Membrane-Sealed Micropump Rotor for Low-Shear Liquid Delivery
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Solution Overview
Problem
Existing micropumps apply shear stress on delicate substances, contaminate liquids, and are not compact or economical for disposable applications, particularly in drug delivery devices.
Innovation Solution
A micropump design with a stator and rotor featuring a piston chamber, flexible elastic membrane, and non-axisymmetric indent on the piston portion that overlaps inlet and outlet mouths during different phases of the pump cycle, using a camming system for axial displacement, and includes sealing ribs for enhanced sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotary micropump with rotor and stator seals is used to deliver small quantities of liquid, then the pump achieves compactness and continuous rotation capability, but friction between the rotor shaft and valve seals applies shear stress on delicate substances
Solution Approach 1:
The invention extracts the harmful friction interface by eliminating direct contact between the rotor shaft and valve seals. The rotor shaft is made hollow and fluid-tight, separating the fluid pathway from the rotational mechanism, so that delicate substances never contact friction-generating surfaces.
Solution Approach 2:
The invention introduces an intermediary fluid-tight hollow rotor shaft structure that mediates between the rotational drive mechanism and the fluid being pumped. This intermediary allows continuous rotation while protecting delicate substances from shear stress by preventing direct contact with sealing surfaces.
2Object-affected harmful factors
If piston pumps or pumps with plunger and piston rod are used to avoid shear stress, then delicate substances are protected, but the pump becomes less compact and more complex
Solution Approach 1:
The invention extracts and removes the cumbersome piston rod and plunger mechanism from the system. Instead, a hollow rotor shaft performs the pumping function through rotational motion alone, achieving protection of delicate substances without the complexity and length of traditional piston mechanisms.
Solution Approach 2:
The invention substitutes the complex linear piston-rod mechanical system with a simpler rotational hollow shaft mechanism. This replacement maintains the benefit of protecting delicate substances while dramatically reducing mechanical complexity and compacting the overall device size.
3Object-affected harmful factors
If piston pumps are used to avoid shear stress, then delicate substances are protected, but reliability and safety are reduced due to lack of inherent fluid communication blocking
Solution Approach 1:
The invention extracts the fluid communication pathway from direct contact with moving mechanical parts. The hollow rotor shaft creates a sealed, isolated fluid pathway that inherently blocks unintended communication, improving reliability and safety while still protecting delicate substances.
4Productivity
If traditional micropump designs are used, then pumping function is achieved, but contamination of liquid occurs due to contact with moving rotor and stator portions
Solution Approach 1:
The invention extracts the liquid pathway from contact with moving rotor and stator portions. The hollow rotor shaft creates a dedicated, isolated fluid channel that prevents contamination while maintaining the pumping function through rotational motion.
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 shear stress, reduces contamination, ensures compactness, and allows for economical, disposable components, ensuring reliable and safe operation.
Implementation Method 1
The stator comprises a flexible elastic membrane sealingly separating the piston portion from the piston chamber
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A pump (1) comprising a stator (4) and a rotor (6) axially and rotatably movable relative to the stator, the stator (4) comprising a piston chamber (10) comprising a radial surface (30), an inlet (3) comprising an inlet mouth (28) formed in the radial surface and an outlet (5) comprising an outlet mouth (29) formed in the radial surface, the rotor (6) comprising a piston portion (13) comprising a radial surface (16), an end face (15) and a non-axisymmetric indent (14) formed between the radial surface (16) and the end face (15) of the piston portion (13), wherein the indent (14) is arranged to overlap at least partially the inlet mouth (28) over a range of angular positions of the rotor relative to the stator corresponding to a pump intake phase, and arranged to overlap at least partially the outlet mouth (29) over a range of angular positions of the rotor relative to the stator corresponding to a pump expel phase, and wherein the radial surface (16) of the piston portion (13) is configured to close the outlet mouth (29) during the pump intake phase, the inlet mouth (28) during the pump expel phase and both the inlet and outlet mouths (28) between the pump intake and expel phases. The stator (4) comprises a flexible elastic membrane (7) sealingly separating the piston portion (13) from the piston chamber (10).