Impeller Technology - AxFlow

1 The Leader in Mixing TechnologyImpeller TechnologyThe key to an efficient mixing sys-tem is the Impeller . For eachapplication there is an idealimpeller. Lightnin, with over 70years experience in fluid mixing,are uniquely placed to offer effec-tive solutions for all s commitment toresearch and development hashelped to create a unique, mod-ern, spectrum of impellers, whichmeet the needs of processesaccurately and s mixers range from fractional kW through to theworld s largest unit at over2500kW. The use of Lightninimpellers has generated lowercapital and operating costs for many thousands of our customers world and DevelopmentThe Key to Successful Impeller DesignThe LIGHTNIN Laser laboratoryLightnin operates the world's mostadvanced mixing laboratory. Usingthe four laser beams of a LaserDoppler Velocimeter (LDV) fluidmotion as pumping capacity and -direction at any point of a vessel are converted into digital information vital to Impeller designand A6000 Impeller operating in the laser laboratoryFinite Element AnalysisLightnin complement researchinto fluid dynamics and impellerdesign by employing advancedcomputational techniques in theform of (Finite Element Analysis -FEA).

2 FEA is used principally intwo areas: Modal Analysis. The naturalfrequencies of the mixer andits mounting structure can bepredicted, thus ensuring thatpotential costly vibration problems are eliminated at thedesign stage. Optimising agitator mechanicaland structural integrity, withoutunnecessary overdesign, thusensuring customers receive themost cost effective mixingsolutions for their Fluid MixingThese accurate data from the LDVare combined with the power of"Computational-Fluid-Dynamics"-Program ms (CFD) in order to predict the mixing dynamics inlarge tanks with unusual geometryor specific process powerful capabilityreduces substantially pilot- or fullscale plots graphically display full scale mixer performanceFinite element analysis of high efficiencyimpeller bladeImpeller type:A310 - A510 Low viscosity and flow-controlled applicationsThe A310 - A510 series provides acombination of performance char-acteristics and high flow efficiencynot available from other types ofaxial flow impellersThe A310 - A510 can produce thesame flow and process results at alower power than other axial flowimpellers thus reducing operatingand capital type: C100 - C110 Draft-tube specifically for depend-able draft tube service, the C100 - C110 has a true airfoilshape and provides high flow, evenin unstable process conditions,whilst minimising power require-ments.

3 A specific family of impellers(unique to Lightnin) based upon theC100 - C110 design is available foruse in draft include alumina, gold,uranium and type: A200 Low/medium viscosity, flow-controlled traditional Impeller for largervolume applications . Largelysuperceded by the A510, it still hasa specific role in applications wherea degree of fluid shear is beneficialto the overall process Type: A340 Gas/ liquid applications with up-pumping characteristicsThe A340 with up-pumping axialflow is the most recent developmentfor gas/liquid applications . The A340 can be used for coalescing and non-coalescing systems and allows better mass transfer heat transfer shorter mixing timesUnique Impeller Range for accurate, Impeller type:A6000 Low viscosity flow-controlledapplications for hostile A6000 is a composite con-struction Impeller . It uses a highgrade vinyl ester resin system withstrength and corrosion resistancebeing key exotic metals such as titanium, zirconium, hastelloy, required, the A6000 can be acost effective alternative.

4 Due to theoptimum airfoil profile produced byimpact moulding production techniques, the A6000 is 25% moreefficient than the type: A315 Axial flow Impeller for gas/liquid applicationsThe A315 is capable of dispersinggas and controlling flow patterns atsignificantly higher gas rates thanother axial flow to conventional Rushtontype radial flow turbines, the A315can provide up to 30% greater masstransfer at equal torque and axial flow patterns from theA315 give good solids suspensionand significantly reduce type:A312 Axial flow Impeller for sideentry applicationsThe A312 is designed for the arduous requirements of pulp andpaper is also used in other side entryapplications such as oil storage andFGD (Flue Gas Desulphurisation). Itis an axial flow Impeller with a minimal radial flow component,unlike other conventional side entrymixer type:R400 Two bladed anchor for higherviscosity R400 is a contoured two blad-ed anchor.

