Membrane Pump Inversion via Pressure Port
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Solution Overview
Problem
Existing membrane pumps face challenges in achieving long membrane life, accuracy, and efficiency due to stress and wear from the pumping action, which limits their operational reliability and effectiveness.
Innovation Solution
A membrane pump design featuring an elongate cavity with a specific width-to-depth ratio, a pre-deformed non-elastomeric membrane, and a pressure port system that allows the membrane to invert between stable states under pressure, reducing stress and enhancing durability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastomeric membrane is used in a conventional pump cavity, then the membrane can be clamped to create compressive forces improving membrane life, but the membrane is still subject to stress and wear from pumping action limiting operational reliability
Solution Approach 1:
The patent changes the geometric parameters of the pump cavity by introducing a specific width-to-depth ratio (8:1 to 16:1) and uses pre-deformed non-elastomeric membranes with controlled thickness (0.002 to 0.025 inches) to optimize stress distribution and membrane performance during pumping cycles
Solution Approach 2:
The patent employs non-elastomeric membrane materials such as fluoropolymers (polytetrafluoroethylene, perfluoroalkoxy polymer resin, or fluorinated ethylenepropylene) that combine chemical corrosion resistance with mechanical durability, creating a composite solution that addresses both longevity and stress resistance
2Manufacturing precision
If the membrane is made thinner to improve flexibility and pumping accuracy, then pump volume accuracy improves, but the membrane becomes more susceptible to stress and wear
Solution Approach 1:
The patent optimizes the membrane thickness parameter within a specific range (0.002 to 0.025 inches) and controls the cavity width-to-depth ratio (8:1 to 16:1) to achieve the optimal balance between flexibility for accurate pumping and sufficient thickness for durability
Solution Approach 2:
The patent creates different structural conditions in different regions of the membrane system by designing the elongate cavity shape and pre-deforming the membrane to distribute stress evenly across the membrane surface, preventing localized stress concentrations that would compromise durability
3Productivity
If the cavity depth is increased to allow greater membrane movement for higher pumping efficiency, then productivity improves, but the membrane experiences greater stress and reduced life
Solution Approach 1:
The patent defines a specific width-to-depth ratio range (8:1 to 16:1) that optimizes the cavity geometry to provide sufficient membrane movement for efficient pumping while maintaining a depth that limits excessive stress on the membrane
Solution Approach 2:
The patent pre-deforms the non-elastomeric membrane before installation to create initial compressive forces and establish optimal stress distribution patterns that enable efficient pumping cycles while protecting the membrane from excessive stress during operation
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 results in a membrane pump with extended life, improved accuracy, and enhanced efficiency, with minimal membrane stress and efficient fluid transfer, leading to reduced operational costs and increased reliability over time.
Implementation Method 1
can be caused to invert from one stable state to the other stable state by application of positive or negative pressure to the cavity via the pressure port
Implementation Method 2
the non-elastomeric membrane is resistant to corrosion by chemicals
Data Source
AI summary
A pump that has a cavity (13) in which is located a non-elastomeric membrane (14). An inlet (24) opens into the cavity (13) and is associated with a valve (27). A valve (28) is likewise provided in an outlet (25). Also opening into cavity (13) is a port (22) to which a negative or positive pressures can be applied whereby the membrane (14) can be moved between its two stable states corresponding to completion of inlet and exhaust of a pumping cycle.