CPAP Exhaust Vent Membrane for Stable Bias Flow
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Solution Overview
Problem
Existing CPAP systems face challenges in maintaining a constant bias flow over a wide range of operating pressures, leading to noise and draft disturbances for patients and their bed partners, as well as increased power consumption and physical dimensions in the flow and humidity source.
Innovation Solution
The introduction of a bias flow control valve with a membrane that has concave and convex portions, allowing the flow path size to vary in response to pressure changes, helps regulate the bias flow more consistently across different pressure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed dimension hole/array is used for washout vent, then the structure is simple and easy to manufacture, but the bias flow increases as CPAP pressure level increases causing noise and draft disturbances
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed-dimension hole/array with a deformable membrane structure that dynamically adjusts its flow path area in response to pressure changes. The membrane deforms under varying CPAP pressures to maintain relatively constant bias flow, eliminating the noise and draft disturbances caused by fixed structures while remaining manufacturable through molding processes.
Solution Approach 2:
The patent applies parameter changes by modifying the physical state of the vent structure from rigid to flexible. The membrane's deformability allows the flow path area parameter to change dynamically with pressure, transforming the fixed parameter system into a variable parameter system that adapts to operating conditions and eliminates harmful noise and draft effects.
2Ease of manufacture
If fixed dimension holes are used for washout vent, then manufacturing is simple, but the bias flow rate increases with pressure leading to increased power consumption and physical dimensions of flow source
Solution Approach 1:
The dynamic membrane structure automatically regulates bias flow to remain relatively constant across varying CPAP pressures. This eliminates the need for the flow source to accommodate peak flow demands at high pressures, reducing the required physical dimension and power consumption of the flow source while maintaining simple manufacturing processes.
Solution Approach 2:
The membrane structure performs self-regulation of bias flow without external control mechanisms. It automatically adjusts its flow path area in response to pressure changes, eliminating the need for complex control systems and reducing the overall system's power consumption requirements while maintaining ease of manufacture.
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 solution reduces the variance in bias flow rate, minimizing noise and draft disturbances, and optimizing the flow source's size and energy requirements, thereby enhancing the overall performance and user experience of CPAP systems.
Implementation Method 1
The first end of the membrane has at least one concave portion and at least one convex portion and the first end of the membrane is configured to collapse inwardly to vary a flow path size in response to changes in pressure acting on the membrane
Data Source
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Figure 3
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AI summary
A valve (10) for use with a system for delivering CPAP therapy, the valve (10) comprising a base (12) and a membrane (14), the membrane (14) having a first end defining an inlet opening (18), the base (12) having a second end defining an outlet opening (16), the first end of the membrane (14) having at least one concave portion and at least one convex portion, a thickness of the membrane (14) varying at and/or near the inlet (18), and the first end of the membrane (14) being configured to collapse inwardly to vary a flow path size in response to changes in pressure acting on the membrane (14) wherein the valve further comprises a splint (26) that extends into the inlet defined by the first end of the membrane, the splint extending from the first end of the membrane to the second end of the base.