Northvale Korting Fluid JetNorthvale Korting Fluid Jet

Theory and Applications of EductorsTheory and Applications of Eductors

ByBy

Patrick Belcher Patrick Belcher

Eductor Basics.-1Eductor Basics.-1

Pressurised liquid is fed, at normal pipeline Pressurised liquid is fed, at normal pipeline velocity, into the velocity, into the motive fluidmotive fluid connection. 1 connection. 1

Eductor Basics.-2Eductor Basics.-2 The motive fluid enters the nozzle and is sent into the The motive fluid enters the nozzle and is sent into the

suction chamber as a high velocity, low pressure jet.suction chamber as a high velocity, low pressure jet.

This generates a low pressure area in the chamber.This generates a low pressure area in the chamber.

Eductor Basics.-3Eductor Basics.-3

The low pressure area entrains or draws in the The low pressure area entrains or draws in the suction fluid.suction fluid.

Both streams are thoroughly mixed within the Both streams are thoroughly mixed within the turbulent area of the diffuser throat.turbulent area of the diffuser throat.

Eductor Basics.-4Eductor Basics.-4

In the outlet cone of the diffuser, the velocity of the mixed In the outlet cone of the diffuser, the velocity of the mixed stream is converted back to pressure energystream is converted back to pressure energy

This enables the eductor to overcome a discharge head This enables the eductor to overcome a discharge head which is higher than the suction head but lower than the which is higher than the suction head but lower than the motive pressure.motive pressure.

Pumping Pumping

Maximum lift 8mwgMaximum lift 8mwg Lift affected by Lift affected by

specific Gravityspecific Gravity Performance is Performance is

dependent on motive dependent on motive water pressure and water pressure and flow rate.flow rate.

Vacuum ProducingVacuum Producing

Liquid or gasLiquid or gas Used for pump primingUsed for pump priming Vessel evacuationVessel evacuation Fume ExtractionFume Extraction

Aeration 1Aeration 1

Adds compressed air to waterAdds compressed air to water Small bubbles promote solubilitySmall bubbles promote solubility Mixing throat increases intimacy between air Mixing throat increases intimacy between air

& fluid& fluid

Aeration 2Aeration 2

Uses atmospheric air.Uses atmospheric air. Mixes tank contentsMixes tank contents Aids flocculationAids flocculation

Mixing 1Mixing 1

Standard mixing Standard mixing application.application.

3:1 mixing3:1 mixing No. of nozzles and No. of nozzles and

orientation depending orientation depending on tank shape.on tank shape.

Dilution 1Dilution 1

Can dilute and lift at Can dilute and lift at the same time.the same time.

Control dilution using Control dilution using suction valve.suction valve.

Risk of backflow if Risk of backflow if discharge pressure too discharge pressure too high.high.

PTFE lined optionPTFE lined option

Dilution 2Dilution 2

Scheme for high dilution ratios.Scheme for high dilution ratios. Around the pump loop. Uses the pressure differential between inlet & outlet of Around the pump loop. Uses the pressure differential between inlet & outlet of

pump.pump. Does not create a permanent pressure loss in the pump discharge line. Can be Does not create a permanent pressure loss in the pump discharge line. Can be

isolated when not required.isolated when not required. Additional mixing created by pump action.Additional mixing created by pump action.

Hopper EductorHopper Eductor

Used to Used to introduce introduce powders in powders in to liquid to liquid streamstream

To make To make lime lime solution.solution.

Eductor BenefitsEductor Benefits

No moving parts.No moving parts.– Minimal MaintenanceMinimal Maintenance– Use in restricted spaceUse in restricted space– Suitable for hazardous Suitable for hazardous

zoneszones Can run with no Can run with no

suction flow, or with suction flow, or with entrained solids.entrained solids.

Self PrimingSelf Priming– Ideal for intermittent Ideal for intermittent

useuse

Available in virtually Available in virtually all materialsall materials– Carbon SteelCarbon Steel

– Stainless Stainless /316/304/Duplex/316/304/Duplex

– PTFE lined pipePTFE lined pipe

– Poly PropylenePoly Propylene

– UPVCUPVC

– ABSABS

– HastelloyHastelloy

Design Considerations.Design Considerations.

High backpressure a problem => Backflow High backpressure a problem => Backflow to suction branch.to suction branch.

Requires a high pressure drop - Typical Requires a high pressure drop - Typical discharge pressure < 0.5 Motive pressure.discharge pressure < 0.5 Motive pressure.

Best designed for single motive operating Best designed for single motive operating point. Adjust mixture by suction, not by point. Adjust mixture by suction, not by motivemotive

Flow from bottom of tank could be of Flow from bottom of tank could be of benefit.benefit.

Eductor UsesEductor Uses

GAC/ Sand/Resin GAC/ Sand/Resin removal.removal.

DilutionDilution– Suction of concentratesSuction of concentrates

» Sulphuric AcidSulphuric Acid

» CausticCaustic

» BrineBrine

» Citric AcidCitric Acid

» Orthophosphoric acidOrthophosphoric acid

» Anti foaming agentAnti foaming agent

» Hypochlorite solutionHypochlorite solution

Dissolved air flotationDissolved air flotation PumpingPumping

– Emptying pits and bundsEmptying pits and bunds

Tank mixingTank mixing System primingSystem priming