Mixing Technology represents a balance between the requirements of the process and the output efficiency of the impeller.
Impellers used in agitation systems are required to produce three basic fluid regimes:
Or a combination of these 3
Agitator impellers all obey the relationship
P = Q x H (where Q = Flow and H = Head (Shear)
Thus, all impellers are selected for their ability to produce various combinations of the variables of Power, Flow and Head (Shear).
The main impellers used by AFROMIX in the selection and manufacture of their high technology agitators are:
AFROMIX Type F3 impeller for high flow production
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This 3 bladed, high efficiency impeller is specifically designed to produce high flow velocity at low installed power. These low solidity impellers are usually selected for the following duties:
Leaching , CIP, Neutralisation, Lime Make and Storage, Water Treatment, Chemical Reaction, Pulp Mixing, Flocculation, and similar applications where the generation of flow drives the agitator selection.
AFROMIX Type P4 Pressure Impeller for Gas dispersion.
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These 4 bladed, high solidity impellers are specifically designed for applications involving the introduction of high volumes of gas. With a solidity ratio of greater than 90%, the gas introduced is unable to bypass the impeller. This results in an increase of power under gassed conditions (unlike 6 bladed Rushton impellers which reduce in power under gassed conditions), eliminating the need for variable speed or 2 speed motors to allow for the increased power when gas is reduced or shut down.These high efficiency axial gas dispersions are normally used on the following processes :-
High pressure autoclaves
Fermentation and Hydrogenation
AFROMIX Type P 3 impeller for High viscosity applications
P328 IMPELLERIn high viscosity applications, there is a need for an impeller to produce flow in viscous, low Reynolds number fluids. Normal low solidity impellers do not produce macro flow and high solidity impellers draw excess power. The compromise is the AFROMIX P3 impeller. This 3 bladed impeller has a solidity ratio of approximately 70%, allowing the production of macro flow in duties with a Reynolds number of 200-300, or effective maximum viscosity of 40 000cps.
These impellers bridge the gap between low solidity aerofoils, and close clearance impellers like gates, spirals and anchors, which would have, traditionally, been used for applications in excess of 15000cps.
The AFROMIX FS 4 impeller
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The AFROMIX FS4 impeller is used extensively for applications requiring high flow. however,despite its high efficiency,its limitations are its inability to produce sufficient shear for applications other than its designed purpose.
PxQxH-Where Q = Flow and H=Head(shear)
So, impellers producing high flow(Q), provide reduced Shear(S). For these applications,the tried and tested Pitched Blade impeller still has advantages,despite its relatively high power draw and low efficiency. This standard impeller,usually pitched at 45° or a convenient angle,is named the AFROMIX FS 4. Whilst rarely used it is still an important weapon in the mixing artillery.
The AFROMIX R6 impeller pump mixer
Afromix impellerEquipment0 new logoThe AFROMIX R6 radial flow impeller is a unique impeller designed for pump mixer applications such as solvent extraction or thickener dilution systems.
The impeller is designed to advance flow, maximise dispersion and provide specified head generation. These curved blade pump turbines offer maximized head and flow while reducing power consumption, minimum shear generation and turbulence.