Planetary Mixing Mechanism for Small-Batch Viscous Materials
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Solution Overview
Problem
Existing mixing apparatuses are inadequate for handling highly viscous materials, such as bone cement, which experience increased viscosity during polymerization, requiring higher shear forces that traditional equipment cannot provide, especially when mixing small batches with rapid viscosity increases.
Innovation Solution
A mixing apparatus featuring a stationary circumferential gear driving a planetary mixing element that rotates and revolves around a central mixing element, with a gear ratio and surface design to generate sufficient shear force, along with a wiping element for efficient material transfer and removal, allowing for effective mixing of materials with viscosities up to 500 Pascal/seconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional mixing apparatus is used for highly viscous materials, then the mixing capability is insufficient, but the device complexity is low
Solution Approach 1:
The mixing apparatus is divided into a stationary circumferential gear component and a planetary mixing element component. The planetary mixing element combines multiple mixing actions (rotation around its own axis and revolution around the central mixing element) to provide enhanced mixing capability for highly viscous materials without requiring a completely complex device design
Solution Approach 2:
The planetary mixing element dynamically combines two types of motion: rotation about its own axis and revolution around the central mixing element. This dynamic movement pattern creates variable shear forces throughout the mixing well, effectively handling highly viscous materials while maintaining a relatively simple mechanical structure
2Manufacturing precision
If mixing time is extended to achieve desired viscosity, then the mixing completeness improves, but the productivity decreases
Solution Approach 1:
The planetary mixing element continuously engages with the mixture throughout its orbital path around the central mixing element, ensuring that all portions of the mixture receive consistent mixing action. This continuous useful action achieves complete mixing in shorter time, maintaining productivity while ensuring manufacturing precision
Solution Approach 2:
The planetary mixing element performs periodic mixing cycles as it revolves around the central mixing element, creating repeated shear and folding actions that rapidly homogenize the mixture. This periodic action accelerates the mixing process while maintaining completeness
3Reliability
If shear force is increased to handle high viscosity, then the mixing effectiveness improves, but the energy consumption increases
Solution Approach 1:
The planetary mixing element follows a curved orbital path around the central mixing element, creating efficient shear flow patterns. The curved motion generates natural convection and folding of the material, achieving effective mixing with reduced energy input compared to linear or reciprocating motions
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 apparatus efficiently mixes highly viscous materials by generating the necessary shear forces to achieve desired viscosities within short times, ensuring complete mixing and effective transfer of bone cement, even in small batches, with the wiping element ensuring material retention and easy removal.
Implementation Method 1
A mixing apparatus featuring a stationary circumferential gear driving a planetary mixing element that rotates and revolves around a central mixing element, with a gear ratio and surface design to generate sufficient shear force
Data Source
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AI summary
A drive mechanism for a mixing apparatus is disclosed. The drive mechanism comprises a) a set of teeth (254) defining a circular path on an inner circumference of a vessel (252) characterized by an internal volume not exceeding 100 ml; b) a toothed wheel (270) characterized by an axis, the wheel adapted to engage said set of teeth and to rotate about the axis; and c) an actuator adapted to provide a force which causes the toothed wheel to advance along the circular path. A method of mixing components of a viscous mixture is also disclosed. The method comprises a) placing the components in a mixing well characterized by an inner volume of not more than 100 ml; b) deploying at least one planetary mixing element and a central mixing element in the mixing well; and c) operating a manual drive mechanism to cause the planetary mixing element to both rotate about its own axis and revolve around the central mixing element in order to mix the components to form a mixture.