Stirrer Hub Recesses for Contamination-Resistant Blade Assembly
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Solution Overview
Problem
Existing stirrer designs suffer from contamination issues due to gaps between the hub body and propeller blades, leading to performance degradation and increased maintenance needs.
Innovation Solution
A stirrer design with a hub body featuring depressions for blade feet and recesses on the wall, where the blades protrude into the recesses, creating secondary flows that prevent dirt adhesion and a cover to keep the hub body clean, along with a conical bottom element for easy assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate production of hub body and propeller blades is used, then manufacturing flexibility is improved, but contamination in the gap region increases
Solution Approach 1:
The propeller is divided into separate blades and hub body that can be produced independently and assembled later. The blade feet are received in depressions in the hub body, allowing separate manufacturing while maintaining a contamination-resistant design through the integrated recesses and secondary flows mechanism.
Solution Approach 2:
The invention converts the harmful gap region where contamination accumulates into a beneficial feature by creating recesses in the hub body wall that extend into the depressions. These recesses generate secondary flows that actively prevent dirt and fiber accumulation, transforming the contamination-prone gap into a self-cleaning structure.
2Reliability
If recesses are added to prevent contamination, then reliability is improved, but device complexity increases
Solution Approach 1:
The recesses are merged with the existing depressions for receiving blade feet. The recesses extend into the depressions from the outer surface of the hub body wall, combining the fastening function with the contamination prevention function in a single integrated structure rather than adding separate components.
Solution Approach 2:
The recesses generate secondary flows that automatically prevent contamination accumulation without requiring external cleaning systems or additional active components. The structure serves itself by using the rotational flow to keep the gap region clean, eliminating the need for separate maintenance mechanisms.
3Object-affected harmful factors
If hub body is closed with cover, then contamination resistance is improved, but ease of maintenance deteriorates
Solution Approach 1:
The hub body is designed with a cover that can be removed to provide access for maintenance, while the recesses and secondary flows provide preliminary protection against contamination during normal operation. This allows the system to maintain contamination resistance during operation while enabling easy maintenance when needed.
Solution Approach 2:
The cover design allows the hub body to transition between a closed state during operation (providing contamination resistance) and an open state during maintenance (providing ease of access). This dynamic configuration enables the system to switch between protection and maintenance modes as needed.
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
Reduces contamination, enhances efficiency, and simplifies maintenance by minimizing dirt accumulation and facilitating easy assembly and disassembly.
Implementation Method 1
The recess furthermore generates secondary flows or eddies which suppress the adhesion of dirt in the gap region.
Data Source
AI summary
A stirrer arrangement including a shaft, a drive device, a hub body, and at least two blades. The at least two blades are arranged on the hub body and extend radially from the hub body relative to the rotational axis. Each of the at least two blades has a foot that is configured to fasten on the hub body and, along a radial extent, a leading-edge region and a trailing-edge region opposite the leading-edge region. The hub body has a wall in which depressions are provided to receive the blade feet. On an outside of the wall, recesses are provided which reach up to a part portion of the depressions. In a vicinity of the foot, each blade has an extent which protrudes beyond the foot, is formed by the leading-edge region and protrudes into the respective recess.