Flow Sensor Bypass Taps Laminar Flow Element
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Solution Overview
Problem
Existing flow sensors with bypass taps placed upstream and downstream of a laminar flow element face issues such as increased signal noise due to turbulence, unstable flow, and non-linear output in lower flow ranges, primarily due to the perpendicular orientation of taps in a turbulent flow zone and non-linear orifice effects.
Innovation Solution
The design includes a flow sensor with a main flow body, a laminar flow element, and bypass taps with a larger cross-sectional area than the bypass flow channel, positioned between the ends of the laminar flow element to reduce turbulence and noise, and a longer bypass flow channel to minimize orifice effects, ensuring more laminar flow and stable pressure measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bypass taps are placed upstream and downstream of the laminar flow element, then a large flow volume is available for redirection into the bypass flow channel, but the taps are placed in a turbulent flow zone which increases signal noise
Solution Approach 1:
The patent introduces an intermediary laminar flow element between the main flow channel and the bypass taps. This intermediary component transforms the turbulent flow into laminar flow, allowing the bypass taps to access sufficient flow volume while operating in a laminar zone that does not generate signal noise.
2Quantity of substance
If bypass taps are placed upstream and downstream of the laminar flow element, then flow volume is available for bypass, but flow agitation from turbulence and unstable flow at LFE inlet/outlet adversely affect sensor signal
Solution Approach 1:
The laminar flow element acts as a mediator that stabilizes the flow conditions. By positioning the bypass taps within or downstream of the LFE, the system ensures that only stable, laminarized flow reaches the bypass channel, eliminating the adverse effects of turbulence and flow agitation on sensor signal reliability.
3Productivity
If flow is restricted through the bypass channel using orifices or small diameter features, then bypass flow rate is controlled, but non-linear orifice effects create non-linear output and reduce signal in lower flow ranges
Solution Approach 1:
The patent changes the critical parameter from orifice diameter to bypass channel length to control flow rate. By making the bypass channel sufficiently long, flow restriction is achieved through viscous effects in a laminar flow regime rather than through orifice effects, maintaining linearity across the full flow range including lower flow rates.
4Measurement precision
If a long bypass flow channel is used to reduce orifice effects, then non-linear output is reduced, but the device complexity and size increase
Solution Approach 1:
The patent nests the bypass flow channel within or alongside the laminar flow element structure. This nested arrangement allows the bypass channel to achieve the necessary length for linear flow characteristics while utilizing the existing structural space, thereby reducing overall device complexity and size compared to a separate, extended bypass channel design.
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 signal noise, stabilizes flow, and improves accuracy by maintaining laminar flow conditions, enhancing sensitivity and response time, particularly in high flow rate measurements.
Implementation Method 1
A laminar flow element (LFE) may be incorporated in the main flow channel. A typical LFE may include multiple parallel flow channels with relatively small cross-sectional area to laminarize the main flow and create a pressure restriction.
Implementation Method 2
The perpendicular orientation of the taps presents static pressure at the taps. The difference in the static pressure between the first and second taps drives flow through the bypass flow channel.
Data Source
AI summary
A flow sensor includes a main flow body, a laminar flow element, a first bypass tap, and a second flow element sensor tap. The main flow body has a first main flow port, a second main flow port, a main flow channel, a first bypass tap, a second bypass tap, and a bypass flow channel. The laminar flow element is disposed within the main flow channel. The bypass flow channel has a cross sectional area, and the first bypass tap and the second bypass tap each have a cross sectional area that is greater than the maximum cross sectional area of the bypass flow channel.