Turbine pump

American Waterworks Association (AWWA) EIOI, Deep Well Vertical Turbine Pumps... 

Turbine Pumps The term Turbine pump is applied to units with mixed-flow (part axial and part centrihigal) 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. 

A common form of turbine pump is the vertical pump, which has the pump element mounted at the bottom of a column that serves as the discharge pipe (see Fig. 10-46). Such units are immersed in the liquid to be pumped and are commonly used for wells, condenser circulating water, large-volume drainage, etc. Another form of the pump has a shell surrounding the pumping element which is connected to the intake pipe. In this form, the pump is used on condensate service in power plants and for process work in oil refineries. 

Change process to adjust specific gravity to design value, or throttle pump to reduce horsepower requirements. This will not correct problem with some vertical turbine pumps that have a flat horsepower-required curve. 

Although power-transmission equipment is generally simpler than the machines it connects, it nevertheless fails in seivdce as often as—if not more often than—motors, turbines, pumps, and the like. Care must be given to the proper selection and maintenance of power-transmission equipment otherwise, the best process machines cannot perform as expected. 

Deepwell turbine pump fitted with a hollow shaft motor Figure 7.3(a)... 

These motors have a lower efficiency as a result of running in liquid, causing more liquid drag and also axial thrust bearing loss, which is also a part of the motor. However, this lower efficiency of the motor is compensated by fewer mechanical and hydraulic losses in a submersible motor-pump installation, compared to a vertical turbine pump installation. 

You can only raise a column of cold water in a pipe a maximum of. S.S.9 ft with a pump in suction lift. Beyond 34 ft, the water will boil or vaporize. This is the reason why submersible pumps and vertical turbine pumps exist. I here is no limit to the distanee you can push a liquid from below, but you can only a.spirate a liquid a maximum of 34 ft from below the pump. 

Barrel or canned vertical turbine pumps can be used in-line (Piping, auxiliary booster, and low NPSH applications). 

Milk-of-lime transfer pumps should be of the open impeller centrifugal type. Pumps having an iron body and impeller with bronze trim are suitable for this purpose. Rubber-lined pumps with rubber-covered impellers are also frequently used. Makeup tanks are usually provided ahead of centrifugal pumps to ensure a flooded suction at all times. Plating out of lime is minimized by the use of soft water in the makeup tank and slurry recirculation. Turbine pumps and eductors should be avoided in transferring milk of lime because of scaling problems. 

Equipment typically consists of concentric circular compartments for mixing, flocculation and settling. Velocity gradients in the mixing and flocculation compartments are developed by turbine pumping within the unit and by velocity dissipation at baffles. For ideal flexibihty it is desirable to independently control the intensity of mixing and sludge scraper drive speed in the different compartments. 

Figure 3-14. Turbine pump. (Courtesy Roth Pump Co.)...

Centrifugal pumps with diffusion vanes are called diffusion pumps or, more recently, vertical turbine pumps. Those pumps with volute casings are called volute pumps. 

The most familiar examples of one-way clutches are the bicycle freewheel, which enables the cyclist to stop pedaling without stopping the bicycle, and the non-reversing ratchet used on vertical turbine pumps. 

No matter the duty (utilities excepted), most boiler plant systems employ electric motor-driven, single-stage or multistage centrifugal pumps to supply FW. These may be of conventional design or derivations such as a turbine pump. However, steam-driven reciprocating FW pumps (steam pumps) are still employed in some countries and for certain smaller applications. 

Turbine pumps are positive-displacement pumps They cannot be started with a closed discharge valve and require the fitting of a pressure relief valve to provide overpressure protection. 

It operates at a high efficiency over only a limited range of conditions this applies especially to turbine pumps. 

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