Types of Pumps: Classification of All Types and Subtypes

There are two main types of pumps: dynamic (rotodynamic) pumps, which add velocity to the liquid with a spinning impeller and turn it into pressure, and positive displacement pumps, which trap a fixed volume of liquid and push it out on every stroke or turn. Centrifugal pumps are the most common dynamic type; piston, diaphragm, gear, screw and vane pumps are the common positive displacement types. Every other pump name you meet, from a borewell submersible to a peristaltic dosing pump, sits under one of these two families.

Classification of pumps: the full tree

Dynamic pump types

A dynamic pump speeds the liquid up with a rotating impeller, then slows it down in a volute or diffuser so the velocity becomes pressure. The flow it delivers depends on the pressure it works against: close the discharge valve and flow drops to zero while pressure rises only to a limited “shut-off” value.

Centrifugal pumps by flow direction

• Radial flow: liquid enters at the eye of the impeller and leaves at right angles, outward. Gives high head at modest flow. Most water supply, building and process pumps are radial.
• Mixed flow: liquid leaves at an angle between radial and axial. Medium head, large flow. Used for irrigation lift schemes, cooling water and storm water.
• Axial flow (propeller): liquid moves parallel to the shaft, pushed by a propeller. Very large flow at low head, a few metres. Used for flood control, canal lifting and condenser circulating water in power plants.

Centrifugal pumps by construction

• Single-stage vs multistage: one impeller, or several in series on one shaft. Each stage adds head, so multistage pumps serve high-rise building boosters and boiler feed.
• End-suction: inlet on the shaft axis, outlet at the top. The standard, low-cost general-purpose pump, often as a monoblock (motor and pump on one shaft), the familiar domestic and farm “monoset”.
• Split-case: the casing splits horizontally so the rotor can be lifted out without disturbing the pipes. Double-suction impeller, large flows; used for municipal water mains, fire mains and chilled-water plants in HVAC systems.
• Vertical turbine: a column of stacked bowls hangs into a sump or well, with the motor on top. Used for river intakes, cooling towers and deep sumps.
• Submersible: a sealed motor and multistage pump run underwater together. The standard borewell pump in India; also used for sewage and dewatering.
• Magnetic drive: the motor turns the impeller through a magnetic coupling across a sealed shell, so there is no shaft seal to leak. Used for acids, solvents and toxic chemicals.

Special dynamic pumps

• Jet pump (ejector): a high-speed jet of water through a nozzle creates suction and drags more water with it. Paired with a centrifugal pump for shallow and medium wells; no moving parts down the well, but low efficiency.
• Regenerative (peripheral) pump: a flat impeller with many small vanes on its rim recirculates the liquid repeatedly as it travels round the casing. High head at small flow from a compact pump; used for domestic pressure boosting and boiler feed in small plants.

Positive displacement pump types

A positive displacement (PD) pump delivers almost the same volume per revolution or stroke whatever the pressure. If the outlet is blocked, pressure keeps rising until something bursts or the motor stalls, so every PD pump needs a pressure relief valve.

Reciprocating pumps

• Piston pump: a piston moves in a cylinder with suction and delivery valves. High pressure, pulsating flow. Used for hydraulic test rigs and older hand pumps.
• Plunger pump: a solid plunger slides through a stationary packing, so it handles higher pressures than a piston pump. Used for high-pressure washers, hydro-testing and oil-well injection.
• Diaphragm pump: a flexible diaphragm moves back and forth, so the liquid never touches a sliding seal. Used for chemical dosing (chlorine, acids), slurries and air-operated double-diaphragm (AODD) pumps on construction sites.

Rotary pumps

• Gear pump: two meshing gears carry liquid round the casing in the spaces between teeth. External and internal gear types. Used for lubricating oil, fuel oil and hydraulic power packs.
• Lobe pump: like a gear pump but with two or three rounded lobes that do not touch. Gentle on the product; used in dairies and food plants.
• Screw pump: two or three meshing screws move liquid along their length with smooth, non-pulsing flow. Used for fuel oil in ships and power stations and for viscous liquids.
• Vane pump: sliding vanes in an off-centre rotor sweep liquid from inlet to outlet. Used in vehicle power steering, hydraulics and LPG transfer.
• Peristaltic (hose) pump: rollers squeeze a flexible tube; the liquid touches only the tube. Used for medical, laboratory and accurate chemical dosing.
• Progressive cavity pump: a single helical rotor turns inside a double-helix rubber stator, forming cavities that move steadily forward. Handles sludge, slurries, paste and crude oil.

