Volumetric Membrane Pump Secondary Passage Air Evacuation
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Solution Overview
Problem
Volumetric membrane pumps face issues with air locks trapped in the intermediate chamber, which can create a vacuum and affect the operation and duration of the pump during the compression stroke, making it difficult to achieve a complete filling without manual intervention.
Innovation Solution
Incorporating a secondary passage in the guide cylinder that allows trapped air to escape while maintaining lubricating oil during the compression stroke, with a cross-section smaller than 0.2 mm² to minimize oil leakage and ensure efficient air evacuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the intermediate chamber is filled with lubricating oil during the compression stroke, then the membrane thrust is improved, but air locks may remain trapped creating a vacuum that affects pump operation
Solution Approach 1:
The communication between the intermediate chamber and casing is divided into two separate passages: a primary passage for oil filling during compression stroke, and a secondary passage for air evacuation during the suction stroke. This segmentation allows both functions to occur simultaneously without interference, resolving the contradiction between maintaining oil pressure for membrane thrust and removing trapped air that would create vacuum effects.
2Reliability
If manual intervention is used to remove air locks by overturning and shaking the pump, then air evacuation is improved, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The pump is designed with a secondary passage that automatically evacuates air during the normal suction stroke without requiring manual intervention. The system serves itself by using the existing piston movement and pressure differential to remove air locks, eliminating the need for complex manual evacuation procedures while maintaining reliable air removal.
3Reliability
If the secondary passage has a large cross-section, then air evacuation is improved, but lubricating oil leakage increases
Solution Approach 1:
The secondary passage is designed with a specific, limited cross-sectional area that is sufficient for air evacuation but too small for significant oil leakage. This local optimization of passage dimensions allows the system to selectively permit air removal while maintaining oil containment, resolving the contradiction between effective air evacuation and oil loss prevention.
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 prevents air stagnation in the intermediate chamber, ensuring consistent pump operation and extending its duration by allowing easy air evacuation without compromising the pressure of the lubricating oil.
Implementation Method 1
the air possibly trapped inside the intermediate chamber may always and easily flow towards the internal volume of the casing through the secondary passage
Implementation Method 2
the lubricating oil also fills the intermediate chamber of the cylinder and being incompressible, allows actively supporting the membrane during the compression stroke
Implementation Method 3
a piston fixed to the flexible membrane and slidable inside the guide cylinder between an upper dead centre position and a lower dead centre position
Data Source
Figure 1
Figure 2
AI summary
A volumetric membrane pump (100) is described, comprising: a guide cylinder (110), a flexible membrane (150) placed so as to close an axial end of the guide cylinder (110), a head (155) designed to define a pumping chamber (160) with the flexible membrane (150), a piston (115) fixed to the flexible membrane (150) and slidable inside the guide cylinder (110) between an upper dead centre position and a lower dead centre position, an intermediate chamber (195) defined inside the guide cylinder (110) between the flexible membrane (150) and the piston (115), a casing (140) defining an internal volume (145) suitable for being filled with lubricating oil, at least one un primary passage (205) suitable for placing the intermediate chamber (195) in communication with the internal volume (145) of the casing (140) when the piston (115) is in the lower dead centre position, and at least one secondary passage (210) suitable for placing the intermediate chamber (195) in communication with the internal volume (145) of the casing (140) when the piston (115) is in the upper dead centre position.