PUMP 101

With the right information, our sales representatives can quote a pump to more precisely fit your needs.

Just let us know the following, and we'll suggest the best pump model for you:

Fluid name, concentration, specific gravity, viscosity, solids data, temperature, flammability
Total dynamic head (TDH) and flow required
NPSHa (Net Positive Suction Head available)
Description of application
Customer experience with suitable materials of construction

Please hover over the tiles below for a brief Pump 101 tutorial and the factors that influence pump selection.

Fluid Name & Concentration

Specific Gravity

Specific Gravity is the weight of a given liquid compared to the weight of the equivalent volume of water.
By definition, water has a specific gravity of 1.0, but many chemicals have specific gravities greater than 1.0.
Many solvents and petroleum distillates have a specific gravity less than 1.0.

Viscosity

Flammable Fluids

Extreme care must be taken when applying a pump for flammable fluids
Use only pumps with stainless steel construction, DB Series with PVDF construction or UC Series
Use only explosion proof motors
Use with bronze bump ring centrifugal pump option where available
Make sure all components are grounded & bonded

Flow

Flow rate is the volume of liquid that needs to be pumped
It can be expressed as GPM (gallons per minute) or metric units like m3/hr (cubic meters per hour) or lpm (liters per minute)
Flow rate is required to calculate friction loss in the users piping system

Head

Suction Head

Suction head exists when the liquid supply to the pump is ABOVE the pump
Equal to the static height in feet or meters that the liquid supply level is above the pump centerline less suction line losses
Commonly referred to as a “flooded suction” application

Suction Lift

Suction lift exists when the liquid supply to the pump is BELOW the pump.
Equal to the static height in feet or meters that the liquid supply is below the pump centerline less suction line losses
Generally, this type of application requires a self-priming pump like our SP Series

Discharge Head

System Head

System curve is a plot of the head required to make liquid flow through piping system
A centrifugal pump always operates at intersection of head-capacity curve and system curve
System curve consists of: Static head Pressure head Friction loss in pipe & fitting

Net Positive Suction Head (NPSH)

Net Positive Suction Head (NPSH) is the suction head required by the pump and provided by the piping system to avoid cavitation
Called ‘net’ because the vapor pressure is always subtracted out, therefore it is over and above or ‘net of’ the vapor pressure
Called ‘positive’ because the units are always in absolute pressure terms – either feet-absolute or meters-absolute

Cavitation

Caused when the NPSHa is lower than the NPSHr required by the pump
Cavitation bubbles are formed in the low pressure region and rapidly collapse when entering higher pressure regions in the pump, causing erosion damage
More likely with hot fluids, fluids with high vapor pressures, suction sources that are under reduced pressure (vacuum) or larger impellers operating near full flow

Temperature

Altitude

Atmosphere