In general, pumps can be divided into two categories:  positive displacement (PD) pumps and centrifugal pumps.  Centrifugal pumps have a rotary type of operation whereas PD pumps can be a rotary type or a reciprocating type.  Some of the advantages of positive displacement pumps vs. centrifugal pumps include the ability to produce constant flow against increasing discharge pressures, the ability of handling much higher viscosities, and operating at higher pump efficiencies in general.

The Tri-Rotor rotary piston pump is a positive displacement (PD) pump in the same family of other rotary PD pumps such as internal gear, external gear, rotary (or sliding) vane, lobe, progressing cavity, and peristaltic (or hose) pumps.  Reciprocating positive displacement pump types include the piston/plunger style and diaphragm pumps like the air-operated double-diaphragm pump.  Like other PD pumps, the rotary piston pump discharges a specific volume of fluid for each full revolution of its’ rotation.  

  Tri- Rotor Rotary Piston Internal Gear External Gear Rotary Vane Lobe Progressing Cavity Peristaltic Piston/Plunger AODD Centrifugal
Long Life A B B B B D C C C B
Efficiency A A A A A A B B D B
Viscous Fluids Handing A A A C A A B A A D
Footprint A A B A A D C A B B
Maintenance Costs A C C C C D C D A B
Shear sensitive B C C C C C C D A C
Self-priming B B B B B A B A A D
Solids Handling B D D D A D C C A D
Handling Abrasives B B D D B A C B A B
A = Excellent     B = Good     C = Fair     D = Poor
You can see more about the operating principles of the Tri-Rotor pump and how it works here.  If you have any questions about our pump, we’d love to hear from you.