Offset-Center Lobe Rotor for Stable Low-Pulsation Pump Flow
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Solution Overview
Problem
Existing volumetric pumps experience pulsating fluid flow and high vibrations due to variable fluid passage volumes and unbalanced axial and radial forces, leading to noise and increased operational costs.
Innovation Solution
A lobe rotor design with a central section offset by an angle α, forming trapezoidal grooves that balance fluid flow and forces, reducing pulsations and vibrations by dividing fluid passage volumes into balanced, progressive chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotors with straight lobes or helical teeth are used, then the pump can transport liquids with solid particles, but pulsating fluid flow and high vibrations occur due to variable fluid passage volumes
Solution Approach 1:
The rotor is divided into multiple lobes (at least three) that create multiple fluid passage chambers simultaneously during rotation. This segmentation allows the fluid flow to be divided into multiple smaller chambers rather than one large variable chamber, reducing the pulsating effect and stabilizing the overall fluid flow while maintaining transport capability.
Solution Approach 2:
The lobes are designed with asymmetric profiles where the radial extension varies along the axial direction. Specifically, the lobes have different heights at different positions, creating asymmetric fluid passage chambers that balance the variable volumes throughout the rotation cycle, thereby reducing pulsations while preserving the ability to handle liquids with solid particles.
2Stability of the object's composition
If rotors with helical teeth are used to reduce pulsating effect, then fluid flow stability improves, but strong axial forces are generated requiring precise and expensive supporting devices
Solution Approach 1:
The asymmetric lobe design creates counterbalancing forces during rotation. By carefully designing the lobe profiles with varying radial extensions, the centrifugal forces and pressure distributions are balanced to minimize net axial forces on the rotor shaft, eliminating the need for complex thrust containment devices while maintaining flow stability.
Solution Approach 2:
The lobes feature curved surfaces with varying radial extensions rather than straight or helical geometries. These curved profiles create smooth transitions in fluid passage volumes and distribute forces more evenly during rotation, reducing peak axial forces while maintaining stable fluid flow without requiring precision shaft supports.
3Device complexity
If rotors with straight lobes are used, then device complexity is reduced, but pulsating fluid flow and high vibrations increase with operating speed
Solution Approach 1:
The lobe design incorporates dynamic characteristics through varying radial extensions along the axial direction. The lobes are not static simple shapes but have profiles optimized for different rotational positions, creating a dynamically balanced fluid passage system that reduces vibrations and noise across a range of operating speeds while maintaining structural simplicity.
Data Source
Figure 1~3
Figure 4~6
Figure 7
AI summary
Described is a lobe rotor (1) comprising a first (2) and a second (3) section defining the respective ends of the rotor (1), spaced apart from each other along a longitudinal axis (X) of extension of the rotor; each first (2) and second (3) section having the same profile comprising at least two lobes (4, 5) extending radially, with respect to a hub (1a) through which the central axis (X) the rotor passes and whose extension defines respective vertices and corresponding grooves (G4, G5) of the rotor (1); the first (2) and second (3) section being positioned relative to each other with their respective profiles coinciding along the axis (X) the rotor; a third central section (6) interposed between the first (2) and the second section (3), along the axis (X) the rotor, and having the same profile as the first (2) and second (3) end section, that is to say, comprising at least two lobes (4, 5) with a radial extension whose extension defines respective vertices and corresponding grooves (G4, G5); the third section (6) is rotated about the axis (X) of the rotor, with respect to the first (2) and second (3) cross section in such a way as to offset by an angle (α) the respective vertices and grooves (G4, G5) of the at least two lobes (4, 5) with respect to the vertices and grooves (G4, G5) of the lobes (4, 5) of the first (2) and second (3) section; a first (7) and a second (8) joining body between the first (2) and the second (3) end section and the third central section (6); each first (7) and second (8) joining body having inclined connecting surfaces, along the axis (X) of the rotor, for connecting the respective vertices and grooves (G4, G5) of the at least two lobes (4, 5) of the first (2), second (3) and third (6) section so as to form at least two grooves (G4, G5) opposite each, other along the axis (X) of the rotor, with undulating extension and each formed at least by the central surface (9) of the third central section (6) having the edges parallel to the axis (X) the rotor and by two surfaces (10, 11) formed respectively by the first (7) and second (8) joining body and having the edges inclined and converging towards the central surface (9).