Flow Rate Control Apparatus with Parallel Orifices for Wide Range Accuracy
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Solution Overview
Problem
Conventional flow rate control apparatuses face challenges in maintaining high accuracy over a wide flow rate range, leading to increased manufacturing costs and complexity due to the need for multiple apparatuses with different flow rate ranges, and the pressure type flow rate control apparatus experiences a reduced control range with rising orifice secondary side pressure, causing unevenness in semiconductor product quality.
Innovation Solution
A flow rate range variable type control apparatus that switches fluid passages and detection levels for small and large flow quantities, using multiple orifices in parallel with switching valves to achieve accurate flow rate control across a wide range, and incorporates thermal type mass flow rate control elements with laminar flow elements and switching valves to manage different flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple flow rate control apparatuses with different flow rate ranges are provided in parallel, then high flow rate control accuracy can be maintained over a wide flow rate control range, but installation costs go up and the system becomes more complex
Solution Approach 1:
The flow rate control apparatus is segmented into multiple flow rate areas (large flow quantity area, medium flow quantity area, small flow quantity area) with dedicated control valves for each area. This segmentation allows each valve to be optimized for its specific flow range, maintaining high control accuracy across the entire wide range without requiring multiple complete apparatuses in parallel.
Solution Approach 2:
A single flow rate control apparatus is designed to handle multiple flow rate ranges by incorporating multiple control valves that can be selectively activated based on the required flow rate. This multi-functionality eliminates the need for separate apparatuses for different flow ranges, reducing system complexity while maintaining accuracy.
2Measurement precision
If multiple flow rate control apparatuses with different flow rate ranges are provided in parallel, then high flow rate control accuracy can be maintained over a wide flow rate control range, but installation costs go up
Solution Approach 1:
Multiple control valves for different flow rate areas are merged into a single integrated flow rate control apparatus. This combination allows the system to achieve the accuracy benefits of multiple specialized apparatuses while incurring only the cost of one apparatus, significantly reducing installation costs.
Solution Approach 2:
The apparatus is designed with universal capability to handle multiple flow rate ranges through selective activation of different control valves, eliminating the need to purchase and install multiple separate apparatuses, thereby reducing installation costs.
3Adaptability or versatility
If the flow rate control range is expanded, then a wider range of flow rates can be controlled, but control accuracy is lowered in low flow rate situations
Solution Approach 1:
The flow rate control range is segmented into multiple areas (large, medium, small flow quantity areas), each with its own optimized control valve. This segmentation ensures that low flow rate control accuracy is maintained by using a control valve specifically optimized for the small flow quantity area, rather than relying on a single valve designed for the entire range.
Solution Approach 2:
Each control valve is designed with local quality optimized for its specific flow rate area. The control characteristics, valve geometry, and detection sensitivity are tailored to the specific requirements of each flow range, ensuring high accuracy in low flow rate situations while maintaining the ability to control a wide overall range.
4Device complexity
If a pressure type flow rate control apparatus is used, then simplicity of structure and responsiveness are improved, but the control range is reduced with rising orifice secondary side pressure
Solution Approach 1:
The pressure type flow rate control apparatus is segmented into multiple flow rate areas with different control valves. This segmentation compensates for the reduced control range of the pressure type design by providing multiple valves that collectively cover a wide flow rate range, maintaining structure simplicity while expanding adaptability.
Solution Approach 2:
The apparatus dynamically selects which control valve to use based on the required flow rate and orifice secondary side pressure conditions. This dynamic adaptation allows the system to maintain the structural simplicity and responsiveness of pressure type control while achieving a wide effective control range through selective valve activation.
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
Enables highly accurate flow rate control with less than 1% error across a wide range, simplifies operations by automatic range selection, and reduces manufacturing costs by using a single apparatus for various flow rates, while maintaining excellent control under critical conditions.
Implementation Method 1
a laminar flow element device part; a flow rate sensor part
Data Source
AI summary
A pressure type flow rate control apparatus is provided wherein flow rate of fluid passing through an orifice is computed as Qc=KP1 (where K is a proportionality constant) or as Qc=KP2m (P1-P2)n (where K is a proportionality constant, m and n constants) by using orifice upstream side pressure P1 and/or orifice downstream side pressure P2. A fluid passage between the downstream side of a control valve and a fluid supply pipe of the pressure type flow rate control apparatus comprises at least 2 fluid passages in parallel, and orifices having different flow rate characteristics are provided for each of these fluid passages, wherein fluid in a small flow quantity area flows to one orifice for flow control of fluid in the small flow quantity area, while fluid in a large flow quantity area flows to the other orifice for flow control of fluid in the large flow quantity area.