Four Types of Centrifugal Pumps Explained: Radial, Axial, Mixed & More

What Are the Four Types of Centrifugal Pumps? Start with the Duty Point

An engineer selecting a pump for a high-rise booster system starts from a different duty point than a contractor managing stormwater overflow. The first may need 60 m³/h at 180 m head; the second may need 4,000 m³/h at only 4 m. Both jobs can be done with centrifugal pumps, but the impeller design that suits one will not suit the other. This is why the question “what are the four types of centrifugal pumps?” matters in practice: the answer defines the hydraulic limits of the pump before you look at motor power, materials, or vendor specifications.

The four types of centrifugal pumps, classified by impeller flow path, are radial flow pumps, axial flow pumps, mixed flow pumps, and special-purpose/configurational designs. Construction features such as single-stage versus multi-stage, self-priming versus non-self-priming, double suction, and vertical or horizontal layouts are practical variants that support specific duties, but the first decision is usually the impeller family.

The Working Principle Behind Every Centrifugal Pump

Every centrifugal pump uses the same basic physics. A rotating impeller with curved vanes receives liquid at the suction eye and throws it outward. The liquid gains kinetic energy in the impeller, and a volute or diffuser slows it down, converting that kinetic energy into pressure. The shape and angle of the impeller vanes determine the direction in which the liquid leaves the impeller: perpendicular to the shaft for radial flow, along the shaft for axial flow, or at an angle in between for mixed flow. This flow direction is the single most important factor that separates pump types. For a quick refresher on the mechanical process, see how a centrifugal pump impeller works in an industrial setting.

Because impeller geometry also sets the shape of the flow-head (Q-H) curve, the four impeller families naturally divide into different application ranges.

The Four Types of Centrifugal Pumps: Impeller Family Definitions

The standard answer to what are the four types of centrifugal pumps is based on impeller flow direction. The four groups are radial flow, axial flow, mixed flow, and special-purpose/configurational designs. The following sections explain how each type behaves, when to use it, and where common industrial product variations fit.

Type 1: Radial Flow Centrifugal Pumps

Radial flow pumps, sometimes called centrifugal force pumps, are the most common type in industrial service. Liquid enters the impeller at the eye and exits at roughly 90 degrees to the pump shaft. In a radial flow pump, most of the pressure increase comes from centrifugal force, which makes this family well suited to moderate flow with a relatively high head. Impeller designs include closed, semi-open, and open versions; closed impellers are preferred for clean liquids, while open or semi-open designs handle fluids with some solids.

A single-stage radial flow centrifugal pump is the workhorse for water supply, cooling water circulation, boiler feed, chemical transfer, HVAC systems, and general plant services. For clean-water service, a SLW series horizontal centrifugal pump represents a typical single-stage radial flow configuration. When chemical compatibility dominates, an IH series chemical centrifugal pump is a common radial-flow option. In tight piping spaces, a vertical pipeline centrifugal pump delivers the same hydraulic principle in a more compact envelope.

Wholesale SLW Series Horizontal Centrifugal Pump Manufacturers, OEM/ODM Factory Jiangsu Double Wheel Pump Machinery Manufacturing Co., Ltd. is China SLW Series Horizontal Centrifugal Pump Manufacturers and OEM Factory...View Product →

Type 2: Axial Flow Centrifugal Pumps

In contrast, axial flow pumps are propeller-like. Liquid enters and leaves along the axis of the pump shaft. Instead of relying mainly on centrifugal force, axial flow pumps generate pressure through the lifting action of the propeller blades. The result is a pump that handles very large flow rates with a low head. Axial flow pumps are often specified for flood control, stormwater pumping, irrigation canals, and condenser cooling water where the fluid is moved horizontally over short elevation changes. At these low-head, high-flow conditions, an axial flow pump can operate far more efficiently than a radial flow pump.

Type 3: Mixed Flow Centrifugal Pumps

Mixed flow pumps combine the characteristics of radial and axial flow designs. Liquid leaves the impeller at a diagonal angle, somewhere between perpendicular and parallel to the shaft. The impeller uses both centrifugal force and axial lift. A mixed flow pump delivers more flow than a radial flow pump but with a higher head than an axial flow pump, making it a good fit for medium-flow, medium-head duties. Municipal water supply, drainage stations, agricultural irrigation, and coastal stormwater systems commonly use mixed flow pumps when neither radial nor axial pumps match the system curve efficiently.

Type 4: Special-Purpose and Configurational Centrifugal Pumps

The fourth group is not a single impeller shape. It includes pumps with special impeller designs, such as vortex impellers for solids handling, and pumps built into configurations that solve a specific hydraulic problem. This is where many industrial selection decisions actually happen.

