Boiling Fluids - Max Suction Flow Velocities

Recommended max suction flow velocity when pumping boiling fluids. Capacity problems, cavitation and higher power consumption in pumps are often the result of suction side conditions.

Pipe bore (inches)Pipe bore (mm)Max Velocity (m/s)Max Velocity (ft/s)
1250.31
2500.31
3750.31
41000.31
61500.351.1
82000.381.2
102500.451.5
123000.451.5

Key Considerations

Boiling liquids - due to cavitation - may be extremely difficult to pump. If the pressure at any point within a pump falls below the vapor pressure of the liquid being pumped, vaporization or cavitation will occur.

For example, water at 100°F (38°C) boils or vaporizes if exposed to a vacuum of 28 in Hg. The problem with cavitation increases with higher temperatures.

Related Topics

  • Condensate Pumping - the challenge with pumping condensate with high temperature and the cavitation of pump wheels
  • Steam Systems and Feeding Pumps Suction Lift - information about steam feed pumps
  • Cavitation and NPSH - an introduction to cavitation and Net Positive Suction Head NPSH