise flow-rate adjustment while securing the durability. The fluid controller includes a stem vertical-movement-amount upper-limit-value setting means 10 which sets an upper limit value of a vertical movement amount of a stem 8 associated with opening and closing operations. The fluid controller further includes a stem vertical-movement-amount fine-adjustment means 11 which changes the vertical movement amount of the stem 8 associated with the opening and closing operations, within a range of not greater than the upper limit value.