The specifications and types of the stirring paddles of Overhead stirrers are diverse. Their design should be selected based on the properties of the material (such as viscosity, density, whether it contains solid particles, etc.) and the mixing requirements (such as uniformity, dissolution rate, gas dispersion, etc.). The following are the common types and specifications of stirring paddles:
Paddle Blade
Features: The blades are flat, fan-shaped or rectangular, suitable for the mixing of low-viscosity liquids (such as aqueous solutions), with low shear force, avoiding damage to the material structure.
Specification
The diameter is usually 1/3 to 2/3 of the container's diameter.
Number of blades: 2 to 4, and the installation Angle is adjustable.
Material: Stainless steel (such as 316L), aluminum alloy or polytetrafluoroethylene (corrosion-resistant).
Applicable scenarios: Food flavoring, coating mixing, suspension preparation.
2. Turbine Stirring paddle (Rushton Turbine
Features: The blades are disc-shaped, with radial or inclined blades, suitable for medium and high viscosity liquids or scenarios requiring strong shear force (such as emulsification and dissolution).
Specification
It has a relatively small diameter (1/4 to 1/3 of the container's diameter), with 4 to 6 blades.
The rotational speed is relatively high (usually 300 to 1500 rpm).
Material: Stainless steel or special coating (anti-corrosion).
Applicable scenarios: Laboratory reactions, cosmetic emulsification, and drug mixing.
3. Anchor Blade
Features: U-shaped or frame-shaped structure, close to the container wall, suitable for slow mixing of high-viscosity materials (such as adhesives, pastes), avoiding air entrapment.
Specification
The width is close to the inner diameter of the container, and the height is level with the liquid surface.
Material: Heavy stainless steel (enhanced rigidity).
Applicable scenarios: Polymer processing, food processing (such as dough mixing).
4. Propeller type stirring paddle (Propeller
Features: Similar to Marine propellers, the blades are inclined to generate axial flow, making it suitable for large-volume mixing of medium and low viscosity liquids.
Specification
It has a relatively large diameter (1/2 to 3/4 of the container's diameter), with 2 to 3 blades.
The rotational speed is relatively low (100 to 500 rpm).
Applicable scenarios: Large-scale solution mixing, wastewater treatment.
5. Dissolution Disc
Features: Disc-shaped with serrated edges, high-speed rotation generates strong shearing force, used for the rapid dispersion and dissolution of solid powders.
Specification
It has a relatively small diameter and can reach a rotational speed of 3000 rpm.
Material: Hardened stainless steel or ceramic coating.
Applicable scenarios: Dye dissolution, food additive mixing.
6. Special types
Multi-head propeller: Multi-layer blade design enhances mixing efficiency and is suitable for high-viscosity or solid particle-containing materials.
Adjustable blade paddle: The Angle or position of the blades can be adjusted to flexibly adapt to different process requirements.
Scraping wall-type stirring paddle: With scrapers on the edge to prevent material from adhering to the container wall, it is often used for high-viscosity or viscoelastic fluids.
Selection basis
Material viscosity: For low viscosity, select turbine type/paddle type; for high viscosity, choose anchor type/propeller type.
Container size: It is recommended that the diameter of the impeller be 1/3 to 2/3 of the container diameter.
Mixing purpose: Dissolve with a dissolving disc, emulsify with a turbine, and mix evenly with a paddle.
Hygiene requirements: Food or medicine should be made of materials that are easy to clean and have no dead corners (such as 316L stainless steel).
It is recommended to determine the optimal paddle type and parameters (such as rotational speed and diameter ratio) of the stirring paddle through experiments based on specific process requirements.
