Rules of Thumb
  1. Power for pumping liquids:
    Power, hp = (gpm)(psi difference) / (1,714)(fractional efficiency)
  2. If pump damage is to be avoided, normal pump suction head (NPSH) must be in excess of a certain number, depending on the kind of pump and conditions, as given by the supplier.
    NPSH = (pressure at the eye of the impeller - vapor pressure) / (density)
    The common range is 4-20 ft.
  3. Centrifugal pumps: Use single stage for 15-5,000 gpm, 500 ft maximum head; multistage for 20-11,000 gpm, 5,500 ft maximum head. Efficiency is 45% at 100 gpm, 70% at 500 gpm, 80% at 10,000 gpm.
  4. Axial pumps are for 20-100,000 gpm, 40 ft head, 65-85% efficiency.

H I N T S  A N D  R U L E S
Drying and Solids Conveyors for Particular Solids Cooling Towers Compressors and Vacuum Pumps Crushing and Grinding
Extraction, Liquid-Liquid Crystallatisation from Solution Filtration Heat Exchangers Mixing and Agitation
Particle Size Enlargement Piping Pumps Reactors Refrigeration
Piping Size Seperation of Particles Utilities, Common Specifications Vessels (Storage Tanks) Reactors
C O N T A C T   G L Y D E