-PUMPS

1                 Power for pumping liquids: HP = (gpm)(psi difference)/(1714) (fractional efficiency).

2                 Normal pump suction head (NPSH) of a pump must be in excess of a certain number, depending on the kind of pumps and the conditions, if damage is to be avoided. NPSH = (pressure at the eye of the impeller - vapor pressure)/(density). Common range is 4-20 ft.

3                 Specific speed Ns = (rpm)(gpm)o.s/(head in ft)^0.75. Pump may be damaged if certain limits of Ns are exceeded, and efficiency is best in some ranges.

4                 Centrifugal pumps: Single stage for 15-5000 gpm, 500 ft max head; multistage for 20-11,000 gpm, 5500 ft max head. Efficiency 45% at 100 gpm, 70% at 500 gpm, 80% at 10,000 gpm.

5                 Axial pumps for 20-100,000 gpm, 40 ft head, 65-85% efficiency.

6                 Rotary pumps for 1-5000 gpm, 50,000 ft head, 50-80% efficiency.

7                 Reciprocating pumps for 10-10,000 gpm, 1,000,000 ft head max.   Efficiency 70% at 10 HP, 85% at 50 HP, 90% at 500 HP.