5 It has applications inblending and particularly, heat trans-fer, where the viscosities range from10000 to 100000 centipoise. Impeller type:R100 - R130 High shear mixing and gas-liquid R100 rushton turbine is the traditional Impeller for gas - liquidmass transfer controlled systems. Itis also used where higher shear R130 shown above has similarcharacteristics to the R100 but gives: A higher power input in thegassed condition (reduced K factor effect) Lower power in the ungassedconditionImpeller type:R500 (SAW Tooth)High shear, typically used fordifficult to disperse R500 provides high shear is generally used in conjunctionwith a high flow Impeller in appli-cations involving a combination ofblending and a need for physicalchange created by fluid type:A400 Helical Impeller for high viscosity very high viscosity (above100,000 centipoise) is involved, helical impellers can be used. A variety of options in terms of number of flights, pitch and helix are available to suit the specificrequirements of the A400 also promotes surfacerenewal and heat type:A320 High flow Impeller for higherviscosity A320 is designed to operate inhigher viscosity fluids.

6 The effective-ness of many high efficiency impellersystems which are designed tooperate in the turbulent flow regimeis impaired as the viscosity of thefluid increases and the ReynoldsNumber decreases. This is not thecase with the A320. The uniquedesign of the Impeller reduces bothcapital and operating costs. Blendtimes are also reduced compared toother open impellers used at lowReynolds resultsImpeller SelectionMixing is the key to process design. Impeller selection is a key to impellers convert energy into fluid motion is fundamental to theirability to provide a predictable process the energy (P)applied by any mixing Impeller produces a pumpingeffect (Q)and a velocity head (H), so thatPaQHA knowledge of how this balance of energy distribution can change withimpeller geometry is fundamental to mixer design. Lightnin has used itsextensive knowledge of Impeller fluid mechanics to develop a family ofefficient, process specific, ComparisonBasic formularNot all impellers perform at a similar level of efficiency even though they may super-ficially look to be similar in design.

7 The performance capability of flow impellers can be compared by an evaluation of knowledge of the flow numbers (Nq) andpower number (Np) of the impellers beingcompared is Technology provides predictable mixingNq=QND3 Nre=ND2rmNp= Impeller power numberNq= Impeller flow numberN= Impeller rotational speed (1/sec)Nre= Impeller Reynolds Numbermmmm=Viscosity in PasP= Impeller power (W)D= Impeller diameter (m)Q= Impeller primary flow(m3/sec) (pumping capacity)r=Fluid density (kg/m3)The following basic equationscan then be applied: Impeller spectrum indicates relative powerapportioned to Qand Hfor various SpectrumA6000A310 - A510C100 - C110A320A312A315A200R100R500kWFlow(Q)Pre ssureHead (Shear)HComparison BasisBefore two impellers can be compared, a basis for the comparison must be many combinations of parameters can be applied ( power required at constant flow and speed, orconstant speed and diameter), the most applicable to the flow controlled operations of blending, solids sus-pension and heat transfer is constant diameter, Dand constant flow, Q.

8 Applying the basic mixing formulae inratio form gives the following comparisonTable 2 demonstrates that at constant Impeller diameter to tank diameter ratio (D/T)and constant flow Q( process result), the Lightnin A510 mixer requires 51% less power and less than half the torque (andtherefore lower operating costs), than a mixer fitted with a pitched blade the formulare intable 1, the performanceof different impellers canbe evaluated in relation toeach other. For example,table 2 compares theLightnin A510 with a 45 Pitched Blade 1 Table 2 ParameterRatioSpeedNq (2)Nq (1) (Nq2)3Np2 (Nq1)3 Flow/PowerNp2 (Nq1)3Np1 (Nq2)3 TorqueNp1 (Nq2)2Np2 (Nq1)2 ParameterLightninPitched A310blade E 0502 Bran+Luebbe GmbH 13 60 D-22803 Norderstedt Phone (040) 522 02-0 Fax (040) 522 02 444 E-Mail Internet OrganisationQualityWe recognize that our customers demand a highquality product manufactured and serviced in a timelyand efficient manner.

9 Working within the processindustry we are fully aware of the specific demandsfor quality standards and all our companies are ISO 9001 our products are built to last and we provide warranty periods that are appropriate for the specificindustries where the equipment is to contact usYour local contactWorldwide SupportCombining Bran+Luebbe, Lightnin, Plenty and Premier Mill has lead to a worldwide network ofexpertise in process equipment for industrial mixingand metering. With our own companies and representatives you will always find experiencedsupport immediately Sales and ServiceOur dedicated direct service teams are readily avail-able to support your process equipment at all spares and service solutions can be obtainedfrom all our companies and ensure operating capacityof your valuable production