Types of vertical turbine pump and their Working Principles

Vertical turbine pumps are widely used for municipal water supply, industrial cooling systems, irrigation, flood control, firefighting, and raw water intake from rivers, lakes, reservoirs, and the sea.

They are particularly useful when the water level changes significantly or when the pump has to draw water from a deep wet well, tank, reservoir, or underground source. The pumping element remains below the water level, while a vertical shaft and column pipe carry power downward and move the pumped liquid upward.

If you are comparing different vertical turbine pump types or trying to understand vertical turbine pump working principles, the most important things to look at are the hydraulic design, number of stages, installation arrangement, and pumped liquid.

A vertical turbine pump is a type of vertical long-shaft pump with its impeller submerged in the pumped liquid. The motor is normally installed above the mounting floor or discharge head. Power from the motor is transmitted through a vertical shaft to the impeller below the water level.

Liquid enters through the bottom of the pump, passes through the impeller and diffuser bowl, and then flows upward through the column pipe. At the top of the pump, the liquid is directed into the discharge pipeline through a discharge head or elbow.

LC vertical long-shaft pumps are available as single-stage or multistage suspended pumps and can be configured in VS1 or VS6 arrangements.

A typical vertical turbine pump includes:

• A vertical motor and motor support
• A discharge head or discharge elbow
• A head shaft, line shafts, and impeller shaft
• Shaft couplings
• Column pipes
• Line shaft bearings and bearing retainers
• Diffuser bowls
• One or more impellers
• A suction bell or inlet strainer

Because the pump is installed vertically, it requires relatively little floor space. The number of column pipes and shaft sections can also be adjusted to suit different installation depths.

The vertical turbine pump working process can be divided into five basic stages: power transmission, liquid entry, energy transfer, pressure recovery, and discharge.

1. The Motor Drives the Vertical Shaft

When the motor starts, torque is transferred through the coupling to the head shaft, line shafts, and impeller shaft. This shaft system drives the submerged impeller.

Bearings positioned along the shaft support it and limit radial movement. Correct shaft alignment and bearing lubrication are essential, especially on pumps with long setting depths.

2. The Submerged Impeller Draws In the Liquid

The impeller is installed below the minimum operating water level. Because the pumping element is already submerged, the pump normally does not require the same vacuum priming system used by a conventional surface-mounted centrifugal pump.

Liquid enters vertically through the suction bell or inlet opening. For open-tank installations, a strainer can be installed to stop larger debris from entering and damaging the impeller or diffuser passages.

3. The Impeller Adds Energy to the Liquid

As the impeller rotates, it transfers mechanical energy from the motor to the liquid. This increases the liquid velocity and pressure.

The impeller design determines how the liquid moves through the pump and whether the unit is best suited to higher head, medium head, or high-flow and low-head service.

4. The Diffuser Recovers Pressure

After leaving the impeller, the liquid enters the diffuser bowl. The diffuser guides the flow and converts part of its velocity into pressure.

In a multistage vertical turbine pump, the liquid then enters the next impeller and receives another increase in energy. Each additional stage increases the total head that the pump can produce.

5. The Column Pipe Carries the Liquid Upward

The pressurized liquid travels upward through the column pipe. It then enters the discharge head or elbow and leaves the pump through a horizontal outlet connected to the external piping system.

In simple terms, this is how a turbine pump works: the motor drives a submerged impeller through a vertical shaft, the impeller and diffuser increase the liquid pressure, and the column assembly carries the liquid to the surface.

Single-Stage Vertical Turbine Pump

A single-stage pump has one impeller and one diffuser bowl. It has fewer internal components and is normally used when the required discharge head is low or moderate.

Its main advantages include:

• A relatively simple construction
• Easier installation and maintenance
• Fewer bowl assembly components
• Good suitability for high-flow, low-to-medium-head applications

Multistage Vertical Turbine Pump

A multistage pump has two or more impellers and diffuser bowls arranged in series. The liquid gains additional energy as it passes through each stage, allowing the pump to generate a higher total head.

