Flexible Impeller Pump With Dual Sealing Lips Against Slippage
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Solution Overview
Problem
Dual-cam flexible impeller pumps face challenges in achieving suitable operating pressure without slippage and balancing the load on the drive shaft, particularly in minimizing the size of the pump while maintaining effective sealing and preventing wear.
Innovation Solution
The flexible impeller design features two sealing elements per vane, allowing for reduced cammed sealing surface area and increased pumping vanes, along with a mounting hub that decouples the impeller from the drive shaft for easy installation and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dual-cam flexible impeller pump is designed to double pumping capacity, then productivity increases, but slippage occurs and operating pressure decreases
Solution Approach 1:
The impeller is segmented into multiple pumping vanes (at least three) that are radially distributed around the impeller body. Each vane acts as an independent sealing element that contacts the cam surface, dividing the pumping action into multiple simultaneous zones. This segmentation allows the pump to maintain pressure while doubling capacity through parallel pumping zones created by the dual-cam configuration.
Solution Approach 2:
The pumping vanes are made of flexible material with varying local properties - stiffer at the root for structural support and more compliant at the tip for effective sealing contact with the cam surface. This local quality variation ensures that each vane can independently maintain sealing pressure against the cam while withstanding the forces generated during high-capacity dual-cam operation.
2Device complexity
If a single cam is used in the pump housing, then device complexity is reduced, but asymmetric loading causes excessive wear and shaft failure
Solution Approach 1:
The invention intentionally employs a dual-cam asymmetric configuration where two cams are positioned at different angular locations around the impeller. This controlled asymmetry balances the radial and axial loads on the drive shaft by distributing pumping forces across multiple zones, preventing the excessive asymmetric loading that would occur with a single cam while maintaining manageable device complexity.
Solution Approach 2:
The dual-cam arrangement acts as a counterbalancing system where the second cam and its associated pumping vanes provide counteracting forces to the first cam system. This counterbalancing effect neutralizes the asymmetric loads generated during pumping operation, reducing wear on bearings and seals while preventing drive shaft fatigue and failure.
3Volume of moving object
If the cammed sealing surface area is reduced to minimize pump size, then volume decreases, but sealing efficiency and pressure generation are compromised
Solution Approach 1:
The pumping action is extended from a single-dimensional cam surface contact to a multi-dimensional configuration with multiple pumping vanes distributed radially around the impeller. Each vane contacts the cam surface at different angular positions, effectively increasing the sealing surface area in the radial dimension while maintaining a compact overall pump volume. This dimensional approach allows reduced pump size without sacrificing sealing efficiency.
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
This design enhances sealing efficiency, increases pumping pressure, and reduces the likelihood of shaft failure, while allowing for compact pump designs with improved reliability and ease of maintenance.
Implementation Method 1
the vanes bend when they make contact with the cam. The vanes are deflected when they make contact with the cam and this creates an increase in pressure
Implementation Method 2
As the vanes pass over the cam, the deflection of the vanes is relaxed, which creates a vacuum with respect to the inlet, thus drawing fluid into the pump
Implementation Method 3
The rotating flexible vanes are received within the housing, and form a sealing contact with the walls of the housing
Data Source
AI summary
The present invention relates to improvements in the area of flexible impeller pumps. In particular, the present invention relates to flexible impellers with improved profiles (such as dual sealing lips), which are particularly well-suited to multiple cam pumps. A novel mounting hub configuration for mounting an impeller on a drive shaft is also provided. Pumps comprising such impellers and/or mounting hubs are provided, as are associated methods of installation and removal.