Turbine impeller

Howe er, most conventional pump impellers receive the fluid into the impeller eye, at the center or inside diameter of the impeller. There are single suction impellers, and dual or double suction impellers with two eyes, one on each side. Dual suction impellers are mostly specified for low NPSH applications because the eye area is doubled (it ean reeeive twice as much fluid at a lower velocity head). Dual suction impellers arc mostly found on split case pumps where the shaft passes completely through the impeller. But they can afso be found mounted onto the end of the shaft in some special pump designs. 

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Commonly used heat-transfer surfaces are internal coils and external jackets. Coils are particularly suitable for low viscosity Hquids in combination with turbine impellers, but are unsuitable with process Hquids that foul. Jackets are more effective when using close-clearance impellers for high viscosity fluids. For jacketed vessels, wall baffles should be used with turbines if the fluid viscosity is less than 5 Pa-s (50 P). For vessels equipped with cods, wall baffles should be used if the clear space between turns is at least twice the outside diameter of the cod tubing and the fluid viscosity is less than 1 Pa-s (10... 

Total pressure will only change in a fluid if shaft work or work of extraneous forces are introduced. Therefore, total pressure would increase in the impeller of a compressor or pump it would remain constant in the difmser. Similarly, total pressure would decrease in the turbine impeller but would remain constant in the nozzles. 

Batch extraction of octanoic acid from water and corn syrup into xylene, paraffin oil, and their mixtures baffled vessel, turbine impeller. proportional to... 

The Oldshue-Rushton (Mixco) extractor is similar in construction to the RDC in the fact that it is a relativelv open design, consisting of a series of compartments separated by horizontal stator baffles. The major difference from the RDC is that the height/diameter ratio of the compartments is greater, each compartment is fitted with vertical baffles, and the mixing is accomplished by means of a turbine impeller rather than a disc. 

Close-Clearance Stirrers For some pseiidoplastic fluid systems stagnant fluid may be found next to the -essel walls in parts remote from propeller or turbine impellers. In such cases, an anchor impeller maybe used (Fig, 18-6), The fluid flow is principally circular or helical (see Fig, 18-7) in the direction of rotation of the anchor. Whether substantial axial or radial fluid motion also occurs depends on the fluid iscosity and the design of the upper blade-supporting spokes. Anchor agitators are used particularly to obtain irnpro ed heat transfer in high-consistency fluids,... 

For non-New tonian fluids, viscosity data are very important. Every impeller has an average fluid shear rate related to speed. For example, foi a flat blade turbine impeller, the average impeller zone fluid shear rate is 11 times the operating speed. The most exact method to obtain the viscosity is by using a standard mixing tank and impeller as a viscosimeter. By measuring the pow er response on a small scale mixer, the viscosity at shear rates similar to that in the full scale unit is obtained. 

Paddle A paddle is similar to a turbine impeller but typically has only two large blades and operates at lower speeds than a turbine. They are primarily used in high viscosity mixing operations. In European and Japanese literature the term "paddle" also is used to describe the flat blade and pitched blade turbines discussed above. The term "turbine" generally is reserved for disk turbines. 

Prochazka and Landau [19] developed a mixing time conelation for a single Rushton turbine impeller in a baffled tank in the standard configuration for > 10" ... 

Proportions of a stiiTcd tank relative to the diameter D liquid level = D turbine impeller diameter = D/3 impeller level above bottom = D/3 impeller blade with = D/15 four vertical baffles with width = D/10. 

Kreisel-pumpe, /. centrifugal pump rotary pump, -rad, n. turbine turbine rotor, turbine impeller, -verdichter, m. turbocompres-sor. 

Rgure 5-5S. Four-blade, vertical flat blade turbine impeller. Very versatile, one of the most used in wide application range. Courtesy of Philadelphia Gear Corp. 

Figure 5-5T. Standard six-blade vertical curved blade turbine impeller. Gives good efficiency per unit of horsepower for suspensions, mixing fibrous materials. Gives high pumping capacity. Courtesy of Philadelphia Gear Corp.

Figure 5-7 is an analysis flow chart for examining types of turbine impeller performance requirements. 

Figure 5-7. Analysis flow chart for examining types of turbine impeller applications. By permission, Gates, L. E., et a ., Chem. Eng., Dec. 8, 1975, p. 110 [26].

The turbine should be positioned to give 35% of the liquid below and 65% above the turbine. For depths exceeding these values, multiple impellers should be used. For total liquid depths less than the effective height of a turbine impeller, the turbine should be located 0.35 Z from the tank bottom, unless there is an ov erriding restraint. 

For a turbine the preferred location for w ithdrawal of mixed fluid is at the side opposite the turbine impeller. y study of the flow pattern of the system should be made to... 

A bacterial fermentation was carried out in a reactor containing broth with average density p = 1200kg/m3 and viscosity 0.02N-s/m2. The broth was agitated at 90rpm and air was introduced through the sparger at a flow rate of 0.4 vvm. The fermenter was equipped with two sets of flat blade turbine impellers and four baffles. The dimensions of vessel, impellers and baffle width were ... 

Figure 5-5S. Four-blade, vertical Figure 5-5T. Standard six-blade fiat blade turbine Impeller. Very vertical curved blade turbine versatile, one of the most used impeller. Gives good efficiency in wide application range. Cour- per unit of horsepower for sus-tesy of Philadelphia Gear Corp. pensions, mixing fibrous materials. Gives high pumping capacity. Courtesy of Philadelphia Gear Corp.

El), Oldshue (Ol), and Johnson et al. (J4)] have been concerned with the determination of the volume transfer coefficient KtAb (liter/hr), where Kx is the mass-transfer coefficient and Ab is the total gas-liquid interfacial area. The results obtained using a turbine impeller and an open pipe sparger can be correlated in terms of the nominal gas velocity wg(ft/hr) and the horsepower input to the impeller HP by an expression of the following form ... 

From their experimental work, they obtained the following values for the exponents for a turbine impeller ... 

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