Helical Gear Pump Rotor Volume Equalization
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Solution Overview
Problem
Eccentric screw pumps with multiple chambers face issues with cavitation due to wear, leading to suboptimal conveying capacity.
Innovation Solution
The design ensures equal chamber volumes between the stator and rotor by adjusting the rotor's cross-section, pitch, and eccentricity in the longitudinal direction, allowing for optimal performance and extended service life through materials like chrome-coated ceramics and elastomeric components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple chambers are used in the eccentric screw pump, then the conveying capacity is increased, but wear causes chamber volume increases and cavitation occurs, reducing conveying capacity
Solution Approach 1:
The patent applies parameter changes by making the rotor cross-section variable along its longitudinal direction. Specifically, the rotor has a larger cross-section at the inlet end and a smaller cross-section at the outlet end. This gradual change in cross-sectional parameters compensates for wear-induced volume increases, maintaining optimal chamber volumes and preventing cavitation while preserving high conveying capacity.
2Manufacturing precision
If the rotor cross-section is decreased in the longitudinal direction, then chamber volume can be maintained despite wear, but the structural complexity of the rotor increases
Solution Approach 1:
The patent implements local quality by giving different cross-sectional dimensions to different portions of the rotor along its longitudinal direction. The inlet portion has a larger cross-section while the outlet portion has a smaller cross-section. This localized variation in geometric quality allows each section to compensate for wear in its specific operating zone, maintaining consistent chamber volumes without requiring complex adjustable mechanisms.
Data Source
AI summary
The invention relates to an eccentric screw pump (100), in particular for conveying viscous, highly viscous and abrasive media, having a longitudinal direction L, having a conical, helically wound, at least single-start rotor (1) having a gradient h, having at least one eccentricity (e1, e2, e3, . . . en) and at least one cross-section d that is rotatably arranged in a single or multi-start conical stator (2) wherein a plurality of chambers (3, 4, 5 . . . n) each having a volume (V3, V4, V5 . . . Vn) is formed between the rotor (1) and stator (2) that serve to convey the medium and wherein the chambers (3, 4, 5 . . . n) between the stator and the rotor are limited by a sealing line D. The volumes (V3, V4, V5 . . . Vn) of each individual chamber (3, 4, 5 . . . n) between the stator (2) and the rotor (1) are equal.