Segmented Pump Membrane Radial Stretching Vibration Reduction
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Solution Overview
Problem
Membrane pumps used in medical ventilation monitoring and gas analysis are limited by their design, which restricts elastic behavior, leading to reduced stroke length, maximum pressure, and fatigue life, while also causing noise and mechanical vibrations that affect measurement accuracy.
Innovation Solution
A membrane pump design featuring a pump housing with an enlarged surface and a membrane element with a central section that allows radial movement and stretching, decelerating the pump stroke progressively to reduce vibrations and increase elasticity, enabling longer strokes and extended membrane life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the membrane is fixed rigidly at the edges to define a pump area, then the pump structure is simple and stable, but the membrane elasticity is limited, stroke length is reduced, and fatigue life is decreased
Solution Approach 1:
The membrane is divided into a fixed central pump area and a peripheral elastic region. The central area with radius r1 is rigidly clamped to define the pump area, while the outer region with radius r2 maintains elastic behavior for stretching during pumping strokes. This segmentation allows the membrane to have both structural stability and elastic compliance, extending fatigue life by reducing stress concentration at fixed boundaries.
Solution Approach 2:
Different regions of the membrane are given different mechanical properties. The central region has fixed boundary conditions for stable pumping, while the peripheral region has free boundary conditions that allow radial stretching and elastic deformation. This local differentiation of mechanical constraints enables the membrane to achieve extended elastic behavior without compromising overall structural stability.
2Length of moving object
If the membrane area is increased to allow more stretching, then the stroke length increases, but the pump force is reduced due to distributed area
Solution Approach 1:
The membrane area is segmented into a pump area (radius r1) that generates force and an elastic reserve area (radius r2) that provides stretching capacity. The pump force is concentrated on the smaller central area, maintaining high force density, while the outer elastic region extends the stroke length through radial stretching without diluting the pump force.
Solution Approach 2:
The membrane utilizes radial stretching in the elastic region to extend stroke length, adding a dimensional aspect to the pumping mechanism. Instead of increasing the pump area linearly, the system uses radial expansion of the elastic region to achieve longer strokes while keeping the force-generating central area compact and forceful.
3Productivity
If the pump stroke stops instantly when the flat membrane meets the chamber surface, then the pump chamber is fully utilized, but mechanical vibrations and noise are generated
Solution Approach 1:
The pump chamber is designed with a curved bottom surface instead of a flat surface. This curvature allows the membrane to follow a smooth arc during the pumping stroke, enabling gradual deceleration as the membrane approaches the chamber bottom. The curved geometry eliminates sudden stops and impacts, reducing mechanical vibrations and noise while maintaining complete chamber utilization for pump efficiency.
4Productivity
If the membrane is designed for longer stroke length, then more volume is pumped per stroke, but the fatigue stress on the membrane increases
Solution Approach 1:
The membrane is segmented into a fixed central region and an elastic peripheral region. The elastic region undergoes the stretching and deformation during long strokes, while the fixed central region remains stable and stress-free. This segmentation protects the membrane from fatigue stress by concentrating deformation in the elastic reserve area, allowing long stroke lengths that increase volume pumped per stroke without compromising membrane strength.
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 achieves a longer pump stroke with reduced fatigue stress, increased membrane life, and lower mechanical vibrations, resulting in a more efficient and quieter operation with higher pressure capabilities.
Implementation Method 1
A portion of the membrane element is slidably clamped between the enlarged surface and the second pump house member in such a way that the clamped portion is allowed to move radially and to stretch when a force is applied on said membrane
Implementation Method 2
This will not only provide a silent the stop of the stroke but also reduce the mechanical vibrations due to the progressive motion deceleration
Data Source
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AI summary
A pump comprising a pump housing member (1) having a chamber (21) with inner walls and an open end having a first area (25), the pump housing member (1) comprises an enlarged surface surrounding the open end of the chamber (21). The pump further comprises a second pump housing member (5) and a membrane element (32) with a second area (27). The membrane element (32) has a first central section having a third area (28) with same size as the first area (25) of the open end of the chamber (21). The membrane element (32) is arranged on the pump housing element (1) with the first central section positioned over the open end, forming a sealed chamber. A portion of the membrane element (32) is slidably clamped between the enlarged surface and the second pump housing member (5).