Convex Membrane for Pressure Dome Air Infiltration
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Solution Overview
Problem
Existing pressure domes for measuring pressure in extra-corporeal circuits face issues such as air infiltration between the membrane and sensor, loss of flatness due to elastomer ageing, and complex manufacturing processes, leading to inaccurate measurements and increased production costs.
Innovation Solution
A pressure dome with a resilient, convex membrane made from a single material, featuring a circular rim for stable fixation and a beading mechanism for assembly, which minimizes air pockets and maintains functionality even with elastomer relaxation, and can be produced using simpler manufacturing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat elastomer membrane is used in the pressure dome, then the manufacturing process is simple, but air pockets form between the membrane and sensor during assembly and measurement
Solution Approach 1:
The patent applies curvature to the membrane surface, specifically designing it with a convex outwardly curved shape rather than a flat surface. This curvature prevents air pockets from forming between the membrane and sensor during assembly, as the curved surface naturally guides air outward during the bonding process, eliminating the reliability issue while maintaining manufacturing simplicity
2Measurement precision
If the elastomer membrane is made highly resilient to transmit pressure variations, then pressure measurement sensitivity is improved, but the membrane loses flatness over time due to ageing
Solution Approach 1:
The patent designs the membrane with an inherently convex curved shape from the outset, rather than relying on it to remain flat. This initial curvature compensates for the natural tendency of resilient elastomers to lose flatness during aging, ensuring that the membrane maintains its functional shape and measurement accuracy throughout its service life
Solution Approach 2:
The patent changes the geometric parameter of the membrane from flat to convex curved. This parameter change fundamentally alters how the membrane behaves under stress and aging, transforming the aging effect from a detrimental loss of flatness into a manageable characteristic that maintains functional performance
3Productivity
If a two-component injection molding process is used to manufacture the pressure dome, then the elastomer membrane and fixing ring are produced in a single operation, but the manufacturing complexity and initial outlay increase
Solution Approach 1:
The patent divides the manufacturing process into separate operations: first producing the elastomer membrane through injection molding, then separately producing the fixing ring and main body, and finally assembling them together. This segmentation simplifies the molding processes themselves while maintaining productivity through efficient separate production and assembly
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 convex membrane design effectively transmits pressure while reducing air infiltration and maintaining accuracy over time, and simplifies the manufacturing process, ensuring reliable and efficient pressure measurement without the need for preassembly of components.
Implementation Method 1
The elastomer membrane is highly resilient so that it is able to transmit to the sensor the pressure present inside the circuit and the associated variations
Data Source
Figure 1
Figure 2
Figure 3.a~3.b
AI summary
The present invention relates to a membrane (12) for a pressure dome (10) suitable for cooperation with a pressure sensor (22). The membrane comprises a resilient circular Avail (120) suitable for closing one side of the pressure dome (10) so as to define a partition between the inside of the pressure dome and the outside; and a circular rim (124) suitable for being joined to a main body (16) of the pressure dome. The membrane is characterized in that the resilient circular wall, when there is no difference between the pressures acting respectively on the inner surface (121) and on the outer surface (122), has an outwardly convex form. The invention also relates to a pressure dome comprising the membrane.