Minimum Continuous Flow

There are three factors which must be looked at with respect to minimum flow. These are:

        Minimum Continuous Flow
Where Qmm   =   minimum flow rate for 15 deg. F temp rise. (GPM)
BHP   =   the power input at the minimum flow. (BHP)
2.95   =   constant, for 15 deg. F rise (HP-Lb-Min-deg. F/BTU-Gal.)
        Note: for 20 deg. F rise use 3.93 instead of 2.95.
        Note: for 10 deg. F rise use 1.96 instead of 2.95.
        Note: for 5 deg. F rise use 1.00 instead of 2.95.
Cp   =   specific heat, (BTU/lb-deg. F).
SpGr   =   Specific Gravity of the pumped fluid.


It is important to understand that a catastrophic failure of any pump can occur if the liquid within the pump casing is allowed to vaporize. To prevent flashing, a flow must be maintained through the pump which will keep the liquid below its saturation temperature.