Variable Orifice Flow Sensor With Localized Biasing
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Solution Overview
Problem
The performance of variable orifice flow sensors is compromised by the rigid or loose connection of the bending member to the housing, leading to distorted flapper movement, leaks, and inaccurate flow rate measurements due to altered pressure differences.
Innovation Solution
A variable orifice fluid flow sensor design featuring two port portions with a biasing member that engages the bending member with constant contact elements, preventing distortion and leaks, and allowing for precise measurement of fluid flow rates without direct securing to the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the bending member is rigidly secured to the housing, then the connection strength is improved, but the flapper movement becomes distorted and measurement accuracy deteriorates
Solution Approach 1:
A biasing member with biasing elements is introduced as an intermediary between the bending member and the housing. This mediator provides localized contact forces that secure the bending member in position while allowing it to flex and move freely in response to fluid flow, thus maintaining both connection strength and measurement accuracy
Solution Approach 2:
The biasing elements provide localized contact forces at specific points on the bending member rather than rigid uniform support. This localized engagement allows the bending member to maintain stable positioning while preserving its ability to deflect naturally with fluid flow, preventing distortion of flapper movement
2Ease of operation
If the bending member is loosely secured to the housing, then the flapper movement freedom is improved, but fluid leaks occur and measurement reliability deteriorates
Solution Approach 1:
The biasing member acts as an intermediary that provides just enough contact force to prevent fluid leaks between the bending member and housing, while not restraining the flapper's movement freedom. The localized biasing elements maintain sealing contact without over-constraining the bending member
Solution Approach 2:
The biasing elements can be designed with adjustable parameters such as contact force magnitude and contact point locations. By optimizing these parameters, the system achieves the right balance between preventing leaks (maintaining reliability) and allowing sufficient flapper movement freedom
3Reliability
If tight engagement between bending member and housing is used, then sealing is improved, but low flow resolution and linearity deteriorate
Solution Approach 1:
The biasing elements provide sealing contact only at specific localized points on the bending member rather than along the entire interface. This localized sealing approach maintains adequate sealing performance while minimizing interference with the bending member's natural deflection and flapper movement, preserving low flow resolution and linearity
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 design ensures accurate and reproducible measurement of fluid flow rates across a broad range by maintaining the flapper's operation and preventing leaks, even with looser assembly tolerances, thereby improving low flow resolution and linearity.
Implementation Method 1
The biasing member includes a number of biasing elements that extend outwardly from the biasing member into contact with the bending member. The engagement of the biasing elements with the bending member provides a constant contact and/or biasing force against the bending member
Implementation Method 2
The bending member is mounted to the housing for the fluid flow passage and includes a flapper that is positioned across the fluid flow passage and bends or flexes in the direction of the fluid flow as a result of contact with the fluid flow
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A variable orifice fluid flow sensor is provided that includes a fluid flow passage therethrough formed with a first port portion adjacent to one end of said passage and a second port portion adjacent to the other end of said passage. A bending member is mounted in the fluid flow passage between the first and second port portions and having a fluid flow limiting flapper extending across the fluid flow passage for creating a fluid flow opening in the passage, the size of the opening being variable responsive to fluid flow in said fluid flow passage. A biasing member is also mounted between the first and second port portions and includes at least one biasing element extending away from the biasing member into contact with the bending member to exert a contact force on the bending member.