Multistage vertical turbine pumps are commonly used for:

• Deep-well water extraction
• Elevated tank filling
• Industrial process water
• High-pressure firefighting systems
• Long-distance water transfer
• Applications requiring higher discharge pressure

Adding stages mainly increases head rather than flow. The final number of stages should be selected according to the required duty point, pump speed, available NPSH, minimum water level, column pipe losses, and motor power.

1. Vertical Long-Shaft Centrifugal Pump

The vertical long-shaft centrifugal pump is one of the most common vertical turbine designs. Liquid enters near the center of the impeller and moves outward under centrifugal force before passing into the diffuser and column pipe.

Its main characteristics include:

• Single-stage and multistage configurations
• A wide available head range
• Adjustable shaft and column lengths
• Suitability for clean water, circulating water, cooling water, rainwater, and selected industrial liquids

Available duty points can cover flow rates from approximately 50 to 8,400 m³/h and heads from 10 to 300 m. The final model must be selected according to the required flow, total dynamic head, liquid properties, setting depth, and installation conditions.

2. Vertical Mixed-Flow Pump 

A mixed-flow pump produces both radial and axial flow. The liquid leaves the impeller at an angle rather than moving mainly outward, as in a centrifugal pump, or almost completely along the shaft, as in an axial-flow pump.

Mixed-flow pumps are often selected for:

• High-flow applications
• Low-to-medium heads
• Municipal drainage
• Agricultural irrigation
• Circulating water systems
• Flood control and water transfer

They are a practical middle option when an axial-flow pump cannot produce enough head but a centrifugal design would be unnecessarily restrictive for the required flow.

3. Vertical Axial-Flow Pump

A vertical axial-flow pump uses a propeller-type impeller. The liquid moves mainly in the direction of the pump shaft, and the rotating blades generate the axial force needed to move it through the guide vanes and discharge passage.

Axial-flow pumps are designed for very large flow rates at relatively low heads. Common applications include:

• Flood drainage
• Large irrigation systems
• Stormwater pumping
• River and lake water transfer
• Power plant circulating water
• Other high-flow, low-head pumping duties

Although a vertical axial-flow pump may also use a vertical installation and long shaft, it is not exactly the same as a conventional vertical turbine pump. For an English-language website, vertical axial flow pump and vertical turbine pump should be presented as separate product terms so that customers can identify the correct hydraulic design.

4. Submersible Axial-Flow and Tubular Pumps

A submersible axial-flow pump combines the motor and pump in one underwater unit. A submersible tubular pump is installed directly inside a pipe or flow passage so that the water moves through the complete pump assembly.

Their main advantages include:

• High flow capacity at low head
• No conventional long-shaft system
• Compact pumping station layout
• Multiple installation options
• Suitability for stormwater, flood control, irrigation, and large water-transfer projects

Depending on the site, these pumps can be installed in a vertical shaft, on a foundation, at an angle, or directly inside a pipeline.

Submersible axial-flow and tubular pumps should not normally be grouped under the standard vertical turbine pump category. They are better presented as related solutions for high-flow pumping projects.

Clean-Water Type

A standard clean-water pump is used for water or liquids with physical and chemical properties similar to water. Typical applications include municipal water supply, industrial water intake, cooling water, and agricultural irrigation.

Abrasion-Resistant Type

An abrasion-resistant pump is designed for liquids containing sediment or abrasive particles, such as river water with sand, mill scale water, ash water, or liquids that tend to crystallize.

Depending on the operating conditions, the impeller, diffuser bowls, wear rings, shaft sleeves, and other wetted parts can be manufactured from more wear-resistant materials.

Corrosion-Resistant Type

Corrosion-resistant pumps are used for seawater, acidic or alkaline liquids, and corrosive industrial wastewater.

Material selection should be based on the liquid composition, concentration, temperature, chloride content, and expected corrosion mechanism. Available materials may include stainless steel, duplex stainless steel, and other corrosion-resistant alloys.

