Multi-stage pumps are centrifugal pumps with multiples of impellers arranged in series. Essentially, each stage adds additional pressure to the final output without changing the flow, allowing centrifugal pumps the ability to achieve quite high heads.
They are split into two distinct groups;
Vertical Multi-stage for lower flows & small foot print area typically found boosting pressures in multi-storey buildings & light industry.
Horizontal Multi-stage for larger flows & heads found in boiler feed & underground de-watering applications
Can achieve quite high heads at low flow demands
Works well with Variable Speed Technologies
Tolerates some variations in flow demands
Vertical multi-stage pumps are inexpensive to manufacture in stamped stainless steel or composite plastics.
Horizontal multi-stage pumps use cast metals but are less expensive & quieter than positive displacement pumps with flows above 20m3/hr
Little maintenance required
Generally for use with clean, low viscosity liquids only
Develop a lot of thrust which must be balanced or stabilized
Do not tolerate ‘off curve’ operation.
Common brands serviced include;
Standart, TKL, Worthington, KSB, Caprari, Ritz, Grundfos, Lowara, Franklin, Calpeda, SPX, Goulds, Flowserve, Southern Cross, Sulzer, Kirloskar, Ebara