Centrifugal pumps capacity-head range

Approximate Capacity-Head Ranges For Centrifugal Pumps... 

Figure 7.8. Topical capacity-head ranges of some centrifugal pumps, their 1978 costs and power requirements. Suction and discharge are in inches (Evans, 1979, Vol. 1).

Tests conducted to operate centrifugal pumps as hydrauhc turbines throughout the head-capacity-speed range show that a good centrifugal pump generally makes an efficient hydraulic turbine. From theoretical considerations it is possible to state that at the same speed... 

Power consmnption the operating point of centrifugal pump should be chosen at the highest efficiency possible. Generally, the vendors/manufacturers offer a range of models, which cover the requirements of capacity, head, etc. However, the final selection should be done while keeping in mind the most likely (normal) condition in which the pump will be ran. In case of positive displacement pumps the performance curves should be studied to select proper speed for the capacity and required head... 

The centrifugal pump is the type most widely used in the chemical industiy for transferring liquids of aU types—raw materials, materials in manufacture, and finished produc ts—as well as for general services of water supply, boiler feed, condenser circulation, condensate return, etc. These pumps are available through avast range of sizes, in capacities from 0.5 mVh to 2 X 10 mVh (2 gal/min to 10 gaJ/min), and for discharge heads (pressures) from a few meters to approximately 48 MPa (7000 Ibf/iu"). The size and type best suited to a particular apphcation can be determined only by an engineering study of the problem. 

External rotary gear pumps are particularly suitable for moderate-to-very high-kinematic viscosity liquids in the range of 100 to 500,000 centistokes for flow capacities to at least 1,500 gpm (0.252 mVs) and heads to at least 3,000 ft (914.4 m). They are moderately priced, but usually more expensive than radial centrifugal pumps. They cannot be used with liquids containing particles and do not give as smooth a flow rate as do radial centrifugal pumps. 

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