Northvale Korting Fluid Jet Theory and Applications of Eductors By Patrick Belcher

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

Eductor Basics.-2 The motive fluid enters the nozzle and is sent into the suction chamber as a high velocity, low pressure jet. This generates a low pressure area in the chamber.

Eductor Basics.-3 The low pressure area entrains or draws in the suction fluid. Both streams are thoroughly mixed within the turbulent area of the diffuser throat.

Eductor Basics.-4 In the outlet cone of the diffuser, the velocity of the mixed stream is converted back to pressure energy This enables the eductor to overcome a discharge head which is higher than the suction head but lower than the motive pressure.

Pumping Maximum lift 8mwg Lift affected by specific Gravity Performance is dependent on motive water pressure and flow rate.

Vacuum Producing Liquid or gas Liquid or gas Used for pump priming Used for pump priming Vessel evacuation Vessel evacuation Fume Extraction Fume Extraction

Aeration 1 Adds compressed air to water Small bubbles promote solubility Mixing throat increases intimacy between air & fluid

Aeration 2 Uses atmospheric air. Mixes tank contents Aids flocculation

Mixing 1 Standard mixing application. 3:1 mixing No. of nozzles and orientation depending on tank shape.

Dilution 1 Can dilute and lift at the same time. Control dilution using suction valve. Risk of backflow if discharge pressure too high. PTFE lined option

Dilution 2 Scheme for high dilution ratios. Around the pump loop. Uses the pressure differential between inlet & outlet of pump. Does not create a permanent pressure loss in the pump discharge line. Can be isolated when not required. Additional mixing created by pump action.

Hopper Eductor Used to introduce powders in to liquid stream To make lime solution.

Eductor Benefits No moving parts. No moving parts. –Minimal Maintenance –Use in restricted space –Suitable for hazardous zones Can run with no suction flow, or with entrained solids. Can run with no suction flow, or with entrained solids. Self Priming Self Priming –Ideal for intermittent use Available in virtually all materials –Carbon Steel –Stainless /316/304/Duplex –PTFE lined pipe –Poly Propylene –UPVC –ABS –Hastelloy

Design Considerations. High backpressure a problem => Backflow to suction branch. High backpressure a problem => Backflow to suction branch. Requires a high pressure drop - Typical discharge pressure < 0.5 Motive pressure. Requires a high pressure drop - Typical discharge pressure < 0.5 Motive pressure. Best designed for single motive operating point. Adjust mixture by suction, not by motive Best designed for single motive operating point. Adjust mixture by suction, not by motive Flow from bottom of tank could be of benefit. Flow from bottom of tank could be of benefit.

Eductor Uses GAC/ Sand/Resin removal. GAC/ Sand/Resin removal. Dilution Dilution –Suction of concentrates »Sulphuric Acid »Caustic »Brine »Citric Acid »Orthophosphoric acid »Anti foaming agent »Hypochlorite solution Dissolved air flotation Pumping –Emptying pits and bunds Tank mixing System priming