Multi-stage Rotary Lobe Pump Radial Connecting Channels
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Solution Overview
Problem
Multi-stage Roots piston pumps face challenges with complex and costly designs due to large housing volumes required for connecting channels, leading to reduced pumping speed and increased power consumption.
Innovation Solution
Designing a multi-stage Roots pump with two-tooth rotary pistons and connecting channels arranged radially within intermediate walls, featuring larger inflow and outflow openings to reduce flow resistance, and optionally including antechambers and afterspaces to further minimize resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If connecting channels are arranged in the housing to convey gas between pumping stages, then gas can be conveyed from outlet to inlet, but the design becomes technically complex and requires large housing volume
Solution Approach 1:
The connecting channels are merged with the partition walls that separate adjacent pumping chambers. The partition walls serve dual functions: separating pumping chambers and providing pathways for connecting channels, thereby eliminating the need for separate housing structures and reducing overall complexity
Solution Approach 2:
The connecting channels are arranged axially within the partition walls rather than radially in the housing. This dimensional repositioning allows gas to flow between stages through the partition walls, reducing the required housing volume and simplifying the overall pump structure
2Productivity
If connecting channels are arranged in the housing, then gas can be conveyed between stages, but external dimensions and manufacturing costs increase
Solution Approach 1:
The connecting channels are integrated into the partition walls, utilizing the existing structural volume rather than requiring additional housing space. This merging reduces the overall pump volume while maintaining the necessary gas conveyance functionality between stages
Solution Approach 2:
The connecting channels are nested within the partition walls that already form part of the pump structure. This nesting approach allows the connecting channels to occupy space that would otherwise be structural, reducing the external dimensions of the pump
3Device complexity
If Z-shaped connecting channels are used in partition walls, then channels can be arranged within walls, but flow losses increase
Solution Approach 1:
The connecting channels are designed with smooth curved transitions instead of sharp Z-shaped angles. The curved geometry reduces flow separation and turbulence, minimizing energy losses while maintaining the compact within-wall arrangement
Solution Approach 2:
The channel geometry parameters are optimized to provide smooth transitions and appropriate cross-sectional areas. By adjusting the curvature radius and channel dimensions, flow losses are minimized while maintaining the compact within-wall configuration
4Device complexity
If three or more teeth per rotary lobe are used, then connecting channels can be arranged axially in partition walls, but pumping speed decreases
Solution Approach 1:
The connecting channel function is extracted from the rotary lobe structure and placed in the partition walls. This separation allows the rotary lobes to be optimized for pumping speed with two teeth, while the connecting channels provide axial flow paths through the partition walls without interfering with the lobe geometry
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 configuration enhances pumping speed and efficiency while reducing power consumption and production costs by simplifying the pump design and minimizing flow losses.
Implementation Method 1
The two rotary pistons provided in each pumping chamber are driven in opposite directions, so that gas is drawn in through the individual chambers created via a main inlet and expelled again via a main outlet
Implementation Method 2
The gas to be pumped is conveyed from the outlet of one pumping stage to the inlet of an adjacent pumping stage via connecting channels
Implementation Method 3
the inflow opening is designed such that the cross-section of the inflow opening is larger than the cross-section of the connecting chamber. The inventive design of the multi-stage Roots pump with two-toothed rotary lobes allows for a high suction capacity. By providing an inflow chamber with a large inflow opening, flow resistance can be reduced
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a multi-stage rotary lobe pump having a plurality of pump chambers (14) in a pump housing (16, 18). Said pump chambers form respective pump stages (26, 28, 30, 32, 34), each pump stage having two bidentate rotary pistons (10). The pump stages (26, 28, 30, 32, 34) are separated from each other by intermediate walls (44). Substantially radially extending connecting channels (48) are arranged in the intermediate walls (44). The connecting channels (48) are connected to an inflow chamber (40), the inflow opening (42) of which has a larger cross-section than the connecting channels (48).