Agitator shafts

Stokes Vacuum, Inc. Prices include shell, 50-lh/in -gaiige jacket, agitator, drive, and motor auxiliary dust collectors, condensers. iLoading with product level on or around the agitator shaft. 

Pitched-blade turbines (Fig, 18-3) are used on top-entering agitator shafts instead of propellers when a high axial circulation rate is desired and the power consumption is more than 2,2 kW (3 hp), A pitched-blade turbine near the upper surface of liquid in a essel is effecth e for rapid submergence of floating particulate solids,... 

High temperature due to excessive agitator shaft work resulting in high reaction rates. 

The conjoint action of a tensile stress and a specific corrodent on a material results in stress corrosion cracking (SCC) if the conditions are sufficiently severe. The tensile stress can be the residual stress in a fabricated structure, the hoop stress in a pipe containing fluid at pressures above ambient or in a vessel by virtue of the internal hydraulic pressure created by the weight of its contents. Stresses result from thermal expansion effects, the torsional stresses on a pump or agitator shaft and many more causes. 

The agitator shaft is inclined from 0 to 45 with the vertical, and multiple impellers are used with longer reactors. 

The first-stage CSTR is completely filled and utilizes a pair of opposing axial flow turbines on the agitator shaft. The maximum recommended viscosity for this reactor is 40 poise and the turbine agitation is set such that total flow volume generated per unit time by the turbines is 500 to 1000 times the feed rate to the reactor. 

If turbine or marine propeller agitators are used to mix relatively low viscosity liquids in unbaffled tanks, vortexing develops. In this case the liquid level falls in the immediate vicinity of the agitator shaft. Vortexing increases with rotational speed N until eventually the vortex passes through the agitator. As the liquid viscosity increases, the need for baffles to reduce vortexing decreases. 

Propeller A propeller is a three- or four-bladed flow impeller, having helically shaped blades. The flow is primarily axial (discharge flow parallel to the agitator shaft) and is most effective in low-viscosity fluids. The marine-type propeller (Figure 3.15) is characteristically operated at relatively high speed, particularly in low-viscosity liquids (Treybal, 1980). 

Example 10.2 compares data of Table 10.4 with calculations based on Figures 10.6 and 10.7 for all-liquid mixing. Power and rpm requirements at a given superficial liquid velocity are seen to be very sensitive to impeller diameter. When alternate combinations of HP/rpm are shown in the table for a particular performance, the design of the agitator shaft may be a discriminant between them. The shaft must allow for the torque and bending moment caused by the hydraulic forces acting on the impeller and shaft. Also, the... 

The particle size of the precleaned coals was reduced to mean diameters near 10 jum by milling in a stirred-ball slurry attritor mill. Slurries containing 20% by weight coal dispersed in deionized water were milled for 2 minutes using 6.3 mm diameter stainless steel media (140 cc slurry/kg media) and an agitator shaft speed of 290 rpm (18). The slurries were then filtered and dried in a recirculating nitrogen atmosphere at 110°C for 3 hours. 

O-ring agitator shaft seals in an oxidation reactor operating at temperatures above 220°C (428°F) and in contact with 70% acetic acid... 

Fig. 14. Reactor of the continuous organomagnesium synthesis of organoethoxysi-lanes 1 - cooling jacket 2 - rake element 3 - choke for loading off the products of the reaction 4 - choke for loading magnesium 5 - agitator shaft 6 - separator 7 -spiral (hollow pipe) 8 - thermocouple pocket 9 - choke for loading the reactive mixture 10 - casing of the reactor...

Starch is dispersed in the paper mill in large stainless steel tanks by injection of steam or by heat transfer from a steam-heated jacket. The tanks are stirred and equipped with baffles to prevent formation of a single vortex at the agitator shaft. A minimum heating time of 20 minutes at 95°C is normally required. Steam injection dilutes the starch paste by condensate, which must be considered for concentration control. Pastes that are prone to retrogradation are held at a temperature above 91°C or quickly cooled to 66°C to prevent amylose formation. Attention to storage temperature and water balance is an essential requirement for the effective use of starch in a paper mill. 

Fig. 1. Schematic diagram of a centrifugal impeller bioreactor (5 1). 1 Magnetic stirring device 2 gas in 3 head plate 4 agitator shaft 5 measurements of the liquid velocity profiles of the discharge flow were performed in the vertical direction across the width of the blades (the vertical dashed line) and at various radial distances from the impeller tip 6 sintered stainless sparger 7 centrifugal blade 8 draft tube 9 DO probe 10 centrifugal rotating pan...

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