What Is a Split Case Pump?

Split case pumps—also called double-suction split case pumps—are one of the most important pump types used in municipal water supply, industrial systems, HVAC cooling water, fire systems, and irrigation projects.

Their signature feature is the “split casing” design that makes them extremely stable, durable, and easy to maintain.

In this article, we explain what a split case pump is, how it works, and where it is used.

What Is a Split Case Pump? (Definition)

A split case pump is a type of centrifugal pump where the pump casing is split horizontally into two halves (upper half & lower half).

This allows easy access to:

  • impeller

  • shaft

  • bearings

  • wear rings

without removing the pipework.

Most split case pumps are also double-suction pumps, meaning water enters the impeller from both sides, creating perfect hydraulic balance.

✔ “Horizontal Split Case” = casing split horizontally

✔ “Double-Suction” = water enters from both sides of the impeller

因此：
Split case pump = efficient, stable, easy to maintain double-suction centrifugal pump.

How Does a Split Case Pump Work?

Split case pumps operate based on the double-suction impeller principle:

1. Water enters both sides of the impeller

This reduces axial thrust and stabilizes flow.

2. The impeller rotates

Centrifugal force pushes liquid outward.

3. The volute converts velocity into pressure

Flow exits through the discharge nozzle.

4. The casing can be opened horizontally

Maintenance is extremely easy, especially compared to closed volute pumps.

Why Double-Suction Design Matters

The double-suction impeller creates hydraulic balance, resulting in:

  • Lower axial load

  • Longer bearing life

  • Less vibration

  • Higher efficiency

  • Higher flow capability

This is why split case pumps are widely used in large-flow applications.

Advantages of Split Case Pumps

Split case pumps are known for their durability and performance:

✔ High Efficiency

Double suction design reduces losses; ideal for large-scale water transfer.

✔ Very Stable Operation

Low vibration, suitable for continuous 24/7 operation.

✔ Easy Maintenance

Casing splits horizontally → no need to disconnect pipelines.

✔ Long Service Life

Balanced hydraulics protect bearings and shaft.

✔ Handles Large Flow Rates

Commonly used for flows from hundreds to thousands of m³/h.

✔ Reliable for Critical Systems

Municipal and industrial engineers often prefer this pump type.

Where Are Split Case Pumps Used?

Split case pumps are used across many industries due to their stability and capacity.

1. Municipal Water Supply

  • Water treatment plants

  • Raw water intake stations

  • City distribution networks

  • Booster stations

2. HVAC & District Cooling

  • Cooling water

  • Chilled water circulation

  • Central air-conditioning plants

3. Industrial Applications

  • Process cooling

  • Factory water transfer

  • Filtration systems

  • Paper mills, steel plants, chemical plants

4. Irrigation and Agriculture

  • Long-distance irrigation pipelines

  • Farm water supply

5. Fire Fighting Systems

  • High-flow fire pumps

  • Hydrant supply lines

6. Large Commercial Buildings

  • Hotels, airports, malls

  • Skyscrapers' water systems

Types of Split Case Pumps

1. Horizontal Split Case Pump

  • Most common type

  • Easy maintenance

  • High flow rates

2. Vertical Split Case Pump

  • Saves floor space

  • Suitable for pump rooms with limited area

  • Same double-suction design, but vertical structure

Split Case Pump vs End Suction Pump: What’s the Difference?

Feature Split Case Pump End Suction Pump
Flow Very large Small–medium
Stability Extremely stable Stable
Maintenance Easy (split casing) Easy (back pull-out)
Cost Higher Lower
Applications Municipal, industrial, large projects General water transfer, HVAC

 

How to Select a Split Case Pump

  • Flow rate (m³/h / gpm)

  • Head (m)

  • Liquid temperature

  • Rotation speed (1450/2900 rpm)

  • Inlet pressure

  • NPSH requirements

  • Material (CI, DI, SS, Bronze)

  • Installation space (horizontal or vertical)

Are Split Case Pumps Suitable for 24/7 Operation?

Yes — split case pumps are specifically designed for:

  • continuous operation

  • long duty cycles

  • stable hydraulic performance

This is why they are popular for water plants, industrial systems, and district cooling.

Conclusion: Why Split Case Pumps Matter in Modern Engineering

Split case pumps combine:

  • high flow capacity

  • excellent efficiency

  • low vibration

  • long service life

  • easy maintenance

As a result, they are among the most trusted pump types for municipal, industrial, HVAC, irrigation, and fire systems across the globe.

 

If you need help choosing the right split case pump for your project, our engineering team is ready to assist with selection, performance data, and OEM/ODM support.

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