At Sunair Co., we understand the significance of selecting the right-size centrifugal pump for your industrial systems. Whether you need a small pump for cooling applications or a large pump for heavy-duty tasks, we offer a wide range of sizes and models to meet your unique requirements.
Understanding Centrifugal Pumps & Applications
Centrifugal pumps utilize the movement of an impeller, a rotating component with curved blades that spins rapidly to generate centrifugal force that moves the fluid outward from the center to the outer edges—creating low-pressure and high-pressure zones, respectively.
The fluid enters the pump through a suction nozzle and enters the center of the impeller. The fluid gains kinetic energy as the impeller accelerates it to a higher velocity. An increasing cross-sectional area volute then slows the liquid down and converts velocity to pressure as the fluid exits the pump.
While centrifugal pumps come in a variety of shapes, sizes, and materials, basic components include an impeller, volute casing, back cover or seal chamber, shaft and bearings, baseplate, and a motor or other driver such as an engine or a steam turbine.
Other common system components usually include piping, valves, pressure, flow or temperature gauges, tanks, and monitoring and control devices such as variable frequency drives, transmitters or switches.
There are different types of centrifugal pumps for different jobs, including:
- End suction centrifugal pumps are the most common type, designed with a single inlet and discharge port, and typically used for water or chemical supply, recirculation, and loading, unloading, or transfer applications.
- Inline centrifugal pumps feature a horizontal or vertical (most common) configuration and are used in applications where the pump is able to be mounted directly inline with the piping system, often saving considerable space over other configurations.
- Multistage centrifugal pumps have multiple impellers mounted on a single shaft and are used in applications that require high pressures, such as boiler feed, high-pressure wash down or cleaning, and high-pressure process applications such as chemical injection.
- Submersible centrifugal pumps are designed to be submerged in the fluid being pumped and commonly used for dewatering, wastewater treatment, and sump pump applications.
- Self-priming centrifugal pumps have the ability to prime automatically, which means they can be used in applications where the pump may be located above the fluid level.
- Vertical lineshaft pumps include multi-stage turbines and single-stage sump pumps, usually with the motor and the discharge connection mounted at grade, and of sufficient length to submerge the impeller(s) in the pumped fluid.
Overall, the choice of centrifugal pump type will depend on your specific industry, application requirements, available facility space, and factors such as the properties of the fluid being pumped.
What to Consider When Choosing the Right-Size Centrifugal Pump
One of the key factors in ensuring optimal pump performance is selecting the correct pump size for your specific application, since this directly impacts its ability to handle the required flow rate, pressure, and other system parameters.
Choosing the wrong size pump can lead to inefficiencies, increased energy consumption, premature wear and tear, and even system failures.
Here are some key considerations when selecting the proper centrifugal pump for your application: Try to keep in mind and specify what the normal operating values, as well as the expected minimum and maximum values, will be for each of these important parameters:
- Flow Rate: The flow rate of the fluid being pumped is the most important factor to consider when choosing a centrifugal pump because it determines the volume the pump can move per unit of time, ensuring that the system can meet desired production or operational requirements.
- Differential Head or Pressure: The differential head of a centrifugal pump consists of a static head and frictional head. The former is the vertical elevation difference plus any static system pressure to be overcome, while the latter is dependent on the design of the piping system and varies according to flow. Head is typically measured in feet or meters for centrifugal pumps.
- Specific Gravity: This is the ratio of the fluid's density to that of water. It is a factor when calculating differential head from a given differential pressure. Specific gravity also proportionally affects a pump’s power requirement.
- Viscosity: This is a measure of the fluid's resistance to flow. Higher viscosity fluids cause a decrease in pump efficiency and an increase in a system’s differential head at a given flow, requiring a larger pump, larger impeller diameter and higher horsepower, to achieve the required flow rate. Fluid viscosity for a centrifugal pump has a practical limit of anywhere between 200 and 1000 cP, depending on the pump design and application, beyond which a positive-displacement or disc pump should be considered.
- Suction Pressure: Heavier-duty pumps, bearing systems, mechanical seals, motors are required to handle systems with higher suction pressures.
- Temperature: The temperature of the fluid being pumped affects the pump size and type, materials of construction, and variety of mechanical seal. High temperatures cause thermal growth and often a centerline-mounted pump is preferred to limit the effect of this thermal growth on the creation of pipe strain. Sealless magnetic-drive pumps are sometimes selected for high temperature applications for their increased safety.
- Vapor Pressure & Specific Heat: The vapor pressure increases with temperature. It is important to quantify for applications involving hot water, industrial chemicals, or hydrocarbons, so that mechanical seals and materials can be properly specified. Vapor pressure is an important property to understand to properly calculate NPSHA of a system.
- NPSHA: Net Positive Suction Head Available represents the amount of suction energy available from a pumping system. Often overlooked, it is a key factor to ensuring reliable operation. It is important to have NPSHA higher than the NPSHR (Net Positive Suction Head Required) of the selected pump by some margin— typically at least 3 feet or 1 meter, and sometimes higher depending on the pumped liquid and application—in order for the pumped fluid to enter the pump with enough energy to remain a liquid. Insufficient NPSH margin causes cavitation, where vapor bubbles form at the pump suction due to low pressure, and then collapse violently as pressure is added to the liquid, causing damage to pump components. The distinct sound of cavitation is often described as pumping "gravel" or "rocks." It is crucial to consider NPSHA to prevent cavitation and maintain pump efficiency.
No matter what your operational requirements or industrial applications, Sunair’s team of qualified experts will assess your existing systems, evaluate your operational needs, and recommend the perfect pumps to deliver optimal performance, efficiency, and longevity.
Common Industrial Uses for Different Centrifugal Pump Sizes
Centrifugal pumps play a vital role in a wide range of industrial applications, and their effectiveness greatly depends on selecting the correct size for a specific task.
Choosing the right centrifugal pump for your application is essential to ensure safe and reliable operations.
Here are several of the most common uses for centrifugal pumps of different sizes:
Small
Small centrifugal pumps are extremely versatile, and commonly used in a variety of industrial applications where the flow rate and pressure requirements are relatively low, including:
- Cooling Systems
- Chemical Transfers
- Water Transfers
- Irrigation
- Oil Transfer
Medium
Medium-sized centrifugal pumps are needed for applications requiring moderate flow rates and pressures, and often used in environments where space is limited or where smaller centrifugal pumps are not powerful enough to meet the application's needs, such as:
- Water Treatment
- HVAC Systems
- Manufacturing
- Agriculture
- Food & Beverage Production
Large
Large centrifugal pumps are critical to a range of industrial applications where high flow rates and pressures are required. They are designed to handle large volumes of fluids, and often used in demanding environments where reliability and performance are essential, including:
- Water Supply
- Oil & Gas Industry
- Power Generation
- Chemical Processing
- Mining
Work With Sunair to Find the Proper Centrifugal Pump for Your Operations
Once you have considered all the necessary factors, it's important to consult with an industrial pump supplier such as Sunair Co. to ensure that you’re selecting the correct type and size centrifugal pump for your application.
Sunair Co. can help you determine the optimal pump size and specifications to meet your needs, and our dedicated service and repair center provides valuable support for your pump systems—start-up, reliability upgrades, preventive maintenance, breakdown services, and more—to keep your pumps running better, for longer.
Contact Sunair to outfit your facilities with the right centrifugal pump equipment today!
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