Stirring Device Homogeneous Bubble Distribution
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Solution Overview
Problem
Existing stirring devices for activated sludges produce air bubbles with non-homogeneous size distribution, often resulting in undesirably large bubbles.
Innovation Solution
A stirring device with a covering element that creates an annular gap between the stirring body and the covering element, allowing air to be supplied coaxially through the gap, which helps in forming air bubbles with a smaller, more uniform diameter through the selection of gap width and the use of radially extending shear ribs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If air is supplied to a funnel-like recess on the underside of a hyperboloid-like stirring body, then air bubbles are created in the activated sludge, but the bubble size distribution is non-homogeneous with undesirably large bubbles
Solution Approach 1:
The air supply opening is segmented by the covering element into multiple smaller outlets forming an annular gap, which divides the air flow into numerous small bubbles instead of a few large bubbles, achieving homogeneous bubble size distribution
Solution Approach 2:
The covering element creates a localized annular gap with specific width (1-15 cm) at the circumferential boundary, concentrating the air outlet in a controlled region that generates uniform bubble sizes through the interaction with the liquid medium and shear ribs
2Manufacturing precision
If the annular gap width is reduced to create smaller bubbles, then bubble diameter decreases, but the gap becomes too narrow for proper air flow distribution
Solution Approach 1:
The air outlet is transformed from a point or small opening into an annular gap with radial extent, utilizing the radial dimension to distribute air flow while maintaining controlled gap width, enabling both small bubble formation and proper air flow distribution
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
The solution achieves a homogeneous bubble distribution with a relatively small average bubble diameter and monomodal size distribution, effectively preventing large bubbles and enhancing dispersion throughout the liquid medium.
Implementation Method 1
essentially radially running shear ribs extending from a radially outer area of the lower circumferential surface can be provided
Data Source
AI summary
A stirring device for activated sludges contained in a basin includes a stirring body having a hyperboloidal wall with a lower circumferential surface, and a funnel-shaped recess underside the hyperboloidal wall; a shaft attached to the stirring body; an air supply line adapted to extend along a bottom of the basin and having a vertical section to supply air into the recess of the stirring body; a disk arranged underside the stirring body and spaced away from the lower circumferential surface to form an annular gap therewith; and shear ribs formed under the lower circumferential surface to extend along the lower circumferential surface and surround the annular gap. The vertical section of the air supply line extends coaxially through the disk in relation to the shaft so that when the stirring body is rotating, the shear ribs distribute air bubbles through the annular gap.