Agitation fluid jets

Despite the several systems disclosed, garments agitation is substantially operated in two ways, with a rotating basket or by fluid-jets. In the former, the mechanical force necessary to... 

Agitated and jet mixed vessels are used for blending duties. The choice of equipment will depend on the viscosity of the fluid, the desired blend time, and the size of the vessel. The chapter is divided into four sections that cover design rules for ... 

The commonly used types of mixing equipment can be placed in the broad categories (1) mechanical agitators, (2) inline motionless mixers, (3) tank jet mixers, and (4) miscellaneous. The nature and type of agitator used depends upon the scale and type of mixing and upon the fluids being mixed. The broad classes of impellers are ... 

Baker and Walter report tests performed on open jacketed agitated vessels and published some of the limited results for this type of equipment. These data indicate the effects of jetting the fluid at various velocities into the jacket. 

Dimoplon, W. (1978) Hyd. Proc. 57 (May) 221. What process engineers need to know about compressors. Fischer, R. (1965) Chem. Eng., NYT2 (Sept. 13th) 179. Agitated evaporators, Part 2, equipment and economics. Fossett, H. and Prosser, L. E. (1949) Proc. Inst. Mech. Eng. 160, 224. The application of free jets to the mixing of fluids in tanks. 

To remove solids from any vessel provided with built-in sand jets, sand drains are opened in a controlled manner and high-pressure fluid (usually produced water) is pumped through jets to agitate the solids and flush them away, jets are normally designed with a 20-fps jet tip velocity and are aimed to give good coverage of the vessel bottom. 

Installation of agitating nozzles is recommended if sensible liquid heating or cooling is to be used with plain jackets. Nozzles produce liquid jets directing the inlet jacket fluid in a spiral fashion into the jacket. This increases the effective velocity and turbulence level. Vendors have information dealing with their performance and installation. 

Fluid viscosity and volume to be mixed are the most significant factors. Propellers viscosity <3000 mPa-s volumes <750 m Turbines and paddles viscosity <50,000 mPa-s volumes <75 m Liquid jets viscosity <1000 mPa s volumes >750 m Air agitation viscosity <1000 mPa-s volumes >750 mT Anchors viscosity <100,000 mPa-s Re <10,000 volumes <30 mT Kneaders viscosity 4,000 to 1.5 x 10 mPa s volumes 3 to 75 m Roll mills viscosity 10 to 200,000 mPa s volumes 60 to 450 m For viscosity >10 consider extruders, Banbury mixers, and kneaders. Paddle reel/stator-rotor gentle mechanical mixing for coagulation, viscosity <20 mPa s volumes large. Motionless mixers viscosity ratio <100,000 1 continuous and constant flow rates residence times <30 min and flow rate ratio of <100 1. Other related sections are size reduction (Sections 16.11.8.1 and 16.11.8.3), reactors (Section 16.11.6.10), and heat transfer (Section 16.11.3.5). 

Note that the above power values are for power dissipated by the jet or propeller and do not include motor efficiency and bearing losses for the agitator, or pump efficiency and external pipe friction losses for the jet. The head loss by the recirculating fluid in a jet mixer can be significant proportion of the total fluid head required for mixing. 

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