Turning Vane for Mass Flow Controller Bypass Linearity
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Solution Overview
Problem
Mass flow controllers and meters face limitations in flow rate measurement accuracy due to bypass non-linearity, which degrades instrument range and turndown, particularly caused by entrance effects at the bypass inlet.
Innovation Solution
Incorporating a turning vane with a flow mixer upstream of the inlet mesh to redistribute fluid flow uniformly, enhancing bypass linearity and increasing turndown value by up to 15%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a flow bypass is used to achieve higher flow rates, then the maximum flow rate increases, but bypass non-linearity degrades instrument range and accuracy
Solution Approach 1:
The turning vane is positioned upstream of the bypass inlet to pre-condition the flow before it enters the bypass. This preliminary action redistributes the flow uniformly and reduces entrance effects, ensuring that the bypass maintains a constant flow ratio across the entire operating range, thereby improving bypass linearity while preserving the ability to measure high flow rates
2Adaptability or versatility
If the bypass ratio is increased to extend instrument range, then the turndown improves, but non-linearity increases and degrades accuracy
Solution Approach 1:
The turning vane performs preliminary flow redistribution upstream of the bypass inlet, ensuring uniform flow distribution before the bypass. This allows the instrument to achieve extended range and turndown while maintaining accurate bypass ratio measurement across all flow conditions, resolving the trade-off between range and accuracy
3Device complexity
If entrance effects at the bypass inlet are present, then the bypass design is simpler, but non-linearity increases and turndown decreases
Solution Approach 1:
The turning vane is added as a relatively simple upstream component that performs preliminary flow conditioning. This modest addition significantly reduces entrance effects and non-linearity, enabling the bypass design to achieve high turndown and extended instrument range without excessive complexity
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
Improves the accuracy and range of mass flow controllers and meters by maintaining a consistent flow ratio across varying rates, reducing bypass non-linearity and enhancing the overall performance of the instrument.
Implementation Method 1
Incorporating a turning vane with a flow mixer upstream of the inlet mesh to redistribute fluid flow uniformly
Implementation Method 2
Incorporating a turning vane with a flow mixer upstream of the inlet mesh to redistribute fluid flow uniformly
Data Source
Figure 1
Figure 1A~1B
Figure 2
AI summary
The disclosed embodiments include a mass flow controller for controlling a flow of a fluid. In one embodiment, the mass flow controller comprises an inlet for receiving the fluid; a flow path in which the fluid passes through the mass flow controller; a mass flow meter for providing a signal corresponding to mass flow of the fluid through the flow path, the mass flow meter having a bypass through which a majority of fluid flows; a turning vane positioned upstream of the bypass for generating a more uniform fluid flow; an adjustable valve for regulating the flow of the fluid out of an outlet of the mass flow controller; and a controller configured to apply a valve control signal to adjust the adjustable valve to a desired valve position to control the flow of the fluid out of an outlet of the mass flow controller.