Stirring Device Propeller Axial Flow Activated Sludge
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Solution Overview
Problem
Existing stirring devices for activated sludges lack efficiency in generating a directed flow, which limits their effectiveness in improving mixing and processing within the basin.
Innovation Solution
A propeller is attached to the shaft of the stirring device, generating an axial flow directed upwards, combined with transport ribs that accelerate the flow away from the circumferential boundary, and shear ribs to create air bubbles, enhancing mixing efficiency. The propeller wings are designed with a decreasing angle of attack radially and made of elastic material for speed-dependent efficiency, and multiple propellers can be stacked for increased flow acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional stirring devices are used, then the structure is simple, but the stirring efficiency is insufficient due to lack of directed flow generation
Solution Approach 1:
The patent combines multiple functional elements into a single integrated stirring device: the stirring body with transport ribs, the propeller for axial flow generation, and the shaft system with bearing support all merge into one unified structure. This integration achieves directed flow generation and improved stirring efficiency without requiring multiple separate devices, thus resolving the contradiction between productivity improvement and device complexity
Solution Approach 2:
The propeller is designed with adjustable pitch angle capability, allowing the blade angle to be dynamically adjusted to optimize flow generation under different operating conditions. The elastic material for propeller wings provides dynamic adaptation to varying rotational speeds, with the angle of attack increasing as speed increases. This dynamic characteristic enables the device to maintain optimal stirring efficiency across different operational states
2Speed
If multiple propellers are stacked on the shaft, then the flow acceleration is increased, but the device complexity increases
Solution Approach 1:
The flow generation function is segmented into multiple propellers stacked along the shaft, with each propeller contributing to the overall axial flow. This segmentation allows the system to achieve higher flow acceleration through cumulative effect while maintaining a modular structure that can be manufactured and assembled using standard procedures, thus managing the complexity increase
Solution Approach 2:
Instead of increasing the diameter or complexity of a single propeller, the solution adds propellers in the axial dimension (along the shaft length). This dimensional approach achieves flow acceleration through stacking multiple units in series, utilizing the available axial space to multiply the flow-generating effect without proportionally increasing overall device complexity
3Speed
If transport ribs bend from radial to tangential direction, then the flow acceleration on the upper side is increased, but the manufacturing complexity increases
Solution Approach 1:
The transport ribs are designed with a curved geometry that transitions from a radial direction at the base to a tangential direction at the tip. This curved configuration naturally guides the sludge flow along the upper side of the stirring body, accelerating the flow without requiring complex mechanical joints or assembly steps. The curvature can be achieved through standard forming processes, balancing flow performance with manufacturability
Solution Approach 2:
The transport rib geometry is optimized by varying parameters such as the curvature radius, rib height, and spacing along the radial direction. These parameter changes allow the ribs to effectively redirect flow from radial to tangential motion, achieving flow acceleration while maintaining a structure that can be manufactured using conventional techniques with appropriate tooling
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 significantly improves stirring efficiency by increasing pressure on the upper side of the stirring body and enhancing flow directionality, preventing unwanted movements and ensuring precise rotary motion, thus optimizing the mixing process.
Implementation Method 1
at least one propeller is attached to the shaft which generates a flow directed towards the upper side of the stirring body during a rotation of the stirring body in the direction of rotation. Due to this flow, the pressure on the upper side of the stirring body is increased.
Implementation Method 2
With the transport ribs a still more efficient flow directed away from the circumferential boundary of the stirring body can be generated in the basin.
Implementation Method 3
A plurality of essentially radially running shear ribs can be provided on an underside opposite the upper side. The shear ribs are used to swirl the air supplied on an underside of the stirring body and thus make air bubbles.
Implementation Method 4
The propeller wing can be made of an elastic material so that the angle of attack increases as the speed increases, in particular in radially outer areas.
Data Source
AI summary
The invention relates to a stirring device for activated sludges comprising a hyperboloid stirring body (2) attached to a shaft (1), wherein a plurality of transport ribs (3) are provided on the top (O) of the stirring body (2) running toward the circumferential boundary (UM) thereof, wherein the transport ribs (3) have an oblique course, at least in sections, relative to a radial direction, and wherein an oblique position of the transport ribs (3) is selected such that, when the stirring body (2) rotates in a predetermined rotational direction (R), a flow is generated that is directed radially outward away from the circumferential boundary (UM) of the stirring body (2). In order to improve the efficiency of the stirring device, the invention proposes that at least one propeller (6) be attached to the shaft (1) that, when the stirring body (2) rotates in the rotational direction (R), generates a flow (A) directed toward the top (O) of the stirring body (2).