Flow Sensor Sealing Lip Design for Laminar Flow
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Solution Overview
Problem
Existing flow sensors face challenges in achieving perfect sealing of the measuring channel, leading to dirt accumulation and turbulent flow, which impairs the accuracy of fluid flow measurements.
Innovation Solution
A flow sensor design featuring a base body with a flow channel and a cover plate, where a sealing lip circumferentially delimits the flow channel on the base body's upper side, pressed against the cover plate to form a sealed flow channel, preventing dirt accumulation and ensuring laminar flow by using a two-component injection molding process with different material areas for enhanced elasticity and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing ring is used to seal the measuring channel against the gap between housing parts, then sealing is improved, but the measuring channel is still not sealed against the gap between housing parts and adhesive can penetrate into the channel
Solution Approach 1:
The sealing function is extracted from the gap-sealing approach and relocated to the channel wall itself through the sealing lip that protrudes into the measuring channel, sealing the channel against the cover plate rather than trying to seal the gap between housing parts
Solution Approach 2:
The sealing lip acts as an intermediary element between the base body and the cover plate, creating a sealed barrier within the measuring channel that prevents adhesive and contaminants from entering while maintaining the necessary gap sealing
2Reliability
If two housing parts are bonded directly together to seal the measuring channel, then sealing is improved, but adhesive penetrates into the measuring channel causing contaminant accumulation
Solution Approach 1:
The base body is segmented into different material areas with distinct properties - a first material area forming the channel wall with sealing lip and a second material area providing structural support, allowing each segment to fulfill its specific function without compromising the other
Solution Approach 2:
Different material properties are assigned to different locations: the first material area has specific elastic properties optimized for sealing against the cover plate, while the second material area provides structural strength, creating local quality optimization throughout the base body
3Ease of manufacture
If the measuring channel is sealed by the gap between housing parts, then manufacturing is simplified, but dirt particles accumulate and flow becomes turbulent impairing measurement accuracy
Solution Approach 1:
The sealing lip made of elastic material acts as a flexible sealing element that can deform to ensure tight sealing against the cover plate, preventing contaminant ingress while maintaining smooth channel walls for laminar flow
Solution Approach 2:
The sealing lip is designed with elastic properties allowing it to dynamically adapt to manufacturing tolerances and assembly variations, ensuring consistent sealing performance and smooth flow conditions under different operating conditions
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
The design effectively reduces susceptibility to contamination, prevents adhesive penetration, and maintains a laminar flow, enhancing the accuracy and reliability of fluid flow measurements.
Implementation Method 1
The flow channel is formed in a significantly more elastic first material area than in the second material area, so that the flow channel is sealed against the cover plate by an elastic sealing lip that is integrally formed with the channel bed
Data Source
Figure 1~2
Figure 3a~3d
Figure 4a~4b
AI summary
In a flow sensor (1) comprising a flow channel (14) embedded in a base body (1'), a flow sensor element (13) adjacent to the flow channel (14) and a cover plate (12) covering the flow channel (14) and arranged on the base body (1'), the flow channel (14) is formed by an elastic sealing lip which delimits said channel (14), running on and around an upper side of the base body (1') lying opposite the cover plate (12) and is pressed against the cover plate (12) such that a seal is formed. The design of the flow channel (14) by means of the sealing lip (5) allows the flow channel (14) to be sealed off from possible gaps between the base body (1') and the cover plate (12) and in relation to the cover plate (12), such that a flow channel with a level channel bed (14) is formed by the sealing lip (15) and the cover plate (12) which channel bed has smooth peripheral areas and a uniform cross-section, and which if possible avoids the depositing and collection of dirt particles and thus prevents undesirable turbulence in the flow channel (14) and guarantees a laminar current through the flow channel (14).