Impeller centrifugal-pump

Similar to multistage centrifugal pumps, centrifugal compressors, as shown in Figure 10-9, use a series of rotating impellers to impart velocity... 

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

The general operation of a centrifugal compressor is like a centrifugal pump, except that the fluid is compressible. Theoretically, the head developed by a centrifugal impeller or wheel is the same regardless of the characteristics of the... 

Pumps, centrifugal, Francis impeller—starting with ... 

In a vibration analysis, hydraulic instability is displayed at the vane-pass frequency of the pump s impeller. Vane-pass frequency is equal to the number of vanes in the impeller multiplied by the actual running speed of the shaft. Therefore, a narrowband window should be established to monitor the vane-pass frequency of all centrifugal pumps. 

The pressure developed by a centrifugal pump depends on the fluid density, the diameter of the pump impeller, the rotational speed of the impeller, and the volumetric flow rate through the pump (centrifugal pumps are not recommended for highly viscous fluids, so viscosity is not commonly an important variable). Furthermore, the pressure developed by the pump is commonly expressed as the pump head, which is the height of a column of the fluid in the pump that exerts the same pressure as the pump pressure. 

You must select a centrifugal pump that will develop a pressure of 40 psi when pumping a liquid with an SG of 0.88 at a rate of 300 gpm. From all the pump characteristic curves in Appendix H, select the best pump for this job. Specify pump head, impeller diameter, motor speed, efficiency, and motor horsepower. 

Rirbine Pumps The term turbine pump is applied to units with mixed-flow (part axial and part centrifugal) impellers. Such units are available in capacities from 20 mVh (100 gal/min) upward for heads up to about 30 m (100 ft) per stage. Turbine pumps are usually vertical. 

Chemicals, Chlor alkali. Paper and pulp, Fertilizers, Oil drilling and Pharmaceu ticals Chemical resistant linings for storage tanks, road and ship tankers, process vessels, pipelines, valves, pumps, filters, agitators, centrifuges, impellers, etc. Soft natural rubber or ebonite, neoprene, butyl and hypalon depending on operating temperature, and application. 

Let us assume liquid flows from an 8-in line into the suction of a centrifugal pump. The liquid enters the pump s impeller through a circular opening, called the eye of the impeller, in the center of the impeller. Let us assume that this eye has a diameter of 2 in. 

In general, a centrifugal impeller can discharge its flow in three ways by directly throwing the flow radially into the side of the chamber circumscribing it, by conveying the flow forward by proper design of the impeller, and by a mix of forward and radial throw of the flow. The pump that uses the first impeller is called a radial-flow pump, the second, as mentioned previously, is called the axial-flow pump and the third pump that uses the third type of impeller is called a mixed-flow pump. The impeller in c is used for mixed-flow pumps. 

To avoid cavitation, the pressure at the pump inlet must exceed the vapor pressure by a certain value, called the net positive suction head (NPSH). The required value of NPSH is about 2 to 3 m (5 to 10 ft) for small centrifugal pumps, but it increases with pump capacity, impeller speed, and discharge pressure, and values up to 15 m (50 ft) are recommended for very large pumps. For a pump taking suction from a reservoir, like that shown in Fig. 8.5, the available NPSH is customarily calculated as... 

Example 9.3. A typical centrifugal pump runs at 1800 rpm (mainly because of the convenient availability of 1800 rpm electric motors). If the fluid being pumped is water, what is the maximum pressure difference across the pump for impeller diameters of 1, 3, and 10 in ... 

Pump test results on a centrifugal water pump with impeller diameter of 14.62 in. (From R. L. Daugherty and J. B.j Franzini, Fluid Mechanics with Engineering Applications, 6th ed, McGraw-Hill, New York, 1965. Reproduced by permission of the publisher.)... 

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