Can-Type or Barrel-Type Pump

A can-type vertical turbine pump has an outer barrel surrounding the bowl and column assembly. This arrangement improves suction conditions and is often used for condensate, oil products, and liquids that require better cavitation performance.

It is also useful when the site does not have an open wet well and the pump must be connected to a closed piping system or pressure vessel.

Sewage-Type Vertical Turbine Pump

A sewage-type vertical long-shaft pump must be designed around solids passage, bearing protection, and wear resistance.

A shaft enclosing tube can be used to isolate the shaft and line shaft bearings from the pumped liquid. Clean external flushing water may then be supplied to the bearings to prevent wastewater and abrasive particles from entering the bearing clearances.

For sewage containing large solids or long fibers, the impeller type, passage size, inlet strainer, materials, and anti-clogging design must be checked carefully.

Impeller and Diffuser

The impeller transfers mechanical energy to the liquid. The diffuser controls the flow leaving the impeller and converts velocity into pressure.

The impeller and diffuser must be matched to the required flow, head, speed, and efficiency range. This applies to both single-stage and multistage pumps.

Vertical Shaft and Couplings

The shaft transmits power from the motor at floor level to the submerged impeller. On deeper installations, the shaft is divided into several sections connected by threaded or sleeve couplings.

This sectional construction makes the pump easier to manufacture, transport, install, and maintain.

Line Shaft Bearings

Line shaft bearings are installed at intervals along the shaft to control radial movement and keep the rotating assembly stable.

The bearing material and lubrication method depend on the pumped liquid. Clean-water pumps may use the pumped liquid for lubrication. Wastewater applications may require an enclosing tube and an external supply of clean lubricating water.

Thrust Bearing

The pump produces axial thrust during operation, and the rotating assembly also has its own weight. These loads must be carried by a thrust bearing.

The thrust bearing may be installed in the motor support, or the pump may use a vertical motor with an integrated thrust bearing.

Shaft Seal and Sleeves

The shaft seal at the top of the pump may use packing or another sealing arrangement selected for the project.

Replaceable sleeves are commonly fitted at sealing and bearing positions. These sleeves protect the main shaft from wear and are less expensive to replace than the shaft itself.

Before selecting a vertical turbine pump, confirm the following operating conditions.

1. Required Flow and Head

Total dynamic head must include the static lift, pipe friction, fitting losses, valve losses, and required pressure at the discharge point. Selecting a pump only from the difference in water level can lead to an incorrect duty point.

2. Minimum and Maximum Water Levels

The minimum operating level determines the required impeller submergence and affects cavitation performance, vortex formation, and stable operation.

Maximum water level is also important for checking the discharge head, foundation, shaft length, and maintenance arrangement.

3. Pump Setting Depth

The setting depth determines the number of shaft sections, column pipes, and line shaft bearings. A deeper setting also places greater demands on shaft alignment, vibration control, and installation accuracy.

4. Liquid Properties

The pump supplier should know the temperature, density, corrosiveness, solids concentration, particle size, and whether the liquid contains fibers or crystallizing materials.

5. Installation Arrangement

The installation may use an open wet well, a concrete shaft, a steel can, a pressure barrel, or another arrangement. Foundation elevation, intake geometry, access space, and lifting conditions should be confirmed before the pump is selected.

6. Hydraulic Pump Type

For higher-head service, a multistage vertical turbine pump is often the most practical option. For high-flow and low-head service, an axial-flow, mixed-flow, or submersible tubular pump may be a better fit.

7. Materials and Bearing Lubrication

Clean water, seawater, industrial wastewater, and liquids containing abrasive solids require different wetted-part materials, bearing materials, shaft protection, and lubrication systems.

8. Motor and Control System

The motor and controller should match the available power supply, starting method, required speed control, and operating frequency. A variable-frequency drive may be useful when system demand changes significantly.

