Relations Between Head, Horsepower, Capacity. Speed

Relations Between Head, Horsepower, Capacity, Speed 

The difference between the brake horsepower and the water or liquid horsepower is the pump efficiency. The requirement in either case is the horsepower input to the shaft of the pump. For that reason, the brake horsepower represents the power required by the pump, which must be transmitted from the driver through the drive shaft through any coupling, gear-box, and/or belt drive mechanism to ultimately reach the driven shaft of the pump. Therefore, the losses in transmission from the driver to the pump itself must be added to the input requirement of the driven pump and are not included in the pump s brake horsepower requirement. 

WHP (energy delivered by pump to fluid) eHP (energy supplied to input side of pump s driver) 

For the rising type characteristic curve, the maximum brake horsepower required to drive the pump over the entire pumping range is expressed as a function of the 

Unless specifically identified otherwise, the BHP values read from a manufacturers performance curve represent the power only for handling a fluid of viscosity about the same as water and a specific gravity the same as water, i.e., SpGr = LG. To obtain actual horsepower for liquids of specific gravity other than 1.0, the curve values must be multiplied by the gravity referenced to water. Viscosity corrections are discussed in another section. Good design must allow for variations in these physical properties. 

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Effects of performance changes, 201-203 Head curve for single pump, 198 Relations between head, horsepower, capacity and speed, 200 Temperature rise 207-209 Viscosity corrections, 203-207 Purging, flare stack systems, 535 Reciprocating pumps, 215—219 Flow patterns, 219 Specification form, 219 Relief areas, 437 External fires, 451, 453 Sizing, 434, 436... 

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