Membrane Pump Variable Thickness Design
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Solution Overview
Problem
Existing membrane pumps face challenges in preventing air bubble trapping and ensuring efficient emptying of fluid, particularly in blood treatment applications, where precise control of fluid flow and pressure signals are critical.
Innovation Solution
A membrane pump design featuring a flexible member with increased thickness in the downstream direction, a dome shape, and grooves in the accumulation containers to manage fluid flow and prevent air bubble trapping, along with a blood treatment apparatus that integrates these pumps to ensure continuous and efficient blood treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the membrane thickness is increased in the downstream direction, then air bubble trapping is minimized and fluid flow efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The membrane is designed with variable thickness where the downstream portion has increased thickness compared to the upstream portion. This local quality variation optimizes fluid flow and prevents air bubble trapping in the downstream region without unnecessarily increasing the thickness of the entire membrane, thus balancing manufacturing complexity with performance improvement.
2Productivity
If grooves are added to the accumulation container walls, then fluid emptying efficiency is improved and air bubble trapping is prevented, but device complexity increases
Solution Approach 1:
The accumulation container walls are segmented with grooves that divide the wall surface into multiple sections. These grooves create controlled flow paths that facilitate efficient fluid emptying and prevent air bubble trapping by guiding fluid along specific trajectories, achieving improved productivity with a relatively simple structural modification.
3Measurement precision
If the membrane is designed with variable thickness, then end of stroke detection precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The membrane thickness parameter is deliberately varied along the downstream direction, creating a gradient structure. This parameter change provides distinct pressure characteristics at different stroke positions, improving end of stroke detection precision. The gradual variation in thickness makes the parameter changes manageable within standard manufacturing tolerances.
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 minimizes air bubble trapping, ensures efficient fluid flow, and provides a reliable pressure signal for end-of-stroke indication, facilitating synchronized operation and continuous blood treatment.
Implementation Method 1
a positive displacement pump that uses a combination of the reciprocating action of a membrane and suitable non-return check valves to pump a fluid
Implementation Method 2
Pneumatic pressure is provided through a pneumatic port to either force, with positive gas pressure, the membrane towards one wall of the pod pump cavity to minimize the pumping chamber's volume or to draw, with negative gas pressure, the membrane towards the other wall of the pod pump cavity to maximize the pumping chamber's volume
Implementation Method 3
a positive displacement pump that uses a combination of the reciprocating action of a membrane and suitable non-return check valves to pump a fluid
Data Source
Figure 1
Figure 2
Figure 3a~3e
AI summary
The present invention relates to a membrane pump and an apparatus comprising such a membrane pump. The membrane pump comprises a pumping chamber and a flexible member separating the pumping chamber into a first accumulation container and a second accumulation container. The flexible member is configured to be movable within the pumping chamber so as to vary a volume relationship between the first and second accumulation container. The second accumulation container is configured to receive an amount of working fluid to act on the flexible member and thus, in use, pump a first fluid from the first accumulation container. The first and the second accumulation container, each has an inlet opening for inlet of the respective fluid and an outlet opening for outlet of the respective fluid, the inlet opening being arranged on one side of the accumulation container and the outlet opening being arranged on the opposite side of the accumulation container. The flexible member is configured to show, when arranged in the pumping chamber and seen in a cross section along a plane extending through a pair of the inlet and outlet openings of the accumulation container, a thickness that is increased in a downstream direction.