Vortex impellers are recessed in the pump casing. Solids and stringy material pass through the open volute rather than through the impeller vanes, which reduces clogging risk in sewage and wastewater duty. On the construction side, four configuration variants deserve special attention:

• Single-stage versus multi-stage: A multi-stage pump puts two or more impellers in series on one shaft. Each impeller adds pressure, so a multi-stage pump can achieve very high heads from a relatively compact casing. For boiler feed, high-rise supply, reverse osmosis, and other high-pressure duties, a SLGD series vertical multistage centrifugal pumpWholesale SLGD Series Vertical Multistage Centrifugal Pump Manufacturers, OEM/ODJiangsu Double Wheel Pump Machinery Manufacturing Co., Ltd. is China SLGD Series Vertical Multistage Centrifugal Pump Manufacturers and O...View Product → is a practical example of this approach.
• Self-priming versus non-self-priming: A self-priming centrifugal pump can evacuate air from the suction line without external priming on each start. This matters when the pump sits above the liquid level. A WFB sealfree self-priming pumpWholesale WFB Seal-Free Self-Priming Pump Manufacturers, OEM/ODM Factory - JiangJiangsu Double Wheel Pump Machinery Manufacturing Co., Ltd. is China WFB Seal-Free Self-Priming Pump Manufacturers and OEM Factory, detai...View Product → is a sealless, self-priming configuration often used where leakage and maintenance access are concerns.
• Double suction: A double suction pump admits liquid to both sides of the impeller. This balances axial thrust and lets the pump move a larger flow with less vibration than a single suction impeller of similar size. For high-flow, moderate-head services such as large water transfer, a horizontal split-case double suction centrifugal pump is a common design.
• Vertical versus horizontal: A vertical centrifugal pump saves floor space and suits deep pits, wells, and condenser bays. A vertical long shaft pump can reach submerged suction levels in a sump while keeping the motor accessible on top. For a more detailed comparison of the two installation styles, see the practical differences between horizontal and vertical centrifugal pumps.

Four Types of Centrifugal Pumps at a Glance

Before moving to the selection process, compare the four groups by hydraulic profile and typical service:

• Radial flow: moderate flow, high head; water supply, cooling, boiler feed, chemical process.
• Axial flow: high flow, low head; flood control, stormwater, irrigation, condenser circulation.
• Mixed flow: medium-high flow, medium head; municipal water, drainage, coastal pumping.
• Special-purpose/configurational: head and flow depend on design; solids handling, high-head multistage, self-priming, double suction, or vertical installation.

The boundaries are not absolute, but the hydraulic profile always comes first. If the process needs 80 m head and 60 m³/h, a radial flow pump is the natural starting point. If the process needs 4,000 m³/h at 4 m head, an axial flow pump is nearly always the right choice.

How to Select the Right Type for Your Application

Use the following order of decisions:

1. Define the duty point. Flow and head are non-negotiable. Plot them on a pump characteristic curve and identify which impeller family can operate near its best efficiency point.
2. Check the fluid. Clean water, viscous liquids, corrosive chemicals, abrasive slurries, and fibrous wastewater behave differently. An open impeller, vortex impeller, or special alloy may be necessary before the basic pump type is fixed.
3. Examine suction conditions. Determine available net positive suction head (NPSH) and decide whether the pump will need a flooded suction or a self-priming configuration. Low suction pressure increases cavitation risk and often points toward a double suction pump or an impeller with better suction-specific speed.
4. Choose installation and drive arrangement. Floor space, pit depth, and motor location decide between horizontal and vertical construction. For deep pits, a vertical long shaft pump keeps the motor accessible; for pipework galleries, horizontal pumps are easier to service.
5. Compare total operating efficiency. Energy cost over a pump’s life usually exceeds the purchase price. A nominally cheaper pump running outside its best efficiency range can burn more power in the first year.

For demanding media and environments, review the available guidance on choosing industrial centrifugal pumps for harsh conditions before you finalize the specification.

Common Mistakes to Avoid When Choosing a Centrifugal Pump

Making a good selection also means avoiding common errors that lead to field failures:

• Focusing only on flow. A pump sized for flow but not head will run far to the right of its curve, overload the motor, or cavitate.
• Ignoring liquid properties. Viscosity reduces pump performance; solids require larger passages, an open impeller, or a vortex impeller.
• Underestimating suction lift. Without enough NPSH, a centrifugal pump loses pressure and erodes the impeller. If the liquid source is below the pump, a self-priming centrifugal pump may be the practical answer.
• Choosing a vertical pump solely to save floor space. Vertical shaft pumps can be harder to maintain if the wet end is deep in a pit. Match the construction to the access plan.
• Selecting by catalogue alone. Impeller family, speed, wear ring clearance, and seal environment all need to be checked against the actual duty.

Conclusion: Build Your Selection on a Clear Understanding of Pump Types

The four types of centrifugal pumps are radial flow, axial flow, mixed flow, and special-purpose/configurational designs. They differ in how the impeller directs the liquid, and that difference governs the flow and head the pump can deliver. Single-stage and multi-stage versions, self-priming and non-self-priming layouts, double suction impellers, and vertical or horizontal mounting all refine the choice, but the impeller family is your first decision.

When you are considering a new or replacement pump, start with the duty point: flow, head, fluid characteristics, suction conditions, and installation constraints. That process will naturally lead you to one of the four types. Once the type is clear, compare actual product designs within that family to confirm efficiency, material compatibility, and maintainability. A clear understanding of these four centrifugal pump categories will save you time and prevent the most common selection mistakes.