Ventilator Expiration Valve Structure for Low-Noise Pressure Stability
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Solution Overview
Problem
Existing expiration valves in ventilators often produce unpleasantly loud noises and can cause oscillating pressure fluctuations, leading to malfunctions such as autotrigger or autocycle, where pressure fluctuations are incorrectly detected as the end of the expiration phase, potentially endangering the patient.
Innovation Solution
The expiration valve features a valve body with at least one stiffening rib around the fluid inlet, which increases the area moment of inertia and torsional stiffness, reducing noise and pressure repercussions, and a valve base that bulges in the axial direction to form a streamlined fluid flow path, enhancing the valve's sensitivity to expiration phase changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the expiration valve uses a conventional valve body design, then the structure is simple and easy to manufacture, but it generates loud noises and oscillating pressure fluctuations that cause malfunctions
Solution Approach 1:
The valve body incorporates stiffening ribs at specific locations (around the fluid inlet) to increase local torsional stiffness and area moment of inertia. This localized structural enhancement reduces noise and pressure fluctuations without requiring complete redesign of the entire valve body, maintaining manufacturing simplicity while eliminating harmful effects.
Solution Approach 2:
The valve base is designed with a bulge in the axial direction, adding a dimensional feature that streamlines the fluid flow path. This three-dimensional modification to the valve base structure improves flow characteristics and reduces turbulence-induced noise and pressure fluctuations without significantly complicating manufacturing.
2Object-generated harmful factors
If the valve body is made more rigid to reduce noise, then noise generation is suppressed, but the valve becomes less sensitive to expiration phase changes
Solution Approach 1:
Stiffening ribs are strategically positioned around the fluid inlet area where they most effectively reduce noise-generating vibrations, while the valve membrane and its surrounding structure maintain appropriate flexibility for detecting expiration phase changes. This localized approach to stiffening ensures noise reduction without compromising detection sensitivity.
Solution Approach 2:
The valve body is segmented into regions with different stiffness characteristics: the main body and inlet area are stiffened to reduce noise, while the valve membrane and outlet regions maintain flexibility for sensitive detection of pressure changes during expiration phases.
3Ease of manufacture
If the valve base is made flat and simple, then manufacturing is easier, but fluid flow paths are not streamlined causing turbulence and noise
Solution Approach 1:
A bulge is added to the valve base in the axial direction, creating a three-dimensional streamlined shape that guides fluid flow smoothly through the valve. This dimensional modification improves flow characteristics and reduces turbulence-induced noise while remaining compatible with standard manufacturing processes like injection molding.
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 solution significantly suppresses noise generation and pressure reactions, improving the valve's ability to reliably detect the end of the expiration phase, thereby reducing the risk of autotrigger malfunctions and enhancing patient safety.
Implementation Method 1
The valve body has at least one stiffening rib formed around the fluid inlet. The stiffening rib or ribs are suitable for stiffening the valve base, in particular in a bulging area that surrounds the fluid inlet. This leads to an increase in the area moment of inertia of the valve body, in particular of the valve base, over the cross section of the fluid flow path.
Implementation Method 2
The valve base is designed to bulge in the axial direction in an area around the fluid inlet, forming a streamlined design. Rounded contours are formed along the fluid flow path, which promotes streamlined flow and reduces flow separation. This reduces the formation of turbulence and disturbances in the fluid flow.
Data Source
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AI summary
The present invention relates to an expiration valve (10) of a ventilation device (100), having a valve body (12) in which a fluid inlet (14) and a fluid outlet (16) for a patient's breathing air are formed, the valve body (12) at least one stiffening rib (36, 38) formed around the fluid inlet (14).