Membrane Pump Stroke Deceleration via Bevelled Chamber

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Solution Overview

Problem

Membrane pumps used in medical ventilation monitoring and gas analyzers face challenges with vibration-induced noise, limited stroke length, and fatigue life due to their conventional design, which affects measurement accuracy and reliability.

Innovation Solution

A membrane pump design featuring a central section thicker than the periphery section with beveled inner walls in the pump chamber, allowing for progressive deceleration of the pump stroke, reducing mechanical vibrations, and enabling a stronger force towards the end of the stroke, thus enhancing sealing and increasing the pump's pressure and fatigue life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a flat membrane with fixed edges is used in a conventional pump chamber, then the pump structure is simple and compact, but the stroke length is limited and mechanical vibrations occur causing noise

Engineering Contradiction:
Improvepump structureVSAvoidmechanical vibrations and noise
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The invention applies curvature by replacing the flat membrane with a domed membrane and the flat pump chamber bottom with a curved surface. This spherical/curved geometry allows the membrane to flex more effectively during pumping strokes, increasing stroke length while the progressive contact with the curved surface prevents sudden stops that cause vibrations and noise.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention implements local quality by varying the membrane thickness - the central section is made thicker than the periphery section. This local structural differentiation allows the membrane center to maintain structural integrity for longer stroke lengths while the thinner periphery remains flexible for sealing, thereby reducing vibrations without compromising pump simplicity.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the pump chamber has a flat bottom or concave surface, then the manufacturing is simple, but the pump stroke stops instantly causing mechanical vibrations and noise

Engineering Contradiction:
Improvepump chamber fabricationVSAvoidpump stroke vibrations
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The pump chamber bottom is designed with a curved surface rather than flat or simple concave geometry. This curvature creates a progressive deceleration profile during the pump stroke, where the membrane gradually contacts the chamber surface rather than stopping instantly, thereby reducing mechanical vibrations and noise while remaining manufacturable.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Force

If the membrane area is increased to maximize pump pressure, then the pump force is improved, but the membrane stretching increases reducing fatigue life

Engineering Contradiction:
Improvepump forceVSAvoidmembrane fatigue life
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The membrane is designed with non-uniform thickness where the central section is thicker and the periphery is thinner. This local quality differentiation allows the membrane to be fixed at a larger diameter (increasing effective pump area and force) while the thicker central section experiences less stretching during operation, thereby extending fatigue life without sacrificing pump force.

Inventive Principle:
Principle #3Local quality

4Loss of energy

If a smaller pump design is implemented to reduce size and power consumption, then energy loss is reduced, but the pump pressure capability is limited

Engineering Contradiction:
Improvepower consumptionVSAvoidpump pressure
Core Design Contradiction:
Loss of energyVSStress or pressure

Solution Approach 1:

By making the central membrane section thicker, the invention enables a smaller overall pump design to generate higher pressures. The thicker central section concentrates the pumping force more effectively, allowing increased pressure capability in a compact form factor with reduced power consumption.

Inventive Principle:
Principle #3Local quality

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 reduced mechanical vibrations, silent operation, and increased pump pressure while extending the membrane's life by allowing for a longer stroke with less stretching, thereby improving the reliability and accuracy of gas composition monitoring in medical applications.

Implementation Method 1

the central section is thicker than the periphery section... allowing for progressive deceleration of the pump stroke, reducing mechanical vibrations

Methodology Applied
Scientific EffectProgressive deceleration:

Implementation Method 2

A membrane pump design featuring a central section thicker than the periphery section with beveled inner walls in the pump chamber, allowing for progressive deceleration of the pump stroke

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2733354B1Progressive pump force regulation
Publication Date: 2020.06.17 SHENZHEN MINDRAY BIO MEDICAL ELECTRONICS CO LTD
  • EP2733354B1 patent drawingFigure 1
  • EP2733354B1 patent drawingFigure 2
  • EP2733354B1 patent drawingFigure 3

AI summary

A pump comprising a membrane element and a pump housing having a chamber with bevelled inner walls. The chamber comprises an open end having a third area. The membrane element has a first area, and comprises a central section with a second area which is surrounded by a periphery section. The central section is thicker than the periphery section. Further, the second area of the central section is smaller than the third area of the open end of the chamber and the membrane element is arrangable over said pump housing forming a sealed chamber, whereby the central section of the membrane element is arranged over the open end, and the central section is protruding away from the chamber.