Types of Pumps: Complete Guide to Centrifugal, Positive Displacement, and Specialty Pumps

The types of pumps commonly used in industry, water systems, and laboratory settings fall into two broad families: kinetic (centrifugal and axial) and positive displacement (reciprocating and rotary). Understanding the basic operation and typical applications of each type of pump helps match pump selection to required flow, pressure (head), fluid properties, and solids content.

Types of pumps: overview and main groups

Centrifugal pumps

Centrifugal pumps use a rotating impeller to impart kinetic energy to the fluid, converting it to pressure (head) in the volute. They are common in municipal water systems, HVAC, irrigation, and many process applications. Variants include single-stage, multistage, axial-flow, and mixed-flow designs that trade off head and flow.

Advantages: relatively simple, compact, continuous flow, and good for low-viscosity fluids. Limitations: performance drops with high viscosity, and they are sensitive to cavitation and required net positive suction head (NPSH).

Multistage, axial, and submersible centrifugal variants

Multistage pumps stack impellers to generate high head for boiler feed or reverse osmosis. Axial-flow pumps produce very high flow at low head for river pumping or flood control. Submersible centrifugal pumps operate while submerged for drainage and sewage applications.

Positive displacement pumps

Positive displacement (PD) pumps move a fixed volume of fluid per cycle, so flow is proportional to speed and largely independent of discharge pressure. PD pumps are suitable for viscous fluids, shear-sensitive materials, and precise metering. Two main categories are rotary and reciprocating.

Rotary positive displacement

Rotary PD pumps include gear, lobe, vane, and peristaltic pumps. Gear and lobe pumps handle oils and slurries; peristaltic (hose) pumps isolate fluid in a flexible tube and are used for corrosive or sterile fluids because the pump body does not contact the fluid.

Reciprocating positive displacement

Reciprocating pumps (piston or diaphragm) generate high pressures and precise delivery, often used for hydraulic systems, high-pressure cleaning, and dosing. Diaphragm pumps also provide good sealing for hazardous fluids.

Specialty pumps

Special-purpose pumps include:

• Slurry pumps designed for abrasive, solids-laden fluids.
• Metering and dosing pumps for controlled chemical addition.
• Vacuum pumps (rotary vane, rotary screw, or liquid ring) to produce negative pressure.
• Magnetic-drive pumps that eliminate shaft seals for leak-sensitive applications.

How pumps are classified and selected

Flow rate and head

Flow (volume per time) and head (pressure expressed as equivalent height of fluid) form the fundamental performance requirements. Centrifugal pumps are selected from pump curves showing flow vs head; positive displacement pumps are chosen for specific flow at given speed and pressure.

Fluid properties and solids handling

Viscosity, temperature, corrosivity, and solids concentration influence pump type. High-viscosity fluids favor positive displacement designs, while solids-laden slurries require heavy-duty centrifugal or specific slurry pumps with abrasion-resistant materials.

NPSH, cavitation, and seals

Cavitation is a risk when inlet pressure is too low; the net positive suction head available (NPSHa) must exceed the pump’s NPSH required (NPSHr). Seal design (mechanical seals, gland packing, or seal-less magnetic drives) depends on fluid hazards and permitted leakage.

Efficiency and operating considerations

Efficiency curves, part-load behavior, maintenance intervals, and costs (purchase and lifecycle) are part of selection. Industry standards and testing protocols from organizations such as ASME and the Hydraulic Institute help verify performance.

Typical applications by pump type

Centrifugal

Water supply, HVAC, large-volume transfer, irrigation, cooling towers.

Gear, lobe, and rotary

Lubricants, food processing, chemical transfer, polymer handling.

Diaphragm and peristaltic

Sludge handling, chemical dosing, medical and laboratory fluid transfer.

Reciprocating

High-pressure injection, hydraulic systems, testing rigs, and metering at high pressures.

For performance guidelines, energy-saving opportunities, and further technical resources on pumps and motors, consult the U.S. Department of Energy's pump resources (energy.gov).

Common performance terms to know

Flow rate (Q)

Volume per time, usually expressed in liters per minute (L/min), gallons per minute (gpm), or cubic meters per hour (m3/h).

Head

Pressure expressed as a column of fluid (meters or feet). Total dynamic head includes static lift and friction losses in piping.

NPSH and cavitation

NPSH available must exceed NPSH required to avoid cavitation; this is critical for centrifugal pumps operating near vapor pressure.

Viscosity and solids

Viscous fluids reduce centrifugal pump performance and may necessitate positive displacement designs; solids require larger clearances or specialized impeller/liner materials.

Maintenance and safety considerations

Routine inspection

Monitor vibration, temperature, seal leakage, and performance trends. Follow manufacturer and industry-recommended maintenance schedules and safety procedures.

Regulatory and standards references

Standards from organizations such as ASME, ISO, and the Hydraulic Institute, plus local regulations for pressure equipment and environmental controls, are commonly referenced for design and compliance.

Frequently asked questions

What are the types of pumps and how do they differ?

Types of pumps are broadly divided into kinetic (centrifugal and axial) and positive displacement (rotary and reciprocating). Kinetic pumps accelerate fluid to produce flow and are suited for low-viscosity, high-flow applications; positive displacement pumps move a fixed volume per cycle and suit viscous or metered applications.

Which pump type is best for abrasive slurry?

Slurry pumps with heavy-duty impellers and wear-resistant liners are designed for abrasive solids; positive displacement pumps are generally not suitable for high-solid slurries.

How does viscosity affect pump selection?

High-viscosity fluids reduce centrifugal pump efficiency and can require positive displacement pumps or specially designed centrifugal models rated for viscous service.

When is a submersible pump appropriate?

Submersible pumps are used when the pump must operate underwater or directly in the fluid, for dewatering, sewage, or submerged pumping where priming and inlet flooding otherwise present challenges.