Centrifugal vs positive displacement pumps

Worked example: pump power

A centrifugal pump lifts 20 L/s of water through a total head of 30 m. Pump efficiency is 70 percent. Find the hydraulic power, shaft power and motor size.

• Q = 20 L/s = 0.02 m³/s, H = 30 m, ρ = 1,000 kg/m³, g = 9.81 m/s²
• Hydraulic power P_h = ρ g Q H = 1,000 x 9.81 x 0.02 x 30 = 5,886 W = 5.89 kW
• Shaft power P_s = P_h / η = 5.886 / 0.70 = 8.41 kW (about 11.3 HP)
• With a 90 percent efficient motor, electrical input = 8.41 / 0.90 = 9.34 kW

A 7.5 kW motor would be overloaded, so the next standard size, 11 kW, is chosen. Total head H must include static lift plus pipe friction and fitting losses, not just the height difference.

Specific speed: choosing radial, mixed or axial

Specific speed tells you which impeller shape suits a given duty:

N_s = N √Q / H^3/4, with N in rpm, Q in m³/s and H in metres, taken at the best efficiency point and per stage.

For the example duty (Q = 0.02 m³/s, H = 30 m) at 1,450 rpm: √0.02 = 0.1414 and 30^0.75 = 12.82, so N_s = 1,450 x 0.1414 / 12.82 = 16.0. At 2,900 rpm it doubles to 32.0. Both are low values, pointing to a radial-flow centrifugal pump.

In these metric units, rough bands are: radial about 10 to 80, mixed flow about 80 to 160, and axial above about 160. Textbooks draw the boundaries slightly differently, and in US units (rpm, US gpm, feet) the same bands are roughly 500 to 4,000, 4,000 to 9,000 and above 9,000. Always check which units a chart uses before comparing numbers.

NPSH and cavitation

If the pressure at the impeller eye falls below the liquid’s vapour pressure, bubbles form and then collapse violently on the vanes. This is cavitation: it causes noise, loss of head and pitted impellers. To avoid it, the net positive suction head available (NPSHa) from the system must exceed the NPSH required (NPSHr) from the maker’s curve, with a margin.

Example: water at 30 C (vapour pressure 4.25 kPa) drawn from an open sump at sea level (101.3 kPa), with 4 m suction lift and 1 m suction-pipe loss. NPSHa = (101.325 – 4.25) x 1,000 / (1,000 x 9.81) – 4 – 1 = 9.90 – 5 = 4.9 m. A pump needing more than about 4 m NPSHr here would be at risk. Lowering the pump or shortening the suction pipe helps.

How to choose a pump: selection by duty

For how these pumps are used across industries such as oil and gas, water treatment and chemicals, see our article on industrial pumps in modern applications.

Pumps in India: star labels and solar pumps

The Bureau of Energy Efficiency (BEE) runs a star labelling programme for agricultural pumpsets, including submersible and monoset pumps. It is voluntary, but star-rated sets are often required in state and utility tenders. Separately, monoset pumps come under BIS standard IS 9079 for the ISI mark.

Under PM-KUSUM, run by the Ministry of New and Renewable Energy, Component B funds standalone solar pumps of up to 7.5 HP for farmers, with the central government paying 30 percent and the state another 30 percent. The first phase was due to end in March 2026 with a second phase planned, so check the MNRE site for the current terms. Most of these are submersible or surface centrifugal pumps driven by a solar controller.

Pumps and turbines are covered in the fluid machinery course of the AICTE model curriculum for B.Tech mechanical and civil engineering.

FAQs

What are the two main types of pumps?

Dynamic (rotodynamic) pumps, such as centrifugal and axial pumps, and positive displacement pumps, such as piston, diaphragm, gear and screw pumps. Dynamic pumps add velocity; positive displacement pumps move a fixed volume per cycle.

What are the types of dynamic pumps?

Centrifugal pumps (radial, mixed and axial flow, in single-stage, multistage, end-suction, split-case, vertical turbine, submersible and magnetic drive forms) and special types such as regenerative and jet pumps.

Which type of pump is most commonly used?

The centrifugal pump. It is simple, cheap, smooth-running and handles large flows of thin liquids like water, which covers most domestic, building, agricultural and industrial duties.

Why do positive displacement pumps need a relief valve?

Because they keep pushing the same volume whatever the pressure. If the outlet is closed, pressure rises until a pipe, seal or motor fails, so a relief valve returns the flow to the suction side above a set pressure.

How do you calculate pump power?

Hydraulic power P = ρ g Q H. For 0.02 m³/s of water against 30 m head, P = 1,000 x 9.81 x 0.02 x 30 = 5.89 kW. Divide by pump efficiency (0.70) for shaft power: 8.41 kW.

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