Vertical turbine pumps offer several practical advantages:

• The submerged impeller normally eliminates the need for vacuum priming
• The pump can handle changing water levels
• Vertical installation saves floor space
• Additional stages can be used to produce higher head
• Shaft and column lengths can be adjusted for different setting depths
• A wide range of hydraulic designs and materials is available
• The pump can be configured for water supply, drainage, irrigation, firefighting, cooling water, and industrial intake duties

Are a Vertical Turbine Pump and a Deep Well Pump the Same?

Their applications overlap, but they are not always the same type of pump.

A deep well pump is usually compact and has a relatively small outside diameter. Its available flow, head, and motor power ranges are generally lower. These pumps are commonly used for agricultural irrigation, household water supply, livestock watering, and small groundwater extraction systems.

Some economical deep well pumps use engineering-plastic impellers to reduce weight and manufacturing cost. Their purchase price is therefore often lower. Depending on the available power supply, users can choose a standard electric version or a solar-powered pumping package.

A vertical turbine pump is generally intended for more demanding municipal and industrial duties. It is commonly used for large water-supply systems, industrial circulating water, cooling water, firefighting, mine drainage, seawater intake, and large irrigation projects.

Vertical turbine pumps are available in a much wider range of sizes, flow rates, heads, and motor powers. They can be built as single-stage or multistage units, and the shaft and column length can be adjusted to match the required setting depth.

For clean water, sewage, seawater, corrosive liquids, or abrasive service, wetted parts can be supplied in cast iron, carbon steel, stainless steel, duplex stainless steel, and other wear-resistant or corrosion-resistant materials.

Because a vertical turbine pump is usually larger, more complex, and more configurable, its purchase, installation, and maintenance costs are normally higher than those of a standard deep well pump.

As a practical rule, a deep well pump is often the more economical choice for small groundwater and agricultural irrigation projects. A vertical turbine pump is usually the better choice when the project requires higher capacity, a wider head range, special materials, greater operating reliability, or a custom-engineered configuration.

Does Adding More Impeller Stages Increase the Flow?

Not necessarily. Adding impeller stages in series mainly increases the pump head. It does not increase the flow by the same proportion.

The actual flow is determined by the hydraulic design of each stage, pump speed, impeller diameter, and resistance of the piping system.

Can a Vertical Turbine Pump Handle Sewage?

Yes, provided that the pump is designed for the actual sewage conditions.

The impeller, passage size, wetted materials, shaft protection, and bearing lubrication system must be selected according to the amount and size of solids, the presence of fibers, and the abrasiveness or corrosiveness of the liquid.

A standard clean-water configuration should not be used for sewage containing high solids or materials that can wrap around the impeller.

Is a Vertical Axial-Flow Pump a Type of Vertical Turbine Pump?

The two pump types are often used in similar projects, but they should normally be treated as separate product categories.

A conventional vertical turbine pump generally uses a centrifugal or mixed-flow impeller. A vertical axial-flow pump uses a propeller-type impeller to generate axial thrust and is designed mainly for very large flow rates at low heads.

Using the correct English product name helps buyers compare the right performance range and prevents confusion during pump selection.

Understanding turbine pump working principles starts with the relationship between the submerged impeller, vertical shaft, diffuser, and column pipe.

The motor transfers power through the shaft to the impeller. The impeller adds energy to the liquid, the diffuser converts part of the flow velocity into pressure, and the column pipe carries the liquid to the discharge system.

Each pump type has a different operating strength. A single-stage pump offers a simpler construction, while a multistage vertical turbine pump can produce much higher head. Vertical long-shaft centrifugal pumps cover a wide range of industrial duties, while mixed-flow, axial-flow, and submersible tubular pumps are often better suited to high-flow and low-head applications.

A good pump selection should never be based on the product name alone. Flow, total dynamic head, water-level variation, setting depth, liquid properties, cavitation conditions, materials, intake design, and installation arrangement all affect performance.

When these factors are checked properly, a vertical turbine pump can provide stable, efficient, and reliable operation over a long service life.