Tri-lobe Rotor Non-smooth Curve Sealing Rotary Pump
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Solution Overview
Problem
Existing rotary pump designs for medical applications suffer from unwanted transfer of medicament between chambers due to smooth curve edges of the rotor not corresponding well with the inner peripheral wall, leading to inaccurate dose delivery.
Innovation Solution
A rotary pump design featuring a tri-lobe rotor with two peripheral curved surfaces sharing a common apex, where one portion defines a non-smooth curve, ensuring a tight seal between the rotor and the rotor housing, preventing medicament transfer between chambers, and utilizing a flexible material like silicon to eliminate the need for separate sealing members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If smooth curve edges are used on the rotor lobes, then the rotor surface is continuous and easier to manufacture, but gaps occur between the rotor and rotor housing causing unwanted transfer of medicament between chambers
Solution Approach 1:
The rotor lobe edges are designed with non-smooth curve portions that create localized tight sealing regions against the rotor housing, while other portions of the rotor surface maintain smooth curves for ease of manufacture. This local modification at the critical sealing zones prevents gaps and medicament transfer between chambers without requiring the entire rotor to be complex.
2Device complexity
If standard Wankel three-lobe or two-lobe rotor designs are used, then the pump mechanism is well-established and easier to implement, but unwanted transfer of medicament occurs reducing dose accuracy
Solution Approach 1:
The invention modifies only the critical edge portions of the rotor lobes with non-smooth curves to achieve proper sealing, while maintaining the overall simple three-lobe or two-lobe rotor structure. This localized modification preserves the simplicity of the pump mechanism while eliminating the medicament transfer problem that reduces dose accuracy.
3Reliability
If flexible seals are positioned at the apex of smooth curve lobes, then sealing capability is improved, but the smooth curve edges still do not correspond well with the inner peripheral wall causing gaps and medicament transfer
Solution Approach 1:
Instead of adding flexible seals to smooth curve lobes, the invention inverts the approach by modifying the rotor lobe edges themselves with non-smooth curves that directly correspond to the inner peripheral wall geometry. This creates inherent tight sealing without relying on additional flexible seal components, preventing medicament transfer and ensuring accurate volumetric flow.
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 ensures precise and accurate volumetric flow of medicament by preventing unwanted transfer, enhancing dose accuracy and reliability in medical infusion and injection procedures.
Implementation Method 1
The rotor is preferably fabricated of a flexible material such that the apexes do not require separate sealing members. One such flexible material is silicon.
Data Source
Figure 1
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Figure 3A~3B
AI summary
A rotary pump is presented for use in a medicament delivery device, where the pump has a back plate having an inner surface and a rotor housing is positioned adjacent to the back plate having a peripheral wall. A front plate support is connected to the back plate and a flexible front plate is positioned between the front plate support and the rotor housing. The pump is rotated using a planetary gear transmission, where an eccentric shaft is operatively connected to the planetary gear mechanism. A rotor is rotationally fixed to the eccentric shaft and movably positioned within rotor housing. The rotor has three lobes, where each lobe has two peripheral curved surfaces sharing a common apex, where a first portion of each peripheral surface adjacent to the apex defines a non- smooth curve.