Regenerative Blower-Compressors: Shaft Bypass Venting for Seal Wear
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Solution Overview
Problem
Regenerative blowers-compressors face issues with fluid leakage and lubricant loss due to pressure differentials, leading to reduced efficiency and seal wear, particularly in applications requiring clean fluid streams.
Innovation Solution
The design incorporates ports to divert leaked fluid from high-pressure regions to low-pressure regions within the blower, increasing volumetric efficiency and reducing pressure differentials across bearings and seals, thereby minimizing lubricant loss and seal wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a radial shaft seal is used to seal the drive shaft to the sidewall, then fluid leakage is reduced, but friction and seal wear increase
Solution Approach 1:
The patent introduces an intermediary fluid pathway (ports and passages) that mediates between the high-pressure and low-pressure regions. This intermediary system allows controlled fluid movement that reduces the pressure differential across the seal, thereby reducing both leakage and friction simultaneously rather than treating them as separate problems
Solution Approach 2:
The patent changes the pressure parameter distribution around the seal by introducing ports that equalize pressure between different regions. By modifying the pressure field (a key physical parameter), the system reduces the driving force for both leakage and friction, achieving improvement in both aspects
2Productivity
If pressure differential across bearings and seals is increased to improve compression, then compression efficiency improves, but seal wear and lubricant loss increase
Solution Approach 1:
The patent segments the pressure field into distinct zones using ports and passages, allowing different pressure conditions in different regions. This segmentation enables the compression function to operate with high pressure differential while the seal region experiences reduced pressure differential, protecting seal life
Solution Approach 2:
The patent introduces an intermediary fluid pathway system that mediates between the compression region (high pressure differential needed) and the seal region (low pressure differential needed for reliability). This intermediary system allows the two conflicting requirements to coexist in different spatial zones
3Loss of substance
If shaft seals are added to eliminate bypass fluid, then fluid leakage is reduced, but device complexity increases
Solution Approach 1:
The patent enables the system to self-regulate fluid pathways using the existing pressure differentials. The ports and passages allow the pressure field itself to drive the fluid management, eliminating the need for active control mechanisms or complex seal assemblies while still achieving bypass fluid elimination
Solution Approach 2:
The patent extracts the fluid management function from complex mechanical seals and implements it through simpler port and passage geometry. By taking out the sealing function from mechanical components and implementing it through fluid pathway design, the system reduces device complexity while maintaining effectiveness
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 approach enhances the operational efficiency and extends the functional life of seals and bearings by recirculating leaked fluid, improving fluid flow and reducing friction-related losses.
Implementation Method 1
the drive shaft is sealed to the sidewall by a radial shaft seal within the shaft chamber
Implementation Method 2
a bearing rotatably connecting the drive shaft to the housing
Data Source
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AI summary
A regenerative blower-compressor (50) includes an impeller (51) mounted to a drive shaft (70) within a housing (55) including a channel (65) extending from an inlet (66) adjacent to a low fluid-pressure region (81) of the channel (65) to an outlet (67) adjacent to a high fluid-pressure region (82) of the channel (65), the impeller (51) extends radially outward through an annular volume (75) within the housing (55) from the drive shaft (70) to blades (80) in the channel and is configured to rotate for rotating the blades (80) through the channel for forcing fluid through the channel (65) from the inlet (66) to the outlet (67) in response to rotation of the drive shaft (70), the drive shaft (70) extends from the impeller (51) within the annular volume (75) into a shaft chamber within the housing (55) configured to receive fluid from the high fluid-pressure region (82) of the channel (65), and a port (130) configured to vent fluid directly from the shaft chamber (120) into the low fluid-pressure region (81) of the channel (65).