Coaxial Flow and Shearing Impellers for High Viscosity Mixing
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Solution Overview
Problem
Conventional stirring devices face difficulties in maintaining fluidity and preventing idle rotation of high-speed stirring impellers due to the creation of voids around shearing teeth, especially when dealing with high viscosity or thixotropic fluids, as they lack a structured relationship between the ribbon-shaped and high-speed rotation impellers.
Innovation Solution
A stirring device with a circular cross-sectional tank featuring a flow impeller and shearing impeller that are coaxially rotatable, where the flow impeller generates an induced flow directed towards the lower side, and the shearing impeller is positioned to receive this flow, ensuring continuous supply of the stirring object and preventing void formation, even at high rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high-speed rotation stirring impeller is used to shear the stirring object, then the shearing efficiency is improved, but a space (hollow space) with no stirring object is created around the shearing teeth causing the impeller to run idle
Solution Approach 1:
The ribbon-shaped stirring impeller performs preliminary action by pumping the stirring object toward the shearing teeth of the high-speed rotation stirring impeller before the shearing action occurs. This preliminary pumping action ensures that the stirring object is continuously supplied to the shearing zone, preventing the creation of hollow spaces and idle rotation of the high-speed impeller.
Solution Approach 2:
The ribbon-shaped stirring impeller acts as an intermediary between the bulk stirring object and the shearing teeth. It mediates the transport of the stirring object to the shearing zone, ensuring continuous supply and maintaining reliable operation of the high-speed rotation stirring impeller without direct exposure to the bulk material flow issues.
2Speed
If the high-speed stirring impeller rotates at a higher speed, then the shearing capability is improved, but the phenomenon of causing difficulty in shearing due to space formation around the impeller occurs more easily
Solution Approach 1:
The ribbon-shaped stirring impeller performs preliminary pumping action to supply the stirring object to the high-speed rotation stirring impeller before shearing occurs. This ensures that even at higher rotation speeds, the shearing impeller continuously encounters stirring object material, preventing space formation and maintaining stable shearing performance.
3Device complexity
If the ribbon-shaped stirring impeller and the high-speed rotation stirring impeller are arranged in random manner, then the device complexity is reduced, but the stirring object cannot flow into the area with stirring object pumped out causing void formation
Solution Approach 1:
The impellers are arranged with specific local quality requirements: the ribbon-shaped stirring impeller is positioned to pump the stirring object toward the shearing teeth of the high-speed rotation stirring impeller. This localized arrangement ensures proper flow direction and continuous material supply to the shearing zone, maintaining fluidity and preventing void formation.
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 configuration ensures effective shearing and mixing of high viscosity and thixotropic fluids, preventing idle rotation of the shearing impeller and maintaining efficient stirring performance, suitable for emulsification and handling fluids with viscosities up to 100,000 cP or more.
Implementation Method 1
the flow impeller rotates around a vertical axis to form at least a flow directed toward a lower side in a stirring object existing in the stirred tank
Implementation Method 2
the shearing impeller imparts a shearing force to the stirring object by rotation
Data Source
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AI summary
Provided is a stirring device for stirring a stirring object having fluidity including: a stirred tank, of which an inner peripheral wall has a circular shape in cross section; and at least one flow impeller and at least one shearing impeller that are located inside the stirred tank and configured to be rotatable independently of each other, in which rotational centers of the flow impeller and the shearing impeller are coaxially provided, the flow impeller rotates around a vertical axis along the inner peripheral wall of the stirred tank to form at least a flow directed toward a lower side in the stirring object existing in the stirred tank, and the shearing impeller imparts a shearing force to the stirring object and is provided on a radially inward side of the flow impeller in the stirred tank and at a position contacting the flow of the stirring object formed by the flow impeller.